Apnea Testing Practice to Increase Baseline PaCO2 and Frequency of Blood Gas Analyses

OBJECTIVE

To study the influence of the initial partial pressure of carbon dioxide (PaCO2) and frequency of blood gas analyses on the positivity rate and safety of apnea testing (AT).

DESIGN

A prospective multicenter cohort study.

SETTING

Seven teaching hospitals.

PARTICIPANTS

A total of 55 patients who underwent AT.

INTERVENTIONS

Patients were divided into 2 groups according to their initial PaCO2-the experimental group (≥40 mmHg, 27 patients) and the control group (<40 mmHg, 28 patients). Blood gas analysis was performed at 3, 5, and 8 minutes, and vital signs were taken. AT results and complications were compared between the groups.

RESULTS

The initial PaCO2 of the experimental group was 42.8 ± 2.2 mmHg v 36.4 ± 2.9 mmHg in the controls. The AT positivity rate was 100%. The experimental group needed less time to reach the target PaCO2 than the control group (4.07 ± 1.27 minutes v 5.68 ± 2.06 minutes; p = 0.001). Twenty-six patients (96.3%) in the experimental group reached the target PaCO2 in 5 minutes v 17 in the control group (60.7%) (p = 0.001). Seven patients (12.7%) were unable to complete 8-minute disconnection due to hypotension. The experimental group had a slightly lower incidence of hypotension than the control group, but there was no statistical difference (7.4% v 17.9%, p = 0.245).

CONCLUSION

Increasing the baseline PaCO2 and doing more blood gas analyses can significantly shorten the time needed for AT and improve the AT positivity rate.

Cardiorespiratory monitoring with a wireless and nonadhesive belt measuring diaphragm activity in preterm and term infants: A multicenter non-inferiority study

INTRODUCTION

We determined if the heart rate (HR) monitoring performance of a wireless and nonadhesive belt is non-inferior compared to standard electrocardiography (ECG). Secondary objective was to explore the belt's respiratory rate (RR) monitoring performance compared to chest impedance (CI).

METHOD

In this multicenter non-inferiority trial, preterm and term infants were simultaneously monitored with the belt and conventional ECG/CI for 24 h. HR monitoring performance was estimated with the HR difference and ability to detect cardiac events compared to the ECG, and the incidence of HR-data loss per second. These estimations were statistically compared to prespecified margins to confirm equivalence/non-inferiority. Exploratory RR analyses estimated the RR trend difference and ability to detect apnea/tachypnea compared to CI, and the incidence of RR-data loss per second.

RESULTS

Thirty-nine infants were included. HR monitoring with the belt was non-inferior to the ECG with a mean HR difference of 0.03 beats per minute (bpm) (standard error [SE] = 0.02) (95% limits of agreement [LoA]: [-5 to 5] bpm) (p < 0.001). Second, sensitivity and positive predictive value (PPV) for cardiac event detection were 94.0% (SE = 0.5%) and 92.6% (SE = 0.6%), respectively (p ≤ 0.001). Third, the incidence of HR-data loss was 2.1% (SE = 0.4%) per second (p < 0.05). The exploratory analyses of RR showed moderate trend agreement with a mean RR-difference of 3.7 breaths/min (SE = 0.8) (LoA: [-12 to 19] breaths/min), but low sensitivities and PPV's for apnea/tachypnea detection. The incidence of RR-data loss was 2.2% (SE = 0.4%) per second.

CONCLUSION

The nonadhesive, wireless belt showed non-inferior HR monitoring and a moderate agreement in RR trend compared to ECG/CI. Future research on apnea/tachypnea detection is required.

Incidence of postoperative opioid-induced respiratory depression episodes in patients on room air or supplemental oxygen: a post-hoc analysis of the PRODIGY trial

BACKGROUND

Supplemental oxygen (SO) potentiates opioid-induced respiratory depression (OIRD) in experiments on healthy volunteers. Our objective was to examine the relationship between SO and OIRD in patients on surgical units.

METHODS

This post-hoc analysis utilized a portion of the observational PRediction of Opioid-induced respiratory Depression In patients monitored by capnoGraphY (PRODIGY) trial dataset (202 patients, two trial sites), which involved blinded continuous pulse oximetry and capnography monitoring of postsurgical patients on surgical units. OIRD incidence was determined for patients receiving room air (RA), intermittent SO, or continuous SO. Generalized estimating equation (GEE) models, with a Poisson distribution, a log-link function and time of exposure as offset, were used to compare the incidence of OIRD when patients were receiving SO vs RA.

RESULTS

Within the analysis cohort, 74 patients were always on RA, 88 on intermittent and 40 on continuous SO. Compared with when on RA, when receiving SO patients had a higher risk for all OIRD episodes (incidence rate ratio [IRR] 2.7, 95% confidence interval [CI] 1.4-5.1), apnea episodes (IRR 2.8, 95% CI 1.5-5.2), and bradypnea episodes (IRR 3.0, 95% CI 1.2-7.9). Patients with high or intermediate PRODIGY scores had higher IRRs of OIRD episodes when receiving SO, compared with RA (IRR 4.5, 95% CI 2.2-9.6 and IRR 2.3, 95% CI 1.1-4.9, for high and intermediate scores, respectively).

CONCLUSIONS

Despite oxygen desaturation events not differing between SO and RA, SO may clinically promote OIRD. Clinicians should be aware that postoperative patients receiving SO therapy remain at increased risk for apnea and bradypnea.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT02811302, registered June 23, 2016.

Overnight polysomnography and the recording of sleep and sleep-related respiration in orchestra musicians - possible protective effects of wind instruments on respiration

Our study is the first to objectively assess sleep and sleep-related respiration in orchestra musicians. We hypothesized low sleep quality due to high work demands and irregular work-sleep schedules, and a better respiration for wind instrument (WI) players than string instrument (SI) players due to habitual upper airway muscles training. We recorded overnight polysomnography with 29 professional orchestra musicians (21 men, 14 WI/ 15 SI). The musicians presented a sleep efficiency of 88% (IQR 82-92%) with WI having a significant higher sleep efficiency than SI (89%, 85-93% vs. 85%, 74-89%; p = 0.029). The group had a total sleep time around 6 hours (377min, 340-421min) with signs of increased NREM 1 (light sleep) and decreased REM (dream sleep). The musicians displayed an apnea-hypopnea-index of 2.1events/hour (0.7-5.5) and an oxygen saturation of 98% (97-100%). While SI player exhibited declining sleep-related respiration with age (breathing events: r = 0.774, p = 0.001, oxygen: r = -0.647, p = 0.009), WI player showed improved respiration with age (breathing events: r = -0.548, p = 0.043; oxygen: r = 0.610, p = 0.020). Our study is the first objective investigation of sleep pattern and respiration during sleep with overnight polysomnography in professional orchestra musicians. While sleep and respiration were unexpectedly good, our results revealed possible signs of sleep deprivation and an interesting age-related pattern on respiration depending on instrument. While sample size was small and results modest, these findings present first objective evidence towards the assumption that habitual playing of a WI-and training of the upper airway muscles-may have a protective effect on respiration.

Recent Trends in Infant Car Seat Tolerance Screening Failure Within a Large Health Care System, 2014-2018

OBJECTIVES

To describe temporal trends in car seat tolerance screening (CSTS) failure within a large hospital system (2014-2018).

METHODS

We conducted a retrospective cohort study using electronic medical record data for infants who underwent a CSTS. Our primary outcome measure was the CSTS failure rate. Covariates included year, CSTS location (well nursery or NICU), gestational age (GA), race, sex, birth weight, CSTS date, and age at CSTS. Associations of covariates with CSTS failure were examined by using χ² tests, t tests, analysis of variance, and Wilcoxon rank tests. Multivariable logistic regression was used to determine the adjusted odds of CSTS failure.

