Changes in body temperature and urinary cortisol after routine immunization in babies with intrauterine growth retardation

Aim : To investigate whether infants with intrauterine growth retardation (IUGR) experience different changes in temperature and cortisol excretion after routine immunization compared with normal healthy infants. Methods : Overnight deep body temperature and urinary cortisol to creatinine ratios were measured on the night after immunization and a control night in normal and IUGR infants. Results : In 60 normal infants, first vaccination at about 10 wk of age led to a significant increase in minumum overnight temperature compared to the control night, mean rise 0.25°C (95% CI, 0.12 to 0.38). In 35 IUGR infants the mean rise in temperature between immunization night and control night was 0.35°C (95% CI, 0.15 to 0.55). The increases in minimum temperature did not differ significantly between the normal and IUGR infants ( p = 0.11). Cortisol to creatinine ratios measured from overnight urine samples showed that 23 IUGR infants had consistently higher levels than 39 normal infants; control night medians 34 and 15 ( p = 0.01) and immunization night medians 56 and 26 ( p= 0.02), respectively. However, the percentage increase did not differ significantly between the IUGR infants and the normal infants. A smaller number of second immunizations were studied, but no significant differences were found.

Conclusion : These results suggest that although the impact of immunization is the same for IUGR and normal infants, because IUGR infants are less mature and at greater stress before immunization, the absolute levels that they experience after immunization are higher than those for normal infants.     

Delayed chemoreceptor responses in infants with apnoea.

AIMS: To test the hypothesis that apnoea of infancy (AOI) is due to a deficit in chemoreception. METHODS: Tests were performed on 112 infants: 43 healthy control infants, 28 infants with periodic breathing or central apnoea (PBCA), and 41 infants with obstructive apnoea (OA) on overnight polysomnography. Chemoreceptor responses to hypercapnia (4% and 6% CO2 in air) for 6-8 minutes and hyperoxia (100% O2) for 60 seconds were expressed in terms of response strength and reaction time. Age at birth (gestational week 37-41) and age at test (2-34 postnatal weeks) were comparable across groups (median, min-max value). A total of 70 CO2 and 71 O2 tests were analysed. RESULTS: The strongest and fastest CO2 responders were control infants: their median increase in ventilation was 291%/kPaCO2 and their reaction time 16 breaths. In infants with PBCA and OA, the increase in ventilation was 41% and 130%/kPaCO2, and reaction time 64 and 54 breaths, respectively. There was a significant negative correlation between CO2 response strength and response time. In response to hyperoxia there was a comparable decrease in ventilation in all infants (12-20%), but a significantly longer response time in infants with apnoea (20 v 12 breaths). There was no correlation between the response strength and response time to O2 and CO2. CONCLUSION: An inappropriate central control of respiration is an important mechanism in the pathogenesis of apnoea of infancy.     

Ampicillin use in infant fever: a systematic review.

OBJECTIVES: To estimate the prevalence of perinatal Listeria monocytogenes and enterococcal infections in outpatient febrile infants and to evaluate the need to treat with ampicillin. DATA SOURCES: Online bibliographies were searched for articles related to serious bacterial infection and fever in infants. Reference lists from selected and review articles were also examined. STUDY SELECTION: Studies that reported rates and types of bacterial infection in febrile outpatients younger than 3 months were included. Those performed outside North America, lacking results by age, or those that evaluated selected patient populations were excluded. DATA EXTRACTION: Two authors independently reviewed the selected articles for inclusion and abstracted the data. DATA SYNTHESIS: Fourteen studies, evaluating 5247 febrile outpatients, were included. The prevalences of L monocytogenes and enterococcal infections were 7.3 (binomial exact 95% confidence interval [CI], 3.5-13.3), 1.9 (95% CI, 0.6-4.4), and 5.6 (95% CI, 0.7-2.1) per 1000 febrile infants in the first, second, and third months of life, respectively. To cover 1 infant with serious bacterial infection caused by L monocytogenes and enterococcal infections, the numbers of febrile infants who would need ampicillin were estimated as 138 (95% CI, 76-288) in the first month, 527 (95% CI, 226-1621) in the second month, and 178 (95% CI, 50-1469) in the third month. Enterococcal infections occurred in all ages studied; there were no Listeria infections after 30 days of age. CONCLUSION: The empirical use of ampicillin to cover febrile infants for L monocytogenes and enterococcal infections is most justifiable in the first month of life.     

