Memories of the 1953-54 Oxygen Trial and its aftermath. The failure of success

Discovering Pain in Newborn Infants

Randomised Trial of Fentanyl Anesthesia in Preterm Babies Undergoing Surgery: Effects on the Stress Response. By Anand KJ, Sippell WG, and Aynsley-Green A. Lancet 1987; 1:243-8. Reprinted with permission.In a randomised controlled trial, preterm babies undergoing ligation of a patent ductus arteriosus were given nitrous oxide and D-tubocurarine, with (n = 8) or without (n = 8) the addition of fentanyl (10 μg/kg intravenously) to the anesthetic regimen. Major hormonal responses to surgery, as indicated by changes in plasma adrenaline, noradrenaline, glucagon, aldosterone, corticosterone, 11-deoxycorticosterone, and 11-deoxycortisol levels, in the insulin/glucagon molar ratio, and in blood glucose, lactate, and pyruvate concentrations were significantly greater in the nonfentanyl than in the fentanyl group. The urinary 3-methylhistidine/creatinine ratios were significantly greater in the nonfentanyl group on the second and third postoperative days. Compared with the fentanyl group, the nonfentanyl group had circulatory and metabolic complications postoperatively. The findings indicate that preterm babies mount a substantial stress response to surgery under anesthesia with nitrous oxide and curare and that prevention of this response by fentanyl anesthesia may be associated with an improved postoperative outcome.

Descriptive studies: what they can and cannot do

Descriptive studies often represent the first scientific toe in the water in new areas of inquiry. A fundamental element of descriptive reporting is a clear, specific, and measurable definition of the disease or condition in question. Like newspapers, good descriptive reporting answers the five basic W questions: who, what, why, when, where. and a sixth: so what? Case reports, case-series reports, cross-sectional studies, and surveillance studies deal with individuals, whereas ecological correlational studies examine populations. The case report is the least-publishable unit in medical literature. Case-series reports aggregate individual cases in one publication. Clustering of unusual cases in a short period often heralds a new epidemic, as happened with AIDS. Cross-sectional (prevalence) studies describe the health of populations. Surveillance can be thought of as watchfulness over a community; feedback to those who need to know is an integral component of surveillance. Ecological correlational studies look for associations between exposures and outcomes in populations-eg, per capita cigarette sales and rates of coronary artery disease-rather than in individuals. Three important uses of descriptive studies include trend analysis, health-care planning, and hypothesis generation. A frequent error in reports of descriptive studies is overstepping the data: studies without a comparison group allow no inferences to be drawn about associations, causal or otherwise. Hypotheses about causation from descriptive studies are often tested in rigorous analytical studies.