Apnea Events Research Articles

Validation of non-invasive monitoring device to evaluate sleep quality.

This paper presents the validation of a noninvasive sleep monitoring device and sleep quality evaluation. The system is based on an array of pressure sensors positioned on the bed that can measure relevant parameters to estimate sleep quality. This device can measure time in bed (TB), body movements (BM), the thorax expansion, periods out of bed (POB) and apnea events. We compare the results of the unobtrusive pressure sensor array with traditional polysomnography (PSG). The algorithms developed for the device provide a very good detection of all the parameters required to estimate sleep quality as compared to the gold-standard data for a study of 30 patients. For the periods out of bed it presents a sensibility (Se) and specificity (Sp) of 100%. To grade the severity of sleep apnea we compare the number of events per hour or apnea-hypopnea index (AHI) obtained by the device and the PSG; obtaining a Se of 94% and a Sp of 61%. These results validate the use of the device for screening of sleep apnea disease.

Studies about the correlation of sleep apnea hypopnea syndrome with symptomatic cerebral artery stenosis

To investigate the possible correlation of sympotoms of cerebral artery stenosis and sleep apnea hypopnea syndrome. A total of 131 patients that proved to suffer from cerebral artery stenosis by digital subtraction angiography (DSA) were enrolled.These patients were divided into three groups according to the position of cerebral artery stenosis (Group A: internal carotid artery stenosis; Group B : vertebral basilar artery stenosis; Group C: internal carotid artery and vertebral basilar artery stenosis). All the patients underwent apolysomnography(PSG) and correlative parameters were compared. Of 131 cases of cerebral artery stenosis, SAHS patients was up to 106 cases (81%). The incidence of SAHS between the three groups had no significant difference. But the apnea hypopnea index (AHI), the average oxygen desaturation index (AODI) of group B and group C were higher than those of group A. The events of sleep apnea of Group C is higher than Group A. There is a high morbidity rate of SAHS in patients with symptomatic cerebral artery stenosis. The morbidity rate of SAHS has no significant difference with the section of vascular stenosis. But the degree of SAHS is heavier in the patients that with vertebral basilar artery stenosis, internal-vertebral basilar artery stenosis, the lateral appears to experience various types of apnea events.

Predictors of Delayed Postoperative Respiratory Depression Assessed from Naloxone Administration.

The aim of this study was to identify patient and procedural characteristics associated with postoperative respiratory depression or sedation requiring naloxone intervention. We identified patients who received naloxone to reverse opioid-induced respiratory depression or sedation within 48 hours after discharge from anesthetic care (transfer from the postanesthesia care unit or transfer from the operating room to postoperative areas) between July 1, 2008, and June 30, 2010. Patients were matched to 2 control subjects based on age, sex, and exact type of procedure performed during the same year. A chart review was performed to identify patient, anesthetic, and surgical factors that may be associated with risk for intervention requiring naloxone. In addition, we identified all patients who developed adverse respiratory events (hypoventilation, apnea, oxyhemoglobin desaturation, pain/sedation mismatch) during phase 1 anesthesia recovery. We performed conditional logistic regression taking into account the 1:2 matched set case-control study design to assess patient and procedural characteristics associated with naloxone use. We identified 134 naloxone administrations, 58% within 12 hours of discharge from anesthesia care, with an incidence of 1.6 per 1000 (95% confidence interval [CI], 1.3-1.9) anesthetics. The presence of obstructive sleep apnea (odds ratio [OR] = 2.45; 95% CI, 1.27-4.66; P = 0.008) and diagnosis of an adverse respiratory event in the postanesthesia recovery room (OR = 5.11; 95% CI, 2.32-11.27; P < 0.001) were associated with an increased risk for requiring naloxone to treat respiratory depression or sedation after discharge from anesthesia care. After discharge from anesthesia care, patients administered naloxone used a greater median dose of opioids (10 [interquartile range, 0-47.1] vs 5 [0-24.8] IV morphine equivalents, P = 0.020) and more medications with sedating side effects (n = 41 [31%] vs 24 [9%]; P < 0.001). Obstructive sleep apnea and adverse respiratory events in the recovery room are harbingers of increased risk for respiratory depression or sedation requiring naloxone after discharge from anesthesia care. Also, patients administered naloxone received more opioids and other sedating medications after discharge from anesthetic care. Our findings suggest that these patients may benefit from more careful monitoring after being discharged from anesthesia care.

