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Biomedical subjects

S Slogoff

Publications and source records attributed to S Slogoff.

At least 37 records · Page 2Linked to original sources
PubMed1990

Stable rightward shifts of the oxyhemoglobin dissociation curve induced by encapsulation of inositol hexaphosphate in red blood cells using electroporation.

Rightward shifts of 50-100% of the P50 values in the oxygen dissociation curve of intracellular hemoglobin are obtained after encapsulation of inositol hexaphosphate in mouse and dog red blood cells (RBC) by electroporation. Life spans of mouse RBC-myo-inositol hexaphosphate in circulation are unchanged from the normal RBC values.

Allosteric Regulation↗
PubMed1990

Role of perfusion pressure and flow in major organ dysfunction after cardiopulmonary bypass.

The role of perfusion pressure and flow during cardiopulmonary bypass with moderate hypothermia and hemodilution in the development of new postoperative renal or clinically apparent cerebral dysfunction was examined in 504 adults. Cardiopulmonary bypass flow was targeted at greater than 40 mL.kg-1.min-1 and pressure at greater than 50 mm Hg. Flows and pressures less than target occurred in 21.6% and 97.1% of patients, respectively. Fifteen patients (3.0%) suffered new renal and 13 (2.6%) new central nervous system dysfunction. Low pressure or flow during cardiopulmonary bypass, expressed in absolute values or in intensity-duration units, were not predictors of either adverse outcome. Multivariate analysis identified use of postoperative intraaortic balloon counterpulsation (p less than 10(-6], excessive blood loss in the ICU (p less than 10(-4], need for vasopressors before cardiopulmonary bypass (p less than 10(-4], postoperative myocardial infarction (p less than 10(-3], emergency reoperation (p less than 0.002), excessive postoperative transfusion (p less than 0.02), and chronic renal disease (p less than 0.03) as independent predictors of postoperative renal dysfunction. Independent predictors of postoperative central nervous system dysfunction were cardiopulmonary resuscitation in the intensive care unit (p less than 10(-6], intracardiac thrombus or valve calcification (p less than 0.02), and chronic renal disease (p less than 0.03). Age greater than 65 years (40.7% of patients) did not predict either outcome. We conclude that failure of the native circulation during periods other than cardiopulmonary bypass rather than the flows and pressures considered here is the major cause of renal and clinically apparent central nervous system dysfunction after cardiac operations.

Adult↗
PubMed1990

Incidence of perioperative myocardial ischemia detected by different electrocardiographic systems.

To determine the extent to which different electrocardiographic systems account for differences in reported incidence of perioperative myocardial ischemia, the authors simultaneously recorded in 109 patients undergoing coronary artery bypass grafting (CABG) the V5 or modified CM5 lead on five ECG systems by means of a specially constructed common V5 lead. The systems included a Spacelabs Alpha 14 Model Series 3200 ECG Cardule at bandwidths of 0.05-125 Hz and 0.5-30 Hz (a typical operating room monitor), a Marquette Electronics MAC II ECG at 0.05-40 Hz and 0.05-100 Hz (a standard ECG), and a Del Mar Holter recorder at 0.1-100 Hz. Relative ST-segment position and incidence of new ischemia compared to the preoperative ECG were determined in 109 sets of preinduction traces and 877 sets of intraoperative traces. ST-segment position on the three recording systems conforming with the American Heart Association (AHA) low-frequency response recommendations (0.05 Hz) were similar. Compared to the standard ECG, ST-segment position on the Spacelabs at 0.5-30 Hz was consistently more negative. Displacement on the Holter was consistently less negative and less positive. By the 0.1-mV displacement criterion for diagnosis of myocardial ischemia on any one ECG system, 16.5% of patients on arrival and 32.1% of patients intraoperatively suffered new myocardial ischemia. Based on the operating room monitor, arrival and intraoperative ischemia were present in 15.6 and 27.5% of patients, respectively. Ischemia at the same periods was less frequent by the standard ECG system (5.5 and 12.8%, respectively) and least frequent by the Holter recorder (4.6 and 8.3%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Artery Bypass↗
PubMed1989

Randomized trial of primary anesthetic agents on outcome of coronary artery bypass operations.

