Comparison of Face Mask, Head Hood, and Canopy for Breath Sampling in Flow-Through Indirect Calorimetry to Measure Oxygen Consumption and Carbon Dioxide Production of Preterm Infants &lt;1500 Grams

Bauer, Karl; Pasel, Katharina; Uhrig, Caroline; Sperling, Peter; Versmold, Hans T.

doi:10.1203/00006450-199701000-00022

Cited by 34 publications

(29 citation statements)

References 15 publications

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“…We have previously shown that the collection of exhaled gas with a sampling device held close to the infant's face but without actually touching it does not result in increased unrest or changes in body temperature (8). During the present measurements, the infants were sleeping 85% of the time.…”

Section: Use In the Clinical Settingmentioning

confidence: 63%

“…all expired air comes out of the ventilated infant's mouth and nose, the methanol burner was placed inside a manikin the size of a preterm infant with the methanol flame burning at the position of the manikin's mouth. The manikin is described in detail elsewhere (8). Gas was sampled by holding the breath collector with the bottom opening above the manikin's face while mechanical ventilation was simulated at a rate of 60/min, PIP of 15 cm H 2 O, PEEP of 3 cm H 2 O (Fig.…”

Section: Protocol For the In Vitro Experimentsmentioning

confidence: 99%

“…The paramagnetic oxygen sensor and the infrared CO 2 sensor in the Deltatrac II have a high resolution of 0.01% (7). We modified the constantflow generator to produce flow rates between 1 and 10 L/min and calibrated the flow generator by quantitative methanol burning (8).…”

Section: Calorimetermentioning

confidence: 99%

“…2). We simulated EE with a miniburner previously built to validate indirect calorimetry in spontaneously breathing infants (8). In short, methanol (methanol extra pure Ͼ99.5%; Merck, Darmstadt, Germany) delivered by a precision infusion pump (Perfusor fm; BraunMelsungen AG, Melsungen, Germany) at a rate of 1 mL/min was burned at the tip of a glass capillary, producing a Vco 2 of 9.2 mL/min and a Vo 2 of 13.8 mL/min (ϭ EE of 0.16 kcal/min or 0.69 kJ/min).…”

Section: Components Of the In Vitro Validation Systemmentioning

confidence: 99%

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In Vitro Validation and Clinical Testing of an Indirect Calorimetry System for Ventilated Preterm Infants That Is Unaffected by Endotracheal Tube Leaks and Can Be Used during Nasal Continuous Positive Airway Pressure

et al. 2001

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Energy expenditure measurements in ventilated preterm infants are difficult because indirect calorimetry underestimates energy expenditure during gas leaks around uncuffed endotracheal tubes routinely used in preterm infants or during nasal continuous positive airway pressure (CPAP). We, therefore, developed a breath collector that simultaneously sampled expired air expelled at the ventilator outlet and escaping via the tube leak from the infant's mouth and nose. Our breath collector was combined with a proprietary calorimeter (Deltatrac II). In vitro validation was done by methanol burning (Vo 2 , 13.8 mL/min; Vco 2 , 9.2 mL/min) during intermittent positive pressure ventilation (IPPV) with two commonly used ventilators (Sechrist IV-100B and Infant Star). Measurement error was determined at different ventilator flows, peak inspiratory pressures of 12-24 cm H 2 O, and during a complete tube leak. The mean measurement error with both ventilators was low (Vo 2 Ϯ 3%, Vco 2 Ϯ 2%) even during a complete tube leak and did not increase with peak inspiratory pressure. The system response time was 2 min. In vivo measurements at the bedside were performed in 25 preterm infants (body weight, 537-1402 g). Energy expenditure during IPPV was 40 Ϯ 9 kcal/kg per day and 46 Ϯ 15 kcal/kg per day during nasal CPAP. The tube leak in the preterm infants studied during IPPV was 0 to 47%, and during nasal CPAP 84 to 97%. In conclusion, indirect calorimetry performed with our breath collector was accurate during IPPV and nasal CPAP and was unaffected by tube leaks. Nutritional intake has to meet energy requirements. Although the EE of spontaneously breathing growing preterm infants is well documented (1, 2), there is a great need for EE measurements in critically ill and ventilated preterm infants (3). These infants can have large variations in EE due to the underlying disease, surgery, therapeutic interventions, or medication. The reason for the paucity of data is the methodologic difficulties for indirect calorimetry in ventilated preterm infants. The routine use of uncuffed endotracheal tubes leads to unpredictable leakage of expired air through mouth and nose (tube leak) in up to 50% of ventilated neonates (4), and the commonly used nasal CPAP represents a maximal tube leak. In previous measurements of EE, many ventilated preterm infants with tube leaks had to be excluded from analysis (5, 6), and no measurements during nasal CPAP have been reported. We, therefore, developed an indirect calorimetry system with the following capabilities: 1) accurate measurements in intubated preterm infants regardless of tube leak, 2) accurate measurements during nasal CPAP, 3) applicable in combination with pressure-controlled constant-flow ventilators, 4) applicable during increased Fio 2 , 5) accurate measurements of low absolute values of Vo 2 and Vco 2 , and 6) easy to use at the bedside without undue disturbance of the patient.The purpose of the present study was to validate this calorimetry system in vitro and to evaluate its performance in ...