Periodontitis and Sleep Disordered Breathing in the Hispanic Community Health Study/Study of Latinos.

To investigate the association between sleep disordered breathing (SDB) and severe chronic periodontitis. Cross-sectional data analysis from the Hispanic Community Health Study/Study of Latinos. Community-based setting with probability sampling from four urban US communities. 12,469 adults aged 18-74 y. None. Severe chronic periodontitis was defined using the Centers for Disease Control and Prevention/American Academy of Periodontology case classification based on full-mouth periodontal assessments performed by calibrated dentists. SDB was evaluated in standardized home sleep tests, and defined as the number of apnea plus hypopnea events associated with ≥ 3% desaturation, per hour of estimated sleep. SDB was quantified using categories of the apnea-hypopnea index (AHI): 0.0 events (nonapneic); 0.1-4.9 (subclinical); 5.0-14.9 (mild); and ≥ 15 (moderate/severe). Covariates were demographic characteristics and established periodontitis risk factors. C-reactive protein was a potential explanatory variable. Using survey estimation, multivariable binary logistic regression estimated odds ratios (OR) and 95% confidence limits (CL). Following adjustment for confounding, the SDB and periodontitis relationship remained statistically significant, but was attenuated in strength and no longer dose-response. Compared with the nonapneic referent, adjusted odds of severe periodontitis were 40% higher with subclinical SDB (OR = 1.4, 95% CL: 1.0, 1.9), 60% higher with mild SDB (OR = 1.6, 95% CL: 1.1, 2.2) and 50% higher with moderate/severe SDB (OR = 1.5, 95% CL: 1.0, 2.3) demonstrating an independent association between SDB and severe periodontitis. This study identifies a novel association between mild sleep disordered breathing and periodontitis that was most pronounced in young adults.

Pulse oximetry recorded from the Phone Oximeter for detection of obstructive sleep apnea events with and without oxygen desaturation in children.

Obstructive sleep apnea (OSA) disrupts normal ventilation during sleep and can lead to serious health problems in children if left untreated. Polysomnography, the gold standard for OSA diagnosis, is resource intensive and requires a specialized laboratory. Thus, we proposed to use the Phone Oximeter™, a portable device integrating pulse oximetry with a smartphone, to detect OSA events. As a proportion of OSA events occur without oxygen desaturation (defined as SpO2 decreases ≥ 3%), we suggest combining SpO2 and pulse rate variability (PRV) analysis to identify all OSA events and provide a more detailed sleep analysis. We recruited 160 children and recorded pulse oximetry consisting of SpO2 and plethysmography (PPG) using the Phone Oximeter™, alongside standard polysomnography. A sleep technician visually scored all OSA events with and without oxygen desaturation from polysomnography. We divided pulse oximetry signals into 1-min signal segments and extracted several features from SpO2 and PPG analysis in the time and frequency domain. Segments with OSA, especially the ones with oxygen desaturation, presented greater SpO2 variability and modulation reflected in the spectral domain than segments without OSA. Segments with OSA also showed higher heart rate and sympathetic activity through the PRV analysis relative to segments without OSA. PRV analysis was more sensitive than SpO2 analysis for identification of OSA events without oxygen desaturation. Combining SpO2 and PRV analysis enhanced OSA event detection through a multiple logistic regression model. The area under the ROC curve increased from 81% to 87%. Thus, the Phone Oximeter™ might be useful to monitor sleep and identify OSA events with and without oxygen desaturation at home.

An ECG oximetry system for identifying obstructive and central apnoea events.

