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Biomedical subjects

M P Wailoo

Publications and source records attributed to M P Wailoo.

At least 19 recordsLinked to original sources
PubMed1996

Higher rectal temperatures in co-sleeping infants.

The effect on deep body temperature of infants co-sleeping (with either or both parents) is investigated in this case control study. Overnight continuous recordings of rectal temperature were made from 34 babies co-sleeping with one or both parents throughout the night and 34 infants matched for age, feeding regimen, parental smoking, thermal environment, sleeping position, and sex who slept alone. The co-sleeping infants had significantly higher rectal temperatures from two hours after bedtime, when the initial fall in sleeping body temperature was complete. The mean rectal temperature of co-sleeping infants between two and eight hours was 0.1 degree C higher than that of infants sleeping alone (p < 0.04). Given the very small variance in rectal temperature this probably reflects a considerable physiological difference between the two groups.

Analysis of Variance↗
PubMed1995

Prone sleeping infants have a reduced ability to lose heat.

The heat loss coefficients of a group of infants have been calculated and compared to see if there is a difference in the ability to lose heat between prone and non-prone sleeping infants. For a group of 43 infants aged 4-29 weeks, a simple mathematical model of exponential cooling in a body has been fitted to the fall in rectal temperature which occurs in infants at bedtime. One of the parameters yielded by the fitting process is the coefficient of thermal heat loss. After validation against the estimated heat loss from supine sleeping infants, the heat loss coefficient was compared at different sleep positions and gender. The mean heat loss coefficient, measured from the non-prone sleeping infants (0.269 W/degrees C, S.D. 0.197) agreed well with the value calculated for supine sleepers with the same tog levels (0.4 W/degrees C). Prone sleeping infants were found to have a considerably smaller heat loss coefficient which was approximately 60% of the value for non-prone sleeping infants (P = 0.000097). Female infants were found to have a heat loss coefficient that was approximately 70% of that of male infants but this gender difference was only significant (P = 0.025) for non-prone sleeping infants. These results suggest that infants sleeping in the prone position may be unable to lose heat as rapidly as those infants sleeping non-prone.

Body Temperature Regulation↗
PubMed1995

Lower body temperature in sleeping supine infants.

Night time rectal temperature recordings were made from 103 infants sleeping in their own home in different sleeping positions. In most cases sleeping position was verified by video monitoring throughout the night. In the period before an adult-like night time body temperature pattern appeared there was no significant effect of sleeping position upon night time body temperature, in line with previous reports. Once an adult-like night time temperature pattern appeared, infants sleeping supine reached significantly lower rectal temperatures than those sleeping prone or lateral. Babies sleeping supine moved significantly more during the night and were more likely to uncover their hands and arms. These findings suggest that supine sleepers are in a different physiological condition from those sleeping prone or lateral, which may be associated with their lower vulnerability to sudden unexpected infant death.

Body Temperature↗
PubMed1995

Urinary excretion of cortisol after immunisation.

Urinary cortisol excretion and rectal temperature were measured in 66 infants before and after immunisation against diphtheria, tetanus, pertussis, and Haemophilus influenzae type b. Immunisation produced a significant increase of rectal temperature the next night at all ages. Infants without an adult-like night time body temperature pattern had a significant increase in urinary cortisol excretion night and morning after immunisation. Once an adult-like night time body temperature pattern developed immunisation no longer significantly raised urinary cortisol output.

Age Factors↗
PubMed1995

Factors affecting rectal temperature in infancy.

The recordings of 1197 overnight rectal temperatures from infants of up to 24 weeks of age have been analysed with respect to 12 variables, including a number of risk factors for sudden infant death syndrome. Multivariable regression was used to identify if parental smoking, bottle feeding, sleeping position, and birth weight affect the overnight rectal temperature of infants. The rectal temperature, averaged over the period from three to five hours after the infants were put to bed, correlated well (R = 0.36) with the collected variables. An increase in the infant's age, birth weight, and the supine sleeping position all decreased the night time rectal temperatures. However, an increase in the night time room temperature, weight, and the combination of bottle feeding and parental smoking produced an increase in rectal temperature. The individual effects of bottle feeding and parental smoking were not significant. The results show that some of the major risk factors have the effect of raising the rectal temperature of sleeping infants.

Birth Weight↗
PubMed1994

Interactions between infant care practices and physiological development in Asian infants.

