Ambulatory Anesthesia

Introduction

• Ambulatory anesthesia enables same-day discharge from surgical and diagnostic procedures.
• The rapid expansion of ambulatory surgery—now representing over 70% of surgical procedures in some countries—reflects advances in surgical techniques, anesthetic drugs, and perioperative care models.¹
• Benefits of ambulatory surgeries include:
  • For patients: more efficient scheduling of surgery, convenience of recovering at home, lower costs due to avoidance of a hospital stay, and lower facility fees.²
  • For facilities: reduced staffing and overnight care costs, enhanced turnover rates, low complication rates, and avoidance of unplanned admissions.¹
• Successful implementation depends on appropriate patient selection, optimization of patient comorbidities, facility preparedness, and adherence to evidence-based protocols to maintain safety and efficiency.¹

Patient and Procedure Selection

• Careful patient selection is critical to optimizing safety and reducing unplanned admissions (Figure 1).
  • American Society of Anesthesiologists (ASA) Physical Status:
  • ASA I–II patients are generally appropriate for ambulatory surgery.
  • ASA III patients may be considered if comorbidities are stable and optimized.
  • ASA IV patients are typically not suitable unless the procedure is minor, anesthesia is minimal, and resources are available for escalation.
  • Social Support: a responsible adult escort and home support for 24 hours post-procedure is mandatory.
• Careful selection of procedures and the type of anesthesia can facilitate early ambulation and effective pain control.²
  • Minimally invasive procedures with low expected blood loss and pain are ideal.
  • Surgeries with major fluid shifts, significant postoperative pain, or high risk of complications are less appropriate.¹

Anesthetic Considerations

Preoperative Considerations

• Patients should undergo comprehensive screening for obstructive sleep apnea (OSA), diabetes, cardiac risk factors, and airway difficulty, which may be conducted via questionnaire or over the telephone.
• Defer surgery if chronic diseases are not optimized due to acute exacerbations or unstable control.
• Patients are educated on fasting, medication adjustments, pain control, and discharge criteria.³

Intraoperative Considerations

• Premedication with prophylactic oral analgesia can be a great use of multimodal analgesia that improves analgesic levels in the early postoperative period.¹
• The most common risk of general anesthesia resulting in prolonged postanesthesia care unit (PACU) stays is PONV. Ambulatory patients should receive prophylactic antiemetics.¹
• Use short-acting anesthetics and multimodal analgesia to facilitate rapid recovery and reduce opioid-related respiratory depression.
• Spinal anesthesia can be useful for lower extremity procedures, but must be tailored to avoid residual motor/sympathetic block leading to delayed discharge.⁴
• Regional anesthesia can facilitate recovery by reducing postoperative pain and can minimize the need for opioid analgesics.⁴
• The use of regional anesthesia is associated with higher patient satisfaction and greater overall efficiency in the ambulatory setting.³

Postoperative Considerations

• Common ambulatory criteria include being awake with stable vital signs, minimal pain, and minimal nausea.
  • Patients may be discharged from Phase 1 to Phase 2 of recovery when they are awake and oriented, normothermic, and able to maintain their own airway and oxygen saturation without supplemental oxygen.¹
• With the increased use of short-acting drugs and techniques, many patients can go directly to the phase 2 unit; this is known as fast-track recovery. The modified Aldrete score can be used to assess eligibility for the fast-track program.^1,5
• Proceed with standard discharge if the case is uneventful in malignant hyperthermia-susceptible patients.

Considerations for Special Patient Populations

Patients with Diabetes

• A comprehensive preoperative assessment should include review of HgbA1C, medication regimen, and documentation of any diabetes-related comorbidities or complications.⁶
• Home medications and glycemic control should be optimized prior to the ambulatory care setting to reduce the risk of infection, poor wound healing, and surgical outcomes.
• Maintaining blood glucose within target ranges is recommended, with an emphasis on avoiding hypoglycemia.
• Resumption of patients’ home medication regimens should be carefully coordinated with the care team, with emphasis on resumption of baseline regimens promptly in the PACU.²

Geriatric Patients

• Preoperative assessment of frailty is essential.
• Delirium-causing agents should be avoided or used cautiously, including meperidine, anticholinergics, benzodiazepines, and opioids.
• Postoperative cognitive dysfunction (POCD) is common among the elderly. Careful monitoring for POCD is warranted when caring for geriatric patients in an ambulatory setting.²

Patients with OSA

• The Society for Ambulatory Anesthesia (SAMBA) recommends the STOP-Bang criteria for preoperative screening for OSA.⁷
• Patients with a history of OSA have an increased risk of respiratory complications.
• Promotion of opioid-sparing, multimodal analgesia and regional anesthesia is recommended.
• Heightened vigilance, use of positive airway devices, and avoidance of long-acting opioids are recommended in patients with OSA in the PACU.
• More stringent criteria for patient selection for the ambulatory setting and PACU discharge should be employed to ensure safety.⁸

Contraindications for Ambulatory Anesthesia

Absolute Contraindications

• Lack of responsible postoperative care at home.
• ASA IV–V with unstable disease.
• Inability to obtain informed consent.
• Need for postoperative intensive care unit or prolonged monitoring.¹

Relative Contraindications

• Poorly controlled comorbidities.
• Severe untreated OSA with anticipated opioid use.
• Comorbidities or patient care that requires lab monitoring.
• History of anesthetic complications requiring prolonged postoperative care.
• Airway procedures in patients with a predicted difficult airway and limited rescue capabilities.
• Procedures with a risk of large blood loss.¹

Standards and Guidelines

• Facilities should be accredited by recognized bodies and adhere to national standards.
  • Immediate availability of resuscitation equipment, malignant hypothermia (MH) cart with dantrolene, and trained staff is required.
  • Transfer agreements with nearby hospitals capable of managing emergencies are essential.⁵
• Here are key professional society guidelines and recommendations for anesthesia care in the ambulatory setting:
  • SAMBA consensus statements on diabetes management, pediatric tonsillectomy, and MH susceptibility.
  • ASA guidelines for patient selection and perioperative management in ambulatory settings.
  • AAGBI & CPOC are UK-based recommendations emphasizing safety checklists and post-discharge support.
• Anesthesia Patient Safety Foundation highlights the importance of facility readiness, emergency preparedness, and anesthesia professional vigilance in all settings.