Incidence of apnoea and bradycardia in preterm infants following triple antigen immunization

Ninety-seven preterm infants were immunized with diphtheria-tetanus-pertussis (DTP) prior to discharge from hospital. The mean gestational age at birth was 28.1 weeks (range 24-34) and the mean age at immunization was 80.6 days (range 44–257). Nineteen (20%) infants developed apnoea or bradycardia within 24 h of immunization. The infants who developed apnoea and/or bradycardia had a younger gestational age at birth than those who did not (P= 0.03), were artificially ventilated for longer (P= 0.01) and were more likely to have a diagnosis of chronic lung disease (P= 0.006). In the majority of infants these events were not clinically significant. Two infants who developed concurrent upper respiratory tract infections required additional oxygen and one of them was treated with oral theophylline. In general, it is safe practice to immunize preterm infants with DTP unless otherwise contraindicated. However, it is recommended that cardiorespiratory function is monitored after immunization in very preterm infants who had prolonged ventilatory support and/or chronic lung disease.     

Incidence of apnoea and bradycardia in preterm infants following DTPw and Hib immunization: A prospective study

Objective: To evaluate the incidence and severity of apnoea and bradycardia in hospitalized preterm infants following immunization at 2 months of age, and identify risk factors.
Methodology: A prospective study of 98 preterm infants, of gestational age 24–31 weeks, immunized at approximately 2 months post natal age with diphtheria-tetanus-whole cell pertussis vaccine (DTP_w) in the neonatal intensive care unit (NICU) at King George V Hospital Sydney. Half the infants also received Haemophilus influenzae type b conjugate vaccine (Hib) simultaneously. All infants were monitored for apnoea and bradycardia in the 24 h periods pre- and post immunization.
Results: Only one infant had apnoea and/or bradycardia pre-immunization compared with 17 post immunization. For 12 infants these events were brief, self-limiting and not associated with desaturations (oxygen saturation <90%). However, for five infants (30%) these events were associated with oxygen desaturation and two of these infants required supplemental oxygen. The group that had apnoea and/or bradycardia and the group that did not were not significantly different in terms of gestational age, birth weight and other variables. Infants who received Hib together with DTP_w were less likely to have apnoea and/or bradycardia than those given DTP_w alone.
Conclusion: When considering immunization for preterm infants, the benefits of early immunization must be balanced against the risk of apnoea and bradycardia. We recommend that the cardio-respiratory function of hospitalized infants born at less than 31 weeks gestation be monitored for 48 h post immunization.     

Vagal bradycardia at term

We discuss the case of a newborn boy presenting well into term with severe bradycardic events and sinus pauses up to 5.4 sec. Sinus bradycardia below 80 bpm and sinus pauses or asystole of more than 2 sec are considered pathologic at term. After exclusion of specific causes, the diagnosis of vagal hyper-reflectivity (VHR) was retained, a state caused by unbalance between sympathetic and parasympathetic activity, the latter overriding the former. It is thought to be a functional and transitional anomaly of the sympathetic and vagal tone during the first months of life and may lead to prolonged monitoring and delayed hospital discharge. This form of rare bradycardia can be treated with atropine and allowed in our case immediate resolution of events and safe discharge from hospital.
Conclusion: When VHR is diagnosed, atropine is the treatment permitting resolution of symptomatic episodes of bradycardia and early and safe discharge from hospital.     

Central apnoea and endogenous prostaglandins in neonates

AIM: Central apnoeas without an identifiable precipitating cause frequently occur in the neonatal period. Serious apnoeas should be treated with ventilation-enhancing methylxanthines. Drugs such as opioids or prostaglandins (PGE2) are known to induce apnoea. PGE2 is an endogenous hormone that plays an important role in the regulation of neural activity and a relationship between PGE2 and central apnoeas has been postulated. METHODS: In order to test the hypothesis that the incidence of central apnoeas in preterm infants is related to endogenous PGE concentration, we measured the urinary concentration of PGE2 and PGE-M and determined the number of central apnoeas >10 s/12 h in overnight polygraphy in 18 preterm infants with apnoeas, bradycardias and desaturations, and 18 normal controls. RESULTS: We found 80.6 (SE 6.9) central apnoeas in the study group, and 52.9 (SE 4.1) in the control group (p = 0.002). Urinary PGE2 concentration was 25.9 (SE 6.1) ng/h/1.73 m2 in the control, 31.2 (SE 15.8) ng/h/1.73 m2 in the study group (p = n.s.), PGE-M concentration was 486 (SE 35) ng/h/1.73 m2 in the control and 1132 (SE 131) ng/h/1.73 m2 in the study group (p < 0.0001). There was a significant correlation between the number of central apnoeas and the PGE-M concentration in the study group (r = 0.68, p < 0.0001). CONCLUSION: Our results suggest a relationship between PGE and the respiratory system and open potential therapeutic options for the treatment of central apnoeas in neonates.     

