Retrospective analysis of the risk factors and pathogens associated with early-onset ventilator-associated pneumonia in surgical-ICU head-trauma patients.

BACKGROUND: Early-onset ventilator associated pneumonia (EOVAP) are frequent in head-trauma patients, but specific risk factors are poorly studied in this population. METHODS: We conducted a retrospective cohort study in a surgical intensive care unit. Consecutive severe head-trauma patients admitted from January 2000 to December 2002 were studied. Microorganisms, and risks factors for EOVAP were analyzed. RESULTS: During the 3-year period, 161 patients were studied; 21.1% of them developed an EOVAP. On univariate analysis 6 variables were associated with EOVAP: early enteral feeding, barbiturate use, immunosuppression, mean Simplified Acute Physiology Score 2, acute respiratory distress syndrome, and initial neurosurgery procedures. On multivariate analysis, enteral feeding >2000 Kcal before day 5 [odds ratio (OR): 0.33, 95% confidence interval (CI): 0.21-0.85] and initial neurosurgical procedure (OR: 0.36, 95% CI: 0.15-0.89) remained protective factors for EOVAP, whereas immunosuppression (OR: 7.15, 95% CI: 1.66-30.73) and barbiturate use (OR: 2.68, 95% CI: 1.06-6.80) remained risk factors for EOVAP. EOVAP was also significantly associated with a longer duration of mechanical ventilation (14.0 vs. 11.0 d, P=0.024), and a longer sedation duration (8.3 vs. 5.8 d P=0.005). Methicillin-susceptible Staphylococcus aureus was the most common pathogen involved in EOVAP (46%). CONCLUSIONS: We demonstrate for the first time that early enteral feeding is a protective factor for EOVAP, and this result could have clinical implications for the prevention of EOVAP after traumatic brain injury. This study also confirms that barbiturate use is an important risk factor of EOVAP whereas Methicillin-susceptible S. aureus was found to be the main pathogen involved in EOVAP.

Computed tomography scanning of the sciatic nerve posterior to the femur: Practical implications for the lateral midfemoral block.

BACKGROUND AND OBJECTIVES: Using computed tomography (CT) scans of the thighs, this study addresses sciatic nerve anatomy at the injection site for the lateral midfemoral sciatic nerve block. It addresses the recommendation of neutral leg rotation to facilitate block placement. METHOD: This prospective and descriptive study involves 21 patients scheduled for CT scan imaging of the lower limbs. Transverse CT scans were analyzed at 20, 25, and 30 cm distal to the upper border of the greater trochanter (GT) of the femur with the knee externally rotated by 30 degrees. The angle alpha formed by the broad axis of the sciatic nerve and the coronal plane, skin-to-nerve distance, great vessel-to-nerve distance, division of the sciatic nerve, and widths of the perineural space were assessed. Values are expressed as mean +/- SD. RESULTS: At 20, 25, and 30 cm distal to the GT, the alpha angle was 50 degrees +/- 14 degrees, 55 degrees +/- 13 degrees, and 56 degrees +/- 26 degrees, respectively. This angle increased to nearly 90 degrees when the knee was rotated to a neutral position. The skin-to-nerve distance was 5.9 +/- 1.1 cm, 5.4 +/- 0.9 cm, and 5.7 +/- 1.1 cm. The section width of the perineural space was 1.8 +/- 0.9 cm(2), 3.9 +/- 2 cm(2), and 5.6 +/- 2.4 cm(2). The sciatic nerve was divided in 27% of subjects at 20 cm and in 90% at 30 cm distal. CONCLUSION: The characteristics of sciatic nerve anatomy described in this study support observations and clinical recommendations regarding lateral midfemoral sciatic nerve block.