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KEY CONCEPTS
Patients emerging from anesthesia should not leave the operating room until they have a patent airway, have adequate ventilation and oxygenation, and are hemodynamically stable. Qualified anesthesia personnel must attend the transfer to the postanesthesia care unit (PACU).
Before the recovering patient is fully awake, pain may be manifested as postoperative restlessness or agitation. Significant systemic disturbances (eg, hypoxemia, respiratory or metabolic acidosis, hypotension), bladder distention, or a surgical complication (eg, occult intraabdominal hemorrhage) must be considered in the differential diagnosis of postoperative restlessness or agitation.
Postoperative nausea and vomiting (PONV; see Chapter 17) is the most common immediate complication following general anesthesia, occurring in approximately 30% or more of all patients.
Intense shivering causes precipitous rises in oxygen consumption, carbon dioxide (CO2) production, and cardiac output, which may be poorly tolerated by patients with cardiac and/or pulmonary impairment.
Respiratory problems are the most frequently encountered serious complications in the PACU. The overwhelming majority are related to airway obstruction, hypoventilation, hypoxemia, or a combination of these problems.
Hypoventilation in the PACU is most commonly due to the residual depressant effects of anesthetic and analgesic agents on respiratory drive, often made worse by preexisting obstructive sleep apnea.
Hypoventilation with obtundation, circulatory depression, and severe acidosis (arterial blood pH <7.15) is an indication for immediate and decisive ventilatory and hemodynamic intervention, including airway and inotropic support as needed.
Following naloxone administration, patients should be observed closely for recurrence of opioid-induced respiratory depression (“renarcotization”), as naloxone has a shorter duration of action than many opioids.
Increased intrapulmonary shunting from a decreased functional residual capacity relative to closing capacity is the most common cause of hypoxemia following general anesthesia.
The possibility of a postoperative pneumothorax should always be considered following central line placement, supraclavicular or intercostal blocks, abdominal or chest trauma (including rib fractures), neck dissection, thyroidectomy (especially if thyroid dissection extends into the thorax), tracheostomy, nephrectomy, or other retroperitoneal or intraabdominal procedures (including laparoscopy), especially if the diaphragm may have been penetrated or disrupted.
Hypovolemia is the most common cause of hypotension in the PACU and can result from hemorrhage, wound drainage, or inadequate fluid replacement.
Noxious stimulation from incisional pain, endotracheal intubation, bladder distention, or preoperative discontinuation of antihypertensive medication is usually responsible for postoperative hypertension.
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Historically, the routine expectation of specialized postanesthesia nursing care was prompted by the recognition that many preventable deaths occurred immediately following anesthesia and surgery. The World War II experience of providing surgical care to battle casualties contributed to the postwar trend for centralized recovery rooms, where skilled nurses could closely and simultaneously attend several postoperative patients. Recently, some postoperative patients are more frequently cared for overnight in a postanesthesia care unit (PACU), or the equivalent, when there is a shortage of surgical intensive care beds.
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Another recent change in postanesthesia care is related to the shift from inpatient to outpatient surgery. Now, more than 70% ...