Test characteristics of the respiratory syncytial virus enzyme-linked immunoabsorbent assay in febrile infants < or = 60 days of age

The test characteristics of rapid tests for respiratory syncytial virus (RSV) in infants may differ from older children secondary to a lower likelihood of previous illness with RSV. Our main goal was to establish the test characteristics of the RSV Abbott Testpack (TP) enzyme-linked immunoabsorbent assay (EIA) in febrile infants < or = 60 days of age. Our secondary goal was to determine the likelihood of RSV given a particular clinical syndrome and a negative or positive EIA. A prospective sample of infants with a temperature > or = 38.0 degrees C was evaluated during 2 successive RSV seasons. Conventional tissue and shell vial viral cultures were utilized as the reference standard. The RSV Abbott Testpack EIA had a sensitivity of 75% (95% CI 60-90%), a specificity of 98% (95% CI 96-100%), a positive predictive value of 89% (95% CI 77-100%), a negative predictive value of 95% (95% CI 91-98%), a likelihood ratio for a positive test of 35.5 (95% CI 11.4-110.7), and a likelihood ratio for a negative test of 0.26 (95% CI 0.14-0.47). Even with a negative EIA, patients with lower and upper respiratory tract illness still had a 22.3% and 5.5% chance of harboring RSV, respectively. The RSV Abbott Testpack is a useful diagnostic tool in the detection of RSV in febrile infants but has limitations. During months typically associated with RSV disease, a positive RSV TP indicates a high likelihood of illness, but clinicians should be wary of false negatives.     

Overnight central and peripheral temperature changes in normal infants

Aim: To explore the relationship between central and peripheral temperature in normal infants after being put down to sleep. Methods: Overnight shin and rectal temperatures of 21 normal infants were continuously recorded at home for three nights at 2 wk, 6 wk, 3 mo and 5 mo of age. Parents documented the start and end of feed/nappy changes during the night. Results: An initial fall in rectal temperature was recorded on 149 out of 161 nights. This was linearly correlated with a rise in shin temperature for 106/149 (71%) nights (median R[Formula: See Text] = 0.95, lower quartile 0.92, upper quartile 0.97). It was not possible to rule out a change in thermal insulation over the shins as a confounding variable in this strong association. However, a similar inverse relationship was seen between shin and rectal temperature during 111 of 121 (92%) feed/nappy changes.

Conclusion: The fall in rectal temperature after being put down to sleep may be due to redistribution of heat rather than decreased production or heat loss. If causal, the development in early infancy of an inverse relationship between shin and rectal temperature may be important for cardiovascular homeostasis. Further sleep laboratory work is required to distinguish peripheral temperature changes on falling asleep from those associated with changes in thermal insulation.     

Orthogonal polarization spectral imaging (OPS): a novel method to measure the microcirculation in term and preterm infants transcutaneously

Little is known about the microvascular perfusion of the skin postnatally. Skin microvascular parameters can be assessed noninvasively with orthogonal polarization spectral imaging (OPS), a technique where, through the use of special optics, a virtual light source is created at a depth of 1 mm within the tissue. The light is absorbed by the Hb, yielding an image of the illuminated Hb-carrying structures in negative contrast. In nine term (weight 2100-4470 g) and 28 preterm infants (weight 550-2070 g; gestational age 24-33 wk) red blood cell velocity and vessel diameter and density were determined off-line with the Cap-Image program in vessels video-recorded by OPS near the axilla on d 1 and 5 of life. Blood pressure, heart rate, hematocrit, and body and incubator temperature were noted. Vessel diameter ranged from 6 to 24 microm, vessel density from 219 to 340 cm/cm(2) with no change between d 1 or 5 and no difference between term and preterm infants. Red blood cell velocity increased in preterm infants from d 1 [median 528 microm/s, 95% confidence interval (CI) 486-564 microm/s] to d 5 (median 570 microm/s; 95% CI 548-662 microm/s; p = 0.001) and correlated with the decrease in median hematocrit from 44% (CI 40%-60%) to 39% (CI 37%-43%) with r(2) = -0.37 with a 95% CI -0.59 to -0.11, p = 0.006. Hematocrit correlates with red blood cell velocity in the microvessels of the skin. The new technology can be used to assess quantitative changes in the microvessels and thus allows noninvasive assessment of tissue perfusion in term and preterm infants.     