Morphine-related apnoea in CPAP-treated preterm neonates

BACKGROUND: Morphine can be used to treat pain in preterm neonates with CPAP because of its analgetic potency; however, it is known to induce apnoea. AIM: To evaluate this risk of apnoea. METHODS: We retrospectively analysed 91 preterm neonates with CPAP who received morphine intravenously. The incidence of apnoea 4 h before and after morphine administration was compared. The data were analysed for three dosage groups (<0.01, 0.01-0.03 and 0.03 mg/kg) and according to the incidence of apnoea before morphine application. RESULTS: In the whole group (gestational age 29.1+/-2.9 wk, morphine dosage 0.017+/-0.01 mg/kg) we did not find differences in apnoea before and after morphine (0.9+/-1.8 vs 1.1+/-1.8 apnoea). The only significant increase in apnoea was seen in the subgroup of patients receiving > 0.03 mg/kg (0.3+/-0.67 vs 1.5+/-2.5 apnoea). Interestingly, we found a significantly delayed increase in apnoea in the fourth hour. CONCLUSION: Morphine in preterm infants with CPAP is not widely accepted practice until further randomized studies evaluate efficacy and safety. Morphine in a low dosage (相似文献   

Management of apnoea and bradycardia in neonates

Apnoea is common in the preterm infant, particularly those less than 30 weeks gestation. It results from a combination of central and obstructive factors in the otherwise well preterm infant but can also be a sign of underlying pathology: therefore the diagnosis of apnoea of prematurity is one of exclusion. Apnoea and associated bradycardia and hypoxaemia may require cardiovascular resuscitation and may be associated with long term adverse neurodevelopmental sequelae. A variety of physical and pharmacological treatments have been used with the aim of reducing the severity of episodes and ultimately improving long term outcomes. Caffeine is currently the drug of choice in the treatment of apnoea, supplemented in refractory cases by additional mechanical respiratory support. Long term follow up of affected infants within multi-centre trials is key to optimising management strategies.     

Aminophylline versus caffeine citrate for apnea and bradycardia prophylaxis in premature neonates

We investigated the efficacy and adverse effects of aminophylline and caffeine citrate in 180 premature neonates for 10 days and nights. Aminophylline ( n = 98) and caffeine citrate ( n = 82) were equally effective in preventing apnea and bradycardia. The caffeine citrate group had a lower median heart rate on day 3, fewer neonates with tachycardia and a smaller amount of gastric aspirate on day 7. The need for mononasal continuous positive airway pressure and respirator therapy was similar in both groups. We conclude that caffeine citrate is the drug of choice for apnea and bradycardia prophylaxis in premature neonates with a gestational age ≤33 full weeks.     

Alpha-fetoprotein: A marker for recurrent apnoea of prematurity?

Plasma alpha-fetoprotein was measured each week for 28 days on 132 preterm babies who were admitted to an intensive care unit. Reference values were established on 53 of these infants who were relatively normal and whose gestations ranged from 29 to 33.9 weeks. Similar studies were done on 79 of the 132 infants with comparable gestational ages who suffered from hyaline membrane disease, transient tachypnoea, recurrent apnoea or growth retardation. Plasma AFP was significantly raised in those with recurrent apnoea but a reason was not established for this observation. The risk of apnoea persisted until AFP levels had reached the reference range.

Infants with hyaline membrane disease had lower levels of plasma AFP than the recurrent apnoea group but significantly higher values than controls. Babies who are liable to develop recurrent apnoea can probably be identified at birth as their plasma AFP is exceptionally high. These conclusions refer only to babies who receive a maintenance dose of theophylline from the first week.     

