Hemodynamic physiology and thermoregulation in liposuction

Little is known about the physiology of large-volume liposuction. Patients are exposed to prolonged procedures, general anesthesia, fluid shifts, and infusion of high doses of epinephrine and lidocaine. Consequently, the authors examined the thermoregulatory and cardiovascular responses to liposuction by assessing multiple physiologic factors. The aims of their study were to serially determine hemodynamic parameters perioperatively, to quantify perioperative and postoperative plasma epinephrine levels, and to chronologically document fluctuations in core body temperature. Five female volunteers with American Society of Anesthesiologists' physical status I and II underwent moderate- to large-volume liposuction. Heart rate, blood pressure, mean pulmonary arterial pressure, cardiac index, and central venous pressure were monitored. Serum epinephrine levels and core body temperature were assessed perioperatively. The hemodynamic responses to liposuction were characterized by an increase in cardiac index (57 percent), heart rate (47 percent), and mean pulmonary arterial pressure (44 percent) (p < 0.05). Central venous pressure was not significantly altered. Maximum epinephrine levels were observed 5 to 6 hours after induction. Significant correlations between cardiac index and epinephrine concentrations were shown intraoperatively (r = 0.75). All patients developed intraoperative low body temperatures (mean 35.5 degrees C). An overall enhanced cardiac function was observed in patients subsequent to large-volume liposuction. The etiology of the altered cardiac parameters was multifactorial but may have been attributable in part to the administration of epinephrine, which counters the effects of general anesthesia and operative hypothermia. Additional explanations for raised cardiac output may be hemodilution or emergence from general anesthesia. Elevated mean pulmonary arterial pressure may be a result of subclinical fat embolism demonstrated in previous porcine studies, although fat was not observed in urine. The unchanged central venous pressure levels indicate that young healthy patients with compliant right ventricles can accommodate the fluid loads of large-volume liposuction. Overall hemodynamic parameters remained within safe limits. Within these surgical parameters, patients should be clinically screened for cardiovascular and blood pressure disorders before liposuction is undertaken, and preventative measures should be taken to limit intraoperative hypothermia.     

Augmentation of respiratory sinus arrhythmia in response to progressive hypercapnia in conscious dogs

Respiratory sinus arrhythmia (RSA) may serve to enhance pulmonary gas exchange efficiency by matching pulmonary blood flow with lung volume within each respiratory cycle. We examined the hypothesis that RSA is augmented as an active physiological response to hypercapnia. We measured electrocardiograms and arterial blood pressure during progressive hypercapnia in conscious dogs that were prepared with a permanent tracheostomy and an implanted blood pressure telemetry unit. The intensity of RSA was assessed continuously as the amplitude of respiratory fluctuation of heart rate using complex demodulation. In a total of 39 runs of hypercapnia in 3 dogs, RSA increased by 38 and 43% of the control level when minute ventilation reached 10 and 15 l/min, respectively (P < 0.0001 for both), and heart rate and mean arterial pressure showed no significant change. The increases in RSA were significant even after adjustment for the effects of increased tidal volume, respiratory rate, and respiratory fluctuation of arterial blood pressure (P < 0.001). These observations indicate that increased RSA during hypercapnia is not the consequence of altered autonomic balance or respiratory patterns and support the hypothesis that RSA is augmented as an active physiological response to hypercapnia.     

Acute increase in anastomotic bronchial blood flow after pulmonary arterial obstruction

