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Rosenfeldt FL, Ou R, Smith JA, Mulcahy DE, Bannigan JT, Haskard MR. Evaluation of a miniature antimony electrode for measurement of myocardial pH. J Med Eng Technol 1999; 23:119-26. [PMID: 10561822 DOI: 10.1080/030919099294168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Myocardial pH reflects the metabolic status of the heart and pH monitoring is an invaluable way to monitor the efficacy of myocardial protection during cardiac surgery. We developed a miniature antimony electrode for pH measurement in the heart. We examined the sensitivity, accuracy and the effects of temperature and oxygen tension on pH readings with this electrode in standard buffers and in anaesthetized dogs. In buffers the antimony electrode exhibited a gradient of -50.3 +/- 1.8 mV pH-1 at 25 degrees C, close to the Nernstian slope and showed a high correlation with conventional glass electrode readings (mean difference 0.027 +/- 0.0035 pH, r2 = 0.97). With increasing temperature the antimony electrode pH readings increased by 0.03 +/- 0.002 pH degree C(-1). With increasing PO2 the pH reading decreased (-0.73 pH/log PO2 mm Hg, r2 = 0.96). In the dog heart the antimony electrode showed a decrease in myocardial pH with increasing PCO2, and an increase in pH when NaHCO3 was given intravenously. Coronary occlusion resulted in paradoxically higher pH readings with the antimony electrode due to the effect of lowered myocardial PO2 interfering with pH measurement. The dissolution of antimony from the electrode in blood plasma was tested and found to be low. These studies suggest that antimony electrodes have low toxicity and provide accurate pH determinations under conditions of constant PO2. For more widespread clinical application, the problem of oxygen interference needs to be solved.
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Affiliation(s)
- F L Rosenfeldt
- Baker Medical Research Institute, Heart and Lung Transplant Service, Prahran, Victoria, Australia
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2
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Affiliation(s)
- R G Favaloro
- Institute of Cardiology and Cardiovascular Surgery of the Favaloro Foundation, Buenos Aires, Argentina
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Ferrari R, Alfieri O, Curello S, Ceconi C, Cargnoni A, Marzollo P, Pardini A, Caradonna E, Visioli O. Occurrence of oxidative stress during reperfusion of the human heart. Circulation 1990; 81:201-11. [PMID: 2297827 DOI: 10.1161/01.cir.81.1.201] [Citation(s) in RCA: 201] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We have investigated the relation between occurrence of myocardial oxidative stress and functional recovery during postischemic reperfusion in 20 selected patients subjected to aortocoronary bypass grafting. Patients were selected for having normal percent ejection fraction and left ventricular end-diastolic pressure before the operation. Occurrence of oxidative stress was assessed by measuring the formation and release of oxidized glutathione (GSSG) in the coronary sinus immediately before aortic cross-clamp, 1, 5, 10, and 20 minutes after removal of aortic cross-clamp, and 10 and 20 minutes after the end of cardiopulmonary bypass. Reduced glutathione (GSH), lactate, and creatine phosphokinase release were also monitored with the same timing. Standard hemodynamic measurements were recorded by means of a triple-lumen thermodilution pulmonary artery catheter before sternotomy, 15 minutes after the end of cardiopulmonary bypass, and during the 24 hours after termination of cardiopulmonary bypass. Reperfusion in patients after a short period of ischemia (less than 30 minutes; group 1) resulted in a small and transient release in the coronary sinus of GSSG and GSH and in a progressive improvement of hemodynamic parameters reaching a stable state 4 hours after the operation. In patients with a period of ischemia longer than 30 minutes (group 2), reperfusion induced a marked and sustained release of lactate, GSH, and GSSG; the arteriocoronary sinus difference for GSSG was still negative after the end of cardiopulmonary bypass. The arteriocoronary sinus difference for creatine phosphokinase also remained negative for as long as 20 minutes after cardiopulmonary bypass, and the rate of functional recovery was significantly delayed, reaching the values of group 1 only 12 hours after the operation. In these patients there was a positive correlation (r = 0.88, p less than 0.01) between the duration of ischemia and the myocardial arteriovenous difference for GSSG. In addition, there was a negative correlation between the arteriocoronary sinus difference for GSSG and cardiac index measured 2, 4, and 6 hours after the operation. These data suggest for the first time that, depending on the severity of the ischemic period, oxidative stress occurs during reperfusion of patients with coronary artery disease who are subjected to heart surgery and that it may be linked with a delay in postoperative recovery of cardiac function.
