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Biomedical subjects

T G Matthews

Publications and source records attributed to T G Matthews.

At least 37 records · Page 2Linked to original sources

The "nasal cycle" in infants.

In 93 of 100 infants there was a marked difference in the measured end-tidal carbon dioxide (CO2) level between nasal airways during quiet sleep (4.88 Kpa V 3.3 Kpa P less than 0.001). It is suggested that partial nasal obstruction is common in infants. Nasal airway resistance is increased by mucosal swelling, is assymetric, regularly alternates between sides (the nasal cycle), and is under autonomic control. End tidal carbon dioxide values are widely measured as part of an assessment of respiratory control and risk of sudden infant death syndrome. The preferential use of one nasal airway must be taken into account in assessing such results.

Airway Resistance↗

Medication side effects of dental interest.

Many dental patients require continuing medication. With some, the medications will have side effects that have an oral or perioral manifestation. Commonly prescribed medications and their dental side effects are listed. This information may aid patients who have oral symptoms unrelated to the needed dental care.

Drug-Related Side Effects and Adverse Reactions↗

Impact of heating and air conditioning system operation and leakage on ventilation and intercompartment transport: studies in unoccupied and occupied Tennessee Valley homes.

Forced-air heating and air conditioning (HAC) systems caused an average and maximum increase in air infiltration rates of 1.8- and 4.3-fold, respectively, during brief whole-house studies of tracer gas decay in 39 occupied houses. An average increase in air infiltration rate of 0.33 +/- 0.37 h-1 corresponded to an incremental air leak of 240 m3/h, based on approximate house volume. More detailed tracer gas decay studies were performed in basement, kitchen and bedroom locations of six homes with low air infiltration rates (i.e., less than 0.25 h-1). The HAC mixed the indoor air efficiently between measurement sites. HAC operation also caused 1.1- to 3.6-fold increases in air infiltration rates, corresponding to absolute increases of 0.02 to 0.1 h-1. In an unoccupied research house, three-fold increases in average air infiltration rate with HAC operation (i.e., from 0.13 to 0.36 h-1) were reduced to two-fold (i.e., from 0.10 to 0.18 h-1) by sealing the external HAC unit and crawlspace ductwork system. This sealing also resulted in a 30 percent reduction in crawlspace-to-indoor transport rates with the HAC turned on. Blower door tests indicated a less than 20 percent reduction in house leakage area.

Air Conditioning↗

Transportation of newborn infants.

The benefit of an organized neonatal transport system is well established. Over a 30 month period, January 1987 to June 1989, 172 babies were transported to the Dublin maternity hospitals. Birth weights ranged from 640 to 5,180g 106 (62%) were less than 37 weeks gestation. Indications for transport included respiratory distress syndrome (54), prematurity only (43), convulsions and/or neurologic dysfunction (23), jaundice (11) and apnoea (11). One hundred and sixty-eight were transferred by ambulance and four by helicopter. Twenty travelled more than 100 miles. Forty (23%) received assisted ventilation during transport. On arrival 37 (21%) had temperature less than 36 degrees C; 22 (13%) had blood sugar less than 2.2 m mol/l and 34 (20%) had arterial ph less than 7.25. Fifty per cent of referral letters had incomplete information. Treatment and care given en route was recorded in only 28 babies. Twenty-four babies (14%) died. Infants who died were more likely to have been of low birth weight, travelled a long distance, been hypothermic, had poor arterial gases, had blood sugars less than 2.2 m mol/l, and had poor referral letters. This review indicates that death and morbidity continue to be associated with the present system of postnatal transfer of newborn infants. The urgent need for an organized neonatal transport service remains unmet.

Emergency Medical Services↗

Autonomic dysfunction at different ambient temperatures in infants at risk of sudden infant death syndrome.

Autonomic function was assessed by measuring the heart rate and blood pressure responses to a change from the horizontal to upright posture at various ambient temperatures in four groups of infants aged 8-12 weeks: 30 infants who had suffered a well-defined unexplained apparent life-threatening event (ALTE); 8 infants who had suffered a cyanotic attack; 24 healthy infants with a sibling who had died from sudden infant death syndrome (SIDS); and 17 healthy infants. Autonomic dysfunction was uncommon in the control group; no infant showed an abnormal heart rate response to postural change (R to R interval maximum/minimum ratio less than 1.0) and a postural fall in blood pressure of greater than 10% occurred in only 1 infant. In contrast, in the ALTE group 9 of 26, 9 of 30, and 4 of 22 infants showed an abnormal heart rate response and 20 of 26, 14 of 30, and 10 of 22 a greater than 10% fall in blood pressure on postural change at 20 degrees C, 25 degrees C, and 30 degrees C, respectively. 1 ALTE infant died of SIDS 14 h after showing an RR max/min ratio of 0.8 and a postural fall in blood pressure of 11% and 14% at 20 degrees C and 30 degrees C. Autonomic function testing should become part of the clinical evaluation of infants at high risk of a sudden unexpected death.

