PubMed Health⌕ Search

Biomedical subjects

M Rosenbloom

Publications and source records attributed to M Rosenbloom.

At least 37 records · Page 2Linked to original sources

Haemodynamic instability and myocardial ischaemia during carotid endarterectomy: a comparison of propofol and isoflurane.

The purpose of this study was to compare two anaesthetic protocols for haemodynamic instability (heart rate (HR) or mean arterial pressure (MAP) < 80 or > 120% of ward baseline values) measured at one-minute intervals during carotid endarterectomy (CEA). One group received propofol/alfentanil (Group Prop; n = 14) and the other isoflurane/alfentanil (Group Iso; n = 13). Periods of haemodynamic instability were correlated to episodes of myocardial ischaemia as assessed by Holter monitoring (begun the evening before surgery and ceasing the morning of the first postoperative day). In Group Prop, anaesthesia was induced with alfentanil 30 micrograms.kg-1 i.v., propofol up to 1.5 mg.kg-1 and vecuronium 0.15 mg.kg-1, and maintained with infusions of propofol at 3-12 mg.kg-1.hr-1 and alfentanil at 30 micrograms.kg-1.hr-1. In Group Iso, anaesthesia was induced with alfentanil and vecuronium as above, thiopentone up to 4 mg.kg-1 and maintained with isoflurane and alfentanil infusion. Phenylephrine was infused to support MAP at 110 +/- 10% of ward values during cross-clamp of the internal carotid artery (ICA) in both groups. Emergence hypertension and/or tachycardia was treated with labetalol, diazoxide or propranolol. Myocardial ischaemia was defined as ST-segment depression of > or = 1 mm (60 msec past the J-point) persisting for > or = one minute. For the entire anaesthetic course (induction to post-emergence), there was no difference between groups for either duration or magnitude outside the < 80 or > 120% range for HR or MAP. However, when the period of emergence from anaesthesia (reversal of neuromuscular blockade to post-extubation) was assessed, more patients were hypertensive (P = 0.004) and required vasodilator therapy in Group Iso (10/13 vs 5/14; P = 0.038 Fisher's Exact Test). The mean dose of labetalol was greater in Group Iso (P = 0.035). No patient demonstrated myocardial ischaemia during ICA cross-clamp. On emergence, 6/13 patients in Group Iso demonstrated myocardial ischaemia compared with 1/14 in Group Prop (P = 0.029). Therefore, supporting the blood pressure with phenylephrine, during the period of ICA cross-clamping, appears to be safe as we did not observe any myocardial ischaemia at this time. During emergence from anaesthesia, haemodynamic instability was associated with myocardial ischaemia. Under these specific experimental conditions, with emergence, hypertension and myocardial ischaemia were more prevalent with more frequent pharmacological interventions in patients receiving isoflurane.

Aged↗

Coronary artery disease in patients with type A aortic dissection.

The usefulness of preoperative coronary arteriography in patients with type A dissection of the aorta is controversial. To determine the prevalence of arteriosclerotic coronary artery disease in patients with type A dissection of the aorta, we reviewed our experience in 62 patients (42 with acute dissection and 20 with chronic dissection) who underwent operation between January 1, 1986, and December 31, 1993. Among 23 patients with acute dissection who underwent coronary arteriography, 8 (34.8%) had one or more coronary artery lesions causing a greater than 50% narrowing. Among 14 patients with chronic dissection who underwent coronary arteriography, 6 (42.9%) had one or more coronary artery lesions causing a greater than 50% narrowing. There were no fatal complications associated with coronary arteriography. Four patients with acute dissection and 6 patients with chronic dissection underwent coronary artery bypass grafting at the time of operative repair of the aortic dissection, with no operative deaths. On the basis of these findings and the success of combined coronary artery bypass grafting and aortic repair, we recommend that patients with an acute type A dissection who are in stable condition and all patients with a chronic type A dissection of the aorta should undergo preoperative coronary arteriography.

Acute Disease↗

Revascularization after acute myocardial infarction.

