Determining the effective pre-oxygenation interval in obstetric patients using high-flow nasal oxygen and standard flow rate facemask: a biased-coin up-down sequential allocation trial
- 1 May 2020
- journal article
- research article
- Published by Wiley in Anaesthesia
- Vol. 75 (5), 609-616
- https://doi.org/10.1111/anae.14995
Abstract
Using biased-coin sequential allocation, we sought to determine the effective time interval in 90% of healthy parturients to achieve a target endpoint end-tidal oxygen of >= 90% using standard flow rate facemask and high-flow nasal oxygen. Eighty healthy parturients were randomly assigned to standard facemask (n = 40) or high-flow nasal oxygen (n = 40) groups; half of the parturients in the high-flow nasal oxygen group also used a simple no-flow facemask to minimise air entrainment. The effective time interval for 90% of parturients to achieve the target endpoint for standard facemask was 3.6 min (95%CI 3.3-6.7 min), but could not be estimated for the high-flow nasal oxygen groups with or without an additional simple facemask, as eight minutes was insufficient to achieve the target endpoint for 55% and 92% of parturients, respectively. Furthermore, after three minutes, the target endpoint was reached by 71% in the standard facemask group vs. 0% in the high-flow nasal oxygen groups. After four minutes, the target endpoint was reached by 100% in the standard facemask, 80% in the high-flow nasal oxygen with simple facemask and 67% in the high-flow nasal oxygen groups. Beyond four minutes, there was no improvement in pre-oxygenation success using high-flow nasal oxygen. In conclusion, under the conditions of our study, the effective time interval for 90% of parturients to achieve an end-tidal oxygen >= 90% for standard flow rate facemask was estimated to be 3.6 min, but could not be estimated for high-flow nasal oxygen groups even after eight minutes.Keywords
This publication has 23 references indexed in Scilit:
- High‐flow humidified nasal oxygenation vs. standard face mask oxygenationAnaesthesia, 2016
- Intrathecal Hydromorphone and Morphine for Postcesarean Delivery Analgesia: Determination of the ED90 Using a Sequential Allocation Biased-Coin MethodAnesthesia & Analgesia, 2016
- The ED90 of Prophylactic Oxytocin Infusion After Delivery of the Placenta During Cesarean Delivery in Laboring Compared with Nonlaboring WomenAnesthesia & Analgesia, 2015
- Transnasal Humidified Rapid‐Insufflation Ventilatory Exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airwaysAnaesthesia, 2014
- Advances in and Limitations of Up-and-down MethodologyAnesthesiology, 2007
- Standard preoxygenation technique versus two rapid techniques in pregnant patientsInternational Journal of Obstetric Anesthesia, 2004
- Dose Finding Using the Biased Coin Up‐and‐Down Design and Isotonic RegressionBiometrics, 2002
- A Random Walk Rule for Phase I Clinical TrialsBiometrics, 1997
- Preoxygenation in healthy volunteers: a graph of oxygen “washin” using end-tidal oxygraphyBritish Journal of Anaesthesia, 1994
- LUNG FUNCTION STUDIES. I. THE RATE OF INCREASE OF ARTERIAL OXYGEN SATURATION DURING THE INHALATION OF 100 PER CENT O21JCI Insight, 1948