Bed-sharing and the infant's thermal environment in the home setting.

AIMS: To study bed-sharing and cot-sleeping infants in the natural setting of their own home in order to identify differences in the thermal characteristics of the two sleep situations and their potential hazards. METHODS: Forty routine bed-sharing infants and 40 routine cot-sleeping infants aged 5-27 weeks were individually matched between groups for age and season. Overnight video and physiological data of bed-share infants and cot-sleeping infants were recorded in the infants' own homes including rectal, shin, and ambient temperature. RESULTS: The mean rectal temperature two hours after sleep onset for bed-share infants was 36.79 degrees C and for cot-sleeping infants, 36.75 degrees C (difference 0.05 degrees C, 95% CI -0.03 to 0.14). The rate of change thereafter was higher in the bed-share group than in the cot group (0.04 degrees C v 0.03 degrees C/h, difference 0.01, 0.00 to 0.02). Bed-share infants had a higher shin temperature at two hours (35.43 v 34.60 degrees C, difference 0.83, 0.18 to 1.49) and a higher rate of change (0.04 v -0.10 degrees C/h, difference 0.13, 0.08 to 0.19). Bed-sharing infants had more bedding. Face covering events were more common and bed-share infants woke and fed more frequently than cot infants (mean wake times/night: 4.6 v 2.5). CONCLUSIONS: Bed-share infants experience warmer thermal conditions than those of cot-sleeping infants, but are able to maintain adequate thermoregulation to maintain a normal core temperature.     

Model of normal prepubertal growth

Overheating may cause terminal apnoea and cot death. Rectal temperature and breathing patterns were examined in normal infants at home during the first 6 months of life. Twenty one infants had continuous overnight rectal temperature and breathing recordings for 429 nights (mean 20.4 nights, range 7-30) spaced over the first six months of life. Periods when breathing was 'regular' were directly marked on single night records. Sleep state was determined from respiratory variables. 'Regular' breathing was a reliable marker of 'quiet' sleep (specificity 93%). The duration of 'quiet' sleep increased from 6 to 22 minutes from two weeks to three months of age and then remained static, as did the proportion of sleep spent in the quiet phase (9% to 34%). Rectal temperature fell during 66% of quiet sleep and usually rose during rapid eye movement (REM) sleep. The drop in rectal temperature was maximal at the start of quiet sleep, whereas the maximum rise during REM sleep was reached after 10 to 15 minutes. Oscillations in rectal temperature are associated with changes in sleep and breathing state. The maturation of rectal temperature patterns during the first six months of life are closely related to a maturation of sleep state and breathing patterns.     

Delayed chemoreceptor responses in infants with apnoea

Aims: To test the hypothesis that apnoea of infancy (AOI) is due to a deficit in chemoreception. Methods: Tests were performed on 112 infants: 43 healthy control infants, 28 infants with periodic breathing or central apnoea (PBCA), and 41 infants with obstructive apnoea (OA) on overnight polysomnography. Chemoreceptor responses to hypercapnia (4% and 6% CO₂ in air) for 6–8 minutes and hyperoxia (100% O₂) for 60 seconds were expressed in terms of response strength and reaction time. Age at birth (gestational week 37–41) and age at test (2–34 postnatal weeks) were comparable across groups (median, min–max value). A total of 70 CO₂ and 71 O₂ tests were analysed. Results: The strongest and fastest CO₂ responders were control infants: their median increase in ventilation was 291%/kPaCO₂ and their reaction time 16 breaths. In infants with PBCA and OA, the increase in ventilation was 41% and 130%/kPaCO₂, and reaction time 64 and 54 breaths, respectively. There was a significant negative correlation between CO₂ response strength and response time. In response to hyperoxia there was a comparable decrease in ventilation in all infants (12–20%), but a significantly longer response time in infants with apnoea (20 v 12 breaths). There was no correlation between the response strength and response time to O₂ and CO₂. Conclusion: An inappropriate central control of respiration is an important mechanism in the pathogenesis of apnoea of infancy.     

