Oxygen saturation during the first 24 hours of life

AIM: To determine normative data for arterial oxygen saturation, measured by pulse oximetry (SpO2), in healthy full term infants throughout their first 24 hours of life. METHODS: Long term recordings of SpO2, pulse waveform, and breathing movements were made on 90 infants. Recordings were analysed for baseline SpO(2), episodes of desaturation (SpO2 /= four seconds, and periodic apnoea (>/= three apnoeic pauses, each separated by /= 20 seconds) were identified in six recordings. Four desaturations fell to 相似文献   

Blood transfusion in anemic infants with apnea of prematurity

We found recently that blood transfusions had no effect on bradycardia and hypoxemia, the clinically important components of apnea of prematurity, in mildly anemic infants. Here, we wanted to know whether this also holds true for more severely anemic patients. Nineteen preterm infants, median gestational age at birth 25 (range 22-30) weeks, age at the time of study 5.5 (range 1-13) weeks, for whom a blood transfusion was ordered because of recurrent episodes of bradycardia and/or hypoxemia in conjunction with anemia (median hemoglobin level 78 g/l, range 63-98 g/l) were investigated. One infant received two transfusions and was thus studied twice. 4-hour recordings of pulse oximeter saturation (SpO(2)), pulse waveforms, electrocardiogram, breathing movements, and nasal airflow were performed immediately before transfusion of 20 ml/kg packed red blood cells and again 24 h later. The recordings were analyzed for baseline heart and respiratory rates and SpO(2), all measured during regular breathing, as well as for apnea (>/=20 s), bradycardia (heart rate <2/3 of baseline for >/=4 s), and episodic desaturation (SpO(2) /=4 s). There was no significant change in the combined frequency of bradycardia and desaturation, the primary study end point - median 6.4/h (range 3.0-13.5/h) before versus 4.6/h (range 0.6-15.7/h) after transfusion -, although there was slightly less bradycardia - 0.8/h (range 0.0-8.8/h) versus 0.7/h (range 0.0-5.1/h; p < 0.05). Baseline heart and respiratory rates decreased, respectively, from 163/min (range 140-182/min) and 58/min (range 34-98/min) to 152/min (range 134-172/min) and 55/min (range 36-82/min; p < 0.01). We conclude that blood transfusions significantly reduced heart and respiratory rates in these anemic infants, but had little effect on apnea of prematurity.     

New desaturation index to evaluate neonatal apnea using polygraphy

BACKGROUND: Polygraph recordings of neonatal apnea obtained using an Eden Trace II monitor were manually analyzed to devise a new desaturation index (DSI). METHODS: Heart rate, thoracic respiratory movements, airflow, and blood oxygen saturation (SpO2) of 25 neonates in intensive care were monitored using polygraphy. The DSI was defined as the number of SpO2 decreases per hour of valid monitoring time. Neonates were divided into three groups according to DSI85: group A, DSI85 less than one decrease per hour (n = 12); group B, DSI85 ranging from one to nine decreases per hour (n = 8); and group C, DSI85 > or=10 decreases per hour (n = 5). Clinical characteristics and type of apnea in each group were compared statistically. Group C neonates were treated with aminophylline, and the effects of treatment were evaluated. RESULTS: Gestational age at birth, birthweight, age at monitoring and valid monitoring time did not differ significantly between the three groups, but mean SpO2, DSI70, the frequency of central apnea and periodic breathing did. Oxygen desaturation in group B and particularly group C was predominantly attributable to periodic breathing rather than central apnea. Aminophylline produced significant improvement in periodic breathing but exerted no significant effect on the other types of apnea. Both DSI85 and DSI70 were strongly correlated (r = 0.833). CONCLUSIONS: Polygraphic study of neonates at risk revealed marked arterial oxygen desaturation, even among those with periodic breathing. This novel DSI represents a useful tool for evaluating apnea and periodic breathing in neonates and for assessing treatment efficacy.     

Relationship between functional residual capacity and oxygen desaturation during short central apneic events during sleep in "late preterm" infants

Apneic episodes are frequent in the preterm neonate and particularly in active sleep (AS), when functional residual capacity (FRC) can be decreased. Furthermore, FRC may be inversely correlated with the speed of blood-O(2)-desaturation. We evaluated the potential involvement of FRC in the mechanisms responsible for blood-O(2)-desaturation during short central apneic events (>3 s) in "late-preterm" infants and analyzed the specific influence of sleep state. Apneic events were scored in 29 neonates (postmenstrual age: 36.1 +/- 1.2 wk) during AS and quiet sleep (QS). FRC was measured during well-established periods of regular breathing. Apneas with blood-O(2)-desaturation (drop in SpO(2) >5% from the baseline, lowest SpO(2) during apnea: 91.4 +/- 1.8%) were more frequent in AS than in QS, whereas no difference was seen for apneas without desaturation. The magnitude of the FRC did not depend on the sleep state. In AS only, there was a negative relationship between FRC and the proportion of apneas with desaturation. Even in late preterm infants who do not experience long-lasting apnea, blood-O(2)-desaturation during short apneic events is related (in AS but not QS) to a low baseline FRC. Sleep stage differences argue for a major role of AS-related mechanisms in the occurrence of these apneas.     

