Alveolar data in healthy, awake neonates during spontaneous ventilation: A preliminary investigation

Lagneaux, D; Mossay, C; Geubelle, F; Christiaens, Georges

doi:10.1002/ppul.1950050409

Cited by 29 publications

(10 citation statements)

References 9 publications

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“…We used a VThf of 2 to 3 mL/kg, as the expected dead space has been thought to be about 2.2 mL/kg in healthy awake neonates [23, 24] and the median delivered volume has been documented to be 2.4 mL/kg (range 1.0 to 3.6) [16]. …”

Section: Discussionmentioning

confidence: 99%

High-Frequency Oscillatory Ventilation Combined with Volume Guarantee in a Neonatal Animal Model of Respiratory Distress Syndrome

Luna

Santos

Cortijo

2013

Critical Care Research and Practice

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Objective. To assess volume guarantee (VG) ventilation combined with high-frequency oscillatory ventilation (HFOV) strategy on PaCO2 regulation in an experimental model of neonatal distress syndrome. Methods. Six 2-day-old piglets weighing 2.57 ± 0.26 kg were used for this interventional experimental study. Animals were ventilated during physiologic lung conditions and after depletion of lung surfactant by bronchoalveolar lavage (BAL). The effect of HFOV combined with VG on PaCO2 was evaluated at different high-frequency expired tidal volume (VThf) at constant frequency (f R) and mean airway pressure (mPaw). Fluctuations of the pressure (ΔPhf) around the mPaw and PaCO2 were analyzed before and after lung surfactant depletion. Results. PaCO2 levels were inversely proportional to VThf. In the physiological lung condition, an increase in VThf caused a significant decrease in PaCO2 and an increase in ΔPhf. After BAL, PaCO2 did not change as compared with pre-BAL situation as the VThf remained constant by the ventilator. Conclusions. In this animal model, using HFOV combined with VG, changes in the VThf settings induced significant modifications in PaCO2. After changing the lung condition by depletion of surfactant, PaCO2 remained unchanged, as the VThf setting was maintained constant by modifications in the ΔPhf done by the ventilator.

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Section: Discussionmentioning

confidence: 99%

High-Frequency Oscillatory Ventilation Combined with Volume Guarantee in a Neonatal Animal Model of Respiratory Distress Syndrome

Luna

Santos

Cortijo

2013

Critical Care Research and Practice

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“…The expected anatomical dead space had been thought to be about 2.2 ml/kg 8. A recent study, however, highlighted that the extrathoracic dead space is larger in infants and children because of their relatively large heads.…”

