We applaud Drs. Sessler and Jarkas for advocating for a “fourth branch of anaesthesia: intense postoperative management” in the May ASA Monitor (ASA Monitor 2024;88:15-7). Advancements such as wearable monitoring technology, artificial intelligence-based risk prediction, and early warning scoring systems will identify patients at risk of deterioration; however, these technologies are only as effective as the responding effector limb. We wish to offer one scalable solution.

Building on the vision of Drs. Sessler and Jarkas, we advocate for the creation of specialized bundles of perioperative care to deliver preemptive and responsive interventional strategies (e.g., treating hypotension and hypoxia). Enhanced care units, led by anesthesiologists or intensivists, offer a scalable solution that can be stand-alone, co-located with postanesthesia care units, or housed in surgical wards. Enhanced care units, also called advanced recovery room care units, bridge the gap between dichotomous surgical ward-level care and high-dependency and intensive care units by offering level 1 to 1.5 care. For reference, high-dependency units offer level 2 care, and intensive care units offer level 3 care (asamonitor.pub/4cknkAJ; asamonitor.pub/4fEpmPc). Enhanced care units allow for continuous monitoring, goal-directed hemodynamic therapy, and the ability to intervene with intravenous vasopressor support (e.g., norepinephrine infusions) or noninvasive ventilatory support outside of critical care settings.

Enhanced care units offer a proactive multidisciplinary care ethos and excel in managing intermediate- to high-risk patients during the “golden” 24-48 hours postoperatively. The focus is generally on enhancing short-term postoperative management (asamonitor.pub/4cknkAJ; asamonitor.pub/4fEpmPc).

Salient features of enhanced care units include:

  1. Continuous postoperative monitoring of vital signs via invasive or wireless technologies
  2. Access to advanced monitoring capabilities, including advanced hemodynamic monitoring and cardiac and lung ultrasound
  3. Provision of advanced treatment techniques tailored to individual patients’ pathophysiology, including vasopressor medication, high-flow oxygen therapy, noninvasive ventilation, and regular access to multidisciplinary respiratory services, including physical therapy
  4. Preservation of enhanced recovery after surgery (ERAS) principles (e.g., DrEaMing; Drinking, Eating, Mobilisation) (World J Surg 2019;43:659-95; Br J Anaesth 2022;129:114-26).

Evidence from small studies supports that elective postoperative admission of intermediate- to high-risk patients to enhanced care units decreased medical emergency responses required on surgical wards, reduced rates of complications, hospital length of stay, hospital readmission, and offered consequent economic benefits to hospital services (J Clin Med 2024;13:534; JAMA Surg 2023;158:701-8; Anaesthesia 2021;76:480-8; Br J Anaesth 2017;118:100-4; Value Health 2022;25:215-21).

Swart et al. reported that intermediate-risk (predicted 30-day postoperative mortality 1%-3%) patients electively admitted to higher-acuity environments undergoing general surgery had fewer emergency laparotomies after their index procedure (0% vs. 10% p=0.005), fewer unplanned critical care admissions (0% vs. 16% p=0.0001), and attributable cost savings in this group (Br J Anaesth 2017;118:100-4). Ludbrook et al., reported that a care bundle delivered in an advanced recovery room care unit increased days at home within 30 days after surgery (DAH-30: 15 days vs. 17; p=0.04), reduced the frequency of medical emergency response-level events postoperatively, and subsequently reported associated health-economic benefits compared to usual ward care (JAMA Surg 2023;158:701-8; Anaesthesia 2021;76:480-8; Value Health 2022;25:215-21). Koning et al. compared an enhanced care unit to a mixed-case high-dependency unit and reported improvements in hospital length of stay (J Clin Med 2024;13:534).

When enhanced care units are available, there is little evidence suggesting additional benefit from admission to more resource-intensive admission to high–dependency and intensive care units (Br J Anaesth 2017;118:123-31; Anesth Analg 2019;128:533-42). The detrimental effect of a reactive model of care is illustrated by one study reporting that indirect (delayed) admission to a high-dependency or intensive care unit compared to elective postoperative admission was associated with more than double the risk of mortality (adjusted OR 2.39, 95%CI 2.01-2.84) (Br J Anaesth 2017;118:123-31).

“Enhanced care units offer a proactive multidisciplinary care ethos and excel in managing intermediate- to high-risk patients during the ‘golden’ 24-48 hours postoperatively. The focus is generally on enhancing short-term postoperative management.”

In summary, we fully agree with Drs. Sessler and Jarkas that anesthesiologists can significantly impact the “hidden pandemic” of postoperative morbidity and mortality by leveraging AI-generated risk prediction and wearable technology for continuous postoperative monitoring. However, scalable access to appropriate and timely effector limb therapy is necessary. This therapy should focus on bundles of care, including “low dose” hemodynamic and respiratory support during the “golden hours” after surgery. Enhanced care units offer a vital resource that bridges the gap between ward-based care and high-dependency and intensive care, providing a scalable solution for intermediate- to high-risk patients who are often treated on traditional surgical wards due to limited access to high-dependency and intensive care units. This approach may significantly improve postoperative outcomes.