Rapid automated microscopy for microbiological surveillance of ventilator-associated pneumonia.

RATIONALE: Diagnosis of ventilator-associated pneumonia (VAP) is imprecise. OBJECTIVES: To (1) determine whether alternate-day surveillance mini-bronchoalveolar lavage (mini-BAL) in ventilated adults could reduce time to initiation of targeted treatment and (2) evaluate the potential for automated microscopy to reduce analysis time. METHODS: Adult intensive care unit patients who were anticipated to require ventilation for at least a further 48 hours were included. Mini-BALs were processed for identification, quantitation, and antibiotic susceptibility, using (1) clinical culture (50 ± 7 h) and (2) automated microscopy (∼5 h plus offline analysis). MEASUREMENTS AND MAIN RESULTS: Seventy-seven mini-BALs were performed in 33 patients. One patient (3%) was clinically diagnosed with VAP. Of 73 paired samples, culture identified 7 containing pneumonia panel bacteria (>10(4) colony-forming units/ml) from five patients (15%) (4 Staphylococcus aureus [3 methicillin-resistant S. aureus], 2 Stenotrophomonas maltophilia, 1 Klebsiella pneumoniae) and resulted in antimicrobial changes/additions to two of five (40%) of those patients. Microscopy identified 7 of 7 microbiologically positive organisms and 64 of 66 negative samples compared with culture. Antimicrobial responses were concordant in four of five comparisons. Antimicrobial changes/additions would have occurred in three of seven microscopy-positive patients (43%) had those results been clinically available in 5 hours, including one patient diagnosed later with VAP despite negative mini-BAL cultures. CONCLUSIONS: Microbiological surveillance detected infection in patients at risk for VAP independent of clinical signs, resulting in changes to antimicrobial therapy. Automated microscopy was 100% sensitive and 97% specific for high-risk pneumonia organisms compared with clinical culturing. Rapid microscopy-based surveillance may be informative for treatment and antimicrobial stewardship in patients at risk for VAP.

Comparison of bag-valve-mask hand-sealing techniques in a simulated model.

STUDY OBJECTIVE: Bag-valve-mask ventilation remains an essential component of airway management. Rescuers continue to use both traditional 1- or 2-handed mask-face sealing techniques, as well as a newer modified 2-handed technique. We compare the efficacy of 1-handed, 2-handed, and modified 2-handed bag-valve-mask technique. METHODS: In this prospective, crossover study, health care providers performed 1-handed, 2-handed, and modified 2-handed bag-valve-mask ventilation on a standardized ventilation model. Subjects performed each technique for 5 minutes, with 3 minutes' rest between techniques. The primary outcome was expired tidal volume, defined as percentage of total possible expired tidal volume during a 5-minute bout. A specialized inline monitor measured expired tidal volume. We compared 2-handed versus modified 2-handed and 2-handed versus 1-handed techniques. RESULTS: We enrolled 52 subjects: 28 (54%) men, 32 (62%) with greater than or equal to 5 actual emergency bag-valve-mask situations. Median expired tidal volume percentage for 1-handed technique was 31% (95% confidence interval [CI] 17% to 51%); for 2-handed technique, 85% (95% CI 78% to 91%); and for modified 2-handed technique, 85% (95% CI 82% to 90%). Both 2-handed (median difference 47%; 95% CI 34% to 62%) and modified 2-handed technique (median difference 56%; 95% CI 29% to 65%) resulted in significantly higher median expired tidal volume percentages compared with 1-handed technique. The median expired tidal volume percentages between 2-handed and modified 2-handed techniques did not significantly differ from each other (median difference 0; 95% CI -2% to 2%). CONCLUSION: In a simulated model, both 2-handed mask-face sealing techniques resulted in higher ventilatory tidal volumes than 1-handed technique. Tidal volumes from 2-handed and modified 2-handed techniques did not differ. Rescuers should perform bag-valve-mask ventilation with 2-handed techniques.

Observational study of head of bed elevation adherence using a continuous monitoring system in a medical intensive care unit.

BACKGROUND: Head of bed elevation ≥ 30° reduces ventilator-associated pneumonia in mechanically ventilated patients, but adherence is variable and difficult to monitor continuously. Unlike many clinical variables, head of bed elevation is not electronically displayed or monitored with audible alarms. HYPOTHESIS: Continuous monitoring of head of bed elevation with audible alerts and visual cues when the elevation is < 30° will improve adherence by 15%. METHODS: Head of bed elevation was continuously monitored and recorded on a central monitoring station and displayed on the bedside monitor of 16 of 24 medical intensive care unit beds. Manual bedside checks were performed twice daily at varying times. RESULTS: Continuous head of bed angle was available from 98 of 313 (31%) patient beds over a 7.5 month period, representing 322 of 1,373 mechanical ventilator days (24%). Continuous monitoring was performed for 7,720 hours, 5,542 hours with the data displayed on bedside monitors and 2,178 hours with the data available only from central monitors. Head of bed elevation was ≥ 30° for 76% of the hours when the data were displayed on bedside monitors, and for 61% of hours when it was not (P < .001, odds ratio = 2.3, 95% CI 2.0-2.6). Intermittent bedside checks for head of bed elevation ≥ 30° found 97 ± 2% adherence. CONCLUSIONS: Real-time monitoring of head of bed elevation is feasible, and when combined with audible alarms and visual cues, improves ≥ 30° elevation adherence. Intermittent bedside checks over-estimate actual adherence.