Adverse circulatory effects of passive smoking during infancy: surprisingly strong, manifest early, easily avoided.

AIM: To compare blood pressure reactions (BPR) of infants to mild stress for evidence of adverse cardiovascular effects of passive exposure to tobacco smoke during pregnancy and early infancy. METHODS: An observational field study conducted in Crete. We compared 4- to 6-month olds of lifelong nonsmokers minimally (controls, n = 9) or frequently exposed to tobacco smoke (passive smokers; n = 10) with those born to habitual smokers (n = 6). Smoke exposure was verified biochemically (urine cotinine each trimester and at study). We recorded beat-to-beat blood pressure (BP) during brief repositioning manoeuvres performed during a daytime nap and analysed BPR (% change in BP during head-up tilt) for associations with maternal and infant cotinine. RESULTS: We observed a 20-fold difference between BPR of infants of controls versus passive smokers - exceptional given number of infants (α error/confidence level <10% i.e. power >90%). The BPR declined linearly as the infant's (but not mother's) cotinine level rose (p = 0.04), indicating abnormal BPR was caused mainly by postnatal smoke exposure. Infants of active smokers differed from those of passive smokers. CONCLUSION: Cardiovascular effects of passive smoking by a newborn infant manifest early on and are exceptionally strong. They can be largely avoided by keeping the home smoke rigorously free.

The effect of growth hormone on sleep-related cardio-respiratory control in Prader-Willi syndrome.

AIM: To evaluate the effects of growth hormone (GH) treatment on control of breathing, heart rate and blood pressure during sleep in Prader-Willi Syndrome (PWS). STUDY DESIGN: In a prospective clinical case series study, sixteen consecutive PWS patients (median age 16 months at enrolment) were followed-up 6 months (2-32 months) after commencing GH treatment. We compared heart rate (HR), Pulse Transit Time (PTT; an index of blood pressure, BP) and ventilatory responses to standard chemostimuli (4% CO(2) and 100% O(2)) during quiet sleep prior to and after commencing GH treatment. RESULTS: Growth hormone treatment increased arterial oxygenation during sleep but did not significantly improve breathing stability (apnoea-hypopnoea index remained unchanged). GH treatment did not alter ventilatory, HR and PTT chemoreceptor-mediated responsiveness (p = 0.23-0.97) but did significantly improve the coupling between and HR and PTT, indicating that HR and BP rose (or fell) in parallel after but not before GH therapy (p = 0.01). CONCLUSION: Growth hormone treatment improves arterial oxygenation and cardiovascular function during sleep; these changes are not owing to improved (stronger) chemoreflex-mediated autonomic drive.

Mode of delivery modulates physiological and behavioral responses to neonatal pain.

OBJECTIVE: To study whether the mode of delivery alters pain expression. STUDY DESIGN: Full-term infants born by vaginal delivery or elective caesarean section were observed following high- and low-intensity pain stimuli, with recording of electrocardiogram, facial expression and vocalization. RESULT: Graded physiological and behavioral responses occurred, with greater responses to higher than lower intensity pain stimuli. Elevation in heart rate following both stimuli increased with time after vaginal delivery. Infants delivered by elective caesarean section showed stronger facial expressions and briefer time in vocalizations response to both interventions. CONCLUSION: Diminished responses following vaginal delivery suggest that physiological events associated with a normal delivery reduce the physiologic and sympathoadrenal activation by nociceptive mechanisms. Pain and stress reactivity appear to be inhibited during fetal life and sensory inputs during vaginal delivery may reverse this inhibition. To minimize neonatal pain, we recommend that postnatal invasive procedures to be performed shortly after vaginal birth.

Cardiorespiratory development in extremely preterm infants: vulnerability to infection and persistence of events beyond term-equivalent age.

