The distribution of blood flow, oxygen consumption, and work output among the respiratory muscles during unobstructed hyperventilation.

Robertson, Channing R.; Pagel, Michael A.; Johnson, Robert L.

doi:10.1172/jci108620

Cited by 87 publications

(45 citation statements)

References 29 publications

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“…The values obtained in this study for diaphragmatic blood flow in the quietly breathing neonatal piglet are similar to pre- viously published estimates of ~d i that were based on a variety of techniques applied to a number of different species (28,(33)(34)(35)(36). In contrast to the studies involving adult study subjects, our data point to the conclusion that aminophylline has no vasodilatory effect in the piglet diaphragm.…”

Section: Discussionsupporting

confidence: 87%

The Effect of Aminophylline on Diaphragm Blood Flow in the Piglet

et al. 1989

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ABSTRACT. The effect of aminophylline on diaphrag-more than 8.0 kPa (60 torr) in room air, and a Paco2 equal to matic blood flow was investigated in two groups of newborn or less than 6.7 kPa (50 torr) were accepted for study. The piglets. Six animals were studied during spontaneous animals were anesthetized with sodium pentobarbital (1 5 mg/kg breathing and seven additional animals were paralyzed and intravenously) and studied in the supine position. Subsequent ventilated to assess the effect of aminophylline on blood doses of anesthesia were given as needed to prevent jaw clonus. flow to the nonworking diaphragm. Arterial blood gasesThe trachea was surgically exposed and a metal tracheostomy and pH, cardiac output, and diaphragmatic blood flow were tube was inserted. A femoral artery and vein were cannulated to measured before and 20 min after infusion of 20 mg/kg monitor blood pressure, assess arterial blood gases and pH, and aminophylline. Blood theophylline concentrations averaged administer drugs. Arterial pH and blood gas tensions were meas-117 wmol/L (21 pg/mL) in both groups of animals. Heart ured with a Corning 168 blood gas analyzer (Corning Glass rate increased significantly in all animals. Cardiac output Works, Medfield, MA). Rectal temperature was continuously increased significantly only in spontaneously breathing an-monitored (Telethermometer 43TA, Yellow Springs Instrument, imals. Aminophylline had no effect on blood flow to the Yellow Springs, OH) and maintained between 38.5 and 39.5" C. costal or crural portions of the diaphragm in either the (23) with a radiant warmer. A 5 French thermodilution catheter paralyzed or spontaneously breathing animals. (Pediatr was placed into the left branch of the pulmonary artery via the Res 26:196-199, 1989) right external jugular vein under fluoroscopy. Cardiac output determinations were made in triplicate using a 9520A Cardiac Abbreviation Output computer (American Edwards Laboratories, Irvine, CA). Radiolabeled microspheres were used to measure diaphragmatic ~d i , diaphragmatic blood flow blood flow utilizing the reference sample method described by Heymann et al. (24). A polyethylene catheter (PE 90) was advanced into the left ventricle via the left carotid artery under fluoroscopic guidance for microsphere injection. Location of Methylxanthines, and in particular the theophylline prepara-catheter was confirmed by pressure tracing and at postmortions, have been proposed as adjunctive therapy in weaning tem. A second polyethylene catheter was placed into a fanoral premature infants from mechanical ventilation (1, 2). In addition artery for withdrawal of the reference sample using a calibrated to their bronchodilatory effect (3-5) and central respiratory pump (Harvard Millis, MA). The 15-P (6-9), methylxanthines improve diaphragmatic force microspheres labeled with either 4 6 S~, 95m, 'O3Ru, Or I4'Ce output (1 0-1 3) and ameliorate the effects of diaphragmatic fa-(DuPonf Wilmington, DE) were used in these experiments. tigue 14-16) in adult humans and exp...

