Diaphragm function in post-upper abdominal surgery: High-flow nasal cannula (HFNC) versus nasal cannula - a pilot study

This pilot study was performed to identify the differences between the effectiveness of HFNC and conventional oxygen therapy. This study was a part of a more extensive ongoing study in a tertiary care hospital from January to April 2019. Criteria for inclusion were adult patients scheduled for upper-abdominal surgery. Patients were randomised into two groups: conventional oxygen therapy (n=10) and HFNC therapy (n=10). The differences in (clinical parameters;Mean Arterial Pressure (MAP), heart rate, respiratory rate), diaphragm thickening on ultrasound, air lung distribution on Electrical Impedance Tomography (EIT), and blood gas analysis data between both groups were assessed at specific times. Adverse events were recorded and treated during the study. The data collected was analysed using SPSS software version 23.0. During the recuritment of patients, no issues were indentified in this study. Therefore, no clinical or statistical differences in EIT and ultrasound diaphragm thickening between the two groups were observed; no clinical or statistical differences in patterns in clinical parameters were found. The mean arterial PO2 was particulary different at time 1: 137.10 mmHg for patients in the conventional therapy group and 93.95 mmHg in the HFNC group (p = 0.001). A patient in the HFNC group reported a feeling of discomfort. The aim of this study was to observe differences between HFNC and conventional oxygen therapy. Nonetheless, more data are needed in order to achieve a conclusive result.