Predictors of high flow nasal cannula failure in immunocompromised patients with acute respiratory failure due to non-HIV pneumocystis pneumonia.

BACKGROUND: To evaluate the predictors of high flow nasal cannula (HFNC) failure in pneumocystis pneumonia (PCP) patients with acute respiratory failure (ARF).

METHODS: Fifty-two non-HIV-related PCP subjects were divided into a HFNC success group (44%) and a HFNC failure group (who required mechanical ventilation (MV) despite HFNC application) (56%). The clinical characteristics and physiologic effects were retrospectively reviewed and compared between the groups.

RESULTS: At baseline, the heart rate, alveolar-arterial PO2 difference [P(A-a)O2 ], Sequential Organ Failure Assessment (SOFA) score, and proportion of subjects who used vasopressors were significantly higher in the HFNC failure group than in the HFNC success group. The 60-day mortality was 52% in the HFNC failure group and 13% in the HFNC success group (P=0.004). The results of the multivariate analysis indicated that the baseline SOFA score was independently associated with HFNC failure (adjusted odds ratio, 1.74 per each score unit increase; 95% CI, 1.05-2.89; P=0.03). Repeated measures analysis of variance revealed that within 6 h of HFNC initiation, the mean PaO2 /FiO2 ratio decreased and the mean P(A-a)O2 increased rapidly in the HFNC failure group.

CONCLUSIONS: Patients with ARF due to PCP subjected to HFNC therapy should be carefully monitored, and particular attention should be paid to those who had organ dysfunction and did not show early oxygenation improvement.