Behavior of B-type natriuretic peptide during mechanical ventilation and spontaneous breathing after extubation.

BACKGROUND: The behavior of B-type natriuretic peptide (BNP) is assessed during mechanical ventilation (MV) and spontaneous breathing after extubation in critical patients. METHODS: Thirty patients admitted in the Intensive Care Unit (ICU) were enrolled. BNP, fluid balance (FB), airway pressure (AP) and dobutamine infusion needing (DP) were registered in three stages: T0, admission to ICU; T1, before extubation; T2, 24 h after extubation. RESULTS: Patients with congestive heart failure (CHF) had BNP values higher than other patients. The value of BNP during MV was greater than normal in all patients. The cut-off to discriminate patients with heart failure during MV was 286 pgxmL(-1)(sensitivity: 86%; specificity: 90%). The increase of BNP during MV directly correlated with FB and inversely correlated with AP and DP. The plasmatic level of BNP remained higher than normal values 24 h after extubation. CONCLUSIONS: The underlying disease of an ICU patient seems to play a relevant role for BNP production and is probably linked to different aspects of therapeutic approach required by the patient. Our data suggest a cut-off value of BNP higher than the usual is necessary to discriminate mechanically-ventilated patients without CHF. This study should be repeated with an enlarged population.

Correlation between hyperglycemia and mortality in a medical and surgical intensive care unit.

AIM: The aim of this study was to assess the correlation between hyperglycemia and mortality in a group of patients admitted to a medical and surgical ICU and to evaluate if the association between hyperglycemia and reason of ICU admission significantly worsens patients' outcomes. METHODS: A retrospective clinical study was conducted in the ICU of a University Hospital. Four-hundred and twelve adult patients admitted to our ICU were enrolled. The blood glucose level was measured at the time of admission and daily at 2-4 h intervals. When the glucose level exceeded 180 mg/dL, an insulin bolus or a continuous infusion were performed to maintain the glucose level at or below 180-200 mg/dL. RESULTS: Analysing the mean blood glucose levels of patients with the receiver operating characteristic (ROC) curve, it resulted that the blood glucose level of 141.7 mg/dL had higher sensitivity (76%) and specificity (56.5%) to discriminate the probability of death. In other words, in patients in whom the mean blood glucose levels were greater than 141.7 mg/dL, the probability of death was higher (26.62%) than in the group of patients in whom a strict blood glucose control was maintained (13.55%) (P = 0.0017). CONCLUSIONS: A strict blood glucose control seems to be crucial, even in a medical and surgical ICU. The need for intensive insulin therapy, even by means of continuous infusion of insulin, to obtain the normalization of blood glucose levels, appears essential.

Predictors of failure of noninvasive positive pressure ventilation in patients with acute hypoxemic respiratory failure: a multi-center study.

CONTEXT: In patients with hypoxemic acute respiratory failure (ARF), randomized studies have shown noninvasive positive pressure ventilation (NPPV) to be associated with lower rates of endotracheal intubation. In these patients, predictors of NPPV failure are not well characterized. OBJECTIVE: To investigate variables predictive of NPPV failure in patients with hypoxemic ARF. DESIGN: Prospective, multicenter cohort study. SETTING: Eight Intensive Care Units (ICU) in Europe and USA. PATIENTS: Of 5,847 patients admitted between October 1996 and December 1998, 2,770 met criteria for hypoxemic ARF. Of these, 2,416 were already intubated and 354 were eligible for the study. RESULTS: NPPV failed in 30% (108/354) of patients. The highest intubation rate was observed in patients with ARDS (51%) or community-acquired pneumonia (50%). The lowest intubation rate was observed in patients with cardiogenic pulmonary edema (10%) and pulmonary contusion (18%). Multivariate analysis identified age > 40 years (OR 1.72, 95% CI 0.92-3.23), a simplified acute physiologic score (SAPS II) > or = 35 (OR 1.81, 95% CI 1.07-3.06), the presence of ARDS or community-acquired pneumonia (OR 3.75, 95% CI 2.25-6.24), and a PaO2:FiO2 < or = 146 after 1 h of NPPV (OR 2.51, 95% CI 1.45-4.35) as factors independently associated with failure of NPPV. Patients requiring intubation had a longer duration of ICU stay ( P < 0.001), higher rates of ventilator-associated pneumonia and septic complications ( P < 0.001), and a higher ICU mortality ( P < 0.001). CONCLUSIONS: In hypoxemic ARF, NPPV can be successful in selected populations. When patients have a higher severity score, an older age, ARDS or pneumonia, or fail to improve after 1 h of treatment, the risk of failure is higher.