Postoperative Complications with Monitored Anesthesia Care

Postoperative Complications of Patients Undergoing Monitored Anesthesia Care

Introduction

Monitored anesthesia care (MAC) is commonly used for various surgical and diagnostic procedures, including endoscopies, minor orthopedic surgeries, and certain types of interventional radiology procedures. The goal of this intervention is to provide a comfortable and safe experience for the patient while allowing the healthcare team to perform the necessary, sometimes invasive procedures. The level of sedation can vary, ranging from minimal (light sedation) to moderate (conscious sedation) depending on the requirements of the procedure and patients’ individual needs. The purpose of this literature review is to develop the findings needed to articulate a comprehensive PICOT question that can serve as the foundation for a capstone project change proposal, addressing the clinical problem associated with postoperative complications in patients who have received MAC.

A comparison of research questions

The research questions in the first two studies (numbers correspond to evaluation table numbering) reviewed examined optimal sedation dosing during MAC for varicose vein stripping surgery to avoid respiratory depression and compare surgical outcomes for sialendoscopy with MAC versus general anesthesia. The third and fourth questions investigated whether MAC has comparable rates of postoperative complications and mortality to general anesthesia for transcatheter aortic valve replacement surgery, and whether adding a supraglottic airway to MAC can achieve similar procedural efficiency and adverse events as standard MAC without an airway device. Additional research questions introduced other aspects of MAC.

The fifth study’s research question focused on using a respiratory volume monitor to improve safety for patients getting gastrointestinal endoscopies with MAC. By contrast, the sixth study’s research question compared deep sedation MAC to general anesthesia for atrial septal defect closure surgery in terms of outcomes and complications. The penultimate study’s research question investigated whether administering dexmedetomidine during MAC or general anesthesia affects post-anesthesia care unit length of stay for ambulatory surgery patients. Finally, the eighth focuses on when providers should convert MAC to general anesthesia when sedation causes airway instability.

While the specifics of these studies varied, all of the research questions ultimately aim to clarify the optimal approach for airway/breathing management, sedation dosing, monitoring, and conversion to general anesthesia in order to maximize the safety and efficacy of MAC across different procedures. The research questions also sought to determine how MAC compares to general anesthesia for many surgeries regarding complications, mortality, recovery times, procedural efficiency, and other important outcomes.

A comparison of sample populations

The sample populations come from academic hospitals, medical centers, and surgical databases across the United States. The first study utilized hospital data on transcatheter aortic valve replacement (TAVR) procedures from the American College of Surgeons National Surgical Quality Improvement Program registry. The second study was conducted at an academic hospital among 51 patients getting varicose vein stripping surgery with MAC. The third study took place at Thomas Jefferson University including 172 patients who had sialendoscopic surgery with either MAC or general anesthesia.

The fourth study, performed at a tertiary academic medical center, matched 148 patients who got transcatheter femoral-transapical valve replacement surgery with a supraglottic airway to 148 who had the surgery with standard MAC. The fifth study enrolled 65 patients at the University of Texas Medical Branch undergoing upper and lower gastrointestinal endoscopies using total intravenous anesthesia for MAC. The sixth study retrospectively analyzed records from the Asan Medical Center in Korea for 311 patients who had atrial septal defect closure surgery with either deep sedation MAC or general anesthesia. Notably, the seventh study leveraged data on over 130,000 adult ambulatory surgery patients at Beth Israel Deaconess Medical Center to investigate associations between dexmedetomidine and recovery times. Finally, the eighth study examined over 219,000 cases at Mount Sinai Hospital in New York City when providers had to rescue patients’ airways by converting from initial MAC to general anesthesia due to sedation-related instability.

All of these studies focused exclusively on adult patient populations undergoing surgical or invasive medical procedures ranging from minimally invasive endoscopies to more complex surgeries like transcatheter valve replacement and atrial septal defect closure. Many studies emphasize ambulatory surgery populations or procedures commonly performed with MAC, highlighting the relevance of MAC for shorter outpatient surgeries. While sample sizes range considerably, many studies incorporate hundreds or even over a hundred thousand patients to generate sufficient statistical power for their analyses of relatively uncommon outcomes like postoperative complications. Together, the population samples reflect substantial data-driven efforts to clarify best clinical practices for optimizing patient safety and clinical outcomes with MAC.

A comparison of the limitations of the study

The analyses in the selected studies rely heavily on retrospective data, which can introduce biases and confounders that prospective randomized controlled trials would minimize. Appropriate statistical techniques were used to control variables between comparison groups, but residual confounding is still possible. Likewise, most of the findings lacked long-term follow-up, with outcomes limited to the perioperative period and 30 days postoperatively. Consequently, longer follow-up could help identify the respective advantages of one anesthesia approach over another that short-term data misses.

In some cases, comparatively small sample sizes may limit the generalizability of results and predispose some analyses to type II errors failing to detect true differences between groups when effects are subtle. Larger multi-center trials could improve statistical power and external validity. In addition, and perhaps most importantly, the criterion for converting MAC to general anesthesia was not standardized and left to clinical judgment, introducing subjectivity and variability. Therefore, more objective, protocolized criteria could facilitate comparisons between groups.

It is also important to note that self-reported measures like patient satisfaction and some complications (nausea, pain) have inherent subjectivity vulnerable to placebo effects. Blinded outcome assessors would optimize objectivity. Finally, the single-center nature for most studies means findings may not apply to other settings with variable provider experience, monitoring capabilities, and patient factors; multi-center designs enhance result reproducibility and improve the trustworthiness of the findings that emerge from these types of studies.

Conclusion and recommendations for further research

The findings that emerged from the comparison of the eight studies selected for these analyses identified a number of commonalities and differences in study design, sampling and analytical strategies, but with the common focus on optimizing patient safety and clinical outcomes using MAC. Despite the value of this and other previous research in this area, additional studies using high-quality randomized trials, expanded follow-up periods, larger multi-center samples, blinded outcome adjudication, and standardized management protocols could help provide valuable evidence to guide MAC utilization and improve patient outcomes.

References

Abbett, S.K., Urman, R.D., Resor, C.D., & Brovman, E.Y. (2021, February). The effect of anesthesia type on outcomes in patients undergoing transcatheter aortic valve replacement. J Cardiothorac Vasc Anesth, 35(2), 429-435.