Influence of Bag Volume on Reproducibility of Inert Gas Rebreathing Pulmonary Blood Flow Measurements in Patients with Pulmonary Diseases

Saur, Joachim; Kraus, F; Brade, Joachim; Haghi, Dariusch; Behnes, Michael; Hoffmann, Ursula; Borggrefe, Martin; Kaden, Jens J.

doi:10.1007/s00408-013-9494-0

Cited by 2 publications

(3 citation statements)

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“…This may be due to the increased breathing frequency required, which increases oxygen demand from respiratory muscles and in turn increases cardiac output [18]. Other studies have reported an underestimation of cardiac output by the N 2 O rebreathing technique compared to other techniques at rest and during exercise [36,37], with > 30 % of recorded values lower than what was considered possible [39]. This is possibly due to recirculation of N 2 O [20], which could reduce the alveolar-arterial diffusion gradient for N 2 O and attenuate further N2O uptake [23].…”

Section: Discussionmentioning

confidence: 99%

“…Cardiac magnetic resonance imaging is currently accepted as the non-invasive gold standard method for cardiac output assessment [14,15]. However, this technique is expensive, time consuming and not applicable in daily practice [36].…”

Section: Introductionmentioning

confidence: 99%

“…In principle, it functions by measuring the rate of clearance of a physiologically inert gas from the pulmonary capillary circulation, which is directly proportional to pulmonary blood flow [9]. If the inert gas completely diffuses into the pulmonary capillary circulation (i. e., in the absence of significant pulmonary shunt flow) pulmonary blood flow equals total cardiac output [36]. Previous studies have reported promising results for monitoring cardiac output using this method when compared with the invasive gold standard thermodilution [19,20], and more recently, cardiac magnetic resonance imaging the noninvasive gold standard [15,21].…”

Section: Introductionmentioning

confidence: 99%

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Reproducibility of Inert Gas Rebreathing Method to Estimate Cardiac Output at Rest and During Cardiopulmonary Exercise Stress Testing

et al. 2019

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ABStR AC tThe present study evaluated reproducibility of the inert gas rebreathing method to estimate cardiac output at rest and during cardiopulmonary exercise testing. Thirteen healthy subjects (10 males, 3 females, ages 23-32 years) performed maximal graded cardiopulmonary exercise stress test using a cycle ergometer on 2 occasions (Test 1 and Test 2). Participants cycled at 30-watts/ 3-min increments until peak exercise. Hemodynamic variables were assessed at rest and during different exercise intensities (i. e., 60, 120, 150, 180 watts) using an inert gas rebreathing technique. Cardiac output and stroke volume were not significantly different between the 2 tests at rest 7.4 (1.6) vs. 7.1 (1.2) liters min − 1 , p = 0.54; 114 (28) vs. 108 (15) ml beat − 1 , p = 0.63) and all stages of exercise. There was a significant positive relationship between Test 1 and Test 2 cardiac outputs when data obtained at rest and during exercise were combined (r = 0.95, p < 0.01 with coefficient of variation of 6.0 %), at rest (r = 0.90, p < 0.01 with coefficient of variation of 5.1 %), and during exercise (r = 0.89, p < 0.01 with coefficient of variation 3.3 %). The mean difference and upper and lower limits of agreement between repeated measures of cardiac output at rest and peak exercise were 0.4 ( − 1.1 to 1.8) liter min − 1 and 0.5 ( − 2.3 to 3.3) liter min − 1 , respectively. The inert gas rebreathing method demonstrates an acceptable level of test-retest reproducibility for estimating cardiac output at rest and during cardiopulmonary exercise testing at higher metabolic demands.

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