RESULTS

Of 4849 infants tested, the failure rate was 8.1% (n = 394). Most CSTS occurred in the well nursery (79.5%) and involved late preterm (55.2%) or term infants (23.7%). In bivariate analyses, year, unit location, higher birth weight, younger chronological age at testing, and higher GA were positively associated with CSTS failure (P < .05). After stratification by CSTS location, the CSTS failure rate rose in the well nursery but remained stable in the NICU, and use of screening rose among term infants. In the adjusted model, year, GA, and corrected gestational age at CSTS were associated with failure. Each subsequent year was associated with a 19% increase in odds of CSTS failure (P < .001).

CONCLUSIONS

We found a higher rate of CSTS failure in the well nursery compared with the NICU, and the difference in failure rates increased over time. Improved understanding of infants at the highest risk of CSTS failure could impact routine screening guidelines.

Association of Serum Albumin With Apnea in Infants With Bronchiolitis: A Secondary Analysis of Data From the MARC-35 Study

IMPORTANCE

Apnea is a rare, life-threatening complication of bronchiolitis, the leading cause of infant hospitalization in the United States. Currently, no objective method exists for identifying which infants will become apneic.

OBJECTIVE

To investigate whether serum albumin levels are associated with apnea in infants with severe bronchiolitis.

DESIGN, SETTING, AND PARTICIPANTS

A secondary data analysis of the 35th Multicenter Airway Research Collaboration, an ongoing multicenter cohort study of infants hospitalized for bronchiolitis, was conducted from December 11, 2018, to May 30, 2019. Seventeen hospitals across the United States enrolled infants (n = 1016) during 3 consecutive bronchiolitis seasons (November 1 to April 30) between 2011 and 2014. Infants with heart-lung disease or a gestational age less than 32 weeks were excluded.

EXPOSURES

Serum albumin level was categorized as low (<3.8 g/dL) or normal (≥3.8 g/dL).

MAIN OUTCOMES AND MEASURES

Apnea during the hospitalization.

RESULTS

Of the 1016 infants hospitalized for bronchiolitis, the median (interquartile range [IQR]) age was 3 (2-6) months, 610 (60.0%) were male, and 186 (18.3%) were born preterm (32-37 weeks' gestation). Among the 25 infants (2.5%) with apnea while hospitalized, the median (IQR) serum albumin level was 3.5 (3.1-3.6) g/dL, and 22 (88.0%) had low serum albumin levels. The prevalence of apnea was 5.7% among all infants with low albumin levels, compared with 0.5% prevalence in infants with normal serum albumin levels. In unadjusted analyses, apnea was associated with younger age, preterm birth, weight-for-age z score, and low albumin (odds ratio [OR], 12.69; 95% CI, 3.23-49.82). After adjustment for age, preterm birth, and weight-for-age z score, low serum albumin levels remained statistically significantly associated with apnea (OR, 4.42; 95% CI, 1.21-16.18).

CONCLUSIONS AND RELEVANCE

Low serum albumin levels appeared to be associated with increased risk of apnea after adjustment for known apnea risk factors. This finding provides a path to potentially identifying apnea, a life-threatening complication of bronchiolitis.

Correlation between cardiorespiratory events and gastro-esophageal reflux in preterm and term infants: Analysis of predisposing factors

BACKGROUND

The association between cardiorespiratory events (CRE) and gastro-esophageal reflux (GER) among neonates is still controversial.

AIMS

To test such an association in preterm and term infants.

STUDY DESIGN

Prospective observational study.

SUBJECTS

Forty-seven infants with suspected GER and recurrent CRE admitted at a neonatal intensive care unit, who underwent simultaneous and synchronized 24-hour recording of heart rate (HR), peripheral oxygen saturation (SpO2) and pH-impedance monitoring (MII-pH). HR/SpO2 data were filtered to avoid artefactual episodes of hypoxia and hypoperfusion.

OUTCOME MEASURES

The main outcome measure was the symptom association probability (SAP), with a 2-minute time window. Infants with positive (>95%) and negative (≤95%) SAP index tests were compared by univariate and multivariate statistics.

RESULTS

Median gestational age at birth was 29^4/7 weeks, median age at study 36 days. We recorded 3341 GER events and 4936 CRE (4710 desaturations, 226 bradycardias); 609/4936 (12%) CRE were temporally associated with GER episodes: 338 preceded and 271 followed GER events. The SAP index was significant in 5/47 (11%) patients. The SAP index including only CRE following GER events was significant in 3/47 (6%). There was no significant difference in the number of acid, weakly acid, non-acid, pH-only events preceding or following CRE between infants with SAP-positive and SAP-negative tests. Infants with positive SAP-index tests compared to those with SAP-negative tests had lower weight gain in the three days preceding the test and tended to have lower birth weight.

CONCLUSIONS

GER and CRE were associated in <11% of patients. The evaluation of ponderal growth might be helpful in predicting such an association.

Investigations for infants admitted with apparent life-threatening event (ALTE): Necessity or liability? Assessment at a tertiary care hospital

The retrospective study was planned to assess the outcome of extensive investigations done for infants admitted with apparent life-threatening event (ALTE), and comprised chart review of 275 infants admitted to King Abdul-Aziz Medical City (KAMC), Riyadh, Saudi Arabia, between 2012 and 2015. The outcome of each investigation was compared in terms of whether the test was performed or not performed, and, if performed, whether the test report was normal or abnormal. Also, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) was assessed for each test. All culture tests, including those of blood, urine and cerebrospinal fluid (CSF), were of little help in contributing to the final diagnosis. Nasopharyngeal aspiration (NPA), chest X-ray and upper gastrointestinal (GI) study were more relevant in terms of finding an underlying cause for ALTE (p=0.01, p=0.04 and p<0.001 respectively). Of the total, 87(32%) subjects did not have a final diagnosis and were considered normal. Gastro-oesophageal reflux 59(22%) and bronchiolitis 58(21%) were the most common diagnoses; both can be diagnosed clinically without any invasive investigations.

Sleep Management Among Patients with Substance Use Disorders

Sleep and substance use disorders commonly co-occur. Insomnia is commonly associated with use and withdrawal from substances. Circadian rhythm abnormalities are being increasingly linked with psychoactive substance use. Other sleep disorders, such as sleep-related breathing disorder, should be considered in the differential diagnosis of insomnia, especially in those with opioid use or alcohol use disorder. Insomnia that is brief or occurs in the context of active substance use is best treated by promoting abstinence. A referral to a sleep medicine clinic should be considered for those with chronic insomnia or when another intrinsic sleep disorder is suspected.

Fluid restriction for treatment of preterm infants with chronic lung disease

BACKGROUND

Fluid restriction is often recommended as part of the management of infants with early or established bronchopulmonary dysplasia (BPD).

OBJECTIVES

To determine whether fluid restriction as part of the therapeutic intervention for early or established BPD improves clinical outcomes.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1) in the Cochrane Library (searched 16 February 2016), MEDLINE via PubMed (1966 to 16 February 2016), Embase (1980 to 16 February 2016), and CINAHL (1982 to 16 February 2016). We also searched clinical trials' databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Prospective randomised clinical trials comparing two distinct fluid administration volumes in preterm infants with early or established BPD.