Section: Discussionmentioning

confidence: 99%

Volume delivery during high frequency oscillation

Dimitriou

Greenough

Kavvadia

et al. 1998

Archives of Disease in Childhood - Fetal and Neonatal Edition

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Aim-To examine the delivered volume during "high volume strategy" high frequency oscillation, used as rescue treatment in preterm infants; and to identify factors, other than frequency and oscillatory amplitude, influencing the magnitude of volume delivery. Method-Twenty infants (median gestational age 29 weeks) were studied on 45 occasions. Two oscillator types were used (SensorMedics and SLE). Delivered volume was measured under clinical conditions with the arterial blood gases within a predetermined range. A specially calibrated pneumotachograph system was used. Results-Overall, the median delivered volume was 2.4 ml/kg (range 1.0 to 3.6 ml/kg); on 32 occasions the delivered volume was greater than 2.0 ml/kg and on seven greater than 3.0 ml/kg. The delivered volume related significantly to disease severity; there was an inverse correlation between delivered volume and both the oxygenation index (OI) (r=−0.51) and AaDO 2 (r=−0.54). Conclusion-Delivered volume during HFO may, in certain infants, exceed the anatomical dead space, permitting some direct alveolar ventilation. (Arch Dis Child Fetal Neonatal Ed 1998;78:F148-F150) Keywords: high frequency oscillation; prematurity; delivered volume Gas exchange is maintained during high frequency oscillation (HFO), yet it has been claimed that the delivered volume is small. Although in an animal model delivered volumes of about 2-3 ml/kg have been recorded, 3 in another study 4 the volumes were as low as 10% of the anatomical dead space. This would mean that during HFO mechanisms of gas exchange, other than those occurring during normal tidal breathing, must take place.5 It is, however, diYcult to measure volume delivery accurately at fast frequencies. We have already shown that recording devices with apparently adequate frequencies of response do not behave linearly as the rate is raised above 5 Hz. 6 Fortunately, we have been able to construct a reproducible calibration curve, such that it was possible to use a simple pneumotachograph system to measure reliably the delivered volume during HFO. Results from a pilot study 6 suggested that the delivered volume during HFO could, in certain infants, be as high as 3 ml/kg. The aim of this study was to determine the magnitude of delivered volume during HFO in preterm infants and whether this was influenced by factors other than frequency and oscillatory amplitude. MethodsTwenty infants were studied, their median gestational age was 29 weeks (range 24-37), birthweight 1090 g (range 570-2694), and postnatal age when first studied was 2 days (range 1-16). All the infants had respiratory distress syndrome and had received a median of two doses of exogenous surfactant (range 1-3). Six infants were studied on more than one occasion (median 5, range 2-11). None of the infants was paralysed at the time of study. Estimates were made of the volumes of gas delivered to the lungs during HFO. Infants were receiving HFO as rescue treatment-that is, the clinician in charge felt the blood gases to be poorly responsive to conven...

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“…Four studies were identified that provided VQ data for infants (Lagneaux et al, 1988;Mortola et al, 1992aMortola et al, , 1992bMortola et al, , 1995. Three of these four studies provided data on infants four days or less in age, a time period when breathing patterns are highly irregular.…”

Section: Vq Values For Childrenmentioning

confidence: 99%

Statistical Distributions of Daily Breathing Rates for Narrow Age Groups of Infants and Children

Arcus-Arth¹,

Blaisdell²

2007

Risk Analysis

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Children may be more susceptible to toxicity from some environmental chemicals than adults. This susceptibility may occur during narrow age periods (windows), which can last from days to years depending on the toxicant. Breathing rates specific to narrow age periods are useful to assess inhalation dose during suspected windows of susceptibility. Because existing breathing rates used in risk assessment are typically for broad age ranges or are based on data not representative of the population, we derived daily breathing rates for narrow age ranges of children designed to be more representative of the current U.S. children's population. These rates were derived using the metabolic conversion method of Layton (1993) and energy intake data adjusted to represent the U.S. population from a relatively recent dietary survey (CSFII 1994-1996, 1998). We calculated conversion factors more specific to children than those previously used. Both nonnormalized (L/day) and normalized (L/kg-day) breathing rates were derived and found comparable to rates derived using energy estimates that are accurate for the individuals sampled but not representative of the population. Estimates of breathing rate variability within a population can be used with stochastic techniques to characterize the range of risk in the population from inhalation exposures. For each age and age-gender group, we present the mean, standard error of the mean, percentiles (50th, 90th, and 95th), geometric mean, standard deviation, 95th percentile, and best-fit parametric models of the breathing rate distributions. The standard errors characterize uncertainty in the parameter estimate, while the percentiles describe the combined interindividual and intra-individual variability of the sampled population. These breathing rates can be used for risk assessment of subchronic and chronic inhalation exposures of narrow age groups of children.

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Alveolar data in healthy, awake neonates during spontaneous ventilation: A preliminary investigation

Cited by 29 publications

References 9 publications

High-Frequency Oscillatory Ventilation Combined with Volume Guarantee in a Neonatal Animal Model of Respiratory Distress Syndrome

High-Frequency Oscillatory Ventilation Combined with Volume Guarantee in a Neonatal Animal Model of Respiratory Distress Syndrome

Volume delivery during high frequency oscillation

Statistical Distributions of Daily Breathing Rates for Narrow Age Groups of Infants and Children

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