OBJECTIVE: Apnoea, bradycardia and hypoxemia occur frequently in extremely preterm infants, yet there is little longitudinal data describing cardiorespiratory development in these infants. This prospective study characterized early age-dependent changes in cardiorespiratory function and determined how activity is affected by factors such as underlying disease, postnatal insults and therapeutic interventions. PATIENTS AND METHODS: Thirty-three infants born between 23 and 28 weeks gestational age (GA) were monitored weekly from birth to beyond term-equivalent age (i.e. 25-45 weeks postconceptional age, PCA). Baseline cardiorespiratory activity as well as apnoea/hypopnoea, bradycardia and hypoxemia events were examined using impedance pneumography, electrocardiography (ECG) and pulse oximetry, respectively. RESULTS: Three hundred thirty-eight cardiorespiratory recordings lasting 3236 h were analysed. While the respiratory rate (RR) did not change during the early postnatal period, heart rate (HR) decreased and O2 saturation improved. There were 5973 total cardiorespiratory events, and their incidence decreased with advancing age. However, they still occurred frequently at term-equivalent age and after hospital discharge (mean PCA at discharge=38.3+/-0.5 weeks). Moreover, infection significantly increased apnoea/hypopnoea and hypoxemia incidence. CONCLUSION: The persistence of cardiorespiratory events beyond term-equivalent age as well as the marked impact of infection on cardiorespiratory function indicate that close surveillance after hospitalization is of crucial importance in extremely preterm infants.

Implementation of surfactant treatment during continuous positive airway pressure.

OBJECTIVE: To study the effects of implementing a method for surfactant administration by transient intubation, INSURE (i.e. INtubation SURfactant Extubation) during nasal continuous positive airway pressure (nCPAP) for moderately preterm infants with respiratory distress syndrome (RDS). STUDY DESIGN: A descriptive, retrospective, bi-center study in Stockholm, Sweden, comparing mechanical ventilation (MV) rates, surfactant use, treatment response and outcome of all inborn infants with gestational age 27 to 34 weeks and RDS, (n=420), during the 5-year periods before and after the introduction of the INSURE-strategy at one of the centers (Karolinska Huddinge) in 1998. The other center (Karolinska Solna) continued conventional surfactant therapy in conjunction with MV throughout the study. RESULTS: Implementation of INSURE at Karolinska Huddinge reduced the number of infants requiring MV by 50% (P<0.01), resulted in earlier surfactant administration and increased overall surfactant use. INSURE-treatment improved oxygenation and the treatment response was sustained over time with only 17% of the infants requiring >1 dose of surfactant. At Karolinska Solna, the MV rates were unaltered between the first and second 5-year period. CONCLUSION: Implementing a strategy of surfactant administration by transient intubation during nCPAP reduces the need for MV without adverse effects on outcome and may be an option to more effectively treat RDS, particularly in a care setting where transfer is necessary to provide MV.

Eosinophil activation in preterm infants with lung disease.

AIM: We investigated the role of eosinophils in the pathogenesis of bronchopulmonary dysplasia (BPD) in preterm infants. METHODS: Fifteen preterm infants with BPD were compared to 13 preterms with respiratory distress syndrome (RDS) and to 16 healthy preterms. We assessed total eosinophil and neutrophil counts in venous blood samples and the levels of the eosinophilic activity markers eosinophilic cationic protein (ECP) and the cellular surface antigen (CD9). RESULTS: The eosinophil count was greater in BPD compared with RDS and healthy infants (1414 vs. 797 and 471 cells per microlitre, respectively, p = 0.03). ECP levels were elevated (34 vs. 12.8 and 9.8 microg/L, respectively, p = 0.002) and CD9 levels reduced (75 vs. 94 and 86 mean fluorescence intensity units, respectively, p = 0.01) in BPD compared with RDS and healthy infants, suggesting eosinophilic activation in BPD. These findings were not solely explained by differences between gestational age or birth weight of the different groups. ECP levels were positively correlated with the duration of oxygen supplementation in the BPD group. The eosinophil count fell promptly after steroid treatment was commenced in the BPD group. CONCLUSION: The findings suggest that BPD is linked to eosinophil activation, which might contribute to the pathogenesis.

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.

Stability of longitudinal motor development in very low birthweight infants from 5 months to 5.5 years.

