37 Common Surgical Procedures - Bài viết - Bệnh Học
Đọc và ngẫm: "Rượu nhạt uống lắm cũng say. Người khôn nói lắm dẫu hay cũng nhàm. [Ngạn ngữ Việt nam ] "
Chú ý: Các nội dung sai QUY ĐỊNHLuật chính tả sẽ bị XÓA
Nếu bạn đang gởi bài, hãy đọc qua bài này!


37 Common Surgical Procedures

Cho điểm
Common Surgical Procedures
Li Ern Chen
Bradley D. Freeman
This chapter reviews concepts, indications, and technical aspects of procedures commonly performed in hospitalized surgical patients, focusing on central venous catheterization, thoracic and peritoneal drainage procedures, airway access, and laparoscopy.
Basic rules govern the successful performance of surgical procedures: (1) Necessary equipment, supplies, lighting, and assistance should be available prior to starting the procedure; (2) the patient should be positioned to optimize exposure; (3) patient comfort must be ensured, and appropriate analgesia and sedation must be provided so that the patient can cooperate with and tolerate the procedure; and (4) sterile technique should be practiced when appropriate
I. Central Venous Catheterization
Central venous catheterization is commonly used in surgical patients both for diagnosis [central venous pressure (CVP) determination] and treatment (fluid infusion, mechanical device, (e.g., pacemaker or inferior vena cava filter insertion). Several approaches to the central venous system exist, each with advantages and disadvantages. Before placement of a central venous access device (CVAD), the patient should be evaluated for the presence of an indwelling central venous device, such as a transvenous pacemaker, and signs of central venous obstruction, such as distended collateral veins about the shoulder and neck. Contraindication: Venous thrombosis is an absolute contraindication to catheter placement at the affected site. Relative contraindications include coagulopathy [International Normalized Ratio (INR) >2 or partial prothrombin time (PTT) >2 times control] refractory to correction and thrombocytopenia (platelet count <50,000/µL). For an elective procedure, the INR should be corrected to less than 1.5, PTT to less than 1.5 times control, and platelet count to greater than 50,000/µL.
A. Types of catheters
Catheters are classified on the basis of number of lumens, location (artery, vein), lifespan (short, intermediate, long term), site of insertion (subclavian, internal jugular, femoral, peripheral), subcutaneous tunneling, anti-infective features (Dacron and/or antibiotic cuff, heparin, or antibiotic impregnation), and tip structure (valved, nonvalved).

  • Short-term (nontunneled) CVADs. The advantages of single-lumen and multilumen nontunneled catheters include low cost, bedside placement and removal, and ease of exchange of damaged catheters. Examples include the triple-lumen catheter, the Mahurkar catheter, and the Hemo-Cath pheresis catheter.
  • Intermediate-term, peripherally inserted CVADs. Peripherally inserted central catheters (PICCs) are composed of Silastic or polyurethane and can be kept in place for up to 6 months. These are commonly used for home total parenteral nutrition (TPN) or intravenous antibiotic administration (4 to 12 weeks). PICCs can be inserted using local anesthetic at the bedside via cephalic, basilic, or median cubital veins. Proper position should be radiographically documented. These catheters have low risk of insertion-related complications, such as pneumothorax, and infection. Disadvantages of PICCs result from their small diameter and length (40 to 60 cm), including problems with withdrawal occlusion and risk for thrombophlebitis (JVIR 2000;11:1309).
  • Intermediate-term, nontunneled CVADS. These catheters contain a silver-impregnated gelatin cuff (Vitacuff), which is designed to be positioned subcutaneously and to serve as a barrier to migration of bacteria from the skin. The gelatin dissolves within a short time, facilitating removal. The Hohn catheter is the prototypical CVAD of this type, and it may remain in place for as long as 6 months.
  • Long-term, tunneled CVADS. Tunneled catheters enable indefinite venous access for prolonged nutritional support, chemotherapy, antibiotics, hemodialysis, or blood draws. The subcutaneous portion of the catheter contains a double cuff that functions to induce scar formation, anchoring the catheter in place and preventing bacterial migration from skin. Most tunneled catheters are manufactured using silicone, which is more flexible and durable than other materials. Examples include the Hickman and Broviac catheters. The Groshong catheter differs by the presence of a slit valve at the tip, which seals it from the bloodstream. Unlike other catheters, which require daily or weekly heparinized saline injections, Groshong catheters are flushed with normal saline, and thus they are well suited for patients with history of heparin allergy or heparin-induced thrombocytopenia.
  • Implanted venous ports. Ports are used primarily for chronic therapy (>6 months) and for which only intermittent access is needed. Common indications include chemotherapy and frequent hospitalization (e.g., patients with sickle cell disease or cystic fibrosis). Access is preferably obtained via the internal jugular vein and a reservoir placed in a subcutaneous pocket created in the infraclavicular fossa. Smaller port devices (e.g., PASport) are designed for upper-extremity implantation. Most models contain a silicone or polyurethane catheter connected to a metal or plastic reservoir with a dense silicone septum for percutaneous needle access. Advantages of ports over other CVADs include a lower incidence of infection and less maintenance (monthly heparin flushes when not in use). Plastic ports are magnetic resonance scan compatible (e.g., MRI port) and are as durable as ports with reservoirs constructed of metal. Port access requires skin puncture using a special noncoring (Huber) needle to prevent deterioration of the septum.