Diagnostic testing for serious bacterial infections in infants aged 90 days or younger with bronchiolitis.

OBJECTIVES: To describe the different laboratory tests that are performed on young infants aged 90 days or younger with bronchiolitis and to identify historical and clinical predictors of infants on whom laboratory tests are performed. DESIGN: Cross-sectional study whereby information was obtained by retrospective review of medical records from November through March 1992 to 1995 of all infants with a clinical diagnosis of bronchiolitis. SETTING: Urban pediatric emergency department. PATIENTS: Two hundred eleven consecutive infants aged 90 days or younger (median age, 54 days) with 216 episodes of bronchiolitis. MAIN OUTCOME MEASURES: Historical and clinical data on each infant in addition to laboratory data that included a white blood cell count, urinalysis, and blood, urine, and cerebrospinal fluid cultures. RESULTS: Two or more laboratory tests (not including chest radiographs) were obtained in 48% of all infants and 78% of febrile infants. Of the 91 infants with a history of a temperature of 38.0 degrees C or more or temperature on presentation of 38.0 degrees C or more, white blood cell counts were obtained in 77%, blood cultures in 75%, urinalyses in 53%, urine cultures in 60%, and analyses-cultures of cerebrospinal fluid in 47%. Febrile infants were 10 times more likely to get at least 2 laboratory tests than afebrile infants (P<.01). All 6 studies were done in 42 (58%) of 72 febrile infants compared with 7 (16%) of 43 afebrile infants (P<.001). Multiple logistic regression analysis identified a history of a temperature of 38.0 degrees C or more or temperature on presentation of 38.0 degrees C or more (odds ratio [OR] 10.0; 95% confidence interval [CI], 4.8%-21.0%; P<.001), oxygen saturation less than 92% on presentation (OR, 4.7; 95% CI, 1.9%-12.1%; P<.01), and history of apnea (OR, 0.1; 95% CI, 0.02-0.35; P<.001) as significant clinical predictors of whether laboratory studies were obtained. History of preterm gestation, aged younger than 28 days, previous antibiotic use, and presence of otitis media were not associated with obtainment of laboratory studies. No cases of bacteremia, urinary tract infection, or meningitis were found among all infants with bronchiolitis who had blood, urine, and/or cerebrospinal fluid cultures. CONCLUSION: There is wide variability in the diagnostic testing of infants aged 90 days or younger with bronchiolitis. The risks of bacteremia, urinary tract infection, and meningitis in infants with bronchiolitis seems to be low. History or a documented temperature of 38.0 degrees C or more; oxygen saturation of less than 92%, and history of apnea were associated with laboratory testing for bacterial infections.     

Effect of positioning on the breathing pattern of preterm infants.

Respiration, as judged by gas exchange and pulmonary function, is improved in preterm infants kept in the prone rather than the supine position. The influence of position on the breathing pattern as documented by the pneumogram was studied in 14 stable preterm infants with recent clinical apnoea. Ten of the infants had oximetry and nasal flow studies simultaneously with the impedance pneumogram. Each infant had consecutive nocturnal pneumograms, one in the prone, one in the supine position. The infants were kept for more than six hours in the assigned position. A significant increase in apnoea density and in periodic breathing was found in the supine v the prone position (mean (SE) 4.5 (0.7)% v 2.5 (0.5)%, and 13.6 (3.2)% v 7.7 (2.2)%, respectively). There was no positional difference in the incidence of bradycardia and prolonged apnoea. The examination of obstructive apnoea, mixed apnoea, and cyanotic spells did not reveal a consistent disparity between the two positions. These findings indicate an increase in central apnoea in preterm infants kept predominantly in the supine position. Possible relations of positional changes to lung mechanics are discussed. When evaluating pneumograms, attention must be given to the position in which they were performed.     

