Utility of ultrasound of upper airway for confirmation of endotracheal intubation and confirmation of the endotracheal tube position in the intensive care unit patients

Abstract

Background: Endotracheal intubation in the intensive care unit (ICU) is an extremely high risk procedure. Rapid confirmation of endotracheal tube (ETT) placement and position to the correct depth is vitally important. Various methods are used to confirm placement of ETT. Capnography is the gold standard for confirmation of ETT placement in the trachea, but is not useful for ETT placement at the correct depth in the trachea. We conducted this study to evaluate the utility of airway ultrasonography for real time confirmation of ETT placement and also to confirm appropriate depth of the ETT. Methods: In this prospective, single-centre study, we included all adult patients intubated in the ICU. We obtained deferred consent from the Institutional Ethics Committee. We performed airway ultrasonography real time during intubation and detected ETT placement by loss of snow storm sign. Tracheal placement was also confirmed by capnography. We used saline filled cuff method to place ETT cuff depth at 3 rd and 4 rd tracheal ring and confirmed the appropriateness of the ETT depth on chest X-ray. We calculated the sensitivity and specificity of this technique. Results: We included 89 patients for the study. The ultrasound detection of the placement of the tube with the loss of snow storm sign was seen in 86 patients. The incidence of esophageal intubations was 2.0%. The overall sensitivity of airway ultrasound for confirmation of ETT placement was 96% (CI: 0.89–0.99) and specificity was 100%. The PPV was 100% (CI: 0.94–1.00). The accuracy for appropriateness of final position of ETT by airway ultrasound as compared to X-ray was found to be 96% (CI: 0.71–0.87). No complications were observed related to cuff inflation and deflation and to the use of airway ultrasound. Conclusions: Airway ultrasonography can be used for rapidly detecting ETT placement in the trachea as well as for determining appropriate depth insertion of the ETT with saline filled cuff technique.