DATA COLLECTION AND ANALYSIS

We used the standard methods of Cochrane Neonatal. For the included trial, we extracted data and assessed the risk of bias, and used GRADE methods to assess the quality of the evidence. The outcomes considered in this review are effects on mortality or requirement for oxygen at 36 weeks' postmenstrual age (primary outcome measure), the duration of supplemental oxygen therapy, proportion of infants discharged from hospital on oxygen, duration of assisted ventilation, duration of hospitalisation, weight gain, feeding tolerance, apnoea, necrotizing enterocolitis, renal dysfunction or nephrocalcinosis, lung mechanics, and use of diuretic therapy (secondary outcome measures).

MAIN RESULTS

One trial was found, including 60 preterm infants at 28 days of age with persistent oxygen requirements. Infants were randomised to either 180 mL/kg/day of standard formula or 145 mL/kg/day of concentrated formula. This single study did not provide data regarding our primary outcome. No effects of the intervention were found on any of our secondary outcomes. The quality of the evidence from this study was graded low.

AUTHORS' CONCLUSIONS

There is no evidence to support the practice of fluid restriction in infants with early or established BPD.

Daytime sleepiness is associated with hyperhomocysteinemia in rural area of China: A cross-sectional study

OBJECTIVE

To ascertain whether sleep abnormalities including daytime sleepiness, snoring, apnea, sleep disruption and sleep duration abnormity are significantly associated with hyperhomocysteinemia (Hhcy).

METHODS

A total of 5992 participants were involved in the cross-sectional study. Sleep abnormalities were evaluated by a structured questionnaire. Hhcy was defined as plasma levels of homocysteine ≥15μm/L.

RESULTS

After adjustment for age, gender, education, current smoking status and current drinking status, daytime sleepiness (OR, 1.597; 95%CI, 1.210-2.110, P=0.001), sleep duration <6h (OR, 1.273; 95%CI, 1.063-1.524, P=0.009) and sleep duration >8h (OR, 1.205; 95%CI, 1.065-1.364, P=0.003) were significantly associated with Hhcy. While snoring (OR, 1.065; 95%CI, 0.950-1.195, P=0.279), apnea (OR, 1.170; 95%CI, 0.924-1.482, P=0.193), and sleep disruption (OR, 1.065; 95%CI, 0.852-1.331, P=0.580) were not. After further adjustment for body mass index, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, total cholesterol, physical activity, diabetes, coronary heart disease, stroke, depression, glomerular filtration rate, hypertension and hyperuricemia, still the increased OR could be found in the daytime sleepiness group (OR, 1.569; 95%CI, 1.145-2.150, P=0.005). However, sleep duration <6h (OR, 1.067; 95%CI, 0.788-1.445, P=0.676) and sleep duration >8h groups (OR, 1.080; 95%CI, 0.883-1.320, P=0.453) were no longer significantly associated with Hhcy.

CONCLUSIONS

Daytime sleepiness, but not sleep duration abnormity, snoring, apnea and sleep disruption was an independent risk factor for Hhcy.

Seasonal Timing of Infant Bronchiolitis, Apnea and Sudden Unexplained Infant Death

Rates of Sudden Unexplained Infant Death (SUID), bronchiolitis, and central apnea increase in winter in temperate climates. Though associations between these three conditions are suggested, more work is required to establish if there is a causal pathway linking bronchiolitis to SUID through inducing central apnea. Utilizing a large population-based cohort of infants studied over a 20-year period (n = 834,595, from birth years 1989–2009)), we analyzed ecological associations between timing of SUID cases, bronchiolitis, and apnea healthcare visits. Data were analyzed between 2013 and 2015. We used a Cox Proportional Hazards model to analyze possible interactions between maternal smoking and maternal asthma with infant bronchiolitis on time to SUID. SUID and bronchiolitis both occurred more frequently in winter. An increase in bronchiolitis clinical visits occurred within a few days prior to apnea visits. We found a temporal relationship between infant bronchiolitis and apnea. In contrast, no peak in SUID cases was seen during peaks of bronchiolitis. Among those without any bronchiolitis visits, maternal smoking was associated with an increased risk of SUID: Hazard Ratio (HR) of 2.38 (95% CI: 2.11, 2.67, p-value <0.001). Maternal asthma was associated with an increased risk of SUID among infants with at least one bronchiolitis visit: HR of 2.40 (95% CI: 1.04, 5.54, p-value = 0.04). Consistent trends between bronchiolitis, apnea, and SUID were not established due to small numbers of SUID cases. However, interaction analysis revealed potential differential associations of bronchiolitis and SUID by maternal smoking, maternal asthma status.

Risk factors for adverse events after vaccinations performed during the initial hospitalization of infants born prematurely

INTRODUCTION

There are significant delays in implementing vaccination among preterm infants.

OBJECTIVES

Description of the frequency and kinds of adverse events following immunization in preterms. Establishment of the group of preterms who will distinctively be susceptible to adverse events.

MATERIALS AND METHODS

Demographical, clinical data and the occurrence of adverse events after DTaP, HIB and pneumococcal vaccination among preterms during their initial hospitalization were prospectively collected with the use of an electronic data form between 1st June 2011 and 31st May 2015. The analysis was conducted on 138 patients. The groups were divided according to maturity (I: ≤ GA 28w n=73 and GA 29-36 w n=65).

RESULTS

There were no statistically significant differences between the groups in the occurrence of adverse events. Out of the total group, following vaccination apnoea developed in 6 newborns (4%) and activity dysfunctions were observed in 13 newborns (10%). The occurrence of apnoea after vaccination positively correlated with the time of non-invasive ventilation and the occurrence of late infection. There were no statistically significant demographical or clinical risk factors for the development of activity dysfunctions following vaccination.

CONCLUSIONS

Term vaccination in clinically stable preterm infants is a safe medical procedure. However, long-term non-invasive respiratory support and late infections are risk factors for apnea following vaccinations. In these patients vaccinations should be considered during hospitalization.

Long-term effects of pegvisomant on comorbidities in patients with acromegaly: a retrospective single-center study

CONTEXT

The effect of pegvisomant on IGF1 levels in patients with acromegaly is well documented, but little is known of its long-term impact on comorbidity.

AIM

The aim of this retrospective study was to evaluate the effects of long-term pegvisomant therapy on cardiorespiratory and metabolic comorbidity in patients with acromegaly.

PATIENTS AND METHODS

We analyzed the long-term (up to 10 years) effect of pegvisomant therapy given alone (n=19, 45%) or in addition to somatostatin analogues and/or cabergoline (n=23, 55%) on echocardiographic, polysomnographic and metabolic parameters in respectively 42, 12 and 26 patients with acromegaly followed in Bicêtre hospital.

RESULTS

At the first cardiac evaluation, 20±16 months after pegvisomant introduction, IGF1 levels normalized in 29 (69%) of the 42 patients. The left ventricular ejection fraction (LVEF) improved significantly in patients whose basal LVEF was ≤60% and decreased in those whose LVEF was >70%. The left ventricular mass index (LVMi) decreased from 123±25 to 101±21 g/m(2) (P<0.05) in the 17 patients with a basal LVMi higher than the median (91 g/m(2)), while it remained stable in the other patients. Pegvisomant reduced the apnoea-hypopnea index and cured obstructive sleep apnea (OSA) in four of the eight patients concerned. Long-term follow-up of 22 patients showed continuing improvements in cardiac parameters. The BMI and LDL cholesterol level increased minimally during pegvisomant therapy, and other lipid parameters were not modified.

CONCLUSIONS

Long-term pegvisomant therapy not only normalizes IGF1 in a large proportion of patients but also improves cardiac and respiratory comorbidity.

Apparent Life-Threatening Events: Patients' Health Status at 5 Years of Age

BACKGROUND

The long-term significance of apparent life-threatening events (ALTE) has not been thoroughly studied.

