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B H Walpoth

Publications and source records attributed to B H Walpoth.

35 records · Page 2Linked to original sources
PubMed1996

[Differential diagnosis of circulatory failure in hypothermic avalanche victims: retrospective analysis of 32 avalanche accidents].

In avalanche accidents the cause of cardio-respiratory arrest (asphyxia, hypothermia, trauma) is difficult to determine in the field but may be important (high number of victims, limited number of rewarming places). 32 avalanche accidents (16 survivors/16 deaths) were therefore reviewed retrospectively. In 19 patients with cardiorespiratory arrest, asphyxia was frequent (17 patients, 89%) hypothermia was rare (two patients, 11%). The cooling rate between the accident and the arrival at the hospital was 3.0 degrees C/h. (range 0.75-5.8). The core temperature at arrival in the hospital was dependent on the time spent buried under the snow (survivors) and total time (nonsurvivors). The maximal cooling rate under the snow was estimated at 8 degrees C/h. Cardiorespiratory arrest in hypothermic patients without asphyxia seems only to be possible after being buried for at least 1 h. under the snow. Serum potassium was elevated in most cases of asphyxia.

Accidents↗
PubMed1996

Intraoperative internal mammary artery transit-time flow measurements: comparative evaluation of two surgical pedicle preparation techniques.

OBJECTS: Myocardial revascularization is performed preferentially with internal mammary artery grafts. Pedicle preparation and pharmacologic vasodilatory treatment vary greatly. Objective measurements are difficult since peripheral and later coronary vascular resistance and possible competitive flow of the native bypassed coronary artery will influence the results significantly. Our objectives were: (1) measurement of internal mammary artery graft flow with the transit-time flow technique; (2) comparison of two surgical take-down techniques (skeletonizing vs standard pedicle preparation); (3) quantitation of transit-time flow compared to the free pedicle flow and (4) the vasodilatory effect of papaverine on internal mammary artery flow. METHOD: Consecutive elective cases of coronary artery bypass grafting, performed by two surgeons using routinely either skeletonizing of the internal mammary artery (group A, n = 10) or classical pedicle preparation technique (group B, n = 10), were studied prospectively. Anesthesia, cardiopulmonary bypass and operative data were otherwise comparable; likewise, hemodynamic parameters showed no statistical differences between the two groups. Transit-time flow (CardioMed, Medi-Stim, Norway) was measured at the following time points: beginning (1) and end of take-down (2); after papaverine soaking: before (3) and on cardiopulmonary bypass (4); free flow into a beaker (5); after anastomosis; on (6) and off cardiopulmonary bypass (7). RESULTS: Measurement of mean flow showed the following results: (1) severe vasoconstruction of the internal mammary artery was detected in both groups regardless of the preparation technique (occurring earlier in group A); (2) papaverine soaking caused a moderate flow increase (up to 40%); (3) with corresponding cardiopulmonary bypass flow (4.4 vs. 4.1 l/min in group B) a higher free flow in group A was evident (67.7 vs. 50.7 ml/min); (4) after coronary grafting, transit-time flow showed no significant differences between the two groups and (5) using a 3 mm probe, a linear correlation was demonstrated between transit-time flow and simultaneously measured free flow (r = 0.89). CONCLUSION: Intraoperative transit-time flow measurement is a reliable method for assessing internal mammary artery and coronary artery bypass flow; considering the simple technical application, the procedure may be regarded as a valuable instrument of quality control.

Blood Flow Velocity↗
PubMed1994

Assessment of hypothermia with a new "tympanic" thermometer.

OBJECTIVE: Rapid and accurate core temperature measurement is vitally important in trauma patients, especially in those with accidental hypothermia. We tested a new aural thermometer to measure "tympanic" temperatures and assessed its accuracy during normothermic and hypothermic cardiopulmonary bypass. METHODS: Tympanic, esophageal, and blood temperatures were compared in 10 patients undergoing open-heart surgery. In addition, the stability and reaction time of the tympanic thermometer was evaluated in 5 volunteers in a cold room, with and without facial fanning. RESULTS: We observed a good linear correlation between tympanic and esophageal (r = 0.96) and blood (r = 0.81) temperature measurements during normothermia and hypothermia. There was no evidence of iatrogenic ear lesions in any of the patients. In the cold-room tests, stability was excellent and the time for adjustment of tympanic temperature measurement was about 2 min (with and without facial fanning). CONCLUSION: The new tympanic thermoprobe is a simple, fast, and reliable device for measuring core temperature. The device was designed particularly for, and may be useful for, patients suffering from accidental hypothermia.

