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Biomedical subjects

H Jeffery

Publications and source records attributed to H Jeffery.

24 records · Page 2Linked to original sources
PubMed1981

New methods to separate artifacts from normal and defective breathing patterns in different sleep-states, if infants are monitored at home.

Respiratory and cardiac monitoring was undertaken in the home for seven months in an infant at increased risk for cot-death (SIDS). The infant was a surviving non-identical twin of a SIDS sibling. In hospital, clinical and cardio-respiratory studies during sleep were normal. Analysis of eleven 24-hour tape-recordings showed that many of the alarms at home were the result of technical problems. Suspected apnoeas were identified initially from an oscilloscopic display of the original waveforms and from a compressed-record and histogram of the computed breath-to-breath intervals. Expanded pen-recordings confirmed some, but not all, of these suspected apnoeas (greater than 15s). The results indicate (i) the importance of verifying apnoeic episodes; (ii) the value of 24-h compressed recordings for identifying and timing the sleep cycles and their possible relationships to breathing defects; (iii) the need for improved instrumentation; (iv) the dangers of evaluating clinical prognosis or research from parental diaries.

Diseases in Twins↗
PubMed1977

Deafness after bacterial meningitis.

Seventeen children with previous bacterial meningitis and 17 sib controls were examined clinically and otoscopically. They were also tested with air-conduction and bone-conduction audiometry and evaluated by tympanometry. There were no major neurological abnormalities and few otoscopical signs of ear disease. 21% of the ears showed abnormalities on air-conduction audiometry but all were normal on bone-conduction audiometry. 30% had abnormal middle-ear pressures (more negative than 100 mm water) on tympanometry and 7% had abnormal compliance of the drum. There were no significant differences on any test between the postmeningitis children and the sib controls. Population studies have confirmed that minor hearing loss due to middle-ear dysfunction is common in children, but is probably temporary in most of them. We have found no excess of middle-ear dysfunction and no sensorineural deafness in these postmeningitis children, but other workers have shown that nerve deafness may occur in association with clinical neurological damage. However, much of the deafness attributed to bacterial meningitis in other studies may well reflect population variability.

Child↗
PubMed1977

Early neonatal bacteraemia. Comparison of group B streptococcal, other Gram-positive and Gram-negative infections.

All cases of neonatal bacteraemia associated with clinical illness occurring at Hammersmith Hospital, over a 9-year period, 1967-1975 inclusive, have been reviewed. The infants studied were those born in the hospital's maternity unit and those admitted from other hospitals from a wide area round London who were ill or of low birthweight. Positive blood cultures occurred in 91 infants, 47 of them in the first 48 hours of life. These 47 infants were analysed separately and divided into three groups, 13 with group B streptococcal infections, 11 with other Gram-positive infections, and 23 with Gram-negative infections. There were no significant differences in birthweight or gestation, in mortality, in incidence of clinically diagnosed respiratory distress syndrome or recurrent apnoea, or in the need for mechanical ventilation between the three groups. The age at which a diagnosis of infection was suspected, and the age at death were both significantly earlier in the group infected with group B streptococcus than in those obtained with other organisms (P less than 0-01 for both comparisons). There were no significant differences in the incidence of hyaline membrane formation or pneumonia seen at necropsy among the three groups. In some of the earliest deaths in the Gram-negative bacteraemic group, Gram-negative rods comprised the bulk of the hyaline membrane as did cocci in the group B streptoccal group.

Age Factors↗
PubMedDate not supplied

Autonomic reflexes in preterm infants.

Some autonomic nervous reflexes often tested in adult medicine have been studied in 21 preterm infants (25-37 gestational weeks). The aim was to develop such tests for preterm infants and see if there were any differences in babies with recurrent apnea and bradycardia and babies who had been exposed to sympathicolytic drugs before birth. To test sympathetic nervous activity the peripheral vascular resistance was measured before and during 45 degrees of head-up tilting. To test parasympathetic nervous activity the degree of bradycardia was measured in response to cold face test (application of an ice-cube on the fore-head) and laryngeal stimulation with saline. Finally the heart rate changes after a sudden noise (85 dB) were studied as an indicator of both sympathetic and vagal activity. The peripheral resistance was found to be relatively low in these preterm infants, particularly in some infants tested at the postnatal age of about two months. Heart rate and mean blood pressure did not change during tilting, while the peripheral resistance increased significantly mainly due to lowered limb blood flow. The median decrease of the heart rate during the cold face test was 20.0% and during laryngeal receptor stimulation 23.7%. The sudden noise usually caused a biphasic heart rate response. An autonomic nervous reflex score was calculated and found to be negative (parasympathetic) in infants with recurrent prolonged apnea and bradycardia and positive in infants with clinical signs of increased sympathetic nervous activity.

Apnea↗