PubMed Health⌕ Search

Biomedical subjects

M Rosenbloom

Publications and source records attributed to M Rosenbloom.

At least 55 records · Page 3Linked to original sources
PubMed1991

Alfentanil pharmacokinetics in patients undergoing abdominal aortic surgery.

The pharmacokinetics of alfentanil, 300 micrograms.kg-1 IV, were determined in patients undergoing elective abdominal aortic reconstruction. The mean age (+/- SD) of the patients was 64.3 +/- 7.4 yr; their mean weight was 74.7 +/- 13.8 kg. Five patients underwent aneurysm repair and six had aortobifemoral grafting. Serum alfentanil concentrations were measured by gas-liquid chromatography in samples drawn at increasing intervals over a 24-hr period. A three-compartment model was fitted to the concentration versus time data. The volume of the central compartment and the volume of distribution at steady state (Vdss) were 0.44 +/- 0.022 and 0.63 +/- 0.32 L.kg-1, respectively. Total drug clearance was 6.4 = 1.9 ml.min-1.kg-1. The elimination half-time was 3.7 +/- 2.6 hr. Patient age was positively correlated with both Vdss and elimination half-time. There were no significant correlations between the pharmacokinetic variables and the duration of aortic cross-clamping, the duration of surgery, or the rate or total volume of IV fluids infused intraoperatively. In general surgical patients, the elimination half-time of alfentanil has been reported to be 1.2-2.0 hr. Although the elimination half-time of alfentanil was longer in patients undergoing abdominal aortic surgery, alfentanil was eliminated much faster than either fentanyl or sufentanil in this patient population.

Age Factors↗
PubMed1991

Left ventricular outflow obstruction resulting from insertion of mitral prostheses leaving the native leaflets intact: adverse clinical outcome in seven patients.

Left ventricular (LV) outflow obstruction may result from retaining the anterior mitral leaflet when a mitral prosthesis is inserted in the mitral anulus. We retrospectively reviewed the echocardiograms (two-dimensional Doppler and Doppler color flow imaging, or transesophageal with color flow imaging) obtained in seven patients with preoperative mitral regurgitation who had a prosthesis implanted with the native mitral leaflets left intact. Systolic anterior motion of the native anterior mitral leaflet, as seen in dynamic LV outflow tract obstruction, was observed in six of seven patients. LV fractional shortening preoperatively was less than or equal to 0.25 in all (mean 0.20 +/- 0.04) and did not significantly (p = ns) increase postoperatively (mean 0.27 +/- 0.12). Color flow imaging revealed disturbed systolic flow in the LV outflow tract in five patients, and all had systolic anterior motion of the native anterior mitral leaflet. Continuous wave Doppler detected significant systolic LV outflow tract jets in five patients averaging 4.1 +/- 0.9 m/sec. Mitral prosthetic function was normal (pressure half-time of 81 +/- 25 msec and mean gradient of 7 +/- 3 mm Hg +/- SD) in five patients. Clinical follow-up revealed that all had died, six of them within 2 months of their operation. Thus systolic anterior motion of the native anterior mitral leaflet occurs commonly after prosthetic mitral valve insertion with the native leaflets left intact. Continuous wave Doppler often demonstrates increased systolic LV outflow tract velocities consistent with dynamic LV outflow obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Simplified method for femoral venous cannulation.

A simple method for rapidly achieving femoral venous cannulation is described. We have found this method to be particularly useful for femoral cannulation when the patient is in the thoracotomy position.

Catheterization, Peripheral↗
PubMed1991

Phlebotomy reverses the hemodynamic consequences of thoracic aortic cross-clamping: relationships between central venous pressure and cerebrospinal fluid pressure.