Adult↗
PubMed1994

Hemofiltration during cardiopulmonary bypass: quality assessment of hemoconcentrated blood.

UNLABELLED: Hemofiltration is often used during cardiopulmonary bypass (CPB) for water removal. In a prospective random study 11 patients undergoing elective coronary artery surgery with hemofiltration during CPB were observed and compared to 11 patients without filtration. The quantitative and qualitative aspects of blood before and after filtration while still on CPB and until the first postoperative day were assessed. Intra- and postoperative volume requirements, standard hematology and chemistry, as well as hemolysis, complement activation, and coagulation factors were analysed at nine sequential points in time. RESULTS: There were no significant differences in pre- and postoperative patient data between the two groups except that the majority of patients in the study group (55%) were anticoagulated and required a significantly longer CPB time with higher doses of protamine and had higher postoperative drainage (2.9 vs. 1.4 L). Intra- and postoperative hemoglobin concentrations, transfusion and volume requirements were similar in both groups. 927 ml of plasma water were filtered during CPB within 4 min 20 s without hemodynamic changes or electrolyte imbalance. Hemoglobin and protein concentrations increased significantly during hemofiltration (Hb increases 3.6 g/dl). Hemolysis and activated complement fractions were elevated during CPB but showed no further increase during filtration; in contrast C4a, C5a, and prothrombin F1 + 2 increased significantly after cessation of CPB. In conclusion, hemofiltration during CPB is a safe and efficient method for water removal and for concentration of red blood cells and proteins without adverse effects on the patient's hemodynamics, blood quality, and volume requirements. More especially, no negative influence of hemofiltration could be determined with regard to activation of the coagulation and complement system.

Blood Cell Count↗
PubMed1993

Experimental assessment of thrombogenicity in vascular prostheses before and during prostaglandin E1 treatment.

The effect of prostaglandin E1 (PGE1; Prostavasin), a powerful platelet blocking agent, was assessed on various new synthetic or biological prostheses in a 6-min in vivo extra corporal arterio-venous (AV) shunt. In eight anaesthetised and heparinised minipigs (weight 25.1 +/- 1.9 kg) the following materials were tested before and during PGE1 infusion (alprostadil-alpha-CD; 40 micrograms/50 ml NaCl/50 min or 0.8 microgram/min): PTFE, (Gore-tex, TW, 4 mm ID); Xenograft, Biologic (Solcograft, 5 mm ID), (non-porous) and Dacron (Atrium, 4 mm ID); polyurethane 1 (Braun-Melsungen, 4 mm ID); polyurethane 2 (S. Gogolewski, 4 mm ID), (porous). Technetium-labelled platelet deposition and blood flow were measured; morphology was assessed by scanning electron microscopy (SEM) and histology. Compared to control levels, PGE1 infusion had a significant systemic effect on mean arterial pressure required by the protocol (MAP 82.6 vs. 66.6 mm Hg; p < 0.001) and flow (173.6 vs. 134.8 mm/min; p < 0.001). Standardised platelet counts per area showed a marked overall decrease from 197 to 130 counts/min/mm2; NS). The morphological assessment by SEM showed a slight increase of surface cellular deposition (score: 6.7 vs. 8.3), the histology score being unchanged (3.9 vs. 3.7). Looking at deposition of platelets for each prosthesis, the porous materials showed a net improvement after PGE1 treatment as compared to non-porous materials. We conclude that PGE1 may be of benefit by reducing platelet deposition in synthetic porous vascular prostheses in the early phase.

Alprostadil↗
PubMed1993

Current problems with autologous blood supply.