An automatic algorithm for processing simultaneously acquired electrocardiogram (ECG) and oximetry signals that identifies epochs of pure central apnoea, epochs containing obstructive apnoea and epochs of normal breathing is presented. The algorithm uses time and spectral features from the ECG derived heart-rate and respiration information, as well as features capturing desaturations from the oximeter sensor. Evaluation of performance of the system was achieved by using leave-one-record-out cross validation on the St. Vincent's University Hospital / University College Dublin Sleep Apnea Database from the Physionet collections of recorded physiologic signals. When classifying the three epoch types, our system achieved a specificity of 80%, a sensitivity to central apnoea of 44% and sensitivity to obstructive apnoea of 35%. A sensitivity of 81% was achieved when the central and obstructive epochs were combined into one class.

Obstructive sleep apnoea syndrome.

Obstructive sleep apnoea syndrome (OSAS) is a common clinical condition in which the throat narrows or collapses repeatedly during sleep, causing obstructive sleep apnoea events. The syndrome is particularly prevalent in middle-aged and older adults. The mechanism by which the upper airway collapses is not fully understood but is multifactorial and includes obesity, craniofacial changes, alteration in upper airway muscle function, pharyngeal neuropathy and fluid shift towards the neck. The direct consequences of the collapse are intermittent hypoxia and hypercapnia, recurrent arousals and increase in respiratory efforts, leading to secondary sympathetic activation, oxidative stress and systemic inflammation. Excessive daytime sleepiness is a burden for the majority of patients. OSAS is also associated with cardiovascular co-morbidities, including hypertension, arrhythmias, stroke, coronary heart disease, atherosclerosis and overall increased cardiovascular mortality, as well as metabolic dysfunction. Whether treating sleep apnoea can fully reverse its chronic consequences remains to be established in adequately designed studies. Continuous positive airway pressure (CPAP) is the primary treatment modality in patients with severe OSAS, whereas oral appliances are also widely used in mild to moderate forms. Finally, combining different treatment modalities such as CPAP and weight control is beneficial, but need to be evaluated in randomized controlled trials. For an illustrated summary of this Primer, visit: http://go.nature.com/Lwc6te.

Central sleep apnoea in congestive heart failure

Central sleep apnoea in congestive heart failure

Neural Respiratory Drive and Arousal in Patients with Obstructive Sleep Apnea Hypopnea.

It has been hypothesized that arousals after apnea and hypopnea events in patients with obstructive sleep apnea are triggered when neural respiratory drive exceeds a certain level, but this hypothesis is based on esophageal pressure data, which are dependent on flow and lung volume. We aimed to determine whether a fixed threshold of respiratory drive is responsible for arousal at the termination of apnea and hypopnea using a flow independent technique (esophageal diaphragm electromyography, EMGdi) in patients with obstructive sleep apnea. Sleep center of state Key Laboratory of Respiratory Disease. Seventeen subjects (two women, mean age 53 ± 11 years) with obstructive sleep apnea/hypopnea syndrome were studied. We recorded esophageal pressure and EMGdi simultaneously during overnight full polysomnography in all the subjects. A total of 709 hypopnea events and 986 apnea events were analyzed. There was wide variation in both esophageal pressure and EMGdi at the end of both apnea and hypopnea events within a subject and stage 2 sleep. The EMGdi at the end of events that terminated with arousal was similar to those which terminated without arousal for both hypopnea events (27.6% ± 13.9%max vs 29.9% ± 15.9%max, P = ns) and apnea events (22.9% ± 11.5%max vs 22.1% ± 12.6%max, P = ns). The Pes at the end of respiratory events terminated with arousal was also similar to those terminated without arousal. There was a small but significant difference in EMGdi at the end of respiratory events between hypopnea and apnea (25.3% ± 14.2%max vs 21.7% ± 13.2%max, P < 0.05]. Our data do not support the concept that there is threshold of neural respiratory drive that is responsible for arousal in patients with obstructive sleep apnea.

Intermittent hypoxia in childhood: the harmful consequences versus potential benefits of therapeutic uses.