BACKGROUND: The optimal timing for coronary artery bypass grafting (CABG) after acute myocardial infarction (MI) remains controversial. METHODS: We examined our experience retrospectively in 3,942 patients who underwent CABG between 1986 and 1993, including 2,296 patients after acute MI. RESULTS: The operative mortality associated with increasing time intervals between MI and CABG were 9.1%, 8.3%, 5.2%, 6.5%, and 2.9%, for less than 6 hours, 6 hours to 2 days, 2 to 14 days, 2 to 6 weeks, and more than 6 weeks, respectively. In comparison, the operative mortality was 2.5% for patients with no history of acute MI. The incidence of permanent stroke and perioperative MI were greater and the length of postoperative hospitalization was longer for patients undergoing CABG early after MI. For patients undergoing operation electively, however, the operative mortality associated with increasing time intervals between MI and CABG were less, at 0.0%, 3.6%, 2.1%, 6.4%, and 2.1% for less than 6 hours, 6 hours to 2 days, 2 to 14 days, 2 to 6 weeks, and more than 6 weeks, respectively. For patients undergoing CABG within 14 days of MI, the operative mortality was 5.3% for those receiving an intraaortic balloon pump preoperatively for postinfarction angina, but 11.8% for those who underwent urgent/emergent operation without intraaortic balloon pump support. CONCLUSIONS: Elective CABG can be accomplished with acceptable morbidity and mortality early after acute MI if an elective operation is possible. In addition, the intraaortic balloon pump should be used aggressively in patients with postinfarction angina to allow for elective rather than urgent/emergent operation.

Adult↗

Cerebral amyloid angiopathy presenting as a brain mass.

The MR images of a patient with cerebral amyloid angiopathy (a localized vascular deposition of amyloid without evidence of systemic amyloidosis) showed an extensive right temporoparietal lobe mass with frontal lobe extension that was slightly hypointense on T1-weighted images and heterogeneously hyperintense on T2-weighted images. No contrast enhancement was identified on MR imaging.

Brain Neoplasms↗

Biopsy-induced tricuspid regurgitation after cardiac transplantation.

Transvenous endomyocardial biopsy is now well-established as the gold standard for evaluation of possible rejection episodes after cardiac transplantation. From 1985 to August 1992, 1990 patients have undergone 193 cardiac transplantations at Barnes Hospital. One hundred eighty-three patients survived their initial hospitalization and serve as the study group. Their records were reviewed for the purposes of identifying those with tricuspid regurgitation as a complication of right ventricular endomyocardial biopsy. These patients have undergone a total of 2,960 biopsies for an average of 16.2 biopsies per patient. Over a mean follow-up period of 4.22 years, all patients have been evaluated with standard two-dimensional echocardiograms. Mild to moderate tricuspid regurgitation was very common, but was thought to be biopsy-induced only if severe and accompanied by flail components of the tricuspid valve. Twelve patients were identified with this entity at our institution. Of these, 5 had no symptoms and were receiving no diuretics, 3 had mild symptoms consisting of lower extremity edema and continued to receive diuretics, 2 had moderate symptoms, and 2 had right heart failure and anasarca refractory to medical therapy. Both of the severely affected patients subsequently required tricuspid valve replacement. We conclude that the tricuspid valve apparatus is at significant risk of injury during endomyocardial biopsy, that most patients will be minimally symptomatic due to tricuspid regurgitation when this injury occurs, and that when the injury is accompanied by severe symptoms, the likelihood of improvement with medical therapy is small.

Actuarial Analysis↗

Potential ablation of accessory atrioventricular pathways: injection of alcohol into the atrioventricular groove.

Accessory atrioventricular (AV) pathways responsible for the Wolff-Parkinson-White syndrome have been treated successfully by surgical and radiofrequency catheter ablation techniques. In this study, we explored the feasibility of permanent chemical ablation of accessory pathways by direct injection of 100% ethanol into the canine AV groove. Right coronary artery blood flow and AV compartment pressure were measured in 5 adult mongrel dogs (part I) during injection of saline solution (10 to 15 mL) into the right AV groove. Atrioventricular groove compartment pressure increased from 1 +/- 1 to 31 +/- 12 mm Hg (p < 0.0001) and right coronary artery blood flow increased slightly from 117 +/- 17 to 138 +/- 44 mL/min (p = not significant). In 8 additional dogs (part II), 100% ethanol (10 mL) was injected into the left AV groove. After 6 weeks (n = 6) or 12 weeks (n = 2), histologic examination of the left AV groove demonstrated localized fibrous replacement of injured epicardial muscle, with only scant inflammatory infiltrate. Mild intimal fibrosis and intimal proliferation were present in the circumflex artery and its larger branches, but no significant luminal narrowing was evident. Angiograms at 12 weeks (n = 2) demonstrated no significant narrowing of the circumflex artery. In summary, injection of 100% ethanol into the AV groove is capable of locally ablating myocardial tissue, presumably including conductive tissues, while sparing the coronary arteries.

