Measurement of the CO2 apneic threshold in newborn infants: possible relevance for periodic breathing and apnea

2005 ◽  
Vol 98 (4) ◽  
pp. 1171-1176 ◽  
Author(s):  
Akram Khan ◽  
Mansour Qurashi ◽  
Kim Kwiatkowski ◽  
Don Cates ◽  
Henrique Rigatto
Keyword(s):  
Control System ◽  
Confidence Interval ◽  
Preterm Infants ◽  
Newborn Infants ◽  
Respiratory Control ◽  
Periodic Breathing ◽  
Term Infants ◽  
Nonsignificant Increase ◽  
A Minor

We measured the Pco2 apneic threshold in preterm and term infants. We hypothesized that, compared with adult subjects, the Pco2 apneic threshold in neonates is very close to the eupneic Pco2, likely facilitating the appearance of periodic breathing and apnea. In contrast with adults, who need to be artificially hyperventilated to switch from regular to periodic breathing, neonates do this spontaneously. We therefore measured the apneic threshold as the average alveolar Pco2 (PaCO2) of the last three breaths of regular breathing preceding the first apnea of an epoch of periodic breathing. We also measured the PaCO2 of the first three breaths of regular breathing after the last apnea of the same periodic breathing epoch. In preterm infants, eupneic PaCO2 was 38.6 ± 1.4 Torr, the preperiodic PaCO2 apneic threshold was 37.3 ± 1.4 Torr, and the postperiodic PaCO2 was 37.2 ± 1.4 Torr. In term infants, the eupneic PaCO2 was 39.7 ± 1.1 Torr, the preperiodic PaCO2 apneic threshold was 38.7 ± 1.0 Torr, and the postperiodic value was 37.9 ± 1.2 Torr. This means that the PaCO2 apneic thresholds were 1.3 ± 0.1 and 1.0 ± 0.2 Torr below eupneic PaCO2 in preterm and term infants, respectively. The transition from eupneic PaCO2 to PaCO2 apneic threshold preceding periodic breathing was accompanied by a minor and nonsignificant increase in ventilation, primarily related to a slight increase in frequency. The findings suggest that neonates breathe very close to their Pco2 apneic threshold, the overall average eupneic Pco2 being only 1.15 ± 0.2 Torr (0.95–1.79, 95% confidence interval) above the apneic threshold. This value is much lower than that reported for adult subjects (3.5 ± 0.4 Torr). We speculate that this closeness of eupneic and apneic Pco2 thresholds confers great vulnerability to the respiratory control system in neonates, because minor oscillations in breathing may bring eupneic Pco2 below threshold, causing apnea.

scholarly journals Delivery Room Management of Asphyxiated Term and Near-Term Infants

Neonatology ◽  
2021 ◽  
pp. 1-13
Author(s):  
Marlies Bruckner ◽  
Gianluca Lista ◽  
Ola D. Saugstad ◽  
Georg M. Schmölzer
Keyword(s):  
Preterm Infants ◽  
Newborn Infants ◽  
Neonatal Resuscitation ◽  
Birth Asphyxia ◽  
Delivery Room ◽  
Temperature Management ◽  
Term Infants ◽  
Term Newborn ◽  
Resuscitation Guidelines ◽  
Delivery Room Management

Approximately 800,000 newborns die annually due to birth asphyxia. The resuscitation of asphyxiated term newly born infants often occurs unexpected and is challenging for healthcare providers as it demands experience and knowledge in neonatal resuscitation. Current neonatal resuscitation guidelines often focus on resuscitation of extremely and/or very preterm infants; however, the recommendations for asphyxiated term newborn infants differ in some aspects to those for preterm infants (i.e., respiratory support, supplemental oxygen, and temperature management). Since the update of the neonatal resuscitation guidelines in 2015, several studies examining various resuscitation approaches to improve the outcome of asphyxiated infants have been published. In this review, we discuss current recommendations and recent findings and provide an overview of delivery room management of asphyxiated term newborn infants.

