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Biomedical subjects

R Mohr

Publications and source records attributed to R Mohr.

At least 73 records · Page 4Linked to original sources
PubMed1990

Left ventricular thrombectomy in the early postinfarction period.

Emergency left ventricular thrombectomy was performed on four patients soon after infarction. In three patients surgery was carried out after embolisation had occurred and when a large, residual, protruding, mobile thrombus remained in the left ventricle. Surgery was performed in the fourth patient after a high risk thrombus was detected and initial attempts to lyse it had failed. All four patients had an uneventful recovery and were discharged within two weeks of surgery. These cases indicate that the therapeutic option of left ventricular thrombectomy is feasible for patients with acute infarcts and problematic left ventricular thrombi.

Heart Diseases↗
PubMed1990

Transfusion of fresh whole blood stored (4 degrees C) for short period fails to improve platelet aggregation on extracellular matrix and clinical hemostasis after cardiopulmonary bypass.

It has recently been shown that the hemostatic effect of 1 unit of fresh whole blood is equivalent to the effect of 8 to 10 platelet units. This study was designed to evaluate the effect of short periods of cold (4 degrees C) storage on the hemostatic effect of fresh whole blood transfusion in 36 patients immediately after cardiopulmonary bypass. Twelve patients (group A) received unrefrigerated fresh whole blood, 12 (group B) received fresh whole blood after 5 hours' storage at 4 degrees C, and 12 (group C) after 24 hours' storage at 4 degrees C. For evaluation of platelet function, a method with an extracellular matrix and an electron microscope was used. The platelet function was graded from 1 to 4, with grade 4 being normal aggregation. Postoperatively, group A patients bled less than groups B and C (267 +/- 42 versus 397 +/- 72 and 601 +/- 172 ml/24 hr, respectively, p less than 0.001) and therefore received fewer blood units (1.4 +/- 0.5 versus 2 +/- 0.9 and 3 +/- 1.4, respectively, p less than 0.01). Five patients of group A (42%) reached grade A aggregation after transfusion of unstored fresh whole blood, compared with two (17%) of group B and none (0%) of group C (p less than 0.01). Posttransfusion platelet count and mean platelet volume were not significantly different in the three groups. We conclude that storage at 4 degrees C, even for a short period of 5 hours, diminishes the hemostatic effect of fresh whole blood by decreasing platelet aggregability.

Blood Physiological Phenomena↗
PubMed1990

Is transfusion of fresh plasma after cardiac operations indicated?

Patients undergoing cardiac operations constitute the majority of recipients of fresh frozen plasma. In most centers the reason for transfusing fresh frozen plasma is to replace clotting factors. However, the decrease of clotting factors during cardiopulmonary bypass is not sufficient in most patients to cause abnormal bleeding. One of the major causes of nonsurgical bleeding after cardiac operations is acquired platelet dysfunction, which can be corrected by transfusion of 1 unit of fresh whole blood. Because plasmatic factors in fresh whole blood may be responsible for this improvement, a study was designated to evaluate the effect of transfusing fresh plasma on platelet function after cardiac operations. Forty patients undergoing cardiopulmonary bypass were randomized to receive either fresh plasma or the fresh packed cell fraction. Administration of packed cells increased platelet number (118 +/- 8.5 to 154 +/- 7.6 x 10(9)/L, p less than 0.05), shortened bleeding time (7.57 +/- 0.4 to 4.0 +/- 0.3 minutes, p less than 0.05), and improved platelet aggregation in response to collagen and epinephrine (32% +/- 4.7% to 50% +/- 5.6% and 37% +/- 5.8% to 50% +/- 5.8%, respectively, p less than 0.05). Fresh plasma, however, neither increased platelet number nor improved bleeding time or platelet aggregation. Each group later received the remainder of the blood unit, with similar results. The results suggest that improvement of platelet function in patients receiving fresh whole blood after cardiac operations is not related to plasmatic factors. Therefore the massive use of fresh frozen plasma in patients after cardiopulmonary bypass should be reconsidered.

Bleeding Time↗
PubMed1989

Right ventricular pressure dynamics after operation for pulmonary stenosis.

Right ventricular pressure dynamics were monitored during the first 24 hours after operation for relief of pulmonary stenosis in 9 patients with dysplastic pulmonary valves who underwent total valvectomy. Rather than the expected immediate drop in pressure after total removal of the obstruction, right ventricular pressures required 18 to 24 hours to decrease to physiological values. In 7 patients, the pressures decreased steadily, but in 2, there was an increase in pressure immediately postoperatively, followed by a gradual decrease.

