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Sharma AD, Parmley CL, Sreeram G, Grocott HP. Peripheral nerve injuries during cardiac surgery: risk factors, diagnosis, prognosis, and prevention. Anesth Analg 2000; 91:1358-69. [PMID: 11093980 DOI: 10.1097/00000539-200012000-00010] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Grocott HP, Scales G, Schinderle D, King K. A new technique for lung isolation in acute thoracic trauma. THE JOURNAL OF TRAUMA 2000; 49:940-2. [PMID: 11086788 DOI: 10.1097/00005373-200011000-00023] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kilts JD, Gerhardt MA, Richardson MD, Sreeram G, Mackensen GB, Grocott HP, White WD, Davis RD, Newman MF, Reves JG, Schwinn DA, Kwatra MM. Beta(2)-adrenergic and several other G protein-coupled receptors in human atrial membranes activate both G(s) and G(i). Circ Res 2000; 87:705-9. [PMID: 11029407 DOI: 10.1161/01.res.87.8.705] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cardiac G protein-coupled receptors that couple to Galpha(s) and stimulate cAMP formation (eg, beta-adrenergic, histamine, serotonin, and glucagon receptors) play a key role in cardiac inotropy. Recent studies in rodent cardiac myocytes and transfected cells have revealed that one of these receptors, the beta(2)-adrenergic receptor (AR), also couples to the inhibitory G protein Galpha(i) (activation of which inhibits cAMP formation). If beta(2)ARs could be shown to couple to Galpha(i) in the human heart, it would have important ramifications, because levels of Galpha(i) increase with age and in failing human heart. Therefore, we investigated whether beta(2)ARs in the human heart activate Galpha(i). By photoaffinity labeling human atrial membranes with [(32)P]azidoanilido-GTP, followed by immunoprecipitation with antibodies specific for Galpha(i), we found that Galpha(i) is activated by stimulation of beta(2)ARs but not of beta(1)ARs. In addition, we found that other Galpha(s)-coupled receptors also couple to Galpha(i), including histamine, serotonin, and glucagon. When coupling of these receptors to Galpha(i) is disrupted by pertussis toxin, their ability to stimulate adenylyl cyclase is enhanced. These data provide the first evidence that beta(2)AR and many other Galpha(s)-coupled receptors in human atrium also couple to Galpha(i) and that abolishing the coupling of these receptors to Galpha(i) increases the receptor-mediated adenylyl cyclase activity.
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MESH Headings
- Adenylate Cyclase Toxin
- Adenylyl Cyclases/metabolism
- Adrenergic beta-1 Receptor Antagonists
- Adrenergic beta-2 Receptor Antagonists
- Adrenergic beta-Agonists/pharmacology
- Aged
- Atrial Appendage/chemistry
- Atrial Appendage/metabolism
- Cell Membrane/chemistry
- Dobutamine/pharmacology
- Ethanolamines/pharmacology
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- Humans
- Isoproterenol/pharmacology
- Middle Aged
- Myocardial Contraction/physiology
- Pertussis Toxin
- Photoaffinity Labels
- Precipitin Tests
- Receptors, Adrenergic, beta-1/analysis
- Receptors, Adrenergic, beta-1/metabolism
- Receptors, Adrenergic, beta-2/analysis
- Receptors, Adrenergic, beta-2/metabolism
- Receptors, Cell Surface/analysis
- Receptors, Cell Surface/metabolism
- Receptors, Glucagon/metabolism
- Receptors, Histamine/metabolism
- Receptors, Serotonin/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Virulence Factors, Bordetella/pharmacology
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Sharma AD, Bittner HB, Sreeram G, Grocott HP, Slaughter TF. Interesting right ventricular transesophageal echocardiography findings. J Cardiothorac Vasc Anesth 2000; 14:617-9. [PMID: 11052452 DOI: 10.1053/jcan.2000.9495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Sharma AD, Grocott HP. Platelet transfusion reactions: febrile nonhemolytic reaction or bacterial contamination? Diagnosis, detection, and current preventive modalities. J Cardiothorac Vasc Anesth 2000; 14:460-6. [PMID: 10972618 DOI: 10.1053/jcan.2000.7962] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chew ST, Newman MF, White WD, Conlon PJ, Saunders AM, Strittmatter WJ, Landolfo K, Grocott HP, Stafford-Smith M. Preliminary report on the association of apolipoprotein E