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Cooling and oedema formation
Abstracts
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post bum there was vascular filling to 85 per cent of the thickness of the dermis in all animals. Bv 8 h dermal perfusion had fallen to 40 per cent of dkrmal thickness and at 24 h no dermal perfusion occurred. At 24 h only the subdermal vessels contained indian ink. The animals wounds which were allowed to heal showed no regeneration of dermal appendages grossly or microscopically. In these burned animals heparin failed to prevent progressive dermal ischaemia or to allow regeneration of dermal appendages. Robson M. C., Kucan J. O., Paik K.-I. et al. (1979) The effect of heparin on dermal ischaemia after burning. Burns 5,260. Studies of complement
consumption
The ability of tissues changed by heat to activate the complement system has been studied in rats. The results showed that heat-precipitated plasma proteins can activate the complement system as can pieces of tissue damaged by heat in situ and then excised from the animals’ hind legs. Normal hind leg tissue cannot activate the complement system. Studies with chelating agents showed that the alternative pathway of complement activation was stimulated by both the heat denatured tissue and plasma proteins. Heideman M. and Gelin L.-E. (1979) Imoaired host defence for infections due to‘ complement consumption by tissues changed by heat. Burns 5,245. Cooling and oedema formation Cooling the burned area has been reported to decrease wound oedema and pain and is useful as a first aid measure. However, since cold also decreases peripheral blood flow it could also be harmful to a deep bum. Studies were therefore carried out to measure the effect of cooling applied immediately and 2 min after burning (85 OC for 10 s) on oedema formation and resorption in a deep partial-thickness skin loss bum of the hind limbs of sheep. The volume of oedema was estimated using dichromatic absorptiometry. Immediate application of cold by immersion in saline at 15 ‘C for 30 min reduced the oedema of the burn and did not impair resorption rate compared with control limbs, the fluid content returning to normal within 7 days. Cold treatment beginning 2 min after the bum did not decrease oedema formation and did impair resorption. Fifteen per cent of the oedema fluid was still present after 7 days, suggesting that further injury to the vasculature of the bum wound occurred when cooling was delayed until 2 min after burning. Demling R. H., Mazess R. B. and Wolberg W. (1979) The effect of immediate and delayed cold immersion on bum oedema formation and resorption. J. Truuma 19,56. Heparin and oedema formation Heparin has been reported to decrease wound oedema as well as improve the clearance of excess fluid after
bums. As no quantitative data on bum oedema are available to support these statements studies were carried out on the effect of therapeutic doses of heparin on oedema formation and resorption in the sheep hind limb after deep partial- (85 “C) or fullthickness 95 ‘C) skin loss bums. Heparin was given as a continuous infusion for 24 hours to increase clotting time 2.5 times. The volume of oedema was measured using dichromatic absorptiometry. The results indicated that heparin did not decrease the quantity of oedema produced after a deep partial-thickness skin loss bum or increase the rate of resorption of fluid. In the full-thickness skin loss bums the treatment with heparin results in a significant increase in tissue oedema (P < 0.005). Clearance of oedema was markedly decreased after the full-thickness skin loss bum as compared with partial-thickness bums. Heparin did not improve the process of resorption. Demling R. H., Mazess R., Hanson J. et al. (1979) Effect of heparin on oedema after second and third degree bums. J. Surg. Rex 26,27. Pulmonary
microcirculation
Direct observation, intermittent photographs and tine records ofthe pulmonary microcirculation in rats were made before, immediately after and from 24 to 72 h after a full-thickness skin loss bum covering 40 per cent of the body surface. A combination of quartz rod transillumination and dark field illumination was used. In unburned animals rapid and continuous blood flow occurred in arterioles, venules and capillaries with no relationship to the phase of the cardiac cycle. Between IO and 60 min post bum there was a severe reduction in capillaries associated with microaggregates and in spite of constriction of most arterioles and venules there was a continuing rapid blood flow in these latter vessels. From 24 to 72 h post bum microaggregates were found in some capillaries with resultant stopped flow, many large shunts from arterioles to venules were observed and rapid and continuous blood flow occurred in slightly dilated arterioles, venules and many capillaries. Histological examination of lung tissue 72 h post bum showed evidence of interstitial oedema and aggregates of red cells. These observations indicated an increased pulmonary vascular resistance following severe bums apparently due to aggregation of various cells, mainly red cells. The increased resistance may be responsible for the opening of shunts and consequent progressive pulmonary insufficiency. Hayashi M., Bond T. P., Guest M. M. et al. (1979) Pulmonary microcirculation following full-thickness bums. Burns 5,227. LABORATORY
STUDIES
Oxidase activity in leucocytes As a defect in intracellular bactericidal capacity in leucocytes from severely burned patients appears to correspond with increases in bacterial woundxolonization and ultimately sepsis, and as this defect is
