The self-inflating bulb as an airway adjunct: is it reliable in children weighing less than 20 kilograms?

OBJECTIVES: To confirm the ability of the self-inflating bulb to indicate endotracheal tube (ETT) position in children weighing less than 20 kilograms, and to determine whether the presence of air in the stomach affects the bulb's accuracy. METHODS: This single-blind, prospective, single-cohort, repeated-measures, equivalence study was conducted in the operating room of a children's hospital. Seventy patients weighing less than 20 kilograms were enrolled. All patients had an uncuffed ETT placed in both the trachea and the esophagus. Measurements were initially obtained on both tubes without the presence of air in the stomach using the on-deflate method (the bulb is compressed after attachment to the ETT). Five mL/kg of air was then insufflated into the stomach and two additional measurements were obtained on each patient. The order in which the bulb was checked was determined by a computer-generated permuted block randomization scheme. The blinded assessor told the anesthesiologist when to start and stop the clock after each intervention. Five seconds was used as the cutoff time for which the clock was stopped. If the bulb re-expanded within 5 seconds, then the tube was considered to be in the trachea; if it did not re-expand, then this was considered to be an esophageal intubation. RESULTS: Median patient age was 2 years. The on-deflate method without air in the stomach had a sensitivity of 100% and a specificity of 94% for detecting tracheal intubations. With air in the stomach, the bulb had a sensitivity of 97% and a specificity of 96% (95% confidence interval [95% CI] for the difference between methods: sensitivity -3 to 10; specificity -10 to 7). The inaccuracy rate for the on-deflate method without air in the stomach was 3%, whereas the inaccuracy rate with air in the stomach was 4% (Delta -1, 95% CI = -5 to 4). There were no false positives or false negatives in the 24 patients weighing between 5 and 10 kilograms. CONCLUSIONS: The self-inflating bulb is a reliable method of detecting endotracheal tube position in children weighing less than 20 kg, even with the use of uncuffed endotracheal tubes. Furthermore, the presence of air in the stomach, simulating field conditions, does not affect bulb effectiveness in detecting endotracheal tube position.

The self-inflating bulb as an esophageal detector device in children weighing more than twenty kilograms: a comparison of two techniques.

STUDY OBJECTIVES: We confirm the ability of the self-inflating bulb to indicate endotracheal tube position in children and determine which method of bulb compression is more accurate. METHODS: This single-blind, prospective, single cohort, repeated measures comparison of the on-deflate and the off-deflate methods of bulb compression was conducted in the operating room of a children's hospital. Seventy-five patients weighing more than 20 kg were enrolled. All patients had an endotracheal tube placed in both the trachea and the esophagus, 5 mL/kg of air was insufflated into the stomach, and 4 measurements were obtained on each patient. The bulb was either applied to the endotracheal tube and then compressed (on-deflate method), or compressed before its attachment to the endotracheal tube (off-deflate method). The order in which the methods were utilized was determined by a computer-generated permuted block randomization scheme. The blinded assessor told the anesthesiologist when to start and stop the clock after each intervention. Five seconds was used as the cut-off time for which the clock was stopped. If the bulb reexpanded within 5 seconds, then the tube was considered to be in the trachea; if it did not reexpand, then this was considered to be an esophageal intubation. RESULTS: The mean patient age was 11 years. The on-deflate method had a sensitivity of 99% and a specificity of 92% for detecting tracheal intubations. The off-deflate method had a sensitivity of 99% and a specificity of 100% (95% confidence interval [CI] for the difference between methods: sensitivity -6 to 6, specificity -14 to 0.4). The inaccuracy rate for the off-deflate method was 1%, whereas the inaccuracy rate for the on-deflate method was 5% (Delta4; 95% CI 0.2 to 9). CONCLUSION: The self-inflating bulb is a reliable method of detecting endotracheal tube position in children. Furthermore, the off-deflate method may be more reliable and accurate than the on-deflate method when used in children weighing more than 20 kg.