Modified Laryngeal Mask Designed to Circumvent Adverse Events from Upper GI Procedures

Upper gastrointestinal endoscopic procedures may be commonplace, but they have surprisingly high complication and mortality rates. The advent of a modified laryngeal mask that can simultaneously protect the airway and facilitate the passage of an endoscope may reduce some of these adverse events.


Modified Laryngeal Mask Designed to Circumvent Adverse Events from Upper GI Procedures. Photo courtesy of Marcus Skinner, MBBS

Preliminary results from an Australian study found that the mask facilitated endoscopic insertion with no failures and no airway compromise after device removal.

“GI endoscopy is now one of the most commonly performed medical procedures under sedation and anesthesia,” said Marcus Skinner, MBBS, FANZCA, clinical associate professor of anaesthesia at the Royal Hobart Hospital, in Hobart, Australia.

Upper Endoscopies Ubiquitous

“In the U.S. alone, more than [6.9] million upper endoscopies, 11.5 million lower endoscopies and 200,000 biliary endoscopies are performed annually.” Although such procedures may be widely perceived as low risk and routine, published data tell another story. For instance, an analysis by H.M. Park, et al (Medicine 2015;94:e1934) examined the clinical characteristics and mortality of life-threatening events requiring cardiopulmonary resuscitation in 263,000 endoscopies.

“They found that among cases with an adverse event, 2% were in upper GI endoscopies, 57% were nonemergent procedures and, surprisingly, 32% were in ASA [American Society of Anesthesiologists] I and II patients,” Dr. Skinner said. “They also quoted a mortality rate of 1.5 per 10,000, which is significantly higher than the overall all-cause anesthetic mortality rate, which is somewhere in the order of one in 55,000.

“So we have an issue,” he added. “I believe the adverse events associated with this procedure—particularly upper endoscopic procedures—are underreported and significantly higher than typically appreciated. So clearly, there’s a need for enhanced patient safety.”

To that end, Dr. Skinner and his colleagues developed the LMA Gastro Airway (Teleflex), which features a dedicated endoscopic channel that facilitates esophageal entry of the endoscope, plus a separate airway channel with a cuff that allows airway protection, patient oxygenation and ventilation with end-tidal carbon dioxide monitoring. After initial development—made with CT scanning to confirm anatomic alignment—the device was successfully tested on fresh cadavers, demonstrating that endoscopy was readily achievable while maintaining a supraglottic mask seal during positive-pressure ventilation.

To help determine the efficacy of the novel device, the researchers enrolled 300 ASA physical status class I and II patients into the single-arm, prospective observational study, all of whom were undergoing upper GI endoscopy and were at low risk for gastric aspiration. All participants underwent a standardized total intravenous anesthetic and standardized insertion of the device.

Reporting results from the first 80 participants at the ASA 2016 annual meeting (abstract A3022), Dr. Skinner noted that the mean age of patients was 52.6 years (77.5% men), and they had a mean body mass index of 27.6 kg/m2. Almost one-fourth (23.8%) had a history of respiratory disease, 8.8% had a history of cardiovascular disease, and 10% had diabetes that was treated.

Learning Curve

It was found that all of the endoscopic insertions were performed successfully, with no failures. What’s more, only one patient required a second attempt at inserting the endoscope through the device. There was one instance of airway device failure after insertion, although it was not associated with airway compromise, and the procedure was completed without complication. There were no instances of airway compromise after device removal.

The first-attempt success rate at placing the LMA Gastro was 86%. “There is a learning curve with this device,” Dr. Skinner noted, “but if we compare that with data of LMA first-attempt insertion success rates in published data, it ranges from 77% to 98%. So the LMA Gastro is midway between those two.”

The investigators also analyzed outcome data after removal of the device, finding a 0.6% airway compromise rate. “We found blood on the device in 19% of patients,” Dr. Skinner said. “We are still subanalyzing this process, but it seems the majority of these patients underwent some form of esophageal biopsy.”

The study also yielded a sore throat rate of 33.5%. “This seemed reasonably high, until we reviewed the literature and found that the reported incidence of sore throat after LMA use varies widely.

“I believe we can perform endoscopies more safely,” Dr. Skinner concluded. “I had problems in the 2000s when we used classic laryngeal masks and put the endoscope behind them: Although it worked, it was very untidy. These outcomes are very promising, and suggest that the LMA Gastro will meet the rigorous statistical proof necessary for clinical acceptance of the device. I eagerly await further clinical studies to assess its potential benefit in clinical practice.”

D. John Doyle, MD, PhD, who is a member of the Anesthesiology News advisory board, found the results of the trial encouraging. “As an individual who is no stranger to the endoscopy suite, I occasionally long for a more convenient way to manage the airway for upper GI endoscopy procedures,” said the chief of general anesthesiology at Cleveland Clinic Abu Dhabi, in United Arab Emirates.

“Tracheal intubation is almost always overkill, while the usual option of spontaneous ventilation with a completely unsecured airway becomes problematic when the airway obstructs, a common problem in my patient population, which is unusually rich in obese diabetic individuals.

“The LMA Gastro appears to be the right airway device to fill this void,” Dr. Doyle added. “I look forward to incorporating the device into my clinical practice.”

He will get the chance to do just that, as the device was approved and introduced to the market in early January by Teleflex.

—Michael Vlessides

Dr. Skinner reported that he is the inventor of the LMA Gastro Airway, and has a consultancy agreement with Teleflex, with whom he has conducted initial research and development. The trial reported here, however, was not funded by Teleflex but by a grant from the Royal Hobart Hospital Research Foundation.


Source: Anesthesiology News



Modified Laryngeal Mask Designed to Circumvent Adverse Events from Upper GI Procedures

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