Gas Insufflation During Endoscopy May Cause Cardiovascular Events

Gas insufflation during any endoscopic procedure runs the risk for increased abdominal pressure, potentially leading to an unplanned cardiovascular event.

“Anesthesiologists should be concerned with the amount of time an endoscopy procedure may entail,” said Paul Terracciano, MD, a senior attending anesthesiologist and the former director of anesthesiology at Phelps Hospital (Northwell Health), in Sleepy Hollow, N.Y. “The longer the procedure time, the greater the volume and potential pressure of either air or carbon dioxide [CO₂] insufflated within the lumen of the body.”

Dr. Terracciano noted that over the past five years, there has been a 32% increase in closed claims involving the gastrointestinal suite, with the majority of these claims stemming from air insufflation.

These physiologic imbalances may lead to difficulty breathing, resulting in respiratory distress, reflexive bradycardia and diminished cardiac output manifested by a change to or loss of the pulse oximeter waveform. “These imbalances could cause an unplanned cardiac event,” said Dr. Terracciano, who has a background in analytical chemistry and gas chromatography–mass spectrometry instrumentation.

Case Illustration

“However, at the end of the procedure, after the endoscope had been removed, the patient showed increased work of breathing and shallow breath sounds,” Dr. Terracciano said. There also was a sudden loss of the oxygen saturation waveform, which was accompanied by pulseless electrical activity.

Within one respiratory cycle, the patient incurred bradycardia with loss of blood pressure. “Clinically, the changing and then acute loss of the pulse oximeter waveform, coupled with pulseless electrical activity, reflects poor or no venous return to the heart,” Dr. Terracciano said. “This is from increased abdominal pressure by the unmonitored gas insufflation into the patient’s colon.”

Follow-up lab tests, chest x-rays and blood gas revealed pronounced elevation of the right hemidiaphragm, small lung volumes, platelike atelectasis and significant right colonic dilation associated with a large alveolar–arterial gradient (i.e., the A-a gradient). “Because air does not diffuse rapidly, it remains in the body longer than CO₂,” Dr. Terracciano said. “The chest x-ray and the A-a gradient lead us to understand that the air is trapped in the colon. The oxygenation problem also continues after the procedure is over because of the distended colon pushing up on the diaphragm and the lungs.”

To decrease unplanned cardiovascular events, Dr. Terracciano recommended that the endoscopist and anesthesiologist monitor and be aware of the amount (volume) and intraluminal pressure of gas insufflated into the patient. “This is a shared responsibility and necessary communication between the two disciplines,” he said.

High or back pressure alarms are also not installed on the regulators by manufacturers. “To overcome this hurdle, the insufflation of gas can be coupled with smart electronic software to alarm when either volume and/or pressure are above a critical maximum,” Dr. Terracciano said.

Dr. Terracciano noted that over the past two years, there has been greater use of CO₂ insufflation because of the rapid absorption/diffusion of CO₂ by the body compared with air. “However, volumes and pressure of any unmonitored gas in the body can and will, at some critical point, cause physiologic derangement,” he said. “Much improvement can be done in manufacturing as well as in the monitoring, recording and communication between the endoscopist and anesthesiologist.”

At this time, the vast majority of endoscopy procedures need either air or CO₂ insufflation to open and visualize the lumen, according to Dr. Terracciano. “And for a select group of patients, a ‘virtual’ camera endoscopy may be a viable alternative to a standard endoscopy procedure,” he said.

—Bob Kronemyer