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Section: Use In the Clinical Settingmentioning

confidence: 63%

Section: Protocol For the In Vitro Experimentsmentioning

confidence: 99%

Section: Calorimetermentioning

confidence: 99%

Section: Components Of the In Vitro Validation Systemmentioning

confidence: 99%

See 2 more Smart Citations

In Vitro Validation and Clinical Testing of an Indirect Calorimetry System for Ventilated Preterm Infants That Is Unaffected by Endotracheal Tube Leaks and Can Be Used during Nasal Continuous Positive Airway Pressure

et al. 2001

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“…This canopy is commercially available for use on the new-born infant (Datex Division Instrumentarium Corp.). Canopy was used to provide the best patient's compatibility, also some observations suggested a variability of measurements using the canopy, face mask or head hood (Bauer et al, 1997).…”

Section: Methodsmentioning

confidence: 99%

Respiratory quotient changes in full term newborn infants within 30 hours from birth before start of milk feeding

et al. 1998

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Objective: To evaluate substrate utilization in full-term newborn infants, fed every 3±4 h with glucose 10% solution, within 30 h from birth. Design: Random. Setting: Full term newborn infants at the Paediatric Division City Major Hospital, Chair of Paediatrics, Verona University. Subjects: Forty-six newborn infants, 24 females and 22 males of 39 AE 2 weeks gestational age. Methods: Oxygen consumption (VO 2 ) and CO 2 production (VCO 2 ) were measured. Permitting the computation of the respiratory quotient (RQ), which expresses substrate oxidation, at 6 and 30 h from birth. An indirect calorimeter (Deltratrac TMII-MBM-200-DATEX) was used to measure components of energy-balance. Results: Energy expenditure calculated at 6 h was 8.130 (AE1.5757) kJakgah. At 30 h the value changed to 8.858 (AE1.483) kJakgah. Statistical evaluation (t-student) showed a signi®cant (P 0.000) variation in RQ values (6 h: RQ 0.94; 30 h: RQ 0.88). Conclusions: Respiratory quotient suggests an increase of energy derived from fat metabolism at 30 h from birth. Our data con®rm that early breast feeding or formula milk feeding could represent a physiological approach to nutritional regimen of the newborn infant.

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In vitro validation of a metabolic monitor for gas exchange measurements in ventilated neonates

et al. 2000

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Objective: To evaluate the Datex Deltatrac II for measurements in neonates requiring mechanical ventilation. Design: Prospective laboratory evaluation, using a ventilated lung model and gas injection. During simulation of 79 neonatal respiratory settings, assessment of oxygen consumption (V Ç O 2 ), carbon dioxide production (V Ç CO 2 ) and respiratory quotient (RQ) was compared to a reference method (mass spectrometry, wet gas spirometry) using the statistical method of Bland and Altman. Interventions: Respiratory variables, which may influence the accuracy and precision of gas exchange measurements, were varied within the following ranges: inspired oxygen fraction (F I O 2 ): 0.21±0.8, expired carbon dioxide fraction (F E CO 2 ______ ) and inspiratory-expiratory oxygen fraction (DFO 2 ): 0.0032±0.0256, expiratory flow rate: 1.0±2.5 l/min, inspiratory pressure: 10±55 mbar, respiratory rate 25±60/min, constant RQ of 1. This resulted in 79 tests with V Ç CO 2 and V Ç O 2 ranging from 8±64 ml/min. Measurements and results: The coefficient of repeatability for ten single subsequent Deltatrac measurements was 8.09 ml/min for V Ç O 2 and 9.17 ml/min for V Ç CO 2 compared to 2.02 ml/min and 0.90 ml/min for V Ç O 2 and V Ç CO 2 with repeated reference measurements. The coefficient of repeatability of the Deltatrac measurements improved considerably when means of subsequent 5 min intervals were compared: 0.68 ml/min for V Ç O 2 and 0.28 ml/ min for V Ç CO 2 . The difference between the two methods (Deltatracreference) was ±3.8 % (2 s: 11.4 %) for V Ç O 2 , 13.2 % (2 s: 7.9 %) for V Ç CO 2 and 17.6 % (2 s: 16.7 %) for RQ. The agreement between methods deteriorated with smaller (F E CO 2 ______ ) or DFO 2 and increasing F I O 2 . Conclusions: Considering limits of agreement of less than 20 % as clinically acceptable, results for V Ç O 2 assessment indicate acceptable accuracy and precision whereas V Ç CO 2 and RQ assessments exceed this limit. Limited accuracy and precision result from detection of CO 2 following dilution of expiratory gases and increased sensitivity to error propagation by Haldane equations due to the small differences between inspiratory and expiratory gas fractions.

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Comparison of Face Mask, Head Hood, and Canopy for Breath Sampling in Flow-Through Indirect Calorimetry to Measure Oxygen Consumption and Carbon Dioxide Production of Preterm Infants <1500 Grams

Cited by 34 publications

References 15 publications

In Vitro Validation and Clinical Testing of an Indirect Calorimetry System for Ventilated Preterm Infants That Is Unaffected by Endotracheal Tube Leaks and Can Be Used during Nasal Continuous Positive Airway Pressure

In Vitro Validation and Clinical Testing of an Indirect Calorimetry System for Ventilated Preterm Infants That Is Unaffected by Endotracheal Tube Leaks and Can Be Used during Nasal Continuous Positive Airway Pressure

Respiratory quotient changes in full term newborn infants within 30 hours from birth before start of milk feeding

In vitro validation of a metabolic monitor for gas exchange measurements in ventilated neonates

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