Intermittent hypoxia (IH) often occurs in early infancy in both preterm and term infants and especially at 36–44 weeks postmenstrual age. These episodes of IH could result from sleep-disordered breathing or may be temporally unrelated to apnea or bradycardia events. There are numerous reports indicating adverse effects of IH on development, behavior, academic achievement, and cognition in children with sleep apnea syndrome. It remains uncertain about the exact causative relationship between the neurocognitive and behavioral morbidities and IH and/or its associated sleep fragmentation. On the other hand, well-controlled and moderate IH conditioning/training has been used in sick children for treating their various forms of bronchial asthma, allergic dermatoses, autoimmune thyroiditis, cerebral palsy, and obesity. This review article provides an updated and impartial analysis on the currently available evidence in supporting either side of the seemingly contradictory scenarios. We wish to stimulate a comprehensive understanding of such a complex physiological phenomenon as intermittent hypoxia, which may be accompanied by other confounding factors (e.g., hypercapnia, polycythemia), in order to prevent or reduce its harmful consequences, while maximizing its potential utility as an effective therapeutic tool in pediatric patients.

Does Acute Physical Exercise Performed In Hypoxia Influence On The Index Of Apnea/ Hypopnea?

The events of apnea/ hypopnea are characterized by recurrent pauses in breathing during sleep, which can impair its quality. Studies show that physical exercise performed at sea level can be a good strategy to improve such events. However, in condition of hypoxia, little is known on the influence of exercise on the Index of apnea/ hypopnea. Purpose: To evaluate if, in condition of hypoxia, the index of apnea/ hypopnea is altered and if the acute physical exercise performed in this condition can influence this index. METHODS: Thirty-eight healthy men were included in the study, distributed randomly into four groups: Normoxia n=10, Hypoxia n=10, Exercise in Normoxia n=10 and Exercise in Hypoxia n=8. Sample characteristics were: age 23 ± 8 years, body mass 71 ± 7 kg, height 1.76 ± 0.6 m, BMI 22 ± 9 kg/ m2 and peak VO2 47 ± 4 ml/ kg/ min. Exposure to hypoxia began at 8:00 A.M. and lasted 24 hours in a simulator of altitude (Colorado Altitude Training ™ / CAT-12 Air Unit), equivalent to 4,500m. After 4 hours of exposure to hypoxia one session of physical exercise of 60 minutes at 50% of peak VO2 was performed. The indexes of apnea/ hypopnea were assessed by polysomnography from 22:00 P.M. to 8:00 A.M. Comparisons were made using ANOVA One Way. RESULTS: There was an increase in the index of apnea/ hypopnea (12.4 ± 1.2 vs. 0.7 ± 0.1per hour, p<0.05), apnea index (4.0 ± 1.3 vs. 1.3 ± 0.2per hour, p<0.05) and hypopnea index (8.9 ± 1.0 vs. 1.4 ± 0.5per hour, p<0.05) in the hypoxia group compared to normoxia group. However, no significant differences in the index of apnea/ hypopnea were observed, index apnea and index hypopnea of sleep in normoxia group vs. exercise in normoxia group and hypoxia group vs. exercise in hypoxia group. CONCLUSION: The condition of hypoxia increases the index of apnea/ hypopnea of sleep, similar to those with obstructive sleep apnea/hypopnea syndrome. Acute physical exercise performed in hypoxia condition does not reduce the index of apnea/ hypopnea generated by hypoxia. Thus, it is suggested that people with obstructive sleep apnea should avoid places of high altitude. The practice of acute physical exercise for healthy youth in these conditions was not efficient. Supported by FAPESP n ° 2012 / 09236-4

Coronary heart disease incidence in sleep disordered breathing: the Wisconsin Sleep Cohort Study.