Autonomic Nervous System Diseases↗

Infant care: the value of the six week check.

A review of the routine six week post-natal examination of the well-baby was performed. Eighty-one percent of infants born in the Rotunda attended for a hospital based review during the study period and 42% of these had experienced some problem during the six weeks from birth (rashes 20%, snuffles 10.7%, irritability 7.6% and eye infections, constipation, diarrhoea, vomiting, cyanotic/breath holding episodes). These problems were dealt with by the hospital outpatient department (55%), the mothers themselves (30%), general practitioners (12.5%) and public health nurses (2.5%). Significant problems not detected at birth were present in 12 infants (3%) and eight infants (2%) required hospital admission. This review illustrates a relatively low rate of problems not previously detected and that the majority of problems arising in the first six weeks of life require advice alone. There is also clearly scope for improving the community based services and increasing their involvement in this aspect of infant health.

Community Health Services↗

Cost of neonatal intensive and special care.

A detailed costing of neonatal intensive and special care was made for the year 1986 at the Rotunda Hospital. Cost was expressed at 1986 prices in punts. There was 1,364 admissions including external transfers giving a total of 10,086 bed days, divided into 1,044 intensive care and 9,042 special care bed days. The total cost of intensive and special care was 1,342,500 pounds. Costs per inpatient day were 288 pounds for intensive and 115 pounds for special care. Sixty percent of the intensive care bed days were used by infants weighting less than 1,500 g birth weight and 93% by infants less than 2,500 g birth weight; this emphasizes the effect of population mix on resource use. The average cost of intensive care survivors by birth weight were: less than 1,000 g - 16,226 pounds (8,052 pounds-23,535 pounds); 1,000 g-1,499 g - 13,412 pounds (1,898 pounds-22,456 pounds); 1,500 g-2,499 g - 8,864 pounds (633 pounds-17,666 pounds); 2,500 g + - 5,123 pounds (384 pounds-12,636 pounds). The average cost of all admissions to special or intensive care was 984.24 pounds. Using this figure (984.24 pounds) and assuming that 13% of all births in 1986 required special or intensive care the total health care expenditure on neonatal special or intensive care in 1986 amounts to 8.03 million pounds of a total Department of Health budget of 1,269 million pounds. By allocating infants to the currently used neonatal diagnostic related groupings (DRGs) and assigning costs at 1987 US reimbursement levels, the total cost to the Rotunda would be 1,878,750 pounds punts. The current level of DRGs derived from the reimbursement rates in the United States which is insufficient to meet the actual cost incurred there, is 40% greater than current total funding of neonatal intensive and special care in the Rotunda. Current funding levels in the United Kingdom are 13% to 80% greater than in the Rotunda.

Costs and Cost Analysis↗

Hypothermia and sudden infant death syndrome.

We recently reported an association between recurrent episodes of severe apnoea requiring vigorous resuscitation for which no cause could be found and episodic hypothermia. Two similar cases are now reported that give further evidence of a link between hypothermia and acute life threatening episodes of apnoea.

Apnea↗

Neonatal seizures: the Dublin Collaborative Study.

Asphyxial seizures occurred in 89 of 101,829 infants born alive at term (0.87/1000) in three large maternity hospitals from January 1980 to December 1984. These seizures were significantly associated with antenatal complications, primiparity, and prolonged pregnancy. Meconium staining of the amniotic fluid was also associated with asphyxial seizures, but there were high false positive (11%) and false negative (50%) rates. Fifteen of the infants who had seizures died (18%) and 21 (25%) were handicapped at 1 year. Outcome was most successfully predicted by the way the infant was feeding at 1-2 weeks. All infants taking more than half their estimated requirements by mouth at 1 week were normal, and those still being fed by tube at 2 weeks were handicapped.

Asphyxia Neonatorum↗