OBJECTIVE: The purpose of the present study consists in an updated review of recent progress in the field of autologous blood supply. At different medical centers, autologous blood products are collected by quite different procedures, which may be applied during pre-, intra- and/or postoperative periods according the technical possibilities of the local blood supply systems. The products are very different, consisting in whole blood, red cell concentrates, platelet concentrates, fresh-frozen plasma (from whole blood and from plasmapheresis), as well as in wound and drainage fluid and in washed red cell concentrates. Iron therapy against autologous blood donation--or against surgical bleeding-induced anemia--is now well established, but it is unclear whether it should be given perorally or intravenously. In addition, erythropoietin substitution may be necessary for some but not all patients. DATA SOURCES: For our review we have used as sources, beyond our own published reports, studies devoted to clinical experience as well as to pathophysiological aspects of blood donation. RESULTS AND CONCLUSIONS: It becomes apparent that the practice of autologous blood supply has now reached peripheral hospitals not affiliated with bigger medical centers. Smaller hospitals may share expensive equipment necessary for autologous blood collection. Such progress contrasts with persistent uncertainties regarding iron and erythropoietin substitution.

Blood Component Removal↗
PubMed1991

[Benefits and side effects of preoperative autologous blood donation in 11 heart surgery patients].

Patients scheduled for cardiac surgery are prone to adverse reactions during blood donation due to hemodynamic instability. 11 selected patients donated three units of red blood cell concentrates and three units of fresh frozen plasma (FFP) preoperatively in 11-day intervals under careful hemodynamic monitoring. 24 hours preoperatively autologous plasmapheresis (500 ml) was carried out in 10 patients at bedside. No complications were seen in any patients. The patients' mean hemoglobin concentrations were 142 +/- 11, 133 +/- 6, 128 +/- 7 and 126 +/- 7 g/l (mean +/- 1 SD) before each autologous blood donation and before the plasmapheresis respectively. No significant changes were noted in major hematological and chemical screening tests. Serum iron, iron-binding capacity and ferritin levels remained within the normal range. Due to additional perioperative blood saving methods, such as reinfusion of centrifuged oxygenator-blood (559 +/- 119 ml) and shed mediastinal blood (518 +/- 353 ml), only two patients needed additional transfusion of 1 homologous red cell unit each. On average 2.18 autologous red cell concentrates were retransfused per patient.

Blood Chemical Analysis↗
PubMed1991

Differentiation of cardiac ischemia and rejection by nuclear magnetic spectroscopy.

Nuclear magnetic resonance (NMR) criteria of early cardiac rejection are similar to those seen in myocardial ischemia, that is, a reduction of high energy phosphatases (Pc; ATP) and an increase of inorganic phosphates (Pi). Our aim was to assess in vivo changes of phosphorous spectroscopy (31P) induced by cardiac rejection and myocardial ischemia in the same animal. Heterotopic heart isografts (n = 5) and untreated allografts (n = 5) were examined at seven days on a two tesla wide-bore magnet with a surface coil. Subtotal global ischemia was produced for sequential NMR measurements, followed by heart excision for histological rejection grading (Billingham). Results 1. Isograft served as controls and showed normal energy-rich phosphate compounds and pH. 2. Rejecting (moderate to severe) allografts showed a decrease of Pc/Pi and beta-ATP/Pi ratio compared with isografts. However no significant pH drop could be detected. 3. Induced ischemia was confirmed by marked ECG-ST elevation and showed a significant early global myocardial acidosis (pH less than 6.9) particularly in severe prolonged ischemia (p less than 0.05). 4. Using 31P NMR techniques, ischemically induced changes were similar in isografts and allografts with a trend towards a more pronounced extent in the latter groups. In conclusion, magnetic resonance spectroscopy (31P and pH) allows in vivo differentiation between cardiac rejection and acute myocardial ischemia.

Acute Disease↗
PubMed1990

[Quantitative and qualitative analysis of various blood-preserving measures in heart surgery].

