Literature Updates from July 2015

Sedation Options for the Morbidly Obese Intensive Care Unit Patient: A Concise Survey and an Agenda for Development

Morbidly obese patients have been increasing its presence in the operating room as patients because of surgical treatment of its condition. These kinds of patients require often critical care and pose several problems related to their management. Sedation technique is one of the aspects that should be considered because of characteristics. The recommended review points out some important points that should be taken care of when dealing with morbidly obese patients in the critical care setting.

Sleep Deprivation Does Not Affect Neuronal Susceptibility to Mild Traumatic Brain Injury in the Rat

Mild and moderate traumatic brain injuries (TBIs) (and concussion) occur frequently as a result of falls, automobile accidents, and sporting activities, and are a major cause of acute and chronic disability. Fatigue and excessive sleepiness are associated with increased risk of accidents, but it is unknown whether prior sleep debt also affects the pathophysiological outcome of concussive injury. The authors found that mild TBI caused significantly higher DN densities (0.76%), and this was unchanged by preexisting acute or chronic sleep debt (TSD, 0.23%; CSR, 0.7%). Thus, although sleep debt may be predicted to increase the incidence of concussive injury, the present data suggest that sleep debt does not exacerbate the resulting neuronal damage.

Immune Cell Expression of GABAA Receptors and the Effects of Diazepam on Influenza Infection

There is some controversy regarding the effects of using benzodiazepines as sedative agents in critical patients. Previous work has proven that the outcomes are worse as compared to the use of dexmedetomidine regarding length of intubation, length of stay. Other authors have shown an increased incidence of infectious complications, pneumonia, in patients under benzodiazepine sedation. The present paper shows evidence that the expression of GABA A receptors in immune cells is directly related to an increase of duration of influenza infection.

Melatonin is Required for the Circadian Regulation of Sleep

The use of melatonin is controversial as a sleep/circadian rhythm therapeutic. This paper uses the genetic knockout of arylalkylamineN-acetyltransferase 2 (required for melatonin synthesis) in zebrafish to elucidate the role of melatonin in sleep regulation. Zebrafish mutants that lack melatonin have significantly longer latency to sleep and shorter sleep bouts than wild-type fish. In the absence of circadian cues the circadian regulation of sleep is abolished, yet other behavioral and molecular circadian rhythms are maintained. Taken together, these experiments show that melatonin functions downstream of the central circadian pacemakers to promote the timing of and maintenance of sleep in this model system.

Shift Work in Rats Results in Increased Inflammatory Response After Lipopolysaccharide Administration: A Role for Food Consumption

This paper is further evidence that the timing of food around circadian and sleep disruption is relevant to circadian re-entrainment and related processes like inflammation. Using a model of shift work where rats were kept awake for 10 hours during their normal rest period, and then injected with LPS at two time points, the animals that were forced to do “shift work” generated higher levels of inflammation. If food was taken away from the rats during the time of their shift work, the resulting hyper-inflammation was reduced to that of control rats. To further their case, if food was made available only during the normal inactive phase for rats (lights-on period), thus forcing the rats to forage while they may have otherwise been resting caused hyper-inflammation after LPS exposure. These data suggest the importance of the timing of food intake to circadian homeostasis and links circadian disruption, metabolism, and inflammation.

Effects of Earplugs and Eye Masks Combined with Relaxing Music on Sleep, Melatonin and Cortisol Levels in ICU Patients: A Randomized Controlled Trial

In this study, the authors aimed to determine the effects of using earplugs and eye masks with relaxing background music on sleep, melatonin and cortisol levels in actual ICU patients. 50 cardiac ICU patients were randomized to sleep with or without earplugs and eye masks combined with 30-minute relaxing music during the postoperative nights in cardiac ICU. Perceived sleep quality was better in the intervention group. There were no group differences found in measuring urinary melatonin levels and cortisol levels for the night before surgery, and the first and second night post-surgery.

Melatonin Reduces the Need for Sedation in ICU Patients: A Randomized Controlled Trial

In this single center, double blind randomized placebo-controlled study, the authors sought to determine if nocturnal melatonin supplementation would reduce the need for sedation in critically ill patients. The authors discovered that melatonin treated patients received less sedation. Other neurological indicators (amount of some neuroactive drugs, pain, agitation, anxiety, sleep observed by nurses, need for restraints, need for extra sedation, nurse evaluation of sedation adequacy) seemed improved. Unfortunately ICU related PTSD did not seem get better with treatment.

Emerging Role of Melatonin and Melatonin Receptor Agonists in Sleep and Delirium in Intensive Care Unit Patients

In this review, the authors sought to investigate the impact of melatonin and melatonin receptor agonist on delirium prevention. The authors acknowledge the limitations of our understanding on what causes delirium but postulate that sleep deprivation plays a role. This is a timely and good review of the literature on the relationship between melatonin, sleep deprivation and delirium.

Sleep in the Neurological Intensive Care Unit: Feasibility of Quantifying Sleep After Melatonin Supplementation with Environmental Light and Noise Reduction

It is widely known that sleep deprivation can be detrimental to critically ill patients. In this investigation, the authors sought to determine the feasibility of quantifying sleep in 12 neurological ICU patients who had received melatonin. Patients were also subjected to light and environmental noise reduction. Like many previous studies, the authors found it hard to quantify sleep in ICU patients. Additionally, the authors discovered that total sleep time was normal, although sleep was fragmented and time spent in slow-wave or rapid eye movement sleep was notably decreased as has been discovered in many other studies. Unfortunately, the authors did not find a difference between the control and intervention group

The Use of Modafinil in the Intensive Care Unit

In this small case series, the authors address a several issues related to sleep deprivation in the ICU, namely fatigue, depression and excessive daytime somnolence. The investigators sought to determine the use of modafinil, a psycho-stimulant, could improve ICU outcomes by treating some of these conditions. They discovered that through the use of modafinil 200mg each morning patient had greater wakefulness, were able to participate in rehab more and got more sleep at night. This study will need to be repeated on a larger scale to help determine if modafinil can have a true impact on ICU outcomes.