Adult↗
PubMed1989

Assessment of adverse drug events during the clinical investigation of a new drug.

Identification and documentation of adverse drug events (ADEs) is an essential prerequisite for the evaluation of the therapeutic value of drug treatment. The present article focuses on the methods used to elicit ADEs during the early drug development phase. These methods vary in the sources of information (patient or physician) used to identify and document ADEs and in the areas (e.g., general scales or special motor performance scales) studied for ADEs.

Documentation↗
PubMed1989

The outcome of surgical treatment of hypertrophic obstructive cardiomyopathy. Experience over 15 years.

From 1972 through 1987, 115 patients between the ages of 1 and 83 years (mean, 44.5 years) underwent operation for hypertrophic obstructive cardiomyopathy. Methods of relief of left ventricular outflow obstruction were septal myectomy/myotomy (n = 109), mitral valve replacement (n = 4), and myectomy/myotomy plus mitral valve replacement (n = 2); concomitant procedures included coronary artery bypass (n = 19) and aortic valve replacement (n = 9). Systolic gradient (peak-to-peak) from the left ventricle to the aorta decreased from 70 +/- 38 mm Hg (mean +/- standard deviation) to 9 +/- 11 mm Hg. There were six hospital deaths, for an overall operative risk of 5.2%; one death occurred among 83 patients less than age 65 years (operative risk, 1.2%), and five deaths occurred in 32 older patients (operative risk, 15.6%; p = 0.008 for difference between age groups). Four (22.2%) of 18 patients with a residual gradient greater than 15 mm Hg died, compared with two (2.1%) of 97 patients with a lower gradient (p = 0.003). Follow-up ranged from 0.5 to 16 years (mean, 5.1 years), and 5-year actuarial survival rate, including hospital deaths, was 84% +/- 4%. The 5-year survival rate was decreased in patients who had operative procedures other than myectomy/myotomy (69% versus 91%, p less than 0.005) and in patients aged 65 years or older (54% versus 93%, p less than 0.005). No correlation was found between preoperative symptoms, functional class, left ventricle-aorta pressure gradient, or mitral valve insufficiency and operative or late mortality. Preoperative symptoms were relieved in 57 (76%) of 75 patients with dyspnea, 49 (83%) of 59 patients with angina, and 22 (96%) of 23 patients with syncope. This experience confirms the effectiveness of operation for relief of symptoms in patients with the obstructive form of hypertrophic cardiomyopathy. The current operative mortality rate is low, especially in patients less than 65 years of age (1.2%). Our experience suggests that incomplete relief of left ventricular outflow obstruction may increase the risk of early postoperative death.

Adolescent↗
PubMed1989

Results of operation for hypertrophic obstructive cardiomyopathy in children and adults less than 40 years of age.

Forty-seven consecutive patients aged 1-38 years underwent operation for hypertrophic obstructive cardiomyopathy (HOCM) between 1972 and 1986. Isolated myectomy-myotomy was performed in 43 patients, three patients underwent myectomy and concomitant aortic valve repair, and one patient underwent concomitant mitral valve replacement. The peak systolic pressure gradient from the left ventricle to the aorta decreased from 70 +/- 33 mm Hg (mean +/- SEM) preoperatively to 10 +/- 15 mm Hg immediately after repair (p less than 0.001). Moderate or severe mitral insufficiency was identified in 16 patients preoperatively and was corrected by myectomy alone in 15. There was no operative mortality; two late deaths occurred during follow-up (median, 5 years; maximum, 16 years) for estimated 5- and 10-year survivals of 97 +/- 2% and 88 +/- 10%, respectively. Reoperation was required for aortic valve replacement (n = 2), remyectomy (n = 2), and permanent pacemaker implantation (n = 3). Preoperative symptoms were relieved in 24 of 29 (83%) patients with dyspnea, in 18 of 19 (95%) with angina, and in six of 10 (60%) with syncope. These results support myectomy-myotomy for symptomatic children and young adults with HOCM. Also, it appears that late survival after myectomy-myotomy in these young patients may be improved over that observed in historical controls treated with medications alone; operation should be considered for asymptomatic children and adults less than 40 years of age with large (greater than 80 mm Hg) left ventricular outflow gradients.