We examined the acute changes in anastomotic bronchial blood flow (Qbr) serially for the 1st h after pulmonary arterial obstruction and subsequent reperfusion. We isolated and perfused the pulmonary circulation of the otherwise intact left lower lobe (LLL) with autologous blood in the widely opened chest of anesthetized dogs. Qbr was measured from the amount of blood overflowing from the closed pulmonary vascular circuit and the changes in the lobe weight. The right lung and the test lobe (LLL) were ventilated independently. The LLL, which was in zone 2 (mean pulmonary arterial pressure = 14.8 cm H2O, pulmonary venous pressure = 0, alveolar pressure = 5-15 cmH2O), was weighed continuously. The systemic blood pressure, gases, and acid-base status were kept constant. In control dogs without pulmonary arterial obstruction, the Qbr did not change for 2 h. Five minutes after pulmonary arterial obstruction, there was already a marked increase in Qbr, which then continued to increase for 1 h. After reperfusion, Qbr decreased. The increase in Qbr was greater after complete lobar than sublobar pulmonary arterial obstruction. It was unaltered when the downstream pulmonary venous pressure was increased to match the preobstruction pulmonary microvascular pressure. Thus, in zone 2, reduction in downstream pressure was not responsible for the increase in Qbr; neither was the decrease in alveolar PCO2, since ventilating the lobe with 10% CO2 instead of air did not change the Qbr. These findings suggest that there is an acute increase in Qbr after pulmonary arterial obstruction and that is not due to downstream pressure or local PCO2 changes.     

Animal models of pulmonary hypertension: Rho kinase inhibition

Pulmonary Hypertension is a terminology encompassing a range of etiologically different pulmonary vascular diseases. The most common is that termed pulmonary arterial hypertension or PAH; a rare but often fatal disease characterized by a mean pulmonary arterial pressure of >25?mmHg. PAH is associated with a complex etiology highlighted by core characteristics of increased pulmonary vascular resistance and elevation of mean pulmonary artery pressure. When sustained, pulmonary vascular remodeling occurs and eventually patients pass away due to right heart failure. Hypoxic pulmonary vasoconstriction is an early event occurring in pulmonary hypertension due to chronic exposure to hypoxia. While the underlying mechanisms of hypoxic pulmonary vasoconstriction may be controversial, a role for RhoA/Rho kinase mediated regulation of intracellular Ca(2+) has been recently identified. Further study suggests that RhoA may have an integral role in other pathophysiological processes such as cell proliferation and migration occurring in all forms of PH. Indeed Rho proteins are known to play essential roles in actin cytoskeleton organization in all eukaryotic cells and thus Rho and Rho-GTPases are implicated in fundamental cellular processes such as cellular proliferation, migration, adhesion, apoptosis and gene expression. This review focuses on providing an overview of the role of RhoA/Rho kinase in currently available animal models of pulmonary hypertension.     

Normal physiological values for conscious pigs used in biomedical research

Although the domestic pig is rapidly becoming an animal of choice in certain areas of biomedical research requiring a large animal model, effective utilization of the species is often encumbered by a lack of reference values for common functional variables. To address this problem, normal data for over 100 physiologic or related variables were collected from conscious chronically instrumented animals that were maintained under near basal conditions. Included were measurements of body composition, fluid volumes, blood physical and biochemical characteristics, blood gas and acid-base status, plasma hormone levels, energy metabolism, renal function, hemodynamics and pulmonary function. Most porcine values were similar to those collected under comparable conditions from humans. Compared to adult man, however, pigs had higher values for extracellular space, plasma volume, arterial pH, plasma bicarbonate, cardiac output, arterial pressure, expired ventilation, heat production, and core temperature, and lower values for red cell volume, hemoglobin level, plasma osmotic and oncotic pressure, arterial O2 content, renal blood flow and glomerular filtration rate. Many of these deviations were due to immaturity. Nevertheless, we have found pigs to be an excellent large animal model for a variety of functional studies.     

Contributions of hemodynamic monitoring to the treatment of chronic congestive heart failure.

