Effect of caffeine on the level of consciousness in critically ill patients - A randomized clinical trial

Background

Caffeine is a central nervous system stimulant alkaloid, that is found in various plants such as coffee, cocoa beans, tea leaves, guarana berries and the kola nut. It works as a non selective blocker of Adenosine receptors and has been related to the regulation of heart rate, the contraction and relaxation of cardiac and smooth muscles, and the neural signaling in the central nervous system. The use of adenosine receptor antagonists, such as caffeine, and agonists has been shown to protect against neurological diseases such as spinal cord injury, stroke, Alzheimer’s and Parkinson’s diseases.

Dose of Caffeine: Unsafe levels of intake, as noted previously, correspond to excessive levels, e.g., >100 mg/kg bw/day (more than 6000 mg/person/day) – associated with adverse effects resulting in acute caffeine toxicity. Such levels of caffeine may be achieved with abuse of over-the-counter (OTC) tablets and pure caffeine powder, but are not realistically achievable with consumption of caffeinated foods or beverages. It is clear that among the general population levels up to 600 mg/day and in some cases as much as 800 mg/day or more can be and are consumed every day with no ill-effect.

Absorption of Caffeine: Caffeine is generally accepted to be a mild stimulant. After oral ingestion of caffeine, mostly in the form of coffee or tea, 99% of it is absorbed from the gastrointestinal tract into the bloodstream, peaking 30–60 min after ingestion. Caffeine diffuses throughout the entire body; it passes all biological membranes, including the blood–brain barrier and the placental barrier.

Effect of caffeine on CVD: Based on the available evidence, caffeine consumption at a variety of intake levels, primarily in the form of tea or coffee, is generally associated with either a statistically significant decreased risk of CVD or no statistically significant relationship at all, even at intakes above 600 mg of caffeine per day. Among studies reporting a protective effect with caffeine consumption, intakes generally ranged from 100 to 400 mg per day. Several large prospective cohort studies involving caffeine intakes up to more than 600 mg/day did not report an increased risk of arrhythmia.

Uses in Stroke: Stroke occurs when blood flow to an individual’s brain is interrupted, causing cell death within the brain due to a lack of proper oxygenation. There was no statistically significant relationship between coffee and/or tea consumption at any level of consumption investigated and risk of stroke. Overall, the weight of evidence (28 out of 31 studies) suggests that there is no statistically significant association between caffeine consumption and the relative risk of stroke. Caffeine, a well-known antagonist of adenosinergic receptors, can be used effectively to modulate our mental state. Caffeine is found to be beneficial in restoring low levels of wakefulness and to counteract deteriorations in task performance related to sleep deprivation. However, the results also indicate that caffeine may produce detrimental effects on subsequent sleep, resulting in daytime sleepiness

Level of consciousness and GCS score:

Consciousness is the state of awareness of oneself and the surrounding environment and the ability to respond to external stimuli. Reduced alertness, diminished wakefulness, and a decreased awareness of oneself and the environment all characterize impaired consciousness. A coma is a profound and occasionally extended state of unconsciousness. The Glasgow Coma Scale (GCS) is a medical tool that objectively measures a coma’s severity. GCS scores are valuable in predicting the prognosis for patients with traumatic brain injuries (TBIs), subarachnoid hemorrhages, and bacterial meningitis.

Thus we have seen that caffeine is having major role as a stimulant of central nervous system, so we will conduct a study with caffeine intervention to those unconscious patients who are on enteral feed and will study if caffeine is beneficial in early improvement in their conscious level, also will check if early weaning of patients from ventilator as a secondary outcome.