Adolescent↗
PubMed1989

The effect of transfusion of fresh whole blood versus platelet concentrates after cardiac operations. A scanning electron microscope study of platelet aggregation on extracellular matrix.

To evaluate the effect of fresh whole blood transfusion versus platelet concentrates transfusion on platelet aggregation after cardiac operations, 24 patients were randomized to receive either one unit of fresh whole blood (12 patients) or 10 platelet units (12 patients) after cardiopulmonary bypass. Platelet aggregation on extracellular matrix, platelet count, and mean platelet volume were studied preoperatively, at termination of cardiopulmonary bypass, after protamine administration, and after the transfusion of fresh whole blood or after transfusion of each two platelet units. Extracellular matrix produced by cultured bovine corneal cells closely resembles the vascular subendothelial basal lamina, and is an ideal in vitro model in the study of platelet interaction with the subendothelium. Platelet aggregation on extracellular matrix, studied by a scanning electron microscope, was graded from 1 to 4, wherein grade 1 represents nonactivated platelets and grade 4 a mature platelet aggregate. With this grading system, the two groups were similar in preoperative values (3.3 +/- 0.9 versus 3.7 +/- 0.4) and values after cardiopulmonary bypass (1.5 +/- 1.0 in both groups). One unit of fresh whole blood restored platelet aggregation on extracellular matrix to preoperative status (3.0 +/- 1.0), whereas eight platelet units were needed for the same result (3.2 +/- 0.8). One unit of fresh whole blood increased platelet count in a manner similar to that achieved by six platelet units and increased mean platelet volume to a level higher than that achieved by 10 platelet units. These results suggest that the effect of one unit of fresh whole blood on platelet aggregation after cardiopulmonary bypass is at least equal, if not superior, to the effect of 8 to 10 platelet units.

Adult↗
PubMed1988

Overview of postmarketing experience with ofloxacin in Germany.

Clinical trials with ofloxacin have shown that adverse drug events (ADEs) occurred in between 2.4% (Phase II) and 3.1-7.3% (Phase IV) of patients treated and were mostly mild. As with any other drug the true spectrum of rare events can only be fully appreciated after marketing. Since the launch of ofloxacin in June 1985 about 3.5 million patients have been treated in Germany, calculated on the basis of a mean daily dose of 400 mg ofloxacin and a mean duration of treatment of seven days. During these 2.5 years 985 spontaneous national reports of ADEs have been obtained and include rare adverse events (e.g. hallucination, psychotic reaction and shock), not seen in clinical trials. The present status of results from postmarketing surveillance is shown and discussed. The favourable overall risk:benefit ratio of ofloxacin appears unchanged.

Clinical Trials as Topic↗
PubMed1988

The hemostatic effect of transfusing fresh whole blood versus platelet concentrates after cardiac operations.

The major cause of nonsurgical bleeding after cardiopulmonary bypass is delayed recovery of platelet count and function. Recovery of platelet count and function was compared in 27 patients who were randomized preoperatively to receive after cardiopulmonary bypass either 1 unit of fresh whole blood (15 patients) or 10 units of platelet concentrates (12 patients). Platelet count, bleeding time, platelet aggregation (adenosine diphosphate, collagen, epinephrine, and ristocetin) and platelet thromboxane formation were abnormal after cardiopulmonary bypass in all the patients. The increase of platelet count after 1 unit of fresh whole blood (from 115 +/- 32 X 10(9)/L to 148.5 +/- 36 X 10(9)/L) was similar to that achieved by 4 units of platelets (from 140 +/- 61 X 10(9)/L to 171 +/- 60 X 10(9)/L). The increase was doubled after 10 platelet units (from 140 +/- 61 X 10(9)/L to 209 +/- 55 X 10(9)/L). Bleeding time returned to normal values after fresh whole blood or after 8 platelet units. However, platelet thromboxane formation was higher after 1 unit of fresh whole blood than after 10 platelet units (95 +/- 25 versus 46 +/- 35 ng/ml, p less than 0.05), as was platelet aggregation response to collagen and epinephrine. The 24-hour blood loss was smaller in the fresh whole blood group (560 +/- 420 ml versus 770 +/- 360 ml), although the difference was not statistically significant. The results suggest that the hemostatic effect of 1 unit fresh whole blood after cardiopulmonary bypass is at least equal, if not superior, to the effect of 10 units of platelets.