OBJECTIVES

To evaluate, at age 5 years, the health status of consecutive children diagnosed with ALTE in infancy.

METHODS

Based on the diagnostic workup, patients were classified into two groups: a 'broad' evaluation group (at least one test/procedure related to each of the five main causes: infectious, metabolic, cardiopulmonary, gastroenterological, neurological), and a 'narrow' workup group whose evaluation did not cover all five domains. Health status around age 5 was obtained from hospital records, community clinics and parents/caregivers.

RESULTS

We identified 132 children with ALTE. Choking (49.2%) was the most common description, followed by apnea (13.6%), suspected seizure (12.9%), cyanosis (12.1%), breath-holding spell (8.3%), and pallor (3.8%). A broad diagnostic workup was performed in 62.1% of the infants, and a narrow workup in 37.9%. At age 5 years, 56.8% of the children were healthy; 27.3% reported chronic conditions unrelated to ALTE. Twenty-one children (15.9%) had unrelated neurodevelopmental conditions, mostly attention deficit disorder. One of the 132 ALTE patients relapsed and was eventually diagnosed with epilepsy.

CONCLUSIONS

A single episode of ALTE in infancy was neither predictive of nor associated with chronic systemic or neurological-disease at age 5 years.

Clinico-epidemiological study of low birth weight newborns in the Eastern part of Nepal

Low birth weight (LBW) remains an important cause of newborn morbidity and mortality. A hospital based prospective and descriptive study was conducted at Paediatric wards, Nursery, Neonatal intensive unit (NICU) and Post natal ward during period of June to October 2010 to note the clinico-epidemiological profile of Low Birth Weight (LBW) newborns. Incidence of the LBW babies in our hospital was 14.45%; more than four fifth (82.2%) baby's mothers were primigravida. Eighty two percent mothers had unbooked pregnancies. Twenty and half percent LBW babies were twins. The mean duration of hospital stay of the subject was 7.4 (± 5.5) days. The mean birth weight of LBW babies was 1648 (± 344) grams. Clinical sepsis, non physiological jaundice and hypoglycaemia were the three most common complications of LBW babies. Antibiotics, oxygen and phototherapy were the three commonest modes of therapy. Majority of children (82.0%) improved and were discharged. Birth weight and gestational age were significantly different between survivors and babies who expired. Primigravida and lesser antenatal visits were important risk factors for Low birth weight babies. Birth weight, gestational age, apnoea and mechanical ventilation were the predictors of outcome.

Apnea in acute bilirubin encephalopathy

Central apnea, defined as cessation of breathing for ≥20s, is frequent in premature infants born at <34 weeks׳ gestation but uncommon among healthy late preterm (34(0/7)-36(6/7) weeks׳ gestation) and term (≥37 weeks׳ gestation) infants, where it is usually a clinical manifestation of a neurological or metabolic problem. There is growing evidence that marked unconjugated hyperbilirubinemia is associated with central apnea in neonates. This article explores the reported association between acute bilirubin encephalopathy and symptomatic apneic events in newborns and the possible mechanisms involved in the pathogenesis of this phenomenon. The prevalence of symptomatic apneic events in reports of acute bilirubin encephalopathy suggests this clinical finding should be considered a sign of bilirubin neurotoxicity.

The incidence and risk factors of apnea in premature infants underwent general anesthesia for cryotherapy or laser photocoagulation for treatment of retinopathy of prematurity at Queen Sirikit National Institute of Child Health

OBJECTIVE

To determine the incidence and risk factors of postoperative apnea in premature infants who received general anesthesia for cryotherapy or laser photocoagulation for treatment of retinopathy of prematurity (ROP) at Queen Sirikit National Institute of Child Health.

MATERIAL AND METHOD

A retrospective cohort study was performed by reviewing medical records of premature infants with ROP who underwent general anesthesia for cryotherapy or laser photocoagulation during January 2008 and December 2010 at Queen Sirikit National Institute of Child Health. The incidence and risk factors of postoperative apnea were analyzed.

RESULTS

Forty of 167 (24%) premature infants had apnea after general anesthesia for treatment of ROP. The risk factors were post-conceptual age and history of apnea. The risk of apnea in patients with post-conceptual age less than 35 weeks was 5.7 times higher than in patients with post-conceptual age more than 37 weeks (95% CI 1.59-20.45). Patients with a prior history of apnea had a 6.42 times greater risk of postoperative apnea compared to patients without a prior history of apnea (95% CI 2.01-20.50). No other serious complications were reported during the study period.

CONCLUSION

The incidence of apnea after general anesthesia in infants with ROP treated with cryotherapy or laser photocoagulation was 24%. The risk factors of postoperative apnea were post-conceptual age less than 35 weeks and prior history of apnea. Patients with risk factors should be closely monitored.

ProSeal™ LMA increases safe apnea period in morbidly obese patients undergoing surgery under general anesthesia

BACKGROUND

Morbidly obese patients are at risk of hypoxemia at the time of induction of anesthesia. The aim of this study was to assess the possible increase in the safe apnea time with the use of ProSeal laryngeal mask airway (PLMA) as a conduit prior to laryngoscope-guided intubation in morbidly obese patients undergoing surgery under general anesthesia.

METHODS

Hundred patients with BMI greater than 35 kg/m2, undergoing surgery under general anesthesia, were randomly divided to receive either PLMA or facemask with oropharyngeal airway (FM) as the airway device. Following preoxygenation with 100% oxygen with continuous positive airway pressure of 10 cm H2O, in ramp position for 5 min the patients were made apneic. From start of apnea to the time to reach SpO2 to 92% was recorded as safe apnea time. Ventilation was initiated and time to reach SpO2 of 100% was recorded as recovery time.

RESULTS

The mean safe apnea time was 205 (96-320)s in FM vs. 337 (176-456) s in PLMA (P = 0.0000). The mean recovery period was 49 (36-68)s in FM vs. 42(30-56)s in PLMA groups (P = 0.0000). Arterial blood gas analysis showed significant difference in pO2 between the two groups.

CONCLUSION

The use of ProSeal laryngeal mask airway prior to laryngoscope-guided intubation is beneficial in increasing safe apnea period and achieving faster recovery from hypoxemia in morbidly obese patients.

Obstructive sleep apnea syndrome: complaints and housing characteristics in a population in the United States

CONTEXT AND OBJECTIVE Obstructive sleep apnea syndrome (OSAS) is one of the leading causes of morbidity and mortality in adults. Early detection of the disorder and discovery of risk factors through standardized questionnaires will lead to reduction of the OSAS burden. The main aim of this study was to estimate the prevalence of OSAS symptoms and examine their association with housing characteristics. DESIGN AND SETTING Cross-sectional study at a medical school. METHODS Demographic, housing and body measurement data on 5,545 individuals aged 16 years and over of various races were selected from the National Health and Nutrition Examination Survey. We analyzed the probability of OSAS based on habitual snoring combined with daytime sleepiness and/or witnessed apnea. Univariate and multiple linear regression were used. RESULTS 9.8% of the men and 6.9% of the women reported symptoms suggestive of OSAS (habitual snoring, daytime sleepiness and/or apnea). The following prevalences of symptoms were found among males and females respectively: frequent snoring 35.1%, 22.3%, excessive daytime sleepiness 6.4%, 3.4% and frequent apnea 14.9%, 20.6%. Using multiple linear regression, OSAS symptoms were correlated with gender, age, body mass index (BMI), marital status and education. Regarding housing characteristics, mildew or musty smell and pets in the environment were associated with a high probability of OSAS. CONCLUSION OSAS symptoms were more prevalent than in developing countries. The environment was an important risk factor, but environmental factors are easier to control and manage than other variables like BMI or socioeconomic status.

