Non-Invasive Mechanical Ventilation: How to Identify Response?

Abstract

Introduction: Noninvasive mechanical ventilation has been
established as a successful therapeutic option in respiratory
failure, as it reduces the complications associated with invasive mechanical ventilation and improves hospital survival.
Our objectives was to describe a population of patients who
needed noninvasive mechanical ventilation at an Intermediate Care Unit and identify possible predictive indicators of
response to therapy.
Methods: Prospective observational study conducted over 6
months that included patients with hypercapnic and/or hypoxemic respiratory failure which needed noninvasive mechanical ventilation.
Results: Thirty-four of 128 patients were identified, mean age
77 year-old, 71% male. Score SAPS II and average Charlson
index of 46 and 7, respectively. Twenty-two patients started
noninvasive mechanical ventilation at the Emergency Department, 6 at the unit and the remaining 6 at the Internal
Medicine ward. Main reasons for its introduction: acute cardiogenic lung edema (50%) and acute chronic obstructive
pulmonary disease (26%). The rate of therapeutic failure was
29%. After 24 hours of noninvasive mechanical ventilation,
the differences found between the response and the therapeutic failure group were statistically significant (pH 7.37
vs 7.32; p <0.05). Ph variation in the first few hours seems
to be associated with a better ability to predict noninvasive
mechanical ventilation response (0.894, p = 0.001).
Conclusion: Noninvasive mechanical ventilation reduces patient morbi/mortality through close clinical and arterial gasimetry monitoring. pH variation seems to be the best predictor of
response, allowing early recognition of therapeutic failure and
facilitating the use of other therapeutic options in advance.