Otitis media in infants aged 0-8 weeks: frequency of associated serious bacterial disease.

OBJECTIVE: To determine the frequency of serious bacterial infection in well appearing infants aged 0-8 weeks with isolated otitis media (OM). METHODS: Infants with confirmed OM underwent tympanocentesis with middle ear fluid (MEF) culture and complete sepsis evaluation. Enrolled infants were admitted to the hospital for parenteral antibiotics until blood, urine, and CSF cultures were negative for 48 hours. RESULTS: Forty non-toxic appearing infants were enrolled between January 1994 and April 1995, of whom 15 (38%) had a documented rectal temperature > or =38 degrees C. Bacterial pathogens were isolated from MEF cultures in 25 (62.5%) infants. All afebrile infants had negative blood, urine, and cerebrospinal fluid cultures (upper limit (UL) 95% CI 0.11). Only two febrile infants had positive cultures from sites other than the MEF (UL 95% CI 0.36). CONCLUSION: In our study population, previously healthy, non-toxic appearing afebrile infants aged 2-8 weeks and having isolated OM infrequently have an associated serious bacterial infection, suggesting that outpatient treatment with oral antibiotics and close follow-up may be an option. Further studies with large numbers of infants are necessary to confirm this conclusion.     

Effects of nasal continuous positive airway pressure on apnoea index and sleep in infants

Objectives: We examined the effectiveness of nasal continuous positive airway pressure (CPAP) for treatment of sleep apnoea in infants.
Methodology: We studied five infants who all had significant central and mixed apnoea and severe sleep fragmentation. Polysomnographic recordings were performed on 2 consecutive nights in these infants. One night was used as a control study and during the second night nasal CPAP was applied throughout the night
Results: Nasal CPAP significantly reduced apnoea in each infant, with the apnoea index (apnoeas/h) decreasing from 65.6± 14.6 during the control study to 10.5± 14.6 during CPAP in non-rapid eye movement (non-REM) sleep, and from 106± 13.9 during the control study to 26.6± 13.9 during CPAP in REM sleep. Nasal CPAP also improved the sleep fragmentation markedly; REM sleep increased from 14.2± 1.2% of sleep during the control study to 27.1 ± 1.2% of sleep during CPAP.
Conclusions: We conclude that nasal CPAP is an effective treatment for infantile apnoea. Sleep apnoea in these infants is associated with profound sleep fragmentation, which is reversed by nasal CPAP.     

Congenital Anomalies in Singapore

Abstract A 3-year study (Jan. 1986-Dec. 1988) in the Kandang Kerbau Hospital revealed 678 infants with birth defects in 44,842 livebirths, (15.13 per 1,000 live births, 95% confidence intervals, CI 14.0–16.2). There were 161 cases with musculoskeletal abnormalities (3.5 per 1,000, 95% CI 3.06-4.19), 111 gastrointestinal system malformations (2.47 per 1,000, 95% CI 2.04-2.58), 88 chromosomal abnormalities (1.96 per 1,000, 95% CI 1.57-2.42), 78 cardiovascular system abnormalities (1.74 per 1,000, 95% CI 1.38-2.17), 73 urogenital system defects (1.63 per 1,000, 95% CI 1.28-2.05), and 52 central nervous system defects (1.16 per 1,000, 95% CI 0.87-1.52). The prevalence of cleft lip, cleft palate, and cleft lip/palate was 1.72 per 1,000, and Down's Syndrome 1 in 700. At review, six weeks later, the false positive rate was 4% in the infants with defects, and in the group of 709 normal controls (matched by race, maternal age, ward class and time/date of birth), the false negative rate was 0.84%. The strongest risk factors were a family history of birth defects (odds ratio, OR 3.3, 95% CI 1.8-6.4), and previous abnormal sibling(s) (OR 2.4, 95% CI 1.1–5.3). Other risk factors included drug intake during pregnancy (OR 1.2, 95% CI 0.8-2.0), becoming significant with ingestion during the first trimester (OR 1.4, 95% CI 1.1-1.8). Traditional medicine (mainly Chinese herbs during pregnancy) had a slightly higher risk (OR 1.4, 95% CI 1.0–2.0). The National University Hospital keeps a register of birth defects; trained nurses interview all mothers using a set questionnaire. Evaluation of 11,460 livebirths over a 3-year period (1991–1993) revealed 472 cases (41.19 per 1,000 livebirths, 95% CI 37.48-44.90) with 171 musculoskeletal defects (14.92 per 1,000 livebirths, 95% CI 12.69-17.16), 105 cardiovascular defects (9.16 per 1,000, 95% CI 7.41-10.91), 64 urogenital defects (5.58 per 1,000, 95% CI 4.22-6.95), 30 gastrointestinal defects (2.62 per 1000, 95% CI 1.68-3.55), 35 mixed system defects (3.06 per 1,000, 95% CI 2.04-4.07), and 18 chromosomal abnormalities (1.57 per 1,000, 95% CI 0.85-2.30). The prevalence of cleft lip/cleft lip and palate was 1.48 per 1,000. This higher prevalence could be due to the present practice of routine screening of every infant on the first day of life, together with a careful assessment for musculoskeletal defects, especially congenital dislocation of the hips.     