AIM: The motor performance of 165 very low birthweight (VLBW) infants was assessed prospectively at 5, 10, 18 mo and 5.5 y. The aim of the study was to evaluate longitudinal stability of motor development and its association with birthweight (BW), gestational age at birth, intraventricular haemorrhage (IVH), periventricular leucomalacia (PVL) and retinopathy of prematurity (ROP). Furthermore, at 5.5 y the motor behaviour of the VLBW population was compared with that of 124 children born at term. METHODS: The results of each examination were ranked into four levels and the stability of motor development was evaluated on the basis of this ranking. At 5.5 y, VLBW children and controls were compared according to percentiles in the Movement ABC. RESULTS: Fifty-three percent of the VLBW infants displayed a stable motor development. Only PVL and BW contributed significantly to the variability in their motor performance. Forty-seven percent of the infants exhibited an unstable motor development with no association to risk factors. In the entire group only IVH and severe ROP were related to poor motor performance. The majority of the VLBW children performed within the normal range at 5.5 y but their performances were inferior to those of control children. CONCLUSION: VLBW infants with poor early motor performance and/or severe IVH/PVL and ROP should be recruited into individualized follow-up programmes, whereas regular ongoing monitoring by follow-up may be sufficient for those with normal early motor performance and normal ultrasound findings.

Cognitive development at 5.5 years of children with chronic lung disease of prematurity.

BACKGROUND: Preterm infants with chronic lung disease (CLD) had impaired cognitive development and poorer eye-hand coordination at 10 months of age. AIMS: To study whether this effect of CLD persisted until school age and whether the severity of CLD affected outcome. METHOD: Cognition and visual-motor skills were examined (Wechsler preschool and primary scale of intelligence, and tests from the Nepsy scale) in 60 very preterm children, without intraventricular haemorrhage or periventricular leucomalacia, at 5.5 years of age. Thirty two children suffered from CLD and 28 were controls. RESULTS: The groups did not differ significantly in cognitive outcome. Children with CLD and controls attained a full scale intelligence quotient (IQ) of 94.4 and 99.1, a verbal IQ of 99.6 and 101.5, and a performance IQ of 90.9 and 96.7 respectively. Similarly, no difference was found in tests of eye-hand control. However, the children with the most severe form of CLD had significantly lower performance (84.8) and full scale(87.6) IQs and worse visual-motor performance than the controls. CLD grade III, together with the need for glasses or lenses, had a significant impact on the explained variance. CONCLUSIONS: At school age, children born very preterm and who experienced severe CLD had deficits in cognition, visual-motor perception, and performance. The findings suggest a need to consider intervention programmes for such infants.

Increased inspiratory effort in infants with a history of apparent life-threatening event.

UNLABELLED: The objective of this study was to compare the results of polysomnography between infants with a history of apparent life-threatening event (ALTE) and controls. In this case-control study, 40 full-term ALTE infants, aged 2-36 wk at the time of the event, were compared with 40 age- and sex-matched randomly selected controls. SaO2, tcpO2, tcpCO2, heart rate (HR), vector of rib cage and abdominal respiratory movements (phase angle, as an index of inspiratory effort) were recorded during natural nocturnal active and quiet sleep (AS, QS). SaO2, tcpO2, tcpCO2 were similar in ALTE and controls in both sleep states. Phase angle was increased in ALTE infants in both AS (59+/-46 vs 26+/-17 degrees) and QS (53+/-46 vs 18+/-14, p < 0.001). Eleven ALTE infants (27.5%) experienced SaO2 < 90%, with a mean decrease in SaO2 to 86+/-1.6% (mean +/- SD), compared with 10% for controls (p=0.003). In eight ALTE infants, SaO2 values <90% were linked to thoracoabdominal asynchrony. SaO2 < 90% in conjunction with HR <100 bpm were detected in three ALTE infants and one control. Periodic breathing was observed in 45% of ALTE infants and 40% of controls. CONCLUSION: The mean values of oxygen saturation, tcpO2 and carbon dioxide levels in ALTE infants are comparable with those of healthy controls but the ALTE infants exhibit more hypoxaemic episodes and increased inspiratory effort during sleep.

Abnormal heart rate response to hypercapnia in boys with an apparent life-threatening event.

