Enhanced Recovery After Surgery: Protocol and Goal-Directed Fluid Therapy

Introduction

• Initially conceptualized in the 1990s by Professor Henrik Kehlet of the University of Copenhagen, Denmark, ERAS is a multimodal, multidisciplinary approach to patient care throughout the perioperative period.¹
• It was first implemented for colonic surgeries and later expanded to various other surgical procedures with the creation of the ERAS Society, a nonprofit organization whose mission is to optimize perioperative care and accelerate post-operative recovery through research, education, and the implementation of evidence-based practice.¹
• By using a multimodal approach to perioperative care, ERAS guidelines aim to alleviate surgical stress and preserve organ function during the patient’s hospital stay.²
• ERAS protocols have improved perioperative morbidity and mortality, reduced length of stay, and decreased operative complications. An anesthesiologist plays a critical role as they optimize patients preoperatively, monitor them intraoperatively, and deliver care in the postoperative period.²

Protocol

• The ERAS protocol is not a one-size-fits-all approach, and there are specialty-specific guidelines that address procedure- or specialty-relevant nuances in the perioperative period. A general outline of the ERAS protocol is listed below that is applicable to a majority of the current guidelines. The protocol is organized into preoperative, intraoperative, and postoperative components.

Preoperative Period

• Patient education and counseling:
  • Preoperative information received by the patient allows the physician and patient to engage in shared decision-making. It helps the patients form expectations of the procedure and promotes higher patient satisfaction.⁴
  • Key elements of this step include discussing what is likely to occur in the perioperative period and the criteria for patient discharge.
• Preadmission risk stratification:
  • This is important so the patient and multidisciplinary team know what to expect in terms of recovery.
  • There is a wide variety of risk-scoring systems used to group patients on a scale from low to high risk.
  • Some examples include the Physiological and Operative Severity Scoring for the enUmeration of Mortality and morbidity scoring system (POSSUM), the Lee index for risk of perioperative cardiac events, and the well-known American Society of Anesthesiologists physical status score.³
• Preadmission optimization of pre-existing health conditions or patient risk factors:
  • Patient comorbidities such as cardiovascular disease, chronic lung diseases, anemia, etc., should be managed and well-controlled prior to the procedure.^2-5
  • Risk factors such as smoking and alcohol use should be stopped at least 4 weeks prior to surgery, as it has been shown that cessation for this amount of time can decrease perioperative complications.^3,4
• Nutritional optimization:
  • Patients should fast prior to their operation; current studies show that they can safely have clear liquids up to 2 hours before and solid food up to 6 hours before.^2-4
  • It has also been noted that carbohydrate loading with complex carbohydrates the night before and a few hours before surgery can help decrease insulin resistance and the catabolic state induced by prolonged fasting and surgery.^2-4
  • This is important as insulin resistance leads to increased stress hyperglycemia, impaired immunity, and an exaggerated inflammatory response, all of which may contribute to increased complications.
• Preanesthetic medication plan:
  • Preoperative pain and anxiety are common predictors of how a patient’s postoperative pain will be. With this in mind, it is appropriate for the physician to consider short-acting anxiolytics and analgesic medications (preferably non-opioid to minimize the amount of opioids used) pre-induction.^3-5