In dogs (n = 11) anesthetized with sodium pentobarbital (to an isoelectric EEG), the authors investigated the influence of thoracic aortic cross-clamping (AXC) on systemic hemodynamics and cerebrospinal fluid pressure (CSFP) with concurrent measurement of total brain flow (tCBF) and regional (cervical, thoracic, and lumbar) spinal cord blood flow (SCBF). The effect of phlebotomy (to control the hemodynamic consequences of AXC) on tCBF and SCBF was assessed. Radioactive microspheres were injected at four time periods in each animal: 1) at baseline; 2) with application of the AXC; 3) after phlebotomy, to reduce the proximal mean arterial pressure (MAPp) to baseline values; and 4) 2 min after removal of the AXC (mean AXC time 68 +/- 6 min). With application of the AXC, the MAPp, central venous pressure (CVP), and CSFP significantly increased (104 +/- 6 to 156 +/- 6 mmHg, 3.4 +/- 0.4 to 5.2 +/- 0.7 mmHg, and 3.3 +/- 0.7 to 5.2 +/- 0.8 mmHg, respectively), while distal mean aortic pressure (MAPd) significantly decreased (98 +/- 6 to 14 +/- 1 1 mmHg). Phlebotomy (24 +/- 3 ml.kg-1) significantly decreased MAPp (to 106 +/- 6 mmHg), CVP (to 1.6 +/- 0.6 mmHg), and CSFP (to 1.2 +/- 1.1 mmHg). The CSFP changed in parallel with the changes in CVP, a result suggesting that the alterations in CSFP depended on cardiac preload. The spinal cord perfusion pressure (SCPP; SCPP = MAPd - CSFP) was unchanged after phlebotomy, since both MAPd and CSFP decreased. The tCBF and cervical SCBF were unchanged when MAPp increased by 50% with application of the AXC; this indicated that autoregulation was intact.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

A comparison of desflurane and isoflurane in patients undergoing coronary artery surgery.

Animal studies indicate that desflurane and isoflurane have similar hemodynamic effects when administered in equipotent anesthetic concentrations. The authors compared desflurane and isoflurane, used as primary anesthetics for patients undergoing elective coronary artery bypass surgery whose left ventricular ejection fractions were greater than 0.34. After induction of anesthesia with thiopental (dose 180 +/- 45 mg [mean +/- standard deviation]) and fentanyl, 10 micrograms.kg-1, either desflurane or isoflurane was administered to maintain systolic blood pressure within 70-120% of, and heart rates less than 120% of, the patients' average preoperative values. If adjusting the end-tidal anesthetic concentration within the range of 0-2.0 MAC could not maintain these predefined hemodynamic limits, additional fentanyl or vasoactive drugs were used. Induction and maintenance of anesthesia was accompanied by a significant decrease in mean arterial pressure in both groups (desflurane 97 +/- 12 mmHg at control, decreasing to 71 +/- 5 mmHg during skin preparation; isoflurane 95 +/- 9 mmHg at control, 74 +/- 9 mmHg during skin preparation). One minute after sternotomy, mean arterial pressure in the isoflurane group had returned to control, 97 +/- 9 mmHg, which was significantly greater than in the desflurane group, 87 +/- 12 mmHg. Systolic arterial pressure was also significantly greater in the isoflurane group 1 min after intubation, during skin preparation, and 1 min after sternotomy. Otherwise, the hemodynamic effects of these volatile agents were similar. There were no differences between groups in the incidence of ECG changes indicative of myocardial ischemia prior to cardiopulmonary bypass, perioperative myocardial infarction, or perioperative mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Brain magnetic resonance imaging: approaches for investigating schizophrenia.

Magnetic resonance imaging (MRI) offers the potential for identifying, in vivo, specific brain abnormalities associated with schizophrenia. The detection of small morphological differences in areas such as the prefrontal cortex, limbic structures, and basal ganglia requires attention to a number of technical and methodological details. The effects of age, height, sex, head size, and overall tissue loss are of particular concern and are discussed. MRI acquisition and processing techniques for improving gray/white tissue contrast and image resolution are described, as are techniques for quantitative, volumetric measurement of localized regions of interest and specific brain structures as well as of the brain as a whole. Techniques for evaluating frontal lobes, temporal lobes, and basal ganglia integrity are reviewed, and recent observations on these brain regions in patients with schizophrenia are described.

Basal Ganglia↗
PubMed1989

Noninvasive detection of cardiac allograft rejection by analysis of the unipolar peak-to-peak amplitude of intramyocardial electrograms.