AIM: To determine instantaneous cardiac variability responses to increased carbon dioxide (CO2) during quiet sleep in infants who may be at risk for the Sudden Infant Death syndrome (SIDS). METHODS: The cardiac rate variability before, during and after a CO2 challenge was examined in 41 infants who had experienced an apparent life-threatening event (ALTE) and 41 gender- and age-matched control infants. RESULTS: The ALTE infants responded to CO2 breathing with a significant increase in R-R intervals, i.e. decreases in heart rate, compared to the controls (45.1% increase in R-R intervals vs. 41.4%; p = 0.005). The differences between ALTE infants and controls depended primarily on the boys' responses. CONCLUSION: ALTE infants, particularly ALTE boys, have an autonomic dysfunction-lower sympathetic stimulation and/or inhibited vagal withdrawal when stressed with CO2. The outcome might provide clues to the mechanisms underlying the cardiovascular processes contributing to the terminal event in SIDS.

Breathing patterns, oxygen and carbon dioxide levels in sleeping healthy infants during the first nine months after birth.

UNLABELLED: Data on arterial oxygen saturation (SaO2), transcutaneous PO2, pCO2 (tcpO2, tcpCO2) and breathing patterns in sleeping healthy term infants were obtained during the first 9 mo after birth. Forty-four healthy infants, mean GA at birth 40 +/- 1.0 wk, mean BW 3520 +/- 562 g were examined between 2 wk and 9 mo postnatally in a cross-sectional study. SaO2, tcpO2, tcpCO2, heart rate (HR), rib cage and abdominal respiratory movements were recorded during natural nocturnal sleep, stratified for sleep states (active sleep (AS), indeterminate sleep (IS), quiet sleep (QS)). The data on AS and IS were pooled as in previous studies. The variables were analysed with respect to age. SaO2 in AS + IS and QS was 96.1 +/- 1.3%, 96.6 +/- 1.4%, respectively. TcpO2 in AS + IS was 10.6 +/- 1.1 kPa and 10.7 +/- 1.3 kPa in QS, while tcpCO2 in AS + IS was 5.4 +/- 0.3 kPa and 5.4 +/- 0.4 kPa in QS. Neither SaO2 nor tcpO2 was influenced by age. TcpCO2 decreased significantly postnatally. Five infants (11.3%) experienced episodes of hypoxaemia with a mean decrease in SaO2 to 86 +/- 1.5%. In four infants these hypoxaemic episodes were linked to upper airway obstructions. Episodes of SaO2 < 90% in conjunction with a decrease in HR to < 100 bpm were detected in one infant only. Periodic breathing (PB) was observed in 38.6% of infants. CONCLUSION: Oxygenation and carbon dioxide levels in sleeping healthy term infants were comparable to those reported in older children. Hypoxaemic episodes, if present, are associated with upper airway obstruction. PB, often assumed to be a pathological feature, is a normal breathing pattern in this age group.

Heart rate variability in infants with apparent life-threatening events.

UNLABELLED: Heart rate variability (HRV) is often used as an index of sympatho-vagal balance. A decreased HRV has been observed in patients with central hypoventilation and in infants who have later succumbed to sudden infant death syndrome (SIDS). The aim of the present study was to investigate whether HRV is altered in infants with apparent life-threatening events (ALTE), a group with an increased risk of SIDS. Fifty infants with ALTE were compared with 50 age- and sex-matched controls. ECG was recorded overnight in all infants. Two sequences of RR intervals free of artefacts were selected from each sleep state and spectral analysis of RR variability was performed. The mean and SD of RR and the low (LFPow) and high (HFPow) frequency power were analysed. In active sleep (AS) the LF/HF ratio was lower in ALTE infants, but no differences were seen in either the LFPow or the HFPow. In quiet sleep (QS), however, ALTE infants had higher SD-RR (p = 0.006), greater HFPow (p = 0.02) and VLFPow (very low frequency power, p = 0.02) than the control infants. The same results were seen when the two sleep states were combined for analysis, ALTE infants had higher SD-RR (p = 0.004), HFPow (p = 0.006) and VLFPow (p = 0.04). CONCLUSION: The different HRV pattern in ALTE infants compared to healthy controls suggests an altered autonomic control.

