Sudden death in the pediatric population is rare. A study based on the Taiwan National Health Insurance Database from 2000 to 2006 revealed the annual sudden death rate was 2.7 per 100,000 in the population aged 1–18 years.1 In infancy, the peak age of sudden infant death syndrome (SIDS) or near death is between the postnatal age of 1 to 4 months2,3; the incidence of SIDS from 1984 to 1993 in Taiwan increased from 0.25 to 0.56 per 1000 live births4; only 1% to 3% of these cases occurred during the first 2 weeks of life.5–8 Most studies about SIDS are focused on the cases occurring during the peak period, and papers concerning the early neonatal near death were few. In this study, 17 patients with early neonatal sudden and unexpected death or near death were collected and the possible etiologies were investigated.
This study waived the need for approval by the Taipei Veterans General Hospital Institutional Review Board. The definition of early neonatal sudden and unexpected death or near death is the occurrence of a “life-threatening” situation within 1 week after birth in newborns who look healthy before the events. During the period of 2001 to 2005, 17 cases of early neonatal sudden death or near death were collected from five medical centers in Taipei, Taiwan. All of them were free from any risk factor such as prematurity, perinatal asphyxia, difficult delivery, or congenital anomalies, and the initial physical examinations revealed nothing particular. Eleven babies were born at level three hospitals; six babies were transferred from local hospitals after events. The demographic data, clinical manifestations, laboratory data, and possible etiologies were retrospectively collected and analyzed. The definition of dehydration was more than 5% of body weight loss within 48 hours after birth.
The characteristics of these 17 patients are summarized in Tables 1 and 2; mean gestational age (GA) was 38.5±1.2 weeks (37–41 weeks), mean birth body weight (BBW) was 2948±328g (2426–3658g) and the male-to-female ratio was 1.14:1 (9:8). The incidence, which was estimated by the 13 inborn patients divided by the total inborn babies in these five centers during the study period was around 1.9 per 10,000 full-term newborns. Fourteen babies (82.3%) were born via vaginal delivery; 12 babies (70.6%) were primigravidae. All patients had no prenatal or perinatal complication, and their delivery courses were smooth. Twelve patients were exclusively breastfed, two had mixed feeding, two were given formula, and one was unknown.
The manifestations of the events were sudden onset of cyanosis in 12 cases, cyanosis with seizure in three cases, and floppiness in two cases. Eleven episodes occurred in the maternity ward and six in the nursery. The median age at events was 26 hours (2–144 hours). Seven events occurred during 8 AM to 4 PM, four during 4 PM to 12 PM, and six events during 0 AM to 8 AM. The postures at events were supine in eight cases, lying on the side occurred in two cases, under the mother's axilla occurred in three cases, and postures were unknown in four cases. Overall, the mortality rate was 41.2% (7/17); another seven patients had neurologic impairment, and three patients were free from sequela. There was no autopsy case. For the nine survivors, no patient had repeated events.
Table 2 shows the possible causative factors: infection in two patients (group B streptococcus meningitis, pneumonia), urea cycle disorder in one patient, hypertrophic cardiomyopathy in one patient, arrhythmia in one patient, hypocalcemia only in one patient, hypocalcemia plus airway obstruction in one patient, dehydration-related diseases in seven patients and unknown causes in the remaining four patients. All of the four patients of unknown etiology experienced the events during the first postnatal day (2∼22 hours) and the body weight change was not recorded at those events. The outcome is also shown in Table 2. Among the 11 rooming-in patients, six patients died, four patients had neurologic sequelae, and one patient was normal at follow-up. On the other hand, for the six patient with the events happening at nursery, one patient died, three patients had epilepsy, and two patients were normal.
Table 3 shows the six babies with dehydration; the average weight loss was 6.9±1.7% (5.1%–10.4%) within the postnatal ages of 20∼47 hours. Among them, one had both hypoglycemia and hypernatremia, two had hypoglycemia, and one had hypernatremia. Five cases were of exclusively breastfed and one baby received mixed-method feeding.
Rooming-in babies comprised two-thirds of the patients (11/17); all of them exclusively received breastfeeding. There were more than one-half of the deaths among rooming-in newborns (6/11). Severe acidosis (pH<7.2) was found in five of eight rooming-in patients.
The reports about early neonatal sudden death or near death are few5–8; this may be due to the scarcity of such cases. In this study, the estimative incidence of early neonatal near miss was around 1.9 per 10,000 deliveries, which is consistent with previous studies.6 These cases should be thoroughly investigated for possible causative etiologies, especially the treatable ones. A variety of possible causes, including infection, anemia, aspiration pneumonia, metabolic disorders, and unknown etiologies had been reported in previous studies.5,6,9 In this study, the possible causative factors were identified in six babies; they were group B streptococcus meningitis, pneumonia, urea-cycle disorder, hypertrophic cardiomyopathy, hypocalcemia, and hypocalcemia plus airway obstruction. Dehydration-related morbidity was the probable causes for another seven patients.
