CHAPTER 4 Perioperative Care of the Thoracic Surgical Patient
PREOPERATIVE PREPARATION
An in-depth review of preoperative assessment is covered in Chapter 3. Medical optimization for thoracotomy patients includes adjustment of medications for chronic obstructive pulmonary disease (COPD), including administration of bronchodilators and steroids and treatment of acute bronchitis or pneumonia.1 Total resolution may not be possible if the pneumonia is caused by a postobstructive process secondary to lung mass or chronic aspiration from gastroesophageal reflux disease.
Patients with borderline pulmonary function benefit from pulmonary rehabilitation that increases their exercise tolerance and respiratory muscular strength before the resection.2 Preoperative pulmonary rehabilitation should be a routine component for all patients undergoing lung volume reduction surgery.3,4 Smoking cessation is of great importance. Support groups, counseling, nicotine replacement therapy, and Wellbutrin therapy are available and successful.5 If there is no smoking cessation program associated with the provider’s hospital, programs can be located by calling the local American Lung Association. Timing of smoking cessation before the operation remains debatable. Vaporciyan and colleagues showed that patients who quit smoking 4 weeks or more before surgery had a lower incidence of pulmonary complications than patients who continued to smoke or quit fewer than 4 weeks before pneumonectomy.6 Historically, 6 weeks of smoking cessation before surgery is recommended to avoid the copious bronchorrhea that accompanies regeneration of the cilia that clear mucus between 2 and 4 weeks after smoking cessation.7 However, Barrera and coworkers found no difference in the incidence of pulmonary complications between patients who were still smoking at the time of surgery and those who had quit fewer than 2 months before thoracotomy for lung resection.8 Our current recommendation is that all smokers requiring lung resection should be encouraged to quit smoking, and assisted to do so, at any time period before surgery.
Additional comorbid diseases that need to be managed include coronary artery disease, diabetes mellitus, and myasthenia gravis.1,9 The American Heart Association and the American College of Cardiology classify thoracic surgical procedures as medium risk. When there is no clinical history of risk factors for cardiac disease, no further workup is necessary if a preoperative 12-lead electrocardiogram (ECG) is normal.10 If a patient has risk factors for cardiac disease, further testing should be done to assess the presence and degree of disease. However, revascularization for significant coronary stenosis may not be preferable to medical therapy such as β-blocker administration for preventing perioperative cardiac events.11
Diabetic patients should have their cardiac, renal/intravascular volume, and glucose status checked before elective surgery.12 Electrolytes should be checked preoperatively and abnormalities treated. Baseline creatinine measurement is helpful. Acute elevation in creatinine needs to be investigated before elective thoracic surgery. Orthostatic vital signs should be also performed.
Diabetic patients optimally should have good glycemic control preoperatively. Long-acting sulfonylureas should be discontinued 48 to 72 hours before elective surgery. Shorter-acting sulfonylureas or secretagogues such as metformin can be stopped 12 hours before surgery. Long-acting insulin can be continued until the day of surgery if control has been good. If there is glucose level fluctuation, long-acting insulin should be stopped 24 to 48 hours before surgery, and sliding-scale insulin should be used with frequent glucose checks.12
For patients with myasthenia gravis, the goal of preoperative preparation is to reduce the risk of myasthenic crisis, which is acute respiratory muscle malfunction leading to respiratory failure. Dosages of steroids and anticholinesterase medication should be tailored to the patient’s symptoms. More aggressive and rapid therapies include infusion of intravenous immune globulin and plasmapheresis.9,13 Plasmapheresis usually requires multiple exchanges and is recommended for patients with a vital capacity of less than 2.0 L.