[Fiberoptic endoscopy confirms the cause of upper respiratory obstruction in small children. The most common causes to referrals are sleep apnea syndrome and inspiratory stridor]. / Fiberskopi fastställer orsak till höga andningshinder hos små barn. Vanligaste remissorsakerna sömnapnésyndrom och inspiratorisk stridor.

Guidelines for the clinical investigation of young children with stridor and sleep apnea are presented. Clinical examination and flexible videolaryngoscopy performed in local anaesthesia are the most important diagnostic tools for this group of children. If the impairment is severe or an objective evaluation is needed the child should also undergo nocturnal polygraphic recording and lung function tests. Out of 43 children examined with flexible videolaryngoscopy 21 had positive findings, laryngomalacia being the most common diagnosis. Flexible videolaryngoscopy is a good complement to laryngoscopy under general anaesthesia. It can be performed as early as in the neonatal period.

Early motor and mental development in very preterm infants with chronic lung disease.

BACKGROUND: The increased incidence of neurological deviations in preterm infants with chronic lung disease (CLD) has been linked to severe brain haemorrhage (intraventricular haemorrhage (IVH)) and periventricular leucomalacia (PVL) rather than to CLD per se. AIM: To evaluate whether CLD without concomitant brain lesions constitutes a risk factor for adverse developmental outcome. METHOD: Forty three very low birthweight infants with CLD, but without IVH or PVL, and 43 very low birthweight infants without CLD, IVH, or PVL were evaluated at 5 and 10 months of corrected age using the movement assessment of infants (MAI) scale. The Griffiths' developmental test was carried out at 10 months of age. RESULTS: The overall motor assessments (MAI) in infants with CLD and controls were not significantly different. However, differences were observed in the execution of volitional movements (MAI), the total sum, hand and eye coordination, and perception and intelligence (measured by the performance scale of the Griffiths' test). CONCLUSIONS: CLD has a deleterious effect on the control of hand and eye coordination and on perception and intelligence. These results thus re-emphasise the necessity for careful neurodevelopmental follow up of infants with CLD whether or not they suffered IVH or PVL.

Periventricular leucomalacia and preterm birth have different detrimental effects on postural adjustments.

Postural adjustments during sitting on a moveable platform were assessed by means of multiple surface EMGs of neck, trunk and leg muscles and kinematics in three groups of children, aged 1 1/2-4 1/2 years. The first group consisted of 13 preterm children (born at a gestational age of 25-34 weeks), whose neonatal ultrasounds had shown distinct lesions of the periventicular white matter (PWM). The second group was the preterm control group, consisting of 13 preterm children with normal neonatal brain scans, matched to the PWM group with respect to gestational age at birth, birth weight, sex and age of postural assessment. The third group was formed by 13 healthy children born at term and matched to the PWM group with respect to sex and age at examination. In addition to the postural assessment an age-specific neurological examination was carried out. Three of the children of the PWM group developed a cerebral palsy syndrome, nine showed minor neurological dysfunction and one child was neurologically normal. In the preterm control group one child showed minor neurological dysfunction, while the remaining 12 children of this group and all children of the full-term group were neurologically normal. The postural assessment revealed that preterm birth was associated with two types of postural dysfunction. One dysfunction was related to the presence of a PWM lesion and consisted of a limited repertoire of response variation. The other dysfunction was not related to the presence of a PWM lesion, but to preterm birth itself. It consisted of a change in the ability to modulate the postural responses. Preterm children showed a higher sensitivity to platform velocity than full-term children, and they lacked the capacity to modulate EMG amplitude with respect to initial sitting position.

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.

Neonatal care of very-low-birthweight infants in special-care units and neonatal intensive-care units in Stockholm. Early nasal continuous positive airway pressure versus mechanical ventilation: gains and losses.