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Affiliation(s)
- R Ferrari
- Cattedra di Cardiologia, University of Brescia, Italy
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4
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Kobayashi H, Pelster B, Piiper J, Scheid P. Significance of the Bohr effect for tissue oxygenation in a model with counter-current blood flow. RESPIRATION PHYSIOLOGY 1989; 76:277-88. [PMID: 2501842 DOI: 10.1016/0034-5687(89)90069-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Counter-current arrangement of afferent and efferent blood flow in tissues is commonly considered to be detrimental to tissue oxygenation, since O2 diffusion would shunt O2 away from the tissue. We have investigated the combined effects of counter-current CO2 and O2 exchange in a simple model, paying particular attention to the Bohr effect. We have obtained the following main results. (1) Back-diffusion of CO2 leads to increasing CO2 partial pressure (PCO2) and CO2 content along the afferent vessel. This is enhanced when fixed acid is released by the tissue into the venous blood, e.g. during hypoxia, which leads to a further PCO2 increase therein. (2) The increasing PCO2, with concomitant decrease in pH, in the afferent blood leads to a decrease in blood O2 affinity (Bohr effect) and thus results in increased PO2. (3) The resulting O2 diffusion shunt diminishes the O2 content in afferent blood, but for most conditions its PO2 remains higher than without the Bohr effect. (4) During hypoxia, both the PO2 in blood reaching the tissue (Pta) as well as in that leaving it (Ptv) are significantly elevated above the level without the Bohr effect. Moreover, with fixed acid release both Pta and Ptv for O2 can be higher than the arterial PO2 value. (5) During hyperoxia, O2 diffusion shunt prevents the tissue PO2 levels from increasing to levels that might be regarded as toxic. It is concluded that a diffusion shunt in tissues stabilizes the O2 partial pressure at the tissue when it varies in arterial blood (hypoxia or hyperoxia).
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Affiliation(s)
- H Kobayashi
- Institut für Physiologie, Ruhr-Universität, Bochum, F.R.G
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5
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Kawasuji M, Kawajiri F, Matsunaga Y, Watanabe G, Iwa T. Intraoperative evaluation of coronary bypass grafts by measuring myocardial blood flow using the electrolytic hydrogen clearance method. THE JAPANESE JOURNAL OF SURGERY 1988; 18:509-13. [PMID: 3265968 DOI: 10.1007/bf02471483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The regional myocardial blood flow (MBF) was measured in 33 patients who underwent coronary bypass graft surgery in order to evaluate the efficiency of coronary bypass grafts in restoring MBF. MBF was measured by the electrolytic hydrogen clearance method during the coronary bypass surgery. The mean prebypass MBF was 161 +/- 19, 162 +/- 12, 80 +/- 12, 43 +/- 14, 104 +/- 18 ml/min/100 g in segments supplied by the left anterior descending coronary artery (LAD) showing less than or equal to 50 per cent, 75 per cent, 90 per cent, 99 per cent, and 100 per cent stenosis with collaterals, respectively. After bypass grafting of the LAD, the mean MBF increased from 70 +/- 13 and 126 +/- 12 ml/min/100 g to 133 +/- 14 and 163 +/- 9 ml/min/100 g in the segments with and without infarction, respectively. The mean postbypass MBF was 149 +/- 10 and 152 +/- 14 ml/min/100 g in the segments supplied by the LAD bypassed with saphenous vein grafts and mammary artery grafts, respectively. Postbypass MBF was dependent upon the magnitude of myocardial infarction. Measurement of MBF by the electrolytic hydrogen clearance method made it possible to quantitatively evaluate myocardial perfusion at the time of operation. It also provided direct information about the effectiveness of myocardial revascularization.
