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Biomedical subjects

R L Fisk

Publications and source records attributed to R L Fisk.

At least 19 recordsLinked to original sources
PubMed1987

Perioperative right heart failure: etiology and pathophysiology.

A considerable amount of literature has been devoted to compromise of the right ventricle in spontaneous myocardial infarction. Little information is available regarding disproportionate dysfunction of the right ventricle associated with cardiac operation and the recovery period therefrom. Recognition of the problem is of paramount importance, if support measures are to be implemented. A great deal has yet to be learned regarding the appropriate support for the acutely failing right ventricle. Much remains to be accomplished regarding the assessment of right ventricle reserve, defining the role of risk factors, and quantitating the value of measures to optimally protect the right ventricle from injury during the perioperative period. Recognizing that the integrity of the right ventricle can be altered by numerous preoperative, perioperative and postoperative factors will provide an enlightened disposition on the part of the surgical team. Awareness of these considerations in the planning and conduct of surgical procedures should reduce morbidity and mortality from perioperative right ventricular failure. The imposition of new or unexpected morbidity during operation on a relatively unrelated problem represents surgical imperfection. Appropriate effort toward minimizing insult of the right ventricle could result in significantly decreasing the incidence and severity of perioperative right ventricular failure before the impetus of the continuing clinical problem dictates improvement in techniques to more appropriately treat this frequently preventable problem.

Coronary Disease↗
PubMed1985

Acute right ventricular failure is caused by inadequate right ventricular hypothermia.

The hypothesis of this study was that inadequate right ventricular hypothermia contributes to the right ventricular dysfunction occasionally observed after cardiac operations. Dogs were placed on cardiopulmonary bypass, and 60 minute periods of hypothermic myocardial ischemia were imposed. Left ventricular temperature was always maintained at 15 degrees C and right ventricular temperatures were maintained at 15 degrees C (Group I, n = 8), 25 degrees C (Group II, n = 8), and 35 degrees C (Group III, n = 8). These temperatures were produced by infusion of hypothermic crystalloid cardioplegic solution and appropriate topical cooling and heating of the left and right ventricles, respectively. Multiple indices of ventricular function were obtained 15, 30, 45, and 60 minutes after bypass and compared to prebypass control values. In all Group I animals (left ventricular temperature = 15 degrees C, right ventricular temperature = 15 degrees C), postischemic indices of right ventricular function were not different from control values (p = NS). In Group II (left ventricular temperature = 15 degrees C, right ventricular temperature = 25 degrees C), two animals died 30 and 45 minutes after bypass, respectively, of right ventricular failure. In the other six animals in Group II, all indices of right ventricular function were significantly reduced (p less than 0.05) except for right ventricular systolic pressure. In Group III (left ventricular temperature = 15 degrees C, right ventricular temperature = 35 degrees C), two animals could not be weaned from cardiopulmonary bypass because of right ventricular akinesia. Six animals were weaned from bypass, but two died 15 minutes, one died 30 minutes, and one 45 minutes after bypass. Two animals lived 60 minutes, but all indices of right ventricular function were decreased. Failure to maintain right ventricular temperatures below 25 degrees C during 1 hour of cardiac ischemia in the dog can result in fatal right ventricular failure.

Animals↗
PubMed1984

Effect of intermittent infusions of glucose-containing crystalloid cardioplegic solution on myocardial tissue lactic acid and recovery of contractility.

The objective of this study was to determine the effects of single or intermittent infusions of cardioplegic solution with glucose (5 gm/L) or without glucose on myocardial tissue lactic acid and recovery of myocardial contractility following 80 minutes of total ischemia at 28 degrees C in the isolated, blood-perfused, beating rabbit heart. Ischemia without cardioplegia increased tissue lactic acid (6.79 mg/gm tissue) above the control value (0.9 mg/gm tissue), p less than 0.0025). Lactic acid following single infusions with (4.19 mg/gm tissue) or without glucose (3.67 mg/gm tissue) was significantly greater (p less than 0.0025) than tissue lactic acid following intermittent infusions with (1.06 mg/gm tissue) or without glucose (1.05 mg/gm tissue). Cardioplegic arrest in all cases significantly decreased tissue lactate accumulation when compared to arrest without cardioplegia (p less than 0.01). The decrease in myocardial contractility demonstrated when no cardioplegic protection was employed (86% recovery) was completely eliminated (100% recovery) with a single-bolus infusion of cardioplegic solution containing glucose (p less 0.025). Intermittent infusions of cardioplegic solution containing glucose (92% recovery) and single infusions without glucose (93% recovery) also improved recovery of contractility following ischemia, but the results were not statistically significant.

Animals↗
PubMed1983

Delayed recovery following hypothermic arrest in rabbit myocardium.

The purpose of this investigation was to determine the relationship between the duration of myocardial ischemia at 15 degrees C and the time required for the myocardium to recover maximum contractile function following the ischemia. The isolated blood perfused rabbit heart was used as a model of myocardial ischemia. Hearts from 22 New Zealand white rabbits were divided into four groups. In Group I seven hearts were subjected to 15 minutes of ischemia at 15 degrees C. In Group II five hearts were subjected to 30 minutes of ischemia at 15 degrees C. In Group III and IV the ischemia time was extended to 60 and 120 minutes, respectively. Following the ischemia each heart was reperfused at normothermia and papillary muscle contractility was measured and used as an index of myocardial recovery. Hearts in Group I recovered their maximum contractile function after an average of 22.5 minutes. Those in Groups II, III, and IV were fully recovered after 31.7, 38.2, and 45.5 minutes, respectively. The study indicates that the time required for the maximum recovery of myocardial contractility following myocardial ischemia increases at a decreasing rate with an increase in the duration of the ischemia at 15 degrees C.