Oxygen saturation trends immediately after birth

OBJECTIVE: To describe the changes in oxygen saturation (SpO2) in healthy infants during the first 10 minutes of life. STUDY DESIGN: In this observational study, infants > or = 35 weeks gestation at birth who did not require supplemental oxygen had continuous recordings taken of the preductal SpO2 over the first 10 minutes of life. RESULTS: A total of 115 infants were analyzed. On average, infants delivered by cesarean delivery had a 3% lower SpO2 than infants delivered by vaginal delivery (95% confidence interval [CI] = -5.8 to -0.7; P = .01). Infants born by cesarean delivery also took longer (risk ratio, 1.79) to reach a stable SpO2 > or = 85% (95% CI = 1.02 to 3.14; P = .04). At 5 minutes of age, median SpO2 values (interquartile range) were 87% (80% to 95%) for infants delivered vaginally and 81% (75% to 83%) for those delivered through cesarean section. The median SpO2 did not reach 90% until 8 minutes of age in either group. CONCLUSIONS: The process of transitioning to a normal postnatal oxygen saturation requires more than 5 minutes in healthy newborns breathing room air.     

Periodic breathing and apnea in preterm infants

The relationship between periodic breathing and idiopathic apnea of prematurity was investigated. We recorded respiratory impedance, heart rate, pulse oximetry and end-tidal CO2 from 68 untreated infants of less than or equal to 34 wk gestation with a diagnosis of idiopathic apnea of prematurity. Mean birth wt was 1476 g (SD 420) and mean gestational age was 29.9 wk (SD 2.6). Apneas of more than 15 s duration that were associated with hypoxemia or bradycardia were identified by semiautomated analysis of computerized records. A total of 1116 significant apneic spells were identified, only one of which occurred during an epoch of periodic breathing, five others occurred within 2 min of the end of an epoch of periodic breathing. Less than 0.6% of significant apneic spells occur within 2 min of periodic breathing. In all of the 12 infants that were monitored starting in the first 12 h of life, significant apneic spells were identified before 36 h of age and no precipitating factors were identified. Periodic breathing did not occur during the first 48 h of life, a finding that supports the concept that the peripheral chemoreceptor is inactive in the first 48 h of life. Periodic breathing in the premature infant is not a precursor to significant apnea.     

Mixed and obstructive sleep apnea and near miss for sudden infant death syndrome: 2. Comparison of near miss and normal control infants by age.

Twenty-nine full-term near miss for sudden infant death syndrome (SIDS) and 30 normal control infants underwent 24-hour polygraphic monitoring. Several types of respiratory events during sleep (eg, central, mixed, and obstructive apnea, periodic breathing) were defined and tabulated. Analysis of these respiratory variables and comparison of groups of near miss and control infants indicated that between 3 weeks and 4 1/2 months of age only one variable was consistently different at a statistically significant level: the number of mixed and obstructive apnea greater than 3 seconds during total sleep time. This study also showed an increase in mixed and obstructive respiratory events during sleep at 6 weeks of age in control as well as in near miss infants.     

Infant sleep apnea profile: preterm vs. term infants

By means of polygraphic sleep recording, the sleep apnea profile with respect to the number and duration of inactive, obstructive and mixed apneic episodes as well as periodic breathing has been investigated in infants born preterm at 40, 52 and 64 weeks conceptional age and compared to that of term infants. At 40 weeks preterm infants showed significantly more apnea and periodic breathing compared to term infants. The difference was essentially due to obstructive and mixed apnea in non-REM sleep.There was a sharp decrease in all apneic variables—inactive, obstructive and mixed apnea as well as of periodic breathing—at 52 weeks conceptional age in infants that were previously preterm. Both groups exhibited a rather identical sleep apnea profile at 64 weeks. Two prospectively studied infants in the preterm group later became SIDS victims. One of them might have been identified as being at risk on the basis of his apnea profile compared to the normative data now available.Abbreviations REM rapid eye movements     

Oxygen saturation and breathing patterns in infancy. 1: Full term infants in the second month of life.

