HIV and hepatitis B seroprevalence in trauma patients in North Central Nigeria.

BACKGROUND: With the high prevalence rate of HIV and Hepatitis B virus infections in sub-Saharan Africa, infected surgical patients, especially those with fresh open wounds, pose significant danger of occupationally-acquired infections to health workers. METHOD: A two-year double blind study aimed at determining the seroprevalence rates of HIV and Hepatitis B virus infections among trauma patients with fresh open wounds in North Central Nigeria. RESULTS: There were 134 patients with fresh open wounds in this study; their ages ranged between 17-80 years with a mean of 30.9 +/-9.6 years and the male:female ratio was 5:1. All the patients were tested for both HIV and Hepatitis B virus infections. Six(4.5%) patients were positive for HIV-1 while 95(70.9%) patients were positive for Hepatitis B. In all, 3(2.2%) male and 3(2.2%) female patients tested positive for HIV-1 while 77(57.4%) males and 18(13.4%) females tested positive for Hepatitis B; 5(3.7%) patients tested positive for both HIV and Hepatitis B. Though every social class was represented, HIV infection rate was higher in Social Class V than in Social Class 1 but the class incidence rate for Hepatitis B was about the same ranging between 1.2 and 1.6 for both the upper and lower classes. The significance of this study was that the incidence of Hepatitis B virus infection in trauma patients was remarkably higher than the incidence of HIV infection. The implication is that emphasis on control of exposure of health care workers to blood borne infections in the workplace should be as strong for Hepatitis B virus infection as it is for HIV. CONCLUSION: The main finding of this study was the determination of the seroprevalence of HIV and Hepatitis B virus infections in trauma patients with open wounds which underpinned the dangers they pose to health care workers.

Comparison of end-tidal carbon dioxide, oxygen saturation and clinical signs for the detection of oesophageal intubation.

The reliability of various methods for detecting oesophageal intubation was assessed by means of a single blind study in rats. Both oesophagus and trachea were simultaneously intubated. The presence or absence of various clinical signs was noted during tracheal or oesophageal ventilation and arterial blood gases and end-tidal CO2 were measured. Oesophageal ventilation for one minute was associated with significant decreases (P less than 0.001) in pH, PaO2 and SaO2 and a significant (P less than 0.001) increase in PaCO2. Although mean PaO2 decreased by 70 per cent and mean SaO2 decreased by 31 per cent, 43 percent of rats failed to demonstrate a decrease in SaO2 below 85 per cent. Oxygen saturation was the least reliable method for detecting oesophageal intubation (sensitivity = 0.5, specificity = 0.9, positive predictive value (PPV) = 0.8). Chest movement was the most reliable clinical sign for detecting oesophageal intubation (sensitivity = 0.9, specificity = 1.0, PPV = 1.0). Oesophageal rattle was the second most reliable clinical sign (PPV = 0.9). Moisture condensation in the tracheal tube (PPV = 1.0) and abdominal distension (PPV = 0.9) were judged to be the least reliable because each had a high false negative rate of 0.3. The most reliable method for the early detection of oesophageal intubation in rats was end-tidal, CO2 (sensitivity 1.0, specificity = 1.0, PPV = 1.0). In addition, end-tidal CO2 when used in conjunction with the four clinical signs improved the reliability of these signs.

Method for noninvasive determination of arterial PCO2 in anesthetized rats.

A method for the noninvasive determination of arterial PCO2 in mechanically ventilated rats is presented. In normotensive, rats under steady state conditions where a depth of anesthesia adequate to abolish spontaneous ventilatory effort was used, end-tidal CO2 and arterial PCO2 were highly correlated (r = 0.96; p less than 0.001). The regression equation for this relationship was: PaCO2 (mmHg) = 6.757 +/- 8.984 ETCO2(%). This method obviates the need for arterial cannulation and may be useful in neuropharmacological research in rats when knowledge of arterial CO2 alone is required.

Failure of nimodipine to reverse acute experimental spinal cord injury.

The calcium-channel blocking agent, nimodipine, was administered to cats for 5 days after acute experimental SCI. Six weeks after injury, no significant differences in neurologic recovery or white matter tissue preservation at the injury site were found between treated and control animals.

Therapeutic trial of hypercarbia and hypocarbia in acute experimental spinal cord injury.

Hypocarbia, normocarbia, or hypercarbia was maintained for an 8-hour period beginning 30 minutes after acute threshold spinal cord injuries in cats. No statistically significant differences in neurological recovery or histologically assessed tissue preservation were found among the three groups of animals 6 weeks after injury. No animal recovered the ability to walk. It is concluded that maintenance of hypercarbia or hypocarbia during the early postinjury period is no more therapeutic than maintenance of normocarbia. Mortality rates and tissue preservation data suggest, however, that postinjury hypocarbia may be less damaging than hypercarbia.

Failure of tetracaine to reverse spinal cord injury in the cat.

Beginning 30 minutes after acute spinal cord injury, cats were treated by the administration of continuous spinal anesthesia for 8 hours. This was achieved by the intermittent injection of hyperbaric tetracaine into the subarachnoid space at the site of injury via an indwelling catheter. There were no significant differences in functional recovery or histologically assessed tissue preservation between treated cats and concurrently managed control animals. The indwelling subarachnoid catheter used for drug administration was found to have no significant effect on the spinal cord injury.

A reproducible spinal cord injury model in the cat.

Allen's weight-drop method for producing experimental spinal cord injuries was improved by placing a curved stainless steel plate anterior to the spinal cord to provide a smooth, hard surface for the receipt of posterior cord impact. In addition, an electronic circuit was used to ensure that cord injury was produced by a single impact, thereby enhancing the reproducibility of the injury mechanism. Using a spinal cord injury model with these modifications, the author found that the recovery of hindlimb function and the histopathological appearance of the injured cord 6 weeks after upper lumbar injury were closely related to injury magnitude. The curve of functional recovery versus injury magnitude has a sharp transition centered at 10 gm X 15 cm, and indicates that an injury of 10 gm X 20 cm produces a "threshold" lesion suitable for the future evaluation of spinal cord treatment methods.

Confirming tracheal intubation - a simple manoeuvre.

A simple technique is described for confirming oral tracheal intubation carried out under direct laryngoscopy. With the laryngoscope blade still in the mouth following intubation, posterior displacement of the tracheal tube towards the palate will usually bring the tube and vocal cords into direct view, providing confirmation of correct tube placement. In 50 consecutive oral tracheal intubations, the tube was seen to pass between the vocal cords in 29 cases, confirming correct tube placement. In the remaining 21 cases, the larynx was obscured during intubation. Posterior displacement of the tube confirmed correct placement in all 21 cases.