Blood Transfusion↗
PubMed1988

Preservation of the posterior leaflet during mechanical valve replacement for ischemic mitral regurgitation and complete myocardial revascularization.

Between 1980 and 1987, 40 patients with ischemic mitral insufficiency underwent mitral valve replacement (with a mechanical prosthesis) and coronary bypass grafting, 3.5 grafts per patient. The posterior mitral leaflet was preserved in 17 and resected in 23. Five arrived at operation in cardiogenic shock, 15 after recurrent episodes of pulmonary edema, and 20 electively, but in congestive heart failure. Twenty-five had unstable angina, and the remaining had chronic angina. Perioperative and early deaths occurred only in patients with an ejection fraction less than 35%. None of the 21 patients with an ejection fraction greater than 35% died, whereas eight of 19 with an ejection fraction less than 35% died, whereas eight of 19 with an ejection fraction less than 35% died (p less than 0.001). When causes of death in patients with an ejection fraction less than 35% were studied, operative and early mortality was zero of seven with preservation of the posterior mitral leaflet versus eight of 11 with excision of the leaflet (p = 0.035). We concluded that the high mortality in mitral valve replacement for ischemic mitral insufficiency is linked to an ejection fraction less than or equal to 35% and, in this particular group of patients, is due to the surgical destruction of the left ventricular chordae tendineae supportive apparatus. Preservation of this apparatus by preservation of the posterior mitral leaflet drastically reduces operative and early mortality. Preoperative cardiogenic shock, left ventricular aneurysmectomy, and multiple grafting (up to five grafts per patient) did not increase the risk of operation. Extensive revascularization (3.5 grafts per patient) provides improved long-term results.

Aged↗
PubMed1988

Relationship of right and left ventricular negative diastolic pressures, hypercontractility, and relief of outflow tract obstructions.

Continuous postoperative right and left ventricular diastolic pressures were measured in 12 consecutive patients undergoing pulmonic valvotomy and in 13 consecutive patients undergoing membranectomy and myectomy for discrete subaortic stenosis. All 25 patients had positive preoperative diastolic ventricular pressures. Negative ventricular diastolic pressure was detected immediately postoperatively in all 25. The lowest left ventricular negative diastolic pressure was -38 mm Hg, and the lowest right ventricular negative diastolic pressure was -28 mm Hg. Intravenous administration of volume (blood) reduced the right ventricular negative diastolic pressure significantly (from -14.8 +/- 9.2 to -6.4 +/- 6.8 mm Hg, p less than 0.001) and decreased right ventricular rate of pressure rise from 1100 +/- 320 to 380 +/- 180. Left ventricular negative diastolic pressure was not significantly affected (from -17 +/- 11 to -14.7 +/- 11 mm Hg). Left ventricular negative diastolic pressure disappeared spontaneously 6 to 9 hours postoperatively in association with a spontaneous decrease of left ventricular rate of pressure rise (from 3450 +/- 610 to 2100 +/- 660 mm Hg/sec). We conclude that negative right and left ventricular pressures are common findings immediately after surgical relief of outflow obstructions. Hypercontractility is the main reason for these phenomena. Volume load reduces the right ventricular negative diastolic pressure, but has insignificant effect on left ventricular negative diastolic pressure. The pathogenesis of the hypercontractility is discussed.

Aortic Valve Stenosis↗
PubMed1988

The perioperative fate of residual gradients after repair of discrete subaortic stenosis and time-related blood levels of catecholamines.

