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Biomedical subjects

J Hodgman

Publications and source records attributed to J Hodgman.

At least 19 recordsLinked to original sources
PubMed1989

Polysomnographic sleep and waking states are similar in subsequent siblings of SIDS and control infants during the first six months of life.

Twenty-five subsequent siblings of infants who died of Sudden Infant Death Syndrome (SIDS) underwent 12-h overnight polygraphic recordings during the first week of life and at 1, 2, 3, 4, and 6 months of age. The polygraphic tracings from these infants were compared with those from 25 infants without a family history of SIDS. One dozen sleep and waking parameters were examined including state transition probabilities, the ratio between quiet sleep (QS) and active sleep (AS), the incidence and duration of sustained states and the stability of an infant's sleep and waking during the first half year of life. Variability within and between infants was marked with a reduction of variability in measures of QS at 3 months and of AS at 4 months of age. The similarities between subsequent siblings of SIDS and control infants far outweighted the differences. However, subsequent siblings exhibited a tendency, once asleep, to remain asleep longer than controls. This finding was observed in a comparison of 20 infants in each group. When five infants were added to each group, infants in both groups tended to awaken equally from QS, but once in AS the subsequent siblings tended to proceed into QS instead of awaken as the controls did.

Arousal↗
PubMed1988

Sleep and waking states in infancy: normative studies.

Twelve-hour polygraphic recordings were obtained in 20 normal healthy term infants at 1 week of age, at monthly intervals up to 4 months, and at 6 months of age. Each minute of these recordings was coded into active sleep (AS), quiet sleep (QS), wakefulness (AW), or indeterminate (IN) based on polygraphic and behavioral variables. For each state, a dozen variables were computed with the help of a laboratory computer. Together these variables describe trends in the development of sleep and wakefulness in the laboratory: an increase in QS and a concomitant decrease in AS, an increase in sustained episodes of these states, and continuous sleep onset in AS throughout this time span. Considerable variability appears to characterize immature sleep patterns, but a reduction in variability was noted between 3 and 4 months of age. The number of sustained sleep-state episodes and the percentage of AS and IN proved to be stable characteristics of individual infants. The large variability among and within infants sheds doubt on the usefulness of polygraphic monitoring of sleep states for early detection of abnormalities.

Child Development↗
PubMed1987

Effects of metaproterenol on pulmonary mechanics, oxygenation, and ventilation in infants with chronic lung disease.

Changes in pulmonary resistance, dynamic compliance, tidal volume, and transcutaneous PO2 and PCO2 after nebulized administration of metaproterenol were evaluated in eight newborn infants (birth weight 650 to 1060 g, gestational age 25 to 28 weeks) with chronic lung disease receiving mechanical ventilation. The infants were monitored continuously before and for 15 minutes after nebulization of metaproterenol during 3 consecutive days at mean age 34 days. There were significant increases in compliance, tidal volume, and tcPO2, and significant decreases in pulmonary resistance and tcPCO2. These data show that bronchospasm contributes significantly to the high pulmonary resistance in preterm infants with chronic lung disease and that metaproterenol is beneficial in the therapy of infants with chronic lung disease requiring mechanical ventilation.

Blood Gas Monitoring, Transcutaneous↗
PubMed1985

Cardiovascular and catecholamine changes after administration of pancuronium in distressed neonates.

Heart rate, blood pressure, transcutaneous gases, and catecholamine changes following intravenous injection of pancuronium were evaluated in seven ill newborn infants (birth weight: 1,280 to 4,500 g; gestational age, 29 to 42 weeks). Each infant was monitored continuously for 30 minutes before and 50 minutes after infusion of the paralyzing agent. There were no significant changes in transcutaneous gases, whereas significant increases in heart rate; systolic, diastolic, and mean blood pressures; and blood norepinephrine and epinephrine levels were found. The increase in heart rate lasted for 30 minutes, and the increase in blood pressure persisted for 50 minutes after administration of the drug. Because of the potential relationship between increased blood pressure and intraventricular hemorrhage and myocardial dysfunction, heart rate and blood pressure must be monitored during infusion of pancuronium in distressed newborns. These data suggest that pancuronium stimulates sympathetic activity in distressed newborns.

Blood Pressure↗
PubMed1984

The impact of certificate of need on CT scanning in Massachusetts.

Evidence suggests that prolonging the period of new technology diffusion has the potential of considerable cost savings, although some very real, noneconomic patient costs may be incurred. Yet hospital administrators will continue to face increasing pressure to buy newer and more expensive technologies, even before their efficacy has been established.

Certificate of Need↗
PubMed1981

Periodicity of sleep states is altered in infants at risk for the sudden infant death syndrome.

The normal succession of sleep and waking states through a night is disturbed in infants at risk for the sudden infant death syndrome. Compared with normal infants, siblings of the sudden infant death syndrome victims have longer intervals between active sleep epochs at particular times during the night in the newborn period and a decreased tendency to enter short waking periods at 2 and 3 months of age. The latter finding is interpreted as an increased tendency to remain asleep, or a relative failure to arouse from sleep in infants at risk.

Age Factors↗
PubMed1981

Factors affecting heated transcutaneous PO2 and unheated transcutaneous PO2 in preterm infants.

