I. GENERAL CONSIDERATIONS

Patients who undergo thoracic surgery require close monitoring during the perioperative period and frequently spend the first postoperative night in the postanesthesia care unit (PACU) or surgical intensive care unit (SICU). Close attention must be paid to their respiratory, cardiac, fluid, and electrolyte status, because they are at risk for respiratory decompensation and cardiac arrhythmias that can result in significant morbidity and mortality if not recognized and treated early. In most institutions, patients who typically go to the SICU directly from the operating room for postoperative recovery include those who have undergone tracheal resection and reconstruction, esophagectomy, pulmonary decortication, or pneumonectomy. Most patients undergoing subtotal lung resection, including wedge resection, segmentectomy, or lobectomy, usually recover overnight in the PACU, which provides an increased level of care, and then transfer to the surgical floor on the first postoperative day. As such, these patients will be the focus of the remainder of this chapter.

II. PREOPERATIVE TESTING

Many patients undergoing pulmonary resection have multiple underlying comorbidities that increase their risk for complicated postoperative recovery, including chronic obstructive pulmonary disease (COPD), smoking, coronary artery disease, diabetes mellitus, and advanced age. Prior to surgery, it is essential that these patients undergo complete cardiac and pulmonary evaluation in order to develop appropriate anesthetic, operative, and recovery plans that are designed to minimize individual morbidity and mortality. Preoperative workup usually includes EKG, as well as echocardiogram and cardiac stress testing if there is history of coronary artery disease, heart failure, or other cardiac symptoms. Pulmonary function tests (PFTs) are routinely performed to predict postoperative residual respiratory capacity and dictate goals for recovery. PFTs are particularly important in patients undergoing pulmonary resection and contribute to determining the surgical approach. Often, routine PFTs are supplemented with ventilation/perfusion scanning and exercise testing in particularly marginal patients.

Some data support that smoking cessation is best achieved 4 to 6 weeks prior to surgery in order to avoid a paradoxical increase in tracheobronchial secretions, which is thought to be caused by the regeneration of cilia that aid with mucous clearance. However, more recent studies have not found an optimal time frame for preoperative smoking cessation, but rather confirm that active smokers have a higher risk of pulmonary morbidity and mortality than those patients who had quit smoking preoperatively. It is therefore generally recommended that all patients attempt to quit smoking preoperatively, regardless of the time to surgery.

III. ANALGESIA

Adequate analgesia is critical to the postoperative recovery of lung function because inadequate pain control promotes atelectasis, mucous
plugging, and inability to clear secretions, resulting in the development of life-threatening pneumonia. Most patients undergoing thoracotomy will have an epidural catheter placed preoperatively and receive a combination of local anesthetic and narcotic analgesia (most commonly 0.1% bupivacaine with 20 µg/mL hydromorphone or 2 µg/mL fentanyl) administered through both a continuous rate and a patient-controlled demand dose. In addition to improved pain control, thoracic epidural analgesia has been shown to improve clinical outcomes by reducing pulmonary morbidity, including atelectasis, hypoxia, and pneumonia, as well as reduce the rate of reintubation and the duration of mechanical ventilation if needed.

Although epidural analgesia is generally very well tolerated, the more common adverse reactions include pruritus, urinary retention, nausea, emesis, sedation, respiratory depression, and hypotension. High thoracic epidurals generally should not cause lower extremity weakness. If a patient does experience lower extremity weakness or tingling, the epidural infusion should be temporarily discontinued and leg strength assessed every 30 minutes. If the weakness does not improve, the anesthesia team must be immediately contacted due to concern for possible development of epidural hematoma or abscess. Pruritus will often improve with administration of antihistamines, but if persistent, can be treated by switching to an alternate opioid medication, administering the opioid agonist-antagonist nalbuphine hydrochloride, or removing the opioid entirely from the epidural infusion. Hypotension and sedation usually improve with decreasing the rate of epidural infusion, although it is not uncommon for patients to require low-dose vasopressor agents, usually phenylephrine, during the first 12 to 24 hours postoperatively. Urinary retention is prevented by placement of a urinary drainage catheter intraoperatively, which remains in place until the epidural catheter is removed. Epidural catheters are usually kept in place until removal of all thoracostomy tubes, or up to 5 days postoperatively.

