Despite obvious challenges in identifying appropriate candidates, mechanically ventilated patients can safely self-administer sedative medications using widely available infusion pumps, a research team has concluded. Although the researchers’ primary focus was not the efficacy of the patient-controlled sedation (PCS) system, they hope to delve deeper into outcomes in future studies.
“For many years, the paradigm has been that ICU patients are helpless and have no decision-making capacity, so clinicians decided what was best for the patient,” said Craig R. Weinert, MD, MPH, an associate professor of medicine at the University of Minnesota, in Minneapolis. “However, that’s probably not true. There are many ICU patients who can make care decisions.
“And with the push over the last five to seven years to have patients more alert, we tried to look at alternative types of sedative therapy, where patients may end up getting less drug. The idea here is that if we let patients give themselves their drug, the feeling that they’re managing themselves might mean they get less medication than if a nurse or physician is looking at them and interpreting their behavior. So we’re trying to change the paradigm from the doctor or nurse knowing best to maybe the patient knows best.”
To that end, Dr. Weinert, his co-investigator Linda Chlan, RN, PhD (now at Ohio State University), and their colleagues enrolled 37 informed and consenting patients into the trial. PCS dexmedetomidine was administered with a basal infusion ranging from 0.1 to 0.7 mcg/kg per hour, titrated up or down every two hours by staff nurses based on patient-triggered bolus doses (0.25 mcg/kg per dose, maximum three doses per hour). Dexmedetomidine was delivered through a standard PCS infusion pump for up to five days. The trial’s primary safety goals were to maintain heart rate above 40 beats per minute (bpm), systolic blood pressure greater than 80 mm Hg and diastolic blood pressure greater than 50 mm Hg. Feasibility was assessed by the ability to enroll eligible patients, days on PCS protocol and adherence to the titration protocol by the institution’s ICU nurses.
“This is actually the second study we’ve done,” Dr. Weinert said. “We published a smaller, nonrandomized trial several years ago (Chest 2010;138:1045-1053) where we showed that patient-controlled sedation is possible in these individuals. The current study was to see if we can do this in a randomized fashion, and for a longer time.”
The researchers reported at the 44th Critical Care Congress of the Society of Critical Care Medicine (abstract 684) that patients (60% male; mean age 52 years) were randomly assigned to receive either PCS dexmedetomidine (n=17) or usual sedation care (n=20). No patient’s heart rate fell below 40 bpm, although three PCS patients had mild hypotension necessitating rate reduction, fluid bolus or transient drug cessation.
Almost half of the PCS patients (n=7) required no supplemental sedatives. Seven others received between one and three sedative doses, while the remaining three patients received more than three doses while on the protocol. PCS patients were also satisfied and/or very satisfied with their ability to self-administer medication (92%), control anxiety (69%) or feel relaxed (62%).
“Most importantly, staff nurses—these were not research nurses—could follow the protocol for titrating the dexmedetomidine up or down based on the study algorithm,” Dr. Weinert added. “They didn’t do it perfectly, but they did it well enough that there weren’t any adverse effects from the titration protocol.” Nursing adherence was found to be 79%; safety parameter adherence was 100%. Finally, no PCS patient became delirious (as measured by the Confusion Assessment Method for the Intensive Care Unit) while on protocol; four of their counterparts undergoing usual care did.
Enrolling mechanically ventilated ICU patients into a randomized controlled trial may seem daunting, but as Dr. Weinert explained, it is feasible under the right circumstances. “There were many patients in the ICU on a ventilator who were not even eligible for the study,” he said. “They had to know what they were doing in order to press the button. So one of our feasibility questions was: ‘Are there patients awake enough to understand the study and participate in it? And we showed there are, indeed, patients who can do this.”
Given the success of the National Institutes of Health–funded trial, the researchers are submitting a grant for a follow-up study looking more specifically at patient anxiety, drug consumption and ventilator duration as outcomes. “Our goal is to improve the experience of mechanical ventilation, not to decrease sepsis, ICU mortality or length of stay. We’re here to make the experience as tolerable as possible. We want patients to be more awake, less anxious and receive less total sedative drug.”