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Affiliation(s)
- M Kawasuji
- Department of Surgery 1, Kanazawa University School of Medicine, Japan
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6
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Johnson DL, Lahorra JA, Gott VL, Gardner TJ. Reducing intraoperative myocardial acidosis by continuous cardioplegic perfusion via the coronary sinus. J Surg Res 1988; 44:625-30. [PMID: 3379940 DOI: 10.1016/0022-4804(88)90093-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Continuous retrograde coronary sinus perfusion (RCSP) can deliver cardioplegic solution homogeneously to the myocardium via the disease-free venous system. However, administration of cardioplegic solution through the coronary venous system necessitates low pressure infusion which may limit the rate of cardioplegic delivery. In addition, infusion of the solution at low flow rates may not prevent the development of myocardial acidosis during arrest. To determine if RCSP is capable of limiting intraoperative myocardial acidosis, open-chest pigs, monitored by intramyocardial pH probes, underwent cardioplegic arrest with a single dose aortic root infusion followed by a 45-min period of no RCSP (Group 1), RCSP of 25 mEq/liter bicarbonate-buffered cardioplegic solution (Group 2), RCSP of blood-buffered cardioplegic solution (Group 3), and RCSP of histidine-buffered cardioplegic solution (Group 4). There were no significant differences between the groups with respect to baseline pH, with a range of 7.27 to 7.32. At the end of the 45-min arrest period, Group 2 had a statistically higher pH, 7.06 +/- 0.08, compared to Group 1, 6.74 +/- 0.08 (P less than 0.05). Hearts in Groups 3 and 4 demonstrated preservation of preischemic pH levels after 45 min of arrest, 7.29 +/- 0.07 and 7.37 +/- 0.10, respectively, significantly higher than either Group 1 or 2 (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- D L Johnson
- Division of Cardiac Surgery, Johns Hopkins Medical Institutions, Baltimore, Maryland 21205
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Abstract
Most cardiac surgical procedures require the use of prolonged induced myocardial ischemia. Experimental models of global myocardial ischemia which mimic cardiac surgical techniques have been developed to investigate the possibility of oxygen free radical development during prolonged myocardial ischemia or upon reperfusion. In such experiments, various free radical scavenging agents, including superoxide dismutase, catalase, and mannitol, have been shown to improve the tolerance of the heart to protracted global ischemia. Use of these agents has improved cardiac functional recovery and has attenuated the biochemical and structural changes which occur due to prolonged ischemia and reflow. In a recently developed porcine experimental model, the effects of preexisting regional myocardial ischemia with superimposed global ischemia and reperfusion have been studied, with free radical scavenging agents administered in an attempt to reduce myocardial infarction and improve regional functional recovery. In most such studies completed to date, free radical scavenging agents have resulted in better myocardial preservation, suggesting, at least indirectly, that there may be an oxygen free radical-mediated component of the ischemia-reperfusion injury seen in such models. Techniques for directly measuring myocardial oxygen free radical levels may allow for early clarification of the development of such toxic species in the clinical cardiac surgical setting.