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目的初步探索新生儿期几种常见疾病的睡眠呼吸情况及监测呼吸暂停发生情况。方法对2010年4月至8月首都医科大学附属北京儿童医院住院的36例新生儿进行4h多导睡眠监测仪(PSG)检查。结果共发现12例新生儿呼吸暂停,其中11例为阻塞性呼吸暂停,1例中枢性呼吸暂停,另外有1例发生低通气时伴有经皮氧饱和度下降及心动过缓。结论 PSG检查对于研究新生儿疾病,特别是呼吸暂停的诊断及分类有重要的价值。     

‘Propped and prone’ positioning reduces respiratory events in spontaneously breathing preterm infants: A randomised triple crossover study

Aim

We compared effects of infant positioning and feed-rate interventions on respiratory events and oximetry parameters in spontaneously breathing preterm infants born <32 weeks gestation managed in a neonatal unit.

Methods

A randomised triple crossover design was employed. n = 68 infants underwent three test conditions A: control (supine/flat, gravity bolus feeds), B: position intervention (propped/prone) and C: feed-rate intervention (continuous pump feeds) in randomised sequence over three consecutive days. Primary outcomes were number of events (apnoea, bradycardia and desaturation) and percentage time SpO₂ < 80% over 24 h. The secondary outcome was percentage time SpO₂ ≥ 88%. Treatment effects were estimated using linear mixed-effects models.

Results

Propped/prone positioning significantly reduced events and improved percentage time SpO₂ < 80% and ≥88% compared to both other conditions (all P < 0.001). Outcomes for the feed-rate intervention were not significantly different to control.

Conclusions

Alternative infant positioning should be considered in preterm infants managed in the neonatal unit.     

An infant with seizure-related bradycardia and asystole

We describe an infant girl with ictal bradycardia and asystole who died during an episode of seizure, despite anti-epileptic therapy and permanent cardiac pacemaker implantation. The mechanism of ictal bradycardia and the need to recognize it are therefore discussed. Timely cardiac intervention and adequate anticonvulsant therapy are essential for successful management.     

Heart rate changes during gauge feeding of neonates

One hundred and one electrocardiographs (ECGs) were performed on 38 babies, before, during and after gavage feeds. Forty ECGs taken from 22 babies showed a significant bradycardia occurring after tube passage. The risk of this occurring appeared higher with preterms and with babies below 2.5 kg. It is recommended that gavage feeding be restricted to babies above 2.5kg.     

Laryngeal mask airway use during neonatal resuscitation: a survey of practice across newborn intensive care units and neonatal retrieval services in Australian New Zealand Neonatal Network

This is an Australia New Zealand Neonatal Network (ANZNN) wide survey to identify current practice and guide future practice improvement for the use of laryngeal mask airway (LMA) during neonatal resuscitation. An online questionnaire containing 13 questions was sent out to all tertiary neonatal centres (n = 29 units) and neonatal transport units (n = 4) within ANZNN. The non‐tertiary (level‐II) centres were not included. Response from a senior neonatologist at each centre was received and evaluated. Twenty‐two services (67%) had LMA available; of that only, 40% felt the competency of staff to be adequate; and 59% had routine training in LMA use. During neonatal resuscitation, 68% units reported using LMA if endotracheal intubation was unsuccessful after two or more failed intubation attempts and only 18% used it before intubation if face mask ventilation was inadequate. This survey highlighted variations in practice across the tertiary neonatal centres in ANZNN network. One‐third of the units lack LMA availability and the units with LMA, face concerns of underutilisation and lack of skills for its use.     

Clinical versus polysomnographic profiles in children with obstructive sleep apnoea

OBJECTIVE: To examine the clinical and polysomnographic (PSG) profiles of neurologically normal and abnormal children with obstructive sleep apnoea (OSA) and explore the relationship between these profiles. METHODOLOGY: We enrolled 56 children with persistent snoring and OSA for the study, 16 of whom were neurologically abnormal. All children were examined clinically and attended an overnight PSG study. Total clinical scores, PSG scores, and mild/moderate or severe ratings were derived for each child. RESULTS: Comparison of individual PSG parameters with neurological status demonstrated that the abnormal children had significantly increased obstructive apnoea indices, increased desaturation events and lower mean arousal indices compared to their neurologically normal OSA peers. For the neurologically abnormal children, there was a significant correlation between severity ratings of disease according to clinical and PSG profiles (r = 0.56, P = 0.03, sensitivity 82%) using the clinical summary as the gold standard, although the association was less marked in the neurologically normal children (r = -0.08, P = NS, sensitivity 69%). CONCLUSION: Neurologically abnormal children are likely to have more severe abnormalities in selected polysomnographic indices and overall scores. However, the clinical assessment is only likely to reflect this at the severe end of the spectrum. These relationships are not seen in the neurologically normal child, where little or no reliance can be placed upon predicting the severity of the polysomnographic findings from the clinical data. Decisions regarding the severity of disease and treatment should be based on the combined findings of the clinical and PSG data rather than overall clinical and polysomnographic scores or selected clinical and polysomnographic parameters.     