B. Internal jugular approach

  • Indications. The internal jugular vein is easily and rapidly accessible in most patients. Advantages of this site include decreased risk of pneumothorax compared with the subclavian approach and ready compressibility of the vessels in case of bleeding. For the unsedated or ambulatory patient, this may be an uncomfortable site and may hinder his or her neck movement. Maintaining a sterile dressing on the insertion site can be difficult. This is a commonly used site of central venous access for placement of tunneled catheters and ports where the catheter's exit site is on the chest.
  • Technique. Imaging devices (such as ultrasound) are being increasingly used to delineate the vascular anatomy and enhance the safety of vascular access procedures. If available, such devices should be used, particularly in patients in whom anatomic landmarks are obscure. The pulse of the common carotid artery is palpated at the medial border of the sternocleidomastoid (SCM) muscle at mid-neck. The internal jugular vein is located lateral to the common carotid artery and courses slightly anterior to the artery as it joins the subclavian vein (Fig. 37-1). Two equally effective approaches to the internal jugular vein are described: the central and posterior approaches. The physician stands at the head of the bed. The patient is placed in the Trendelenburg position at an angle of 10 to 15 degrees with his or her head flat on the bed and turned away from the side of the procedure. The skin is prepared with 70% propanal/0.5% chlorhexidine followed by 10% povidone-iodine, which has been shown in a prospective randomized trial (J Intens Care Med 2004;30:1081) to be superior in prevention of catheter colonization. One percent (1%) lidocaine is infiltrated subcutaneously over the belly and lateral border of the SCM. For the central approach, a 21-gauge “seeker” needle is introduced approximately 1 cm lateral to the carotid pulse into the belly of the SCM. At a 45-degree angle, the needle is slowly advanced toward the ipsilateral nipple. For the posterior approach, the seeker needle is introduced at

the lateral edge of the SCM and directed toward the sternal notch at a 45-degree angle. The vein should be entered within 5 to 7 cm with both approaches. If the vein is not entered, the needle should be withdrawn and redirected for another attempt. Redirection of the needle should be done just below the surface of the skin because of the potential of the needle tip to lacerate adjacent vessels. Constant negative pressure is exerted on the syringe, and entry into the vein is confirmed by the return of venous blood. A 14-gauge needle is then introduced just inferior to the seeker needle and is advanced along the same path until venous blood is aspirated. The Seldinger technique is carried out, whereby a flexible guidewire is passed into the vein through the 14-gauge needle, the needle is removed over the wire, and a nick is made in the skin at the puncture site to allow passage of the dilator. It is important to maintain control of the guidewire at all times. The dilator creates a tract for the passage of the less rigid central venous catheter. The catheter is introduced over the wire and advanced to 15 to 20 cm so that its tip is at the junction of the superior vena cava (SVC) and the right atrium. In patients with difficult anatomy or indwelling devices (vena cava filters, pacemakers), fluoroscopy may be used to guide placement. Aspiration of blood from all ports and subsequent flushing with saline confirm that the catheter is positioned in the vein and that all of its ports are functional. The catheter is then secured to the patient's neck at a minimum of two sites, and a sterile dressing is applied. A chest x-ray is obtained to confirm the location of the catheter tip and to rule out the presence of a pneumothorax.
Figure 37-1. Anatomy of the upper chest and neck, including the vasculature and important landmarks. SVC, superior vena cava.

  • Complications
    • Pneumothorax. All percutaneously placed neck lines carry a risk of pneumothorax. Every attempt at placement of a central venous catheter, successful or unsuccessful, should be followed by an erect chest x-ray before the catheter is used or line placement is attempted at another site.
    • Carotid artery injury. Carotid artery puncture complicates internal jugular cannulation in as many as 10% of cases, representing 80% to 90% of all insertion-related complications. Inadvertent carotid artery puncture is usually tolerated in the noncoagulopathic patient and treated by direct pressure over the carotid artery. If the carotid artery is punctured, no further attempts at central venous access should be made on either side of the patient's neck and the patient must be observed for the development of a neck hematoma and resultant airway compromise. Although carotid artery puncture is usually benign, it can be life threatening when it results in inadvertent intra-arterial cannulation,

stroke, hemothorax, or carotid artery–internal jugular vein fistula. In the hemodynamically unstable or poorly oxygenating patient, it is not always possible to distinguish venous blood from arterial blood by appearance. This can lead to inadvertent cannulation of the carotid artery. If the dilator or catheter is 7 French or smaller, it can usually be removed and direct pressure held over the carotid puncture site without further detrimental sequelae. Catheters larger than 7 French should be removed in a setting in which operative repair of the arteriotomy can be performed.

    • Guidewire-related complications. Advancement of the guidewire into the right atrium or ventricle can cause arrhythmia, which usually resolves once the wire is withdrawn. Central venous catheter insertion in patients with indwelling devices (such as vena cava filters or pacemakers) must be performed under fluoroscopic guidance to minimize the possibility of entanglement of the guidewire with these structures.
    • Venous stenosis. Venous stenosis can occur at the site where the catheter enters the vein, which can lead to thrombosis of the vessel. Because the upper extremities and neck have extensive collateralization, stenosis or thrombosis is usually well tolerated.
    • Other. Air embolus, perforation of the right atrium or ventricle with resultant hemopericardium and cardiac tamponade, and injury to the trachea, esophagus, thoracic duct, vagus nerve, phrenic nerve, or brachial plexus can all complicate the placement of central venous catheters.

  • Catheter-related bloodstream infection (CRBSI) occurs with a prevalence ranging from 3% to 7% and has a mortality rate of up to 15% (Infect Control Hosp Epidemiol 2000;21:375). Catheter colonization—or bacterial growth from the catheter tip—occurs in 20% of central venous catheters.
    • Epidemiology. CRBSIs are generally caused by coagulase-negative staphylococci (37%), followed by enterococci (13.5%), coagulase-positive Staphylococcus aureus (12.6%), and Candida albicans (8%). Treatment of these organisms has become increasingly difficult now that 60% of S. aureus isolates and 90% of coagulase-negative Staphylococcus isolates are resistant to oxacillin. The percentage of enterococcal isolates resistant to vancomycin has also increased, from 0.5% in 1989 to 28.5% in 2003 (Am J Infect Control 2004;32:470). For lower-extremity CVAD, Gram-negative rods represent the most frequent organisms of infection, along with enterococci. The majority of catheter infections are monomicrobial.
    • Pathogenesis. Infection occurs by two routes. First, endogenous skin flora at the insertion site migrate along the external surface of the catheter and colonize the intravascular tip. Second, pathogens from contamination at the hub colonize the internal surface of the catheter and are washed into the bloodstream when the catheter is infused. Occasionally, catheters may become hematogenously seeded from another focus of infection. Rarely, infusate contamination or break in sterile technique leads to CRBSI.
    • Definitions and diagnosis. Catheter colonization is defined as greater than 15 colony-forming units of microorganisms on semiquantitative culture. The definition of CRBSI requires bacteremia or fungemia in a patient with CVAD and meeting of the following criteria: (1) clinical signs of infection (fever, chills, tachycardia, hypotension, leukocytosis), (2) no identifiable source for bloodstream infection other than the CVAD, and (3) isolation of the same organism from semiquantitative culture of the catheter and from the blood (drawn from a peripheral vein taken within 48 hours of each other) (Clin Infect Dis 2001;32:1249). Diagnosis of CRBSI with coagulase-negative staphylococci requires two positive blood cultures or a positive catheter culture.
    • Presentation. Catheter infections may manifest with local, regional, or systemic signs.
      • Local catheter-related infections. Exit-site infections may present with erythema and drainage. In the absence of systemic signs and negative blood cultures, treatment consists of routine antibiotics for skin flora and more

frequent dressing changes and care. Catheter removal is required in only about 10% of cases.