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Affiliation(s)
- T J Gardner
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205
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Siouffi SY, Kwasnik EM, Khuri SF. Methods for the metabolic quantification of regional myocardial ischemia. J Surg Res 1987; 43:360-78. [PMID: 3309463 DOI: 10.1016/0022-4804(87)90093-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
An adequate balance between oxygen supply and demand is a basic requirement for normal cardiac function. When oxygen supply does not meet the demand, progressive cellular damage occurs leading to cardiac dysfunction and, ultimately, tissue death. While traditionally "ischemia" has been defined as decreased oxygen supply secondary to a decrease in blood flow, and "hypoxia" as decreased oxygen supply secondary to a decrease in oxygen tension, this review defines ischemia in its broader sense, namely as a pathophysiologic state in which there is a lack of oxygen relative to the demand for it. In a large number of experimental studies involving the heart, there is need to promptly recognize the ischemic state, to monitor its course in vivo, and to quantify it. Because of cardiac autoregulatory mechanisms, research methods which attempt to quantify supply (e.g., measurement of myocardial blood flow) and/or demand (e.g., measurement of myocardial oxygen consumption) do not necessarily reflect the status of the balance between supply and demand. An imbalance between myocardial supply and demand is more likely to be reflected by metabolic fluxes and by the accumulation of products specific to the ischemic state. Thus, the purpose of this review is to summarize the various methods available to the cardiac surgical investigator today for the metabolic quantification of myocardial ischemia. Due to the complexity of the heart and its inherent regional differences, myocardial ischemic changes are frequently regional in nature. Thus, this review will address metabolic methods for the regional quantification of myocardial ischemia.
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Affiliation(s)
- S Y Siouffi
- Department of Surgery, West Roxbury Veterans Administration Medical Center, Massachusetts 02132
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Levy BI, Pinard E, Michel JB, Tedgui A, Seylaz J. Transmural gradient of tissue gas tensions in the canine left ventricular myocardium during coronary clamping and reactive hyperemia. Pflugers Arch 1986; 407:388-95. [PMID: 3095786 DOI: 10.1007/bf00652623] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Mass spectrometry was used for the continuous, simultaneous and quantitative measurement of oxygen (PO2) and carbon dioxide (PCO2) partial pressures in the subendocardial and subepicardial layers of the left ventricle in 11 anaesthetized ventilated dogs. Under control conditions, PO2 was significantly lower in the subendocardium (13.5 +/- 4.5 mm Hg) than in the subepicardium (20.7 +/- 2.3 mm Hg), whereas PCO2 did not differ significantly (43 +/- 8.8 and 51 +/- 9.2 mm Hg respectively). These variables were not correlated with blood pressure or coronary blood flow. Subendocardial and subepicardial PO2 decreased less than 5 s after coronary occlusion. These changes were more rapid and severe in the subendocardium. After occlusion for 90 s: subendocardial PO2 was 4.1 +/- 6.3 mm Hg while subepicardial PO2 was 6.7 +/- 15.0 mm Hg (P less than 0.05). PCO2 reached peak values of 56 +/- 25 mm Hg subendocardial and 82 +/- 22 mm Hg subepicardial at 2.67 +/- 0.71 min and 3.43 +/- 0.93 min after coronary clamping. A reactive hyperemia occurred after coronary unclamping with different time courses and amplitudes for systolic and diastolic stroke flows while PO2 recovered with different kinetics. Subendocardial PO2 increased with a lower initial slope, probably in relation with the delay in the diastolic hyperemia. The observed delayed subendocardial hyperoxia, unrelated to the hyperemia, may indicate a delay in the recovery of normal work and metabolism in the inner layers of the myocardium.
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Abstract
A new system for the on-line monitoring of intramyocardial pH and temperature has been used in more than 120 patients undergoing cardiac surgery. This article summarizes the experimental studies on which the system was based and highlights some of the data obtained and explains their significance.