polymorphisms, with postoperative peak serum creatinine concentrations in cardiac surgical patients. Anesthesiology 2000; 93:325-31. [PMID: 10910477 DOI: 10.1097/00000542-200008000-00008] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Renal dysfunction after cardiac surgery occurs in up to 8% of patients and is associated with major increases in morbidity, mortality, and cost. Genetic polymorphisms have been implicated as a factor in the progression of chronic renal disease, but a genetic basis for the development of acute renal impairment has not been investigated. The authors therefore tested the hypothesis that apolipoprotein E alleles are associated with different postoperative changes in serum creatinine after cardiac surgery. METHODS The authors performed a prospective observational study with use of data from 564 coronary bypass surgical patients who were enrolled in an ongoing investigation of apolipoprotein E genotypes and organ dysfunction at a university hospital between 1989-1999. Renal function was assessed among apolipoprotein E genotype groups by comparisons of preoperative (CrPre), peak in-hospital postoperative (CrMax) and perioperative change (DCr) in serum creatinine values. RESULTS The epsilon4 allele grouping (E2 = 2/2,2/3,2/4; E3 = 3/3; E4 = 3/4,4/4) was associated with a smaller increase in postoperative serum creatinine (perioperative change: E4, +0.17; E3, +0.26; E4, +0.27 mg/dl) and a lower peak postoperative creatinine than the epsilon2 and epsilon3 in univariate and multivariate analysis (peak in-hospital postoperative serum creatinine multivariate P = 0.015 vs. epsilon3, P = 0.038 vs. epsilon2). There was no difference in baseline creatinine among allele groups. CONCLUSIONS Inheritance of the apolipoprotein epsilon4 allele is associated with reduced postoperative increase in serum creatinine after cardiac surgery, compared with the epsilon3 or epsilon2 allele. This is the first report of a possible genetic basis for acute renal impairment. These data may contribute to renal risk stratification for cardiac surgery and raise questions regarding apolipoprotein E and the pathophysiology of acute renal injury.
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Sharma AD, Sreeram G, Erb T, Grocott HP, Slaughter TF. Leukocyte-reduced blood transfusions: perioperative indications, adverse effects, and cost analysis. Anesth Analg 2000; 90:1315-23. [PMID: 10825313 DOI: 10.1097/00000539-200006000-00010] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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van Wermeskerken GK, Lardenoye JW, Hill SE, Grocott HP, Phillips-Bute B, Smith PK, Reves JG, Newman MF. Intraoperative physiologic variables and outcome in cardiac surgery: Part II. Neurologic outcome. Ann Thorac Surg 2000; 69:1077-83. [PMID: 10800797 DOI: 10.1016/s0003-4975(99)01443-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND The impact of alterable physiologic variables on neurologic outcome after coronary artery bypass grafting procedures is unknown. The purpose of this study was to determine whether minimum intraoperative hematocrit, maximum glucose concentration, or mean arterial pressure during cardiopulmonary bypass influences risk-adjusted neurologic outcome after coronary artery bypass grafting. METHODS Outcome data from 2,862 patients undergoing coronary artery bypass grafting were merged with intraoperative physiologic data. A preoperative stroke risk index was calculated for each patient. Variables found significant by univariate logistic regression were tested in a multivariable model to determine association with outcome. RESULTS The incidence of stroke or coma in the study population was 1.3%. After controlling for stroke risk and bypass time, only an index of low mean arterial pressure during bypass retained a significant inverse association with outcome (p = 0.0304). CONCLUSIONS This study found no evidence that glucose concentration or minimum hematocrit are associated with major adverse neurologic outcome. The association between lower pressure during bypass and decreased incidence of stroke or coma persisted in all risk groups. This points to mechanisms other than hypoperfusion as the primary cause of neurologic injury associated with cardiac surgery.