      • Regional catheter infections. Tunnel infections or pocket infections present with erythema, induration, and tenderness along the catheter tract or over the pocket, often with a clear demarcation of the affected area. Often there are systemic manifestations (e.g., leukocytosis, positive blood culture). If regional infection is diagnosed, the CVAD is usually removed, and in some cases, the tunnel or pocket is débrided. Antibiotic treatment alone is rarely successful.
      • Bacteremia. Bacteremia is the most severe manifestation of a catheter-related infection. In the setting of bacteremia, indwelling catheters generally should be removed. However, in patients with limited access and other potential sources for infection, broad-spectrum antibiotics can be initiated and continued for 10 to 14 days. Persistent bacteremia requires catheter removal. One exception is the presence of fungemia, which requires the catheter to be removed, with immediate initiation of antifungal treatment.

    • Risk factors. Several factors increase the risk of CVAD-related infections, including neutropenia, malignancy, parenteral feeding, intensive care unit (ICU) admission, mechanical ventilation, hyperalimentation, increasing number of catheter lumens, and thrombus. The risk for infection varies with the catheter insertion site, with the femoral vein associated with a much higher infection rate than subclavian vein access (19.8% vs. 4.5%) (JAMA 2001;286:700). Jugular venous catheterization carries an intermediate risk of infection. The likelihood of infection directly correlates with length of time a catheter has been in position.
    • Antimicrobial-impregnated catheters. Antimicrobial-coated catheters, ionic silver cuffs, antibiotic-impregnated hubs, and intraluminal antibiotic locks have all been shown to reduce the incidence of CRBSI in critically ill patients and should be used in this patient population. In a multicenter, randomized, double-blind, controlled trial, second-generation chlorhexidine-silver sulfadiazine (CHSS)–impregnated CVADs reduced microbial colonization compared to uncoated catheters (Ann Intern Med 2005;143:570). In addition, a recent meta-analysis found that rifampin/minocycline–impregnated CVADs reduced the rate of microbial colonization and CRBSI (J Antimicrob Chemother 2007;59:359). Comparison of second-generation CHSS-coated catheters to rifampin/minocycline–impregnated catheters has not been made. The emergence of resistant organisms resulting from the use of antimicrobial-impregnated catheters remains a potentially important concern.
    • Routine (elective) catheter replacement. Routine catheter replacement (either changing position to a new site or rewiring an existing catheter after an arbitrary length of time) has not been demonstrated to decrease the incidence of catheter-related infections. Thus, CVADs should be left in place until discontinuation is clinically indicated.

C. Subclavian vein approach

  • Indications. The subclavian approach to the central venous system is generally most comfortable for the patient and easiest to maintain. The Centers for Disease Control and Prevention (CDC) published guidelines in 2002 that recommend subclavian access as the preferred site in patients at risk for CVAD infection (MMWR Recomm Rep 2002;51:1). A prospective observational study found that CRBSI incidence was lowest in subclavian access, higher in jugular access, and highest in femoral access, and recommended that sites for CVAD placement be considered in that order (Crit Care 2005;9:R631). In the presence of an open wound, tracheostomy, and tumors of the head and neck, CVAD should be placed in the subclavian position to minimize infectious risk.
  • Technique. The subclavian vein courses posterior to the clavicle, where it joins the internal jugular vein and the contralateral veins to form the SVC (Fig. 37-1). The subclavian artery and the apical pleura lie just posterior to the subclavian vein. The patient is placed in the Trendelenburg position with a rolled towel between

the scapulas, which allows the shoulders to fall posteriorly. The skin is prepared with 70% propanal/0.5% chlorhexidine followed by 10% povidone-iodine, and 1% lidocaine is infiltrated subcutaneously in the infraclavicular space near the middle and lateral third of the clavicle. The infusion is carried into the deep soft tissue and to the periosteum of the clavicle. A 14-gauge needle is introduced at the middle third of the clavicle in the deltopectoral groove. The needle is kept deep to the clavicle and parallel to the plane of the floor and is slowly advanced toward the sternal notch. Constant negative pressure is applied to the syringe. Once the needle enters the subclavian vein, the guidewire, dilator, and catheter are introduced using the Seldinger technique. As with the other approaches, all catheter ports are aspirated and flushed to ensure that they are functional. A chest x-ray is obtained to confirm the location of the catheter tip and to evaluate for pneumothorax.

  • Complications. The complications of subclavian venous catheterization include those described in the previous section. Puncture of the subclavian artery can be troublesome because the clavicle prevents the application of direct pressure to achieve homeostasis. Therefore, this approach should be avoided in the patient with uncorrectable coagulopathy. If the artery is punctured, the patient should be placed on hemodynamic monitoring for the next 30 to 45 minutes to ensure that bleeding is not ongoing. Inadvertent cannulation of the subclavian artery with the dilator or catheter is a potentially fatal complication. The dilator or catheter should be left in place and an angiogram performed. Removal of the catheter should be done in the operating room so that open arteriotomy repair may be performed if necessary. Particular attention must be paid to the placement of left subclavian catheters to avoid injuring the thoracic duct, brachiocephalic vein, and SVC with the needle or dilator. Attention must be paid to the final position of the catheter tip when placed on the left side to avoid abutting the SVC wall, which poses the immediate or delayed risk of SVC perforation.