The aim of the study was to determine the association of objectively measured sleep disordered breathing (SDB) with incident coronary heart disease (CHD) or heart failure (HF) in a nonclinical population. Longitudinal analysis of a community-dwelling cohort followed up to 24 y. Sleep laboratory at the Clinical Research Unit of the University of Wisconsin Hospital and Clinics. There were 1,131 adults who completed one or more overnight polysomnography studies, were free of CHD or HF at baseline, were not treated by continuous positive airway pressure (CPAP), and followed over 24 y. None. In-laboratory overnight polysomnography was used to assess SDB, defined by the apnea-hypopnea index (AHI) using apnea and hypopnea events per hour of sleep. Incident CHD or HF was defined by new reports of myocardial infarction, coronary revascularization procedures, congestive heart failure, and cardiovascular deaths. We used baseline AHI as the predictor variable in survival analysis models predicting CHD or HF incidence adjusted for traditional confounders. The incidence of CHD or HF was 10.9/1,000 person-years. The mean time to event was 11.2 ± 5.8 y. After adjusting for age, sex, body mass index, and smoking, estimated hazard ratios (95% confidence interval) of incident CHD or HF were 1.5 (0.9-2.6) for AHI > 0-5, 1.9 (1.05-3.5) for AHI 5 ≤ 15, 1.8 (0.85-4.0) for AHI 15 ≤ 30, and 2.6 (1.1-6.1) for AHI > 30 compared to AHI = 0 (P trend = 0.02). Participants with untreated severe sleep disordered breathing (AHI > 30) were 2.6 times more likely to have an incident coronary heart disease or heart failure compared to those without sleep disordered breathing. Our findings support the postulated adverse effects of sleep disordered breathing on coronary heart disease and heart failure.

Treatment of Snoring and Obstructive Apnea with Oral Appliance

Recently, oral appliances for treating snoring and obstructive sleep apnea are widely used. Among various appliances, mandibular advancement devices are most effective without serious side effects. Advancement of mandible keep airway open and decrease snoring and/or obstructive apnea events. They can be used as stand-alone therapy or an adjunct to continuous positive air pressure for lowering air pressure. Oral appliances should be applied by dentists who have knowledges and experiences on occlusion and temporomandibular disorders and manage of side effects.

Theories on possible temporal relationships between sleep bruxism and obstructive sleep apnea events. An expert opinion.

Sleep bruxism (SB) is a term covering different motor phenomena with various risk and etiological factors and potentially different clinical relevance, especially as far as its possible protective role against obstructive sleep apnea (OSA) is concerned. The present expert opinion discusses the possible temporal relationships between the two phenomena. Four hypothetical scenarios for a temporal relationship may be identified: (1) the two phenomena are unrelated; (2) the onset of the OSA event precedes the onset of the SB event within a limited time span, with SB having a potential OSA-protective role; (3) the onset of the SB event precedes the onset of the OSA event within a limited time span, with SB having an OSA-inducing effect; and (4) the onset of the OSA and SB event occurs at the same moment. Literature findings on the SB-OSA temporal relationship are inconclusive. The most plausible hypothesis is that the above scenarios are all actually possible and that the relative predominance of one specific sequence of events varies at the individual level. SB activity may be protective against OSA by protruding the mandible and restoring airway patency in those subjects who benefit from mandibular advancement strategies or may even be related to OSA induction, as a consequence of airways' mucosae swelling resulting from a SB-induced trigeminal cardiac reflex. Clinicians should keep in mind that the SB-OSA relationship is complex and that interindividual differences may explain the possible different SB-OSA relationships, with particular regard to the anatomical site of obstruction.

Characterization of sleep breathing pattern in patients with type 2 diabetes: sweet sleep study.

BackgroundAlthough sleep apnea-hypopnea syndrome (SAHS) is highly prevalent in patients with type 2 diabetes (T2D), it is unknown whether or not subjects with and without T2D share the same sleep breathing pattern.Methodology/Principal findingsA cross-sectional study in patients with SAHS according to the presence (n = 132) or not (n = 264) of T2D. Both groups were matched by age, gender, BMI, and waist and neck circumferences. A subgroup of 125 subjects was also matched by AHI. The exclusion criteria included chronic respiratory disease, alcohol abuse, use of sedatives, and heart failure. A higher apnea hypopnea index (AHI) was observed in T2D patients [32.2 (10.2–114.0) vs. 25.6 (10.2–123.4) events/hours; p = 0.002). When sleep events were evaluated separately, patients with T2D showed a significant increase in apnea events [8.4 (0.1–87.7) vs. 6.3 (0.0–105.6) e/h; p = 0.044), as well as a two-fold increase in the percentage of time spent with oxygen saturation <90% [15.7 (0.0–97.0) vs. 7.9 (0.0–95.6) %; <0.001)], higher rates of oxygen desaturation events, and also higher daily sleepiness [7.0 (0.0–21.0) vs. 5.0 (0.0–21.0); p = 0.006)] than subjects without T2D. Significant positive correlations between fasting plasma glucose and AHI, the apnea events, and CT90 were observed. Finally, multiple linear regression analyses showed that T2D was independently associated with AHI (R2 = 0.217), the apnea index (R2 = 0.194), CT90 (R2 = 0.222), and desaturation events.Conclusions/significanceT2D patients present a different pattern of sleep breathing than subject without diabetes. The most important differences are the severity of hypoxemia and the number of apneas whereas the incidence of hypopnea episodes is similar.