Periodic Breathing in Preterm Infants: Incidence and Characteristics

PEDIATRICS ◽  
1989 ◽  
Vol 84 (5) ◽  
pp. 785-792
Author(s):  
S. F. Glotzbach ◽  
R. B. Baldwin ◽  
N. E. Lederer ◽  
P. A. Tansey ◽  
R. L. Ariagno
Keyword(s):  
Preterm Infants ◽  
Age Groups ◽  
Periodic Breathing ◽  
Sudden Infant Death ◽  
Respiratory Pattern ◽  
Sudden Infant ◽  
Quiet Time ◽  
Term Infants ◽  
Respiratory Dysfunction ◽  
Postconceptional Age

The prevalence and characteristics of periodic breathing in preterm infants were measured by 24-hour impedance pneumograms in 66 preterm infants before discharge from the nursery. Four periodic breathing parameters (percentage of periodic breathing per quiet time, number of episodes of periodic breathing per 100 minutes of quiet time, mean duration of periodic breathing, and longest episode of periodic breathing) were compared to data available from healthy term infants and from term infants who subsequently died of sudden infant death syndrome (SIDS). Periodic breathing was found in all preterm infants studied and mean periodic breathing parameter values (12.0%, 8.6 episodes, 1.2 minutes, and 7.3 minutes, respectively) in our preterm population were substantially higher than values from healthy term infants and SIDS victims. Most periodic breathing parameters decreased significantly in infants studied at 39 to 41 weeks' postconceptional age compared with earlier postconceptional age groups. No relationship was found between central apneas of ≥15 seconds' duration and postconceptional age or any periodic breathing parameter. Periodic breathing is a common respiratory pattern in preterm infants that is usually not of pathologic significance. Associations between elevated levels of periodic breathing and respiratory dysfunction or SIDS should be made with caution.

Reduction in Obstructive Breathing Events During Body Rocking: A Controlled Polygraphic Study in Preterm and Full-Term Infants

PEDIATRICS ◽  
1995 ◽  
Vol 96 (1) ◽  
pp. 64-68
Author(s):  
J. Groswasser ◽  
M. Sottiaux ◽  
E. Rebuffat ◽  
T. Simon ◽  
M. Vandeweyer ◽  
...  
Keyword(s):  
Eye Movement ◽  
Preterm Infants ◽  
Upper Airway ◽  
Periodic Breathing ◽  
Full Term ◽  
Rapid Eye Movement ◽  
Term Infants ◽  
Obstructive Sleep ◽  
Significant Difference ◽  
Obstructive Sleep Apneas

Objective. To investigate the effect of body rocking on infant respiratory behavior during sleep. Methods. Eighteen infants with documented obstructive sleep apneas were studied. There were eight premature infants with persistent bradycardias and 10 infants born full-term, admitted after an idiopathic apparent life-threatening event. No cause for the obstructive apneas was found. The infants were recorded with polygraphic techniques during two successive nights. They were randomly assigned to a rocking or a nonrocking mattress. The conditions were reversed the following night, in a crossover design. Results. In both groups of infants, no significant difference was seen between the two consecutive nights for most of the variables studied: total sleep time, the proportion of non-rapid-eye-movement and rapid-eye-movement sleep, the number of arousals, the number and maximal duration of central apneas, the frequency of periodic breathing, the level of oxygen saturation, and heart rate. During the nonrocking nights, all infants had repeated obstructive breathing events. In seven of the eight preterm infants and in nine of the 10 full-term subjects, body rocking was associated with a significant decrease in the frequency of obstructive events. During rocking, in the preterm infants the obstructions fell from a median of 2.5 to 1.8 episodes per hour (P = .034). In the full-term infants, rocking reduced the obstructive events from a median of 1.5 obstructions per hour to 0.7 (P = .005). No difference was seen for the duration of the obstructive episodes. Conclusion. In preterm and full-term infants prone to obstructive sleep apneas, gentle side-to-side body rocking is associated with a significant decrease in the frequency of upper-airway obstructions.