Overnight 12 hour tape recordings were made of arterial oxygen saturation (SaO2, pulse oximeter in the beat to beat mode) and abdominal wall breathing movement on 67 healthy, full term infants between the ages of 29 and 54 (median 39) days. The median baseline SaO2 during regular breathing was 99.8% (range 97.0-100%). Fifty four infants (81%) had shortlived episodes during which SaO2 fell to 80% or less (desaturation); the median rate was 0.9 desaturations/hour, and the median duration of each desaturation was 1.2 seconds. The 97th centile value for the duration of all episodes in which SaO2 fell to less than or equal to 80% was 4.0 seconds. The frequency of desaturations was significantly higher, and their duration significantly longer, when the breathing pattern was non-regular rather than regular. The percentage of apnoeic pauses (greater than or equal to 4 seconds in duration) followed by a desaturation was higher during non-regular than regular breathing; it was particularly high during periodic breathing. A knowledge of normal variability of baseline measurements of oxygenation and of the relationship between oxygenation and breathing patterns in infants is essential to the use of pulse oximetry in clinical practice.     

Screening of subsequent siblings of children who die of sudden infant death syndrome

Since the value of home apnea monitoring for subsequent siblings (subsibs) of an infant who died of sudden infant death syndrome is uncertain, we describe an evaluation and monitoring program for subsibs. Eighty subsibs were screened in hospital at an average age of 4.6 weeks. The most valuable investigations included history, physical examination, blood gas tests, and four days on an apnea monitor in hospital. Sleep recordings added no decision-making data. Only 23 infants met one of the following criteria for home apnea monitoring: (1) sleep apnea for more than 15 s (either on sleep recording or recognized by apnea alarm), (2) more than 4.5 episodes of apnea per hour of sleep, (3) periodic breathing greater than 24% of sleep time, or (4) severe parental anxiety. Twenty-two infants were monitored until they were aged 6 months and had spent two months apnea free. Twelve had apnea at home. All of the infants survived. Excessive periodic breathing alone did not seem to be a valid reason for home monitoring. Our screening program is simple, acceptable to families, and useful to select a smaller number of subsibs for home apnea monitoring.     

Assessing clinical significance of apnea exceeding fifteen seconds with event recording

Using event recording, we determined how often apnea exceeding 15 seconds in duration was associated with bradycardia and how often patients with apnea resumed breathing spontaneously. Of 1306 documented apnea events exceeding 15 seconds (54 patients), 926 lasted 16 to 20 seconds, 262 lasted 21 to 25 seconds, and 118 exceeded 25 seconds. Of these episodes, 75.3% were isolated and 14.9% were associated with pulse deceleration, 4.4% with irregular transthoracic impedance, and 5.4% with bradycardia. Event recording provided data supporting discontinuation of monitoring in 50 of 54 patients: 36 spontaneously resumed breathing before the auditory alarm and 14 had a decreased incidence of apnea with maturation. Follow-up of 51 patients (three not located) showed that none had subsequent apparent life-threatening events or sudden infant death syndrome. Our results in these older infants and children (median age 6.7 months) provide substantiation that such patients with apnea of less than 20 seconds without bradycardia do not require continued monitoring. Further, these data suggest that in selected older infants, longer isolated apnea may be well tolerated; however, hemoglobin saturation during sleep and the ability to resume breathing after the apnea alarm delay is prolonged should be verified. Our patient population had a wide age range and heterogeneity of diagnoses, and was typically free of symptoms, so these results should not be extrapolated uncritically to premature infants, infants with chronic lung disease, and patients with symptomatic apnea.     

Low daytime pulse oximetry reading is associated with nocturnal desaturation and obstructive sleep apnea in children with sickle cell anemia

A retrospective medical record review was established to test the hypothesis that in children with sickle cell anemia (SCA), a daytime oxygen saturation (SpO(2)) 相似文献   

Naloxone does not alter the arousal response decrement after repeated exposure to hypoxemia during sleep in lambs.