The use of standard electrocardiographic monitoring to detect cardiac allograft rejection has become unreliable since the advent of cyclosporine immunosuppression. Unipolar peak-to-peak amplitude analysis has been shown to be a quantitative measure of ischemic myocardial injury. This study was performed to determine if unipolar peak-to-peak amplitude analysis could accurately detect cardiac allograft rejection as determined by blinded endomyocardial biopsies. Ten adult mongrel dogs underwent heterotopic (n = 7) or orthotopic (n = 3) cardiac transplantation with placement of sutureless screw-in electrodes (Medtronic, Inc, Minneapolis, MN) on the anterior and posterior aspect of each ventricle. Postoperatively, animals were immunosuppressed for seven to ten days with cyclosporine and prednisone and then allowed to reject the transplant. Digitally processed intramyocardial electrograms were obtained daily. Endomyocardial biopsy was performed 1 week postoperatively and then at three to five day intervals for histological correlation. A unipolar peak-to-peak amplitude decline of 15% or greater occurred one to three days before the biopsy detection in 10 of 10 episodes of rejection. There were no false negatives and one false positive (although a small focal lymphocytic infiltrate was present). Thus, noninvasive unipolar peak-to-peak amplitude analysis was 100% sensitive and 90% specific in predicting and detecting cardiac allograft rejection.

Animals↗
PubMed1989

Posterolateral exposure for renal artery reconstruction.

Anterior approaches to the renal arteries are complicated by the intervening renal veins, inferior vena cava, and abdominal viscera. We describe techniques of direct posterolateral access to both right and left renal arteries by use of an extended retroperitoneal exposure. This approach allows for grafting from the aorta or iliac artery on either side and is particularly suitable on the left side for direct retropancreatic splenorenal artery anastomosis, which is described in detail. It is also useful for distal reconstruction of branch renal arteries, renal artery embolectomy, and autotransplantation "bench surgery." We have used this approach in 28 patients with no operative deaths and two reconstructive occlusions.

Humans↗
PubMed1989

Operative angiography by intraarterial digital subtraction angiography: a new technique for quality control of carotid endarterectomy.

Fifty patients who had carotid bifurcation endarterectomy as their sole surgical procedure underwent intraoperative completion angiography by means of portable intraarterial digital subtraction angiography. All had subsequent intravenous digital subtraction angiography or duplex scanning during early follow-up. After the endarterectomy site was closed and before the wound was closed, 6 to 8 ml of contrast was injected through a 21-gauge needle while fluoroscopy was performed with a conventional C-arm. The C-arm was coupled to a Quantel IDIS Mobile Digital Subtraction Angiogram Unit (Quantel Medical Products Group, Clemmons, N.C.) for image enhancement and immediate playback. There were no postoperative deaths or neurologic complications. Abnormal radiographic results led to reopening of endarterectomy sites in eight patients, which resulted in successful correction of the defects. There was a single asymptomatic occlusion of the internal carotid artery at 3 weeks in the patient with the only false-negative result on the completion study. Intraarterial digital subtraction angiography is a safe and useful technique for intraoperative quality control of carotid endarterectomy. It provides visual images that can be easily repeated in several projections, uses small volumes of contrast, and has no timing requirements for filming and injecting.

Carotid Artery Diseases↗
PubMed1989

Pharmacokinetics of sufentanil in patients undergoing abdominal aortic surgery.

The authors determined the pharmacokinetics of sufentanil, 12.5 micrograms.kg-1 iv in patients undergoing elective abdominal aortic surgery. The mean age (+/- SD) of the ten patients was 68.4 +/- 7.9 yr; their mean weight was 74.4 +/- 19.1 kg. Six patients underwent aortobifemoral grafting and four had abdominal aortic aneurysm repair. Serum sufentanil concentrations were determined in samples drawn at increasing intervals over a 24-h period. A three-compartment pharmacokinetic model was fit to the concentration versus time data. Total drug clearance was 15.0 +/- 3.2 ml.min-1.kg-1. The volume of distribution at steady-state (Vdss) was 8.7 +/- 4.5 l.kg-1. The elimination half-time were positively correlated with patient age. There were no significant correlations between the pharmacokinetic variables and the duration of aortic cross-clamping, the duration of surgery, or the rate or total volume of iv fluids given intraoperatively. In general surgical patients, the mean elimination half-time of sufentanil has been reported to be 2.7 h. When sufentanil is used in large doses as the primary anesthetic agent for patients undergoing abdominal aortic surgery, the long elimination half-time observed implies that recovery will take much longer than would have been anticipated from previously published pharmacokinetic data.

Aged↗
PubMed1988

Catecholamine responses to anesthetic induction with fentanyl and sufentanil.

