RT Book, Section A1 Butterworth IV, John F. A1 Mackey, David C. A1 Wasnick, John D. SR Print(0) ID 1161433970 T1 Postanesthesia Care T2 Morgan & Mikhail's Clinical Anesthesiology, 6e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259834424 LK accessmedicine.mhmedical.com/content.aspx?aid=1161433970 RD 2024/03/28 AB 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 responsive, pain is often 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 also be considered in the differential diagnosis of postoperative restlessness or agitation. Postoperative nausea and vomiting (PONV; see Chapter 17) is the most common significant complication following general anesthesia, occurring in approximately 30% or more of all patients. Intense shivering causes precipitous rises in oxygen consumption, CO2 production, and cardiac output. These physiological effects may be poorly tolerated by patients with cardiac 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 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 inadequate fluid replacement, wound draining, or hemorrhage. Noxious stimulation from incisional pain, endotracheal intubation, bladder distention, or preoperative discontinuation of antihypertensive medication is usually responsible for postoperative hypertension.