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Biomedical subjects

J Milerad

Publications and source records attributed to J Milerad.

At least 19 recordsLinked to original sources
PubMed1998

Objective measurements of nicotine exposure in victims of sudden infant death syndrome and in other unexpected child deaths.

OBJECTIVE: Self-reported maternal smoking is associated with a dose-related-increase in the risk of sudden infant death syndrome (SIDS). The aim of this study was to measure objectively whether victims of SIDS are more exposed to tobacco smoke before death than infants who die unexpectedly of other causes. DESIGN: Continine levels in pericardial fluid were used as an indicator of exposure. Levels > 5 ng/mL indicated significant exposure, and levels > 20 ng/mL indicated heavy exposure. Samples were obtained from all sudden deaths in children < 7 years of age that occurred from 1990 through 1993 in southeastern Norway. Twenty four infants died of SIDS, 12 infants of infections, and 9 of accidents (median age 4.5, 5, and 35 months, respectively). RESULTS: Compared with the age-matched infectious deaths, a significantly higher proportion of victims of SIDS had been significantly (92% vs 67%) or heavily exposed (25% vs 0%) to nicotine, (P < .05). Median cotinine levels in infants with SIDS, 15.8 ng/mL, were significantly higher than in infants who had infectious deaths 7.1 ng/mL (P < .003) but were comparable to those of accident victims (12.9 ng/mL, not significant). CONCLUSIONS: Victims of SIDS are more often and more heavily exposed to tobacco smoke doses before death than are infants who have sudden infectious deaths. Accidental death in infancy and childhood is often associated with a significant exposure to nicotine.

Humans↗
PubMed1998

Sleeping position, breastfeeding, bedsharing and passive smoking in 3-month-old Swedish infants.

Parents of 1028 infants who attended community-based infant health clinics were interviewed concerning infant sleeping position, feeding habits, bedsharing and passive smoking at 3 months of postnatal age. In addition, they were asked to state which source of information had mainly influenced them in the choice of the sleeping position. Fifteen per cent of the infants were regularly laid to sleep in the prone position, compared with 72% (1991) before official guidelines concerning infant sleeping position were issued. The overall prevalence of exclusive breastfeeding was 70.4%. Prevalence of maternal smoking was 17.9% and 22.8% of the infants were regularly bedsharing with the parents. Those mothers who did not comply with official recommendations regarding infant sleeping position were also less likely to follow other recommendations concerning infant care practices. Prone sleeping infants were more likely to be formula fed and exposed to passive smoking, and hence associated with additional risk factors for sudden infant death syndrome.

Breast Feeding↗
PubMed1998

A case-control study of smoking and sudden infant death syndrome in the Scandinavian countries, 1992 to 1995. The Nordic Epidemiological SIDS Study.

AIM: To establish whether smoking is an independent risk factor for sudden infant death syndrome (SIDS), if the effect is mainly due to prenatal or postnatal smoking, and the effect of smoking cessation. METHODS: The analyses were based on data from the Nordic epidemiological SIDS study, a case-control study with 244 cases and 869 controls. Odds ratios were computed by conditional logistic regression analysis. RESULTS: Smoking emerged as an independent risk factor for SIDS, and the effect was mainly mediated through maternal smoking in pregnancy (crude odds ratio 4.0 (95% confidence interval 2.9 to 5.6)). Maternal smoking showed a marked dose-response relation. There was no effect of paternal smoking if the mother did not smoke. Stopping or even reducing smoking was beneficial. SIDS cases exposed to tobacco smoke were breast fed for a shorter time than non-exposed cases, and feeding difficulties were also more common. CONCLUSIONS: Smoking is an independent risk factor for SIDS and is mainly mediated through maternal smoking during pregnancy. Stopping smoking or smoking less may be beneficial in reducing the risk of SIDS.

Breast Feeding↗
PubMed1998

The divergent ventilatory and heart rate response to moderate hypercapnia in infants with apnoea of infancy.

