Flow‐pressure characteristics of an Intersurgical adjustable pressure‐limiting valve

Abstract

The adjusted difference in mean time for tracheal intubation was 60.9 (95% CI 20.5-101.3; p = 0.003) seconds faster in the videolaryngoscope group. We found no other statistically significant differences.Although this study lacks the statistical power to compare secondary outcomes between groups, we are confident that videolaryngocopy enables significantly faster tracheal intubation in bariatric patients with predicted difficult airways compared to fibreoptic bronchoscopy. It is unlikely that this resulted from differences in sedation or topical anesthesia, as the bispectral indices and airway reaction scores were comparable between the groups. We would welcome confirmation of our findings by other researchers.

Going around in circles. Is there a continuing need to use the T‐piece circuit in the practice of pediatric anesthesia?

“…It should be noted that most APL valves are not calibrated for pressure and the blow off pressure may alter between circuits and at different flow rates. 15,16 Use of pressure monitoring, with or without an APL valve, will allow control of airway pressure and should be considered either as a routine or selectively when caring for more vulnerable patients.…”

“…When we discussed scavenging the addition of an APL valve was discussed and when describing the use in neonatal resuscitation the use of pressure monitoring was mentioned. It should be noted that most APL valves are not calibrated for pressure and the blow off pressure may alter between circuits and at different flow rates 15,16 . Use of pressure monitoring, with or without an APL valve, will allow control of airway pressure and should be considered either as a routine or selectively when caring for more vulnerable patients.…”

Flow‐pressure characteristics of four adjustable pressure‐limiting valves supplied with Mapleson C circuits

“…Having read our previous work [2], Armstrong Medical's representative approached us to ask if we would consider analogous testing of the APL valve from their system. Armstrong Medical provided a sample for the purpose free of charge, which we received inside sealed original packaging.…”

“…In general, the adult APL valves behave more linearly with increasing flow rates. Therefore, as we previously observed [2], increasing flow beyond the maximum displayed value of 15 l.min −1 from a typical ward‐based oxygen rotameter is likely to give more linear valve performance in addition to reducing re‐breathing.…”

“…There is no consensus on the ideal characteristics of an adjustable pressure‐limiting (APL) valve [1], but they are covered by the regulatory standard ISO 80601‐2‐13:2011. In 2017, we investigated the flow‐pressure characteristics of an APL valve from an Intersurgical Mapleson C circuit [2]. Subsequently, a manufacturer approached us to ask if we would consider testing the APL valve from their system.…”