Optimal therapy for congestive cardiac failure requires identification of correctable factors that aggravate it as well as an understanding of its etiology. Increased sympathetic nervous system activity, reduced renal blood flow, and cardiac hypertrophy and dilation are the main compensatory processes that occur in response to cardiac failure. Although they may be of initial benefit in supporting a reduced stroke volume, they may ultimately prove self-defeating. New drugs for the treatment of severe congestive heart failure include dopamine, which has a selective nonadrenergic dilator effect on the renal vascular bed, and dobutamine, which has potent inotropic effects, lowers the left ventricular filling pressure and does not increase the heart rate or the systemic vascular resistance. By reducing both the resistance to left ventricular ejection and the venous return to the right heart, vasodilators result in improved peripheral perfusion and reduced pulmonary congestion. Optimal therapy for refractory cardiac failure can be rationally determined by characterizing the hemodynamic profile through measurement of the mean arterial pressure, the left ventricular filling pressure, the cardiac output and the systemic vascular resistance. The specific therapy can then be effectively and safely delivered by a careful analysis of the dose-response relation as identified by hemodynamic monitoring.     

Noninvasive estimation of pulmonary arterial blood pressure in burned patients with acute respiratory failure.

Pulmonary arterial hypertension develops in acute respiratory failure and mostly an enhanced PADd-PCWP gradient has an important effect on the outcome of that complication. Considering that this critical state of septic burned patients may last for weeks, the long-term direct monitoring of pulmonary arterial blood pressure with indwelling Swan-Ganz catheter is impossible because of the high risk of endocarditis. Therefore, the aim of this study was to elaborate a noninvasive method to estimate the pulmonary arterial hypertension. Determination of cardiac index and pulmonary arterial blood pressure was carried out with Swan-Ganz catheter, P32 Statham transducer, cardiac output computers (Gould IM 1000, Marquette 7010). Extended systolic time interval measurements (with Medicor 661 polygraph completed by PC program package) were performed simultaneously in 7 burned patients (av. age 38.7 ys, means of TBS 38%) with acute respiratory failure at 38 occasions. The values of cardiac indices with the two methods were practically the same CI t = 3.4 +/- 1.21 1/min/m2 CI s = 3.1 +/- 1.10 1/min/m2; regression equation: CI s = 0.874 CIt + 0.135, r = 0.98, n = 38. Close correlations have been found between PAPm and PO2/FiO2 (r = 0.75), as well as between PAP values and some noninvasively measured hemodynamic data. Using these interrelations: 1) regression equations for PAPs., PAPm, PAPd, PCWP, PVRI were elaborated (r values: 0.855, 0.869, 0.681, 0.644, 0.817 respectively); 2) discriminant analysis with noninvasive parameters correctly classified the cases at critical PAPd-PCWP gradient (greater than 4 mm/Hg) in 84%. These results suggest that a continuous noninvasive hemodynamic and blood gas monitoring completed with a periodic bedside computer analysis of the PC-processed data for calculation of the pulmonary arterial pressure may be enough for the therapy during the long-term critical periods.     

Identifying physiological measurements for medical monitoring: implications for autonomous health care in austere environments

In a patient who has lost a significant amount of blood, avoiding cardiovascular collapse and impending circulatory shock depends on the ability to maintain adequate arterial blood pressure in the presence of significant central hypovolemia. Our analysis of hemodynamic, autonomic, and metabolic data obtained from healthy human subjects exposed to progressive reduction in central blood volume and supported by data from trauma patients provide evidence to support the following conclusions: 1. Because of autonomically-mediated compensatory mechanisms, standard vital signs can remain unchanged or change too late, when cardiovascular collapse is imminent. 2. Currently proposed closed-loop resuscitation and oxygen delivery systems controlled by arterial blood pressure and SpO2 may prove inadequate for early intervention decision-support. 3. Continuous capture of PP, ECG R-wave amplitude, indices of HRV, cardiac BRS, and/or muscle PO2 could improve the sensitivity of closed-loop resuscitation and oxygen delivery by providing earlier indications of clinical status.     