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11
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Schuchhardt S. Myocardial oxygen pressure: mirror of oxygen supply. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1985; 191:21-35. [PMID: 3914204 DOI: 10.1007/978-1-4684-3291-6_2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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12
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Time course of ischemic alterations during normothermic and hypothermic arrest and its reflection by on-line monitoring of tissue pH. J Thorac Cardiovasc Surg 1983. [DOI: 10.1016/s0022-5223(19)39156-1] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Shields CB, Roberts E, Numoto M. Brain tissue pO2 and pCO2 levels before and after cerebral revascularization. JOURNAL OF MICROSURGERY 1980; 1:267-71. [PMID: 6776224 DOI: 10.1002/micr.1920010404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Microvascular surgical techniques have made possible the improvement of cerebral blood flow, as demonstrated by angiography and by regional cerebral blood flow research. In this study, simultaneous mass spectrometer determinations of brain tissue and blood pO2 and pCO2 levels were used to evaluate the effectiveness of common carotid-supraclinoid carotid anastomoses (CC-SCA) in dogs. With blood pCO2 maintained at a constant level, the baseline brain tissue pO2 and pCO2 levels were recorded. During the CC-SCA procedure, which involved brain retraction and temporary vascular occlusion, brain tissue pO2 levels fell to 40% of baseline and pCO2 levels rose by 35%. Following restoration of flow via the anastomosis, the brain tissue pO2 and pCO2 levels again reached baseline.
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Kikuchi Y, Horimoto M, Koyama T. Reduced deformability of erythrocytes exposed to hypercapnia. EXPERIENTIA 1979; 35:343-4. [PMID: 446609 DOI: 10.1007/bf01964342] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The effect of hypercapnia on the deformability of erythrocytes was studied by means of a nuclepore membrane filter method. A decrement of the deformability by 20--40% was observed when PCO2 was increased from 50 mm Hg to 200 mm Hg, accompanied with an increment of 5% in hematocrit value.
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15
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Jalonen J, Havia T, Halkola L, Niinikoski J. Elevated mid-myocardial oxygen tension in the fibrillating heart during cardiopulmonary bypass. SCANDINAVIAN JOURNAL OF THORACIC AND CARDIOVASCULAR SURGERY 1979; 13:227-32. [PMID: 542825 DOI: 10.3109/14017437909100556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mid-myocardial tissue oxygen tension was measured in the left ventricular wall of the hearts of ten dogs by means of a Silastic tonometer implanted earlier. During cardiopulmonary bypass, myocardial PO2 was significantly higher in a spontaneously fibrillating heart (5.4 +/- 0.9 kPa) than during the initial beating period (3.7 +/- 0.5 kPa) or after defibrillation (4.0 +/- 0.7 kPa). In general, there was a tendency towards increased myocardial blood flow, elevated oxygen uptake and reduced coronary sinus oxygen content during ventricular fibrillation, compared with the situation in the beating heart. Myocardial lactate extraction remained unchanged during the different phases of cardiopulmonary bypass. The increase in mid-myocardial oxygen tension during ventricular fibrillation was probably due to increased total myocardial blood flow and redistribution of regional myocardial circulation. In two additional dogs, ventricular fibrillation resulted in left ventricular distension and a simultaneous fall of myocardial oxygen tension, which indicates the necessity of left ventricular decompression suction in a fibrillating heart during cardiopulmonary bypass.
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Favaloro RG. Direct myocardial revascularization: a 10 year journey. Myths and realities. Louis F. Bishop Lecture. Am J Cardiol 1979; 43:109-29. [PMID: 364972 DOI: 10.1016/0002-9149(79)90053-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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18
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Schaff HV, Dombroff R, Flaherty JT, Bulkley BH, Hutchins GM, Goldman RA, Gott VL. Effect of potassium cardioplegia on myocardial ischemia and post arrest ventricular function. Circulation 1978; 58:240-9. [PMID: 307460 DOI: 10.1161/01.cir.58.2.240] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To assess the effects of moderate potassium cardioplegia (37 mEq/l KCl) on the severity of myocardial ischemia during arrest and on post arrest ventricular function, 32 isolated, isovolumic feline hearts were studied before, during and 1 hour after ischemic arrest. Normothermia (37 degrees C) was maintained in the remaining 16 hearts, eight without KCl and eight with KCl. Hypothermia (27 degrees C) was maintained in the remaining 16 hearts, eight with KCl and eight without KCl. Myocardial oxygen (PmO2) and carbon dioxide tensions (PmCO2) were measured by mass spectrometry. Maximum developed intraventricular pressure (max DP) and max dP/dt were used as indices of performance. Compared with normothermic or hypothermic arrest alone, the addition of potassium cardioplegia resulted in a significant reduction in the peak PmCO2 measured during the arrest period. Hypothermia alone resulted in morphologic evidence of improved myocardial preservation and a significant reduction in peak PmCO2 compared with normothermia. Post arrest ventricular function was best with the combination of hypothermic arrest and potassium cardioplegia (max DP = 96 +/- 6% of control and max dP/dt = 99 +/- 5% of control). These data suggest that the beneficial effects of postassium cardioplegia and 27 degrees hypothermia are additive, and that reduction in myocardial ischemia as evidenced by a reduction in peak PmCO2 correlated with improvement in ventricular performance in the post arrest period and with preservation of myocardial structure.
