Effects of asphyxia on lung fluid balance in baby lambs.

Hansen, Thomas N.; Hazinski, Thomas A.; Bland, Richard D.

doi:10.1172/jci111432

Cited by 15 publications

(7 citation statements)

References 32 publications

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“…In Fisher's study there was no effect of acidosis on cardiac output at an arterial pH > 7.30 (Fisher DJ, personal communication) and in our previous study in older lambs, cardiac output increased at all rates of dopamine infusion despite a similar mild mixed acidosis (2). Finally, in previous studies where mild metabolic acidosis was induced by prolonged hypoxia (24), mixed acidosis was induced by hypoxia plus C 0 2 rebreathing (25), or pure respiratory acidosis was induced by C 0 2 rebreathing (26) cardiac output always increased.…”

Section: Effects Of Dopumine Infusionmentioning

confidence: 84%

The Effects of Dopamine Infusion on Regional Blood Flow in Newborn Lambs

et al. 1987

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ABSTRACT. The purpose of this project was to investigate the effects of high rates of dopamine infusion on cardiac output and regional blood flow in the lamb. We studied eight unanesthetized newborn lambs (mean age 7 + 2 days) during a 15-min baseline period and while infusing dopamine at 5-, 20-, 80-, and 160 pg/kg/min. We measured cardiac output and mean aortic, pulmonary arterial and left atrial pressures, and organ blood flow using radionuclidelabeled microspheres at each rate of dopamine infusion. Cardiac output increased significantly with increasing rates of infusion up to 80 pg/kg/min but decreased at 160 pg/kg/ min. Aortic, pulmonary arterial, and left atrial pressures increased at rates of infusion above 5 pg/kg/min. Blood flow to all organs was unchanged at the 5 pg/kg/min rate of infusion of dopamine while blood flow to the brain and heart increased at the 80 pg/kg/min rate of infusion and blood flow to the gut and kidney decreased. We conclude that dopamine is an effective inotropic agent in the newborn lamb but that an inotropic:afterload mismatch exists at high infusion rates. Despite an increase in cardiac output at low rates of infusion, dopamine did not selectively vasodilate the vascular bed of any organs tested. Furthermore, at high rates of infusion dopamine actually impaired blood flow to the gut and kidney. (Pediatr Res 21: 131-136, 1987) Dopamine remains an extensively used catecholamine in the management of shock in critically ill infants and children (1). We recently studied the effects of dopamine on hemodynamics in 2-to 3-wk-old lambs and found it to be an effective inotropic agent (2). However, inherent properties of neonatal myocardium may render it relatively unresponsive to the inotropic actions of dopamine and the same effects may not occur in the younger lamb. In the clinical setting, myocardial immaturity may prompt the use of rates of infusion of dopamine in excess of those currently recommended (1). The effects of high rates of infusion on regional blood flow in the newborn are unknown.The purpose of our study was to investigate the effects of dopamine on regional blood flow in newborn lambs over a wide range of infusion rates. We hypothesized that in the newborn lamb dopamine would not increase cardiac output at conventionally used rates of infusion but might at higher rates. At these higher rates, however, we anticipated that the a-adrenergic effect of dopamine would compromise blood flow to vital organs. MATERIALS AND METHODSSurgical preparations. We operated on eight lambs using halothane and nitrous oxide anesthesia delivered by a piston type ventilator. From a left hindlimb cutdown we inserted polyvinyl catheters into a peripheral artery and vein and advanced them into the descending aorta and inferior vena cava, respectively. We also inserted a 3.5 Fr thermistor wire (Edwards Laboratories, Inc., Irvine, CA) into a peripheral artery by separate hindlimb cutdown and advanced it into the descending aorta. Finally, we placed a polyvinyl catheter in a forelimb artery and ad...

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Section: Effects Of Dopumine Infusionmentioning

confidence: 84%

The Effects of Dopamine Infusion on Regional Blood Flow in Newborn Lambs

et al. 1987

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“…Bland et al (5) and Landolt et al (6) failed to detect increases in lung lymph flow in adult sheep during hypoxia, even with the added stress of increased blood flow. In contrast, other studies have demonstrated increases in lymph flow in newborn lambs (7) and dogs (8-10) after hypoxia. Furthermore, studies in isolated perfused dog lungs have revealed increased filtration and reflection coefficients consistent with increased vascular permeability after brief exposures to anoxic gas (1 1, 12).…”

mentioning

confidence: 74%

“…Considerable evidence exists that suggests that the pulmonary vascular response to hypoxia in sheep may differ from those of other mammalian species (2,8,33,34). Specifically, histologic evidence of interstitial edema is lacking in the ovine species after hypoxia, and a report in newborn lambs actually showed hypoxia-induced decreases in extravascular lung water (7). In contrast, other species including the rat demonstrate endothelial injury and edema formation similar to findings reported in human cases of high altitude pulmonary edema (2,3,15,16,17,30).…”

Section: Methodsmentioning

confidence: 94%

Hypoxia-induced increases in pulmonary transvascular protein escape in rats. Modulation by glucocorticoids.