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Mackensen GB, Grocott HP, Smith MS. An interesting finding during transesophageal echocardiographic assessment of the mitral valve. J Cardiothorac Vasc Anesth 2000; 14:227-8. [PMID: 10794350 DOI: 10.1016/s1053-0770(00)90026-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
The neurological complications of cardiac surgery are associated with significantly increased mortality, morbidity and resource utilization. The use of new surgical techniques, introduction of wider indications for surgery and increased public expectation has led to an increase in the average age of cardiac surgical patients and an increased incidence of repeat procedures. With these changes has come an increased risk of neurological complications. The likelihood of perioperative stroke varies between 1% and 5% in most published series and is dependent on a multitude of risk factors. Of these, patient age, aortic atheroma, symptomatic cerebrovascular disease, diabetes mellitus and the type of surgery appear to be most important. Cognitive deterioration after cardiac surgery is far more common, affecting as many as 80% of patients a few days after surgery and persisting in one-third. Despite an increase in the age of the cardiac surgical population, the reported incidence of cognitive dysfunction after cardiac surgery seems to have fallen in recent years. Whether this is a real phenomenon or the result of changes in the use of psychometric testing and the definition of cognitive decline remains unclear. Recognition that certain equipment, surgical practices and patient factors contribute to neurological morbidity has prompted 'neuroprotective' interventions. Some of these (e.g. arterial line filtration and alpha-stat management) have been shown to improve outcome. Despite these measures, a small number of patients will inevitably sustain cerebral injury during otherwise successful cardiac surgery. Although pharmacological neuroprotection may, in the future, offer some of these patients an improved outcome, it is unlikely that any single agent will prevent neurological injury. In the meantime, the CNS complications of cardiac surgery remain a fertile area of research.
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Mackensen GB, Nellgård B, Sarraf-Yazdi S, Dexter F, Steffen RP, Grocott HP, Warner DS. Post-ischemic RSR13 amplifies the effect of dizocilpine on outcome from transient focal cerebral ischemia in the rat. Brain Res 2000; 853:15-21. [PMID: 10627303 DOI: 10.1016/s0006-8993(99)02212-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In a recent study of focal cerebral ischemia in rats, pre-ischemic administration of the synthetic allosteric hemoglobin modifier RSR13 (2-[4-[[3,5-dimethylanilino) carbonyl] methyl] phenoxy]-2-methylproprionic acid) reduced cerebral infarct size when combined with the NMDA receptor antagonist dizocilpine (MK-801) but not when given alone. We hypothesized that post-ischemic RSR13 administration would enhance neuroprotection afforded by NMDA receptor antagonism in a rat model of transient middle cerebral artery occlusion (MCAO). Fasted normothermic Wistar rats underwent 75 min of temporary MCAO. At onset of reperfusion, rats randomly received: (1) 0.9% NaCl (vehicle) i.v. alone (n=16); (2) 0.9% NaCl+dizocilpine (0.25 mg/kg) i.v. (n=16); or (3) RSR13 (150 mg/kg)+dizocilpine (0.25 mg/kg) i.v. (n=17). Seven days later, neurologic deficit and cerebral infarct size were determined. Dizocilpine alone compared to vehicle reduced mean+/-S.D. subcortical (52+/-24 mm(3) vs. 122+/-64 mm(3), P=0.003) and cortical (35+/-35 mm(3) vs. 125+/-72 mm(3), P=0.00074) infarct volumes. When compared to dizocilpine alone, the combination of RSR13+dizocilpine further reduced subcortical (37+/-14 mm(3) vs. 52+/-24 mm(3), P=0. 034) and cortical (8+/-19 mm(3) vs. 35+/-35 mm(3), P=0.018) infarct size. RSR13+dizocilpine improved neurologic scores vs. either dizocilpine alone (P=0.0014) or vehicle (P=10(-7)). The combination of NMDA receptor antagonism and a RSR13 mediated rightward shift of the oxy-hemoglobin dissociation curve improved outcome from MCAO. Because this occurred after reperfusion, our results suggest that the post-ischemic brain continues to suffer from hypoperfusion defects, which are amenable to therapy by enhanced O(2) delivery. The results also support the concept that neuroprotective strategies, which combine drugs with different mechanisms of action, may yield cumulative benefits.
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Arrowsmith JE, Grocott HP, Newman MF. Neurologic risk assessment, monitoring and outcome in cardiac surgery. J Cardiothorac Vasc Anesth 1999; 13:736-43. [PMID: 10622661 DOI: 10.1016/s1053-0770(99)90132-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Garduno C, Chew S, Forbess J, Smith PK, Grocott HP. Persistent left superior vena cava and partial anomalous pulmonary venous connection: incidental diagnosis by transesophageal echocardiography during coronary artery bypass surgery. J Am Soc Echocardiogr 1999; 12:682-5. [PMID: 10441226 DOI: 10.1053/je.1999.v12.a98795] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Transesophageal echocardiography plays an important role in the intraoperative treatment of the heart surgery patient. Its utility in the description of both known and unexpected cardiac pathology is well established. We describe a patient with a previously undiagnosed partial anomalous pulmonary venous connection along with a persistent left superior vena cava scheduled for routine coronary artery bypass graft surgery (CABG).