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??High-frequency ventilation ??HFV????as a special mode of mechanical ventilation??has been widely used in treating preterm neonates with hypoxemic respiratory failure. The clinical use??the advantages and disadvantages compared with the conventional mode??and recent clinical evidences of using HFV to prevent BPD and improve the long term pulmonary function are worthy of concern.     

Plasma fibronectin levels in extremely preterm infants in the first 8 weeks of life

Abstract Fibronectin has in the past been considered to function simply as a non-specific plasma opsonin. However, recent studies have demonstrated that this molecule plays an important role in fundamental components of the immune response, for example, neutrophil adhesion, T cell activation and endothelial function. Additionally, fibronectin is important in lung homeostasis where it contributes to alveolar epithelial integrity. In this study plasma fibronectin levels were measured longitudinally in a group of extremely preterm infants, mean gestational age 27 weeks.
Plasma fibronectin levels at birth were significantly lower in the preterm study group than in term controls (mean 91±33 μg/mL compared with 214±62 μg/mL in the term controls, P <0.0001). The preterm cohort demonstrated a more than two-fold rise in plasma fibronectin on days one and two; levels fell almost to baseline values by day three with a subsequent slow rise to a plateau by day 28. No further increase was seen by day 56. This sequence of early changes in fibronectin levels mirrored closely the time course of respiratory distress syndrome. Infants of mothers with pre-eclampsia had significantly lower peak fibronectin levels than in those without ( P = 0.016), and those infants with bronchopulmonary dysplasia showed a trend towards lower basal fibronectin levels ( P = 0.07) and a greater difference between peak and basal levels ( P = 0.05).
Neonates, particularly those born preterm, have blunted immunological responses to infection. Fibronectin plays a key role in immunological responsiveness. The significant changes in fibronectin levels after birth in the preterm neonate are likely to have important pathophysiological consequences. The relationship between alterations in fibronectin after birth, endothelial and epithelial cell function, and respiratory distress syndrome (RDS) remain to be explored.     

Incidence and mechanism of bradycardia during apnoea in preterm infants.

Bradycardia occurred during 363 of 1520 apnoeas of 10 seconds'' duration recorded in 28 preterm infants. The incidence increased with increasing duration of apnoea (10% of 10-14 seconds, 34% of 15-20 seconds, and 75% of greater than 20 seconds, p less than 0.001). This was similar for each type of apnoea--central, mixed, and obstructive. During 133 apnoeas in five infants the time from the start of the apnoea to the onset in the fall in oxygen saturation (mean 6.9 seconds) was significantly related to the onset of the fall in heart rate (mean 9.3 seconds) (r = 0.67, p less than 0.001). Recovery in heart rate coincided with resumption of air flow rather than breathing efforts and preceded the recovery in oxygen saturation. These results suggest that bradycardia occurs during apnoea as a response to falling oxygen saturation, probably through a peripheral chemoreceptor reflex that is manifest when breathing efforts are absent or ineffective.     

Aetiological factors and development in subjects with obstructive sleep apnoea

OBJECTIVE: To examine whether maternal pregnancy complications, adverse birth events, respiratory illnesses, or developmental difficulty were increased in neurologically normal children with obstructive sleep apnoea (OSA) and whether severity of OSA adversely affects the child's development and temperament. METHODOLOGY: Maternal report of perinatal events, respiratory illness and developmental difficulty in 37 children with OSA was contrasted with a comparison group (n = 67). Children with OSA were assessed developmentally (Griffiths Scales), had a parental rating of temperament (Australian Temperament Scale) and attended an overnight polysomnographic sleep study. RESULTS: Children with OSA had an increased prevalence of adverse maternal pregnancy and perinatal events, respiratory disease and developmental concerns. Limited associations were found between the severity of OSA and development or temperament difficulty. CONCLUSIONS: This study suggests a relationship between OSA, though not its severity, and pre/perinatal adversity and child development. Polysomnographic and detailed developmental assessment of community-based samples of children with OSA and control children are necessary to confirm these findings.