To examine the role of primary anesthetic agent on outcome of coronary artery bypass grafting operations, 1,012 patients were prospectively randomized to receive enflurane (257), halothane (253), isoflurane (248), or sufentanil (254). Except for administration of the primary anesthetic, anesthesia management was standardized for all patients. The randomized groups did not differ in demographic characteristics, extent of coronary artery disease, chronic antianginal therapy, hemodynamic characteristics including new myocardial ischemia at arrival to the operating room, and surgical characteristics that might influence the rate of postoperative myocardial infarction or death. From anesthetic induction to start of cardiopulmonary bypass, new ST segment depression appeared in 310 (30.4%) patients and was not different among primary anesthetic groups (28.0-33.5%). Similarly, the incidence of postoperative myocardial infarction (3.6-4.7%) and death (1.2-2.4%) was not different. Although intraoperative hypotension was twice as common in patients receiving any volatile anesthetic and hypertension twice as common with sufentanil, tachycardia (greater than or equal to 110 bpm) was not related to any primary anesthetic (4.3-9.1%) and was the only hemodynamic abnormality significantly related to intraoperative ischemia. The strongest predictor of intraoperative ischemia was ischemia on arrival to the operating room. The authors postulate that approximately 90% of new myocardial ischemia observed during anesthesia is the manifestation of silent ischemia observed in patients before operation and only 10% is related to anesthetic management. They conclude that, despite differences in the hemodynamic consequences of the primary anesthetics studied, none of the primary anesthetics influenced outcome and the primary role of the anesthesiologist in management of these patients is control of heart rate.

Adult↗
PubMed1988

Does chronic treatment with calcium entry blocking drugs reduce perioperative myocardial ischemia?

To examine the role of chronic calcium entry blocking drug administration on perioperative myocardial ischemia and, specifically, the frequency of hemodynamically unrelated ischemia, the authors studied 444 patients undergoing coronary artery bypass operations. Before induction of anesthesia, 119 patients who chronically took calcium entry blocking drugs received nifedipine 20 mg or diltiazem 60 mg orally, 74 received calcium entry and beta adrenergic blocking drugs, 71 received beta blocking drugs only, and 180 received neither. New ischemia occurred in 208 (46.8%) patients; 55 at arrival to the operating room, 86 only after induction, and 67 separately during both periods. Two-thirds of all ischemia was not related to extremes of heart rate or blood pressure; this type was not less frequent in patients receiving calcium entry blocking drugs. Ischemia did occur less frequently in the two patient groups receiving beta adrenergic blocking drugs (34% vs. 53%), a result of less tachycardia both on arrival (3.4% vs. 15.4%) and during anesthesia, when peak heart rate exceeded 109 bpm in only one of 145 beta-blocked patients compared to 29 of 299 not receiving beta blocking drugs. While ischemia appeared during anesthesia in 34.5% of all patients, its incidence was doubled (63%) when heart rate was greater than or equal to 110 bpm. At lower heart rates, the incidence of ischemia did not differ among groups. With respect to all types of ischemia, patients receiving calcium entry blocking drugs only were indistinguishable from those receiving no antianginal therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1988

The overstated risk of preoperative hypokalemia.