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Garduno C, Chew S, Grocott HP. Microbubble intravenous contrast during transesophageal echocardiography: agitated 0.9% saline versus agitated 0.9% saline with benzyl alcohol. J Cardiothorac Vasc Anesth 1999; 13:513. [PMID: 10468277 DOI: 10.1016/s1053-0770(99)90251-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Sarraf-Yazdi S, Sheng H, Grocott HP, Bart RD, Pearlstein RD, Steffen RP, Warner DS. Effects of RSR13, a synthetic allosteric modifier of hemoglobin, alone and in combination with dizocilpine, on outcome from transient focal cerebral ischemia in the rat. Brain Res 1999; 826:172-80. [PMID: 10224294 DOI: 10.1016/s0006-8993(99)01233-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study examined the effect of a pharmacologically induced rightward shift in the partial pressure of oxygen at which 50% of hemoglobin is saturated (P50) on outcome from transient focal cerebral ischemia in the rat. Halothane anesthetized rats (n=20 per group) were given saline or a single 15-min infusion of 150 mg/kg RSR13 (2-[4-[[3,5-dimethylanilino) carbonyl]methyl]phenoxy]-2-methylproprionic acid) intravenously before or 30 min after onset of 75 min of middle cerebral artery filament occlusion (MCAO). Seven days later, severity of hemiparesis and cerebral infarct size were examined. RSR13 alone did not significantly improve outcome. Conscious normothermic rats (n=12 per group) were also given RSR13 (150 mg/kg) or 0.9% NaCl intravenously and subjected to 75 min of MCAO with 7 days of recovery. Again, RSR13 alone did not significantly reduce infarct size or improve neurologic score. A dose-response curve for dizocilpine (MK-801) was then constructed in conscious normothermic rats subjected to 75 min of MCAO. Dizocilpine (0.5 mg/kg i.v.) caused a 90% reduction in mean infarct size while 0.25 mg/kg reduced infarct size by 48%. Other rats were then subjected to 75 min of MCAO after being given dizocilpine (0.25 mg/kg i.v.; n=18) or RSR13 (150 mg/kg i.v. )+dizocilpine (0.25 mg/kg i.v.; n=15). RSR13+dizocilpine resulted in smaller cortical infarct volume (8+/-14 mm3 vs. 34+/-37 mm3, p<0.02) and total cerebral infarct volume (46+/-28 mm3 vs. 81+/-60 mm3, p<0. 05) compared to dizocilpine alone, respectively. We conclude that a pre-ischemic peak increase in P50 of approximately 25 mmHg alone is insufficient to reduce focal ischemic injury, but may be advantageous when used in conjunction with other neuroprotective agents.
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Grocott HP, Sheng H, Miura Y, Sarraf-Yazdi S, Mackensen GB, Pearlstein RD, Warner DS. The effects of aprotinin on outcome from cerebral ischemia in the rat. Anesth Analg 1999; 88:1-7. [PMID: 9895057 DOI: 10.1097/00000539-199901000-00001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
UNLABELLED The administration of aprotinin has been associated with a reduction in cardiac surgery-related stroke. Intrinsic neuroprotective properties of this drug have not been evaluated in laboratory outcome models of cerebral ischemia. The purpose of this study was to determine whether aprotinin exhibits neuroprotective effects against either global or focal cerebral ischemia in the rat. Fasted rats were administered aprotinin (30,000 or 60,000 KIU/kg) or vehicle (0.9% NaCl) IV before global ischemia (10 min bilateral carotid occlusion with mean arterial pressure 30 mm Hg) or focal ischemia (75 min of transient middle cerebral artery occlusion [MCAO]). Five days after global ischemia, the percentage of dead hippocampal CA1 neurons (mean +/- SD) was similar among the groups (small-dose aprotinin: 49+/-31, n = 15; large-dose aprotinin: 55+/-31, n = 13; vehicle: 47+/-31, n = 16; P = 0.74). After 7 days' recovery from MCAO, no difference among the groups was observed for either neurologic score (P = 0.99) or cerebral infarct volume (small-dose aprotinin: 136+/-80 mm3, n = 23; large-dose aprotinin: 132+/-101 mm3, n = 11; vehicle: 121+/-81 mm3, n = 21; P = 0.87). IMPLICATIONS Aprotinin offers no neuroprotection against either global or focal cerebral ischemia in the rat when administered as a single preischemic bolus.
