Author: Michael Vlessides
Anesthesiology News
A retrospective study at a rural community hospital has found a low incidence of airway complications when anesthesiologist-based teams administer sedation during gastrointestinal procedures. Nevertheless, their complication rate was markedly higher than that reported by nonanesthesiologists who perform similar procedures at other institutions, prompting the investigators to question why such discrepancies exist.
According to Yvon F. Bryan, MD, an associate professor of anesthesiology at Wake Forest Baptist Health, in Winston-Salem, N.C., various medical specialists commonly use deep sedation and/or general anesthesia, particularly with propofol, in patients undergoing colonoscopies. Given the recent switch to anesthesiology-based teams providing such care at a rural hospital affiliated with their institution, the investigators sought to determine the nature and frequency of airway complications by anesthesiology-based teams in this setting.
With that in mind, the investigators reviewed the charts of 94 adult patients (47 women; mean age, 60.4 years) undergoing colonoscopies at Lexington Medical Center, part of Wake Forest Baptist Health, between September 2015 and June 2017. Seven different endoscopists performed the colonoscopies, and anesthetic technique was at the discretion of the anesthesia provider.
Most patients (85/94; 90.4%) received only propofol; the remaining nine received propofol with an adjunct, including midazolam (n=4), ketamine (n=3) or midazolam plus ketamine (n=2). The mean propofol dose was 118.9±43.7 mcg/kg per minute. The mean length of anesthesia time was 35.3±15.4 minutes, while the mean procedure time was 23.6±11.0 minutes.
The analysis revealed that seven of the 94 patients (7.4%) experienced moderate desaturations, with one (1.1%) experiencing a severe desaturation. Only one of the patients required placement of an oral airway to assist with ventilation; none were intubated.
Factors Affecting Complications Disparity
“Overall, we found a low incidence of airway complications with this anesthesia-based team in a rural setting,” Johnson said. “But our incidence of desaturation was higher than that reported by nonanesthesiologist teams in similar environments, who report anywhere from 0.5% and 2.0% [Clin Endosc 2017;50(2):161-169; Gastroenterology 2016;150(4):888-894].”
This, the investigators explained, may have been due to several factors, including higher levels of ASA III and IV patients seen in the study (42/94; 44.7%), the selection of healthier patients by non–anesthesiologist-based teams, and studies being performed in large medical and specialized academic centers.
“Our desaturation rates also may have been higher because anesthesiologist-based teams are typically involved in more complicated cases,” Johnson added.
“Do you have data from before the anesthesia team arrived?” asked session moderator Michael Russell, MD, an assistant professor of anesthesiology at West Virginia University, in Morgantown.
“Prior to the arrival of anesthesiology-based teams at the institution, sedation was administered by nurses and physicians who had a wide variety of different techniques, and there had never been any studies performed,” Dr. Bryan said. “Therefore, nobody could tell us what the previous incidence of desaturation was.”
The researchers went performed another similar analysis, this time on patients undergoing esophagogastroduodenoscopy (EGD) under anesthesiology-based team care at the rural institution (abstract PS172). “EGDs are more stimulating to a patient and may require a deeper level of sedation or general anesthesia than colonoscopies,” said Douglas McLaughlin, BS, a research assistant in anesthesiology at the institution. “What’s more, these patients may be more complicated, with higher ASA status.” EGDs also may predispose patients to increased risk for aspiration and airway complications due to esophageal and/or gastric diseases.
The researchers studied the records of 91 adult patients undergoing the procedures at the institution, finding that 10 patients (11%) desaturated: Six had moderate desaturations, while the remaining four had severe desaturations. Four patients (4.4%) were intubated, although all were planned due to emergent EGD for food bolus and/or bleeding. The mean propofol dose was 111.5±59.8 mcg/kg per minute.
“As with colonoscopies, we compared our desaturation rate in these patients with that in the GI literature,” McLaughlin said. “And while studies in the literature [Saudi J Gastroenterol2017;23(3):133-143] report rates as low as 0.01% in these individuals, we obviously did not find that.
“Now we’re developing a prospective study and want to develop a technique to drive down our incidence of desaturations and airway complications, to hopefully make it safer for patients getting these procedures done,” he added.
“Once again this is a brave study with brave conclusions,” Dr. Russell said. “Do you know if the low rates quoted in the GI literature have some sort of qualifier built into it, such as a duration qualifier? I find it almost impossible to believe that they have desaturation rates of 0.01%.”
“They did not do a time analysis on the duration of the desaturations,” McLaughlin replied.
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