D. Femoral vein approach

  • Indications. The femoral vein is the easiest site for obtaining central access and is therefore the preferred approach for central venous access during trauma or cardiopulmonary resuscitation. This approach does not interfere with the other procedures of cardiopulmonary resuscitation. It should be remembered that a femoral vein catheter does not actually reach the central circulation and may not be ideal for the administration of vasoactive drugs. This may be the only site available in patients with upper-body burns. The femoral approach is also favored during trauma resuscitation except when there is an injury to the inferior vena cava. The femoral vein catheter inhibits patient mobility, and the groin is a difficult area in which to maintain sterility. Therefore, it should not be used in elective situations, except when upper-extremity and neck sites are not available.
  • Technique. The femoral artery crosses the inguinal ligament approximately midway between the anterosuperior iliac spine and the pubic tubercle. The femoral vein runs medial to the artery as they cross the inguinal ligament (Fig. 37-2). The skin is prepared with 70% propanal/0.5% chlorhexidine followed by 10% povidone-iodine, and 1% lidocaine is infiltrated in the subcutaneous tissue medial to the femoral artery and inferior to the inguinal ligament. The pulse of the femoral artery is palpated below the inguinal ligament, and a 14-gauge needle is introduced medial to the pulse at a 30-degree angle. It is directed cephalad with constant negative pressure until the vein is entered. The catheter is placed using the Seldinger technique. When a femoral pulse cannot be palpated, as in cardiopulmonary arrest, the position of the femoral artery can be estimated to be at the midpoint between the anterosuperior iliac spine and the pubic tubercle, with the vein lying 1 to 2 cm medial to this point. Once the catheter is successfully placed, all three ports are aspirated and flushed to ensure that they are functional.
  • Complications. Injury to the common femoral artery or its branches during cannulation of the femoral vein can result in an inguinal or retroperitoneal hematoma,

a pseudoaneurysm, or an arteriovenous fistula. The femoral nerve can also be damaged. Injury to the inguinal lymphatic system can result in a lymphocele. The possibility of injuring peritoneal structures also exists, particularly if an inguinal hernia is present. Errant passages of the guidewire and the rigid dilator run the risk of perforating the pelvic venous complex and causing retroperitoneal hemorrhage. Late complications include infection and femoral vein thrombosis.
Figure 37-2. Anatomy of the femoral vessels.
E. Catheter maintenance
Proper care of access sites and devices is crucial to their long-term function. Short-term and tunneled CVADs require sterile, occlusive, transparent dressings that are changed weekly by trained personnel using meticulous technique. More frequent dressing changes may be needed for those patients who are immune compromised. Application of topical antibiotic beneath an occlusive dressing may provide a moist culture medium for bacterial growth. Catheter lumens should be flushed on a regular basis to prevent thrombosis.
F. Thrombosis
Thrombosis (J Natl Compr Cancer Netw 2006;4:889). Difficulty in aspirating blood or infusing fluid may be indicative of partial or complete catheter blockage. Blockage may be due to kinking of the catheter, occlusion of the catheter tip on a vessel wall, or luminal thrombosis. The spectrum of thrombotic complications ranges from fibrin sleeve formation around the catheter to mural or occlusive thrombus. Although only 3% to 5% of central venous catheters develop clinically significant thromboses, ultrasonography with color Doppler imaging has been found to detect venous thrombosis in 33% to 67% of patients when the indwelling time of the CVAD was greater than 1 week. A negative Doppler ultrasound in a symptomatic patient should be followed by venographic assessment because thrombi in the central upper venous system (superior vena cava, brachiocephalic, and subclavian veins) are better detected by venography.
  • Patient-related risk factors include prothrombotic states associated with underlying coagulation disorders, malignancy, chronic disease, hydration state, nutritional status, and prior history of CVAD placement
  • Catheter-related risk factors include size, position, infection, and duration of placement. Risk of catheter-related thrombosis varies according to site of insertion, with reported rates of 21.5% in femoral catheters compared to only 1.9% with subclavian access (p <0.001) (JAMA 2001;286:700). Catheters in the subclavian or innominate veins are at higher risk for producing symptomatic central venous stenosis than are those that are placed in the right internal jugular vein.

More-pliable and smoother catheter material, such as silicone, is less thrombogenic than stiffer materials, such as polyurethane. Risk of infection is strongly correlated to the presence of thrombus. Regular flushing protocols may reduce the incidence of thrombotic complications.

  • Intervention. Thrombolytic intervention with urokinase or alteplase is generally an effective and safe means of restoring CVAD function and blood flow without resorting to catheter replacement. If this procedure fails or if the patient is symptomatic, the catheter should be removed and systemic anticoagulation should be initiated.

II. Thoracic Drainage Procedures
A. Thoracentesis

  • Indications. Diagnostic thoracentesis is indicated for pleural effusion of unknown etiology. Pleural effusions are categorized as transudative or exudative. This differentiation is based on its gross, microscopic, and biochemical characteristics. Several laboratory studies are available for studying pleural fluid. A pleural fluid–serum lactate dehydrogenase (LDH) ratio greater than 0.6 and a fluid–serum protein ratio greater than 0.5 indicate an exudative effusion, whereas a fluid–serum LDH ratio less than 0.6 and a fluid–serum protein ratio less than 0.5 indicate a transudative effusion. Fluid pH, glucose level, amylase level, and lipid level may be measured when analyzing pleural fluid to aid in diagnosis. Cytologic examination for malignant cells should be obtained when a malignant effusion is considered. If an infectious etiology is suspected, Gram stain and culture for bacteria and fungi are necessary. Therapeutic thoracentesis is indicated to relieve shortness of breath or discomfort from large pleural effusions. When repeated therapeutic thoracentesis is needed to treat recurrent pleural effusions, chest tube drainage and pleurosclerosis should be considered.
  • Technique. Erect and lateral decubiti chest radiographs or equivalent imaging studies [such as computed tomography (CT) scanning] should be obtained to assess the size and location of the effusion as well as whether the effusion is free flowing or loculated. For free-flowing effusions, the patient is seated upright and slightly forward. The thorax should be entered posteriorly, 4 to 6 cm lateral to the spinal column and one to two interspaces below the cessation of tactile fremitus and where percussion is dull. Loculated effusions can be localized by ultrasonography, and the site for thoracentesis is marked on the skin. The site is prepared with povidone-iodine and draped with sterile towels. Lidocaine 1% is infiltrated into the subcutaneous tissue covering the rib below the interspace to be entered. The infiltration is carried deep to the periosteum of the rib. Next, with negative pressure placed on the syringe, the needle is advanced slowly over the top of the rib to avoid injury to the neurovascular bundle. The needle is advanced until pleural fluid is returned; then it is withdrawn a fraction, and lidocaine is injected to anesthetize the pleura. Lidocaine is then infiltrated into the intercostal muscles as the needle is withdrawn.