Prophylaxis
Atrial Fibrillation
The incidence of postoperative atrial fibrillation ranges between 3% and 30% in thoracic surgical patients.14 It increases the risk of stroke and prolongs postoperative length of stay, thus increasing hospital cost and mortality rate.14,15 The only consistent risk factor in surgical patients is age greater than 60 years.16 A retrospective review of over 2900 patients revealed increased relative risks of atrial fibrillation of 3.89, 7.16, 8.91, and 2.95 for lobectomy, bi-lobectomy, pneumonectomy, and esophagectomy, respectively, compared with a single wedge resection.14 Numerous studies on the prevention and treatment of postoperative atrial fibrillation have been done, but the majority were performed for cardiac surgical patients. There are currently no compelling data to recommend routine prophylaxis of atrial fibrillation in thoracic surgical patients.17 Meta-analysis shows that β-blocker, D-sotalol, and amiodarone are all effective in lowering the incidence of postoperative atrial fibrillation in cardiac surgical patients. Only amiodarone had a significant decrease in length of stay (by 0.9 days).18 However, there have been reports of acute pulmonary toxicity from amiodarone therapy in postoperative cardiothoracic surgery patients. No randomized trial has been done to study this phenomenon.19 Digoxin has been tried for prophylaxis but is not effective.17 Intravenous diltiazem was studied specifically in thoracic surgical patients and almost halved the incidence of postoperative atrial fibrillation (15% versus 25% for placebo patients).16 Studies of magnesium for prophylaxis and therapy of postoperative atrial fibrillation showed mixed results.17
Deep Venous Thrombosis
Postoperatively, a majority of thoracic surgery patients are slow to move because of pain, respiratory distress, and age. A review of multiple studies estimated a 10% to 30% incidence of deep venous thrombosis in patients in medical and surgical intensive care units.20 The current recommendations for deep venous thrombosis prophylaxis from the American College of Chest Physicians vary depending on patient risk (Box 4-1 and Table 4-1).21 Low-dose unfractionated heparin (LDUH) use does not interfere with epidural catheter placement or removal. However, low-molecular-weight heparin (LMWH) should be held for 12 to 24 hours before epidural placement or removal, to decrease the risk of hematoma formation. Use of LMWH for 2 to 3 weeks after hospital discharge in patients undergoing major cancer surgery may reduce the incidence of asymptomatic deep venous thrombosis.21
Box 4–1 Risk Factors for Venous Thromboembolism
Reprinted with permission from Geerts WH, Heit JA, Clagett GP, et al. Chest 2001;119(1 Suppl):132-75S.
Table 4–1 Levels of Thromboembolism Risk in Surgical Patients without Prophylaxis
| Level of risk | Successful prevention strategies |
|---|---|
| Low risk | No specific prophylaxis; early and aggressive mobilization |
| LDUH (5000 units q12h), LMWH (≤3400 U daily), GCS, or IPC | |
| LDUH (5000 U q8h), LMWH (>3400 U daily), or IPC | |
| LMWH (>3400 U daily), fondaparinux, oral vitamin K antagonists (INR, 2–3), or IPC/GCS + LDUH/LMWH |
GCS, graduated pneumatic compression stockings; INR, international normalized ratio; IPC, intermittent pneumatic compression; LDUH, low-dose unfractionated heparin; LMWH, low-molecular-weight heparin; VTE, venous thromboembolism.
Reprinted with permission from Geerts WH, Heit JA, Clagett GP, et al. Chest 2001;119(1 Suppl):132-75S.