To examine the relation between preoperative hypokalemia and frequency of intraoperative arrhythmias, Holter monitoring was employed in 447 patients undergoing major cardiac or vascular operations, the group at greatest risk for life-threatening arrhythmias. Based on serum potassium levels measured immediately before surgery, 57% of patients were normokalemic (greater than or equal to 3.6 mEq/L), 34% hypokalemic (3.1-3.5 mEq/L), and 9% severely hypokalemic (less than or equal to 3.0 mEq/L). No arrhythmia occurred at any time in 63% of patients and minor arrhythmias (premature atrial and occasional premature ventricular contractions) occurred in 16%. Frequent or complex ventricular ectopy appeared before and during operation in 92 patients (21%) but was not related to preoperative potassium level or history of long-term diuretic therapy. Frequent and complex ventricular arrhythmias were more common in patients with a history of long-term digoxin therapy or congestive heart failure. Even among these patients, hypokalemia or diuretic therapy did not increase the incidence or severity of ectopy. These data fail to support the common practice of delaying operation for acute potassium replacement in patients whose preoperative serum potassium is less than normal, even in the presence of cardiovascular disease.

Adult↗
PubMed1987

Venous admixture to radial artery blood samples during cardiopulmonary bypass.

The possibility that venous blood could be withdrawn through a radial artery cannula when venous pressure is high was examined in 30 patients during cardiopulmonary bypass for coronary artery bypass operation. Progressive desaturation of radial artery blood occurred when venous pressure was equal to arterial pressure. Desaturation not only increased with duration of venous obstruction but also occurred immediately if the arterial tree was emptied after occlusion. We believe that these observations result from the transcapillary aspiration of deep venous blood and may produce a potential source of error in measuring arterial oxygen tension during cardiopulmonary resuscitation, cardiac tamponade, and profound right heart failure, as well as cardiopulmonary bypass.

Arm↗
PubMed1987

Validity of scoring 'dangerous answers' on a written certification examination.

The American Board of Anesthesiology (ABA) investigated the possibility that selection of a disproportionately high number of incorrect "dangerous answers" by candidates who would otherwise pass the board's written certification examination might relate to dangerous clinical practice by the candidates. In that case, scoring the examination for dangerous answers would provide an alternate scoring method. Twenty-nine multiple-choice questions in the 1983 written examination were identified by a panel of judges as containing incorrect answers with "truly, not potentially" dangerous consequences. The 1,036 candidates who passed the 1983 examination selected an average of 1.6 dangerous answers, and the 1,413 who failed the examination selected an average of 3.4 (p less than .001). Ninety-two candidates who passed and who selected four or more dangerous answers were tracked through the certification process to learn whether labeling them as "smart but dangerous" was justified. Reports of their clinical competence from their residency programs did not relate dangerous behavior for any of these candidates. The 86 of these 92 candidates who subsequently took the ABA oral examination had pass rates that were identical to those of all candidates in 1983 and that were completely independent of the candidates' absolute and relative frequency of choosing dangerous answers. It is concluded that selection of dangerous answers in a multiple-choice test is the result of lack of information rather than a purposeful action and implementation of the scoring system for dangerous answers would likely be unjustified and unfairly punitive.

Achievement↗
PubMed1987

Protecting the brachial plexus during median sternotomy.

Injury to the brachial plexus was prospectively assessed in 335 patients undergoing median sternotomy for cardiac operation. All patients were placed in the hand-up position (elbows elevated, arms abducted 90 degrees, and elbows flexed) after right internal jugular vein cannulation (23 cannulation attempts were bilateral). Twenty-eight patients had new upper extremity complaints after the operation, of whom 16 (4.8%) had symptoms considered related to injury of the brachial plexus: one with generalized weakness of the left arm, six with localized weakness, pain, or paresthesia plus objective hypesthesia or weakness, and nine with paresthesias but no objective signs. Four injuries were right sided, four left sided, and eight bilateral. At the time of discharge, 15 of 16 were symptom free and the patient with generalized weakness was rapidly improving. Postoperative plexopathy was not related to degree of sternal retraction, dissection of the internal mammary artery, or cannulation of the internal jugular vein. We believe the low incidence and benign course of brachial plexus problems in these patients resulted from careful sternal retraction and use of the hands-up position. Finally, our data do not support internal jugular cannulation as a major cause of plexus injuries after median sternotomy.

