Listening to breathing again

Failure to rescue is a measure of quality of care of a health care system. Mortality and complication rates for patients are influenced by the severity of illness of the patients. Therefore ‘‘risk-adjusted’’ rates are produced. A hospital tries to justify that it’s higher complication rate is because their patients are sicker. Failure to rescue a patient who gets into trouble is dependent on the hospital characteristics more than the severity of illness of the patients. This is more a measure of the quality of care that the hospital is providing [1]. To be able to respond to a patient getting into distress in a timely manner, so that the chances of rescue are high are dependent on many factors and one of these is good patient monitoring. The ideal monitor has not been available to prevent respiratory depression from oversedation. Pulse oximetry when used needs to be continuous and observed continually or have a closed loop notification system for alarms. The observer must understand the effect that the administration of supplemental oxygen has on the ability of the pulse oximeter to detect respiratory depression. When oxygen is being administered through a nasal cannula, apnea may exist for many minutes before oxygen desaturation occurs. When the pulse oximeter alarms goes off the partial pressure of arterial carbon dioxide may be over 100 mmHg, making an immediate intervention necessary to avert an adverse outcome [2]. A significant number of patients have been harmed by the unrecognized respiratory depressive effects of postoperative opioids and this has caused the Anesthesia Patient Safety Foundation and the Joint Commission to issue warnings about the need to continually monitor oxygenation together with a monitor of ventilation in patients receiving oxygen [3, 4]. Capnography has been considered the ‘‘gold standard’’ for monitoring ventilation but has many drawbacks. Many patients, especially children, do not tolerate the presence of nasal cannulas for long and will dislodge them [5].The accurate clinical value of end-tidal carbon dioxide (EtCO2) relies on the adequate mixing of expired gas with alveolar gas. If the patient is hypoventilating this mixing may not occur and a low value for EtCO2 may be recorded. Tanaka et al. [6] have examined the problem of detecting apnea during sedation procedures. They have compared the sensitivity of capnography and acoustic monitors in detecting apnea during sedation and also examined the depth of the sedation, as measured by a cerebral function monitor and the calculated Patient State Index, to see if this index—depth of sedation—correlated with the incidence of respiratory pauses. This prospective study confirms the work previously reported that acoustic monitoring is as accurate as capnography for monitoring respiratory rate [7, 8]. However this study also strengthens the data previously reported that the acoustic monitor may be more sensitive in detecting apnea than capnography. The PSI did not correlate with respiratory pauses and this may be because this is a calculated number that there is a lag time to display. It is possible that if the ‘‘real time’’ raw electroencephalograph signal was observed in all the patients, that depth of anesthesia may indeed have been a factor in the presence or absence of respiratory pauses. The development of new more robust and patient friendly technology like the acoustic monitor potentially may improve the safety of our patients. This Editorial refers to the article available at doi:10.1007/s10877014-9556-8.