One of the leading causes of mortality and morbidity worldwide, traumatic brain injury (TBI) is a devastating disorder with primary injury mechanisms occurring as a result of shearing, tearing or stretching of neurons, axons, glia and blood vessels. Secondary injury mechanisms consist of disturbance in homeostasis of ions, glutamate toxicity, mitochondrial dysfunction, apoptosis and degradation of neuronal lipids in response to trauma. It results in release of inflammatory mediators and cytokines further leading to lipid peroxidation, disruption of blood–brain barrier and cerebral oedema [1].

Ventilator-associated pneumonia (VAP) is one of the most common nosocomial infections in the intensive care unit (ICU) having a high attributable mortality and results in increased length of ICU stay [2]. Early onset VAP occurs 48–96 hours after intubation and is usually associated with antibiotic-susceptible organisms whereas, Late-onset VAP occurs more than 96 hours after intubation and is commonly associated with antibiotic-resistant organisms.

TBI patients are at high risk of developing Nosocomial infections, particularly VAP, due to impaired cellular immune response and loss of consciousness [3,4]. According to the International Nosocomial Infection Control Consortium, the overall rate of VAP is 13.6 per 1000 ventilator days [5]. The incidence varies according to the patient group and hospital setting. The incidence of VAP ranges from 13–51 per 1000 ventilation days [6]. Incidence of VAP in TBI patients vary widely. The incidence has been reported to be around 36% but can go as high as 47% [7,8].

Risk factors associated with VAP are host related (comorbid conditions, level of consciousness etc), device related (indwelling tubes and ventilator circuits) and personnel related.

VAP is a common cause of development of Acute Respiratory Distress Syndrome (ARDS) in patients requiring prolonged mechanical ventilation. Numerous strategies for prevention of VAP in the form of multifaceted bundle have been used in the past [9]. Semi-recumbent position is one of the measures which is of prime importance. It reduces gastroesophageal reflux and reported to have decreased incidence of VAP than the supine position [10]. Guidelines recommend a semi‐recumbent position (30° to 45°) for preventing pulmonary complications among patients requiring mechanical ventilation. Lateral position may hinder the primary pathophysiologic mechanism of ventilator-associated pneumonia (VAP). The semi-recumbent lateral positioning could provide additional benefits as compared to semi-recumbent position, because the primary mechanism responsible for development of VAP i.e. pulmonary aspiration of oropharyngeal secretions in critically ill patients requiring mechanical ventilation, would be prevented. We have investigated whether placing patients in the semi-recumbent-lateral position would reduce the incidence of VAP and ARDS in comparison with the semi-recumbent position.