Brachial Plexus↗
PubMed1986

Addition of papaverine to cardioplegia does not reduce myocardial necrosis.

In a randomized, double-blind prospective study involving 495 patients, we investigated whether the addition of papaverine, 60 mg, to our existing regimen of cold cardioplegia would reduce myocardial necrosis during elective coronary artery bypass operations. Twenty-one (4.2%) patients sustained acute postoperative myocardial infarctions (MI), and 7 (1.4%) died during hospitalization. Neither MI nor death was related to papaverine supplementation. Among 469 patients without postoperative MI, levels of the myocardial-specific isoenzyme of creatine phosphokinase measured 10 hours after aortic cross-clamping were related to ischemic cross-clamp time, but not to papaverine supplementation of cardioplegia. At declamping after completion of distal anastomoses, ventricular fibrillation was more common after cardioplegia without papaverine (32% versus 9%). No other differences between the two groups were found in intraoperative and postoperative hemodynamics, difficulty of weaning from bypass, or postoperative volume requirements. We identified three risk factors for postoperative MI: ECG evidence of new ischemia prior to bypass, unusual technical difficulty with distal anastomoses for the surgeon, and prolonged time of ischemia. We conclude that addition of papaverine to our cardioplegia regimen did not affect outcome or nonspecific myocardial necrosis.

Clinical Trials as Topic↗
PubMed1986

Neuropsychiatric complications after cardiopulmonary bypass: cerebral protection by a barbiturate.

The authors prospectively investigated the ability of thiopental to decrease neuropsychiatric complications as a consequence of open-ventricle operations requiring cardiopulmonary bypass. Eighty-nine randomly assigned patients received sufficient thiopental to maintain electroencephalographic silence throughout the period from before atrial cannulation to termination of bypass. These patients received an average of 39.5 mg/kg of thiopental, while 93 control patients received only fentanyl. On the first postoperative day, five thiopental (5.6%) and eight control (8.6%) patients exhibited clinical neuropsychiatric abnormalities. By the tenth postoperative day, all neuropsychiatric dysfunction had resolved in the thiopental group but persisted in seven (7.5%) control patients (P less than 0.025). The incidence of complications was significantly related to calcification of replaced valves, aortic valve replacement, advanced age, and prolonged bypass, but not to low blood pressure during perfusion. The authors believe their data are consistent with embolism as the most important cause of sensory-motor neurologic dysfunction following cardiopulmonary bypass. The data also provide evidence that thiopental in sufficient dosage can reduce the clinical consequences of these events. This is the first demonstration of cerebral protection by a barbiturate in humans.

Age Factors↗
PubMed1985

Does perioperative myocardial ischemia lead to postoperative myocardial infarction?

To determine if a relationship exists between perioperative myocardial ischemia (ST segment depression greater than or equal to 0.1 mV) and postoperative myocardial infarction (PMI), nonparticipating observers recorded all ECG, hemodynamic, and other events between arrival of patients in the operating room and onset of cardiopulmonary bypass during 1,023 elective coronary artery bypass operations (CABG). The roles of preoperative patient characteristics, quality of the operation limited by disease as rated by the surgeon and duration of ischemic cardiac arrest as risk factors for PMI also were quantified. ECG ischemia occurred in 36.9% of all patients, with almost half the episodes occurring before induction of anesthesia. PMI was almost three times as frequent in patients with ischemia (6.9% vs. 2.5%) and was independent of when ischemia occurred. Ischemia was related significantly to tachycardia but not hypertension nor hypotension and was frequent in the absence of any hemodynamic abnormalities. The anesthesiologist whose patients had the highest rate of tachycardia and ischemia had the highest rate of PMI. Although neither single nor multiple preoperative patient characteristics related to PMI, suboptimal quality of operation and prolonged ischemic cardiac arrest increased the likelihood of PMI independent of the occurrence of myocardial ischemia. The authors conclude that perioperative myocardial ischemia is common in patients undergoing CABG, occurs randomly as well as in response to hemodynamic abnormalities, and is one of three independent risk factors the authors identified as related to PMI. PMI is unrelated to preoperative patient characteristics such as ejection fraction and left main coronary artery disease, and its frequency will relate primarily to perioperative management rather than patient selection.