Animals↗

Comparison of cardiac output measurement by continuous thermodilution with electromagnetometry in adult cardiac surgical patients.

A pulmonary artery catheter (PAC) capable of continuous cardiac output (CCO) determination by thermodilution has recently been introduced. The purpose of this study was to compare CCO with two other methods of cardiac output (Ot) determination: electromagnetometry (EM) and standard bolus thermodilution cardiac output (BCO). Following median sternotomy and pericardiotomy, an EM ring probe was placed around the ascending aorta in 25 adult cardiac surgical patients and connected to an EM flowmeter interfaced with a calibrated strip recorder. Measurements were obtained over a 15- to 20-minute interval during a period of stable EM-determined Ot prior to initiation of cardiopulmonary bypass and in the absence of surgical stimulation. The CCO system averages Ot over a 3-minute interval, updating the measurement every 30 seconds. Cardiac output determined by the CCO system was compared with EM Ot averaged from the prior 3-minute period and with BCO obtained immediately after changing the Ot monitor from the continuous to bolus mode. Compared with EM, the bias for CCO was -0.48 L/min, precision 0.56 L/min, and the limits of agreement 1.12 L/min. Bias, precision, and limits of agreement of CCO compared with BCO were 0.41, 0.82, 1.64 L/min, respectively. Correlation between EM and CCO was r = 0.80 and between CCO and BCO r = 0.64. Cardiac output determined by CCO was within 10% of the EM determination for 37 measurements, between 10% and 20% for 17, and greater than 20% for 7 measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Hazards of postoperative atrial arrhythmias.

Between January 1, 1986, and December 31, 1991, 4,507 adult patients underwent cardiac surgical procedures requiring cardiopulmonary bypass. Of these patients, 3,983 patients who did not undergo operation for supraventricular tachycardia and who were in normal sinus rhythm preoperatively form the study group for the present study. Postoperatively, all patients were monitored continuously for the development of arrhythmias until the time of hospital discharge. The incidence of atrial arrhythmias requiring treatment for the most commonly performed operative procedures were as follows: coronary artery bypass grafting, 31.9%; coronary artery bypass grafting and mitral valve replacement, 63.6%; coronary artery bypass grafting and aortic valve replacement, 48.8%; and heart transplantation, 11.1%. For all patients considered collectively, the risk factors associated with an increased incidence of postoperative atrial arrhythmias (p < 0.05 by multivariate logistic regression) included increasing patient age, preoperative use of digoxin, history of rheumatic heart disease, chronic obstructive pulmonary disease, and increasing aortic cross-clamp time. Postoperative atrial fibrillation was associated with an increased incidence of postoperative stroke (3.3% versus 1.4%; p < 0.0005), increased length of hospitalization in the intensive care unit (5.7 versus 3.4 days; p = 0.001) and postoperative nursing ward (10.9 versus 7.5 days; p = 0.0001), increased incidence of postoperative ventricular tachycardia or fibrillation (9.2% versus 4.0%; p < 0.0005), and an increased need for placement of a permanent pacemaker (3.7% versus 1.6%; p < 0.0005). These data provide a basis for targeting specific patient subgroups for prospective, randomized trials of therapeutic modalities designed to decrease the incidence of postoperative atrial arrhythmias.

Atrial Fibrillation↗

Myocardial contractile state in dogs with chronic mitral regurgitation: echocardiographic approach to the peak systolic pressure/end-systolic area relationship.