Sleep specialists' opinion on sleep disorders and fitness to drive a car: the necessity of continued education

Whether patients with sleep disorders are fit to drive, and who should determine this, is a matter of debate. However, scientific literature is available on these topics to aid clinicians making these decisions. A survey was conducted to assess sleep specialists' views on fitness to drive for patients suffering from apnea, insomnia, and narcolepsy. Most of the 112 respondents (66%, 95%CI: 57-74%) indicated that insomnia patients would be fit to drive within days or weeks after initiating treatment, but 44% (95%CI: 35-53%) felt that, depending on the amount of excessive daytime sleepiness (EDS), they should not drive if untreated. Around half of respondents (49%, 95%CI: 40-58%) indicated that untreated patients with apnea should not drive, but the majority (66%, 95%CI: 57-74%) felt they could drive after Continuous Positive Airway Pressure treatment was established, though EDS was a significant factor. For untreated narcoleptic patients 77% (95%CI: 68-84%) indicated they should not drive, and similarly, that treated patients could drive, although EDS levels were again seen as important. It is concluded that patient education remains the most practical approach to improve compliance and reduce accidents associated with EDS. Sleep specialists should remain up-to-date of relevant scientific literature to achieve this goal.

Anemia, apnea of prematurity, and blood transfusions

OBJECTIVE

To compare the frequency and severity of apneic events in very low birth weight (VLBW) infants before and after blood transfusions using continuous electronic waveform analysis.

STUDY DESIGN

We continuously collected waveform, heart rate, and oxygen saturation data from patients in all 45 neonatal intensive care unit beds at the University of Virginia for 120 weeks. Central apneas were detected using continuous computer processing of chest impedance, electrocardiographic, and oximetry signals. Apnea was defined as respiratory pauses of >10, >20, and >30 seconds when accompanied by bradycardia (<100 beats per minute) and hypoxemia (<80% oxyhemoglobin saturation as detected by pulse oximetry). Times of packed red blood cell transfusions were determined from bedside charts. Two cohorts were analyzed. In the transfusion cohort, waveforms were analyzed for 3 days before and after the transfusion for all VLBW infants who received a blood transfusion while also breathing spontaneously. Mean apnea rates for the previous 12 hours were quantified and differences for 12 hours before and after transfusion were compared. In the hematocrit cohort, 1453 hematocrit values from all VLBW infants admitted and breathing spontaneously during the time period were retrieved, and the association of hematocrit and apnea in the next 12 hours was tested using logistic regression.

RESULTS

Sixty-seven infants had 110 blood transfusions during times when complete monitoring data were available. Transfusion was associated with fewer computer-detected apneic events (P < .01). Probability of future apnea occurring within 12 hours increased with decreasing hematocrit values (P < .001).

CONCLUSIONS

Blood transfusions are associated with decreased apnea in VLBW infants, and apneas are less frequent at higher hematocrits.

Incidence and risk factors for retinopathy of prematurity in the West Black Sea region, Turkey

The objective of this study was to determine the incidence, risk factors and severity of retinopathy of prematurity (ROP) and to establish screening criteria for our region. Data on 330 infants with gestational age at birth < or = 34 weeks were analyzed retrospectively for a ROP diagnosis and risk factors. Infants with type 1 ROP were treated with argon laser photocoagulation. ROP was detected in 106 of 330 infants; 18 infants had type 1 ROP and were treated. Two infants with ROP that progressed to stage 4 disease required surgery. No treatment was needed in infants born after 32 weeks of gestation. Respiratory distress syndrome and low gestational age were the most important risk factors for type 1 ROP. In the West Black Sea region of Turkey, screening all premature infants with a gestational age < or = 32 weeks or a birth weight < or = 1900 g appears to be appropriate.

[Cardiorespiratory events after first immunization in premature infants: a prospective cohort study]

OBJECTIVE

To investigate whether all preterm infants born before 33 weeks of gestation need cardiorespiratory monitoring due to the risk of cardiorespiratory disturbances following their first vaccination at 2 months of age.

DESIGN

A prospective observational cohort study.

METHOD

During a period lasting a little over a year, all preterm infants who were being cared for at the neonatal ward of Medical Centre Alkmaar because they had been born before 33 weeks of gestation received their first immunization at the age of 2 months and were subsequently monitored. Infants who had already been discharged by that time were readmitted for this purpose.

RESULTS

In this cohort of 41 premature infants whose mean gestational age was 30.8 weeks (SD: 1.9), 10 of these had a mild decrease in oxygen saturation or bradycardia; three developed a moderate cardiorespiratory event requiring tactile stimulation. The incidence of disturbances was higher in younger and lower-weight infants and those who had experienced more severe morbidity during the neonatal phase. Moderate disturbances only occurred in the infants who had not yet been discharged from hospital after birth.

CONCLUSION

It is recommended that still-hospitalized premature infants receive their first immunizations under cardiorespiratory monitoring, as events were observed during a period of 0-24 hours thereafter. In premature infants who had already been discharged - mainly because they were less premature or dysmature - immunization without cardiorespiratory monitoring appeared to be safe. Further research is needed for substantiating this strategy.

Physiologic effects of retinopathy of prematurity screening examinations

PURPOSE

Preterm infants weighing less than 1500 g routinely undergo a series of eye examinations to screen for retinopathy of prematurity (ROP). While these examinations are important for the prevention of blindness, infants may suffer adverse physiologic events during and after the examination. The procedure includes administration of mydriatic eye drops that may be absorbed systemically and physical manipulation of the eye that is accompanied by stress and pain. The purpose of the study was to monitor changes in infant health status and adverse physiologic events in the 2 days after ROP eye screening.

SUBJECTS

The study used 50 preterm infants with a mean gestational age of 32 weeks, undergoing their first ROP examination in a NICU located in a university medical center.

DESIGN

This pilot study used a prospective, descriptive design.

METHODS

Physiologic changes and illness events were recorded before and for 2 days after the eye examination, using tools that tracked parameters of respiratory, cardiovascular, gastrointestinal, and neurological status. Data were collected directly from daily audits of medical records. McNemar's test for comparing paired proportions and the signed rank test were used for comparing significance of physiologic changes before and after the ROP eye examination.

PRINCIPAL RESULTS

Apnea events increased significantly (P = .04) in the 24- to 48-hour period after the eye examination compared with apnea events before the eye examination. These results were based on 39 infants who were not receiving ventilator support. There was a significant difference in the frequency of oxygen desaturation events between infants with and without apnea (0-24 hours after examination, P < .002; 25-48 hours after examination, P < .001). There were no significant differences in heart rate, cyanosis, gastric residuals, or seizures after the eye examinations.

CONCLUSIONS

The ROP examinations may be associated with increased apnea, a clinically significant problem. Nursing implications include careful monitoring of infants during and after ROP eye examinations, discharge teaching for caregivers, and continued research on nursing interventions to prevent adverse physiologic events.

Serious bacterial infections in infants who have experienced an apparent life-threatening event

STUDY OBJECTIVE

We determine the incidence of serious bacterial infection in infants presenting to the emergency department (ED) with an apparent life-threatening event.

METHODS

This was a prospective cohort study of infants younger than 12 months who were treated at an urban children's hospital ED during 1 year and who met standard criteria for an apparent life-threatening event. Sociodemographic data, presenting features, diagnostic testing, hospital course, and final diagnosis were collected. Follow-up information was obtained 4 weeks after the visit.