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Section: Discussionsupporting

confidence: 87%

The Effect of Aminophylline on Diaphragm Blood Flow in the Piglet

et al. 1989

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“…Thus, the relative efficiency of the respiratory muscles in producing external mechanical work on the lungs should be inversely re-lated to the total blood flow to the respiratory muscles. This inverse relationship allows a comparison of the efficiency under the various conditions of expiratory threshold loads produced in this study vs. inspiratory resistive loads (5) and unobstructed hyperventilation produced by CO2 rebreathing in our earlier studies (4). Because of the complex mechanics of the combined thorax and abdomen, it would not be surprising if the relative efficiency of muscular contraction was different under these different load conditions.…”

Section: Introductionmentioning

confidence: 80%

“…The distribution of augmented blood flow among respiratory muscles as the work of breathing is increased should provide an accurate quantitative index of the distribution of muscular effort, since blood flow to skeletal muscle is proportional to effort expended by the muscle (1)(2)(3). In previous studies we have described the increases in blood flow observed in each muscle of respiration during mechanical ventilation and during quiet spontaneous breathing (4), during,breathing against graded inspiratory resistances (5), and during unobstructed hyperventilation induced by the CO2 retention during rebreathing (4).…”

Section: Introductionmentioning

confidence: 99%

Respiratory Muscle Blood Flow Distribution during Expiratory Resistance

Robertson¹,

Eschenbacher²,

Johnson³

1977

J. Clin. Invest.

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A B S T R A C T When work load on the respiratory system is increased the relative increase in blood flow to each of the muscles of breathing provides an index of how the augmented effort of breathing is partitioned among the different muscles. We have used a radioactive microsphere technique to measure blood flow to each ofthe muscles ofrespiration in supine dogs during unobstructed respiration and breathing against graded expiratory threshold loads. 79% of the augmented flow went to expiratory muscles; of this increased flow to expiratory muscles 74% went to abdominal wall muscles and 26% to internal intercostals. In our earlier studies of hyperventilation induced by CO2 rebreathing where expiratory work loads were low, 44% of the increase in flow went to expiratory muscles; of this, only 39% went to abdominal wall muscles and 61% to intemal intercostals. During inspiratory resistance which produced small increases in expiratory work, 27% of the increase in blood flow went to expiratory muscles; of this, only 37% went to abdominal wall muscles and 63% to intemal intercostals. These results suggest that the internal intercostals are predominantly used for expiration when expiratory work loads are low, whereas the abdominal wall muscles are predominantly used when loads are high.For similar rates of pressure-volume work done on the lung, the total respiratory muscle blood flow is significantly greater during expiratory loads than during unobstructed hyperventilation or inspiratory loads. Thus, the abdominal wall muscles that are utilized for overcoming high pressure expiratory loads are relatively inefficient in converting metabolic energy into pressure-volume work.

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“…80 It has been previously demonstrated that as WOB increases, there is significant increase in blood flow to the respiratory muscles and an attendant increase in oxygen consumption. 81 CPAP's role in reducing this WOB explains why overall oxygen consumption falls in HF patients on CPAP. 82 Finally, because diaphragmatic muscle fatigue is related to muscle tension produced and amount of time in spent in inspiration, 83,84 CPAP by reducing both intrathoracic pressure swings and respiratory rate prevents respiratory muscle fatigue and the development of hypercapnic respiratory failure.…”

Section: Effect Of Positive Airway Pressure On Lung Function In Acutementioning

confidence: 99%

Heart Failure and the Lung

Kee

Naughton

2010

Circ J

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Heart failure (HF) is a highly prevalent disease that leads to significant morbidity and mortality. There is increasing evidence that the symptoms of HF are exacerbated by its deleterious effects on lung function. HF appears to cause airway obstruction acutely and leads to impaired gas diffusing capacity and pulmonary hypertension in the longer term. It is postulated that this is the result of recurrent episodes of elevated pulmonary capillary pressure leading to pulmonary oedema and pulmonary capillary stress fracture, which produces lung fibrosis. It is likely that impaired lung function impairs the functional status of HF patients and makes them more prone to central sleep apnoea. (Circ J 2010; 74: 2507 - 2516

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The distribution of blood flow, oxygen consumption, and work output among the respiratory muscles during unobstructed hyperventilation.

Cited by 87 publications

References 29 publications

The Effect of Aminophylline on Diaphragm Blood Flow in the Piglet

The Effect of Aminophylline on Diaphragm Blood Flow in the Piglet

Respiratory Muscle Blood Flow Distribution during Expiratory Resistance

Heart Failure and the Lung

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