Echocardiographic and invasive measurements of pulmonary artery pressure correlate closely at high altitude

Exaggerated hypoxia-induced pulmonary hypertension is a hallmark of high-altitude pulmonary edema (HAPE) and plays a major role in its pathogenesis. Many studies of HAPE have estimated systolic pulmonary arterial pressure (SPAP) with Doppler echocardiography. Whereas at low altitude, Doppler echocardiographic estimation of SPAP correlates closely with its invasive measurement, no such evidence exists for estimations obtained at high altitude, where alterations of blood viscosity may invalidate the simplified Bernoulli equation. We measured SPAP by Doppler echocardiography and invasively in 14 mountaineers prone to HAPE and in 14 mountaineers resistant to this condition at 4,559 m. Mountaineers prone to HAPE had more pronounced pulmonary hypertension (57 +/- 12 and 58 +/- 10 mmHg for noninvasive and invasive determination, respectively; means +/- SD) than subjects resistant to HAPE (37 +/- 8 and 37 +/- 6 mmHg, respectively), and the values measured in the two groups as a whole covered a wide range of pulmonary arterial pressures (30-83 mmHg). Spearman test showed a highly significant correlation (r = 0.89, P < 0.0001) between estimated and invasively measured SPAP values. The mean difference between invasively measured and Doppler-estimated SPAP was 0.5 +/- 8 mmHg. At high altitude, estimation of SPAP by Doppler echocardiography is an accurate and reproducible method that correlates closely with its invasive measurement.     

Thoracic Surgery in the Elderly

With careful attention to details of preoperative, operative and postoperative care, intrathoracic procedures can be carried out safely in the elderly patient. The authors describe such procedures in 111 patients over 60 years of age who presented with a wide variety of primary diseases. Bronchogenic carcinoma, present in 48 patients, was the commonest. One-third of the total group had significant associated disease, usually in the form of coronary artery or chronic respiratory disease. The overall mortality rate was 6.3%.Before surgery, all patients were prophylactically digitalized regardless of their cardiac status. Blood volume estimations were determined in those with excessive weight loss. At operation, measurement of central venous pressure was found to be the best guide to blood replacement.Retention of bronchial secretions was the commonest postoperative complication. This problem can be minimized with intensive chest physiotherapy, adequate hydration, minimal doses of analgesic agents and, when indicated, early tracheostomy.     

房水平单向活瓣式补片对老年先天性心脏病合并重度肺动脉高压 的临床效果分析

目的:探究房水平单向活瓣式补片对老年先天性心脏病伴重度肺动脉高压患者的作用疗效。方法:选取我院心血管科收治的先天性心脏病伴重度肺动脉高压患者80例,随机分为对照组和实验组。对照组40例,予以常规基础药物治疗(波生坦);实验组,在基础药物治疗两个疗程后,采用房水平单向活瓣式补片进行手术治疗。比较两组患者治疗前后的肺动脉压(PAP)、体动脉压(SAP)、肺动脉压/体动脉压(PAP/SAP)、动脉血氧分压(Pa O2)、二氧化碳分压(Pa CO2)及吸氧浓度、右室收缩末期内径变化情况。结果:治疗后,与对照组比较,实验组肺动脉压下降幅度较大(P0.05);与治疗前比较,实验组肺动脉压与体动脉压的比值显著下降,且优于对照组(P0.05);治疗后,实验组动脉血氧分压、二氧化碳分压以及吸氧浓度显著优于对照组(P0.05);治疗后,实验组患者右室收缩末期内径显著小于对照组(P0.05);随访结果:实验组死亡1例、术后活瓣坏死2例、其余37例病情均转好且无复发情况;对照组死亡4例、出现各项并发症16例、剩余20例病情转好。结论:房水平单向活瓣式补片法可有效改善患者的肺动脉压、体动脉压、动脉血氧分压、二氧化碳分压及吸氧浓度、右室收缩末期内径及6 min步行距离,对老年先天性心脏病伴重度肺动脉高压患者疗效显著。     