BACKGROUND: Inspired CO2 is a potent ventilatory stimulant exhibiting a paradoxical inhibitory effect on breathing at high concentrations. Severe respiratory depression as a result of CO2 rebreathing during sleep has been implicated as a possible trigger factor in sudden infant death syndrome (SIDS). OBJECTIVE: To investigate the ventilatory and heart rate (HR) responses to inhaled CO2 in infants with apnoea of infancy, a group believed to be at increased risk of SIDS. STUDY DESIGN: Thirty one infants with severe sleep related apnoea, 31 infants with mild recurrent apnoea, and 31 age and sex matched controls for the infants with severe sleep related apnoea were studied. HR was computed from digitised RR intervals, "ventilation" was recorded by inductance plethysmography, and PCO2 and PO2 were monitored by transcutaneous electrodes. The ventilatory and HR responses to CO2 were expressed as percentage increase in ventilation and change in HR/unit change in transcutaneous PCO2. RESULTS: The mean increase in transcutaneous PCO2 during CO2 challenge (0.45 kPa = 3.4 mm Hg) resulted in a mean increase in ventilation of 291%/1 kPa (7.3 mm Hg) increase in transcutaneous PCO2, with no difference between the groups. A significant difference between infants with severe sleep related apnoea and mild recurrent apnoea versus controls (p < 0.02, p < 0.01, respectively) was found in their HR response to CO2 challenge: HR decreased in 12 severe sleep related apnoea infants and 10 infants with mild recurrent apnoea, but only in two controls. CONCLUSION: Infants with apnoea of infancy frequently show a paradoxical decrease in HR during CO2 challenge, possibly because of an insufficient ability to mobilise cardiovascular defence mechanisms when challenged with hypercapnia.

Apnea↗
PubMed1998

Incidence of cleft lip and palate and risks of additional malformations.

OBJECTIVE AND METHODS: Children with cleft lip and/or palate (n = 251) born between 1991 and 1995 in the county of Stockholm, Sweden, were studied with reference to incidence and rate ratios (RRs) of different types of clefts, gender, birth weight, mother's age, and length of pregnancy. Children who had clefts and additional malformations were compared with children who had clefts but no additional malformations. RESULTS: The incidence of clefts was 2.0/1000 live births, and it was higher among males than among females. The RR, an index of relative risk, was 1.58. The main groups, children with isolated cleft lip, children with cleft lip and palate, and children with isolated cleft palate, showed similar incidence values (0.6-0.7/1000 live births). Children with bilateral clefts had an incidence of 0.3/1000 live births. Additional malformations were found in approximately every sixth newborn with a cleft when children with Robin sequence were excluded. There was a tendency for newborns with bilateral clefts to have additional malformations (RR = 1.36; confidence interval = 0.74-2.49). Children with clefts and additional malformations had lower birth weight and were born earlier than children with clefts only. CONCLUSION: Preterm cleft children with low birth weight should be screened for the presence of other birth defects.

Adult↗
PubMed1997

Sudden infant death and prevalence of whooping cough in the Swedish and Norwegian communities.

UNLABELLED: Whooping cough (WC) has been suggested to be a trigger factor for sudden infant death (SID), the proposed mechanism being unrecognised hypoxaemic episodes. In contrast to Norway, Sweden ceased its immunisation programme against Bordetella pertussis (BP) in 1979. We investigated the relation between SID mortality and the prevalence of BP during 1983 to 1988, by month, in the two ethnically and socially similar, bordering countries adopting different strategies towards WC. In addition, the greater Stockholm area was analysed. For both countries the prevalence of BP was collected from monthly reports by regional health officers. SID mortality rates were provided by the Norwegian Central Bureau of Statistics and the SID registry at the Swedish National Board of Health and Welfare. The relation between SID mortality rate and prevalence of WC, by month, was analysed by linear regression. In addition, the consistency of seasonal fluctuations was investigated by analysing the covariance between average, pooled, monthly values of the two variables. SID mortality rate followed significantly the monthly prevalence of BP in Sweden (P < 0.01) and Stockholm (P < 0.0001) during the study period. In Norway there was a significant correlation only during the epidemic outbreak of WC (P < 0.05), but not for the whole study period. When controlling for seasonality a significant correlation remained in the urban area of Stockholm (P < 0.05). CONCLUSION: It is suggested that covariations between WC and SID mortality rate may be related to transmission rate and immunisation status of the investigated population.

Analysis of Variance↗
PubMed1997

The decline in the incidence of SIDS in Scandinavia and its relation to risk-intervention campaigns. Nordic Epidemiological SIDS Study.

