We thank you for your interest in reading the article by Ramsingh et al.1 and our accompanying editorial2 and appreciate the concerns raised in the letters that auscultation may not have been optimally performed, that the cost of using ultrasound to differentiate tracheal versus bronchial intubation might not have been properly appreciated (Dr. Levy), or that the editorial dismisses the stethoscope as a useless thing of the past (Dr. Jablons).
In their article, Ramsingh et al.1 stated: “Since auscultation for breath sounds is regarded as a basic skill, all attending anesthesiologists, with more than 4-yr posttraining, were allowed to perform the auscultation examination.” We assumed that auscultation would be optimally performed, but we also contacted Dr. Ramsingh and obtained more detailed information about their auscultation technique. Dr. Ramsingh responded: “Manual ventilation was initiated with target volumes of approximately 8 to 10 ml/kg ideal body weight, auscultation was performed bilaterally in each axilla at the mid-axillary line (approximately at the level of the fifth rib space).” This description of the auscultation technique represents a reasonable practice and may exceed the quality of true clinical practice. In this regard, we think that the comparison is reasonable: a new technique versus a routine clinical practice. In addition, there are several other studies demonstrating low sensitivity and specificity of auscultation for differentiating tracheal versus bronchial intubation, and the values Ramsingh et al.1 reported in their study are comparable with those reported by other investigators.3–5 Nevertheless, we do agree with you that the sensitivity and/or specificity of auscultation might improve if it was executed in combination with other clinical assessments as you suggested. However, the sensitivity and specificity of auscultation unlikely approach the sensitivity (93%) and specificity (96%) obtained with ultrasound alone.1
Regarding the cost of using ultrasonography to assess the appropriate endotracheal tube cuff location, portable ultrasound devices are already widely available in the perioperative setting. For the purposes of financial analysis, it is reasonable to posit that new devices are not purchased specifically for only assessing the endotracheal tube cuff position, so the incremental cost of additional uses of existing equipment is the appropriate analysis. Because the probe is used for skin (not mucosa) contact only, the level of cleaning and sterilization requirement is much less rigid than that of cleaning and sterilization for a device such as a fiberoptic bronchoscope. We could not find any quote of the cost to wipe down the probe, screen, and keyboard of the ultrasound device with a sanitizing wipe. However, the cost estimate for one wipe and 3 to 5 min of a technician’s time is surely minimal.
The key message of our editorial is to emphasize that unquestioning reliance on the auscultation technique is not supported by scientific observation and to point out the value of exploring better techniques for common tasks (such as the ultrasound technique for endotracheal tube positioning). Innovation should always remain in our interests as we strive to improve the safety and reliability of anesthesiology. We are not recommending abandoning the stethoscope and do agree with its usefulness for a variety of clinical situations when properly used (including proper cleaning between patients to avoid transmission of disease). However, we must appreciate the low sensitivity and specificity of auscultation, even in the hands of experienced clinicians. We agree that the well-trained clinician needs to use all of his or her senses, including common sense, to provide optimal care for their patients.
The authors declare no competing interests.