Biology of the neonate
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Biology of the neonate · Jan 1995
Case ReportsIntrathecal immune response in neonatal Flavobacterium meningosepticum meningitis.
Neonates are predisposed to serious infections such as meningitis, probably due to their immature host reaction to the pathogens. We have studied the intrathecal immune response in 2 newborns with Flavobacterium meningosepticum meningitis. ⋯ In addition, an intrathecal increase and subsequent decrease of both C3dg and TCC (terminal complement complex) were observed in 1 patient. We conclude that immunoglobulin production and complement activation may occur in neonatal CSF.
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Over the last 26 years diaphragm pacing has been used in over 400 adults and 70 children to support ventilation and oxygenation. Diaphragm pacing can be useful for conditions in which the brain stem respiratory centers provide little or no stimulation to the respiratory muscles, i.e. central hypoventilation syndrome, Arnold-Chiari malformation/brain stem dysfunction, and high quadriplegia. Because the pacing systems are so portable, the greatest advantages accrue to those patients who require ventilatory support both while awake and asleep. ⋯ Mean time to failure was 56 months. Of our 36 patients who had diaphragm pacing systems implanted, 26 are alive and 22 are currently using the pacing systems. wo recent advances may further improve the long-term outcome of patients using diaphragm pacing. Smaller, better encapsulated receivers may improve system longevity and a new stimulus electrode may reduce the risk of diaphragmatic damage.
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Biology of the neonate · Jan 1994
Cerebral blood flow autoregulation after moderate hypoxemia in the newborn piglet.
The isotope-labelled microsphere method was used to study blood flow autoregulation in the brainstem (BS), cerebellum (CBL), cerebrum (CBR) and choroid plexus (ChPl) in 21 newborn piglets exposed to hypoxemia and/or hypovolemia. One group of piglets (n = 7) was made hypoxemic by breathing 10% O2 for 10 min, a second group (n = 8) was studied during hypoxemia (10% O2, 10 min), followed by hypovolemia (bleeding 20% of estimated blood volume). A third group of piglets (n = 6) was made hypovolemic by bleeding 20%. ⋯ However, animals exposed to both hypoxemia and hypovolemia were still hypotensive 60 min after the hypoxemic insult. Cardiac output (CO) was not affected by hypoxemia, but was consistently reduced in hypovolemia. We therefore speculate that in the newborn a reduced CO might be a more specific parameter for hypovolemia than a low blood pressure.
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In premature neonates (25-34 weeks gestation) who were given morphine intravenously during the first 24 h of life, only morphine, and morphine-3-glucuronide (M3G) were detected in plasma obtained after a 2-hour loading infusion, but morphine-6-glucuronide (M6G) could also be quantified following 24 h of continuous infusion. M3G/morphine and M6G/morphine plasma concentration ratios increased significantly with increasing birth weight. However, the M6G/M3G plasma concentration ratio decreased with increasing birth weight (and gestational age), thus providing the first indication in vivo of the differential development of uridinediphosphate glucuronosyltransferases in humans.
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Biology of the neonate · Jan 1994
Comparative StudyValidation of cardiac output measurements with noninvasive Doppler echocardiography by thermodilution and Fick methods in newborn piglets.
Since cardiac output measured by the noninvasive pulsed Doppler technique has not been well correlated to results from the invasive thermodilution or Fick methods in neonates, the three methods were evaluated in 6 sedated newborn piglets (age < or = 7 days, weight 1.5 +/- 0.7 kg) in room air and after 10 min of hypoxia. Doppler velocities were measured in the ascending aorta, and the aortic root diameter was measured in early diastole. A Swan-Ganz catheter in the left pulmonary artery sampled mixed venous blood for central venous O2 content and measured cardiac output by thermodilution. ⋯ Fick methods, r = 0.92; thermodilution vs. Fick method, r = 0.95). The mean +/- SD of the percent difference between values obtained by Doppler echocardiography and thermodilution was 4.2 +/- 14.4% in room air and 12.8 +/- 14.4% in hypoxia, whereas differences in values obtained by Doppler and Fick methods was 6 +/- 14.9% in room air and 14.7 +/- 8.5% with hypoxia.(ABSTRACT TRUNCATED AT 250 WORDS)