Most thoracentesis kits contain a long, 14-gauge needle inserted into a plastic catheter with an attached syringe and stopcock. The needle-catheter apparatus is introduced at the level of the rib below the interspace to be entered. With negative pressure applied to the syringe, the needle is slowly advanced over the top of the rib and into the pleural cavity until fluid is returned. Aspiration of air bubbles indicates puncture of the lung parenchyma; the needle should be promptly removed under negative pressure. Once the needle is in the pleural space, the catheter is advanced over the needle toward the diaphragm. Special attention is taken not to advance the needle as the catheter is being directed into the pleural space. A drainage bag is attached to the stopcock to remove the pleural fluid. The amount of fluid removed depends on the indication for the thoracentesis. A diagnostic thoracentesis requires 20 to 30 mL of fluid for the appropriate tests, and a therapeutic thoracentesis can drain 1 to 2 L of fluid. A chest x-ray should be obtained after the procedure to evaluate for pneumothorax and resolution of the effusion.

  • Complications. Pneumothorax is the most common complication of thoracentesis. It must be treated with a tube thoracostomy and negative suction until the air leak seals. An exception is that if the pneumothorax is small and the patient is stable with regard to hemodynamics and respiratory status, one may check another chest radiograph in 6 hours. Re-expansion pulmonary edema can occur in rare situations when a large amount of fluid is removed. Hemothorax, infection, injury to the neurovascular bundle, and subcutaneous hematoma are other potential complications.

B. Tube thoracostomy

  • Indications and contraindications. Tube thoracostomy is indicated for a pneumothorax, hemothorax, recurrent pleural effusion, chylothorax, and empyema. Profound coagulopathy is a relative contraindication to the placement of a chest tube, and efforts should be made to correct the coagulopathy before the tube is placed.
  • Tubes. The size of the thoracostomy tube needed depends on the material to be drained. Generally, a 32- to 36-French tube is used for the evacuation of a hemothorax or pleural effusion. In a pneumothorax, a 24- to 28-French tube is used. Alternatively, a percutaneous small-bore (18-French) chest tube (Thal-Quik) can be placed by Seldinger technique.
  • Anatomy. A good understanding of thoracic anatomy is needed to prevent injuries to the lung parenchyma, diaphragm, intercostal neurovascular bundles, and mediastinum during chest tube placement. The lung may have adhesions to the chest wall that make insertion and advancement of the thoracostomy tube difficult. The intercostal neurovascular bundle runs in a groove on the inferior aspect of each rib; therefore, the tube should be passed over the top of the rib to avoid injury. Because during normal respiration, the diaphragm can rise to the level of the fourth intercostal space, insertion of the chest tube lower than the sixth interspace is discouraged.
  • Technique. The patient is placed in the lateral position with the unaffected side down, and the head of the bed is inclined 10 to 15 degrees. The patient's arm on the affected side is extended forward or above the head. With the skin prepared, 1% lidocaine is infiltrated over the fifth or sixth rib in the middle or anterior axillary line by the technique described in the previous section. A 2- to 3-cm transverse incision is made through the skin and subcutaneous tissue. A curved clamp is used bluntly to dissect an oblique tract to the rib (Fig. 37-3A). With careful spreading, the clamp is advanced over the top of the rib. The parietal pleura is punctured with the clamp, and an efflux of air or fluid is usually encountered. A finger is introduced into the tract to ensure passage into the pleural space and to lyse any adhesions at the point of entry (Fig. 37-3B), ensuring that there is no lung adherent to the thoracic wall. With the clamp as a guide, the chest tube is introduced into the pleural space (Fig. 37-3C); the tube is directed posteriorly or basally for a dependent effusion and apically for a pneumothorax. A clamp placed at the free end of the chest tube prevents drainage from the chest until the tube can be connected to a closed suction or water-seal system. The chest tube is advanced until the last hole of the tube is clearly inside the thoracic cavity. When the tube is positioned properly and functioning adequately, it is secured to the skin with two heavy silk sutures and covered with an occlusive dressing to prevent air leaks. A U-stitch around the chest tube is commonly placed to be used as a purse-string suture to close the tract once the tube is removed. A chest x-ray is obtained after the procedure to assess re-expansion of the lung and the tube position. Under certain circumstances, radiographic guidance is required for tube placement (e.g., loculated pleural effusion, prior thoracic surgery).
  • Complications. Low placement of a chest tube can result in injury to the diaphragm and adjacent viscera. Failure to guide the tube into the pleural space can result in dissection of the extrapleural plane. This can be a difficult diagnosis, but anteroposterior and lateral chest radiographs should reveal a lung that

has failed to re-expand and suggest a chest tube placed outside the thorax. The tube should be removed and placed within the thoracic cavity to re-expand the lung. Parenchymal or hilar injuries or cardiac injuries can occur with overzealous advancement of the tube or dissection of pleural adhesions. Other complications include subcutaneous emphysema, re-expansion pulmonary edema, phrenic nerve injury, esophageal perforation, contralateral pneumothorax, and neurovascular bundle injury. Late complications include empyema, infection along the chest tube tract, and abscess. Infectious complications may be minimized by following strict sterile technique during thoracostomy tube placement.
Figure 37-3. Tube thoracostomy placement. A: Pleural space entered by blunt spreading of the clamp over the top of the adjacent rib. B: A finger is introduced to ensure position within the pleural space and to lyse adhesions. C: The chest tube is placed into the tunnel and directed with the help of a Kelly clamp. The tube is directed posterior and caudal for an effusion or hemothorax and cephalad for a pneumothorax.
III. Peritoneal Drainage Procedure
A. Paracentesis