Anesthesia↗
PubMed1984

Heart block after coronary artery bypass--effect of chronic administration of calcium-entry blockers and beta-blockers.

We evaluated risk of heart block after cardiopulmonary by-pass (CPB) in patients with normal conduction undergoing coronary artery bypass grafting who chronically received calcium-entry blockers, beta-blockers, or combined therapy. Before CPB, calcium-entry blockers alone produced an increase in P-R intervals but no change in heart rate; calcium-entry blocker effects were undetectable after CPB, beta-Blockers alone or with calcium-entry blockers produced lower heart rates and longer P-R intervals throughout the entire perioperative period when compared to no therapy (control) or calcium-entry blockers alone. Complete heart block did not occur; one control patient had transient second degree block after CPB. First degree block appeared transiently in 5% of the patients after anesthetic induction and in 15% on emergence from CPB, but was unrelated to drug therapy. We conclude that chronic calcium-entry blocker therapy has minimal effects on conduction perioperatively; beta-blocker effects persist for up to 10 hr after CPB; and the risk of heart block with either drug or combination is low and should not be a factor in their continued administration preoperatively.

Adrenergic beta-Antagonists↗
PubMed1983

On the safety of radial artery cannulation.

The frequency of complications following radial artery cannulation for monitoring purposes was determined in 1,699 cardiovascular surgical patients and in 83 patients in whom cannulation was performed in another artery after failure at the radial site. Patients were examined and radial artery flow determined by a Doppler technique 1 day and 7 days after decannulation. Although partial or complete radial artery occlusion after decannulation occurred in more than 25% of the patients, no ischemic damage to the hand or disability occurred in any patient. Neither duration of cannulation nor the size or material of the cannulas were determinants of abnormal flow. Abnormal flow was significantly related to female sex, the presence of hematoma, and to the use of extracorporeal circulation. The radial arteries of 16 patients whose results of Allen's test were abnormal were cannulated and no abnormal flow or ischemia followed. In 22 patients, the ulnar artery was cannulated after multiple punctures of the ipsilateral radial artery and no ischemia followed. We conclude that in the absence of peripheral vascular disease, the Allen's test is not a predictor of ischemia of the hand during or after radial artery cannulation, that when decreased or absent radial artery flow follows cannulation it is of no clinical consequence, and that radial artery cannulation is a low-risk high-benefit monitoring technique that deserves wide clinical use.

Adult↗
PubMed1982

Etiologic factors in neuropsychiatric complications associated with cardiopulmonary bypass.

A prospective study of 204 patients undergoing operations requiring cardiopulmonary bypass was undertaken to determine the incidence and etiologic factors leading to postperfusion cerebral dysfunction and to determine whether pretreatment with thiopental, 15 mg/kg, would reduce the incidence. Patients were randomly assigned to a control (diazepam) or study (thiopental) group and were treated identically except for the drug administered. Patients were examined neurologically on the 1st and 4th postoperative day and a psychometric test was administered on the 4th day. Although fewer neuropsychiatric complications were present in patients given thiopental, the difference was not significant. The overall incidence of cerebral dysfunction attributable to cardiopulmonary bypass alone was 16.2% for transient and 6.4% for persistent dysfunction (present at the 10th postoperative day). The incidence of postoperative cerebral dysfunction was more than twice as high in patients undergoing intracardiac than in patients having extracardiac operations and more than 4 times as high in patients more than 60 years of age than in younger patients. Perfusion pressure less than 50 torr with hematocrit less than 30% was not related to development of postoperative cerebral dysfunction. The data suggest that air or particulate emboli originating within the heart or aorta are the major causes of postbypass cerebral dysfunction.

Adult↗