PT OT reduces ICU delirium
- related: ICU intensive care unit
- tags: #literature #pulmonary
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Delirium is the most common acute brain dysfunction seen in critically ill patients and is highly associated with poor outcomes. It can, in and of itself, complicate ICU management. Interestingly, in one randomized controlled trial, patients who were provided early physical and occupational therapy (PT/OT), started at the time of intubation, exhibited significantly less delirium than patients receiving routine physical and occupational therapy, typically delayed until the time of extubation.
Delirium is estimated to affect 50-75% of adult patients undergoing mechanical ventilation and has been associated with higher mortality, longer periods of mechanical ventilation and hospital stay, higher costs, and long-term cognitive impairment. Tools for assessing delirium, such as the Confusion Assessment Method-ICU (CAM-ICU) are now widely employed in many ICUs.
In a number of randomized trials, the incidence of delirium has been associated with exposure to benzodiazepines, and many ICUs now have shifted sedation regimens away from this class of drugs when possible. Despite this shift, delirium remains common, and there is interest in other methods to decrease its incidence and perhaps beneficially effect adverse outcomes associated with delirium. In a trial assessing the use of PT/OT in patients with respiratory failure, investigators showed that this intervention returns more patients to functional independence at the time of hospital discharge when compared with a traditional approach of liberating the patient from mechanical ventilation first and then instituting therapy. The patients in this trial were assessed daily with the CAM-ICU, and a significant reduction in days of delirium was seen in the patients with early PT/OT. Interestingly, this difference did not seem to relate to the total amount of sedative exposure since it was not different between the groups. Rather, it might relate to the benefits of more intensive cognitive interaction that occurs during communications between therapist and patient. This observation is encouraging in the sense that shaping the environment of the ICU may have salutary effects on frequently acquired complications, such as delirium. One might also reason that shaping the ICU environment to enhance the quality of sleep (which appears significantly disturbed by both critical illness as well as the ICU environment) could have many beneficial effects; however, to date, no measures in the ICU directed at establishing more normal diurnal rhythmicity has been shown to improve the incidence of delirium.
In the past, pharmacologic interventions to prevent delirium have been thought to carry possible benefits, but recent randomized trials have been disappointing. In one trial enrolling more than 1,700 patients in 21 ICUs who were anticipated to require ICU care for more than 48 hours, the patients were randomized to receive either low-dose haloperidol or placebo. The trial was stopped early for futility; no difference in mortality, length of mechanical ventilation, or incidence of delirium was seen (choice A is incorrect). Another recent trial randomized patients with acute respiratory failure and/or shock to placebo, low-dose haloperidol, or low-dose ziprasidone, an atypical antipsychotic medication. Again, there was no difference in the number of days of delirium or coma seen during the intervention period (choice B is incorrect). Based on these results, there is little reason to treat patients with these medications as a prophylactic measure to protect against the development of delirium.1
Both sleep disruption and delirium are very common in ICU patients, especially patients requiring mechanical ventilation. While it is known that sleep deprivation in normal subjects and patients who are not critically ill impacts respiratory, endocrine, immune, and cognitive function, it is not clear if causal pathways connect sleep disturbance to delirium or vice versa in the ICU or whether environmental and drug exposures in the ICU drive both. All of these causal pathways may coexist. While many studies have focused on ICU exposures associated with delirium and disturbances of sleep, including interventional trials, the most compelling interventions that improve sleep quality and decrease the incidence of delirium have implemented multifactorial and coordinated bundled care that minimizes drug exposures, reduces sounds disturbing sleep, limits patient procedures and care during sleep periods, and attempts to restore more normal light–dark cycling in the room (choice D is correct).
Although some studies have suggested total sleep time in the ICU is only slightly reduced, all investigations have shown sleep in this environment to be highly disrupted, occurring in short periods throughout the day and night. In many patients undergoing mechanical ventilation, sleep architecture is so distorted that more than 80% of recorded polysomnograms cannot be scored by the usual criteria. Common features of the polysomnogram are reduced K complexes and sleep spindles and reduced or absent stage 3 non–rapid eye movement (NREM) and rapid eye movement (REM) sleep. Several investigations have demonstrated mean noise levels in the ICU well in excess of Environmental Protection Agency recommendations of both day and night sound exposure. Other investigations have documented dozens of sleep interruptions at night related to performance of procedures, bathing, wound care, phlebotomy, and obtaining vital signs. In addition, light exposure in the ICU may exceed typical office levels and are of an intensity known to alter circadian rhythm. Many of these environmental factors can be modified to promote more normal sleep architecture.
Research has also identified medications routinely used for sedation in the ICU to be associated with delirium and sleep disruption. Benzodiazepines are known to increase early-stage sleep and to reduce stage 3 NREM sleep and in comparison with other sedating agents (primarily propofol and dexmedetomidine) to be associated with much higher incidences of delirium (choice A is incorrect). Benzodiazepines should be avoided as first-line therapy for sedation of mechanically ventilated patients. By comparison with benzodiazepines, propofol is associated with a lower incidence of delirium, although it suppresses REM sleep (choice C is incorrect). Dexmedetomidine, an α-agonist, has gained widespread use for the sedation of mechanically ventilated patients, and it is associated with less delirium when compared with benzodiazepines. In one randomized placebo-controlled trial, dexmedetomidine given at a low dose nocturnally was associated with a decreased incidence of delirium. In some studies, dexmedetomidine infusion has been shown to increase NREM sleep.
A number of studies have evaluated the addition of specific pharmacologic agents to enhance sleep, reduce delirium, or both. Both typical (haloperidol) and atypical (risperidone, olanzapine, quetiapine) antipsychotics have been studied to reduce delirium and have been shown to be ineffective for this purpose. Haloperidol does increase stage 3 NREM sleep (choice B is incorrect). Melatonin and a melatonin receptor agonist (ramelteon) have been studied in critically ill patients, with variable effects on sleep and duration of delirium. Conclusions regarding these interventions have been limited by the relatively small size of published trials, but several large multicenter trials are underway.