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Weiss L, Grocott HP, Rosania RA, Friedman A, Newman MF, Warner DS. Case 4--1998. Cardiopulmonary bypass and hypothermic circulatory arrest for basilar artery aneurysm clipping. J Cardiothorac Vasc Anesth 1998; 12:473-9. [PMID: 9713741 DOI: 10.1016/s1053-0770(98)90206-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Miura Y, Grocott HP, Bart RD, Pearlstein RD, Dexter F, Warner DS. Differential effects of anesthetic agents on outcome from near-complete but not incomplete global ischemia in the rat. Anesthesiology 1998; 89:391-400. [PMID: 9710398 DOI: 10.1097/00000542-199808000-00016] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND It has been postulated that anesthetic agents that reduce cerebral metabolic rate will protect the brain against ischemia when electroencephalographic (EEG) activity is persistent, but will provide no protection when ischemia is severe enough to cause EEG isoelectricity. No outcome studies have addressed this issue. The authors studied anesthetic agents to determine if they provide differential effects on outcome from global cerebral ischemic insults that cause either an attenuated or isoelectric EEG. METHODS Fasted rats were subjected to either (1) incomplete ischemia (attenuated EEG; 20 min of mean arterial pressure [MAP] = 50 mmHg and bilateral carotid occlusion) or (2) near-complete ischemia (isoelectric EEG; 10 min of MAP = 30 mmHg and bilateral carotid occlusion) while anesthetized with 1.4% isoflurane, 1 mg x kg(-1) x min(-1) ketamine, or 25 microg x kg(-1) x h(-1) 70% nitrous oxide and fentanyl. The brain was maintained at normothermia during ischemia and for 22 h after ischemia. Five days later, hippocampal CA1 and cortical injury were measured. RESULTS There was no difference among anesthetic agents during incomplete ischemia for mean +/- SD percentage dead CA1 neurons (fentanyl, 38%+/-20%; isoflurane, 31%+/-10%; ketamine, 40%+/-19%; P = 0.38). During near-complete ischemia, there was a difference among anesthetic agents (fentanyl, 88%+/-9%; isoflurane, 37%+/-20%; ketamine, 70%+/-28%; P = 0.00008). Isoflurane was protective compared with fentanyl (P = 0.00007) and ketamine (P = 0.0061). There was no difference between fentanyl and ketamine (P = 0.143). Similar observations were made in the cortex. Neurologic function correlated with histologic damage. CONCLUSIONS Outcome from near-complete but not incomplete cerebral ischemia depended on the anesthetic agent administered during the ischemic insult.
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Grocott HP, Bart RD, Sheng H, Miura Y, Steffen R, Pearlstein RD, Warner DS. Effects of a synthetic allosteric modifier of hemoglobin oxygen affinity on outcome from global cerebral ischemia in the rat. Stroke 1998; 29:1650-5. [PMID: 9707208 DOI: 10.1161/01.str.29.8.1650] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Neuronal injury results from an insufficient supply of oxygen to the brain. This experiment examined whether a pharmacologically induced rightward shift of the partial pressure of oxygen at which 50% of hemoglobin is saturated (P50) would improve outcome from either incomplete and/or near-complete forebrain ischemia-induced hypoxia in the rat. METHODS For incomplete ischemia (attenuated electroencephalogram), fasted rats (n = 17 to 19 per group) were given a synthetic allosteric modifier of hemoglobin affinity for oxygen (RSR13; 150 mg/kg IV) before or immediately after 20 minutes of bilateral carotid occlusion combined with a decrease in mean arterial pressure to 40 mm Hg. For near-complete ischemia (isoelectric electroencephalogram), rats (n = 15 per group) were given RSR13 (150 mg/kg) at onset of reperfusion after 10 minutes of bilateral carotid occlusion combined with a decrease in mean arterial pressure to 30 mm Hg. In both experiments, control rats were given vehicle (0.9% NaCl IV) only. Outcome (defined as percent dead hippocampal CA1 neurons) was determined at 5 days after ischemia. RESULTS RSR13 (150 mg/kg) produced a 68% rightward shift of P50 (34+/-3 to 57+/-8 mm Hg). RSR13 reduced CA1 damage resulting from incomplete ischemia by 28% (P=0.02), but only when administered at the onset of reperfusion. RSR13 had no effect on outcome from near-complete ischemia. CONCLUSIONS A postischemic pharmacologically induced increase in P50 may improve outcome from incomplete global cerebral ischemia. More severe (near-complete) ischemia negates this benefit.
