Incidence

• Unknown; poorly studied in the population of patients undergoing general anesthesia.
• RV failure occurs in ~30% of patients after left ventricular assist device placement (LVAD).

Prevalence

Greater in patients with underlying pulmonary disease that contributes to chronic hypoxic states

• Cor pulmonale and pulmonary hypertension (PH) are associated with a 13.1-fold increase in perioperative morbidity and mortality when undergoing noncardiac surgery compared to cross-matched patients without PH (1).
  • More likely to develop congestive heart failure (OR = 11.9)
  • Susceptible to more hemodynamic instability and respiratory failure
  • Patients were shown to need longer ventilator support, stay longer in the intensive care unit (ICU), and have higher readmission to the hospital within 30 days of surgery.

• Despite equivalently smooth operative courses, PH patients had increased in-hospital deaths compared to matched controls (9.7% vs 0%); systolic pulmonary artery pressure (PAP) served as an independent predictor of mortality (2).
• These patients also had significantly more frequent postoperative heart failure and delayed extubation.

History

• Dyspnea and tachypnea often overlap with underlying pulmonary disease.
• Severity of underlying disease: Exercise tolerance, need for bronchodilators, or supplemental oxygen
• Exacerbations: Fatigue, worsening dyspnea, and increased oxygen requirements

Signs/Physical Exam

• Cardiac examination: A right-heave may be palpated along the left sternal border or in the epigastrium; an augmented pulmonic component of the second heart sound; and associated murmurs due to incompetence of the tricuspid valve (during systole) and/or pulmonic valve exist (during diastole). Both murmurs are augmented by inspiration.
• Peripheral edema, jugular venous engorgement, and positive hepatojugular reflex

Labs/Studies

• Arterial blood gas: Objectively assess the degree of respiratory insufficiency.
• Liver function tests: Dysfunction and coexisting coagulopathy
• EKG: Findings include RV enlargement, ventricular septal flattening "D-sign," ventricular dysmotility, and evidence of elevated estimated RV systolic pressure.
• Chest x-ray: A decrease in the retrosternal space on lateral films indicates RV hypertrophy. A prominent main pulmonary artery and decreased vascular markings may be consistent with PH.
• Echocardiogram: Right atrial and RV hypertrophy (peaked P waves in leads II, III, and aVF). Right axis deviation and right bundle branch blocks can also be seen.
• Pulmonary function tests: Assess the response to bronchodilator therapy.
• Right atrial pressure tracing: Predominant A wave due to enhanced right atrial contraction with decreased ventricular compliance.
• Right heart catheterization: Elevated PAP with normal pulmonary artery occlusion pressures (representing normal left ventricular end-diastolic pressure, LVEDP).
• Cardiac MRI: While not widely available, can provide accurate information on RV function.

• Maintaining oxygenation and ventilation is imperative; thus, medications that may depress ventilation (i.e., opioids) should be used judiciously.
• Inhaled beta-agonists may be needed to optimize pulmonary disease.

Increased risk of perioperative complications, morbidity, and mortality

• Dependent on the procedure. As a sole technique, regional anesthesia has the benefit of avoiding anesthetic induction, airway instrumentation, mechanical ventilation, and extubation, as well as minimizing systemic opioids. However, supplemental sedation, failed blocks, or complications of the block (e.g., high spinal and local anesthetic toxicity) need to also be considered. Additionally, patients may not be able to lie flat during a procedure.
• Supplementing the general anesthetic with a regional technique has the benefit of decreasing the need for systemic opioids.
• Caution should be exercised when performing regional techniques that can affect respiratory parameters. Interscalene blocks can cause phrenic nerve palsies (C3, C4, C5); neuraxial techniques to the T6 level can affect accessory muscles of respiration.

• Standard ASA monitors
• Invasive monitoring is dependent on the degree of patient dysfunction and the operative procedure.
• Arterial line. Monitoring arterial line BP helps identify rapid changes in hemodynamics and allows frequent blood gas measurements of PaO₂ and PaCO₂ (can aid with decision to extubate).
• Central lines can assess RV pressures.
• Pulmonary artery catheters. May be used to assess the degree of patient illness, effect of fluid shifts and changes in acid/base status from hypercarbia, laparoscopy, etc. by monitoring the PAPs.
• An alternative to invasive monitoring includes transesophageal echocardiogram; however, this monitor requires expertise and is usually employed only while the patient is intubated

• To minimize increases in PVR, patients should have an adequate depth of anesthesia prior to instrumenting the airway.
• Supraglottic devices (i.e., LMA) may decrease airway stimulation; however, adequate ventilation must be ensured to prevent respiratory acidosis.
• The RV can also be preload dependent against the fixed afterload of PH. Anesthetic selection must avoid sympathetic spikes without dropping systemic vascular resistance.

• N₂O is controversial with conflicting evidence on its effects on PVR. Monitoring the right atrial or PAP can allow early identification of intolerance and allow discontinuation.
• Neuromuscular blockade (and other anesthetic drugs) should avoid histamine release.
• Fluids should be titrated judiciously; patients can be sensitive to hypovolemia and require a sufficient preload to maintain the RV output. However, hypervolemia can overload the Frank–Starling curve of the RV and lead to strain or failure and worsening venous congestion.

• Extubation. Standard criteria apply; however, patients may be less capable of meeting them. If adequate ventilation and oxygenation cannot be ensured, consider delaying extubation. Deep extubation can result in inadequate ventilation and hypercarbia.
• A smooth emergence with minimal coughing is desired to prevent increased intrathoracic pressure, RV afterload, and sympathetic input.
• Tracheal application of lidocaine may be helpful to minimize the response to airway instrumentation.