Treatment of multidrug-resistant Acinetobacter baumannii ventilator-associated pneumonia (VAP) with intravenous colistin: a comparison with imipenem-susceptible VAP.

We prospectively evaluated the efficacy and toxicity of intravenously administered colistin in 35 episodes of ventilator-associated pneumonia (VAP) due to multidrug-resistant Acinetobacter baumannii. Microbiological diagnosis was performed with use of quantitative culture. In 21 patients, the episodes were caused by a strain susceptible exclusively to colistin (the CO group) and were all treated with this antimicrobial intravenously. In 14 patients, the episodes were caused by strains that remained susceptible to imipenem and were treated with imipenem-cilastatin (the IM group). Acute Physiology and Chronic Health Evaluation II scores at the time of admission and Sequential Organ Failure Assessment scores at time of diagnosis were similar in both groups. VAP was considered clinically cured in 57% of cases in both groups. In-hospital mortality rates were 61.9% in the CO group and 64.2% in the IM group, and the VAP-related mortality rates were 38% and 35.7%, respectively. Four patients in the CO group and 6 in the IM group developed renal failure. Neurophysiological evaluation was performed during 12 episodes in the CO group, but it revealed no signs of neuromuscular blockade. Intravenous colistin appears to be a safe and effective alternative to imipenem for the management of VAP due to carbapenem-resistant strains of A. baumannii.

Critical illness polyneuropathy: risk factors and clinical consequences. A cohort study in septic patients.

OBJECTIVE: To determine risk factors and clinical consequences of critical illness polyneuropathy (CIP) evaluated by the impact on duration of mechanical ventilation, length of stay and mortality. DESIGN: Inception cohort study. SETTING: Intensive care unit of a tertiary hospital. PATIENTS: Septic patients with multiple organ dysfunction syndrome requiring mechanical ventilation and without previous history of polyneuropathy. INTERVENTIONS: Patients underwent two scheduled electrophysiologic studies (EPS): on the 10th and 21st days after the onset of mechanical ventilation. RESULTS: Eighty-two patients were enrolled, although nine of them were not analyzed. Forty-six of the 73 patients presented CIP on the first EPS and 4 other subjects were diagnosed with CIP on the second evaluation. The APACHE II scores of patients with and without CIP were similar on admission and on the day of the first EPS. However, days of mechanical ventilation [32.3 (21.1) versus 18.5 (5.8); p=0.002], length of ICU and hospital stay in patients discharged alive from the ICU as well as in-hospital mortality were greater in patients with CIP (42/50, 84% versus 13/23, 56.5%; p=0.01). After multivariate analysis, independent risk factors were hyperosmolality [odds ratio (OR) 4.8; 95% confidence intervals (95% CI) 1.05-24.38; p=0.046], parenteral nutrition (OR 5.11; 95% CI 1.14-22.88; p=0.02), use of neuromuscular blocking agents (OR 16.32; 95% CI 1.34-199; p=0.0008) and neurologic failure (GCS below 10) (OR 24.02; 95% CI 3.68-156.7; p<0.001), while patients with renal replacement therapy had a lower risk for CIP development (OR 0.02; 95% CI 0.05-0.15; p<0.001). By multivariate analysis, CIP (OR 7.11; 95% CI 1.54-32.75; p<0.007), age over 60 years (OR 9.07; 95% CI 2.02-40.68; p<0.002) and the worst renal SOFA (OR 2.18; 95% CI 1.27-3.74; p<0.002) were independent predictors of in-hospital mortality. CONCLUSIONS: CIP is associated with increased duration of mechanical ventilation and in-hospital mortality. Hyperosmolality, parenteral nutrition, non-depolarizing neuromuscular blockers and neurologic failure can favor CIP development.

[Abdominal respiratory muscle activity in patients with stable chronic obstructive pulmonary disease]. / Actividad de la musculatura espiratoria abdominal en pacientes con enfermedad pulmonar obstructiva crónica estable.

With the purpose of defining the pattern of abdominal respiratory muscle activity in patients with chronic obstructive pulmonary disease (COPD), we studied the electromyogram of the rectus abdominis (RA), the external oblique (EO) and transversus (TM) muscles in 14 patients with different degrees of airways obstruction (FEV1: 41 +/- 12%; FEV1/FVC: 45 +/- 10%; RV: 198 +/- 38%; PaO2: 75.8 +/- 12 y PaCO2: 41.4 +/- 5.7 mmHg). The EMG was obtained by insertion of bipolar electrodes guided by an ultrasound image of the abdominal wall to locate the position of the muscles. The measurements were recorded in supine decubitus position in 5 situations: a) breathing at tidal volume; b) slow expiration until RV; c) with inspiratory load; d) with expiratory load, and e) during relaxed breathing with the arms raised. Recordings were also made in the same situations with 10 patients sitting. Eight patients presented phasic expiratory activity during relaxed breathing (TM activity alone or accompanied by EO). We found no significant differences in degree of hyperinflation or in arterial gases between patients with phasic expiratory activity and those without. There were significant differences between these 2 groups, however, as to degree of airways obstruction, for absolute values of FEV1 (p < 0.02) and in raw values (p < 0.04). Slow breathing until RV recruited muscular activity in 13 patients; the muscles did not operate in unison, however, with TM acting first. Recruitment was also observed when inspiratory and expiratory loads were placed, although in this case the 3 muscles acted simultaneously. Phasic activity was observed in only 2 patients for recordings made with arms raised, at which time there was greater tonic muscle activity. The phasic activity pattern recorded when patients were sitting was very similar to that obtained in supine position. In summary, some patients with stable COPD have phasic expiratory activity of the abdominal muscles when resting. These muscles do not appear to act as a unit and this phasic expiratory activity is related to severity of upper airways obstruction.