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19
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Effects of procaine-induced cardioplegia on myocardial ischemia, myocardial edema, and postarrest ventricular function. J Thorac Cardiovasc Surg 1978. [DOI: 10.1016/s0022-5223(19)39604-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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20
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Kärköla P, Saarela E, Tuononen S, Pokela R, Nuutinen L, Kairaluoma MI, Larmi TK. Intraoperative changes in coronary resistance during aortic valve replacement. Ann Thorac Surg 1978; 25:407-12. [PMID: 646510 DOI: 10.1016/s0003-4975(10)63575-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Coronary vascular resistance was investigated in 10 patients undergoing aortic valve replacement using continuous constant-pressure coronary perfusion at 32 degrees C. After coronary flow was initiated, resistance was low but increased steadily until it reached a certain resting level. The plateau was attained faster after a short period of anoxia than after a longer period. The initial postischemic resistance was dependent on the duration preceding anoxia, being of the same magnitude after short and moderate periods of anoxia but significantly higher after a long period. This resistance difference between the groups lasted for the whole perfusion. The total coronary resistance and flow reached a plateau in 30 minutes, while resistance increased threefold but flow decreased to half of the initial postanoxia flow. Our results indicate the importance of initiating coronary perfusion soon after aortic cross-clamping to avoid increase in the initial vascular resistance and subsequent inadequate myocardial flow.
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Case RB, Felix A, Wachter M, Kyriakidis G, Castellana F. Relative effect of CO2 on canine coronary vascular resistance. Circ Res 1978; 42:410-8. [PMID: 624148 DOI: 10.1161/01.res.42.3.410] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We determined the effect of alterations in coronary arterial PCO2 on coronary vascular resistance (CVR) at a constant coronary sinus (CS) PO2 and the effect of coronary arterial PO2 variation on CVR at a constant CS PCO2. A linear but opposing effect on CVR was found for both gases. The sensitivity of CVR to O2 change, represented as CVR/CS PO2, was approximately twice that of the ratio CVR/CS PCO2. (0.0852 +/- 0.006 vs. -0.0362 +/- 0.005). The entire range of CVR variation obtainable through CO2 variation was as great as that resulting from O2 variation. During randomized variation of O2 and CO2, CVR can be mathematically related in a multiple linear expression to CS PO2 and CS PCO2.
