What are the preoperative, intraoperative, and postoperative considerations for patients classified as American Society of Anesthesiologists (ASA) III undergoing procedures?

Perioperative Management of ASA III Patients

Patients classified as ASA III require comprehensive perioperative management due to their severe systemic disease with substantive functional limitations, necessitating specific preoperative optimization, careful intraoperative management, and vigilant postoperative monitoring to minimize complications and mortality. 1

Understanding ASA III Classification

• ASA III patients have severe systemic disease with substantive functional limitations, including conditions such as poorly controlled diabetes or hypertension, COPD, active hepatitis, alcohol dependence, implanted pacemaker, moderate reduction of ejection fraction, and morbid obesity (BMI ≥40 kg/m²) 1
• ASA III patients represent approximately 80% of vascular surgery patients, making this a critical category for perioperative risk assessment 2
• Functional capacity assessment is an integral part of preoperative evaluation and can help further stratify risk within ASA III patients 2

Preoperative Considerations

• Thorough preoperative evaluation is essential to identify specific risk factors and optimize the patient's condition before surgery 1
• Preoperative initiation of continuous positive airway pressure (CPAP) should be considered for patients with obstructive sleep apnea (OSA), particularly if severe 3
• For patients who do not respond adequately to CPAP, invasive positive pressure ventilation should be considered 3
• Preoperative use of mandibular advancement devices or oral appliances and preoperative weight loss should be considered when feasible 3
• Patients with known or suspected OSA may have difficult airways and should be managed according to difficult airway guidelines 3
• For patients with severe aortic stenosis (AS), preoperative evaluation to exclude severe coronary artery disease with CT or angiographic imaging may be useful 3

Intraoperative Management

• Consider the potential for postoperative respiratory compromise when selecting intraoperative medications, especially in patients with OSA who are susceptible to respiratory depressant effects 3
• For superficial procedures, consider local anesthesia or peripheral nerve blocks, with or without moderate sedation 3
• If moderate sedation is used, ventilation should be continuously monitored by capnography due to increased risk of undetected airway obstruction 3
• General anesthesia with a secure airway is preferable to deep sedation without a secure airway, particularly for procedures that may mechanically compromise the airway 3
• Major conduction anesthesia (spinal/epidural) should be considered for peripheral procedures 3
• For patients with severe AS, maintain sinus rhythm and normotension; phenylephrine or norepinephrine can be used to increase blood pressure in patients without significant coronary artery disease 3
• For patients with mitral stenosis, maintain left ventricular preload and sinus rhythm, with careful intravenous fluid administration to avoid increases in left atrial pressure 3

Postoperative Management

• Unless contraindicated, patients at increased perioperative risk should be extubated while awake 3
• Full reversal of neuromuscular block should be verified before extubation 3
• When possible, extubation and recovery should be carried out in the lateral, semiupright, or other nonsupine position 3
• Hospitalized patients at increased risk of respiratory compromise should have continuous pulse oximetry monitoring after discharge from the recovery room 3
• Continuous monitoring may be provided in a critical care or stepdown unit, by telemetry on a hospital ward, or by a dedicated, appropriately trained professional observer 3
• Continuous monitoring should be maintained as long as patients remain at increased risk 3
• If frequent or severe airway obstruction or hypoxemia occurs during postoperative monitoring, initiation of nasal CPAP or noninvasive positive pressure ventilation should be considered 3
• ASA III patients, particularly those with OSA, require oxygen provision during transport from the operation site to the recovery ward to prevent arterial oxygen desaturation 4

Risk Stratification Within ASA III

• ASA III patients can be further subdivided based on functional capacity measured in metabolic equivalents (METs), with <4 METs (IIIA) or ≥4 METs (IIIB) 2
• This subclassification has demonstrated significant differences in outcomes, with ASA IIIB patients showing higher rates of myocardial infarction and death compared to ASA IIIA patients 2
• Functional status (independent vs. dependent) is another important factor, with functionally dependent ASA III patients (IIIB) showing a 5-fold increase in mortality compared to independent patients (IIIA) 5
• ASA III patients with independent functional status can be treated safely in day surgery settings with proper pre-assessment and preparation 6

Special Considerations for High-Risk Procedures

• For ASA III patients undergoing high-risk procedures, the 90-day mortality rate can be significantly higher compared to ASA I-II patients (7.6% vs. 3.2%) 7
• Independent predictors for major complications in ASA III patients include previous abdominal operations and elevated body mass index 7
• For patients with severe AS and normal left ventricular ejection fraction, noncardiac surgery can be performed with acceptable risk by optimizing loading conditions and avoiding hypotension and tachycardia 3
• Periprocedural hemodynamic monitoring with a right-heart catheter or intraoperative transesophageal echocardiography may be particularly useful for continuous optimization of loading conditions in patients with valvular heart disease 3