  • Indications. Paracentesis is a useful diagnostic and therapeutic tool. The most common indication for diagnostic paracentesis in the surgical patient is to determine whether ascites is infected. Accordingly, ascites should submitted for cell count, Gram stain, microscopy, and culture. A therapeutic paracentesis is indicated for patients with respiratory compromise or discomfort caused by tense ascites and in patients with ascites refractory to medical management. Relative contraindications include previous abdominal surgery, pregnancy, coagulopathy, and progressive liver failure with encephalopathy or hepatorenal syndrome.
  • Technique. Patients should be in a supine position. The bladder should be empty. Level of the ascites can be determined by locating the transition from dullness to tympany with percussion. Depending on the height of the ascites, a midline or lateral approach can be used. Care must be taken with the midline approach because the air-filled bowel tends to float on top of the ascites. The skin at the site of entry should be prepared and draped. Lidocaine 1% is infiltrated subcutaneously and is carried to the level of the peritoneum. For the midline approach, a needle is introduced at a point midway between the umbilicus and the pubis symphysis. For the lateral approach, the point of entry can be in the right or left lower quadrant in the area bounded by the lateral border of the rectus abdominis muscle, the line between the umbilicus and the anterior iliac spine, and the line between the anterior iliac spine and the pubis symphysis. A simple diagnostic tap can be achieved by inserting a 22-gauge needle into the peritoneal cavity and aspirating 20 to 30 mL of fluid. Constant negative pressure should be applied to the syringe, and care should be taken not to advance the needle beyond the point where ascites is encountered. For a therapeutic paracentesis, a 14-gauge needle fit with a catheter allows for efficient drainage of larger volumes of ascites. With either the midline or the lateral approach, once ascites is returned, the catheter is advanced over the needle and directed toward the pelvis. A drainage bag is attached to the catheter to collect and measure the fluid removed.
  • Complications. Injuries to the bowel or bladder can occur with paracentesis. Emptying the bladder prior to the procedure, avoiding the insertion of the needle near surgical scars, and maintaining control of the needle once inside the peritoneum will help to minimize these injuries. Intraperitoneal hemorrhage from injury to a mesenteric vessel can occur. Laceration of the inferior epigastric vessels can lead to a hematoma of the rectus sheath or the abdominal wall. In patients with large, recurrent ascites, a persistent leakage of ascites from the site of entry can result. Peritonitis and abdominal wall abscess can also result.

IV. Emergency Airway Access
A. Endotracheal (ET) intubation

  • Indications. Establishment of a secure airway is the first priority in the management of an acutely ill patient. The airway can be secured either mechanically, with an ET tube, or surgically, with a tracheostomy or cricothyroidotomy. The oral approach under direct vision is the most common method of intubating the trachea. Other approaches include nasotracheal and endoscopic intubation; however, only orotracheal intubation is described here. Relative contraindications to orotracheal intubation include maxillofacial trauma, laryngeal injury, and cervical spine injury. A thorough description of this topic is beyond the scope of this text. A brief overview of the salient aspects of this technique is provided.
  • Technique. Preoxygenation with a bag-valve-mask apparatus and 100% oxygen, suction, adequate sedation, and muscle relaxation; an appropriately sized ET tube; and a functional laryngoscope are required. Two types of laryngeal scope blades are available: a straight blade (Miller) and a curved blade (Macintosh). The straight blade may provide better visualization in children, and the curved blade may be better for patients with short, thick necks. The physician should be comfortable using either blade. With the physician at the patient's head, the head is positioned so that the pharyngeal and laryngeal axes are in alignment (Fig. 37-4A). The patient's head and neck are fully extended into the “sniffing” position. With the nondominant hand, the physician opens the patient's mouth with the thumb and index finger on the patient's lower and upper teeth, respectively. Using the middle finger, the physician sweeps the patient's tongue to the side. The oropharynx is inspected, and foreign bodies or secretions are removed. The blade of the laryngoscope is introduced and advanced with gentle traction upward and toward the patient's feet. Once the epiglottis is visualized, the tip of the blade is positioned in the vallecula. Great care must be taken not to use the handle as a lever against the patient's teeth and lips. The glottic opening and vocal cords should come into view (Fig. 37-4B). If not, gently increasing the upward and caudal traction or having an assistant place external pressure on the cricoid and

thyroid cartilage can be helpful. If the glottic opening still cannot be visualized, the blade should be removed and the patient oxygenated and repositioned prior to additional attempts. Once the glottic opening is adequately visualized, the ET tube is advanced under direct vision until the cuff passes through the vocal cords. The cuff is inserted roughly 2 cm past the vocal cords, and the patient's incisors should rest between the 19- and 23-cm markings on the tube. The stylet and laryngoscope are carefully removed while maintaining control and the position of the ET tube. The cuff is inflated, and proper position is confirmed by osculating bilateral breath sounds and determining end-tidal carbon dioxide. Once position is confirmed, the ET tube is secured to the patient. An anteroposterior chest x-ray is obtained to confirm position. Ideally, the tip of the ET tube should be 2 to 4 cm above the carina.
Figure 37-4. Orotracheal intubation. A: Fully extending the patient's head into the “sniffing” position aligns the pharyngeal and laryngeal axes. This allows for the best visualization of the airway. B: View of the larynx and airway during oral intubation of the trachea.

  • Complications. If attempts to establish a translaryngeal airway are unsuccessful and the patient cannot be manually ventilated, an emergent surgical airway must be secured (see later discussion). Intubation of the esophagus or right-main-stem bronchus can readily be diagnosed by absent breath sounds associated with epigastric gargling on manual ventilation and right-sided breath sounds with absent left-sided breath sounds, respectively. Chipped teeth, emesis and aspiration, vocal

cord injury, laryngospasm, and soft-tissue injury to the oropharynx can all complicate ET intubation.
Figure 37-5. Anatomy of the larynx.
B. Cricothyroidotomy