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Komoto Y, Kawakami S, Kasai T, Yamane Y. A new approach in evaluating the hemodynamics of ischemic legs by mass spectrometry: a preliminary report. Angiology 1977; 28:568-77. [PMID: 883687 DOI: 10.1177/000331977702800810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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23
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24
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Hicks G, Hill A, DeWeese J. Monitoring of midmyocardial and subendocardial pH in normal and ischemic ventricles. J Thorac Cardiovasc Surg 1976. [DOI: 10.1016/s0022-5223(19)40090-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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25
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Khuri SF, Brawley RK, O'Riordan JB, Donahoo JS, Pitt B, Gott VL. The effect of cardiopulmonary bypass perfusion pressure on myocardial gas tensions in the presence of coronary stenosis. Ann Thorac Surg 1975; 20:661-70. [PMID: 1212000 DOI: 10.1016/s0003-4975(10)65759-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Mass spectrometry was utilized to determine myocardial gas tensions in dogs subjected to cardiopulmonary bypass. Myocardial ischemia occurred in animals with normal coronary arteries when cardiopulmonary bypass perfusion pressure fell 40 to 60 mm Hg below the mean aortic pressure measured prior to bypass. Myocardial ischemia did not occur, or could be eliminated when present, if cardiopulmonary bypass perfusion pressure was maintained near prebypass mean aortic pressure. In animals with constricted circumflex coronary arteries, the adverse effect of low perfusion pressure on myocardial metabolism during cardiopulmonary bypass was found to be more severe in areas of myocardium supplied by the stenotic coronary artery. It is concluded that maintenance of cardiopulmonary bypass perfusion pressure near the level of preoperative mean aortic pressure will help prevent myocardial ischemia during operation; particularly in patients with coronary artery disease.
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26
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Hedenstierna G, Schildt B. Tissue PO2 measured in man by an implanted latex rubber tube. Acta Anaesthesiol Scand 1975; 19:370-6. [PMID: 1211076 DOI: 10.1111/j.1399-6576.1975.tb05198.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A latex rubber tube easily permeable to O2 was implanted in a triceps muscle of six volunteers. Seven days later, PO2 in muscle tissue (PtO2) was measured repeatedly by filling the tube with saline. After a 2-minute equilibration, the saline was sampled in a glass capillary and its PO2 measured by polarographic technique. PaO2 and venous oxygen tension (PvO2) were measured simultaneously. Measurements were performed under four conditions: (1) air breathing, (2) breathing 100% O2, (3) breathing 14% O2, and (4) 50 Warm exercise. During (1) breathing air PaO2 was on an average 90 mmHg, PvO2 36 MMHg and PtO2 40 mmHg. During (2) PaO2 reached 570 mmHg in 2 min, PvO2 rose slightly and PtO2 increased to 80-90 mmHg in 30-40 min. During (3) PaO2 fell rapidly to 45 mmHg and PtO2 decreased from 40 to 30 mmHg in 8 min. During (4) PaO2 did not change, PvO2 decreased slightly and PtO2 fell to approximately 30 mmHg within 2-4 min. The interindividual scatter was of equal magnitude in tissue and blood. A PtO2 higher than PvO2 during oxygen breathing and less than PvO2 during hypoxia and physical exercise is explained by the existence of oxygen gradients in the extravascular space. The present technique proved to be simple despite a 1-week delay before measurements. There were no complications, and no discomfort was complained of. Thus, the latex rubber tube seems suitable for clinical use.
