PHILADELPHIA – A nurse- and respiratory therapist–led opt-out protocol for coordinated daily spontaneous awakening trials and spontaneous breathing trials was associated with significant reductions in hospital length of stay and ventilator-associated events in a multicenter quality improvement collaborative nested within a prospective study of ventilator-associated events.
The protocol led to significant increases – after adjustment for age, sex, Sequential Organ Failure Assessment score , reason for intubation, comorbidity score, and unit ID – in spontaneous awakening trials (SATs), spontaneous breathing trials (SBTs), and in the percentage of SBTs performed without sedation among 3,425 episodes and 22,991days of mechanical ventilation in the collaborative units, Dr. Deverick Anderson of Duke University Medical Center, Durham, N.C., reported at an annual scientific meeting on infectious diseases.
The SAT performance rate increased from 30% to 70% during the course of the study, and the SBT performance rate also increased, though more modestly, from about 55% to nearly 70%. The performance rate of SBTs performed with sedatives off – an intervention that improves the ability to be extubated – increased from nearly 55% to more than 95%.
The mean duration of mechanical ventilation decreased by 2.4 days, mean ICU stay decreased by 3 days, and mean hospital length of stay decreased by 6.3 days, Dr. Anderson said at the combined annual meetings of the Infectious Diseases Society of America, the Society for Healthcare Epidemiology of America, the HIV Medicine Association, and the Pediatric Infectious Diseases Society.
Further, ventilator-associated conditions and infection-related ventilator-associated complications significantly decreased (odds ratio, 0.63 and 0.35, respectively). However, there was no decrease in possible or probable pneumonia (OR, 0.51).
Self-extubations increased (OR, 2.1, but there was no change in reintubations within 24 hours (OR, 0.96), Dr. Anderson said
“When we put all of this together, we were able to show a decrease in our rates of VAEs [ventilator-associated events] per 100 episodes. Over the course of the entire study, we calculated a 37% decrease in the risk of VAEs,” Dr. Anderson said.
However, the number of VAEs per 1,000 days didn’t change, because both the denominator and the numerator changed with the intervention. This finding raises questions about determining the right denominator to use. Based on the findings, it appears that ventilator episodes, rather than ventilator days, might be the best denominators, he said.
The study was conducted at 12 adult intensive care units at seven hospitals participating in the Centers for Disease Control and Prevention’s Prevention Epicenters Wake Up and Breathe Collaborative between November 2011 and May 2013. The collaborative was designed to prevent VAEs by decreasing patients’ sedative and ventilator exposures.
The collaborative was developed after early 2013 when the CDC replaced its ventilator-associated pneumonia (VAP) definitions with VAE definitions, expanding surveillance to VAEs in an effort to improve the objectivity of the definitions, to improve the ease of performing surveillance, and to try to improve the ability to make interhospital comparisons, Dr. Anderson explained, adding that VAEs include VAP, but also include pulmonary edema, atelectasis, and acute respiratory distress syndrome.
Thus, interventions aimed simply at reducing VAP may not change the rate of VAEs, he said.
Patients with VAEs stay on ventilators longer, stay in the ICU longer, are exposed to more antibiotic, and have two- to threefold increased rates of mortality, compared with those on ventilators but without VAEs, but little is known about preventing VAEs.
A larger study suggested that about a third of cases might be preventable, but no intervention has been tested and found to have an effect on the rate of VAEs. The Wake Up and Breathe Collaborative was tasked with answering the question of whether VAEs are preventable, and the investigators thought the best opportunity for prevention was to decrease the amount of sedation that ventilated patients received, Dr. Anderson said.
“More specifically – to decrease sedation through daily SATs and SBTs,” he added.
The opt-out protocol called for SATs and SBTs in all ventilated patients unless they met specific safety criteria or a physician wrote a specific opt-out order.
Though limited by the quasi-experimental open label study design, the findings are consistent with those from prior studies of such protocols.
“We felt that our multicenter prospective collaborative study was a success. … putting it all together, we conclude that VAEs are preventable when we improve compliance with evidence-based practice for our ventilated patients,” he said.Dr. Anderson reported receiving royalties from UpToDate and receiving research support from the CDC and the National Institutes of Health/National Institute of Allergy and Infectious Diseases.