We assessed quantitative aspects of blood salvage retrospectively in 270 consecutive coronary bypass patients over one year. They were assigned either to group A (n = 10, Cellsaver [Haemonetics]), B (n = 189, centrifugated oxygenator blood), C (n = 107, retransfusion of shed mediastinal blood) or D (n = 74, combination of method B and C). In addition, blood quality was studied prospectively in group A (n = 5), B (n = 10) and C (n = 10) and each group compared to a control group. Results (mean values/patient) were: Blood salvage with A yielded 570 +/- 230 ml (hematocrit = 50%), B 509 +/- 156 ml (69%) and C 593 +/- 430 ml (26%). The required homologous blood products, i.e. packed cells (PC) and fresh frozen plasma (FFP) diminished significantly when combined autologous blood salvage was used (PC 6.0 +/- 3.4 vs 3.4 +/- 1.9, p less than 0.05; FFP 3.4 +/- 3.8 vs 2.6 +/- 3.0). Autologous erythrocyte function assessed by 2,3DPG was normal in all three methods (range 14.77-16.03 mumol/gHb). ATP was nearly normal in A (3.34 +/- 0.45 mumol/gHb), reduced by 20% in B (3.21 +/- 1.14 mumol/gHb) and by 30% in C (2.56 +/- 0.78 mumol/gHb) compared to the corresponding preoperative patient value. Hemolysis (free plasma hemoglobin) (was elevated in A (63 +/- 7 mg/dl), B (202 +/- 57 mg/dl) and C (211 +/- 44 mg/dl). However, no increase of free plasma hemoglobin was encountered in our patients after retransfusion of either A, B or C. No side effects were detected and bacteriology remained negative in all examined blood samples in C.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1990

Accidental deep hypothermia with cardiopulmonary arrest: extracorporeal blood rewarming in 11 patients.

Sixteen patients (age 13-53 years) with accidental deep hypothermia have been rewarmed in our clinic during the last 10 years, 14 by femoro-femoral cardiopulmonary bypass (CPB) of whom 11 had a cardiopulmonary arrest (asystole in 5 and ventricular fibrillation in 6). On admission, the latter were clinically dead showing wide non-reactive pupils and being supported by ventilation and external heart massage. In the survivors, the mean length of cold exposure was 4.4 h (2-5.5 h) and mean arrest interval until initiation of CPB was 2.5 h (1.4-3.7 h). Rectal temperature on admission ranged from 17.5 degrees C to 26 degrees C (mean 22.5 degrees C). The causes for hypothermia were fall into a crevasse (5), avalanche (1), drowning (2) and cold exposure (3) including 2 suicide attempts. Results are summarized in the following table: [table: see text] Eight of the 11 patients with deep hypothermia and cardiac arrest were rewarmed and resuscitated successfully with CPB. Three patients, including 2 cases of asphyxia (avalanche and drowning), could not be weaned from CPB despite adequate rewarming. The other drowned patient (53 years) died on the 3rd postoperative day (POD) from ARDS. The main complication was pulmonary edema (57%) and transient neurological deficits. All survivors became conscious during the first POD and resumed, their professional activity. We conclude that patients with accidental deep hypothermia and even prolonged cardiopulmonary arrest should be rewarmed and resuscitated rapidly by cardiopulmonary bypass. These measures are very promising particularly if the cause of accident and the circumstances suggest that cardiopulmonary arrest was induced by hypothermia alone without other asphyxiating mechanisms.

Adolescent↗
PubMed1990

[Evaluation of recent vascular prostheses in the arteriovenous shunt].

Prosthetic vascular replacement materials are still suboptimal especially for distal peripheral and coronary bypass grafts due to the small caliber and high occlusion rates. Therefore new vascular grafts have been assessed with respect to blood compatibility, thrombogenicity and host pretreatment. In 12 heparinized minipigs (25 kg), a total of 120 small caliber grafts (i.d. 3.0 mm) were perfused (6 min) in a femoro-femoral arteriovenous shunt (AVS). Materials included: Dacron (Atrium), PTFE (Gore), Polyurethanes (PU), Auto- and Xenografts. Animals were treated preoperatively with fishoil (3 g EPA/QD x 3 weeks = group I), perioperatively with prostaglandins (PGE1 = group II) or with fishoil and graft incubation in plasma proteins (= group III) and compared to controls without pretreatment (= group 0). We measured flow, deposition of marked thrombocytes (HMPAO-Tc* per area and per weight). - Blood flow was similar in AVS for all groups and materials (168 +/- 86 ml/min, p = NS). There was no significant correlation in deposition of marked thrombocytes and host pretreatments (group 0: controls = 7356 counts/area, group I: fishoil = 6807. group II: PGE1 = 7864). However graft incubation in plasma proteins significantly lowered deposition of marked thrombocytes (1766 in group III vs. 7356 in group 0: p less than 0.05). And significant differences of thrombocyte counts where found between the different materials: Autografts less than PTFE less than Xenografts less than Small Pore PU less than Dacron less than Large Pore PU.--AVS is a useful tool to determine early thrombogenicity in prosthetic vascular replacement materials and to assess the effect of different host pretreatments.

