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Biomedical subjects

K Sankaran

Publications and source records attributed to K Sankaran.

At least 91 records · Page 5Linked to original sources
PubMed1982

Use of metoclopramide in preterm infants.

6 preterm infants with birth weights ranging from 790 to 1,040 g and gestational ages of 26-35 weeks were given metoclopramide at a mean postnatal age of 35 days. The infants were selected only after fulfilling rigid clinical criteria. All infants were spontaneously breathing and were on parenteral nutrition with 3% Vamin and 10% Neutralipid. Metoclopramide, 0.1 mg/kg/day, was given intravenously in three divided doses. Progress was monitored using abdominal girth, gastric residual aspirate before each feed, intestinal transit times, daily weight gain, number of episodes of vomiting or regurgitation and assessment of tolerance to increasing amounts of feeds. Excellent response was seen in all infants. Withdrawal of the drug led to prompt recurrence of all symptoms and signs which again disappeared on reinstitution of the medication. No untoward side-effects were noted during the administration of the drug. We conclude that, in selected cases, metoclopramide may be used for persistent functional feeding intolerance and gastric stasis.

Gastric Emptying↗
PubMed1981

Systolic time intervals in chronic severe anaemia and effect of diuretic and digitalis.

Systolic time intervals were measured from simultaneous high speed recordings of the electrocardiogram, phonocardiogram, and carotid artery pulse in 15 men with chronic severe anaemia not in heart failure and with a normal heart size, and in 15 normal men. Heart rates, electromechanical systole (QS2), pre-ejection period index (PEPI), left ventricular ejection time index (LVETI), and the ratio of pre-ejection period to left ventricular ejection time (PEP/LVET) did not differ significantly in the two groups. After the intravenous administration of frusemide in 10 of the anaemic patients, the pre-ejection period index was prolonged, the PEP/LVET ratio increased, heart rate increased, and the left ventricular ejection time index shortened. Intravenous digoxin did not alter the QS2 interval and heart rate significantly in the anaemic subjects. Left ventricular function in chronic severe anaemia as measured by systolic time intervals does not differ from that of normal controls. The effect of frusemide on the systolic time intervals is explained as an effect of the fall in preload, bringing cardiac function further down on the ascending limb of the Frank-Starling curve. Other related studies are discussed.

Adult↗
PubMed1981

Effect of lung inflation on ventilation and various phases of the respiratory cycle in preterm infants.

The effect of sudden and sustained lung inflation on inspiratory time (Ti), expiratory time (Te) and duration of apnea, as a translation of the Hering-Breuer reflex, has not been systematically analyzed in preterm infants. To examine such effects, 10 infants (body weight 1,550 +/- 110 g; gestational age 31 +/- 1 weeks) were studied. Lung inflation was obtained by applying negative pressure around the chest using a negative pressure incubator. After a control period, lung volume functional residual capacity was increased by an average of 14, 23, 34 and 53%. During lung inflation, Ti, Te, total respiratory cycle duration, incidence and duration of apnea increased. Minute ventilation decreased due to a decrease in frequency. Tidal volume decreased but not significantly. Inspiratory and expiratory flows decreased. These results (1) confirm the presence of the Hering-Breuer reflex in preterm infants, as reflected by increased Te and appearance of apnea during lung inflation; and (2) show that contrary to expectations, Ti increased significantly with lung inflation.

Apnea↗
PubMed1981

Estimated cerebral blood flow in term infants with hypoxic-ischemic encephalopathy.

Estimated cerebral blood flow (eCBF) was measured sequentially in seven term infants with evidence of hypoxic-ischemic encephalopathy (HIE) and compared with that of normal-term infants. The eCBF was determined by a noninvasive method involving brief bilateral jugular venous occlusion with simultaneous measurement of occipitofrontal circumference. There was a significant decrease in eCBF on day 2 (30 +/- 4 ml/min/100 g brain weight) and on day 4 (36 +/- 5 ml/min/100 g brain weight) compared with control values (56 +/- 4 ml/min/100 g brain weight; 54 +/- 4 ml/min/100 g brain weight) (P less than 0.01). The alveolar CO2 was significantly lower on days 2 and 4 in the HIE group (P less than 0.001), and these values increased to control values by day 6. There was no significant correlation between estimated cerebral blood flow and alveolar CO2 in infants with HIE. We conclude that term infants with evidence of hypoxic-ischemic encephalopathy demonstrate lowered eCBF in the first 4 days of life.

Asphyxia Neonatorum↗
PubMed1980

Effect of inhaling 100% O2 on ventilation and acid-base balance in cerebrospinal fluid of neonates.

