Bilateral auscultation, the current gold standard to detect misplacement of an endotracheal tube during intubation, frequently provides inconclusive results. Serious complications, such as hypoxemia, right-sided barotrauma and left-sided atelectasis, can occur from inadvertent placement of the tube in a mainstream bronchus.

New findings suggest that a three-step test of assessing the placement of an endotracheal tube (ETT) is essentially foolproof, but that as a stand-alone test, the depth of the tube in the airway is a better measure than auscultation.

“If [clinicians] hear breath sounds on either side of the chest, they assume the tube is in the right position,” said David Alfery, MD, associate adjunct professor of anesthesiology at Vanderbilt University, in Nashville, Tenn., who was not part of the study. “But even an experienced anesthesiologist can be fooled.”

The new study “suggests that simply using tube insertion depth, which requires no judgment, better predicts appropriate tube position than the best clinical judgment even by experienced anesthesiologists,” said Daniel I. Sessler, MD, professor and chair of the Department of Outcomes Research at Cleveland Clinic, in Ohio, who helped conduct the research... researchers found that the optimal tube insertion depth is 20 cm in women and 22 cm in men. “Perhaps using a general 20/22 cm rule, with the possible exception of using 19 cm for smaller women with a higher body mass index, might be a safer approach,” Dr. Sessler suggested. Based on these results, he said, physicians should rely more on insertion depth than on auscultation.

However, combining all three tests—bilateral auscultation of the lungs, observation and palpation of the symmetrical chest movements, and referencing the ETT centimeter scale—provided the most sensitivity, hitting 100%, Dr. Sessler said. Still, tube depth, with a sensitivity of 88%, was significantly more sensitive for detecting endobronchial intubation than either auscultation (65%) or observation (43%) (P<0.001), the researchers found.