Analysis of the pressure-dimension relationship provides a sensitive index of myocardial contractility, but widespread application of this method is limited because it requires invasive measurement techniques. The recent development of two-dimensional echocardiographic automatic boundary detection permits accurate and reproducible on-line measurement of ventricular cavity areas that can be combined with ventricular pressure measurements to derive instantaneous pressure-area relationships. In anesthetized closed-chest dogs with chronic mitral regurgitation, the slope of the ventricular pressure-area relationship was determined by obtaining baseline measurements (at baseline and after infusion of methoxamine or nitroglycerin) and measurements after infusion of a positive inotropic drug (dobutamine) alone and concurrently with methoxamine or nitroglycerin. The slope of the ventricular pressure-area relationship was altered significantly (p = 0.0002) and in the expected direction (steeper slope) from baseline to the enhanced myocardial inotropic state after dobutamine infusion. Thus on-line echocardiographic measurements of ventricular cavity area facilitate the implementation of elastance determinations to serially evaluate the myocardial contractile state under conditions of alterations in preload, afterload, and the inotropic state. This method is promising for the noninvasive evaluation of left ventricular function modified by diverse pathologic conditions.

Animals↗

Inaccuracy of cardiac output by thermodilution during acute tricuspid regurgitation.

We have been comparing cardiac output measured with a novel Doppler pulmonary artery catheter to that measured by thermodilution and aortic electromagnetometry in cardiac surgical patients. We report here our observation of a nearly twofold increase in thermodilution cardiac output after the acute intraoperative onset of tricuspid regurgitation that was not confirmed by the novel catheter or direct measurement of aortic blood flow. We conclude that in some patients, acute tricuspid regurgitation may lessen the reliability of thermodilution cardiac output.

Acute Disease↗

Comparison of cardiac output measured by intrapulmonary artery Doppler, thermodilution, and electromagnetometry.

A Doppler pulmonary artery catheter system (Doppler cardiac output monitor or DOPCOM) that continuously measures instantaneous and mean cardiac output was recently introduced. Because thermodilution (TD) flow measurements may not represent an adequate standard, the present study was designed to compare TD and DOPCOM cardiac output measurements with aortic electromagnetic (EM) flow in cardiac surgical patients. Twenty-one patients scheduled for elective coronary artery bypass grafting were enrolled in the study. Simultaneous measurement of cardiac output by all three methods was performed before cardiopulmonary bypass, after cardiopulmonary bypass with the aorta cannulated and volume intermittently infused, and after decannulation. Analysis of all data demonstrated fair TD and EM correlation (r = 0.80), with minimal bias (0.03 +/- 1.21 L/min) and a median absolute error of 0.53 L/min; DOPCOM and EM data showed moderate correlation (r = 0.64), a bias of -0.61 +/- 1.50 L/min, and a median absolute error the same as TD (0.51 L/min). However, distribution of DOPCOM values was heavily skewed by 3 patients in whom flow measurements immediately after cardiopulmonary bypass were markedly different between the DOPCOM and electromagnetometry, probably because of malposition of the Doppler transducers secondary to partial catheter withdrawal during bypass. Consistent with this theory was the finding that before CPB, the DOPCOM was significantly better than TD in predicting EM flow (median absolute error: DOPCOM, 0.12 L/min, and TD, 0.48 L/min; p = 0.04). Our data suggest that, in general, the DOPCOM shows similar precision to TD for predicting EM flow measurements, although the DOPCOM may underestimate actual flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Intraaortic balloon counterpulsation: patterns of usage and outcome in cardiac surgery patients.

Between January 1, 1986, and May 6, 1991, 7,884 cardiac surgical procedures requiring cardiopulmonary bypass were performed at our institution, including 672 (9.8% of adult procedures) performed in 669 patients that were associated with preoperative (n = 240), intraoperative (n = 353), or postoperative (n = 79) use of an intraaortic balloon pump. The mean age of recipients was 65.3 years (range, 16 to 89 years). Intraaortic balloon pump usage increased during the study period from 6.4% of patients (83/1,298) in 1986 to 12.7% of patients (169/1,333) in 1990. The relative distribution between preoperative (mean, 35.7%), intraoperative (52.5%), and postoperative (11.8%) insertion remained nearly constant during the study period. The overall operative (30-day) mortality for patients with preoperative, intraoperative, or postoperative insertion of the intraaortic balloon pump was 19.6%, 32.3%, and 40.5%, respectively (X2 = 16.4; p less than 0.001). Although use of the intraaortic balloon pump in the intraoperative and postoperative settings is accompanied by a favorable outcome in most patients, the high associated mortality suggests the need for earlier use of the intraaortic balloon pump or other supportive measures such as the ventricular assist device.

