Relationship between dyspnoea and respiratory drive in mechanically ventilated patients: A prospective observational study.

BACKGROUND

Patients with high respiratory drive during mechanical ventilation (MV) may be at risk for ventilator-induced lung injury, making control crucial. While high respiratory drive is often associated with dyspnoea, the relationship remains unclear.

OBJECTIVES

We examined the relationship between three dyspnoea-rating scales and respiratory drive, as measured by airway occlusion pressure (P0.1), in patients receiving MV.

METHODS

A prospective observational study was conducted in the intensive care unit between February 2020 and March 2022. Adults (aged ≥20 years) expected to require MV for over 24 h were included. Dyspnoea was assessed using the Respiratory Distress Observation Scale, Intensive Care-Respiratory Distress Observation Scale, and Mechanical Ventilation-Respiratory Distress Observation Scale. Respiratory drive was measured using P0.1. Measurements were taken at up to two time points between intensive care unit admission and day 4 by two independent investigators blinded to each other's data. Pearson's correlation coefficients were used to assess relationships between dyspnoea scales and P0.1.

RESULTS

Of the 253 eligible patients, 131 were included, and 69 underwent P0.1 measurement. A total of 105 observation points were analysed. Weak negative correlations were found between the Respiratory Distress Observation Scale, Intensive Care-Respiratory Distress Observation Scale, and Mechanical Ventilation-Respiratory Distress Observation Scale and P0.1 (r = -0.293, p = 0.003; r = -0.240, p = 0.014; and r = -0.260, p = 0.008, respectively). Stratified analysis by baseline disease, severity, and sedation showed weak negative correlations only in the deep sedation group (r = -0.347, p = 0.020; r = -0.325, p = 0.029; and r = -0.352, p = 0.018, respectively), stronger than in the overall cohort. No significant correlations were found among groups stratified by disease or severity.

CONCLUSIONS

In patients with MV, weak negative correlations were observed between dyspnoea assessed with the three scales and respiratory drive measured by P0.1.