If 100% O2 produces hyperventilation by increasing central CO2 due to cerebral vasoconstriction or dimished reduction of oxyhemoglobin, then, there should be a parallel decrease in alveolar and CSF PCO2 during O2 breathing in neonates. To test this hypothesis, we measured ventilation, alveolar PCO2 and CSF PCO2, pH and HCO2 before and 10-20 min after infants began breathing 100% O2. With 100% O2, minute ventilation increased from 0.193 +/- (SE) 0.013 (n = 7) to 0.252 +/- 0.013 liter/min/kg (p less than 0.015), PACO2 decreased from 42 +/- 2 to 38 +/- 2 mm Hg (p less than 0.005), CSF PCO2 decreased from 51 +/- 1 to 44 +/- 1 mm Hg (p less than 0.015), and pH increased from 7.308 +/- 0.013 to 7.354 +/- 0.013 (p less than 0.05). CSF bicarbonate decreased, but not significantly. These findings, showing a trend toward alkalosis, suggest that the neonate, like the adult man, induces hyperventilation during hyperoxia via an increase in PCO2 at the central level.

Acid-Base Equilibrium↗
PubMed1979

Immediate and late ventillatory response to high and low O2 in preterm infants and adult subjects.

The differences in the immediate (30 sec or 1 min) and late (5 min) ventilatory response to high and low O2 have not been quantitated in preterm infants and adult subjects using the same methods. It was thought that these differences might explain the paradoxical ventilatory response to CO2 at various O2 concentrations in preterm infants (12). Thus, 9 preterm infants and 10 adult subjects were given 21% O2 to breathe and then 100 or 15% O2 for 5 min each. Adults also breathed 15% O2 before 100% O2 or 12% O2 in order to make their resting arterial PO2 more comparable to those of infants breathing 21% O2. The ventilatory response to 100% O2 was the same in preterm infants and adult subjects, but the late response to 15% O2 remained paradoxical, ventilation decreasing at 5 min by 18% in infants and increasing by 19% in adults. The authors conclude: 1) the traditional concept of the ventilatory response to 100% O2 being different in infants and adult subjects is false; 2) the notion that the response to low O2 is paradoxical in infants is correct; and 3) the data do not explain why the response to CO2 under various background concentrations of O2 in infants is the reverse of that in adult subjects, but the depressed ventilatory response to hypoxia in infants may justify, at least in part, their flatter response to CO2 during low O2 breathing.

Adult↗
PubMed1979

Effect of sleep state on chest distortion and on the ventilatory response to CO2 in neonates.

In 10 preterm and 10 term infants, the effect of sleep state on chest distortion and on the ventilatory response to CO2 was assessed. It was found that chest distortion and ventilatory response to CO2 were independent of sleep state. Chest distortion, however, was more frequent in preterm than in term infants. The authors suggest that the increased prevalence of chest distortion in preterm infants is related to their highly compliant chest wall rather than to differences in sleep state.

Carbon Dioxide↗
PubMed1979

Quantitative noninvasive method to measure cerebral blood flow in newborn infants.

We measured cerebral blood flow (CBF) in 32 healthy neonates by venous occlusion plethysmography. Mean CBF was 63 ml/min/100 gm which compared favorably with invasive methods used in older children and adult subjects. We suggest that this is a useful method to quantify CBF in neonates. It may be valuable in assessing sequential changes occurring during asphyxia, intracranial hemorrhage, or during administration of various gas mixtures and drugs such as theophylline.

Blood Flow Velocity↗
PubMed1978

Physiologic changes induced by theophylline in the treatment of apnea in preterm infants.

Ten preterm infants (birth weight 0.970 to 2.495 kg) with apnea due to periodic breathing (apneic interval = 5 to 10 seconds) or with "serious apnea" (greater than or equal to 20 seconds) were studied before and after the administration of theophylline. We determined the incidence of apnea, respiratory minute volume, alveolar gases, arterial gases and pH, "specific" compliance, functional residual capacity, and work of breathing. Theophylline decreased the incidence of apnea (P less than .05), increased respiratory minute volume (P less than 0.001), decreased (PACO2 (and PaCO2 P less than 0.001), increased the slope of the CO2 response curve (P less than 0.02) with a significant shift to the left (P less than 0.02). These findings suggest that the decreased incidence of apnea after theophylline is associated with an increase in alveolar ventilation and increased sensitivity to CO2 with a pronounced shift of the CO2 response curve to the left. These data are consistent with the idea that apnea is a reflection of a depressed respiratory system.

Apnea↗