ABSTRACT
BACKGROUND: Patients with severe cardiogenic pulmonary edema (CPE) are frequently hypercapnic, possibly because of associated underlying chronic lung disease (CLD). Since hypercapnia has been associated with outcome, we aimed to identify factors associated to hypercapnia and its role on outcome of patients with CPE and no underlying CLD. METHODS: Observational cohort study using data prospectively collected over a 3-year period. After excluding patients with any CLD or obstructive sleep apneas, all patients treated by non-invasive ventilation (NIV) for severe CPE were included. Hypercapnia was defined as PaCO2 >45 mmHg and non-rapid favorable outcome was defined as the need for intubation or continuation of NIV for more than 48 h. RESULTS: After excluding 60 patients with underlying CLD or sleep apneas, 112 patients were studied. The rates of intubation and of prolonged NIV were 6.3 % (n = 7) and 21.4 % (n = 24), respectively. Half of the patients (n = 56) had hypercapnia upon admission. Hypercapnic patients were older, more frequently obese, and were more likely to have a respiratory tract infection than non-hypercapnic patients. Hypercapnia had no influence on intubation rate or the need for prolonged NIV. However, patients with severe hypercapnia (PaCO2 >60 mmHg) needed longer durations of NIV and intensive care unit (ICU) stay than the others. CONCLUSIONS: Among the patients admitted for severe CPE without CLD, half of them had hypercapnia at admission. Hypercapnic patients were older and more frequently obese but their outcome was similar compared to non-hypercapnic patients. Patients with severe hypercapnia needed longer durations of NIV than the others without increase in intubation rate.
ABSTRACT
INTRODUCTION: We assessed rates and predictive factors of non-invasive ventilation (NIV) failure in patients admitted to the intensive care unit (ICU) for non-hypercapnic acute hypoxemic respiratory failure (AHRF). METHODS: This is an observational cohort study using data prospectively collected over a three-year period in a medical ICU of a university hospital. RESULTS: Among 113 patients receiving NIV for AHRF, 82 had acute respiratory distress syndrome (ARDS) and 31 had non-ARDS. Intubation rates significantly differed between ARDS and non-ARDS patients (61% versus 35%, P = 0.015) and according to clinical severity of ARDS: 31% in mild, 62% in moderate, and 84% in severe ARDS (P = 0.0016). In-ICU mortality rates were 13% in non-ARDS, and, respectively, 19%, 32% and 32% in mild, moderate and severe ARDS (P = 0.22). Among patients with moderate ARDS, NIV failure was lower among those having a PaO2/FiO2 >150 mmHg (45% vs. 74%, p = 0.04). NIV failure was associated with active cancer, shock, moderate/severe ARDS, lower Glasgow coma score and lower positive end-expiratory pressure level at NIV initiation. Among intubated patients, ICU mortality rate was 46% overall and did not differ according to the time to intubation. CONCLUSIONS: With intubation rates below 35% in non-ARDS and mild ARDS, NIV stands as the first-line approach; NIV may be attempted in ARDS patients with a PaO2/FiO2 > 150. By contrast, 84% of severe ARDS required intubation and NIV did not appear beneficial in this subset of patients. However, the time to intubation had no influence on mortality.
Subject(s)
Intubation, Intratracheal/adverse effects , Noninvasive Ventilation/statistics & numerical data , Respiratory Distress Syndrome/therapy , Respiratory Insufficiency/therapy , Female , Glasgow Coma Scale , Hospital Mortality , Humans , Intensive Care Units/statistics & numerical data , Intubation, Intratracheal/methods , Intubation, Intratracheal/statistics & numerical data , Male , Middle Aged , Noninvasive Ventilation/adverse effects , Noninvasive Ventilation/methods , Outcome and Process Assessment, Health Care , Prospective Studies , Respiratory Distress Syndrome/mortality , Respiratory Insufficiency/mortality , Risk Assessment , Survival AnalysisABSTRACT
BACKGROUND: Failure of noninvasive ventilation (NIV) is common in patients with COPD admitted to the ICU for acute hypercapnic respiratory failure (AHRF). We aimed to assess the rate of NIV failure and to identify early predictors of intubation under NIV in patients admitted for AHRF of all origins in an experienced unit. METHODS: This was an observational cohort study using data prospectively collected over a 3-year period after the implementation of a nurse-driven NIV protocol in a 24-bed medical ICU of a French university hospital. RESULTS: Among 242 subjects receiving NIV for AHRF (P(aCO2) > 45 mm Hg), 67 had cardiogenic pulmonary edema (CPE), 146 had acute-on-chronic respiratory failure (AOCRF) (including 99 subjects with COPD and 47 with other chronic respiratory diseases), and 29 had non-AOCRF (mostly pneumonia). Overall, the rates of intubation and ICU mortality were respectively 15% and 5%. The intubation rates were 4% in CPE, 15% in AOCRF, and 38% in non-AOCRF (P < .001). After adjustment, non-AOCRF was independently associated with NIV failure, as well as acidosis (pH < 7.30) and severe hypoxemia (P(aO2)/F(IO2) ≤ 200 mm Hg) after 1 hour of NIV initiation, whereas altered consciousness on admission and ventilatory settings had no influence on outcome. CONCLUSIONS: With a nurse-driven NIV protocol, the intubation rate was reduced to 15% in patients receiving NIV for AHRF, with a mortality rate of only 5%. Whereas the risk of NIV failure is associated with hypoxemia and acidosis after initiation of NIV, it is also markedly influenced by the presence or absence of an underlying chronic respiratory disease.
