South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde
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Randomized Controlled Trial Clinical Trial
Gas exchange indices--how valid are they?
This study examined the arterial-alveolar oxygen tension difference (AaDO2), arterial oxygen tension to inspired oxygen fraction ratio (PaO2/FiO2) and alveolar to arterial oxygen tension ratio (PAO2/PaO2) with regard to: (i) their correlation with the calculated pulmonary shunt in critically ill patients; and (ii) the influence of the inspired oxygen fraction on these indices before, during and after general anaesthesia. ⋯ The so-called non-invasive indices of pulmonary gas exchange do not correlate well with the calculated pulmonary shunt, which is regarded as the gold standard that reflects the various components of gas exchange. We speculate that the poor performance of these indices can be explained by the fact that they do not take into account the mixed venous saturation and, except for the alveolar to arterial oxygen tension ratio, ignore the effects of alveolar ventilation. The effect of the inspired oxygen fraction on these ratios makes them difficult to interpret if similar inspired oxygen fractions are not used. The effect of the FiO2 on these indices could possibly be explained by the denitrogenation and collapse of alveoli with low ventilation perfusion ratios. The change in the slope of the FiO2 and the indices that was demonstrated during anaesthesia could possibly be explained by the expected change in the mixed venous saturation that occurs during anaesthesia.
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Comparative Study
The changing pattern of penetrating torso trauma in KwaZulu/Natal--a clinical and pathological review.
The number of patients who sustained penetrating torso trauma and were admitted to King Edward VIII Hospital and the surgical intensive care unit were reviewed over 10- and 5-year periods respectively. For the last 4 months of 1992, a comparison was made between victims of trauma admitted to hospital and those whose bodies were taken directly to the South African Police medicolegal laboratories in Gale Street, Durban, where the majority of medicolegal autopsies in the Durban metropolitan area are performed. The total number of hospital admissions has not changed during the last decade, but the aetiology of injury has altered considerably. ⋯ Direct admission to the mortuary was three times as common in cases of gunshot compared with stab wounds. The hospital mortality rate for gunshot wounds was 8 times that for stab wounds. The establishment of dedicated trauma centres is essential for the treatment of these injuries, and strategies to control the use of firearms are vital.
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To determine characteristics of older infants and children admitted to the paediatric intensive care unit (PICU) at Johannesburg Hospital; and to evaluate an admission score based on the PRISM score (an index of severity of illness) as a possible means for selection of patients for admission to the PICU. ⋯ PICU facilities at Johannesburg Hospital are insufficient to meet the demand. An admission score based on the PRISM score could assist in the selection of patients for these limited PICU facilities.