Apneas en lactantes con bronquiolitis: incidencia y factores de riesgo para un modelo de predicción

Introduction

The presence of apnoea in acute bronchiolitis (AB) varies between 1.2% and 28.8%, depending on the series, and is one of its most fearsome complications. The aim of this study is to determine the incidence of apnoea in hospitalised patients diagnosed with AB, and to define their associated risk factors in order to construct a prediction model.

The efficacy of heparinization in prolonging patency of arterial and central venous catheters in children: a randomized double-blind trial

This study evaluates the efficacy of heparinization in prolonging patency of arterial and central venous catheters in children. A randomized double-blind trial in a tertiary 10-bed pediatric intensive care unit was used to evaluate 300 children (age older than 4 weeks, younger than 18 years). Trial medication consisted of either NaCl 0.9% infusion or NaCl 0.9% infusion to which 1 IU of heparin per milliliter was added. The number of nonpatent arterial and central venous catheters and the duration of stay of patent arterial and central venous catheters were measured. There was a significant risk increase for nonpatency in the nonheparinized arterial catheters (relative risk [RR]: 3.54; 95% confidence interval [CI]: 1.01-12.42). No significant risk increase for nonpatency could be demonstrated for the nonheparinized central venous catheters (RR: 7.63; 95% CI: 0.40-145). The median duration of stay of the patent arterial and central venous catheters was similar for both treatment groups. These results indicate that the use of normal saline in arterial catheters is associated with an increased frequency of catheter nonpatency as compared with heparinized saline.     

THE EFFICACY OF HEPARINIZATION IN PROLONGING PATENCY OF ARTERIAL AND CENTRAL VENOUS CATHETERS IN CHILDREN: A Randomized Double-Blind Trial

This study evaluates the efficacy of heparinization in prolonging patency of arterial and central venous catheters in children. A randomized double-blind trial in a tertiary 10-bed pediatric intensive care unit was used to evaluate 300 children (age older than 4 weeks, younger than 18 years). Trial medication consisted of either NaCl 0.9% infusion or NaCl 0.9% infusion to which 1 IU of heparin per milliliter was added. The number of nonpatent arterial and central venous catheters and the duration of stay of patent arterial and central venous catheters were measured. There was a significant risk increase for nonpatency in the nonheparinized arterial catheters (relative risk [RR]: 3.54; 95% confidence interval [CI]: 1.01-12.42). No significant risk increase for nonpatency could be demonstrated for the nonheparinized central venous catheters (RR: 7.63; 95% CI: 0.40-145). The median duration of stay of the patent arterial and central venous catheters was similar for both treatment groups. These results indicate that the use of normal saline in arterial catheters is associated with an increased frequency of catheter nonpatency as compared with heparinized saline.     

