The most frequent complication in the PACU is airway obstruction. Common causes include:

A clinical sign of partial obstruction is sonorous respiration. A sign of complete obstruction is absent breath sounds and often paradoxical movement of the chest with respiration.

Treatment modalities include supplemental oxygen, head lift, jaw thrust, oral or nasal airway, or reintubation. If the patient displays signs of extrinsic compression of trachea, such as an expanding hematoma with airway compromise, reopening of the wound and drainage is therapeutic and can be lifesaving.

Laryngospasm (uncontrolled contraction of the laryngeal cords) may also be seen in the PACU. Clinical indicators may include a high-pitched crowing or silence if the glottis is totally closed. This may be more common after airway trauma, repeated airway instrumentation or with copious secretions (including blood or vomit in airway). Management includes positive pressure mask ventilation, oral or nasal airway, suctioning, small dose of succinylcholine if refractory, intubation, and finally cricothyroidotomy or jet ventilation if the inability to intubate or ventilate is encountered.

Common causes of hypoventilation in the PACU are residual depressant effects of anesthetics (most common), residual neuromuscular blockade, splinting from pain, diaphragmatic dysfunction after thoracic or upper abdominal surgery, distended abdomen, tight abdominal dressings, and increased CO₂ production (e.g. shivering, sepsis, and hypothermia). The clinical signs may include prolonged somnolence, slow respiratory rate, shallow breathing with tachypnea, and labored breathing. The signs may not become prominent until the PaCO₂ >60 or pH <7.25. Treating the underlying cause is the mainstay of therapy, but until that is accomplished, control of ventilation is essential. Intubation may be necessary (hemodynamically unstable, severely obtunded, etc.). Provide an opioid antagonist (naloxone in increments of 0.04 mg IV) if an opioid overdose is a possibility, administer a cholinesterase inhibitor if residual paralysis is suspected. If the patient is splinting, consider increasing pain control measures depending on respiratory rate and mental status.

Common causes of hypoxemia in the postoperative setting are increased intrapulmonary shunting due to decreased FRC (most common), pneumothorax, prolonged ventilation with small tidal volumes, endobronchial intubation, bronchial obstruction by blood or secretions leading to collapse, aspiration, bronchospasm, pulmonary edema, and atelectasis. The early signs usually involve restlessness, tachycardia, and ventricular or atrial dysrhythmias. The late signs usually include hypotension, obtundation, bradycardia, and cardiac arrest. The treatment generally includes supplemental O₂, and the patient may need a nonrebreather mask. If symptoms persist, the patient may need intubation until the underlying cause is found and corrected. A chest x-ray should be ordered immediately. Treatment obviously depends on the underlying cause. A chest tube should be placed if a pneumothorax or hemothorax is discovered and bronchodilators (e.g. albuterol) given if bronchospasm is suspected. Consider administering diuretics if there is fluid overload, and performing a bronchoscopy if there is severe atelectasis due to obstructive plugs or aspiration.

The most common causes of hemodynamic compromise in the recovery unit can be differentiated into problems associated with preload, left and right ventricular function, and afterload. Hypotension can result from one or more of these causes, as outlined in Table 28.2.

The clinical signs of hypotension include a 20–30 % baseline decrease in blood pressure, disorientation, nausea, change in consciousness, decreased urine output, and angina. Treatment of hemodynamic compromise should include fluid bolus, vasopressor agents, pleural aspiration if tension pneumothorax is suspected, pericardiocentesis if a cardiac tamponade is suspected, and invasive monitoring (arterial line, CVP, or PA catheter) if necessary. The treatment depends on the patient’s clinical picture and underlying cause.

Postoperative hypertension is a frequent occurrence in the PACU. Common causes include noxious stimuli (most common), incisional pain, irritation from the endotracheal tube, distended bladder, previous history of hypertension, fluid overload, metabolic derangements (hypoxemia, hypercapnia, and acidosis), and intracranial hypertension. Clinical signs and symptoms include headache, bleeding, vision changes, angina, and ST changes on ECG. Treatment includes correcting the underlying problem, draining the bladder, providing analgesia, and correcting metabolic derangements. Be aware of the patient’s baseline preoperative blood pressure, and use that as a target for titration. Specific medical therapies other than analgesia are listed in Table 28.3 below.

Postoperative tachycardia is often mediated by parasympathetic output or caused by medications such as atropine, glycopyrrolate, and muscle relaxants (e.g. pancuronium). See Table 28.4 for differential diagnosis of tachycardia. Signs and symptoms may include hypertension or hypotension and angina. Treatment includes treating the underlying cause, fluid bolus, draining the bladder, and pain control. Symptomatic treatment may be necessary to allow offending medications to wear off. Cardiac arrhythmias are also common causes of tachycardia. If atrial fibrillation occurs, consider beta blockade, calcium channel blockers, and potentially cardioversion if the patient becomes hemodynamically unstable.