An obstructive sleep apnea detection approach using kernel density classification based on single-lead electrocardiogram.

Obstructive sleep apnea (OSA) is a common sleep disorder that often remains undiagnosed, leading to an increased risk of developing cardiovascular diseases. Polysomnogram (PSG) is currently used as a golden standard for screening OSA. However, because it is time consuming, expensive and causes discomfort, alternative techniques based on a reduced set of physiological signals are proposed to solve this problem. This study proposes a convenient non-parametric kernel density-based approach for detection of OSA using single-lead electrocardiogram (ECG) recordings. Selected physiologically interpretable features are extracted from segmented RR intervals, which are obtained from ECG signals. These features are fed into the kernel density classifier to detect apnea event and bandwidths for density of each class (normal or apnea) are automatically chosen through an iterative bandwidth selection algorithm. To validate the proposed approach, RR intervals are extracted from ECG signals of 35 subjects obtained from a sleep apnea database ( http://physionet.org/cgi-bin/atm/ATM ). The results indicate that the kernel density classifier, with two features for apnea event detection, achieves a mean accuracy of 82.07 %, with mean sensitivity of 83.23 % and mean specificity of 80.24 %. Compared with other existing methods, the proposed kernel density approach achieves a comparably good performance but by using fewer features without significantly losing discriminant power, which indicates that it could be widely used for home-based screening or diagnosis of OSA.

Application of the Permutation Entropy over the Heart Rate Variability for the Improvement of Electrocardiogram-based Sleep Breathing Pause Detection

In this paper the permutation entropy (PE) obtained from heart rate variability (HRV) is analyzed in a statistical model. In this model we also integrate other feature extraction techniques, the cepstrum coefficients derived from the same HRV and a set of band powers obtained from the electrocardiogram derived respiratory (EDR) signal. The aim of the model is detecting obstructive sleep apnea (OSA) events. For this purpose, we apply two statistical classification methods: Logistic Regression (LR) and Quadratic Discriminant Analysis (QDA). For testing the models we use seventy ECG recordings from the Physionet database which are divided into equal-size learning and testing sets. Both sets consist of 35 recordings, each containing a single ECG signal. In our experiments we have found that the features extracted from the EDR signal present a sensitivity of 65.6% and specificity of 87.7% (auc = 85) in the LR classifier, and sensitivity of 59.4% and specificity of 90.3% (auc = 83.9) in the QDA classifier. The HRV-based cepstrum coefficients present a sensitivity of 63.8% and specificity of 89.2% (auc = 86) in the LR classifier, and sensitivity of 67.2% and specificity of 86.8% (auc = 86.9) in the QDA. Subsequent tests show that the contribution of the permutation entropy increases the performance of the classifiers, implying that the complexity of RR interval time series play an important role in the breathing pauses detection. Particularly, when all features are jointly used, the quantification task reaches a sensitivity of 71.9% and specificity of 92.1% (auc = 90.3) for LR. Similarly, for QDA the sensitivity is 75.1% and the specificity is 90.5% (auc = 91.7).

Relationship between severity of obstructive sleep apnea and adverse cardiac outcomes in non-diabetic patients presenting with myocardial infarction.