Intraoperative Period

• Standardized, multimodal anesthetic approach:
  • Depending on the surgery at hand, the anesthesiologist will tailor a general anesthesia plan to minimize the impact of agents and techniques on organ function and facilitate easy awakening from anesthesia.³
  • The use of regional techniques (e.g., epidural anesthesia, regional blocks, etc.) and neuromuscular blocking agents can be determined at the end of the preoperative period or at this stage.^2-4
• Depth of anesthesia monitoring:
  • The goal is to avoid patient awareness intraoperatively while avoiding unnecessary use of anesthetic agents.³
  • Traditionally, depth has been monitored by clinical observation of the patient; however, we now have additional measures to aid in assessment. The bispectral index uses an electroencephalogram to monitor patients’ brain activity during anesthesia. Also used to monitor depth are minimum alveolar concentration equivalents, which apply to the inhaled anesthetics.³
• Intraoperative hemodynamic management:
  • One of the key elements of hemodynamic management is the use of intravenous fluids. The goal is to maintain euvolemia,^2-4 with studies showing that balanced crystalloid fluids are preferred over normal saline.³
  • When evidence of hypovolemia or hypotension is present, GDFT is implemented to guide fluid administration by utilizing hemodynamic indicators.³
  • When fluid therapy alone fails to improve the patient’s hemodynamics, vasopressors may be used.
• Prevention of postoperative nausea and vomiting (PONV):
  • This is one of the most significant adverse events for patients undergoing anesthesia.²
  • Multiple factors influence PONV, with some of the most common being predisposing risk factors (female gender, history of motion sickness or PONV, etc.), the use of inhaled anesthetics (especially nitrous oxide), and opioid use.^2-4
  • It is common practice to administer an antiemetic agent and steroids to prophylactically treat PONV; if PONV persists despite initial prophylaxis, it is advisable to add an additional antiemetic from a different class.^3,4
• Prevention of hypothermia:
  • Intraoperative hypothermia is associated with increased cardiac events, blood loss, surgical site infections (SSIs), and delayed wound healing. For any procedure lasting longer than 30 minutes, it is important to use warming devices to maintain normothermia.^2-4
• Surgical technique:
  • Recommendations for surgical techniques vary by surgical specialty. Minimally invasive approaches are commonly favored, though this is not true in every specialty.^3-5
  • It is important that the surgical technique be decided on a case-by-case basis, with multiple factors considered, including the surgical goals, available technology, and the surgeon’s experience.⁴
• Surgical site infection prophylaxis:
  • For every surgical procedure, sterile technique, including proper patient preparation and sterile personal protective equipment for the surgical team, is used to ensure a sterile surgical field and minimize the risk of infection.^2,4
  • Administration of a broad-spectrum antibiotic with coverage for Staphylococcus aureus is also recommended to decrease the risk of infection.⁴

Postoperative Period

• Multimodal pain control:
  • The multimodal pain regimen in the postoperative period is designed to minimize opioid use.
  • The mainstay medications consist of nonsteroidal anti-inflammatory drugs, acetaminophen, gabapentinoids, and COX-2 inhibitors unless there is a contraindication to use in the patient.^2-4
  • Regional anesthesia (e.g., epidural blocks, intrathecal morphine, peripheral nerve blocks, etc.) may also be used in the postoperative period and has aided in decreased opioid use.^3,4
• Early mobilization:
  • The goal is to reduce complications associated with prolonged bed rest, such as muscle atrophy, increased risk of thromboembolism, and reduced pulmonary function.^3,4 This may include exercises in bed, sitting at the edge of the bed, standing, or ambulation. Daily activity goals should be set to encourage and track progress.³
• Early oral intake/feeding:
  • Patients should resume their normal diet within 24 hours of their procedure. This has been shown to improve insulin resistance (and thus decrease the complications mentioned above in the preoperative section), allow early cessation of intravenous fluids, and improve gut motility, which decreases the incidence of postoperative ileus.^2-4
• Early removal of drains and indwelling catheters:
  • Drains and urinary catheters increase the risk of infection as well as prevent early mobilization in some cases. As early as clinically indicated, these should be removed from the patient to promote recovery.^2-5
• Thromboembolic prophylaxis:
  • Virtually all hospitals already have a thromboprophylaxis protocol, and that protocol should be incorporated into their ERAS protocol. Depending on the patient, thromboprophylaxis can be mechanical or chemical.^2,4,5
• Audit and improvement:
  • All ERAS programs should have a formalized audit to identify common pitfalls and determine which protocols need to be updated. This will help increase ERAS program compliance and encourage quality improvement.^2,4,5

GDFT

• GDFT is a perioperative fluid management strategy that uses hemodynamic monitoring to guide fluid administration, tailored to each patient’s physiologic needs rather than relying on a preset volume goal. The main overarching goal of perioperative fluid management is to maintain a central euvolemic state, which may decrease complications. Perioperative fluid management is a critical element of ERAS protocols across every surgical specialty.⁶
• Key parameters used for hemodynamic monitoring in GDFT consist of dynamic measures such as stroke volume variation (SVV) and cardiac index (CI), while also using more static measures like mean arterial pressure (MAP) and central venous pressure.^6,7
• By monitoring these parameters, GDFT aims to optimize tissue perfusion and oxygen delivery while avoiding the harmful effects of over-resuscitation with intravenous fluids.⁶

• A recent study looked at GDFT in patients receiving major abdominal surgery, where patients with an SVV greater than 12% for over 5 minutes were given a 250 mL crystalloid bolus, and if the SVV was still greater than 12% or had decreased by over 10%, a 250 mL colloid bolus was given. A minimum CI of 2.5 L/min/m² and MAP greater than 65 mmHg were required. If a patient had a CI below this goal, they received inotropes and if MAP was below goal, they received vasopressor support.⁷
• The study found shorter length of stay and faster recovery of gastrointestinal function in the GDFT group compared with the control group.⁷