Enhanced Recovery Strategy- Principles, Practice and Implementation
Enhanced recovery After Surgery (ERAS) are multimodal perioperative care pathways designed to attenuate the stress response during the patients’ journey through a surgical procedure, facilitate the maintenance of preoperative bodily compositions and optimize organ function, and in doing so achieve early recovery. ERAS integrate a range of perioperative interventions to maintain physiologic function and facilitate postoperative recovery. Successful implementation of ERAS pathways requires collaboration between surgery, anesthesia, perioperative nursing to provide optimal perioperative care as well as having the support of hospital administration.
Anesthesiologists play a vital role in facilitating recovery because they routinely manage some of the key elements of ERAS. The key steps invovled, include:
preoperative assessment and patient education
perioperative fluid management
short acting anesthetic agents
optimal multimodal analgesia
prevention of postoperative nausea and vomiting (PONV)
prevention of other opioid related side effects
close monitoring during surgery
Nutritional Support in ERAS
As defined by the National Surgical Quality Improvement Program (NSQIP), malnutrition is among the few modifiable preoperative risk factors associated with poor surgical outcomes, including mortality, in surgical patients. Postoperative nutritional support is vital in maintaining nutritional status during the catabolic postoperative period and underscored by evidence for early and sustained feeding following surgery as part of ERP protocols.
The recommendations for perioperative nutrition may be summarised as:
The ideal analgesic regimen would provide effective pain relief, reduce opioid related side effects and surgical stress response and improve clinical outcome e.g. morbidity, mortality and hospital stay.
The concept of multimodal analgesia was introduced to achieve these goals by combining various analgesic techniques and different classes of drugs to improve postoperative outcome. It is prudent to attenuate postoperative pain as effectively as possible during the intraoperative period and initiating effective analgesic therapy in the early phase of perioperative period.
The effectiveness of individual analgesics is enhanced by the additive or synergistic effect of two or more drugs acting by different mechanisms.
Appropriate nerve blocks depending on the site of surgery are useful in providing short to intermediate-term pain relief after surgery. Direct visualization of neural tissue with ultrasound technology and the utility of stimulating catheters has made placement of indwelling catheters safer and more accurate.
Continuous infusion of local anesthetics through a peripheral nerve catheter is becoming increasingly popular in both hospital and ambulatory setting to achieve prolonged analgesia.
Management of PONV
Identification of patients at high risk for PONV enables targeting prophylaxis to those who will benefit most from it. Patient, anesthesia, and surgery related risk factors have been identified.
A number of PONV risk scoring systems have been developed. Apfel et al developed a simplified risk score consisting of four predictors: female gender, history of motion sickness or PONV, non-smoking status and the use of opioids for postoperative analgesia.
There are at least four major receptor systems involved in the etiology of PONV. Therefore, PONV can be achieved by the use of two or more antiemetics acting at different receptors compared with monotherapy. Antiemetics with different mechanisms of action have additive rather than synergistic effects on the incidence of PONV.
First, the risk of PONV should be estimated for each patient. For patients at moderate to high risk for PONV, regional anesthesia should be considered. If this is not possible or contraindicated and a general anesthetic is used, strategies to minimize the baseline risk of PONV should be adopted, e.g. minimize the use of opioids, avoid high dose neuromuscular reversal drugs and the use of propofol maintained anesthesia. Second, the use of combination antiemetic therapy and more appropriately a multimodal approach in high-risk patients is recommended.
Perioperative Fluid Management
Minimise NPO (Nil Per Oral) hours.
Clear carbohydrate containing liquids (preferably complex, e.g. maltodextrin) upto 2 hours before surgery.
If bowel preparation is performed, iso-osmotic agents are preferred.
The use of intraoperative goal-directed fluid therapy (GDFT) is likely to be safe in the majority of patients undergoing major colorectal surgery. GDFT has little risk and the use of advanced hemodynamic monitoring equipment may enhance clinical decision-making when compared with the use of conventional monitors.
Advanced hemodynamic monitoring equipment to be used to guide clinical decision- making intraoperatively be selected based on a combination of surgical, patient and institutional factors since such monitoring can minimize both hypovolemia (by promoting therapy in volume responders) and hypervolemia (by restricting therapy in non-responders).
The fluid management strategies focus on:
Identifying if there is a clinical problem that can be solved by fluid therapy
Identifying what fluid and how much is appropriate
Rather than treating every instance of abnormal hemodynamic values
(displayed by conventional or advanced monitors), clinicians must establish causation based on available information about the patient and clinical context.
ERAS recommend the use of buffered isotonic crystalloids for the treatment of hypovolemia in patients undergoing colorectal surgical procedures.
Patients tolerating fluids orally after surgery may be given unrestricted access to such fluids, as this increases patient satisfaction and as it is likely that intravenous fluid administration offer no added benefit.
In summary, enhanced recovery is the cornerstone for reducing hospital length of stay, reducing postoperative complications and potentially increase patient satisfaction. Many successful enhanced recovery program has been shown to increase quality and reduce cost, thereby increase value of healthcare delivery. Enhanced Recovery will likely become standard of care in the near future and should be embraced by patients, surgeons, anesthesiologists, hospital administrators, medical insurance payers and governments alike.