Lactate as prognostic factor for length of stay in patients treated with non-invasive mechanical ventilation

Aims and objective: To determine the prognostic value of lactate at admission in patients surviving their first acute hypercapnic respiratory failure (AHRF) episode treated with non-invasive mechanical ventilation (NIV). Methods: Observational study from January of 2010 to December of 2014, including patients treated with NIV whom survived their first AHRF episode. Sociodemographics and medical history were recorded, as well as the main cause of failure. To determine the association of lactate with length of stay, a multivariate linear regression model was carried out after univariate analysis determined other associations along with variables considered relevant by the investigators. Results: A total of 155 patients were included, 78 men (50,1%), mean age of 71,2 ± 11,1 years. Mean length of stay was 7.9 ± 5.6 days, and mean lactate at admission was of 1.68 ± 1.17 mg/dl. In the univariate analysis, higher N-terminal pro-brain natriuretic peptide, pCO2 and lactate values at admission were associated to length of stay, whereas in the multivariate analysis lactate (B coefficient 2.48; CI95% 1.51 – 3.46; p<0.01) and pCO2 (B coefficient 0.09; CI95% 0.03 – 0.16; p=0.04) remained related to longer hospitalizations. Conclusions: Higher concentrations of lactate at admission were associated to longer hospitalizations in patients surviving their first AHRF when treated with NIV