UNLABELLED: The fate of the residual peak systolic left ventricular-aortic gradient was studied perioperatively in 14 patients with membranous discrete subaortic stenosis. In nine (group A) the initial postrepair left ventricular-aortic gradient was greater than 35 mm Hg (mean 56.8 +/- 13.4), and in five (group B) there was no significant postoperative gradient (mean 15.3 +/- 3.2 mm Hg). The operation included membranectomy and myectomy. Peak left ventricular-aortic pressure gradient, endogenous levels of norepinephrine, peak rate of rise of left ventricular pressure, cardiac index, systemic vascular resistance, heart rate, and central venous pressure were recorded at the end of cardiopulmonary bypass and in 3-hour intervals for the next 9 hours. In group A during that period there was a 67% reduction in peak systolic left ventricular-aortic gradient (from 56.8 +/- 13.4 to 18 +/- 14 mm Hg, p less than 0.001). Concomitant reduction in the initial endogenous norepinephrine level was observed (from 982.1 +/- 181 to 422.6 +/- 109 pg/ml, p less than 0.001). A consistent linear relationship between norepinephrine levels and peak systolic left ventricular-aortic gradient was found (r = 0.78). Systolic left ventricular pressure decreased from 174.2 +/- 24.8 to 113.8 +/- 14.7 mm Hg (p less than 0.001). Marked reduction in peak rate of rise of left ventricular pressure (from 3455 +/- 636 to 2161 +/- 680 mm Hg/sec, p less than 0.001) was observed. Cardiac index increased and systemic vascular resistance decreased during the study period (from 2.11 +/- 0.2 to 3.07 +/- 0.26 L/min, p less than 0.001, and from 2172 +/- 331 to 1233 +/- 202 dynes/sec/cm-5, p less than 0.001, respectively). There were no significant changes in heart rate (p = not significant) and central venous pressure p = not significant). CONCLUSION: Some of the residual perioperative left ventricular-aortic gradients in patients with discrete subaortic stenosis undergoing repairs are dynamic and transient, and are probably related to increased postoperative sympathetic activity.

Adolescent↗
PubMed1987

Parathyroid sonography: diagnostic accuracy related to shape, location, and texture of the gland.

The sonographic features of 51 pathological parathyroid glands detected pre-operatively were analysed. Atypical texture was found in 23.5% and variation in shape in 15.6% of the cases. Cystic parathyroid glands are difficult to differentiate from thyroid cysts, and may be the cause of false positive diagnosis, as in three cases in this series. Topographic assessment showed a relatively low sensitivity in detecting disease in the right upper gland (50%) and in the upper mediastinum (70%). The decreased accuracy in these regions is probably because of the particular anatomical location of the right upper gland and sonographic limitations in screening the mediastinal region. Awareness by the radiologist and surgeon of the variations in texture and location may influence both diagnosis and intraoperative detection of the abnormal parathyroid gland.

Humans↗
PubMed1987

Side effects of ofloxacin in clinical trials and in postmarketing surveillance.

Data derived from clinical trials of ofloxacin in 15,962 patients show that the incidence rate of adverse drug events was 4.27 per 100 patients. Symptoms were generally mild and related to the gastrointestinal tract, nervous system or hypersensitivity reactions in rank order. On the other hand, spontaneous reports obtained during postmarketing surveillance involving 1.5 million patients showed that the most frequent adverse drug events were related to the nervous system; next in order of frequency were hypersensitivity reactions and gastrointestinal symptoms. A comparison of the data obtained from clinical trials and postmarketing surveillance revealed no change in the favourable overall benefit:risk ratio of ofloxacin. Possible reasons for the different patterns of adverse drug events are discussed.

Anti-Infective Agents↗
PubMed1987

Inaccuracy of radial artery pressure measurement after cardiac operations.

The phenomenon of a pressure gradient between central and radial arteries was evaluated in 48 patients immediately after coronary artery bypass operations. All were in stable hemodynamic condition, none receiving catecholamine support. In eight patients (Group A) mean femoral pressure was significantly higher than mean radial pressure (range 10 to 30 mm Hg). In the remaining 40 (Group B) radial and femoral pressures were equal. Mean cardiac index (thermodilution) was 3.3 +/- 0.68 versus 2.1 +/- 0.4 L/min/m2, systemic vascular resistance 1,181 +/- 218.4 versus 2,049 +/- 501 dynes/sec/cm-5, toe temperature 23.8 degrees +/- 1.2 degrees C versus 24.02 degrees +/- 0.9 degrees C, core temperature 33.9 degrees +/- 0.5 degrees C versus 34.1 degrees +/- 0.6 degrees C, mixed venous oxygen saturation 78% +/- 3% versus 62% +/- 5%, and peak radial dP/dt 1,485 +/- 366 versus 2,028 +/- 392 in Groups A and B, respectively. These data indicate, first, that the low radial pressures measured in Group A patients did not represent the true central aortic pressures; that is, they were false. Second, these low pressures had nothing to do with compromised cardiac function; rather, they were due to peripheral constriction and volume factors and also probably to proximal shunting. It is therefore recommended that while the chest is still open, if a discrepancy exists between a low radial artery pressure, a high palpable aortic pressure, and a satisfactory cardiac contraction, a femoral cannula for pressure measurement should be inserted. Treatment is by blood infusion until the femoral-radial gradient has been abolished.

Arteries↗