The authors evaluated transcutaneous PCO2 (PtcCO2) and PO2 (PtcO2) electrodes in 25 infants. Their diagnosis were severe hyaline membrane disease (HMD) (18), aspiration syndrome (3), severe hydrops, (3) persistent fetal circulation (6), and the others, congenital pneumonia, congenital plural effusion, pulmonary hemorrhage. In most all, the cardiovascular system was compromised, i.e., PDA with congestive heart failure and shock. PtcO2 electrode was heated to 43.5 degrees C while PtcCO2 electrode was not heated. Simultaneous arterial blood pressure (ABP), pH, arterial blood gases were obtained with the transcutaneous gas measurements. The data were analyzed first dividing all the paired arterial and transcutaneous gas tensions into those with and without cardiovascular drugs (dopamine, isoproterenol), and second, the paired values were divided into those taken (a) during severe acidosis (pH less than 7.25), (b) hypotension (less than 2 SD) of normal, and (c) hypotension and acidosis. These data show: (1) the unheated PtcCO2 and heated PtcO2 accurately correlated with the simultaneous arterial measurements: (2) PtcCO2 reflects tissue PCO2; (3) drugs affect both the PtcCO2 and PtcO2; (4) elevated PtcCO2 dissociating from the simultaneous PaCO2 in neonates with cardiovascular compromise results from decreased tissue perfusion. These data suggest that transcutaneous gas sensors perform dual functions; first, as gas monitors in patients without cardiovascular alterations, and second, in patients with cardiovascular compromise, PtcCO2 reflected tissue perfusion and PtcCO2 monitored oxygen delivery to the tissues.

Blood Gas Analysis↗
PubMed1981

Fetal heart rates during maternal wakefulness and sleep.

This study was designed to provide normative data on fetal heart rate (FHR), FHR variability, accelerations, and decelerations during maternal sleep in the third trimester of pregnancy and to identify rhythmicity in FHR variability. Twenty-four polygraphic recordings were obtained in 16 pregnant women at 32 and 36 weeks' gestation. FHR parameters were not predictably influenced by maternal sleep states. Cyclic changes in FHR variability with median cycle length of 53 minutes were observed. Accelerations and decelerations occurred an average of 12.2 and 4 times per 100 minutes, respectively. Bradycardia and tachycardia persisting beyond 10 minutes were not seen. FHR variability ranged from marked to decreased within recordings of the same subject; this observation has implications for non-stress testing of the fetus.

Female↗
PubMed1979

Respiration during the first six months of life in normal infants: II. The emergence of a circadian pattern.

The objective of the present study was to investigate the emergence of circadian patterns in respiratory rates. Twenty-five neurologically normal infants were monitored for 12-hours during the first week of life and at one, two, three, four and six months of age. Each minute of the recordings of EEG, eye movements, somatic activity, respiration, ECG and temperature was coded into Active sleep (AS), Quiet sleep (QS), Indeterminate (IN) and Awake (AW). The night was divided into four equal intervals and a computer program calculated the mean respiratory rate for each interval as a function of state and age. During the first week of life group means of respiratory rates increased linearly with each interval in all states. A circadian pattern with lowered respiratory rates between 10:00 p.m. and 1:00 a.m. emerged at different ages in different sleep states. This pattern was first seen at one month of age in AS and IN, and at three months in QS. It was also observed in AW at three months of age, suggesting that the circadian rhythm is not solely an expression of the sleep wakefulness cycle. Feeding patterns contributed to but did not explain these observations.

Age Factors↗
PubMed1979

New endotracheal tube adaptor reducing cardiopulmonary effects of suctioning.

The continuous recordings of arterial oxygen saturation (SaO2) and beat-to-beat heart rate before, during, and after tracheobronchial suctioning were studied in eight preterm infants with severe RDS receiving mechanical ventilation. Two suctioning procedures were alternatively performed in each infant; In procedure A, disconnection of the ventilator and preoxygenation preceded suctioning; in procedure B, a special suction adaptor was used without ventilatory interruption or preoxygenation; 128 suctionings were performed with each procedure and the changes in heart rate (HR) and SaO2 during suctioning were compared. Although in both procedures, HR and SaO2 decreased during suctioning, the degree of bradycardia and arterial blood oxygen desaturation were significantly smaller in magnitude and shorter in duration during procedure B. These data indicate advantages of the suction adaptor in minimizing bradycardia and hypoxia from airway suction.

Bronchi↗
PubMed1979

Sleep apnea in normal kittens.

Apneic episodes in normal 10-, 20-, and 40-day-old kittens were assessed with polygraphic recordings. End expiratory apneas, usually preceded by somatic activity and/or augmented breaths, with durations less than 10 sec were observed in quiet sleep, active sleep, and transitions between states in all age groups. The highest apnea density was found at state transitions. Heart rate decelerations occurred before, during, and following apneas, but decelerations were not related to apnea duration. Combined central and obstructive components were associated with 9% of apneas in normal kittens.

Age Factors↗
PubMed1978

Influences of exogenous intake and nitrogen balance on plasma and brain aromatic amino acid concentrations.

In an effort to determine the sum of the factors influencing the plasma and brain concentrations of aromatic amino acids in rats with liver disease, rats with end-to-side portacaval shunts and their sham-operated controls were placed on various oral and intravenous diets by the techniques of parenteral nutrition. In sham-operated animals with normal hepatic function, the source of amino acids and their composition appeared to play little role in the plasma and brain aromatic amino acids and a derivative of brain tyrosine, octopamine. After end-to-side portacaval shunt, however, plasma and brain concentrations of aromatic amino acids were responsive to exogenous intake in the presence of hepatic impairment. In a group of rats with end-to-side portacaval shunt and presumed hepatic impairment, graded increments of protein equivalent were given with isocaloric hypertonic dextrose by the techniques of parenteral nutrition. When the animals achieved positive nitrogen balance, there were decreased levels in plasma and brain of the aromatic amino acids, phenylalanine and tyrosine, and a derivative of tyrosine, octopamine. A clear statistical relationship between plasma and brain tryptophan and nitrogen balance was not observed. The results suggest that in animals with hepatic impairment secondary to end-to-side portacaval shunt both exogenous intake and the level of catabolism (nitrogen balance) influence plasma and brain aromatic amino acids.

Amino Acids↗