Angina, Unstable↗

Drug interactions with sufentanil. Hemodynamic effects of premedication and muscle relaxants.

Induction of anesthesia with synthetic opioids is occasionally accompanied by undesirable hemodynamic changes such as tachycardia and hypertension, or bradycardia and hypotension. We hypothesized that drug interactions cause many of these adverse responses. Therefore, we conducted a randomized double-blind study to investigate the interactive effect of premedication and muscle relaxants on the hemodynamic response to induction with intravenous (iv) sufentanil 10 micrograms.kg-1. Eighty patients with left ventricular ejection fraction greater than or equal to 0.40, undergoing elective coronary artery surgery, were premedicated with either morphine 0.1 mg.kg-1 and scopolamine 6 micrograms.kg-1 intramuscularly, or lorazepam 60 micrograms.kg-1 orally, and paralyzed with either pancuronium 0.1 mg.kg-1 or vecuronium 0.1 mg.kg-1 iv. The four treatment groups were SP (morphine-scopolamine + pancuronium), LP (lorazepam + pancuronium), SV (morphine-scopolamine + vecuronium), and LV (lorazepam + vecuronium). Hemodynamics were recorded at three time periods: 1) control, 2) induction, and 3) intubation. Premedication-relaxant interactions significantly affected hemodynamics. In group SP, mean heart rate (HR) increased significantly on induction (56 +/- 11 to 69 +/- 13 beats.min-1), while mean arterial pressure (MAP) and cardiac index (CI) were unchanged. HR, MAP, and CI were significantly higher after induction in group SP compared to the other three groups. In group LP, mean HR increased less than in group SP (56 +/- 8 to 62 +/- 14 beats.min-1), whereas MAP and CI declined significantly. In group SV, HR and CI were unchanged, but MAP declined significantly. In group LV, HR was stable, whereas both MAP and CI declined significantly. The incidence of pharmacologic interventions during the study period also differed significantly among groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Treatment of proximal aortic hypertension after thoracic aortic cross-clamping in dogs. Phlebotomy versus sodium nitroprusside/isoflurane.

Thoracic aortic cross-clamping causes proximal aortic hypertension. Theoretically, the method used to treat hypertension can influence spinal cord perfusion pressure and neurologic outcome. Phlebotomy was compared to sodium nitroprusside/isoflurane in terms of ability to treat increased proximal mean aortic pressure (MAPp) after thoracic aortic cross-clamping in dogs. Dogs were assigned randomly to one of three groups depending on the method used to treat hypertension after cross clamping: 1) phlebotomy (n = 10); 2) sodium nitroprusside/isoflurane (n = 11); and 3) control (no treatment) (n = 8). In each dog, anesthesia was maintained with isoflurane in oxygen, 1.4% end-tidal. The thoracic aorta was occluded 2.5 cm distal to the left subclavian artery for 50 min and then was released. Hemodynamics, cerebrospinal fluid pressure (CSFP), and regional blood flows by the radioactive microsphere technique, were measured at 1) baseline; 2) 2 min after aortic cross-clamping; 3) after treatment of proximal aortic hypertension; 4) 5 min after aortic unclamping; and 5) 30 min after resuscitation. At 24 h, a neurologic assessment was performed. Thoracic aortic cross-clamping increased MAPp, decreased distal MAP (MAPd), and reduced lumbar spinal cord perfusion pressure (SCPPl), [SCPPl = MAPd - CSFP], in all three groups. Control of increased MAPp necessitated removal of 36 +/- 9 ml/kg of blood in the phlebotomy group. In the sodium nitroprusside/isoflurane group, sodium nitroprusside (16 micrograms.kg-1.min-1) was infused and end-tidal isoflurane concentration increased to 2.5 +/- 0.7%, restoring MAPp to baseline level.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Transesophageal echocardiography predicts successful withdrawal of ventricular assist devices.