  • Indications. Cricothyroidotomy is indicated when attempts at oral or nasal intubation fail or maxillofacial injury prohibits oral or nasal intubation. In cases of trauma, blood or maxillofacial injuries may prevent direct visualization of the larynx; cricothyroidotomy is the procedure of choice. Other indications for a surgical airway include cervical spine injuries that preclude optimal positioning for translaryngeal intubation. Laryngeal tracheal separation and laryngeal trauma are contraindications to this procedure. Percutaneous dilational cricothyroidotomy is a safe and effective method of emergently obtaining an airway, and it is gaining widespread use.
  • Technique. Because the vast majority of cricothyroidotomies are done in emergent situations, an excellent understanding of the anatomy in the region of the trachea is necessary to minimize complications. The thyroid cartilage is easily identified in the midline of the neck (Fig. 37-5). The cricoid, the only complete cartilaginous ring, is the first ring inferior to the thyroid cartilage. The cricothyroid membrane joins these two cartilages and is an avascular membrane. Inferior to the cricoid and straddling the trachea is the isthmus of the thyroid gland. The thyroid lobes lie lateral to the trachea, and the superior poles can extend to the level of the thyroid cartilage. If time permits, the area is prepared, draped, and anesthetized with 1% lidocaine. A vertical skin incision is made. The cricoid cartilage is identified and held firmly and circumferentially in the physician's nondominant hand until the end of the procedure. With a no. 11 or 15 blade, a small, 3- to 5-cm transverse incision is made over the cricothyroid membrane. The incision is carried deep until the airway is entered through the cricothyroid membrane. The index finger of the physician's nondominant hand can be used to identify landmarks as the dissection proceeds. The tract is widened using a clamp, a tracheal dilator, or the end of the scalpel handle. The tracheostomy tube is inserted along its curve into the trachea, the cuff is inflated, and bilateral breath sounds are confirmed. If breath sounds are present, the tracheostomy is secured to the skin by suturing the tabs to the skin with heavy, nonabsorbable, monofilament suture. A chest x-ray is obtained to document the location of the tracheostomy tube and to rule out a pneumothorax. Traditionally, cricothyroidotomy was converted to a formal tracheostomy. However, it has been suggested that a cricothyroidotomy may be used long term without an increase in acute complications (South Med J 2003; 96:465).
  • Complications. Creation of a false passage when inserting the tracheostomy tube is the most common complication. This should become evident by the absence of

breath sounds and the development of subcutaneous emphysema. Pneumothorax can also occur. Injury to surrounding structures, such as the thyroid, parathyroids, esophagus, anterior jugular veins, and recurrent laryngeal nerves, can occur in situations of urgency. Subglottic stenosis and granuloma formation are potential long-term complications.
C. Percutaneous tracheostomy

  • Indications. The advantages of percutaneous tracheostomy (PT) over surgical tracheostomy (ST) are primarily related to reduced tissue trauma and ease of performance at the bedside, which avoids transportation of critically ill patients to the operating room. Several studies support the cost-effectiveness of this approach (Crit Care Med 2001;29:926). Contraindications include unstable cervical spine, inability to identify anatomic landmarks, refractory coagulopathy, and difficult oropharyngeal anatomy such that re-establishing a translaryngeal airway would be difficult in the event of airway loss. Percutaneous tracheostomy should only be performed electively.
  • Technique. This procedure should be performed under bronchoscopic guidance. The patient should be adequately sedated and positioned in a moderate degree of neck extension. The aim of the fiberoptic scope is to ensure correct initial placement of the introducer needle (midline through the second or third tracheal rings). Subsequent to this, it is used to monitor dilation of the trachea and ensure the introducer does not remain in the trachea. After an initial 1.5-cm skin incision over the first tracheal ring, blunt dissection is performed down to the level of the pretracheal fascia using a mosquito hemostat, and the existing endotracheal tube is withdrawn into the subglottic position, permitting a needle to be introduced between the first and second or second and third tracheal rings. Placement of a guidewire is followed by progressive dilation of the tracheal stoma using beveled plastic dilators (Seldinger technique). Once the stoma has been adequately dilated, the tracheostomy tube is introduced into the trachea over the same guidewire, using a dilator as an obturator. An anteroposterior chest x-ray is obtained to confirm position.
  • Complications. In many studies, there was no significant difference in the rate of intraprocedural complication between PT and ST (Chest 2000;118:1421). Postoperative complications include accidental decannulation, bleeding, and stoma infection. The complications associated with cricothyroidotomy can also occur with PT.

V. Laparoscopy
An overview of general laparoscopic principles is provided. Readers are referred elsewhere in this manual for information pertaining to specific disease processes.
A. Advantages
Laparoscopic procedures, when compared with open techniques, may result in less patient discomfort, shorter hospitalizations, and more rapid convalescence.
B. Contraindications

  • Absolute contraindications include the inability to tolerate general anesthesia and uncorrectable coagulopathy.
  • Relative contraindications
    • Prior abdominal surgery may require alternative port locations to avoid intra-abdominal adhesions and laparoscopic adhesiolysis to improve exposure.
    • Peritonitis may limit access secondary to adhesions.
    • First- and third-trimester pregnancy. Laparoscopy is more safely undertaken in the second trimester for conditions that require urgent surgical management (i.e., cannot be safely delayed until after delivery).
    • Severe cardiopulmonary disease may be exacerbated by hypercarbia that occurs secondary to insufflation of carbon dioxide and changes in pulmonary and cardiovascular mechanics during periods of increased intra-abdominal pressure. These effects can be minimized by using lower intra-abdominal pressures (8 mm Hg) in conjunction with abdominal wall lift devices.
    • Massive abdominal distention may result in an increased risk of iatrogenic bowel injury.

C. Access and pneumoperitoneum
A working space is created in the patient's abdomen by insufflating carbon dioxide after access is obtained either by a closed or open technique. Both techniques have been shown to be safe, although a recent study showed a lower complication rate with open direct insertion (Surg Laparosc Endosc Percutan Tech 2005;15:80). Optical access trocars have been advocated in the morbidly obese population (Surg Endosc 2006;20;1238).

  • Closed technique. A Veress needle is placed most commonly at the umbilicus through a small skin-stab incision. Two serial clicks are heard as the needle penetrates the fascia and peritoneum, respectively. The surgeon aspirates the needle with a 10-mL syringe partially filled with saline to look for blood or enteric contents. The surgeon injects 3 to 5 mL of saline through the needle. If any resistance is met, the syringe is most likely in the abdominal muscle or omentum and should be repositioned. If no resistance is met, the surgeon aspirates the syringe again and removes the plunger. Observing the saline pass freely into the abdomen with gravity (drop test) confirms proper intra-abdominal placement. The abdominal cavity is insufflated via an automatic pressure-limited insufflator to 10 to 15 mm Hg. The initial intra-abdominal pressure should be less than 10 mm Hg. As the abdomen expands, pneumoperitoneum is confirmed with percussion. After insufflation, the abdominal wall is stabilized manually, the Veress needle is removed, and the initial trocar and port are inserted blindly in a direction away from critical abdominal structures.
    • Elevated pressure with low flow (1 L/minute) on insufflation usually indicates placement of the Veress needle into a closed space (e.g., pre- or retroperitoneal, within the omentum).
      • First, the port's insufflation valve should be confirmed to be open.
      • If so, the Veress needle is removed and reinserted with a subsequent drop test.
      • If the needle position is in doubt, an open insertion technique should be used.

