A propensity score-adjusted analysis of efficacy of high-flow nasal oxygen during awake tracheal intubation

0
196


Study design and ethical approval

This single-center, retrospective cohort study was approved by the Institutional Review Board of Severance Hospital, Seoul, South Korea (Approval Number: 4-2021-0901; August 21, 2021). The requirement for written informed consent was waived due to the retrospective nature of the study. This study followed the guidelines of the Declaration of Helsinki (1964) and its later amendments (2013).

Patients

We included patients who underwent ATI for surgery at Severance Hospital, Yonsei University Health System, Seoul, Korea, between March 2017 and May 2021. We excluded the following patients: those who underwent other procedures, for example, arterial line cannulation, before ATI and after entering the operation room, and those with incomplete data on oxygen saturation, attempt numbers, and time taken for ATI. However, we did not exclude cases where the time taken for ATI could not be specified due to failed ATI.

The patients were divided into HFNO and conventional oxygenation groups. The conventional oxygenation group received low-flow oxygen through a standard nasal cannula or a simple face mask.

Data collection

We retrospectively reviewed the electronic medical records of the included patients and retrieved the following baseline characteristics: age, sex, height, weight, body mass index, nature of the operation (emergency or elective), American Society of Anesthesiologists physical status classification, history of hypertension, coronary arterial occlusive disease, congestive heart failure, chronic obstructive pulmonary disease, and previous radiotherapy and/or surgery for head and neck cancer.

We also recorded pre-procedural data, including airway bleeding, need for oxygen supplementation before entering the operating room, and initial oxygen saturation at the time of entering the operating room.

Moreover, we recorded intra-procedural data on oxygen saturation, intravenously administered drugs for ATI (glycopyrrolate, remifentanil, dexmedetomidine, or propofol), intra-procedural position of the patient (supine or sitting), HFNO utilization, performance of trans-tracheal block, intubation performer, intubation route (nasal or oral), multiple attempts (more than two attempts), duration of ATI (interval between entry to the operating room and ATI completion), successful or failed ATI, and occurrence of adverse effects (barotrauma or direct contact airway injury) during ATI.

Study endpoints

The primary endpoint was the lowest oxygen saturation during ATI. The secondary endpoints were incidences of desaturation (oxygen saturation < 90%), multiple attempts, failure, and the procedural duration.

Statistical analysis

Continuous variables were analyzed using an independent t-test. Categorical variables were analyzed using the chi-square test or Fisher’s exact test. Numerical data were presented as mean (standard deviation). Categorical variables were presented as counts and percentages. Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 26.0 (IBM Corp., Armonk, NY, USA), R version 3.6.0 (The R Foundation for Statistical Computing, Vienna, Austria), and SAS version 9.4 (SAS Inc., Cary, NC, USA). Statistical significance was set at P < 0.05.

The IPTW method was used to balance the groups for the baseline characteristics of the patients and the procedural environments. We estimated the propensity scores using a multiple logistic regression model based on the following variables: age, sex, body mass index, nature of the operation (emergency or elective), presence of chronic obstructive pulmonary disease, pre-procedural airway bleeding, need for oxygen supplementation before entering the operating room, drugs used for ATI (glycopyrrolate, remifentanil, dexmedetomidine, or propofol), intra-procedural patient position (supine or sitting), performance of trans-tracheal block, intubation performer, and intubation route (nasal or oral). The between-group balance was assessed using the absolute standardized differences (ASDs). Variables with an ASD < 0.2 were considered to have an acceptable balance12. We used stabilized weights to reduce variability in the IPTW analysis.

After the IPTW adjustment, continuous variables were analyzed using an adjusted independent t-test by weighting the individual contributions, while categorical variables were analyzed using the Pearson chi-squared test after the Rao–Scott second-order correction. Continuous outcome variables were further analyzed using a multivariable linear regression model by weighting the individual contributions to correct for the confounding effect of variables with ASD > 0.1. The regression model approach was not applied for the categorical outcome variables due to the small number of events.



Source link