Asian infants are less likely to suffer cot death despite apparently higher prevalence of some risk factors. This paper compares the development of night time body temperature patterns in a small sample of Asian babies with the pattern already established for white infants, where babies who develop an adult-like night time temperature pattern later than usual share characteristics with victims of SIDS. The Asian infants had similar body temperature patterns to whites, but tended to develop the adult-like pattern later, not earlier as might have been expected. More Asian infants than white in our sample slept in the parental bed, and, before the adult-like body temperature patterns appeared, co-sleeping infants had higher body temperatures than those in their own cots. Asian infants slept in significantly warmer rooms than whites, but under similar amounts of bedding. These studies do not therefore reveal any physiological difference between Asians and whites which might account for low vulnerability to cot death, indeed, if anything the reverse.

Adult↗
PubMed1994

Body temperature changes before minor illness in infants.

This study aimed to examine the overnight temperature pattern of babies during the prodromal phase of minor illnesses. The overnight rectal temperature pattern of 123 babies was recorded weekly from about 6 to at least 16 weeks old, while parents maintained detailed records of signs of illness. By analysis of patterns of signs and visits to the general practitioner, 86 periods of minor illness were identified, mostly upper respiratory tract infections, though it was not usually possible to identify the infection by conventional virology. Data were analysed separately for babies who had developed an adult-like night time temperature pattern and those who had not. In both groups, obvious signs of illness were preceded by a disturbance of night time temperature pattern. Temperature was significantly raised over control weeks, though few babies were clinically febrile. The greatest temperature disturbances were seen in the three days before illness, though some disturbances were seen up to seven days before. A similar disturbance of temperature was seen the night after diphtheria, pertussis, and tetanus immunisation, and individual responses to natural infection and immunisation were well correlated, suggesting that the temperature change is more a function of the host response than the infecting agent.

Body Temperature↗
PubMed1992

Factors affecting the development of night time temperature rhythms.

The rectal temperature of 26 infants between 6 and 16 weeks old was monitored continuously for one night each week. Rectal temperature always decreased with sleep but the minimum temperature attained changed with age. Some time between 8 and 16 weeks old the minimum sleeping rectal temperature decreased abruptly from around 36.8 degrees C to around 36.4 degrees C. This change was complete within one week and did not normally revert unless the infant became ill. Some infants changed as early as 8 weeks old, others not until 16 weeks. Breast fed infants changed significantly earlier than bottle fed infants. Girls changed significantly earlier than boys. First born infants changed significantly earlier than second or subsequent infants. Early changes were significantly more likely to be sleeping lateral or supine, and to have older mothers. They tended to come from more affluent families. There was no association between the time of change and the thermal environment in which the infant slept or the number of episodes of minor illness in the early weeks of life.

Aging↗
PubMed1991

Development of night time temperature rhythms over the first six months of life.

Continuous recordings of night time rectal temperature were made at regular intervals over the first six months of life in 49 babies. In the first two weeks of life rectal temperature changed little overnight, but by 6 weeks of age rectal temperature at bedtime was significantly higher than later in the night. By around 12 weeks of age sleeping deep body temperature fell below 36.5 degrees C, and by 16 weeks of age all babies exhibited a consistent rhythm of rectal temperature. This fell by about 0.8 degrees C within two hours of bedtime, and then remained low until an hour or two before waking. As babies got older the mean interval between bedtime and first disturbance of parents got longer. Sleeping rectal temperature fell below 36.5 degrees C at about the time babies slept for seven hours. From 6 weeks of age, as individual baby's rectal temperatures fell more with sleep, sleep got longer.

Body Temperature↗
PubMed1991

Sleeping position and rectal temperature.

The effects of sleeping position upon body temperature were assessed by continuous monitoring of rectal temperature in 137 babies sleeping at home under conditions chosen by their parents. There were three groups of subjects: (1) normal babies aged 12-22 weeks whose temperature rhythms were developed, (2) normal babies aged 6-12 weeks who were developing their night time temperature rhythms, and (3) babies the night after diphtheria, pertussis, and tetanus immunisation, whose temperature rhythms were disturbed. Sleeping in the prone position was not associated with higher rectal temperatures at any time of night in young babies, nor did it exaggerate the disturbance of rectal temperature rhythm after immunisation. In older normal babies the prone position did not disturb rectal temperature in the first part of the night, though prone sleepers warmed a little faster prior to walking, especially in warm conditions. Prone sleepers were, however, born earlier in gestation and tended to be of lower birth weight. Normal babies can therefore thermoregulate effectively whatever their sleeping posture, even in warm conditions, though the prone position may make it slightly more difficult to lose heat. It is difficult to see how the prone position, even interacting with warm conditions, could induce lethal hyperthermia in otherwise normal babies. Perhaps the prone position is associated with other risk factors for sudden infant death syndrome.