Stress Ulceration and Gastritis
Stress ulceration prophylaxis is recommended in critically ill patients with coagulopathy, expected mechanical ventilation for longer than 48 hours, history of gastrointestinal bleeding or gastric ulceration in the past year, and at least two of the following: sepsis, intensive care unit stay of greater than 1 week, high-dose steroid administration, or occult bleeding lasting 6 or more days.22 The incidence of clinically significant bleeding remains low with use of pharmacologic agents for prophylaxis. Several strategies can be used for stress ulcer prophylaxis. Sucralfate decreases the risk of nosocomial pneumonia compared with the other agents.23 There is no intravenous formulation of sucralfate, so it can be given only to patients who can have oral or intragastric medications, and it must be given four times a day.22 There is an increased risk of aluminum toxicity if sucralfate is used for longer than 2 weeks in patients with renal insufficiency.24 Both histamine-2 (H2) blockers and proton pump inhibitors are effective in lowering gastric pH.25 H2 blockers interfere with the metabolism of medications that pass through the cytochrome P450 pathway, and dosages of other medications may need to be adjusted.26 Eating, or, if that is not possible, enteral feeding, is also helpful for prevention of stress ulcers postoperatively.
Infection
A properly timed dose of intravenous first-generation cephalosporin is efficacious in preventing wound infections from skin pathogens.27 For patients with β-lactam allergy, vancomycin or intravenous clindamycin are the substitutes of choice. Vancomycin administration must be started early enough to ensure that the dose is completely infused before incision is made. The prophylactic antibiotic is continued for one to two doses postoperatively. No data have supported the use of antibiotic beyond 24 hours for wound prophylaxis.
Prophylaxis for pneumonia and empyema in patients undergoing lung resection or esophageal resection is an attractive concept, as these involve clean-contaminated operative fields. Postoperative pneumonia was found in approximately 25% of patients undergoing lung resection in two different studies.28,29 Radu and colleagues demonstrated that only 18% of the pathogens postoperatively isolated from patients with pneumonia were susceptible to first-generation cephalosporin.28 They recommend consideration of use of prophylactic antibiotic to cover both gram-positive and gram-negative organisms.
Unfortunately, no clear data support this practice. The Surgical Care Improvement Project (SCIP)30 is a national program sponsored by the Center for Medicare and Medicaid Services along with other health organizations (American Hospital Association, Centers for Disease Control and Prevention) to decrease the number of surgical complications. Randomized trials showing an improved outcome with use of antibiotics effective on gram-negative organisms are needed for surgeons in the United States to justify their practice. SCIP participation delineates the timing of prophylactic antibiotic administration (within 1 hour of surgical incision), the type of antibiotic (first-generation cephalosporin with exceptions for medical reasons), and the duration of prophylactic antibiotic administration (limited to 24 hours or less for all surgeries except cardiac surgery; for cardiac surgery, 48 hours).
If a patient is receiving antibiotic for a therapeutic reason, prophylactic antibiotic use does not apply.30
Miscellaneous
Blood products are reserved for patients who have anemia because of preoperative chemotherapy, chronic disease, phlebotomy, or bleeding. Patients having elective major thoracic surgery should be given the option of autologous blood donation, which results in decreased risks of infection, transfusion reaction, and immune modulation, and increased cost effectiveness.31–33 Careful screening must be done to ensure there is no contraindication and there is adequate time to alleviate the iatrogenic anemia caused by autologous blood donation.31,32 Use of erythropoietic agents has been effective in eliminating or decreasing the amount of anemia in patients with cancer who have received chemotherapy or radiation therapy. Although preoperative or postoperative use of erythropoietin or darbepoetin is an attractive idea for thoracic oncology patients, no data exist to support this practice. In addition, there are reports of increased risk of deep venous thrombosis in oncology patients given erythropoietic agents for anemia.34
Warfarin therapy for patients with prosthetic heart valves should be stopped 72 hours before surgery, and intravenous unfractionated heparin should be started when the international normalized ratio (INR) is less than 2.0 for patients at high risk of thromboembolic incidents. Patients at high risk include those with mechanical heart valves in the mitral position and those with three of the following: atrial fibrillation, left ventricular dysfunction, previous thromboembolism, hypercoagulable condition, and mechanical prosthesis. For patients with prosthetic heart valves and low risk of thromboembolic incident, and for those with arrhythmia or low ejection fraction on anticoagulation, no bridge therapy is recommended.35
INTRAOPERATIVE CARE
Ventilation
Single-lung ventilation during thoracotomy or thoracoscopy is accomplished by placing a double-lumen tube, bronchial blocker, Univent tube, or, as a last resort, a single-lumen tube down the desired main-stem bronchus.36 Use of lower intraoperative tidal volumes during single-lung ventilation has been shown to decrease the incidence of respiratory failure in pneumonectomy patients.37 Increased peak inspiratory pressure, decreased oxygen saturation, and increased end-tidal CO2 during the procedure without a known etiology from the surgical field lead to a differential diagnosis of retained secretions or blood, dislodgement of the endotracheal tube or blocker, or contralateral pneumothorax. Stabilization may require reinflation of the operative-side lung if increased fraction of inspired O2 (FIO2) administration and oxygen flow and gentle bagging by the anesthesiologist do not improve the situation. Investigations and treatments include suctioning of obstructing blood or mucus, bronchoscopy and repositioning of single-lung ventilation equipment, or decompression of the contralateral pleural space of air.
