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At least 19 recordsLinked to original sources
PubMed1979

Effect of feeding on neonatal oxygen consumption.

Oxygen consumption was measured in 9 short-gestation infants before feeding and for an hour after, using a closed-circuit metabolism chamber. Using the same system, O2 consumption of 9 term infants was measured for varying periods, beginning one hour from the end of the last feed. In the short-gestation infants a rise was found in the 15--45 minutes after feeding; O2 consumption then fell, and after 60 minutes had reached prefeed levels. The term infants showed no decrease with time after the first hour, as would be expected if the effect of feeding on O2 consumption extended beyond this. It is concluded that increased O2 demand after appropriate feeding does not extend beyond one hour postprandially.

Eating↗
PubMed1976

Hemorrhagic shock in dogs. Comparison of treatment with shed blood alone versus shed blood plus Ringer's lactate: intravascular pressures, cardiac output, oxygen consumption, arteriovenous oxygen differences, extracellular fluid PO2, electrolyte changes, and survival rates.

The purpose of our study of hemorrhagic shock in dogs was to examine the efficacy of adding Ringer's lactate to shed blood replacement in increasing animal rates. The standard Wiggers' hemorrhagic shock technic was used in two groups of ten animals each. Intravascular pressures, cardiac outut, oxygen consumption, arteriovenous oxygen differences, extracellular fluid PO2 and pH, electrolyte changes, and survival rates were determined. There was a positive correlation between changes in cardiac output, central venous oxygen content, and PO2 and extracellular fluid PO2 as measured using subcutaneously implanted Silastic tubing and perforated plastic balls. Four of the dogs that received shed blood alone survived, whereas five of the dogs that received shed blood plus Ringer's lactate survived. This difference was not statistically significant.

Animals↗
PubMed1979

[Effects of diazepam on oxygen consumption].

Oxygen consumption (VO2) was measured in ten patients before and after the administration of 0.28 mg.kg-1 of diazepam, using a spirometer placed in the circuit of an MA1 respirator functioning on a closed circuit basis. The results showed a significant decrease in VO2 OF 8 p. 100. The differences seen in comparison with previous studies may be explained by differences in the methods of study used. It would appear that this hypometabolic effect is not an intrinsic property of diazepam but rather a consequence of the neurodepressive properties of the drug, on the gamma system in particular.

Adult↗
PubMed1992

Relationship of oxygen consumption and oxygen delivery in surgical patients with ARDS.

Previous studies have described oxygen delivery (DO2) and oxygen consumption (VO2) relationships in patients with ARDS and other acute diseases that suggest occasions when VO2 may be dependent on the supply of oxygen, ie, DO2. We studied 127 postoperative patients who developed ARDS to evaluate the relationship of DO2 to VO2. We found a weak correlation between DO2 and VO2 in the total series (r = 0.49) as well as in several clinical subgroups of patients with ARDS. Moreover, we observed similar relationships in a concurrent group of 218 postoperative patients who did not develop ARDS. We also examined the DO2/VO2 data of individual patients with ARDS to identify instances where flow-dependent VO2 patterns developed into flow-independent VO2 patterns. We were able to identify an apparent plateau in the DO2/VO2 relationships in 29/50 (58 percent) patients where multiple measurements were obtained over a short period of time. Our data are consistent with the concept that the DO2/VO2 relationship in acutely ill early postoperative patients with and without ARDS is affected by antecedent circulatory problems that may lead to tissue hypoxia and tissue oxygen deficiencies that are manifest by flow dependency.

Biological Transport↗
PubMed1992

Fick-derived hemodynamics. Oxygen consumption measured directly vs oxygen consumption calculated from CO2 production under steady state and dynamic conditions.

Indirect calorimetry is being used increasingly as a tool for hemodynamic monitoring via the Fick equation. This investigation was undertaken to examine the use of carbon dioxide elimination (VCO2A) and related respiratory quotient (RQA) to calculate oxygen uptake (VO2A) and estimate oxygen consumption (VO2) during steady-state and dynamic hemodynamic conditions. Nine patients undergoing abdominal aortic surgery were studied intraoperatively and Fick-derived hemodynamic measurements were made using a monitoring system employing indirect calorimetry, pulse oximetry, and pulmonary artery oximetry. Comparisons were made between measured VO2A and calculated VO2A derived from the VCO2A and the initial RQA (RQi), which is assumed not to change. Prior to aortic crossclamping (steady state), there were no significant differences between the measured and calculated methods with respect to oxygen consumption (184 +/- 24 ml/min vs 185 +/- 17 ml/min), oxygen delivery (753 +/- 141 ml/min vs 769 +/- 178 ml/min), and cardiac output (4.7 +/- 0.6 L/min vs 4.7 +/- 0.7 L/min). However, immediately following aortic unclamping (dynamic state), the RQA changed precipitously from the baseline RQi. Consequently, significant differences between the measured and calculated methods were noted in oxygen uptake (213 +/- 41 ml/min vs 193 +/- 25 ml/min, p < 0.001), oxygen delivery (780 +/- 297 ml/min vs 716 +/- 296 ml/min, p < 0.001), and cardiac output (5.8 +/- 2.2 L/min vs 5.3 +/- 1.8 L/min, p < 0.001). Additionally, following unclamping, the peak VO2A was 242 +/- 49 compared with a cVO2A of only 198 +/- 22 (p < 0.01). We conclude that the use of VCO2A to calculate VO2A may lead to erroneous measurements under dynamic conditions, such as unclamping of the abdominal aorta.