Peripheral vascular decoupling in porcine endotoxic shock

Cardiac output measurement from arterial pressure waveforms presumes a defined relationship between the arterial pulse pressure (PP), vascular compliance (C), and resistance (R). Cardiac output estimates degrade if these assumptions are incorrect. We hypothesized that sepsis would differentially alter central and peripheral vasomotor tone, decoupling the usual pressure wave propagation from central to peripheral sites. We assessed arterial input impedance (Z), C, and R from central and peripheral arterial pressures, and aortic blood flow in an anesthetized porcine model (n = 19) of fluid resuscitated endotoxic shock induced by endotoxin infusion (7 μg·kg?1·h?1 increased to 14 and 20 μg·kg?1·h?1 every 10 min and stopped when mean arterial pressure <40 mmHg or Sv(O?) < 45%). Aortic, femoral, and radial artery pressures and aortic and radial artery flows were measured. Z was calculated by FFT of flow and pressure data. R and C were derived using a two-element Windkessel model. Arterial PP increased from aortic to femoral and radial sites. During stable endotoxemia with fluid resuscitation, aortic and radial blood flows returned to or exceeded baseline while mean arterial pressure remained similarly decreased at all three sites. However, aortic PP exceeded both femoral and radial arterial PP. Although Z, R, and C derived from aortic and radial pressure and aortic flow were similar during baseline, Z increases and C decreases when derived from aortic pressure whereas Z decreases and C increases when derived from radial pressure, while R decreased similarly with both pressure signals. This central-to-peripheral vascular tone decoupling, as quantified by the difference in calculated Z and C from aortic and radial artery pressure, may explain the decreasing precision of peripheral arterial pressure profile algorithms in assessing cardiac output in septic shock patients and suggests that different algorithms taking this vascular decoupling into account may be necessary to improve their precision in this patient population.     

Pulmonary Embolectomy

Embolectomy was carried out in eight patients with pulmonary emboli. Angiographic diagnosis was obtained in six, and in two cases pulmonary angiography could not be done because of the very critical condition of the patients. In the latter two, diagnosis was made based only on clinical findings. Two patients died in the operating room (25 percent). Six patients were discharged in good condition.It is emphasized that pulmonary embolectomy should be done in cases of pulmonary emboli when a clinical status of shock is present (systolic blood pressure less than 80 mm of mercury and the patient in low cardiac output syndrome) and when there is no response to medical treatment regardless of the degree of obstruction in the pulmonary arterial tree.     

Intravenous acid infusion without lowering arterial pH stimulates breathing

The aim of this study was to determine whether increases in ventilation would occur during intravenous acid infusion even if systemic arterial pH was held constant. In six awake ponies, HCl (500 ml, approximately 0.312 M) was infused into the right atrium at a total dose of 1.0 meq/kg over 18 min while an equivalent dose of NaOH was infused into the left heart to restore systemic arterial pH to normal. Total ventilation increased at the onset of the infusion and remained elevated although systemic arterial pH was normal to slightly alkaline. The increase in ventilation during the initial 2 min of the infusion coincided with an increase in pulmonary arterial PCO2 and decrease in pulmonary arterial pH. As the infusion progressed, however, pulmonary arterial pH and PCO2 returned to near control values due to the recirculation of systemic arterial blood with an acid-base status that had been altered consequent to the hyperventilation. Pulmonary arterial blood pressure was increased significantly during the entire infusion. Infusion of equivalent doses of hypertonic saline led to only minor alterations in the variables that were measured. These experiments demonstrate that this dose of intravenous HCl can increase ventilation independent of reductions in systemic arterial pH. Because increases in ventilation and pulmonary arterial H+ were not well correlated throughout the entire infusion, and pulmonary arterial blood pressure was increased, it is not clear if the mechanism for this ventilatory response is due to stimulation of pulmonary chemoreceptors, pulmonary vascular mechanoreceptors, or some other mechanism unrelated to increases in systemic arterial H+ concentration.     

