The average intensive care patient spends 40% of her/his ICU time being weaned from the ventilator. Reduced weaning times means freeing up an enormous amount of floor-space, manpower and resources. Two important causes for prolonged weaning are over-hydration and excessive sedation. A study in JAMA looks at how daily sedative interruptions affect time on mechanical ventilation.
Excessive sedation has been addressed by implementing various sedation protocols. For the last decade many study protocols focused on daily interruption of sedative infusions.
An important study by Kress et al. demonstrated how time on mechanical ventilation could be reduced from 7,3 days in the control group to 4,9 days by implementing interruptions. Every day, they simply stopped sedative infusions until the patient woke up and then put the patient right back to sleep.
Unfortunately, results in subsequent trials varied and in a 2011 meta-analysis the authors concluded that – ‘With the limited data available, daily sedation interruption was not associated with a significant reduction in duration of mechanical ventilation, length of intensive care unit and hospital stay, or mortality’ . Numbers were too small. Studies were under-powered.
Patients were randomised into either standard protocol sedation (n=209) or standard protocol with daily interruptions (n=214).
Standard protocol was morphine, fentanyl or hydromorphone for analgesia and midazolam or lorazempam for sedation.
Importantly, in the standard control group they used a protocol that aimed to keep the patient as lightly sedated as possibly.
Sedation scoring systems were used hourly to ensure the patient was comfortable yet rousable state equivalent to SAS 3-4 or RASS -3-0.
In case of oversedation or to too little sedation infusion rates were changed accordingly.
In the interruption group sedation and analgesia was shut off daily. Then they waited until the patient was aroused (RASS -1 to 4) before continuing infusion at half rate then titrating back to -3 to 0.
Main outcome was time from randomisation to successful extubation. Median time to extubation was 7 days in both groups. Daily sedation did not improve time to extubation.
This contrasts with earlier studies, including the above mentioned Kress et al. Those studies, however, didn´t use a control protocol where light sedation was an active goal. The older studies probably used the old-school deep sedation until someone decided the patient was ready to be weaned.
Take home message
Implementing protocols that actively aims for light sedation is better than having no plan for sedation. There is no evidence daily interruptions adds anything to protocols for lightest possible sedation.