Aorta, Abdominal↗
PubMed1979

Physical fitness of the Czechoslovak population between the ages of 12 and 55 years. Oxygen consumption and pulse oxygen.

The authors measured oxygen consumption in a Czechoslovak population aged from 12 to 55 years. An abrupt increase was found between 12 and 18 years, when the maximum was reached (males 3.28, females 2.17 l/min), followed by a slower decrease to 55 years. Relative O2 consumption (per kg body weight) showed a continuous decrease from 12 years, when maximum values were recorded (49 ml/min . kg for boys, 46 ml/min . kg for girls), to 55 (33 ml/min . kg for males, 27 ml/min . kg for females). In the adult population (18--55 years), no differences were observed in the values at the various levels of submaximal loading. The pulse oxygen attained the maximum at 18 (males 16.8, females 11 ml).

Adolescent↗
PubMed1992

The effect of fasting and refeeding on oxygen consumption by rats.

Oxygen consumption is usually measured on fasted animals to avoid the thermal effect of feeding. However, fasting itself may decrease oxygen consumption as a way of conserving energy. The present study was undertaken to determine how long the fasting period should be to avoid the thermal effect of feeding without promoting a further decrease in oxygen consumption by the activation of energy-conservation mechanisms. Oxygen consumption was also measured to evaluate the effect of refeeding after different fasting periods. There was a 16% decrease in oxygen consumption from 0 to 12 h fasting related to the thermal effect of feeding, followed by a less intense (12%) decrease from 12 to 48 h fasting resulting from the energy conservation mechanism. During refeeding, oxygen consumption was higher during the first 30-min period than during the last 30-min period of the 1-h measurement, indicating the probable presence of a cephalic phase of postprandial thermogenesis. We conclude that 12-h fasting is the most appropriate period to avoid the thermal effect of feeding without significantly stimulating the energy conservation mechanism.

Animals↗
PubMed1992

Non-invasive, on-line measurement of oxygen consumption during anesthesia.

Oxygen consumption is usually derived from values measured by a thermodilution catheter, i.e. an invasive procedure, with associated risks and calculation errors. Closed circuit ventilation provides a reliable, non-invasive means of access to this parameter of metabolism. Routine application of closed circuit ventilation requires overcoming many, mainly technical, difficulties (e.g. leakage problems, valve malfunctions, and calculations of gas uptake). We developed a computerized closed circuit anesthesia ventilator without these problems. With this system non-invasively measured oxygen uptake is continuously presented on-line. We discuss three representative patients presenting for surgical repair of an abdominal aneurysm. Besides actual changes in metabolism and depth of anesthesia, success or failure of the operation is visible in the pre- and direct post-clamping period. With resuscitative therapeutic interventions, increase in oxygen consumption gives valuable information under changing conditions. We conclude that closed circuit anesthesia is a safe and valuable method for measurement of oxygen consumption.

Aged↗
PubMed1977

The effect of 2,3-diphosphoglycerate on oxygen consumption burst in thrombin-stimulated platelets.

2,3-Diphosphoglycerate (2,3-DPG) modifies platelet function; it diminishes aggregation and the release reaction. The hypothesis that this occurs through a modification of the intracellular level of cyclic AMP or through an alteration in the synthesis of prostaglandins has been proposed. Since the release reaction occurs simultaneously with a burst in the consumption of oxygen, the authors have studied the effect of 2,3-DPG on oxygen consumption after the addition of thrombin with or without the addition of substances which modify platelet metabolism (aspirin, theophylline, glucagon, etc.). It was observed that 2,3-DPG diminishes oxygen consumption induced by thrombin. This mechanism alters the platelet membrane function.

Adult↗
PubMed1975

Relationship of heat tolerance and oxygen consumption in chickens.

Chicks from lines genetically selected for high or low heat tolerance were compared to lines selected for high or low oxygen consumption. Oxygen consumption, survival time, respiration rate, lung capacity and body weight were determined. Selection for high oxygen consumption ahd high heat tolerance resulted in birds with similar characteristics. The high line birds for both heat tolerance and oxygen consumption had greater oxygen consumption, survival time and lung capacity but lower body weight.

Animals↗