The four events of unknown etiologies occurred during the first postnatal day. One patient had anemia and leukocytosis [13.8g/dl and white blood cell count (WBC) 35,440/cumm], another patient had mildly elevated C-reactive protein (1.73mg/dL) and borderline leukocytosis (WBC 29,800/cumm). Although there were some clues of infection in these two patients, due to the absence of more solid evidence they were allotted to “unknown cause.” SIDS or near death happened unexpectedly; therefore, sometimes there was not sufficient time to thoroughly identify the real causes. To make up this deficiency, autopsy should be advocated; however, due to the culture of our society, all six mortality cases had no autopsy.
For newborn babies, there is a postnatal weight loss primarily due to the contraction of extracellular fluid, the so-called “physiologic dehydration.”2 The weight loss in the first 3-5 days averages 4%–7% and should not exceed 10%–12%.10,11 Macdonald and colleagues12 compared the weight loss in breast feeding and formula feeding babies during the first 2 weeks of life; median weight loss was 3.5% of formula fed and 6.6% of breast fed; 97.5th percentile weight loss was 9.5% of formula fed and 12.8% of breast fed, and the peak weight loss was at the third to fourth postnatal day. Exclusively breast feeding has been advocated in recent years. From 2004 to 2008, in Taiwan, the prevalence of breast feeding during first month increased from 54.2% to 72.9%; the prevalence of exclusively breast feeding during first month increased from 33.2% to 54.3%.13,14 The relationship between exclusively breast feeding and critical weight loss has been described since 198215; case reports and articles about breast feeding with hypernatremic dehydration were published in succession.16–20 Incidence of breast feeding–related dehydration was about 7.7%16; these cases comprised 2%–3% of hospitalized neonates.19 The most common presentations were neonatal jaundice and poor infant suckling. Major complications included acute renal failure, impaired liver function, and coagulating-thrombolytic function imbalance.20 In this study, six of 12 babies with exclusive breast feeding and one baby with mixed feeding had body weight loss >5% during the initial 2 days; these seven patients are summarized in Table 3. Six of them were of primigravidae and four of them had either hypoglycemia, hypernatremia, or both. These findings implied that dehydration with hypoglycemia and/or hypernatremia occurred more frequently during the initial training period of breastfeeding among the unexperienced mothers and the unskillful newborns. To avoid these tragedies, babies with exclusive breastfeeding require meticulous monitoring of feeding status, urine amount, body weight loss, and the general activity.
“Rooming-in care of newborns” and “exclusive breast feeding” have been greatly encouraged recently. The advantages of rooming-in include more convenience for breast-feeding, reinforcement of the attachment between mothers and babies, decrease of infection rate, and cost of baby care.21 On the other hand, the popularization of rooming-in raises new concerns. During the study period of 2001–2005, rooming-in care was not prevalent in our society; however, such cases comprised two-thirds of the study population. Moreover, those rooming-in cases were more prone to have metabolic acidosis (5/8 versus 2/6) and dehydration (5/11 versus 2/6); their mortality rate was higher (6/11 versus 1/6), and survivors without sequela were fewer (1/5 versus 2/5). Therefore, delayed detection of near death is a potential risk for rooming-in care. Early detection of the abnormal manifestation of the rooming-in babies has become a very important issue, especially for the new-hand mothers.
Limitations of this study include insufficient case numbers and incomplete data collection, especially in the referred patients. It was very difficult to collect these cases and their full information because the events always happened suddenly, unexpectedly, and were scattered among different hospitals or clinics. In this study, estimative incidence of near death during the early neonatal period was around 1.9 per 10,000 live births. This is comparable with congenital hypothyroidism, which is the most prevalent inborn error metabolism, and its early detection is achieved through the newborn screening. However, it is not routine care to apply cardio-respiration monitors for every newborn who appears healthy and has no risk factors for sudden death. Thus, to identify the high-risk group is probably one of the effective ways. We suggest newborns receiving rooming-in care should be regarded as a risky group for delayed detection of near death, especially for the primigravida mothers who are inexperienced in baby care. For babies with exclusive breast feeding, insufficient intake leading to excessive dehydration, hypoglycemia, and hypernatremia is possible; all of these may contribute to the early near death. Therefore, prompt awareness of insufficient feeding is another effective way to reduce the occurrence of these tragedies, which requires adequate instruction to caregivers.
All 17 episodes happened throughout the day, a finding different from the traditional SIDS, which occurs mostly in the early morning; this indicated that the pathomechanism of these two entities might be different. The causes of death were determined in 13 patients; with the exception of dehydration, congenital cardiomyopathy or congenital infection was proven at autopsy.
In conclusion, promotion of autopsy to discover the underlying disease can give physicians more information and more experience to prevent or alert caregivers regarding the next unexpected event. Without early detection and early effective resuscitation, the outcome of near death is very grave; therefore, adequate training of caregivers is the fundamental way to avoid this tragedy. A nationwide data collection is required, and autopsy should be advocated for a more informative analysis.
The authors gratefully acknowledge expert help from Wu-Shiun Hsieh, MD, at National Taiwan University Hospital, Chyong-Hsin Hsu, MD, at MacKay Memorial Hospital, and Shu-Chi Mu, MD, PhD, at Shin Kong Wu Ho-Su Memorial Hospital.
This study was supported by Taipei Veterans General Hospital, National Taiwan University Hospital, MacKay Memorial Hospital, Shin Kong Wu Ho-Su Memorial Hospital, Taipei City Hospital, Taipei, Taiwan, R.O.C. The authors have no financial interests to disclose.
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