Experiments were done to determine if endogenous opiates cause the arousal response decrement that follows repeated exposure to hypoxemia during sleep in lambs. Five lambs were anesthetized and instrumented for sleep staging and measurement of arterial Hb oxygen saturation. No sooner than 3 d after surgery, measurements were made in quiet sleep and active sleep during control periods when the lambs were breathing 21% oxygen and during experimental periods when the lambs were breathing 5% oxygen. The experimental period was terminated during each epoch by changing the inspired gas mixture back to 21% oxygen, once the lamb aroused from sleep. After each lamb had been exposed to 5% oxygen during 100 consecutive epochs of sleep, naloxone--an opiate antagonist--was given i.v. in a dose of 3 mg/kg as a bolus. The animals continued to be exposed to 5% oxygen during six more epochs of sleep after the administration of naloxone. Arousal occurred from both sleep states during rapidly developing hypoxemia but was delayed in active sleep compared to quiet sleep. The arterial Hb oxygen saturation at arousal was significantly lower, and the time to arousal was significantly longer with repeated exposure to hypoxemia during both quiet sleep and active sleep. Naloxone did not alter this arousal response decrement to hypoxemia. Thus, our data provide evidence that endogenous opiates do not play a major role in causing the arousal response decrement that follows repeated exposure to hypoxemia during sleep in lambs.     

Tachypnoea is a good predictor of hypoxia in acutely ill infants under 2 months.

OBJECTIVE: To evaluate the respiratory rate as an indicator of hypoxia in infants < 2 months of age. SETTING: Pediatric emergency unit of an urban teaching hospital. SUBJECTS: 200 infants < 2 months, with symptom(s) of any acute illness. METHODS: Respiratory rate (by observation method), and oxygen saturation (SaO(2)) by means of a pulse oximeter were recorded at admission. Infants were categorised by presence or absence of hypoxia (SaO(2) /= 50/min in 120 (60%), >/= 60/min in 101 (50. 5%), and >/= 70/min in 58 (29%) infants. Hypoxia (SaO(2) /= 60/min predicted hypoxia with 80% sensitivity and 68% specificity. CONCLUSION: These results indicates that a respiratory rate > 60/min is a good predictor of hypoxia in infants under 2 months of age brought to the emergency service of an urban hospital for any symptom(s) of acute illness.     

Are polygraphic and cardiopneumographic respiratory patterns useful tools for predicting the risk for sudden infant death syndrome? A 10-year study

Between 1974 and 1984 we have studied 204 control infants (C) comparing them with 650 SIDS siblings (SS) and 146 near-miss for SIDS (NM). These 1,000 full-term infants were recorded by day polysomnography (DPSG; n = 417), night polysomnography (NPSG; n = 257) and cardiopneumography (CPG; n = 2,600). Records were visually analyzed. In DPSG and NPSG, total amount of central, mixed and obstructive apnea as well as the percentage of periodic breathing was studied in each sleep state (active sleep, AS; quiet sleep, QS; indeterminate sleep, IS, and total sleep, TS) and over the total recording time (TRT). In CPG, only the total amount of central apnea and percentage of periodic breathing over TRT were studied. Infants were grouped according to postnatal age: less than 5, greater than or equal to 5 to less than or equal to 13, and greater than 13 to less than or equal to 26 weeks. In each age group results were compared as follows: C vs. SS, C vs. NM, and SS vs. NM for each parameter studied. Before 5 weeks and after 13 weeks there was no significant difference between C and SS, C and NM, and SS and NM in DPSG and NPSG for all categories of central, mixed and obstructive apnea as well as the percentage of periodic breathing in different sleep states and over TRT. Similar results were obtained in CPG for all categories of central apnea and percentage of periodic breathing over TRT.(ABSTRACT TRUNCATED AT 250 WORDS)     

Skin-to-skin (kangaroo) care, respiratory control, and thermoregulation

AIM: To demonstrate that skin-to-skin care (SSC) has no detrimental effects on the frequency of episodes of bradycardia and/or hypoxemia. METHODS: Twenty-two spontaneously breathing preterm infants (median gestational age at birth, 29 weeks [range, 24-31 weeks]; age at study, 26 days [range, 7-72 days]; weight at study, 1310 g [range, 725-1890 g]) had three 2-hour recordings of breathing movements, nasal airflow, heart rate, and oxygen saturation as measured by pulse oximetry (SpO(2)) before, during, and after SSC. Rectal temperature was obtained every 2 hours. Recordings were analyzed for baseline heart and respiratory rates, bradycardia (heart rate < two thirds of baseline), and hypoxemia (SpO(2) < or =80%), as well as for breathing pattern (regular vs non-regular). RESULTS: Baseline heart rate and respiratory rate increased during SSC (P <.01), as did the combined frequency of bradycardia and hypoxemia (from 1.5/h [0-8] before to 2.8/h [0-15] during SSC; P<.05). Rectal temperature increased from 36.9 degrees C (36.2 degrees -37.4 degrees C) to 37.3 degrees C (36.6 degrees -38.6 degrees C; P <.01). The proportion of regular breathing pattern decreased from 14% (2%-28%) to 7% (3%-26%) with SSC (P<.01). CONCLUSION: SSC was associated with a significant increase in the combined frequency of bradycardia and hypoxemia and with less regular breathing. These changes were unexpected and may have been related to heat stress. Body temperature, heart rate, and oxygenation should be monitored during SSC.     