Animals↗
PubMed1982

Asymmetrical myocardial hypothermia during hypothermic cardioplegia.

To evaluate the possibility of inadequate right ventricular protection during operation, the temperatures of the anterior myocardium of the right ventricle and the middle of the interventricular septum were compared at ten-minute intervals throughout the period of continuous coronary ischemia in 130 consecutive patients. Systemic temperature was lowered to 23 degrees C, using cardiopulmonary bypass. Cardiac arrest was induced by aortic cross-clamping and infusion of cold cardioplegic solution. Cold solution was reinfused as necessary to maintain septal temperatures at less than 20 degrees C. Despite the use of superior and inferior vena caval cannulation for control of venous return, it was more difficult to maintain the right ventricle at the desired degree of myocardial hypothermia than the left ventricle. The difference between left and right ventricular temperatures was as great as 19 degrees C. In 80% of the observations (n = 1,010), the right ventricle was warmer than the left ventricle. The most frequently occurring temperature differences (left ventricle minus right ventricle) were in the 2 degrees to 3 degrees C range. These data indicate that it is more difficult to maintain hypothermia in the right ventricle. Concern for the left ventricle alone may be misleading. An alarming degree of rewarming may occur in the right ventricle and thereby contribute to right ventricular dysfunction and unilateral right ventricular failure.

Body Temperature↗
PubMed1980

Expeditious location of the embedded proximal left anterior descending coronary artery.

Retrograde passage of an intraluminal coronary artery probe to the proximal segment of the anterior descending coronary artery facilitates location of the vessel at operation. No related complications have occurred in 18 patients in whom this maneuver was performed. This method reduces the required dissection time and the hazard involved when aortocoronary bypass to an embedded left anterior descending coronary artery is necessary.

Coronary Artery Bypass↗
PubMed1978

Hypothermic coronary perfusion for myocardial protection during aortocoronary bypass.

Numerous methods have been used in an attempt to prevent myocardial injury that results from the interruption of aortic flow during cardiac operations. The authors describe a relatively simple means of inducing cardioplegia during coronary bypass surgery by coronary perfusion with cold lactated Ringer's solution through the aortic root. When the results following the employment of hypothermic coronary perfusion for intraoperative cardioplegia were compared with those obtained without its use, the procedure was found to confer a degree of intraoperative myocardial protection and appeared to lead to a decrease in intraoperative myocardial infarction, subendocardial ischemia and intraoperative mortality.

Coronary Artery Bypass↗
PubMed1978

Myocardial protection during aortic valve replacement: normothermia versus hypothermia.

The operative results in 32 patients who underwent aortic valve replacement with aortic occlusion and normothermic myocardium (group 1) were compared with 54 similar patients in whom the myocardium was protected by hypothermic coronary perfusion through the aortic root (group 2). The operative mortality and the incidence of heart failure, subendocardial ischemia and myocardial infarction were the same in the two groups. The maximal concentrations of cardiac enzymes after operation in group 2 patients were significantly lower than those in group 1. The postoperative cardiac performance was significantly different in that only 5.6% of group 2 patients required inotropic agents after operation compared with 25% of group 1 patients. The patients in group 2 were easier to defibrillate after cardiopulmonary bypass.

Adult↗
PubMed1977

Hypothermic coronary perfusion for intraoperative cardioplegia.

Hypothermic asanguineous perfusion has been used to arrest 170 hearts at the beginning of 1/2 to 2 hours of intraoperative coronary ischemia. This method of producing cardioplegia has facilitated valve replacement and coronary artery bypass operations. Inadequate myocardial protection has not been experienced since we began using this method of arresting the heart for cardiac operations.

Adult↗
PubMed1977

Missile migration from lung to heart with delayed systemic embolization.

A bullet migrated from the heart to the left femoral artery in a youth ten days after he sustained a gunshot wound to the right chest. The bullet apparently traversed the pulmonary venous system at the time of the injury and lodged in the interior of the left ventricle. The production of an embolism in the systemic circulation was a delayed and unanticipated event.

Adolescent↗
PubMed1977

Accidental pneumatic rupture of the esophagus.

A case of accidental pneumatic rupture of the thoracic esophagus in a 6-year-old boy is reported. Early operation with transthoracic esophageal repair resulted in survival of the patient, and follow-up at 18 months has demonstrated normal esophageal function and anatomy. A search of the literature has yielded 11 similar cases.

Child↗
PubMed1976

Experience with the radial artery graft for coronary artery bypass.

Forty-eight radial artery grafts and 22 saphenous vein grafts in 37 patients undergoing coronary bypass procedures were studied early postoperatively. Most of the saphenous vein grafts were patent, but one-half of the radial artery grafts were occluded. Failure of the radial artery grafts could not be attributed to unfavorable runoff in the recipient vessels. Radial arteries carrying higher flows and those to vessels having more severe degrees of proximal stenosis occluded with a higher frequency. The radial artery should not be used for coronary bypass.

Aged↗