A prospective case-control study of sudden infant death syndrome (SIDS) in Norway, Denmark and Sweden between September 1, 1992 and August 31, 1995 comprised 244 cases and 869 matched controls. After the introduction of risk-intervention campaigns, the SIDS incidence decreased from 2.3/1000 live births in Norway, 1.6 in Denmark and 1.0 in Sweden to 0.6/1000 or fewer in all the Scandinavian countries in 1995. The decrease paralleled a decline in the prone sleeping position and there was an accompanying parallel fall in total postneonatal mortality in all three countries. Thus, the risk-reducing campaigns for SIDS have been successful not only in Norway and Denmark, starting from relatively high incidences, but also in Sweden, starting from a low incidence. During the study period, a gradual increase was observed for the effects of prone sleeping, smoking and bottle-feeding as risk factors for SIDS.

Case-Control Studies↗
PubMed1997

Heart rate response profiles during head upright tilt test in infants with apparent life threatening events.

Sympatheticovagal imbalance causing episodes of severe bradycardia has been suggested as a cause of apparent life threatening events (ALTEs). The autonomic control of the heart rate in 18 infants with ALTEs and 12 controls was evaluated by the head upright tilt test. Five different heart rate response profiles (compared with the baseline) were observed during the tilt: (1) increase followed by a decrease and return to baseline; (2) sustained increase; (3) decrease followed by an increase and return to baseline; (4) sustained decrease; (5) no change. Eighty eight per cent of controls responded with heart rate increase followed by decrease or sustained increase compared with 55% of infants with an ALTE; a significantly greater proportion of infants with ALTEs than controls responded with heart rate decrease or no change in rate (45% v 8%). This altered reaction during a head upright tilt test may be an expression of an underlying autonomic dysfunction in infants who have experienced an ALTE.

Case-Control Studies↗
PubMed1996

Breath-by-breath determinations of airway occlusion pressure in the developing lamb.

The ventilatory effects of breath-by-breath measurements of airway occlusion pressure, i.e., airway pressure determined 100 ms after initiation of inspiration (P0.1) were evaluated in seven lambs studied sequentially between 7 and 28 days after birth. P0.1 was determined by computer-aided, on-line regression analysis of the inspiratory pressure versus time (dP/dt) by means of a pneumatic occlusion valve that allowed occlusion times to vary in proportion to respiratory rate. No significant changes were found in minute ventilation, tidal volume, respiratory rate or end-tidal CO2 concentration when the valve was operating as a oneway valve (opening pressure 0.02 kPa or 0.2 cmH2O) compared to when in occlusion mode [opening pressure 0.18-0.2 kPa or 1.8-2.0 cmH2O, mean occlusion time 44 (25) ms]. The calculated P0.1 values correlated well with those obtained from manual occlusions (r = 0.87, P < 0.0001). This new technique, which detects and discards irregular or non-linear (r < 0.95) inspiratory pressure profiles, enables breath-by-breath determinations of inspiratory drive in rapidly breathing lambs with minimal impact on respiratory pattern and ventilation.

Aging↗
PubMed1995

Commentary on neonatal ECMO: a North American and Scandinavian perspective.

Randomized clinical trials have become the cornerstone of clinical decision making in neonatal medicine. The need to establish the safety and efficacy of different treatment regimens by means of an unbiased approach has led to the formation of state-agency supported and voluntary national and international networks. These neonatal networks have greatly facilitated the organization of randomized multicenter trials. Most studies aimed to evaluate specific treatment alternatives for common disorders (e.g. surfactant therapy for RDS and iv gammaglobulins for prevention of nosocomial infections are particularly well suited for a randomized clinical trial). However, appraisal of alternative therapies for rare conditions with excessive mortality and high risk for later sequelae is limited by a number of practical and ethical considerations. In view of the complexity of the problems involved it is hardly surprising that only one recent head-to-head trial of conventional therapy versus ECMO has to our knowledge been published (39). In this investigation 28 full-term infants fulfilling standard ECMO criteria were randomly assigned to be transported for ECMO or to receive conventional treatment available on-site. Fourteen of the 15 infants (93%) referred for ECMO survived compared with 7 of 13 (53%) treated conventionally. The long-term outcome was comparable in both groups. These data support previous reports of significantly better survival following ECMO treatment. However, the notion of > 80% mortality on continuation of conventional therapy in this critically ill population may need to be reassessed. HFO is today part of "conventional" therapy in many centers, surfactant is used routinely and a combination of NO and HFO is being evaluated in several clinical trials (57).(ABSTRACT TRUNCATED AT 250 WORDS)

Extracorporeal Membrane Oxygenation↗
PubMed1995

Nicotine attenuates the ventilatory response to hypoxia in the developing lamb.