Relative stability of human respiration during progressive hypoxia

1988 ◽  
Vol 65 (3) ◽  
pp. 1389-1399 ◽  
Author(s):  
D. W. Carley ◽  
D. C. Shannon
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Relative Stability ◽  
Respiratory Control ◽  
Periodic Breathing ◽  
Adult Males ◽  
Human Respiration ◽  
Progressive Hypoxia ◽  
The Mean ◽  
Breathing Room

We have systematically studied the relationship between the relative stability (R) of respiration and the loop gain (LG) of the CO2 control system in 15 healthy awake adult males during progressive hypoxia. R was measured by the ventilatory oscillations after brief (less than 10 s) CO2 challenges. Control theory suggests that such oscillations are completely governed by LG. A significant positive correlation was found between R and LG (r = 0.74, P less than 0.01, n = 85). A minimal mathematical model of respiratory control was used to predict R as a function of LG. Serial correlation analysis (r = 0.09, P greater than 0.1) of the residuals indicated statistical agreement between predictions and observations. The mean residual (0.011) was not significantly different from zero (P greater than 0.1). Also, as the model predicted, sustained periodic breathing (PB) occurred whenever the estimated LG was greater than unity. The mean LG breathing room air was 0.51 and for the 13 epochs of PB was 1.17 (range 0.71-1.65). It is concluded that PB is a quantitative extension of the relative stability continuum and corresponds to unstable operation of the CO2 control system. Furthermore, relative stability can be quantitatively predicted for each subject by a minimal mathematical model.

Possible mechanisms of periodic breathing during sleep

1988 ◽  
Vol 64 (3) ◽  
pp. 1000-1008 ◽  
Author(s):  
K. R. Chapman ◽  
E. N. Bruce ◽  
B. Gothe ◽  
N. S. Cherniack
Keyword(s):  
Control System ◽  
Respiratory Control ◽  
Periodic Breathing ◽  
Nrem Sleep ◽  
Loop Gain ◽  
Hypoxic Conditions ◽  
Spontaneous Oscillations ◽  
End Tidal ◽  
Arterial O2 Saturation ◽  
Stage 1

To determine the effect of respiratory control system loop gain on periodic breathing during sleep, 10 volunteers were studied during stage 1-2 non-rapid-eye-movement (NREM) sleep while breathing room air (room air control), while hypoxic (hypoxia control), and while wearing a tight-fitting mask that augmented control system gain by mechanically increasing the effect of ventilation on arterial O2 saturation (SaO2) (hypoxia increased gain). Ventilatory responses to progressive hypoxia at two steady-state end-tidal PCO2 levels and to progressive hypercapnia at two levels of oxygenation were measured during wakefulness as indexes of controller gain. Under increased gain conditions, five male subjects developed periodic breathing with recurrent cycles of hyperventilation and apnea; the remaining subjects had nonperiodic patterns of hyperventilation. Periodic breathers had greater ventilatory response slopes to hypercapnia under either hyperoxic or hypoxic conditions than nonperiodic breathers (2.98 ± 0.72 vs. 1.50 ± 0.39 l.min-1.Torr-1; 4.39 ± 2.05 vs. 1.72 ± 0.86 l.min-1.Torr-1; for both, P less than 0.04) and greater ventilatory responsiveness to hypoxia at a PCO2 of 46.5 Torr (2.07 ± 0.91 vs. 0.87 ± 0.38 l.min-1.% fall in SaO2(-1); P less than 0.04). To assess whether spontaneous oscillations in ventilation contributed to periodic breathing, power spectrum analysis was used to detect significant cyclic patterns in ventilation during NREM sleep. Oscillations occurred more frequently in periodic breathers, and hypercapnic responses were higher in subjects with oscillations than those without. The results suggest that spontaneous oscillations in ventilation are common during sleep and can be converted to periodic breathing with apnea when loop gain is increased.

FREQUENCY AND IMPLICATIONS OF SEVERE NEONATAL PROTEIN C DEFICIENCY

1987 ◽  
Author(s):  
M J Manco-Johnson ◽  
T C Abshire ◽  
L J Jacobson
Keyword(s):  
Preterm Infants ◽  
Protein C ◽  
Newborn Infants ◽  
Postnatal Life ◽  
Protein C Deficiency ◽  
Term Infants ◽  
Severe Respiratory Distress ◽  
Thrombotic Risk ◽  
Thrombin Activation ◽  
Low Levels