Bedding and Linens↗
PubMed1990

Use of thermographic imaging to study babies sleeping at home.

Two 3 month old infants sleeping under different thermal conditions were found to maintain similar deep body temperatures. Thermographic imaging suggested that though the uncovered head is the main source of heat transfer, other parts of the body such as the hands may be used when necessary.

Body Temperature↗
PubMed1990

Rectal temperature of normal babies the night after first diphtheria, pertussis, and tetanus immunisation.

Continuous rectal temperature recordings were made from 32 babies the night after their first diphtheria, pertussis, and tetanus immunisation and compared with recordings made before immunisation. Tog values of clothes and wrapping and room temperatures were also recorded. We found that immunisation the day before disturbs the normal night time rhythm of deep body temperature. The rectal temperature of immunised babies was significantly higher than non-immunised babies from two hours into the night. We also found that there were considerable individual variations in the extent of disturbance of temperature rhythm. They were not correlated with thermal environment. There is no reason to suppose that these mild physiological responses to immunisation are in any way harmful.

Body Temperature↗
PubMed1990

Factors influencing the body temperature of 3-4 month old infants at home during the day.

Continuous recordings of rectal temperature were made from 40 normal infants, aged 3-4 months, at home during two days of normal activities. We found that the rectal temperature of a normal, healthy baby may vary from 36.0 degrees C at night to 37.8 degrees C during active periods of the day. During daytime sleep rectal temperature fell, but to a lesser extent, and for less time than during night time sleeps. Feeds raised the temperature unless the baby slept, when they reduced the rate of fall of temperature. Bottle feeds affected temperature more quickly than breast feeds. The changes in temperature during sleep and after feeds were independent of the room temperature or thermal insulation of clothing and wrapping.

Body Temperature↗
PubMed1990

Disturbed nights and 3-4 month old infants: the effects of feeding and thermal environment.

Parents completed a prospective diary of a night's sleep for 87, 3-4 month old infants at home whose body temperatures were continuously recorded. We found that about half of the babies disturbed their parents in the night. Breast fed babies were more likely to wake parents in the middle of the night. The babies who disturbed their parents in the middle of the night were significantly more heavily wrapped in significantly warmer rooms. We suggest that discomfort from efforts at active thermoregulation in warm environments may lead some babies to disturb their parents at 'unsocial hours'.

Body Temperature↗
PubMed1989

Sleeping body temperatures in 3-4 month old infants.

Rectal, skin, and ambient temperatures were continuously recorded overnight from 3-4 month old normal infants in their home cots under conditions of room temperature and wrapping chosen freely by parents. It was found that rectal temperature was above 37 degrees C when infants were put down, but fell rapidly to 36.4 degrees C within one and a half hours, then stabilised for a few hours before rising steadily. This pattern was tied more closely to the time of putting down than time of day. The extent and rate of temperature fall did not correlate with any feature of the thermal environment. We also found that skin temperature changed much less than rectal temperature over the night, and for the first two hours in the cot there was no relation between skin and rectal temperature. There is therefore a well organised, endogenous rhythm of temperature in 4 month old infants.

Body Temperature↗
PubMed1989

The thermal environment in which 3-4 month old infants sleep at home.

The thermal insulation of clothing and wrapping (tog value), room temperature, and body temperature was measured for 3-4 month old infants sleeping in their home cots under conditions chosen freely by parents during a cold winter. We found that ambient temperature averaged 18.4 degrees C when infants were put down, but fell by an average of 4.4 degrees C during the night. Minimum room temperature correlated with outside temperature, but most rooms were heated to some degree; smaller babies were kept in warmer rooms. The tog value of clothing before putting the baby down averaged 5.1, supplemented by 9.6 tog units of wrapping in the cot--a 188% increase for a 4.4 degrees C drop in temperature. Total tog of clothing and wrapping correlated negatively with minimum room temperature; smaller born babies tended to be more heavily wrapped. Despite the large increase in insulation in the cot, most babies maintained normal body temperatures.

Body Temperature Regulation↗