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28
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MacGregor DC, Wilson GJ, Holness DE, Lixfeld W, Yasui H, Tanaka S, Silver MD, Gunstensen J. Intramyocardial carbon dioxide tension. J Thorac Cardiovasc Surg 1974. [DOI: 10.1016/s0022-5223(19)41693-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Brown AH, Braimbridge MV, Darracott S, Chayen J, Kasap H. An experimental evaluation of continuous normothermic, intermittent hypothermic, and intermittent normothermic coronary perfusion. Thorax 1974; 29:38-50. [PMID: 4274933 PMCID: PMC470402 DOI: 10.1136/thx.29.1.38] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Hedley Brown, A., Braimbridge, M. V., Darracott, Sally, Chayen, J., and Kasap, H. (1974).Thorax, 29, 38-50. An experimental evaluation of continuous normothermic, intermittent hypothermic, and intermittent normothermic coronary perfusion. Coronary perfusion and hypothermia both have disadvantages, and excellent clinical results are obtained without them, though short operations, spontaneous cooling of unperfused hearts, hyperglycaemia, heparinization, and young and cyanotic subjects may allow more tolerance of ischaemia. Functional, macroscopic, histological, ultrastructural, chemical, and metabolic evidence of the inadvisability of ischaemia, especially of hypertrophied hearts, abounds, though statistical support and histochemical proof are lacking. Isovolumic function tests permit accurate assessment of compliance. Succinic dehydrogenase distribution is the most relevant enzyme assay of myocardial transport; freed phospholipids indicate cellular membrane disorganization. Adenosinetriphosphate response of myosin (myocardial ATP ase) is shown quantitatively by change of birefringence. Ventricular oedema may be detected by changes in weight. These tests were used to compare continuous normothermic, intermittent hypothermic, and intermittent normothermic perfusion over two hours in isolated, cross-perfused canine hearts. Isolated hearts are very sensitive to imperfections of maintenance, but cross-perfusion minimizes perfusion-induced deterioration. Normothermic continuously perfused hearts performed significantly better than intermittently perfused hearts, among which cooled hearts functioned better than normothermic hearts after two hours. Succinic dehydrogenase and acid haematein tests showed significant benefit from cooling during intermittent perfusion. The experimental preparation and techniques of assessment proved sensitive enough to demonstrate these differences, though cooling preserved cellular enzymes better than it did function. This work gives histochemical and statistical support to existing evidence that intermittent ischaemia for two hours can be ameliorated by moderate hypothermia but is not as effective for myocardial maintenance as constant perfusion with normal blood.
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Furuse A, Brawley RK, Gott VL. Effects of isoproterenol, l-norepinephrine, and glucagon on myocardial gas tensions in animals with coronary artery stenosis. J Thorac Cardiovasc Surg 1973. [DOI: 10.1016/s0022-5223(19)40721-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Kivisaari J, Niinikoski J. Use of silastic tube and capillary sampling technic in the measurement of tissue PO 2 and PCO 2 . Am J Surg 1973; 125:623-7. [PMID: 4699206 DOI: 10.1016/0002-9610(73)90149-9] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Mendler N, Schuchhardt S, Sebening F. Measurement of intramyocardial oxygen tension during cardiac surgery in man. RESEARCH IN EXPERIMENTAL MEDICINE. ZEITSCHRIFT FUR DIE GESAMTE EXPERIMENTELLE MEDIZIN EINSCHLIESSLICH EXPERIMENTELLER CHIRURGIE 1973; 159:231-8. [PMID: 4687013 DOI: 10.1007/bf01851548] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Manley JC, Johnson WD. Effects of surgery on angina (pre- and postinfarction) and myocardical function (failure). Circulation 1972; 46:1208-21. [PMID: 4642308 DOI: 10.1161/01.cir.46.6.1208] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
With the advent of direct bypass surgery, the dramatic clinical responses in some patients has been followed by enormous enthusiasm in many centers. Surgical technics have advanced to such a point that nearly all patients with obstructive coronary disease could have the obstructions bypassed to one or many areas. Criteria for evaluating surgery include mortality, operative infarction rate, patency of grafts, clinical response, and stress testing. Many reports fail to correlate results with angiographic studies of vein function and with completeness of revascularization. When cine studies are performed, a good correlation exists between patent veins and relief of angina and improved stress response. Different patterns of response to stress, sometimes independent of relief of angina, are obtained depending on the completeness of revascularization. Predictable relief of angina is found if revascularization is complete. At times dramatic, but much less predictable, relief of failure (improved ventricular function) follows revascularization. Angina is a valuable aid in selecting some patients for surgery. Stress testing (bicycle ergometry) can now define general groups of patients who are likely, and who are not likely, to show improved myocardial response to stress after surgery. These studies also demonstrate the need for the surgeon to provide complete revascularization whenever possible. The criteria for selection for surgery of patients with symptoms of gross heart failure remain unclear. While revascularization technics could be technically applied to nearly all coronary patients, present methods are unable accurately to define who really needs the surgery and, equally important, which hearts will respond once revascularization is completed.
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