Stelzner¹,

O'Brien²,

Sato³

et al. 1988

J. Clin. Invest.

111

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Pulmonary edema after ascent to altitude is well recognized but its pathogenesis is poorly understood. To determine whether altitude exposure increases lung vascular permeability, we exposed rats to a simulated altitude of -14,500 feet (barometric pressure [Pbi 450 Torr) and measured the pulmonary transvascular escape of radiolabeled '25l-albumin corrected for lung blood content with 51Cr-tagged red blood cells (protein leak index = PLI). Exposures of 24 and 48 h caused significant increases in PLI (2.30±0.08 and 2.40±0.06) compared with normoxic controls (1.76±0.06), but brief hypoxic exposures of 1-13 h produced no increase in PLI, despite comparable increases in pulmonary artery pressure. There were associated increases in gravimetric estimates of lung water in the altitude-exposed groups and perivascular edema cuffs on histologic examination. Normobaric hypoxia (48 h; fractional inspired oxygen concentration [FI021 = 15%) also increased lung transvascular protein escape and lung water.Dexamethasone has been used to prevent and treat altitude-induced illnesses, but its mechanism of action is unclear. Dexamethasone (0.5 or 0.05 mg/kg per 12 h) started 12 h before and continued during 48 h of altitude exposure prevented the hypoxia-induced increases in transvascular protein escape and lung water. Hemodynamic measurements (mean pulmonary artery pressure and cardiac output) were unaffected by dexamethasone, suggesting that its effect was not due to a reduction in pulmonary artery pressure or flow. The role of endogenous glucocorticoid activity was assessed in adrenalectomized rats that showed augmented hypoxia-induced increases in transvascular protein escape, which were prevented by exogenous glucocorticoid replacement. In summary, subacute hypoxic exposures increased pulmonary transvascular protein escape and lung water in rats. Dexamethasone prevented these changes independent of reductions of mean pulmonary artery pressure or flow, whereas adrenalectomy increased pulmonary vascular permeability and edema at altitude. Increases in vascular permeability in hypoxia could contribute to the development of high-altitude pulmonary edema and endogenous glucocorticoids may have an important influence on pulmonary vascular permeability in hypoxia. Introduction Rapid ascent to high altitude may be associated with the development of pulmonary edema (HAPE)' (1,2 Despite this, attempts to demonstrate hypoxia-induced changes in permeability in the laboratory have produced conflicting results. Bland et al. (5) and Landolt et al. (6) failed to detect increases in lung lymph flow in adult sheep during hypoxia, even with the added stress of increased blood flow. In contrast, other studies have demonstrated increases in lymph flow in newborn lambs (7) and dogs (8-10) after hypoxia. Furthermore, studies in isolated perfused dog lungs have revealed increased filtration and reflection coefficients consistent with increased vascular permeability after brief exposures to anoxic gas (1 1, 12). Differences in both species and ...

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“…The pathophysiological mechanism may result from reactions of capillaries in the lungs which are similar to those in the peripheral vessels. A causal relationship is postulated between a sudden effect of cold and its consequences as disturbed circulation and hypoxia/acidosis [3,5,6].…”

Section: Discussionmentioning

confidence: 99%

Clinical and morphological aspects of death due to liquid nitrogen

Kernbach-Wighton

Kijewski

Schwanke³

et al. 1998

International Journal of Legal Medicine

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A 24-year-old student died while filling flasks with liquid nitrogen. The arms, legs and back were frozen and the face, ears and neck showed a dark red and livid colour with horizontal lines of demarcation. In the electrocardiogram, the heart showed asystolia followed by wide ventricular complexes. The patient was intubated orally as the situs of the larynx and pharynx showed no pathology findings. Cardiopulmonary resuscitation was carried out and terminated after 90 min. Unfortunately, the body temperature was not measured. The gas analysis of venous blood showed metabolic acidosis and oxygen deficiency. The student had worked alone with nitrogen, without opening the windows and without a working ventilation system. While filling the third flask he lost consciousness. As nitrogen does not cause characteristic prodromal signs he laid on the floor and was unable to help himself. The liquid nitrogen which was still escaping spread over the floor and vaporized. The student died from asphyxia due to oxygen deficiency in an atmosphere of nitrogen.

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Effects of asphyxia on lung fluid balance in baby lambs.

Cited by 15 publications

References 32 publications

The Effects of Dopamine Infusion on Regional Blood Flow in Newborn Lambs

The Effects of Dopamine Infusion on Regional Blood Flow in Newborn Lambs

Hypoxia-induced increases in pulmonary transvascular protein escape in rats. Modulation by glucocorticoids.

Clinical and morphological aspects of death due to liquid nitrogen

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