In a randomized study, the authors examined the changes in plasma epinephrine and norepinephrine concentrations associated with induction of anesthesia and surgery in 33 patients with good ventricular function undergoing elective coronary artery surgery. After premedication with morphine and scopolamine, patients received either fentanyl, 100 micrograms/kg (n = 16), or sufentanil, 15 micrograms/kg, (n = 17), intravenously (IV), over 10 minutes to induce anesthesia. Metocurine, 0.42 mg/kg, IV, produced muscle relaxation. Arterial blood for plasma catecholamine determinations was drawn prior to induction, every two minutes throughout induction, one minute following endotracheal intubation, and one minute after sternotomy. Plasma epinephrine concentration was unchanged with either induction agent. Plasma norepinephrine concentration increased significantly after administration of either narcotic, peaked between six and ten minutes into induction, and returned to the preinduction value after intubation. Induction-related changes in arterial pressure and pulmonary capillary wedge pressure were significantly correlated with changes in the logarithm of plasma norepinephrine concentration. Similar degrees of endogenous norepinephrine release appear to accompany induction with equipotent doses of fentanyl and sufentanil in patients premedicated with morphine and scopolamine. Norepinephrine release may influence the hemodynamic response to induction with narcotics.

Anesthesia, Intravenous↗
PubMed1988

Noninvasive three-dimensional reconstruction of the heart and great vessels by ECG-gated magnetic resonance imaging: a new diagnostic modality.

We have developed a new method of computer image processing that allows true three-dimensional (3-D) images of the heart and great vessels to be reconstructed from standard ECG-gated two-dimensional magnetic resonance (MR) images. Contiguous 5-mm thick MR images of the thorax from the level of the cardiac apex to the aortic arch were obtained in 4 normal volunteers and 3 patients with congenital heart disease: 1 with pseudotruncus arteriosus and 1 with a ventricular septal defect, each with Eisenmenger's complex, and 1 with aortic coarctation. Each image could be obtained at up to seven different intervals throughout the cardiac cycle with ECG gating. The scanning procedure is noninvasive and requires no contrast material. Using standard software, images from each interval in the cardiac cycle were edited to isolate pertinent cardiac and great vessel structures. High-resolution 3-D reconstructions were formed for each interval by stacking the edited images. Sequential projection of 3-D reconstructions from each interval yields four-dimensional (includes time) cine views. Both 3-D and cine views can be obtained from any axis or divided in any plane to allow accurate, noninvasive assessment of cardiac and great vessel anatomy, chamber volumes, and regional and global wall motion. Noninvasive 3-D reconstruction of the heart and great vessels provides accurate anatomical data not available from standard cardiac catheterization or other noninvasive diagnostic procedures, and aids in the preoperative planning of the procedure to correct complex congenital malformations.

Adult↗
PubMed1988

Premedication and high-dose fentanyl anesthesia for myocardial revascularization: a comparison of lorazepam versus morphine-scopolamine.

Using a randomized double-blind placebo-controlled experimental protocol, the authors compared two premedication regimens in 42 patients undergoing elective myocardial revascularization. Group L patients (n = 23) received lorazepam 0.06 mg/kg po 90 min preoperatively, while group M patients (n = 19) received morphine 0.1 mg/kg im, plus scopolamine 0.006 mg/kg im 60 min preoperatively. Anesthesia was induced with fentanyl 100 micrograms/kg and atracurium 0.50 mg/kg administered over 10 min. The treatment groups did not differ significantly with respect to the degree of sedation or anxiolysis achieved, or the rapidity of induction with fentanyl. Premedication significantly influenced the hemodynamic response to anesthetic induction. Hemodynamics were stable post-induction in group M, but cardiovascular depression was noted in group L. Control heart rate (HR) was lower in group L. The HR, arterial pressure, and cardiac index were significantly lower, following both induction and intubation, in group L. Following sternotomy hemodynamics were identical in both groups. Serum fentanyl concentration was significantly higher during intubation in group L, probably secondary to the pharmacokinetic consequences of a decreased CI. New electrocardiographic evidence of myocardial ischemia did not occur in either group. Based on their findings with fentanyl-at-racurium, and their review of the literature, the authors speculate that premedication exerts a significant hemodynamic effect during induction with other narcotic-relaxant combinations.

Anesthesia, Intravenous↗
PubMed1988

Noninvasive assessment of treatment of cardiac allograft rejection with indium-111-labeled lymphocytes.

