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Indian J Crit Care Med
Indian J Crit Care Med
IJCCM
Indian Journal of Critical Care Medicine : Peer-reviewed, Official Publication of Indian Society of Critical Care Medicine
0972-5229
1998-359X
Jaypee Brothers Medical Publishers

39130382
10.5005/jp-journals-10071-24740
Letter to the Editor
Author Response: Beyond the Nasal Prongs: A Joust of Oxygen Delivery Methods in Post-op Hypoxemia
Mishra Susri 1https://orcid.org/0009-0002-4550-5849

Kothari Nikhil 2https://orcid.org/0000-0002-9829-905X

Sharma Ankur 3https://orcid.org/0000-0001-9339-6988

Goyal Shilpa 4https://orcid.org/0000-0002-8983-0953

Rathod Darshana K 5https://orcid.org/0000-0002-4007-0682

Meshram Tanvi 6https://orcid.org/0000-0002-4625-6357

Bhatia Pradeep K 7https://orcid.org/0000-0001-5082-7151

1,2,4–7 Department of Anesthesia and Critical Care, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
3 Department of Trauma & Emergency (Anaesthesia & Critical Care), All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
Ankur Sharma, Department of Trauma & Emergency (Anaesthesia & Critical Care), All India Institute of Medical Sciences, Jodhpur, Rajasthan, India, Phone: +91 9654045653, e-mail: ankuranaesthesia@gmail.com
6 2024
31 5 2024
28 6 626627
Copyright © 2024; The Author(s).
2024
https://creativecommons.org/licenses/by-nc/4.0/ © The Author(s). 2024 Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and non-commercial reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
How to cite this article: Mishra S, Kothari N, Sharma A, Goyal S, Rathod DK, Meshram T, et al. Author Response: Beyond the Nasal Prongs: A Joust of Oxygen Delivery Methods in Post-op Hypoxemia. Indian J Crit Care Med 2024;28(6):626–627.

Keywords

Hypoxemia
Oxygenation
P/F ratio
==== Body
pmcDear Editor,

We thank Dr Gangireddy and Dr Jindal for their interest in our study and insightful comments.

We included postoperative adult patients aged between 18 and 65 years with hypoxemia who were kept for monitoring in a postanesthesia care unit (PACU) after undergoing surgeries.1 All cases recruited were only after elective surgeries without anemia. As of now, partial pressure of oxygen (PaO2) is the only standard way to measure hypoxia. No other method is available to measure pO2 directly at the tissue level.

In our study, selection was normally distributed and not skewed. It was an open-label random study to remove selection bias. The primary outcome variable was a change in the PaO2 to the fraction of inspiratory oxygen concentration (FiO2) (P/F) ratio represented as mean and standard deviation. The comfort score may be subject to individual variation. Thus, the data for the comfort score was represented as a median.

Block or stratified randomization would have been possible if all the subjects had been identified before the group assignment, which was not the case in our study.2 Patients with covariates that could influence the outcome of our trial were excluded. So, we took simple randomization for its ease of implementation.

All three 3 oxygen delivery vehicles (ODVs), i.e., non-invasive ventilation (NIV), high-flow nasal cannula (HFNC), and venturi mask (VM), are used for oxygen delivery in the PACU depending upon the clinician preferences. No similar study has been done to date in the Indian scenario on postoperative adult patients. The conditions mentioned by Gangireddy et al. occur in critical care patients admitted to the intensive care unit, not after elective surgeries.

We agree that the short-term effects of oxygen-delivery devices may not truly reflect their long-term effectiveness. In our study, patients not showing improved arterial blood gas (ABG) analysis parameters were either shifted to ICU or the ODV was changed according to the patient's pathophysiology. We opted for a random selection of ODV rather than patient-tailored management, as suggested by Gangireddy et al., which would have been more beneficial. Our main goal was not to treat the pathophysiology but to improve oxygenation when the patient stays at PACU.

We followed up with the patients for two hours instead of longer durations. However, the patients who required a longer duration of ODV or deteriorated were shifted to the ICU for further management. Those who showed improvement and no longer required the support of ODV were shifted to wards with an oxygen face mask or on room air, making it pointless to follow up. Since the average holding time in PACU at our institute is approximately 2 hours, this was the rationale behind the primary outcome, i.e. a change in the PaO2/FiO2 ratio after 2 hours of oxygen use.3 In postoperative patients, hypoxemia occurs due to basal atelectasis and inadequate recovery from anesthesia. After surgery under general anesthesia, patients have kept nil orally for 2 hours to prevent aspiration till they completely recover from anesthesia. As per enhanced recovery after surgery (ERAS) protocol, patients should mobilize as early as possible.4

In our study, the settings of the ODV were fixed and not patient-tailored, which has already been mentioned as a limitation. Because patients were kept nil by mouth during the postoperative period, the ease of taking oral fluids or an oral diet utilizing various ODVs could not be tested, which is also a limitation of our study.

Orcid

Susri Mishra https://orcid.org/0009-0002-4550-5849

Nikhil Kothari https://orcid.org/0000-0002-9829-905X

Ankur Sharma https://orcid.org/0000-0001-9339-6988

Shilpa Goyal https://orcid.org/0000-0002-8983-0953

Darshana K Rathod https://orcid.org/0000-0002-4007-0682

Tanvi Meshram https://orcid.org/0000-0002-4625-6357

Pradeep K Bhatia https://orcid.org/0000-0001-5082-7151

Source of support: Nil

Conflict of interest: None
==== Refs
References

1. Mishra S Kothari N Sharma A Goyal S Rathod D Meshram T et al. Comparison of oxygen delivery devices in postoperative patients with hypoxemia: An open-labelled randomized controlled study Indian J Crit Care Med 2024 28 3 294 298 10.5005/jp-journals-10071-24659 38477006
2. Selukar S May S Law D Othus M Stratified randomization for platform trials with differing experimental arm eligibility Clin Trials 2021 18 5 562 569 10.1177/17407745211028872 34420417
3. Fang L Wang Q Xu Y Postoperative discharge scoring criteria after outpatient anesthesia: A review of the literature J Perianesth Nurs 2023 38 4 642 649.e1 10.1016/j.jopan.2022.11.008 36670045
4. Altman AD Helpman L McGee J Samouëlian V Auclair MH Brar H et al Society of Gynecologic Oncology of Canada's Communities of Practice in ERAS and Venous Thromboembolism Enhanced recovery after surgery: Implementing a new standard of surgical care CMAJ 2019 191 17 E469 E475 10.1503/cmaj.180635 31036609
