July 2007

Section Input Drives AARC Congress
The 2007 AARC International Respiratory Congress may still be several months away – this December 1-4 in Orlando, FL – but it’s not too soon to begin making plans to attend. And as a Specialty Section member, you have even more reason to register for the meeting, because much of what you’ll see on the Final Program will have come directly from your peers. Every year the sections recommend topics for the Congress, and most end up on the agenda, in the form of lectures and symposia geared directly to your special interests and concerns. LEARN MORE

S/F Ratio Can Replace P/F Ratio in Assessing Hypoxemia in ALI/ARDS
A new study in the June 15 Epub edition of CHEST finds the SpO2/FiO2 (S/F) ratio can be substituted for the more commonly used PaO2/FiO2 (P/F) ratio in assessing degree of hypoxemia in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Investigators used data on patients who participated in the ARDS Network trial to arrive at their conclusions. The relationship between S/F and P/F was described by the equation: S/F = 64 + 0.84*(P/F). An S/F value of 235 corresponded with a P/F ratio of 200, while an S/F value of 315 corresponded with a P/F ratio of 300. The S/F threshold values of 235 and 315 resulted in 85% sensitivity/85% specificity, and 91% sensitivity/56% specificity for the P/F values of 200 and 300, respectively. READ ABSTRACT

NIV-Specific Modes Perform Differently
Swiss researchers who conducted a bench study to evaluate leaks at the patient-ventilator interface during the application of noninvasive ventilation (NIV) using eight different ICU ventilators find leaks are common and lead to an increase in trigger delay and workload, a decrease in pressurization, and delayed cycling. Most ventilators with an NIV mode were able to at least partly compensate for these problems, but a wide variation in efficacy was noted between the different machines. The authors conclude, “Clinicians should be aware of these differences when applying NIV with an ICU ventilator.” The study appeared in the June 12 Epub edition of Intensive Care Medicine. READ ABSTRACT

Isolation Rooms Come Up Short
Your hospital’s airborne infection isolation rooms (AIIRs) may not be getting the job done, report researchers publishing in the June issue of the American Journal of Infection Control. They tested 678 AIIRs across the country to see how well they were stopping the spread of disease-bearing particles. Just 32% of the rooms achieved the recommended pressure differential between the isolation rooms and adjacent areas, although rooms with solid ceilings performed significantly better than rooms with dropped ceilings. Isolation room ultrafine particle concentrations were more highly correlated with particle levels in surrounding areas than in the ventilation systems serving the rooms, and nearly all of the ventilation filters serving AIIRs collected fewer particles than anticipated. READ ABSTRACT

Study Identifies Degree of Lung Injury in ARDS
Noting current American-European Consensus Conference (AECC) definitions for ALI and ARDS lack standardization for measuring the oxygenation defect, Spanish researchers tested early assessment of oxygenation on specific ventilator settings to see if they could identify patients with established ARDS. The study was conducted among 170 patients meeting ARDS criteria of a PaO2/FiO2 128+/-33 mmHg. The standard ventilator settings that best identified established ARDS patients and predicted differences in ICU mortality were PEEP>/=10 cmH2O and FiO2>/=0.5 at Day 1. On these settings:

• 99 patients continued to meet ARDS criteria (PaO2/FiO2 155.8 +/- 29.8 mmHg, ICU mortality 45.5%)
• 55 patients were reclassified as ALI (PaO2/FiO2 246.5 +/- 25.6 mmHg, ICU mortality 20%)
• 16 patients were reclassified as acute respiratory failure (PaO2/FiO2 370 +/- 54 mmHg, ICU mortality 6.3%)

The authors believe these findings could be useful in selecting patients for clinical trials. They conclude, “Patients meeting current AECC ARDS criteria may have highly variable levels of lung injury and outcomes. A systematic method of assessing severity of lung injury is required for enrollment of ARDS patients into randomized controlled trials.” The research appeared in the June 21 Epub edition of the American Journal of Respiratory and Critical Care Medicine. READ ABSTRACT