We have shown previously that cardiac allograft rejection can be detected noninvasively with gamma scintigraphy after administration of indium-111 (111In)-labeled lymphocytes. To determine whether this technique could be used to monitor salvage immunosuppressive therapy in reversing rejection, 5 dogs were studied after thoracic heterotopic cardiac transplantation. Initial postoperative immunosuppression was maintained with cyclosporine (10-20 mg/kg/day) and prednisone (1 mg/kg/day) for 7 days after transplantation and then discontinued. Scintigraphy after administration of labeled lymphocytes was performed during initial immunosuppression and every 3 days after its termination. Endomyocardial biopsies were obtained on each day scintigraphy was performed. Once scintigraphic criteria for rejection were met (111In-lymphocyte uptake greater than mean +/- 2SD of normal myocardium), animals were treated with high dose methylprednisolone and cyclosporine. Myocardial 111In-lymphocyte activity compared with that in blood was 0.7 +/- 0.8 during initial immunosuppression, increased to 5.7 +/- 3.5 after termination of therapy (P less than 0.01), and diminished with salvage immunosuppressive therapy to 0.5 +/- 0.8 (P = NS compared with native hearts or allografts during initial immunosuppression). Scintigraphy accurately predicted all but one episode of biopsy-documented rejection and accurately detected reversal of rejection during salvage. Thus, scintigraphy with 111In-labeled lymphocytes should facilitate noninvasive monitoring of antirejection therapy in patients.

Animals↗
PubMed1988

Brain CT changes in alcoholics: effects of age and alcohol consumption.

A computerized tomographic (CT) brain scan and assessments of lifetime alcohol consumption, body size, and cognitive performance were performed in 37 male alcoholics, aged 26-62 years. Hematocrit and mean corpuscular volume (MCV) were also measured. CT data were analyzed using a semiautomated scoring system yielding measures of percentage of fluid at the ventricles and cortical sulci. Normative brain CT data from 57 community controls spanning the adult age range allowed Z-score assessment of deviation from age norms for each alcoholic. Across the entire group, alcoholics had significantly enlarged ventricles and sulci for their age. Enlargement at both sites correlated significantly with lifetime alcohol consumption. Sulcal enlargement in alcoholics was found across all ages. In contrast, ventricular enlargement was apparent only in older alcoholics and became increasingly exaggerated with age. Measures of body size, hematocrit, and MCV correlated with ventricular but not sulcal enlargement, suggesting that nutritional factors play a role in ventricular enlargement. Associations between neuropsychological performance and CT changes or alcohol consumption were less pronounced and at times counterintuitive. The findings support a modest dose-effect relationship between ethanol exposure and changes in brain morphology, and suggest that ventricles and sulci show a different time course of response. The role of nutritional status needs to be more closely investigated.

Adult↗
PubMed1988

Detection of rejection of canine orthotopic cardiac allografts with indium-111 lymphocytes and gamma scintigraphy.

Previous studies have demonstrated the feasibility of detecting canine heterotopic cardiac allograft rejection scintigraphically after administration of 111In lymphocytes. To determine whether the approach is capable of detecting rejection in orthotopic cardiac transplants in which labeled lymphocytes circulating in the blood pool may reduce sensitivity, the present study was performed in which canine orthotopic cardiac transplants were evaluated in vivo. Immunosuppression was maintained with cyclosporine A (10-20 mg/kg/day) and prednisone (1 mg/kg/day) for 2 wk after transplantation. Subsequently, therapy was tapered. Five successful allografts were evaluated scintigraphically every 3 days after administration of 100-350 microCi 111In autologous lymphocytes. Correction for labeled lymphocytes circulating in the blood pool, but not actively sequestered in the allografts was accomplished by administering 3-6 mCi 99mTc autologous erythrocytes and employing a previously validated blood-pool activity correction technique. Cardiac infiltration of labeled lymphocytes was quantified as percent indium excess (%IE), scintigraphically detectable 111In in the transplant compared with that in blood, and results were compared with those of concomitantly performed endomyocardial biopsy. Scintigraphic %IE for hearts not undergoing rejection manifest histologically was 0.7 +/- 0.4. Percent IE for rejecting hearts was 6.8 +/- 4.0 (p less than 0.05). Scintigraphy detected each episode of rejection detected by biopsy. Scintigraphic criteria for rejection (%IE greater than 2 s.d. above normal) were not manifest in any study in which biopsies did not show rejection. Since scintigraphic results with 111In-labeled lymphocytes were concordant with biopsy results in orthotopic cardiac transplants, noninvasive detection of graft rejection in patients should be attainable with the approach developed.

Animals↗