Monitoring
Different operations require different levels of monitoring.1 ECG monitoring and continuous pulse oximetry are necessary in all cases. An arterial line is placed if there is a need for multiple blood samples. Continuous arterial pressure monitoring is useful during procedures involving mediastinal dissection, such as transhiatal esophagectomy, to gauge cardiac or great vessel compression. Temperature monitoring by bladder temperature probe or esophageal temperature probe is necessary for major procedures (see Body Temperature, next).
Body Temperature
Mild hypothermia has been shown to increase wound infection, blood loss and transfusion requirements, and cardiac events including ventricular tachycardia, cardiac arrest, and myocardial infarction.38 Heat loss through thoracotomy, sternotomy, and laparotomy incisions can be lessened by keeping the room temperature greater than 21° C, using airway heating and humidification devices, covering portions of the patient not in the operative field, and using forced-air warming blankets. Warm saline lavage intrapleurally and intraperitoneally can also be performed. Rarely are intravenous fluid warmers needed.
Positioning
Careful positioning of the patient is of utmost importance in the operating room. The surgeon needs to ensure adequate access for the planned operation as well as any potential counterincisions or chest wall resection. Use of muscle flaps often requires planning ahead to protect the vascular supply and leave adequate skin coverage. Padding to prevent neuropathy includes the use of an axillary roll for the decubitus position and padding of both arms. Stability of the patient during the operation can be achieved using a deflatable beanbag, sand bags, laminectomy rolls, and security straps or tapes. The lithotomy position also requires careful positioning to prevent postoperative neuropathy.39
Drainage
The viscosity of the substance being drained dictates the size and shape necessary for adequate drainage of the pleural space. Smaller anterior tubes are used to drain air. Larger posterior tubes, including preformed 90-degree-angle tubes, are useful for dependent drainage of blood, pus, chyle, or exudative fluid along the diaphragm. One pleural tube is adequate for drainage after routine lobar resection if it is positioned posterior to and to the apex of the pleural cavity to drain both fluid and air. If significant disruption of lung parenchyma is known or suspected, use of more than one pleural drainage tube is prudent to prevent formation of subcutaneous emphysema and improve the chance of pleural opposition.40 Additional chest tubes are used for empyema or hemothorax drainage or fistula drainage.
Specimen Management
The surgeon must also ensure that sample and specimen collection is done properly. Careful labeling and delivery of frozen sections are of paramount importance in determining resection margins, resectability, and staging. Intraoperative communication with the pathologist performing frozen section may be necessary before proceeding with the next portion of an operation. If possible, orienting the specimen and viewing the frozen section with the pathologist are recommended. A recent retrospective subset analysis of the data from the American College of Surgeons Oncology Group Z0060 trial of esophageal resection revealed that more accurate accounting and assignment of lymph node station occurs when surgeons separate and label lymph nodes for analysis than when the pathologist dissects, counts, and labels the nodes.41 Cultures for bacterial, fungal, and acid-fast bacilli need to be processed and collected in the correct specimen containers/mediums.
