Infectious Disease

Infection is a major cause of post-trauma morbidity and, with TBI, is a leading cause of death in patients surviving more than 3 days.^[251] Up to 20% of all deaths from trauma are due to the effects of MOSF and sepsis.^[252] Failure to promptly treat traumatic shock and reverse hypoperfusion causes an exaggerated stress response; sepsis results from failure of the immune system in the setting of the multiple infectious challenges offered by invasive intravenous access devices, mechanical ventilation, and traumatic wounds.^[253] Wound healing and repayment of the "oxygen debt" caused by hypoperfusion increase metabolic requirements. Nutritional deficiency from poor caloric intake and increased metabolic requirements slows healing and further impairs the immune system,^[254] thus emphasizing the importance of early enteral nutrition.^[255]

Mechanical ventilation is a risk factor for nosocomial pneumonia because of disruption of the barriers against infection and colonization of the patient by hospital flora. Pulmonary laceration and contusion increase the risk for pneumonia because of the presence of fluid collections and devitalized tissue within the lung. Nosocomial pneumonia accounts for approximately 15% of hospital-associated infections. ^[256] In addition to chest trauma and mechanical ventilation, TBI and the use of steroids increase the risk for nosocomial pneumonia. ^[257] Thoracoabdominal surgery increases the risk by at least threefold,^{[258] [259]} presumably because of further impairment of respiratory musculature as a result of the surgical wound, with a concomitant decrease in pulmonary reflexes from narcotic analgesics. Epidural analgesia exerts a beneficial effect on outcomes because it allows for more effective cough and a clearer mental status.^[230] Pneumonia is diagnosed in one of two ways: clinically or by invasive diagnosis. Clinical pneumonia is defined as the presence of a new pulmonary infiltrate unexplained by other obvious causes and associated with elevated temperature, purulent sputum production, or leukocytosis.^[260] One or more of these findings are common in intubated patients, which has led to a relative overdiagnosis of pneumonia by these criteria and subsequent overtreatment. Invasive diagnosis (protected specimen brushings or bronchoalveolar lavage) allows for more accurate use of antimicrobials. Less than half of a population of trauma patients suspected of having nosocomial pneumonia on clinical grounds required treatment on the basis of bronchial culture.^[261]

A number of excellent references listing specific antimicrobial therapy for trauma patients are available, but local

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