Decreased ability to generate a hyperventilatory response to hypoxemia is believed to be an important mechanism in the pathophysiology of sudden infant death syndrome, and maternal smoking is a leading risk factor. To investigate whether there may be a link between these two observations, we studied five lambs at mean ages of 7, 17, and 27 d to determine the effects of an i.v. infusion of nicotine (0.5 microgram/kg/min) on ventilation when peripheral chemoreceptor activity was stimulated by hypoxia (0.1 FiO2) or briefly inhibited by hyperoxia. Ventilatory measurements were performed using a computer-aided occlusion valve device which permitted breath-by-breath determinations of inspiratory occlusion pressures (P0.1) and minute ventilation. Nicotine attenuated the early ventilatory response to hypoxia (min 1, 2, and 3 of the test) by 8, 26, and 37%, respectively, at the age of 7 d (analysis of variance overall, p < 0.05), by 23%, 23 and 37% at 17 d (p = NS) and by 40, 45, and 37% at 27 d (p < 0.05). The decrease in ventilation in response to hyperoxia during the control study without nicotine was 18, 35, and 34% at 7, 17, and 27 d, respectively. Nicotine caused a greater decrease in the response: 31, 45, and 46%, respectively, (p < 0.05 at 27 d). The paradoxical effects of nicotine, attenuation of the ventilatory response to hypoxia and augmentation of the response to hyperoxia, suggest that nicotine altered peripheral chemoreceptor oxygen sensitivity and most likely also affected central processing of the chemoreceptor input.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1994

Nicotine and cotinine levels in pericardial fluid in victims of SIDS.

We have analyzed the levels of nicotine and cotinine in pericardial fluid in 24 consecutively autopsied cases of sudden unexpected death in infants aged one to six months. Our aim was to determine to what extent victims of sudden infant death may have been exposed to passive smoking near the time of death. Sixteen of the decreased infants were classified as SIDS at autopsy. Other contributing causes of death, predominantly infections, were found in eight cases. Eight infants (30%) had cotinine levels less than 2 ng, indicating that no significant exposure to nicotine had occurred near the time of death. Of the remaining 70%, five had been moderately exposed, seven markedly exposed and four heavily exposed (cotinine levels 2-10 ng, 10-50 ng and more than 50 ng, respectively). Since only 18% of Swedish women smoke after childbearing we conclude that nicotine exposure in infants who died suddenly was much higher than one would otherwise expect. It is hypothesized that high concentrations of nicotine and nicotine metabolites around the heart may affect cardiac function and thus play a role in the mechanisms causing SIDS or other categories of sudden unexpected death.

Cotinine↗
PubMed1993

SIDS outdoors and seasonality in Sweden 1975-1987.

In order to link the reported increasing incidence of SIDS in Sweden to environmental or other risk factors, we compared birth records and circumstances of deaths in infants who died in 1975-1977 with those who died a decade later, 1985-1987. The number of liver births differed by only 6850 in these two periods. Data were acquired from autopsy records of the decreased infants and matched with their respective birth certificates which were obtained from the National Board of Health and Welfare. The reported postperinatal incidence of SIDS increased from 0.51 per 1000 in 1975-1977 to 0.93 per 1000 in 1985-1987. No significant differences in boy/girl ratio, birth weight, gestational age or age at death were found in the two periods. While the number of infants who died at night indoors in their own bed remained almost unchanged, the number of infants who died outdoors in baby carriages during the cold season increased almost four-fold. The observed increase in incidence could, to a large extent, be related to the increase in outdoor deaths. We speculate that increased incidence of smoking among young women as well as other changes in lifestyle may have been contributing factors.

Cold Temperature↗