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Biomedical subjects

D G Batton

Publications and source records attributed to D G Batton.

25 records · Page 2Linked to original sources

Effect of pneumothorax-induced systemic blood pressure alterations on the cerebral circulation in newborn dogs.

Pneumothorax has been associated with intraventricular hemorrhage in premature infants, although the mechanism for this relationship is not clear. Because alterations in cerebral blood flow are believed to be important in the pathogenesis of intraventricular hemorrhage, the effect of induced pneumothorax and subsequent evacuation on the cerebral circulation in 16 newborn dogs was evaluated. Continuous Doppler ultrasound was used to monitor changes in cerebral blood velocity. Pneumothorax was induced by slow infusion (5 cc/kg/min) or rapid infusion (5 to 10 seconds) of air to reduce mean arterial blood pressure to half of base-line levels. Both methods of pneumothorax induction resulted in significant elevations of central venous pressure and intrapleural pressure, whereas mean arterial blood pressure and cerebral blood velocity decreased significantly. In each group, the pneumothorax was evacuated either by slow withdrawal of air (10 cc/kg/min) or as rapidly as possible. Rapid evacuation of air resulted in an immediate increase in mean arterial blood pressure and cerebral blood velocity to supranormal levels. Slow evacuation led to a more gradual normalization of mean arterial blood pressure and cerebral blood velocity. It is suggested that the precipitous increases in mean arterial blood pressure and cerebral blood velocity following rapid evacuation of a tension pneumothorax may account for the observed association between pneumothorax and intraventricular hemorrhage in premature infants.

Animals↗

Regional cerebral blood flow, cerebral blood velocity, and pulsatility index in newborn dogs.

A technique employing a Doppler ultrasound probe to measure cerebral blood velocity was used to study the cerebral circulation continuously in 30 newborn mongrel dogs. Utilizing a transfontanelle approach, the probe was maintained in fixed position throughout a given experiment. In 20 animals, changes in systolic, diastolic, and mean cerebral blood velocity during hypo- and hypercarbia were directly correlated (P less than 0.01) with changes in regional cerebral blood flow (rCBF) determined in 12 regions of the brain by the [14C]iodoantipyrine autoradiography technique. In an additional 10 dogs, multiple determinations of systolic, diastolic, and mean blood velocity were made over a wide range of PaCO2 values and found to be directly related to the PaCO2 (P less than 0.001). These data suggest that changes in cerebral blood velocity are closely related to changes in cerebral blood flow. We also calculated the pulsatility index (PI) from the peak systolic and end diastolic velocities and found a poor, but direct (r = 0.28, P less than 0.05) relationship between the PI and PaCO2 rather than the indirect relationship, which has been suggested in published clinical studies. We conclude that the Doppler technique may be valuable in monitoring dynamic events of the neonatal cerebral circulation if a constant probe position is maintained. Our results suggest, however, that the PI is not a reliable index of cerebral vascular resistance.

Animals↗

Use of peripheral intravenous cannulas in premature infants: a controlled study.

A randomized, controlled study was done to determine whether a 25-gauge steel needle or a 24-gauge Teflon catheter was preferable for the administration of peripheral intravenous fluids and medications to premature infants. A total of 58 cannulas--28 steel needles and 30 catheters--were used in 34 infants. The needles remained in place for 15.4 +/- 13.2 hours (mean +/- SD) and the Teflon catheters for 49.5 +/- 30.9 hours (mean +/- SD). All of the steel needles had to be removed because of infiltration whereas only 17/30 (57%) of the catheters infiltrated. A local inflammatory reaction, which was not related to infection, occurred with 11/30 (37%) of the Teflon catheters. Following removal, Staphylococcus epidermidis was grown from the culture of 1/19 steel needles and 1/25 catheters. In both instances this organism was thought to be a contaminant. Teflon catheters remain functional three times longer than steel needles with no apparent increase in complications. The use of these catheters, therefore, appears to be the preferred method for administering intravenous fluids to premature infants.

Catheterization↗

Serum potassium changes following packed red cell transfusions in newborn infants.

We studied the effect of packed red cell transfusions on serum potassium levels in sick newborn infants. In 11 transfusions the infants' serum potassium levels fell from a mean of 5.1 +/- 1.2 mEq per 1 (SD) to 4.9 +/- 1.2 mEq per 1 within 1 hour of the transfusion. Plasma potassium in stored packed red cells rose markedly within 48 hours of drawing. In spite of this, the transfusion of 10 ml per kg of packed red cells did not affect the serum potassium concentration in the newborn infant.

Blood Preservation↗

Fetal schistocytic hemolytic anemia and umbilical vein varix.

A rare case of schistocytic hemolytic anemia presenting in a fetus secondary to a varix of the intra-abdominal umbilical vein is reported. A patient was referred to our hospital at 32 weeks of gestation because of an abnormal hypoechoic finding in the fetal liver. Prenatal ultrasound showed turbulent flow through a 12-mm diameter dilatation of the fetal intra-abdominal umbilical vein consistent with a varix. Cardiomegaly also was noted. At birth, the 1098-g, growth-retarded, male neonate was in severe congestive heart failure secondary to anemia as the initial hemoglobin was 5 g/dL. Additional evaluation found the anemia to be secondary to schistocytic hemolysis. After the neonate received a transfusion of packed erythrocytes and supportive care, the anemia quickly resolved, and he was discharged to home doing well after a 6-week stay in the neonatal intensive care unit. Prompt recognition of the varix prenatally and thorough evaluation of the newborn postnatally led to appropriate diagnosis and treatment.

Adult↗