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Grocott HP, Croughwell ND, Amory DW, White WD, Kirchner JL, Newman MF. Cerebral emboli and serum S100beta during cardiac operations. Ann Thorac Surg 1998; 65:1645-9; discussion 1649-50. [PMID: 9647074 DOI: 10.1016/s0003-4975(98)00276-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND The glial protein S100beta has been used to estimate cerebral damage in a number of clinical settings. The purpose of this investigation was to determine the correlation between cerebral microemboli and S100beta levels during cardiac operations. METHODS Transcranial Doppler ultrasonography was used to measure emboli in the right middle cerebral artery. Emboli counts (n = 111) were divided into five time periods: (1) incision to aortic cannulation; (2) aortic cannulation to cross-clamp onset; (3) cross-clamp onset to cross-clamp release; (4) cross-clamp release to decannulation; and (5) decannulation to chest closure. The level of S100beta (n = 156) was measured at baseline, at the end of cardiopulmonary bypass, then 150 and 270 minutes after cross-clamp release. RESULTS The level of S100beta correlated with age, cardiopulmonary bypass time, cross-clamp time, and number of emboli at time period 2. Although cardiopulmonary bypass time was univariately associated with S100beta level, it became nonsignificant in a multivariable model that included age and cross-clamp time. CONCLUSIONS The correlation of S100beta level with emboli measured during cannulation (time period 2) supports the hypothesis that cannulation is a high-risk time period for cerebral injury.
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Croughwell ND, Reves JG, White WD, Grocott HP, Baldwin BI, Clements FM, Davis RD, Jones RH, Newman MF. Cardiopulmonary bypass time does not affect cerebral blood flow. Ann Thorac Surg 1998; 65:1226-30. [PMID: 9594842 DOI: 10.1016/s0003-4975(98)00113-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND A time-dependent decline in cerebral blood flow (CBF) has been reported in cardiac surgical patients despite stable pump flows and arterial carbon dioxide tension. Other studies have failed to support these hypothermic cardiopulmonary bypass (CPB) results, showing preservation of CBF during CPB. The purpose of the study was to define the influence of mildly hypothermic CPB duration on CBF. METHODS Cerebral blood flow was measured using xenon-133 washout and alpha-stat blood gas management during nonpulsatile CPB. Cerebral blood flow measurements were made after the initiation of CPB and near the end of bypass during pump flows of 2.4 L.min-1.m-2. RESULTS Fifty-two coronary artery bypass patients were studied. The average time between CBF measurements was 54 +/- 20 minutes (mean +/- standard deviation), with a range of 10 to 100 minutes. Temperature and arterial carbon dioxide tension were controlled: after the initiation of CPB, temperature was 35.5 degrees +/- 0.4 degree C and carbon dioxide tension was 37 +/- 2.8 mm Hg; whereas near the end of bypass temperature was 35.6 degrees +/- 0.5 degree C and carbon dioxide tension was 36 +/- 2.3 mm Hg. We found no correlation between CBF and time on CPB (p = 0.47; r = 0.101), in contrast to other studies suggesting that CPB duration may intrinsically affect CBF. CONCLUSIONS Our experimental results include the following: (1) during mildly hypothermic bypass, CBF does not decrease in relation to time and (2) cerebral flow-metabolism coupling is intact at 35 degrees C.
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Grocott HP, Smith MS, Glower DD, Clements FM. Endovascular aortic balloon clamp malposition during minimally invasive cardiac surgery: detection by transcranial Doppler monitoring. Anesthesiology 1998; 88:1396-9. [PMID: 9605702 DOI: 10.1097/00000542-199805000-00033] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Chew STH, Tardiff BE, Conlon PJ, White WD, Newman MF, Landolfo K, Grocott HP, Smith MS. APOLIPOPROTEIN E PHENOTYPE DOES NOT PREDICT RISK OF RENAL IMPAIRMENT AFTER CABG SURGERY. Anesth Analg 1998. [DOI: 10.1213/00000539-199804001-00057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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