    • Return of blood, cloudy or bilious fluid, or enteric contents after Veress needle placement mandates needle repositioning and inspection of the violated abdominal organ.

  • Open insertion of the initial port uses a direct cutdown through the abdominal fascia. A Hasson (wedge-shaped) port is placed under direct vision and secured to the abdominal fascia with stay sutures.
  • Complications
    • Gas embolism is life threatening. With right ventricular outflow obstruction, expired end-tidal carbon dioxide falls, with concomitant hypotension and a “mill-wheel” heart murmur.
      • Insufflation is stopped and the pneumoperitoneum released.
      • The patient should be placed in a steep Trendelenburg position with the right side up to float the gas bubble up toward the right ventricular apex and away from the right ventricular outflow tract.
      • Air from the right ventricle is aspirated through a central venous catheter.

    • Brisk bleeding after trocar insertion warrants emergent conversion to open laparotomy. The trocar should not be removed until proximal and distal control of the injured vessel is achieved.

  • Alternatives to carbon dioxide pneumoperitoneum have been advocated because of the potentially deleterious effects of hypercapnia. Alternative pneumoperitoneum gases such as nitrous oxide, helium, and argon have been evaluated experimentally. Increased intra-abdominal pressure can occur with any insufflation gas (e.g., compression of the vena cava with decreased venous return to the heart, resultant hypotension, decreased renal blood flow, and diminished urinary output). External abdominal wall lift devices are available to create a working space without pneumoperitoneum.

D. Port placement
The location of ports has been standardized for most procedures, and several general rules for port placement have been established. All additional ports should be placed under direct video visualization. Prior to inserting the port, the surgeon indents the abdominal wall manually and identifies the location with the video camera. Transilluminating the abdominal wall identifies significant vessels to avoid. The skin and peritoneum are anesthetized locally. The surgeon makes a small stab incision with a no. 11 blade. The trocar is introduced in a direct line with the planned surgical target to minimize torque intraoperatively. The tip of the trocar should be visualized as it passes through the peritoneum.

  • The camera port should be behind and between the surgeon's two operative ports to maintain proper orientation.
  • Working ports are placed lateral to the viewing port, with the operative field ahead. All ports should be at least 8 cm apart to avoid the interference of instruments with one another. Ports should be approximately 15 cm from the operative field for the site to be reached comfortably by standard 30-cm instruments and to maintain a 1:1 ratio of hand-instrument tip movement.

E. Suturing and knot tying
Suturing and knot tying are essential skills for the surgeon to master before attempting advanced laparoscopic procedures. It is important to remember and anticipate suturing when considering port placement.
  • Extracorporeal knotting techniques are generally simpler to perform and are recommended for more durable tissues that can tolerate the pulling through of the excess suture material (e.g., the gastric wall or diaphragmatic crura). Extracorporeal techniques usually require more than 32 cm of suture and use a “knot pusher” to advance the throw down the port and make the knot snug. To avoid disruption, the knot pusher should be envisioned as an extension of the surgeon's finger while pushing the knot down to the tissue. Tension should be maintained on the other arm of the suture without pulling up on the tissue. An air leak occurs whenever suture is introduced or withdrawn through the introducer sheath. This can be reduced by having an assistant occlude the reducer orifice with a fingertip.
  • Loop ligatures provide preformed sliding knots on a thin stylet to allow rapid ligation of structures. A grasping instrument is placed through the loop and grasps the tissue or vessel. The loop is then closed and tightened around the pedicle.
  • Intracorporeal suturing is preferred for delicate tissues, such as the intestine, bile duct, or esophagus. Sutures should be 8 to 12 cm long. Laparoscopic instrument tying is similar to that of open surgery. A variety of specific techniques have been developed to accomplish knot tying. The surgeon should be facile with at least one technique and be able to tie a square knot without undue tissue trauma or time. The square knot is performed similarly to an instrument tie performed in open surgery.

F. Exiting the abdomen
The surgeon should survey the abdomen at the conclusion of the procedure to detect any visceral injury or hemorrhage. The operative site is irrigated, and hemostasis is obtained. Inspection of the peritoneal side of all port sites as the trocars are removed allows verification of hemostasis. Port-site fascial incisions that are larger than 5 mm should be closed with permanent or long-term absorbable suture to avoid the risk of incisional herniation. This can be done through the port-site incision or under video guidance with a fascial closure device (also known as a “suture passer”), which is particularly helpful in obese patients.
G. Converting to open surgery
A laparoscopic case may need to be converted to an open case for a number of reasons.

  • Elective conversion
    • Surgeon experience is critical. The surgeon's threshold for conversion should be low while gaining experience.
    • Failure to progress is the most common reason to convert. This can be secondary to adhesions, inflammatory changes, poor exposure, or altered or aberrant anatomy. In cases of unclear anatomy, avoiding injuries should take precedence over avoiding laparotomy.
    • The surgeon may discover a disease not appropriate for minimally invasive methods (e.g., gallbladder cancer or colon cancer invading adjacent organs).
    • Technical problems or instrument malfunction may occasionally require conversion. The surgeon must check that all equipment is in working order prior to starting the operation.

  • Emergent conversion should be performed in the event of severe bleeding or complex bowel injuries if repair is beyond the skill level of the surgeon.

H. Postoperative management
Postoperative management for most laparoscopic procedures is similar to that for open procedures, although laparoscopic surgery is associated with less postoperative pain and shorter hospital length of stay and recuperation time.

Submit "37 Common Surgical Procedures" to Digg Submit "37 Common Surgical Procedures" to del.icio.us Submit "37 Common Surgical Procedures" to StumbleUpon Submit "37 Common Surgical Procedures" to Google Submit "37 Common Surgical Procedures" to Facebook Submit "37 Common Surgical Procedures" to Twitter Submit "37 Common Surgical Procedures" to MySpace

Tags: None Sửa Tags
Chuyên mục
Washington M.of Surgery

Bình luận

# Đăng bình luận qua Facebook