The newborn infant has a physiologically low level of protein C which rises very slowly in postnatal life. The frequency and significance of severe neonatal protein C deficiency has not been reported. In this study, protein C levels were measured in 110 newborn infants at the time of birth using functional (amidolytic, Cact) and immunologic (Laurell rocket, Cag) assays. The protein C levels were compared with a marker of thrombin activation (D-dimer fragment of fibrin, +D-D) and infants were subsequently followed for signs and symptoms of thrombosis. Results are summarized below (protein C levels are expressed as U/ml).Thirteen infants had protein C levels compatible with the homozygous deficiency state. Extremely low levels of protein C (<0.20 U/ml) were not found in well term infants and were rarely noted in stable preterm infants. D-D were infrequently present and no thrombosis occurred. Near term infants born with fetal distress frequently showed +D-D but rarely demonstrated extremely low levels of protein C. None of these infants required indwelling arterial catheters and no thromboses occurred. Preterm infants with severe respiratory distress showed lower protein C levels at birth (p <0.01). Although 71% had +D-D, thromboses in these infants were all related to invasive catheterizations. In contrast, the study population of twins demonstrated a high frequency of severe protein C deficiency with negative D-D and frequent thromboses, three of which occurred in the absence of instrumentation. In summary, severe protein C deficiency and thrombin activation are common in sick preterm infants with the risk of thrombosis increased by intravascular catheterization. In contrast, twins with severe protein C deficiency may manifest a thrombotic risk which is independent of thrombin activation or catheterization.

Acoustic Examination of Preterm and Full-Term Infant Cries

1999 ◽  
Vol 42 (4) ◽  
pp. 850-861 ◽  
Author(s):  
Alexander M. Goberman ◽  
Michael P. Robb
Keyword(s):  
Preterm Infants ◽  
Newborn Infants ◽  
Term Infant ◽  
Speech Development ◽  
Full Term ◽  
Spectral Energy ◽  
Term Infants ◽  
Average Spectrum ◽  
Long Time ◽  
Infant Cries

The acoustic characteristics of crying behavior displayed in 2 groups of newborn infants are reported. The crying episodes of 10 full-term and 10 preterm infants were audio recorded and analyzed with regard to the long-time average spectrum (LTAS) characteristics. An LTAS display was created for each infant's non-partitioned crying episode, as well as for 3 equidurational partitions of the crying episode. Measures of first spectral peak, mean spectral energy, and spectral tilt were revealing of differences between full-term and preterm infants' non-partitioned crying episodes. In addition, the full-term infants demonstrated significant changes in their crying behavior across partitions, whereas the preterm infants changed little across the crying episode. Discussion focuses on possible differences between full-term and preterm infants in their neurophysiological maturity, and the subsequent impact on their speech development. The importance of examining entire crying episodes when evaluating the crying behavior of infants is also discussed.

Maturation of respiratory control and the propensity for breathing instability in a sheep model

2009 ◽  
Vol 107 (5) ◽  
pp. 1463-1471 ◽  
Author(s):  
Bradley A. Edwards ◽  
Scott A. Sands ◽  
Elizabeth M. Skuza ◽  
Vojta Brodecky ◽  
Elaine M. Stockx ◽  
...  
Keyword(s):  
Control System ◽  
Steady State ◽  
Respiratory Control ◽  
Periodic Breathing ◽  
Loop Gain ◽  
Limited Evidence ◽  
Sheep Model ◽  
Ventilatory Responses ◽  
Gas Inhalation ◽  
Surrogate Measures

Limited evidence suggests that the ventilatory interaction between O2 and CO2 is additive after birth and becomes multiplicative with postnatal development. Such a switch may be linked to the propensity for periodic breathing (PB) in infancy. To test this idea, we characterized the maturation of the respiratory controller and its effect on breathing stability in ∼10-day-old lambs and 6-mo-old sheep. We measured 1) carotid body sensitivity via dynamic ventilatory responses to step changes in O2 and CO2, 2) steady-state ventilatory sensitivity to CO2 under hypoxic and hyperoxic conditions, 3) the dependence of the apneic threshold on arterial Po2, and 4) the effect of hypoxic or hypercapnic gas inhalation during induced PB. Stability of the system was assessed using surrogate measures of loop gain. Peripheral sensitivity to O2 was higher in newborn than in older animals ( P < 0.05), but peripheral CO2 sensitivity was unchanged. Central CO2 sensitivity was reduced with age, but the slopes of the ventilatory responses to CO2 were the same in hypoxia and hyperoxia. Reduced arterial Po2 caused a leftward shift in the apneic threshold at both ages. Inspiration of hypoxic gas during PB immediately halted PB, whereas hypercapnia stopped PB only after one or two further PB cycles. We conclude that the controller in the sheep remains additive over the first 6 mo of life. Our results also show that the loop gain of the respiratory control system is reduced with age, possibly as a result of a reduction of peripheral O2 sensitivity.