Hypoxia and angiotensin II infusion redistribute lung blood flow in lambs

To assess the effects of alveolar hypoxia and angiotensin II infusion on distribution of blood flow to the lung we performed perfusion lung scans on anesthetized mechanically ventilated lambs. Scans were obtained by injecting 1-2 mCi of technetium-labeled albumin macroaggregates as the lambs were ventilated with air, with 10-14% O2 in N2, or with air while receiving angiotensin II intravenously. We found that both alveolar hypoxia and infusion of angiotensin II increased pulmonary vascular resistance and redistributed blood flow from the mid and lower lung regions towards the upper posterior region of the lung. We assessed the effects of angiotensin II infusion on filtration pressure in six lambs by measuring the rate of lung lymph flow and the protein concentration of samples of lung lymph. We found that angiotensin II infusion increased pulmonary arterial pressure 50%, lung lymph flow 90%, and decreased the concentration of protein in lymph relative to plasma. These results are identical to those seen when filtration pressure increases during alveolar hypoxia. We conclude that alveolar hypoxia and angiotensin II infusion both increase fluid filtration in the lung by increasing filtration pressure. The increase in filtration pressure may be the result of a redistribution of blood flow in the lung with relative overperfusion of vessels in some areas and transmission of the elevated pulmonary arterial pressure to fluid-exchanging sites in those vessels.     

Pulmonary pressure-flow relationships in the fetal lamb during in utero ventilation

Pressure-flow relationships in the ventilated lung have not been previously determined in undelivered fetal sheep. Therefore we studied 11 late-gestation chronically prepared fetal sheep during positive-pressure ventilation with different gas mixtures to determine the roles of mechanical distension and blood gas tensions on pressure-flow relationships in the lung. Ventilation with 3% O2-7% CO2 produced a substantial fall in pulmonary vascular resistance even though arterial blood gases were not changed. Increases in pulmonary arterial PO2 during ventilation were associated with falls in pulmonary vascular resistance beyond that measured during mechanical distension. Decreases in pulmonary arterial PCO2 and associated increases in pH were also associated with falls in pulmonary vascular resistance. Pulmonary blood flow ceased at a pulmonary arterial pressure that exceeded left atrial pressure, indicating that left atrial pressure does not represent the true downstream component of driving pressure through the pulmonary vascular bed. The slope of the driving pressure-flow relationship in the normal mature fetal lamb was therefore different from the ratio of pulmonary arterial pressure to pulmonary arterial flow. We conclude that mechanical ventilation, increased PO2 and decreased PCO2, and/or increased pH has an important influence on the fall in pulmonary vascular resistance elicited by positive pressure in utero ventilation of the fetal lamb and that the downstream driving pressure for pulmonary blood flow exceeds left atrial pressure.     

Vasoactive mediators and pulmonary hypertension after cigarette smoke exposure in the guinea pig.

The pathogenesis of pulmonary hypertension in patients with chronic obstructive pulmonary disease is not understood. We have previously shown increased levels of mediators that control vasoconstriction (endothelin-1), vascular cell proliferation (endothelin-1 and vascular endothelial growth factor), and vasodilation (endothelial nitric oxide synthase) in the intrapulmonary arteries of animals exposed to cigarette smoke. To determine whether these mediators could be implicated in the structural remodeling of the arterial vasculature and increased pulmonary arterial pressure caused by chronic cigarette smoke exposure, guinea pigs were exposed to daily cigarette smoke for 6 mo. Pulmonary arterial pressures were measured. Intrapulmonary artery structure was analyzed by morphometry, artery mediator protein expression by immunohistochemistry, and artery mediator gene expression by laser capture microdissection and real-time RT-PCR. We found that the smoke-exposed animals developed increases in pulmonary arterial pressure and increased muscularization of the small pulmonary arteries. Gene expression and protein levels of all three mediators were increased, and pulmonary arterial pressure correlated both with the levels of mediator production and with the degree of arterial muscularization. We conclude that chronic smoke exposure produces increased vasoactive mediator expression in the small intrapulmonary arteries and that these mediators are associated with vascular remodeling as well as increased pulmonary arterial pressure. These findings support the idea that hypertension in chronic obstructive pulmonary disease is a result of direct cigarette smoke-mediated effects on the vasculature and suggest that interference with endothelin and VEGF production and activity or augmentation of nitric oxide levels may be beneficial.     