Bradycardia and desaturation during skin-to-skin care: no relationship to hyperthermia

OBJECTIVE: We recently found increased temperature and increased bradycardia and desaturation during skin-to-skin care (SSC). We wanted to determine if these effects were related. STUDY DESIGN: Twenty-two infants (median gestational age at birth 28.5 weeks [range 24-31], median age at study 25.5 days [range 10-60 days], median birth weight 1025 g [range 550-1525 g], median weight at study 1320 g [range 900-2460 g]) underwent three 2-hour recordings of breathing movements, nasal airflow, heart rate, and pulse oximeter saturation (SpO 2 ): at thermoneutrality (TN) during incubator care, at TN during SSC, and at elevated temperature (ET) during incubator care. Core temperature was measured via a rectal probe. Recordings were analyzed for the summed rate of bradycardia and desaturation (heart rate <2/3 of baseline; SpO 2 相似文献   

Progressive shortening of the periodic breathing cycle duration in normal infants

Ten normal full-term neonates were monitored by oxycardiorespirography in hospital during the 1st wk of life, and subsequently at home at 4, 8, and 12 wk of age in a longitudinal study of the duration of the periodic breathing cycle during spontaneous sleep. Periodic breathing was observed in 25 of the 40 studies, with a total of 168 epochs of periodicity noted. Eighty-four percent of the periodic epochs occurring during nonrapid eye movements were preceded by a sigh, body movements, or sleep state transition, compared with 41% during rapid eye movements (p less than 0.005). There was a progressive reduction in the periodic breathing cycle duration, which fell significantly between the 1st and 4th wk, in both sleep states, (p less than 0.001). There was a further significant fall between 4 and 12 wk in nonrapid eye movement sleep (p less than 0.05), and there was no significant difference between sleep states at any postnatal age. The overall change in the duration of the periodic cycle, for both sleep states combined, was from 15.0 +/- 3.6 s at less than 1 wk to 12.4 +/- 1.8 s at 12 wk of age. The periodic breathing cycle duration progressively shortens over the first 3 months of life. We postulate that this shortening may be useful indicator of peripheral chemoreceptor maturation over this time period.     

Breathing patterns and heart rates at ages 6 weeks and 2 years.

Forty-two randomly selected, full-term, healthy infants underwent 24-hour electrocardiographic recordings and breathing movements at about ages 6 weeks (median age, 43 days; range, 34 to 61 days) and 2 years (median age, 26 months; range, 21 to 35 months). The number and duration of apneic pauses of 3.6 seconds or longer were analyzed. Periodic apnea was defined as a sequence of three or more apneic pauses, each separated by fewer than 20 breaths. All other apneic pauses were defined as isolated. Median heart rates and respiratory rates, which were measured during regular breathing, decreased from 137/min and 35/min to 98/min and 21/min, respectively. The total duration of periodic apnea remained unchanged (median, 0.06 min/h vs 0.05 min/h). Although the median frequency of all isolated apneic pauses decreased from 3.6/h to 2.5/h, the number of those that were longer than 6 seconds increased from 0.37/h to 0.80/h, leading to an increase in the proportion of these pauses, among all isolated apneic pauses, from 10% at age 6 weeks to 32% at age 2 years. Only one apneic pause in one infant at age 6 weeks, but eight pauses in six children at age 2 years, were longer than 15 seconds. A knowledge of such normal variability in the duration of apneic pauses in older infants and young children is essential for the interpretation of pneumograms and alarms while monitoring breathing movements.     

Ventilatory pattern following diphtheria-tetanus-pertussis immunization in infants at risk for sudden infant death syndrome

To evaluate the effects of diphtheria-tetanus-pertussis (DTP) immunization on the ventilatory pattern during sleep in infants at increased risk for sudden infant death syndrome (SIDS), we performed overnight pneumograms (recordings of ventilatory pattern and electrocardiogram) on 30 control infants, 46 infants with unexplained apnea, and 33 subsequent siblings of SIDS victims the night before and the night following a DTP immunization. Pneumograms were quantitated for total sleep time, longest apnea (in seconds), total duration of apneas longer than 6 s (in minutes), and total periodic breathing (in minutes). Following the DTP immunization there was no significant change in any criterion quantitated on pneumograms from any group except for a decrease in periodic breathing in the unexplained apnea group. We conclude that DTP immunization does not increase abnormalities of the ventilatory pattern as recorded by the pneumogram technique in infants at increased risk for SIDS.