Behavioral arousal in newborn infants and its association with termination of apnea

1991 ◽  
Vol 70 (6) ◽  
pp. 2479-2484 ◽  
Author(s):  
C. K. Thoppil ◽  
M. A. Belan ◽  
C. P. Cowen ◽  
O. P. Mathew
Keyword(s):  
Preterm Infants ◽  
Newborn Infants ◽  
Full Term ◽  
Protective Mechanism ◽  
Behavioral Arousal ◽  
Term Infants ◽  
Obstructive Sleep ◽  
Adults And Children ◽  
Polygraphic Recording ◽  
Arousal Rate

Arousal is an important protective mechanism that aids in the resolution of obstructive sleep apnea in adults and children, but its role in neonatal apnea has not been investigated. The primary aim of the present study was to determine the role of arousal in the termination of apnea in preterm infants. Videorecording was used to identify spontaneous behavioral arousal in a group of healthy full-term (n = 7) and preterm (n = 10) infants before and during polygraphic monitoring of cardiorespiratory variables and in a group of preterm infants with apnea (n = 10) during similar polygraphic monitoring. Spontaneous arousal rates (mean +/- SE) in full-term infants before and during polygraphic monitoring were 0.18 +/- 0.03 and 0.23 +/- 0.07 episodes/min, respectively. Corresponding values in nonapneic preterm infants were 0.24 +/- 0.03 and 0.24 +/- 0.02 episodes/min. In apneic preterm infants, mean spontaneous arousal rate during polygraphic recording was 0.26 +/- 0.02, but it was considerably higher during apneic sleep periods (0.59 +/- 0.17) than during nonapneic sleep periods (0.25 +/- 0.01). The frequency of occurrence of arousal was significantly higher (P less than 0.005) in long vs. short apnea, mixed vs. central apnea, and severe vs. mild apnea. Although a clear association between arousal and apneic resolution was observed in preterm infants, lack of arousal responses in a large number of apneic episodes suggests that behavioral arousal is not essential for the termination of apnea in these infants.

Respiratory system stability and abnormal carbon dioxide homeostasis

1992 ◽  
Vol 72 (3) ◽  
pp. 1186-1193 ◽  
Author(s):  
C. Maayan ◽  
D. W. Carley ◽  
F. B. Axelrod ◽  
J. Grimes ◽  
D. C. Shannon
Keyword(s):  
Control System ◽  
Respiratory System ◽  
Respiratory Control ◽  
Periodic Breathing ◽  
System Stability ◽  
Cycle Duration ◽  
Breathing Patterns ◽  
Venous Pco2 ◽  
Hypoventilation Syndrome ◽  
Mixed Venous

We have tested the hypothesis that interactions among eight parameters of the respiratory and cardiovascular systems that determine the loop gain (LG) of the respiratory CO2 feedback control system might account for the degree of stability or instability of breathing patterns in healthy sleeping volunteers as well as in familial dysautonomia (FD) and congenital central hypoventilation syndrome (CCHS) patients. The predictability of cycle duration was tested as well. We measured the values of CO2 sensitivity, CO2 delivery capacity in the circulation, circulation delay, mean lung volume for CO2, and mixed venous PCO2 in 8 FD patients, 2 CCHS patients, and 19 healthy controls. The values of these parameters were used in a mathematical model to compute the LG of the respiratory control system during sleep for each epoch of respiration analyzed. The strength of the ventilatory oscillations (R) was quantified using power density spectra of the ventilation time series. All subjects were studied at inspiratory O2 concentrations (FIO2) of 0.21 and 0.15; CCHS patients and controls were also studied at 0.12 FIO2 to examine the effect of steady-state hypoxia on respiratory system stability. In 2 FD patients, LG was elevated at both levels of FIO2 and periodic breathing was observed; the values of R were elevated. Elevated mixed venous PCO2 and reduced CO2 delivery capacity were chiefly responsible for the abnormally high LG observed. In three healthy volunteers, high LG and unstable patterns were associated with high chemosensitivity. The CCHS patients, however, remained stable even at 0.12 FIO2 because LG remained equivalent to zero due to a lack of chemosensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)x

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