Bruce G. MacMillan

Clinical characteristics of hypertension in burned children.

: Although systemic arterial hypertension has been recognized as a common complication of thermal injury in children, its clinical characteristics have not been defined. This review of 987 burned children, treated over an 11-year period, documents development of hypertension in 195 patients (19.8%). The problem occurs most frequently in males and in the 7--10-year age group, but does not correlate with racial origin. Incidence increases with burn severity up to a 40% total surface burn. The incidence did not vary with the year of treatment when changes in patient population were eliminated. Fifteen of the 195 patients had hypertensive encephalopathy and seizure problems. No other complication or change in mortality could be related to hypertension. The problem could not be related to location of the burn wound, drug treatment, or differences in transfusion and fluid therapy. Comparison of the highest daily blood pressure measurements between matched hypertensive and normotensive groups demonstrated that the hypertensive and normotensive groups demonstrated that the hypertension is limited to the acute phase of burn wound treatment and that blood pressures are normal after complete autografting. The encephalopathy and seizure problems indicate the need for careful blood pressure monitoring and effective antihypertensive therapy in the treatment of burned children.

The relationship between host defence variables and infection in severe thermal injury

Abstract Thirty-two patients with burns of 45 per cent or more were studied prospectively with serial (twice weekly) measurements of variables of host resistance against bacterial infection (neutrophil function, opsonization, C 8 , factor B, properdin and IgG). Thirty-seven episodes of bacteraemia occurred in 23 patients. Analysis of the immunological profiles immediately preceding and following each of the 37 bacteraemic episodes revealed predisposing abnormalities in 33. Of the 4 remaining bacteraemic episodes, studies were incomplete in 3. Neutrophil function was abnormal (neutrophil bactericidal index 4-0 or more) preceding 20 instances, normal or mildly abnormal in 8 and not done in 9. Abnormalities of opsonization preceded 18 of the 37 episodes. Circulating levels of C 3 increased in the serum of patients associated with 23 episodes of bacteraemia and fell during 12 episodes. In all but one of the 12 episodes where C 3 fell, there was an associated decrease in the opsonic index, but the opsonic index fell in 9 other patients without concomitant reduction in C 3 . Factor B rose during 18 episodes of bacteraemia, fell during 16, remained unchanged in 1 and could not be done in 2 because the patients died. However, factor B levels were always higher than normal. Properdin levels increased during 18 episodes, fell during 14 and remained unchanged in 1 (not available for 4 episodes). Strong evidence for consumption of opsonic proteins [a drop of 50 per cent or more in opsonic index associated with a fall in C 3 (B)] occurred in 5 episodes with suggestive evidence (drop of 25–49 per cent) in 2 others. In only 2 instances did factor B and properdin seem to be involved in a consumptive process. These data provide evidence that defects in both neutrophil bactericidal activity and opsonization predispose to bacterial infections in seriously burned patients.

A pathophysiologic study of the hypertension associated with burn injury in children.

Measurements of cardiac output, blood volume, plasma renin activity (PRA), serum aldosterone, plasma and urinary catecholamine levels, serum and urinary electrolyte levels, and of transfusion and fluid therapy have been made in eight hypertensive and seven normotensivc burned children. Studies were conducted during the acute phase of burn injury when hypertension was first diagnosed and were repeated just before discharge from the hospital. Hypertensive patients perfused at an inappropriately high total peripheral resistance and hypervolemia, was demonstrated in the hypertensive patients. No differences could be demonstrated between hypertensive or normotensive patients in PRA, aldosterone, catecholamine, or electrolyte levels. These data indicate that both the hypervolemia and the vasoconstrictor activity of PRA and/or catecholamines are present when hypertension develops in these patients. These data also suggest that the renin-angiotensin-aldosterone system is directly stimulated as part of the neuroendocrine response to trauma.

Technical Advances in Patient Isolation

Extension of gnotobiotic techniques from the animal laboratory to the clinical ward presents a number of problems and challenges. Previous publication by Levenson and Trexler, as well as Haynes and others, have reported some of the uses and advantages of reverse isolation technique with patient isolators both in the operating room and on the surgical ward. The use of these techniques in the clinical management of patients and in the clinical research of infection and immunologic response to infection has also been demonstrated. Much work has been done which indicates that clinical gnotobiotic research and application to patient care will develop rapidly and expand to new areas as the technical problem of patient care in an isolator are minimized.