Previous studies that have reported an association between obstructive sleep apnea and adverse cardiac events were confounded by a high prevalence of diabetes mellitus. We investigated the relationship between obstructive sleep apnea and the occurrence of major adverse cardiac events in non-diabetic patients who presented with ST-segment elevation myocardial infarction. A total of 41 patients who underwent overnight sleep screening within 5 days after admission for myocardial infarction from January 2007 to December 2008 were identified. Major adverse cardiac events-defined as a composite of cardiac death, non-fatal myocardial infarction, hospitalization for angina and congestive heart failure at 5-year follow-up-were determined. The patients were divided into two groups: those who experienced major adverse cardiac events and those who did not. In the overall cohort, the prevalence of obesity was 4.9 %. A total of 13 (31.7 %) patients had major adverse cardiac events. The mean apnea-hypopnea index was 25.4 ± 20.3. The group that experienced major adverse cardiac events had a higher apnea-hypopnea index than the group that did not (36.1 ± 21.0 vs 20.4 ± 18.2; P = 0.016). After adjusting for the resolution of ST-segment elevation and the use of a glycoprotein IIb/IIIa inhibitor, logistic regression analysis revealed that the apnea-hypopnea index remained an independent predictor of major adverse cardiac events (odds ratio 1.044; 95 % confidence interval 1.003-1.086; P = 0.033). In non-diabetic patients, the severity of obstructive sleep apnea was associated with the occurrence of major adverse cardiac events at 5-year follow-up after ST-segment elevation myocardial infarction.

Oropharyngeal suctioning in neonates immediately after delivery: Influence on cerebral and peripheral tissue oxygenation

BackgroundRoutine oropharyngeal suctioning in term vigorous neonates immediately after birth is a questionable practice. Current recommendations favor suctioning only in the presence of considerable obstruction due to secretions, blood or other matter. We aimed to analyze the influence of oropharyngeal suctioning on cerebral and peripheral muscle oxygenation in term neonates during transition immediately after birth. MethodsWe included term neonates after elective cesarean section for this prospective observational study. Oropharyngeal suctioning was performed based on the clinicians' judgment of threatening airway obstruction. From a total of 138 enrolled neonates, 36 were suctioned and then compared to 36 controls matched for gestational age. Heart rate (HR) and pre/postductal arterial oxygen saturation (SpO2pre/SpO2post) were measured by pulse oximetry. Cerebral (rSO2brain) and pre/postductal peripheral muscle tissue oxygenation (rSO2pre/rSO2post) were measured by near infrared spectroscopy during the first 15min of life. ResultsAll neonates in both groups experienced normal postnatal transition with normal Apgar scores (Apgar 9/10/10) and with no events of apnea or bradycardia induced by suctioning. SpO2pre values were slightly lower at 2 and 4min after birth. Suctioning had no main and interaction effect on HR, SpO2post, rSO2brain, rSO2pre and rSO2post in the first 15min after birth. ConclusionIn the present study we were able to show that, in term neonates, when correctly indicated, immediate postnatal oropharyngeal suctioning does not compromise cerebral and peripheral muscle tissue oxygenation. However, any suction maneuver must be performed with caution and strict indication during neonatal transition.

Unbound Unconjugated Hyperbilirubinemia Is Associated with Central Apnea in Premature Infants

To evaluate whether jaundice, indexed by unbound bilirubin (UB), is associated with central apnea in premature infants. A prospective observational study was performed with 27-33 weeks' gestational age infants who were not requiring either mechanical ventilation or noninvasive ventilation with continuous positive airway pressure beyond 24 hours after birth. Infants with congenital infections, chromosomal disorders, craniofacial anomalies, and/or family history of hearing loss were excluded. Total serum bilirubin and UB were measured twice daily during the first postnatal week and then when clinically indicated. Central apnea was evaluated by visual inspection of continuous, electronic cardiorespiratory recordings until 2 weeks of age. One hundred infants were subdivided into 2 groups via median peak UB level: the high UB group (greater than median) and low UB group (less than median). The high UB group had an increased frequency of apnea events during the first 2 weeks compared with infants in the low UB group. After we controlled for confounders, the high UB group had more events of apnea during the first 2 postnatal weeks compared with the low UB group (incidence rate ratio: 1.9, 95% CI 1.2-3.2). Our findings suggest that jaundice, as indexed by UB, is associated with central apnea in premature infants.