Alternatives to epidural analgesia include paravertebral or intercostal nerve blocks or systemic opioid administration via patient-controlled administration (PCA) pumps. Patients who have undergone video-assisted thoracoscopic surgery (VATS) as opposed to open thoracotomy most commonly receive postoperative analgesia through PCA pump rather than epidural catheter. Nonsteroidal anti-inflammatory drugs such as ketorolac can also be given as an adjunct to opioids at doses of 15 to 30 mg every 6 hours if there is no concern for bleeding or renal insufficiency. Early and effective pain control is critical to improve pulmonary mechanics, minimize atelectasis, and allow for early patient mobilization, all of which have been shown to decrease morbidity, mortality, and length of hospital stay following pulmonary resection.

IV. PULMONARY TOILET AND EARLY AMBULATION

Promoting lung reexpansion and improving respiratory mechanics are critical during the postoperative period to prevent respiratory failure and pneumonia. Incentive spirometry should be taught early and encouraged regularly to minimize atelectasis. Chest physiotherapy, encouraging cough and deep breathing, and vibrational therapy can also assist with early mobilization and clearance of secretions. Early ambulation should be encouraged, and all patients should be walking by the first postoperative day. If possible, patients should be mobilized from bed to chair the night of surgery. Consultation with physical therapy is often helpful to assist with early mobilization and to assess discharge needs. In patients at risk for bronchospasm, scheduled nebulizer treatments with saline or bronchodilators, such as albuterol and ipratropium, can help promote deep breathing and air exchange. If there is concern for airway edema, steroids
or racemic epinephrine nebulizer treatments can also be administered. If there is continued difficulty mobilizing thick or copious secretions, nasotracheal suctioning can be performed at the bedside or in the recovery room by an experienced provider. Early evaluation by respiratory therapists can be very effective for secretion management. Chest x-ray should be performed immediately postoperatively in the PACU, as well as daily throughout the postoperative course, in order to monitor lung reexpansion and to evaluate for pneumothorax, effusion, mucous plugging, or the development of pulmonary edema or pneumonia. If there is concern for declining respiratory status or increased secretions, workup should include arterial blood gas, chest x-ray, nebulizer treatments, evaluation by the respiratory therapist, and an immediate call to the thoracic surgeon or surgery team. Bedside bronchoscopy is sometimes required to assist with pulmonary toilet and remove inspissated mucous from the central airways.

V. FLUID BALANCE

In general, most patients undergoing pulmonary resection are kept with an even to minimally positive fluid balance in order to minimize postoperative pulmonary edema. Maintenance fluids are administered at a rate of 1 to 2 cc/kg/hour, with goal total fluid balance of no more than 1.5 L positive (20 cc/kg/day) during the initial 24 hours postoperatively. Almost all patients have a urinary catheter placed intraoperatively, and urine output is monitored closely within the first 24 hours postoperatively, with goal urine output roughly 0.5 cc/kg/hour. If urine output is adequate and there is no epidural in place, the urinary catheter is usually removed on the morning of the first postoperative day.

If hypotension is present, the patient should be assessed immediately for possible hemorrhage. Evaluation of the volume and character of the chest tube output, chest x-ray, and urine output is critical to determining whether a patient might be bleeding postoperatively. Output of over 200 cc of bloody fluid from the chest tubes for two consecutive hours often warrants return to the operating room for reexploration. If bleeding is suspected, complete blood count and coagulation studies (partial thromboplastin time, prothrombin time/international normalized ratio) should be followed, and blood products given as needed. If bleeding does not appear to be the cause of hypotension, and hypovolemia is still suspected, gentle fluid resuscitation may be undertaken. Fluid boluses should be low volume to prevent subsequent fluid overload and postoperative pulmonary edema, usually given as 250 cc boluses of normal saline or 5% albumin. If hypovolemia is not suspected to be the primary cause of hypotension, and the blood pressure does not improve with gentle fluid boluses and reduction of the epidural infusion rate (if present), patients may require temporary blood pressure support with vasopressors such as phenylephrine to ensure adequate tissue perfusion. In general, use of low-dose phenylephrine is preferred over excessive fluid administration in patients with postoperative low vascular tone. Maintaining an even to only slightly positive fluid balance minimizes postoperative lung injury, acute respiratory distress syndrome (ARDS), and pulmonary edema, as well as the development of postoperative atrial fibrillation (AF). On the night of surgery, oral intake is usually limited to clear liquids only, either as sips or ad lib. If the respiratory status is stable, diet advancement to a regular diet occurs on the first postoperative day, and intravenous fluids are discontinued as soon as oral intake is sufficient.