Upstream pressure for systemic to pulmonary flow from bronchial circulation in dogs

Systemic to pulmonary flow from bronchial circulation, important in perfusing potentially ischemic regions distal to pulmonary vascular obstructions, depends on driving pressure between an upstream site in intrathoracic systemic arterial network and pulmonary vascular bed. The reported increase of pulmonary infarctions in heart failure may be due to a reduction of this driving pressure. We measured upstream element for driving pressure for systemic to pulmonary flow from bronchial circulation by raising pulmonary venous pressure (Ppv) until the systemic to pulmonary flow from bronchial circulation ceased. We assumed that this was the same as upstream pressure when there was flow. Systemic to pulmonary flow from bronchial circulation was measured in left lower lobes (LLL) of 21 anesthetized open-chest dogs from volume of blood that overflowed from pump-perfused (90-110 ml/min) pulmonary vascular circuit of LLL and was corrected by any changes of LLL fluid volume (wt). Systemic to pulmonary flow from bronchial circulation upstream pressure was linearly related to systemic arterial pressure (slope = 0.24, R = 0.845). Increasing Ppv caused a progressive reduction of systemic to pulmonary flow from bronchial circulation, which stopped when Ppv was 44 +/- 6 cmH2O and pulmonary arterial pressure was 46 +/- 7 cmH2O. A further increase in Ppv reversed systemic to pulmonary flow from bronchial circulation with blood flowing back into the dog. When net systemic to pulmonary flow from bronchial circulation by the overflow and weight change technique was zero a small bidirectional flow (3.7 +/- 2.9 ml.min-1 X 100 g dry lobe wt-1) was detected by dispersion of tagged red blood cells that had been injected.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reference cardiopulmonary values in normal dogs

The purpose of this project was to collate canine cardiopulmonary measurements from published and unpublished studies in our laboratory in 97 instrumented, unsedated, normovolemic dogs. Body weight; arterial and mixed-venous pH and blood gases; mean arterial, pulmonary arterial, pulmonary artery occlusion, and central venous blood pressures; cardiac output; heart rate; hemoglobin; and core temperature were measured. Body surface area; bicarbonate concentration; base deficit; cardiac index; stroke volume index, systemic and pulmonary vascular resistance indices; left and right cardiac work indices; alveolar partial pressure of oxygen (pO2) ; alveolar-arterial pO2 gradient (A-apO2); arterial, mixed-venous, and pulmonary capillary oxygen content; oxygen delivery; oxygen consumption; oxygen extraction; venous admixture; arterial and mixed-venous blood CO2 contents; and CO2 production were calculated. In the 97 normal, resting dogs, mean arterial and mixed-venous pH were 7.38 and 7.36, respectively; partial pressure of carbon dioxide (pCO2), 40.2 and 44.1 mm Hg, respectively; base-deficit, -2.1 and -1.9 mEq/liter, respectively; pO2, 99.5 and 49.3 mm Hg, respectively; oxygen content, 17.8 and 14.2 ml/dl, respectively; A-a pO2 was 6.3 mm Hg; and venous admixture was 3.6%. The mean arterial blood pressure (ABPm), mean pulmonary arterial blood pressure (PAPm), pulmonary artery occlusion pressure (PAOP) were 103, 14, and 5.5 mm Hg, respectively; heart rate was 87 beats/min; cardiac index (CI) was 4.42 liters/min/m2; systemic and pulmonary vascular resistances were 1931 and 194 dynes.sec.cm-5, respectively; oxygen delivery, consumption and extraction were 790 and 164 ml/min/m2 and 20.5%, respectively. This study represents a collation of cardiopulmonary values obtained from a large number of dogs (97) from a single laboratory using the same measurement techniques.