RESULTS

Of the 198 infants enrolled, 44 (22.2%) had evaluation for serious bacterial infection: urine culture 36 (18%), blood culture 38 (19%) and cerebrospinal fluid culture 18 (9%). No infant (0/198; 95% confidence interval 0% to 1.8%) was found to have bacteremia, urinary tract infection, or bacterial meningitis, which was confirmed at the 4-week interview (99% ascertainment). Two infants were found to have enteroviral meningitis.

CONCLUSION

The incidence of serious bacterial infection in this cohort was extremely low. Infants presenting with an apparent life-threatening event need not be subjected to a full serious bacterial infection evaluation routinely.

Gestational cigarette smoke exposure and hyperthermic enhancement of laryngeal chemoreflex in rat pups

Laryngeal chemoreflex (LCR) apnea occurs in infant mammals of many species in response to water or other liquids in the laryngeal lumen. The apnea can last for many seconds, sometimes leading to dangerous hypoxemia, and has therefore been considered as a possible mechanism in the Sudden Infant Death Syndrome (SIDS). We have found recently that this reflex is markedly prolonged in decerebrate piglets and anesthetized rat pups that are warmed 1-3 degrees C above their normal body temperatures. We intermittently exposed pregnant rats to cigarette smoke and examined the LCR in their four- to fifteen-day-old offspring under general anesthesia, with and without whole body warming. During warming, pups of gestationally smoke-exposed dams had significantly longer LCR-induced respiratory disruption than similarly warmed control pups. The results may be significant for the pathogenesis and/or prevention of SIDS as maternal cigarette smoking during human pregnancy and heat stress in infants are known risk factors for SIDS.

The frequency of apneas in premature infants after inguinal hernia repair: do they need overnight monitoring in the intensive care unit?

BACKGROUND

Postoperative apneas are reported in up to 49% of premature infants undergoing anesthesia for inguinal hernia repair. Our current practice is to monitor all of these babies in the intensive care unit (ICU) overnight after surgery. In addition to the considerable expense to the health care system, these cases are cancelled if no ICU bed is available.

METHODS

A retrospective chart review of all premature infants undergoing inguinal hernia repairs over the past 5 years was undertaken. All postoperative apneas were identified. Potential risk factors were evaluated.

RESULTS

Five (4.7%) of 126 premature infants had apneas after inguinal hernia repair. All of these babies had a previous history of apneas. They also had lower weights both at birth (1.08 vs 1.73 kg) and at the time of surgery (3.37 vs 4.4 kg) as well as lower gestational ages (29 vs 32.3 weeks). They were much more likely to have a complicated past medical history. Markers for this included intraventricular hemorrhage, patent ductus arteriosus, bronchopulmonary dysplasia, and requirement for mechanical ventilation and supplemental oxygen after birth. The use of sevoflurane was the only anesthetic factor which had significance.

CONCLUSION

Postoperative apnea in premature infants after inguinal hernia repair using current anesthetic techniques is much less common than previously reported. Infants with prior history of apneas are at highest risk. Other risk factors appear to include gestational age, birth weight, weight at time of surgery, and a complicated neonatal course. Selective use of postoperative ICU monitoring for high-risk patients could result in significant resource and cost savings to the health care system.

[Severe bronchiolitis. Epidemiology and clinical course of 284 patients]

INTRODUCTION

Bronchiolitis is the leading cause of hospital admission and a frequent cause of pediatric intensive care unit (PICU) admission among infants during the winter months. The objective of this study was to analyze the characteristics and clinical course of patients admitted to the PICU for bronchiolitis.

PATIENTS AND METHOD

We performed a descriptive, observational study by clinical chart review of all patients admitted to the PICU for severe bronchiolitis from November 1994 to March 2006.

RESULTS

A total of 284 patients were included. Most were admitted during December and January and 74% had respiratory syncytial virus (RSV) infection. At least one risk factor for severe disease was present in 68% of the patients: the most frequent risk factor was age < 6 weeks (45%), followed by prematurity (30%). Mechanical ventilation was required in 64 of the 284 patients (24%). Mortality was 1.8% and was associated with chronic pre-existing illness (p < 0.001). The factors associated with a greater risk of mechanical ventilation and a longer PICU stay were the association of two or more risk factors (42/284; 15%), the presence of apnea (73/284; 25.7%), and images of pulmonary consolidation or atelectasis on admission chest X-ray (157/284; 55%).

CONCLUSIONS

Most patients admitted for severe bronchiolitis to the PICU are healthy infants whose principal risk factor is young age. The main predictors of severe clinical course during PICU stay are the association of two or more risk factors, the presence of apnea, and pulmonary consolidation on admission chest X-ray. Bronchiolitis-associated mortality is low and is associated with pre-existing chronic illness.

[Incidence and risk factor analysis of neonatal apnea in the representative regions of Guangdong Province]

OBJECTIVE

To conduct an epidemiological survey of the prevalence of neonatal apnoea and and identify its risk factors in Guangdong Province.

METHODS

The epidemiological data of neonatal apnea were collected by means of cluster sampling from 10 representative regions of Guangdong Province, and the risk factors for this condition were analyzed with logistic regression.

RESULTS

In the representative regions chosen for this survey, the incidence of neonatal apnea was 9.85% in the newborn infants, suggesting a generally similar picture of its prevalence in Guangdong Province. Maternal heart disease and anaemia, number of miscarriages, fetal position and present, oxytocin application, vacuum extraction, prolonged second stage of labor, and number of cesarean delivery were identified as the risk factors for neonatal apnoea, whereas number of pregnancies, the last antenatal examination prior to delivery, high-level antenatal examination hospital, antenatal examination times, and number of normal deliveries were the protective factors. Abnormal amniotic fluid, premature birth, and cord around the neck were the most important risk factors for neonatal apnoea, and adequate amniotic fluid volume is the protective factors for neonatal apnoea.

CONCLUSION

Rigorous control of the risk factors and enhancement of the protective factors can reduce or even prevent the incidence of neonatal apnoea.

Primary immunization of premature infants with gestational age <35 weeks: cardiorespiratory complications and C-reactive protein responses associated with administration of single and multiple separate vaccines simultaneously

OBJECTIVE

To determine the incidence of cardiorespiratory events and abnormal C-reactive protein (CRP) level associated with administration of a single vaccine or multiple separate vaccines simultaneously.

STUDY DESIGN

Prospective observational study on 239 preterm infants at > or =2 months of age in the neonatal intensive care unit (NICU). Each infant received either a single vaccine or multiple vaccines on one day. CRP levels and cardiorespiratory manifestations were monitored for 3 days following immunization.

RESULTS

Abnormal elevation of CRP level occurred in 85% of infants administered multiple vaccines and up to 70% of those given a single vaccine. Overall, 16% of infants had vaccine-associated cardiorespiratory events within 48 hours postimmunization. In logistic regression analysis, abnormal CRP values were associated with multiple vaccines (OR, 15.77; 95% CI 5.10-48.77) and severe intraventricular hemorrhage (IVH) (OR, 2.28; 95% CI 1.02-5.13). Cardiorespiratory events were associated marginally with receipt of multiple injections (OR, 3.62; 95% CI 0.99-13.25) and significantly with gastroesophageal reflux (GER) (OR, 4.76; 95% CI 1.22-18.52).

CONCLUSION

CRP level is expected to be elevated in the 48 hours following immunization. In a minority of infants immunized, cardiorespiratory events were associated with presumed need for intervention. Underlying medical conditions and possibly multiple injections are associated with cardiorespiratory events. Precautionary monitoring following immunizations is warranted.