Very-low-birthweight (VLBW) infants are usually intubated at birth and mechanically ventilated at neonatal intensive-care units (NICUs). The objectives of this study were to evaluate the use of early nasal continuous positive airway pressure (NCPAP) in a regional cohort and to determine to what extent VLBW infants need transfer to a regional NICU from special-care units (SCUs) that primarily use early NCPAP for respiratory care. We compared the outcome for infants at SCUs and NICUs in Stockholm County, Sweden, from 1988 to 1993. All infants with birthweights of less than 1501 g were included in this study (n = 687). Fifty-nine per cent of the infants (400/687) were supported using only supplemental oxygen or NCPAP. Of these, 170 (25%) received only supplemental oxygen and 230 (34%) were supported only by NCPAP. A total of 350 (51%) infants received early NCPAP. Of these infants, 120 (34%) later required mechanical ventilation. Only 167 (24%) infants received mechanical ventilation from the beginning Failure of NCPAP was significantly associated with the presence of respiratory distress syndrome. A total of 161/412 (39%) infants were transferred from SCUs to NICUs. Of infants < or = 26 weeks' gestation and infants > 26 weeks, 71% and 34% were transferred, respectively. Total mortality was 16%. The mortality for transfers was 20% compared to an overall mortality in SCU and NICU infants of 9% and 15%, respectively. The overall incidence of intraventricular haemorrhage (IVH), grade III-IV was 8%, periventricular leucomalacia (PVL) grade I-IV was 7%, retinopathy of prematurity (ROP) requiring cryotherapy was 4.3% and chronic lung disease (CLD) was 14%. There were significant differences in the incidence IVH, PVL, CLD and ROP between SCU and NICU infants in matched gestational age groups. In conclusion, infants with a gestational age of 27 weeks or more may often be adequately cared for at SCUs without mechanical ventilation by using early NCPAP. However, infants with a gestational age of 26 weeks or less should be transferred to tertiary-care centres preferably before birth, because they will often require mechanical ventilation.

The Stockholm Neonatal Project: neonatal mortality and morbidity at the Children's Centre, Karolinska Hospital.

Two hundred and ninety-one very-low-birth-weight (VLBW) infants were studied prospectively during the period of 1988-1993. All inborn VLBW infants and most of the VLBW infants born in Greater Stockholm and requiring neonatal intensive care were included in this study. The overall mortality was 17.5% and the mortality in the group with the lowest gestational age at birth, i.e. 23-24 weeks, was 25%. The mortality for boys was higher than for the girls. The mode of delivery, i.e. vaginal versus caesarean section and multiple birth, did not seem to affect the mortality rate. Respiratory insufficiency and/or cerebral complications were the most common cause of neonatal death. Patent ductus arteriosus was found in 35% of the infants, of whom 43% needed surgical ligation. One-third of infants with retinopathy of prematurity (30/92) required cryotherapy.

Diagnosis of intracranial lesions in very-low-birthweight infants by ultrasound: incidence and association with potential risk factors.

This study was designed to determine the frequencies of germinal matrix and ventricular haemorrhages as well as lesions in the white matter diagnosed by ultrasonography. In subsequent studies the effects of perinatal brain lesions on the cognitive and motor development of preterm children will be presented. Lesions of the white matter are probably more damaging than intraventricular and subependymal bleeds. Therefore, a modified classification of the lesions was used, clearly separating bleeds from white matter pathology. The study includes 291 infants with a body weight of < or = 1500 g consecutively admitted to the neonatal intensive-case unit at Karolinska Hospital from 1988 to 1993. Fifty-four (18.9%) died before 6 months. Two hundred and sixty-three infants were examined using ultrasound. Pathology due to bleeding was classified into three grades (B1-3) similar to Papile's first three grades. Pathology in periventricular white matter was classified into four groups (W1-4): W1 = subtle and We = distinctive white matter echodensities; W3 = cyst formation; W4 = large, intense echodensity. Forty-nine patients had abnormalities in the periventricular white matter (15 W1, 12 W2, 11 W3 and 11 W4) and 58 had subependymal (B1 = 29) or ventricular bleeding without (B2 = 13) or with dilatation (B3 = 16). Ventilator treatment was significantly associated with both B and W lesions. Low gestational age, low birthweight, small for gestational age, pre-eclampsia and caesarean section were significantly associated with B lesions whereas asphyxia, surfactant treatment, male patient sex and outborn were associate with W lesions; b 1-3 and W 1-4 lesions were thus partly associated with different potential risk factors. The pre- and perinatal potential risk factors could only partly explain the variance in the frequency of B and W lesions, indicating that there are yet unidentified risk factors for intracranial ultrasonographic pathology.