Transesophageal echocardiography has been found to be an effective technique for the real-time assessment of myocardial and valvular function in postoperative patients. To determine the value of transesophageal echocardiography in patients with mechanical assist devices, we performed daily, bedside transesophageal echocardiography on 16 patients with right (n = 3), left (n = 1), or biventricular assist devices (n = 12). We obtained four-chamber and short-axis views in all patients. Valvular function and the presence of left-to-right shunts were evaluated by means of color flow Doppler imaging. During the echocardiographic study ventricular assist device flow was diminished to less than 1.5 L/min, and inotropic agents (dobutamine or epinephrine) were given to assess ventricular reserve. Changes in day-to-day ventricular function were assessed in comparisons made by two observers (one unaware of the study sequence) using a semiquantitative method for wall motion analysis. The left ventricular wall motion scores in the patients successfully weaned from left or biventricular assist devices (n = 5) improved (14.2 +/- 1.6 versus 8.2 +/- 1.5, p < 0.0001). The scores did not improve in patients who remained dependent on the devices (n = 8). Two patients with only right ventricular assist devices were successfully weaned after documentation of improvement of right ventricular function by transesophageal echocardiography. Transesophageal echocardiography documented a clot compressing the heart in three patients; intracavitary thrombi were seen in two other patients. Marked hemodynamic improvement occurred after surgical decompression. In conclusion, transesophageal echocardiography is a safe, effective method for the assessment of ventricular function of patients on ventricular assist device support. In addition, it allows one to assess valvular function and the presence or absence of impaired ventricular filling.

Adult↗

Adequacy of preparation for barium enema among elderly outpatients.

OBJECTIVE: To determine whether outpatients 75 years of age or older have a higher rate of inadequate bowel preparation for barium enema and of complications associated with the preparation and the test than patients aged 55 to 74 years. DESIGN: Cross-sectional survey. SETTING: Radiology department in a teaching hospital. PATIENTS: Patients 55 years or older referred for a barium enema from March to August 1988. OUTCOME MEASURES: All films were reviewed independently by a study radiologist blind to the staff radiologist's report. Patients were interviewed by telephone within several days after the test to assess the occurrence of problems during the preparation or the test. MAIN RESULTS: Of the 213 patients assessed 72 were excluded: 43 refused to participate or could not be contacted, 16 had previously undergone colonic surgery, and 13 were excluded for other reasons. The remaining 141 patients were separated into three age groups: those 55 to 64 years (46 patients), those 65 to 74 (47) and those 75 or older (48). In 104 cases (74%) the bowel had been prepared adequately; there was no significant difference between the three groups with regard to the adequacy of preparation. The incidence of problems reported by the patients did not differ significantly between the groups. CONCLUSIONS: Outpatients aged 75 years or more are no more likely than those aged 55 to 74 to have problems with bowel preparation or the barium enema itself. Age should not be a criterion for exclusion from barium enema. To try to lower the rate of poor bowel preparation clinicians and radiologists should consider counselling patients more carefully about the importance of proper preparation. Also, the current method of preparation could be examined to determine whether simple changes would significantly improve colon cleanliness.

Aged↗

The prevalence of gallstone disease in very old institutionalized persons.

We present the results of a study that was undertaken at a large geriatric nursing home to assess the prevalence of gallstone disease in very old institutionalized persons. One hundred seventeen residents underwent ultrasound examination of the gallbladder. Two thirds of 82 women and half of 35 men had gallstone disease. When stratified for age, 80% of women and men over the age of 90 years were positive for the disease. In summary, the prevalence of gallstone disease in our very old nursing home population was found to be unexpectedly high.

Aged↗

Effect of acylation stimulating protein on the triacylglycerol synthetic pathway of human adipose tissue.

Acylation stimulating protein (ASP) is a 14 kDa plasma protein which causes in vitro triacylglycerol synthesis in human adipocytes and fibroblasts to increase substantially. ASP was found to stimulate human adipose tissue microsomal glycerophosphate acyltransferase and diacylglycerol acyltransferase activities by 23% and 90%, respectively. However, phosphatidate phosphohydrolase activity showed no increase in activity, nor did microsomal acyl-CoA synthetase activity. Moreover, ASP did not decrease the apparent Km of diacylglycerol acyltransferase (DGAT), but rather increased its apparent Vmax suggesting direct interaction of ASP with DGAT.

Acyltransferases↗