OSAS in Down syndrome: T&A versus T&A plus lateral pharyngoplasty

OBJECTIVE

Obstructive Sleep Apnea Syndrome (OSAS) is common in children with Down syndrome (DS). Adenotonsillectomy (T&A) has traditionally been the initial surgical treatment. More aggressive surgery has also been recommended. Previous studies have used parental reporting and not objective data to assess treatment outcomes. Polysomnography (PSG) is used to objectively evaluate the results of T&A versus T&A plus lateral pharyngoplasty in the initial treatment of OSAS in children with DS.

METHODS

This is a retrospective study of children with OSAS and DS. Group 1 consisted of 21 children with DS who underwent T&A. Group 2 consisted of 16 children of similar age who had T&A plus lateral pharyngoplasty as initial surgical treatment. Post-operative PSG's were available for all patients. Apnea/hypopnea index (AHI), presence of hypoxemia and hypercarbia, and arousal index were measured and compared.

RESULTS

In group 1, after T&A, 48% continued to have an elevated AHI. If hypercarbia and hypoxemia are included in the result analysis, 67% continued to have abnormal PSG's after their surgery. In group 2, 63% had an elevated AHI post-operatively. When hypercarbia and hypoxemia are included in the analysis, 75% continued to have abnormal PSG's after surgery. There was no statistically significant difference in the outcome of the two groups.

CONCLUSIONS

Pediatric patients with OSAS and DS may show improvement after T&A, however only about one third will have a normal post-operative sleep study. Adding a lateral pharyngoplasty does not improve these results. Further study with objective outcome data is needed to determine a better first line surgical treatment for these patients.

Preliminary investigation of swallowing apnea duration and swallow/respiratory phase relationships in individuals with cerebral vascular accident

Swallowing apnea duration (SAD) and swallow-respiratory phase relationships were examined in individuals with cerebral vascular accident (CVA) and dysphagia who aspirated (n=11) and did not aspirate (n=15). Simultaneous videofluoroscopic and respiratory measures were recorded across 5-, 10-, 15-, and 20-ml thin and thick liquid bolus trials. These data were also compared with that previously acquired with healthy older adults (n=20). A moderate amount of systematic missing data was evidenced in the individuals who were dysphagic and especially those who aspirated subsequently limiting inferential analyses. Only 1 of the 11 participants who aspirated and 7 of the 15 who did not aspirate completed all 16 conditions. Six of the remaining ten who aspirated had missing data subsequent to termination of trials due to aspiration risk. The remaining four and seven of the eight who did not aspirate had missing data due to poor respiratory waveforms. From the remaining data, it was found that SAD and respiratory phase relationships differed among individuals with dysphagia and CVA (i.e., those who aspirate vs. those who do not aspirate) and healthy older adults. SAD was found to be longer for those who aspirated versus those who did not for all bolus viscosities and volumes with the exception of thick-liquid 10-ml boluses. In addition, SAD from those that aspirated was twice as long as that found in healthy older adults for all conditions. Regarding respiratory phase relationships, there was a difference between the proportions of respiratory patterns in those who aspirated versus those who did not. Those who aspirated demonstrated a markedly greater percentage of swallows that interrupted inhalation. In addition, the inhale-swallow-inhale pattern occurred with a greater frequency as swallowing severity increased. Healthy older adults, those who did not aspirate, and those who aspirated used the inhale-swallow-inhale pattern 0.1%, 3.0%, and 9.0%, respectively.

EEG arousal norms by age

STUDY OBJECTIVES

Brief arousals have been systematically scored during sleep for more than 20 years. Despite significant knowledge concerning the importance of arousals for the sleep process in normal subjects and patients, comprehensive age norms have not been published.

METHODS

Seventy-six normal subjects (40 men) without sleep apnea or periodic limb movements of sleep, aged 18 to 70 years, slept in the sleep laboratory for 1 or more nights. Sleep and arousal data were scored by the same scorer for the first night (comparable to clinical polysomnograms) and summarized by age decade.

RESULTS

There were no statistically significant differences for sex or interaction of sex by age (p > .5 for both). The mean arousal index increased as a function of age. Newman-Keuls comparisons (.05) showed arousal index in the 18- to 20-year and 21- to 30-year age groups to be significantly less than the arousal index in the other 4 age groups. Arousal index in the 31-to 40-year and 41-to 50-year groups was significantly less than the arousal index in the older groups. The arousal index was significantly negatively correlated with total sleep time and all sleep stages (positive correlation with stage 1 and wake).

CONCLUSIONS

Brief arousals are an integral component of the sleep process. They increase with other electroencephalographic markers as a function of age. They are highly correlated with traditional sleep-stage amounts and are related to major demographic variables. Age-related norms may make identification of pathologic arousal easier.

Why do ALTE infants not die in SIDS?

AIM

To compare known risk factors for sudden infant death syndrome (SIDS) amongst infants with apparent life threatening events (ALTE) with their matched controls, and ALTE infants who subsequently died of SIDS with infants surviving an ALTE.

METHODS

Questionnaires with replies were obtained from 58 ALTE infants and 56 sex and age matched ALTE control infants. 244 SIDS cases and 868 SIDS controls were used as comparison.

RESULTS

The incidence of ALTE was found to be 1.9% among SIDS controls, but 7.4% among infants who later on died of SIDS. The parents sought medical advice in 0.9% vs 3.7%. ALTE infants did not differ from their matched controls. In the ALTE group 13.3% of the survivors had the combination of prone sleeping and maternal smoking compared with 33.3% of those who became SIDS victims.

CONCLUSIONS

Our results show some major differences between the ALTE infants and SIDS victims not supporting that these conditions belong to the same entity. However, we cannot exclude the possibility that there is a subpopulation of ALTE infants who did not die in SIDS due to that they were sleeping on the back and not exposed to nicotine.

Factors influencing apnea and bradycardia of prematurity - implications for neurodevelopment

BACKGROUND

Apnea and bradycardia of prematurity (ABP) are possible risks towards damage of the developing brain.

OBJECTIVES

To characterize the influence of neonatal factors on ABP and to determine the relationship of ABP to neurodevelopmental outcome.

METHODS

ABP was described in very low birth weight infants (n = 83) using the frequency and severity of ABP episodes with a clinical score considering heart rate, oxygenation, duration and interventions performed during each episode. Neonatal factors were analyzed for their relationship to ABP using regression analysis. Neurodevelopment was investigated using the Mental Developmental Index (MDI) and Psychomotor Developmental Index (PDI) of the Bayley Scales of Infant Development II at a corrected age of 13 months. Power of ABP parameters to predict outcome was assessed by logistic regression analysis.

RESULTS

ABP typically started within the first week after birth. Spontaneous resolution occurred at a postmenstrual age (PMA) of 36.0 +/- 2.2 (31.1-44.1) weeks. A delayed resolution (>36 weeks PMA) and a higher average daily ABP score during a defined developmental period (31-37 weeks PMA) were associated with a higher incidence of unfavorable outcome (MDI or PDI <69 or death).

CONCLUSION

ABP is an age-specific phenomenon. However, more severe courses than expected for PMA or the resolution at a later PMA indicated an increased risk of neurodevelopmental disturbances at a corrected age of 13 months.

Apnea in infants

OBJECTIVE

The main objective of this study was to describe frequency of risk factors in newborns who present different types of apnea in polysomnographic (PSG) recordings in neonatal care units.

METHODS

The study was carried out in neonatal care units of a perinatal tertiary level institution in Mexico City between August 2002 and August 2003. Infants were selected from among 223 infants if they presented any type of apnea event in sleep PSG recordings.