RELATIONSHIP BETWEEN APNOEA AND BRADYCARDIA IN PRETERM INFANTS

Abstract. Vyas, H., Milner, A. D. and Hopkin. I. E. (Department of Child Health, Department of Neonatal Medicine and Surgery, City Hospital, Nottingham, England). Relationship between apnoea and bradycardia in preterm infants. Acta Paediatr Scand, 70: 785, 1981.-Nine studies were carried out on seven babies who were having repeated episodes of bradycardias without any clinically obvious apnoea. Their mean gestational age was 31.7 weeks (range 29 to 36 weeks) and the mean birth weight was 1.56 kg (range 1.08 kg to 2.16 kg). Investigations were carried out in a total body plethysmograph. Face mask with a pneumotachograph attached to it measured flow. Tidal volume was obtained by integrating these signals. An oesophageal balloon measured intrathoracic pressure changes and the heart rate was measured from ECG chest electrodes. A total of 172 episodes of apnoea were observed. In 50 % of these apnoeas, the airway was closed as determined by the absence of cardiac artefact on the flow signals. Apnoea was associated with bradycardia in just over 25 % of all apnoea. It tended to occur early (11 to 14 sec). Whether the apnoea was central or obstructive had no effect on the pattern provided the baby did not make any inspiratory efforts. Inspiration against a closed airway produced bradycardia in over 50 % of obstructive apnoea, the heart rate falling precipitously within 1 to 2 sec. These findings indicate that often bradycardias occur too early-in apnoea to be due to central hypoxia and must be due to a peripheral mechanism.     

Prophylactic use of acetaminophen in children vaccinated with diphtheria-tetanus-pertussis

Background  The present randomized non-blind trial was conducted to clarify the effect of analgesics on febrile responses of booster diphtheria-tetanus-whole cell pertussis (DTP) vaccine in 15–20 months old infants. Methods  A total of 270 healthy infants were randomized to receive acetaminophen (10 mg/kg) along with DTP vaccine (group 1), 2 hours after vaccination (group 2), and after the appearance of febrile reactions or irritability following vaccination (group 3, control). In addition to study medication, if the axillary temperature was higher than 38°C or if the infant seemed to be irritable, the parents were told to give acetaminophen (10 mg/kg) and record on a diary card. Vaccinees were monitored for local and systemic reactions. Results  The incidences of local swelling, pain and erythema were not significantly different among the 3 groups. No difference was observed in the incidence of systemic reactions including febrile responses, irritability, anorexia, and vomiting among the 3 groups during the 7 days after vaccination. Of the infants, 45.1%, 46.7% and 51.9% manifested fever (axillary temperature ≥38°C) within 24 hours after the vaccination in groups 1, 2 and 3, respectively (P>0.05). The second dose of acetaminophen was less in the control group than in the prophylactic groups (P=0.009). Conclusions  Administration of acetaminophen along with DTP vaccine or 2 hours after vaccination does not affect the occurrence of febrile responses following booster vaccination. Unnecessary use of analgesics should be prevented.     

Bronchial responsiveness and lung function in infants with lower respiratory tract illness over the first six months of life.

The aim of this study was to determine whether increased bronchial responsiveness to histamine is associated with lower respiratory tract illness (one or more episodes of wheeze or cough, or both) in infancy. Fifty four normal newborn infants who had at least one atopic parent were recruited. At a median age of 6.5 months, 45 infants, 23 with a history of lower respiratory tract illness, and 22 without, underwent pulmonary function testing during a symptom free period. The maximum flow at functional residual capacity (VmaxFRC) was calculated from partial forced expiratory flow volume curves using the squeeze technique. Bronchial responsiveness to increasing doses of histamine was assessed by determining the provoking concentration which caused a 30% decrease in VmaxFRC (PC30). The length adjusted VmaxFRC was lower for symptomatic infants before the challenge (median 125 ml/s; 95% confidence intervals (CI) 85 to 164 ml/s) compared with control infants (median 215 ml/s; 95% CI 159 to 298 ml/s). There was no significant difference in PC30 between symptomatic infants (median 10.3 g/l; 95% CI 2.8 to 23.8 g/l) and control infants (median 16.5 g/l; 95% CI 2.4 to 27.9 g/l). Bronchial responsiveness to histamine can be shown in most infants early in life and is independent of lower respiratory tract symptoms including wheezing.