Prevalence and clinical significance of acute respiratory failure in patients with acute heart failure admitted to intensive care
S Sharipov, Z A Sharipov, M V Petrova, M D ZH Yodgorova, I Merai, Z H D KobalavaAbstract
Background
Acute respiratory failure (ARF) is a frequent complication of acute heart failure (AHF) and is associated with adverse in-hospital outcomes. Despite its high clinical relevance, data on the prevalence, severity, phenotypic associations, and prognostic impact of ARF in intensive care populations remain limited.
Aim
To assess the prevalence, severity, risk factors, and clinical significance of ARF in patients with AHF admitted to intensive care.
Methods
This single-center observational study included 218 consecutive patients admitted with AHF to the cardiac intensive care unit of a university hospital. ARF was defined as arterial oxygen saturation (SpO₂) <95% with clinical signs of respiratory distress and classified into three severity grades. Clinical phenotypes, need for respiratory and hemodynamic support, length of hospital stay, and in-hospital mortality were analyzed. Multivariate logistic regression was used to identify independent predictors of ARF requiring respiratory support. Statistical significance was set at p<0.05.
Results
Hypoxemia (SpO₂ <95%) was observed in 199 patients (91.3%). ARF grade I occurred in 161 patients (73.9%), grade II in 33 (15.1%), and grade III in 5 (2.3%). Respiratory support was required in 194 patients (89.0%): low-flow oxygen therapy in 144 (66.1%), high-flow oxygen therapy in 24 (11.0%), non-invasive ventilation in 26 (11.9%), and invasive mechanical ventilation in 21 (9.6%). Severe ARF (grades II–III) was significantly more frequent in patients with isolated right ventricular failure compared to other AHF phenotypes (p=0.01). Independent predictors of ARF requiring respiratory support were chronic kidney disease (OR 9.5; p=0.03) and chronic lung disease (OR 7.6; p=0.05). ARF grade III was associated with prolonged hospitalization and increased in-hospital mortality (both p=0.04).
Conclusions
ARF is highly prevalent among patients with AHF admitted to intensive care and is predominantly mild, most often requiring low-flow oxygen therapy. However, severe ARF is associated with worse in-hospital outcomes, particularly in patients with isolated right ventricular failure. Early assessment of oxygenation and respiratory status may facilitate timely initiation of respiratory support and improve risk stratification in this high-risk population.