RESULTS

Nearly 25% of patients from a neonatal care unit presented apnea events. Infants with apnea showed lower values of age, weight, and cephalic perimeter at birth than infants without apnea, but did not show more neurologic risk factors. Central apnea events were more frequent in infants with preterm birth (birthweight < 1,500 g), obstructive apnea events were observed in infants with hyperbilirubinemia and gastro-esophageal reflux, while mixed events were seen in infants with sepsis, and hyperbilirubinemia. Sleep PSG recordings detected that 36% of infants with apnea have no previous clinic suspicion of the problem.

CONCLUSION

Central events of apnea were found more frequent in infants with preterm birth, obstructive events in newborns with hyperbilirubinemia and gastroesophagic reflux, while infants mixed apnea had more frequent hyperbilirubinemia and sepsis.

Use of the oculocardiac reflex to assess vagal reactivity during quiet sleep in neonates

Arousal from sleep can be a protective response to life-threatening stimuli. Hence, faults within state-switching processes may lead to fatal events. To investigate the role of the nervous system during cardiac failure triggered by phasic, vagally mediated stimulation, we analysed autonomic and behavioural reactions in 50 premature neonates during quiet sleep (QS) -- a sleep state characterized by a preponderance of tonic, parasympathetic activity. Bradycardia was induced with a standardized ocular compression test. Neither awakening nor behavioural escape reactions were observed during or after an episode of bradycardia. Eighty-six per cent of the provoked bradycardic episodes induced central apnoea. During QS, the neonates' respiratory response and arousability were found to be time-dependent: when the test was performed early in the QS episode, apnoea was more frequent (94%), and no sleep state change occurred. When ocular compression was performed in the later part of the QS episode, a transition towards active sleep was observed, together with significantly fewer episodes of apnoea (64%). These results indicate that a progressive decrease in the respiratory system's responsiveness to phasic, parasympathetic stimulation occurs during QS, whereas arousability increases. Our study suggests that newborns could be more vulnerable to potentially fatal events during the initial portion of a QS episode.

Demystifying Sudden Unexplained Death in Epilepsy?Are We Close?

The cause of sudden unexplained death in epilepsy (SUDEP) is still elusive, despite multiple studies over the past few decades. This review assesses recent progress in the understanding of risk factors (situations that predispose patients to SUDEP) and terminal events (events immediately associated with death) that potentially contribute to SUDEP. Recent studies strongly support a close relationship between seizure episodes (especially generalized convulsions) and SUDEP. The lethal nature of some seizure-induced cardiorespiratory events has been documented fortuitously in rare patient cases, and these events have been consistently reproduced in SUDEP animal models. Nonetheless, SUDEP likely does not have a single cause, and risk factors identified thus far may vary in importance among persons with epilepsy. In the absence of a complete understanding of the pathophysiologic mechanisms underlying SUDEP, potential preventive measures for high-risk patients are offered for consideration. Seizure control is most important for reducing SUDEP risk. Circumstantial data suggest that heightened supervision of patients with frequent seizures may be beneficial. Relatively simple interventions may be sufficient to interrupt potentially lethal events such as periictal suffocation or apnea. However, application of these preventive measures to all epilepsy patients has not been proven to substantially reduce the rate of SUDEP. Additional clinical and laboratory investigations are needed to identify and confirm pathogenic factors and preventive measures.

Recurrent hypoxemia in children is associated with increased analgesic sensitivity to opiates

BACKGROUND

Postsurgical administration of opiates in patients with obstructive sleep apnea (OSA) has recently been linked to an increased risk for respiratory complications. The authors have attributed this association to an effect of recurrent oxygen desaturation accompanying OSA on endogenous opioid mechanisms that, in turn, alter responsiveness to subsequent administration of exogenous opiates. In a retrospective study, the authors have shown that oxygen desaturation and young age in children with OSA are correlated with a reduced opiate requirement for postoperative analgesia.

METHODS

The current study was designed to test that conclusion prospectively in 22 children with OSA scheduled to undergo adenotonsillectomy. The children were stratified to those having displayed < 85% or > or = 85% oxygen saturation nadir during sleep preoperatively. Using a blinded design, the children were given morphine postoperatively to achieve an identical behavioral pain score.

RESULTS

As compared with children in the > or = 85% group, the < 85% oxygen saturation nadir group required one half the total analgesic morphine dose postoperatively, indicating heightened analgesic sensitivity to morphine after recurrent hypoxemia.

CONCLUSIONS

Previous recurrent hypoxemia in OSA is associated with increased analgesic sensitivity to subsequent morphine administration. Therefore, opiate dosing in children with OSA must take into account a history of recurrent hypoxemia.

Heart rate response to respiratory events with or without leg movements

STUDY OBJECTIVE

This study compares the heart rate responses to the termination of respiratory events, both with and without associated leg movements.

METHODS

Heart rate was measured for 15 R-R intervals before (T-15 to T-1) and after (T+1 to T+15) the termination of respiratory events as a change from the baseline rate, defined as the average of 10 R-R intervals occurring before the termination of each respiratory event (T-15 to T-6). Individual heart rate changes of the 21 patients were then averaged separately for 10 respiratory events with and 10 without associated leg movements.

SETTING

N/A.

PARTICIPANTS

Twenty-one patients with obstructive sleep apnea who had respiratory events both with and without associated leg movements.

INTERVENTION

N/A.

RESULTS

Maximal heart rate rise for respiratory events with leg movements (7.9 beats per minute) was significantly greater than for respiratory events without leg movements (5.1 beats per minute) (p < .0001). The area under the curve for heart rate increase from T-5 to T+9 was 50.1% higher for respiratory events with leg movements than without leg movements. When respiratory events with and without accompanying leg movements were compared, there were no significant differences in mean duration of respiratory events, mean oxygen desaturation after respiratory events, mean duration of electroencephalogram arousal following respiratory events, or mean heart rate during the baseline period. Heart rate rise did correlate with duration of the leg movements (p < .001) in those respiratory events with leg movements.

CONCLUSIONS

Cardiac activation is significantly greater when the termination of respiratory events is associated with leg movements compared to those without leg movements. This exaggerated heart rate response may be an independent consequence of the leg movements themselves, as other features of the respiratory events and associated arousal were not different in the two conditions.

Comparison of respiratory physiologic features when infants are placed in car safety seats or car beds

OBJECTIVE

The objective of this study was to compare the respiratory physiologic features of healthy term infants placed in either a car bed or a car safety seat.

METHODS

Within the first 1 week of life, 67 healthy term infants were recruited and assigned randomly to be monitored in either a car bed (33 infants) or a car safety seat (34 infants). Physiologic data, including oxygen saturation and frequency and type of apnea, were obtained and analyzed in a blinded manner.

RESULTS

The groups spent similar amounts of time in the devices (car bed: 71.6 minutes; car seat: 74.2 minutes). The mean oxygen saturation values were not different between the groups (car bed: 97.1%; car seat: 97.3%). The percentages of time with oxygen saturation of < 95% were also similar for the 2 groups (car bed: 11.8[corrected]%; car seat: 18.3[corrected]%). In both groups, a number of infants spent high percentages of study time with oxygen saturation of < 95%. The 6 infants with the most time at this level were all in the car safety seat group (54%-63% of study time). Values for the 6 infants in the car bed group with the most time at this level were lower (20%-42%). This difference in the duration of oxygen saturation of < 95% was not statistically significant. The mean end-tidal carbon dioxide levels and the numbers of episodes of apnea were similar for the 2 groups.

CONCLUSIONS

The respiratory physiologic features of infants in the 2 car safety devices were observed to be similar. Of note, substantial periods of time with oxygen saturation of < 95% were surprisingly common in both groups.