What are the complications of post-operative hypotension and sedation?

From the Guidelines

Post-operative hypotension and sedation complications can lead to severe morbidity and mortality, and thus require prompt recognition and management to prevent organ hypoperfusion and respiratory depression. The most recent and highest quality study, 1, highlights that postoperative hypotension is often unrecognized and may be more important than intraoperative hypotension due to its prolonged nature. This study also identifies associations between postoperative hypotension and organ injury, especially acute kidney injury, cardiovascular events, readmission, and mortality.

Key Complications and Management

• Postoperative hypotension can lead to organ hypoperfusion, resulting in acute kidney injury, cardiovascular events, and increased mortality 1
• Sedation-related complications can cause respiratory depression, potentially progressing to respiratory arrest if not addressed promptly
• Management of postoperative hypotension involves assessing volume status and considering a fluid bolus of 500-1000mL crystalloid if the patient appears hypovolemic
• If hypotension persists, vasopressors such as norepinephrine or phenylephrine should be initiated
• For sedation-related complications, immediately reduce or discontinue the sedative agent and ensure adequate airway protection

Preventive Measures

• Careful titration of sedatives, especially in elderly or patients with renal/hepatic impairment
• Close monitoring of vital signs to promptly identify hypotension or sedation-related complications
• Avoiding unnecessary use of antihypertensive medications and ensuring adequate intravenous fluid administration to prevent hypotension

Evidence-Based Recommendations

The study 1 provides moderate-quality evidence that postoperative hypotension is associated with increased risk of adverse outcomes, and that harm thresholds appear to be an absolute systolic arterial pressure of 90-100 mm Hg or a mean arterial pressure of 60-75 mm Hg. Another study, 1, also highlights the importance of postoperative blood pressure management, recommending that patients with postoperative systolic arterial pressure <90 mm Hg should be closely monitored for potential harm. However, since 1 is the most recent and highest quality study, its findings take precedence in guiding clinical practice.

From the FDA Drug Label

The following adverse events have been associated with the use of naloxone hydrochloride injection in postoperative patients: hypotension, hypertension, ventricular tachycardia and fibrillation, dyspnea, pulmonary edema, and cardiac arrest. Death, coma, and encephalopathy have been reported as sequelae of these events Abrupt postoperative reversal of opioid depression may result in nausea, vomiting, sweating, tremulousness, tachycardia, increased blood pressure, seizures, ventricular tachycardia and fibrillation, pulmonary edema, and cardiac arrest which may result in death Excessive doses of naloxone in postoperative patients may result in significant reversal of analgesia and may cause agitation

The complications of post-operative hypotension and sedation include:

• Cardiac complications:
  • Ventricular tachycardia and fibrillation
  • Cardiac arrest
  • Pulmonary edema
• Neurological complications:
  • Seizures
  • Coma
  • Encephalopathy
• Other complications:
  • Nausea and vomiting
  • Sweating and tremulousness
  • Agitation 2 2

From the Research

Complications of Post-Operative Hypotension

• Post-operative hypotension can lead to organ injury, as intraoperative hypotension is associated with organ injury 3
• Hypotension can occur not only during surgery but also after surgery, and its incidence in post-anesthesia care units (PACU) is largely unknown 3
• The few episodes of PACU hypotension that do occur are typically short and of modest severity 3

Sedation and Hypotension

• Sedation can contribute to hypotension, and the combination of sedation and hypotension can have serious consequences, including decreased cerebral perfusion 4
• The use of inotropes and vasopressors to treat intraoperative hypotension can have different effects on cerebral hemodynamics, and some drugs may be more likely to preserve cerebral oxygen saturation than others 4

Management of Hypotension

• Fluid administration is a common technique used to prevent maternal hypotension, but the optimal fluid strategy has not been elucidated 5
• The use of colloids or crystalloids, as well as the timing of fluid administration, can affect the incidence of hypotension 5, 6
• Permissive hypotension, which involves keeping blood pressure low enough to avoid exacerbating uncontrolled hemorrhage while maintaining perfusion to vital end organs, may be a useful strategy in certain situations 7

Consequences of Untreated Hypotension

• Untreated hypotension can lead to serious consequences, including organ injury, decreased cerebral perfusion, and increased morbidity and mortality 3, 4, 7
• The global increased permeability syndrome (GIPS) may represent a third hit after the initial insult and the ischemia-reperfusion injury, and can lead to fluid overload and other complications 7