POSTOPERATIVE CARE
As in many other specialties, clinical pathways serve to improve the quality of care, and they have the added benefit of reducing cost.42 Almost all thoracic surgical patients can be transferred from the recovery room to a stepdown unit or surgical ward instead of to an intensive care unit. For thymectomy, segmentectomy, lobectomy, pneumonectomy, lung volume reduction, and esophagectomy patients, telemetry and continuous pulse oximetry are recommended. The arterial line placed during surgery is transduced until the day after surgery.
Fluid Management
Fluid administration for lung resection patients must be determined on an individual basis. Vasodilation secondary to use of local anesthetic in epidural catheters, and the use of antihypertensive medications justify careful administration of fluid to maintain blood pressure and adequate end-organ perfusion. In a review of published reports of postoperative pulmonary edema, Slinger found that multiple factors were probably contributors to the formation of the edema.43 The review gives guidelines regarding postoperative fluid management: (1) a maximum of 20 mL/kg fluid to be given intravenously for the first 24 postoperative hours, (2) acceptance of average urine output of 0.5 mL/kg/hr the first 24 hours, and (3) use of vasopressors if tissue perfusion is inadequate and the 20 mL/kg maximum of fluid has already been administered. Other manipulations such as lowering the dose of the epidural infusion or removing the local anesthetic component of the epidural infusion and leaving only narcotic may decrease sympathetic blockade and vascular vasodilation. There are no randomized trials that show a benefit of colloid administration versus crystalloid administration for fluid boluses.44
Blood Administration
No hemoglobin level or hematocrit has been documented as being a threshold for recommending transfusion. In critically ill patients with cardiovascular disease, a hemoglobin level of 7.0 to 9.0 g/dL is well tolerated.45 Although intuition argues that a higher hemoglobin level provides better oxygen delivery, the increased oxygen extraction by most organs and tissues when stressed negates the need for a higher hemoglobin level. This is not true for the heart, which extracts most of the oxygen delivered under nonstressed physiologic conditions and requires increases in blood flow to increase oxygen delivery with physiologic stress. For critically ill patients with acute cardiac ischemia, increased mortality was found with a restrictive transfusion protocol.46
Medications
Administration of postoperative antibiotics for more than 48 hours has not been definitively proven to decrease the amount of pneumonia or wound infection in thoracic surgical patients.47 SCIP (see Infection, earlier) protocol requires use of a first-generation cephalosporin (unless the patient is allergic) for 24 hours or less for wound prophylaxis. Treatment of known infection precludes following SCIP protocol.30
Many patients suffer from nausea after general anesthesia or postoperative pain medications. Antiemetics such as metoclopramide, ondansetron, promethazine, trimethobenzamide, and prochlorperazine can help. Stress ulcer prophylaxis is now recommended for high-risk surgical patients only (see Stress Ulceration and Gastritis, earlier).22 Esophagectomy patients have a high risk of reflux.48–50 H2-receptor blockers or proton pump inhibitors should be continued in patients who demonstrate reflux on barium swallow tests postoperatively, have symptoms of heartburn, or have a history of Barrett’s disease. Vagotomized patients may benefit from the prokinetic effects of erythromycin or metoclopramide. However, erythromycin may cause gastrointestinal upset and metoclopramide can produce extrapyramidal symptoms. Use of low-molecular-weight heparin, low-dose unfractionated heparin, or sequential compression devices continues until the patient is reliably walking at least four times a day for patients with a low risk for deep venous thrombosis. For higher-risk patients, a combination of pharmacologic and mechanical prophylaxis should be used until the same ambulatory criteria are met (see Box 4-1 and Table 4-1).21 The constipating effects of narcotic medications and decreased motility indicate the need for a bowel management protocol.
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