65
post bum there was vascular filling to 85 per cent of the thickness of the dermis in all animals. Bv 8 h dermal perfusion had fallen to 40 per cent of dkrmal thickness and at 24 h no dermal perfusion occurred. At 24 h only the subdermal vessels contained indian ink. The animals wounds which were allowed to heal showed no regeneration of dermal appendages grossly or microscopically. In these burned animals heparin failed to prevent progressive dermal ischaemia or to allow regeneration of dermal appendages. Robson M. C., Kucan J. O., Paik K.-I. et al. (1979) The effect of heparin on dermal ischaemia after burning. Burns 5,260. Studies of complement
consumption
The ability of tissues changed by heat to activate the complement system has been studied in rats. The results showed that heat-precipitated plasma proteins can activate the complement system as can pieces of tissue damaged by heat in situ and then excised from the animals’ hind legs. Normal hind leg tissue cannot activate the complement system. Studies with chelating agents showed that the alternative pathway of complement activation was stimulated by both the heat denatured tissue and plasma proteins. Heideman M. and Gelin L.-E. (1979) Imoaired host defence for infections due to‘ complement consumption by tissues changed by heat. Burns 5,245. Cooling and oedema formation Cooling the burned area has been reported to decrease wound oedema and pain and is useful as a first aid measure. However, since cold also decreases peripheral blood flow it could also be harmful to a deep bum. Studies were therefore carried out to measure the effect of cooling applied immediately and 2 min after burning (85 OC for 10 s) on oedema formation and resorption in a deep partial-thickness skin loss bum of the hind limbs of sheep. The volume of oedema was estimated using dichromatic absorptiometry. Immediate application of cold by immersion in saline at 15 ‘C for 30 min reduced the oedema of the burn and did not impair resorption rate compared with control limbs, the fluid content returning to normal within 7 days. Cold treatment beginning 2 min after the bum did not decrease oedema formation and did impair resorption. Fifteen per cent of the oedema fluid was still present after 7 days, suggesting that further injury to the vasculature of the bum wound occurred when cooling was delayed until 2 min after burning. Demling R. H., Mazess R. B. and Wolberg W. (1979) The effect of immediate and delayed cold immersion on bum oedema formation and resorption. J. Truuma 19,56. Heparin and oedema formation Heparin has been reported to decrease wound oedema as well as improve the clearance of excess fluid after
bums. As no quantitative data on bum oedema are available to support these statements studies were carried out on the effect of therapeutic doses of heparin on oedema formation and resorption in the sheep hind limb after deep partial- (85 “C) or fullthickness 95 ‘C) skin loss bums. Heparin was given as a continuous infusion for 24 hours to increase clotting time 2.5 times. The volume of oedema was measured using dichromatic absorptiometry. The results indicated that heparin did not decrease the quantity of oedema produced after a deep partial-thickness skin loss bum or increase the rate of resorption of fluid. In the full-thickness skin loss bums the treatment with heparin results in a significant increase in tissue oedema (P < 0.005). Clearance of oedema was markedly decreased after the full-thickness skin loss bum as compared with partial-thickness bums. Heparin did not improve the process of resorption. Demling R. H., Mazess R., Hanson J. et al. (1979) Effect of heparin on oedema after second and third degree bums. J. Surg. Rex 26,27. Pulmonary
microcirculation
Direct observation, intermittent photographs and tine records ofthe pulmonary microcirculation in rats were made before, immediately after and from 24 to 72 h after a full-thickness skin loss bum covering 40 per cent of the body surface. A combination of quartz rod transillumination and dark field illumination was used. In unburned animals rapid and continuous blood flow occurred in arterioles, venules and capillaries with no relationship to the phase of the cardiac cycle. Between IO and 60 min post bum there was a severe reduction in capillaries associated with microaggregates and in spite of constriction of most arterioles and venules there was a continuing rapid blood flow in these latter vessels. From 24 to 72 h post bum microaggregates were found in some capillaries with resultant stopped flow, many large shunts from arterioles to venules were observed and rapid and continuous blood flow occurred in slightly dilated arterioles, venules and many capillaries. Histological examination of lung tissue 72 h post bum showed evidence of interstitial oedema and aggregates of red cells. These observations indicated an increased pulmonary vascular resistance following severe bums apparently due to aggregation of various cells, mainly red cells. The increased resistance may be responsible for the opening of shunts and consequent progressive pulmonary insufficiency. Hayashi M., Bond T. P., Guest M. M. et al. (1979) Pulmonary microcirculation following full-thickness bums. Burns 5,227. LABORATORY
STUDIES
Oxidase activity in leucocytes As a defect in intracellular bactericidal capacity in leucocytes from severely burned patients appears to correspond with increases in bacterial woundxolonization and ultimately sepsis, and as this defect is