Animals↗
PubMed1990

[Retransfusion of thoracic drainage blood: qualitative analysis].

In a prospective randomized study 10 patients received their shed mediastinal blood after elective coronary artery bypass surgery and were compared to 10 control patients without retransfusion. The quality assessment can be summarized as follows (mean +/- 1 SD): 1. Hemoglobin concentration of the shed blood was 9.6 +/- 1.45 g/dl. 2. The energy rich phosphate compounds of the shed blood erythrocytes were 2.6 +/- 0.8 mumol/gHb ATP (70% of the patients preoperative value) and 14.8 +/- 4.2 mumol/gHb 2.3-DPG (normal). 3. Proteins, immunoglobulins and especially albumin in the shed blood were not significantly different from the patients own values. 4. No electrolyte changes, safe for a slight increase in potassium (5.7 +/- 0.7 mmol/l). 5. The activated clotting time of the patient did not change during retransfusion. 7. Plasma free hemoglobin was elevated to 211.1 +/- 44.3 mg/dl in the shed blood; however, no significant increase could be noted in the retransfused patients and no hemoglobinuria occurred. Postoperative retransfusion of shed mediastinal blood is a simple and safe method of autologous transfusion early after cardiac surgery and should be combined with other methods of blood salvage. The qualitative advantages of blood retransfusion consist in the absence of storage damage and in the preservation of autologous proteins and immunoglobulins.

Blood Chemical Analysis↗
PubMedDate not supplied

A comparison study of self-expandable stents vs balloon angioplasty alone in femoropopliteal artery occlusions.

In a group of 26 patients percutaneous transluminal (balloon) angioplasty (PTA) and stents (Wallstents) were applied and in another 26 matched patients PTA alone was used as primary treatment for femoropopliteal occlusions of 3 cm or longer. Five patients with stents showed early thrombosis necessitating catheter thrombolysis and/or thrombus aspiration. Ten patients had recurrent stenoses within 12 months, mostly due to neointimal hyperplasia. Following three late catheter reinterventions, a cumulative secondary patency rate of 69% was achieved after 12 months. The group of patients treated by PTA alone showed a 12 months patency rate of 65% without reinterventions. In 8 other patients, stents were inserted for recurrent obstructive or PTA-resistant lesions, and similar results as with the stents above were obtained. Thus, these stents do not improve primary results of PTA in femoropopliteal occlusions but may be useful secondarily after unsuccessful PTA.

Aged↗
PubMedDate not supplied

Magnetic resonance spectroscopy for assessing myocardial rejection in the transplanted rat heart.

Traditionally, detection of heart rejection after heart transplantation is based on histologic grading of endomyocardial biopsy specimens. The value of magnetic resonance spectroscopy for determining heart rejection was assessed in rejecting and nonrejecting isografts and allografts using energy-rich phosphate spectroscopy. In 46 rats a heterotopic abdominal heart transplantation was performed, and animals were divided into the following groups: six isografts (no rejection), five untreated allografts (severe rejection), and 35 immunosuppressed allografts (mild to moderate rejection). One week after transplantation magnetic resonance spectroscopy was performed, and data were correlated to histologic findings (rejection grades according to Stanford and the New International Working Formulation classifications and relative volume of viable myocardium). Magnetic resonance spectroscopy allows detection of moderate to severe rejection with significant alterations in the energy-rich phosphates such as a decrease in the ratio of phosphocreatine/inorganic phosphate, phosphomonoester/inorganic phosphate, and beta-adenosine triphosphate/inorganic phosphate. A significant correlation was found between spectroscopic changes (phosphocreatine/inorganic phosphate) and histologic rejection (correlation coefficient r = 0.47, p < 0.005) and/or the amount of relative volume of viable myocardium and phosphocreatine/inorganic phosphate (r = 0.58) or beta-adenosine triphosphate/inorganic phosphate (r = 0.63), respectively. In conclusion magnetic resonance spectroscopy permits detection of moderate to severe degrees of heart rejection with a sensitivity of 85% and a specificity of 61%. Changes in the energy-rich phosphates correlate with the histologic grading of heart rejection and the relative volume of viable myocardium. Magnetic resonance spectroscopy appeared to be a valid technique for detecting myocardial rejection after heart transplantation in the reported experimental model.

Adenosine Triphosphate↗