Biomedical subjects

H B Kram

Publications and source records attributed to H B Kram.

At least 37 records · Page 2Linked to original sources

PubMed1991

Late results of two hundred seventeen femoropopliteal bypasses to isolated popliteal artery segments.

A 10-year-experience of 217 femoropopliteal bypasses to isolated popliteal artery segments in 207 patients is reported. Thirty-three femoropopliteal bypasses (15%) were performed with reversed saphenous vein and 184 (85%) with polytetrafluoroethylene grafts. Operative indications were gangrene in 121 (56%), nonhealing ulceration in 40 (18%), ischemic rest pain in 51 (24%), and claudication in 5 (2%) cases. The 5-year primary graft patency rate of these bypasses was 59% (reversed saphenous vein, 74%; polytetrafluoroethylene, 55%; p less than 0.05), the secondary 5-year graft patency rate was 61% (reversed saphenous vein, 79%; polytetrafluoroethylene, 56%; p less than 0.05), and the 5-year limb salvage rate was 78% (reversed saphenous vein, 78%; polytetrafluoroethylene, 78%). The 30-day operative mortality rate was 10%, and the 5-year patient survival rate was 38%. Eleven patients (5%) required lower extremity amputation because of progressive gangrene or extensive infection despite a patent bypass to an isolated popliteal artery segment. We conclude that femoropopliteal bypasses to isolated popliteal artery segments (1) have acceptable 5-year graft patency and limb salvage rates; (2) should be performed with reversed saphenous vein grafts when possible; (3) may be performed with polytetrafluoroethylene grafts if necessary, with a resulting limb salvage rate equal to that of reversed saphenous vein grafts; and (4) require sequential extension to an infrapopliteal artery in up to 20% of patients. In addition, the presence of an isolated popliteal artery segment is associated with a high operative mortality rate and limited life expectancy because of coronary artery disease.

Adult↗

PubMed1991

Prospective, randomized comparison of ringed and nonringed polytetrafluoroethylene femoropopliteal bypass grafts: a preliminary report.

Kinking and compression with knee flexion are thought to be one cause of failure of below-knee polytetrafluoroethylene femoropopliteal bypass. To prevent this problem polytetrafluoroethylene grafts externally supported with rigid rings have been developed. The present randomized, prospective study compared ringed and nonringed polytetrafluoroethylene grafts in 122 patients who underwent femoropopliteal bypass for severe limb ischemia. Patients were well matched for surgical indications and risk factors. There was no significant difference in the 3-year graft patency rate of ringed versus nonringed polytetrafluoroethylene femoropopliteal bypasses (74% vs 68%, p = 0.5). Similarly, no significant differences were found in the 3-year graft patency rates of ringed versus non-ringed above-knee (82% vs 74%, p = 0.5) or below-knee polytetrafluoroethylene femoropopliteal bypasses (68% vs 59%, p = 0.5). The 3-year graft patency rate of all above-knee polytetrafluoroethylene femoropopliteal bypasses was slightly greater than that of below-knee polytetrafluoroethylene femoropopliteal bypasses (76% vs 62%), but this difference was not statistically significant (p = 0.25). The 3-year limb salvage rate with ringed polytetrafluoroethylene grafts was 92% compared with 79% for nonringed polytetrafluoroethylene grafts, but this difference was not statistically significant (p = 0.25). Data to date from this study fail to support the recommendation that ringed polytetrafluoroethylene grafts be used preferentially over conventional polytetrafluoroethylene grafts in patients who require femoropopliteal bypass with a synthetic graft.

Adult↗

PubMed1991

Spraying of aerosolized fibrin glue in the treatment of nonsuturable hemorrhage.

In the present report, the authors describe the use of aerosolized fibrin glue (FG) to achieve hemostasis in patients with nonsuturable hemorrhage. The multicomponent FG was sprayed on bleeding tissues with a dual chamber spray head that allowed simultaneous application and mixing of fibrinogen and thrombin on the tissue surface. Sterile propellant gas was passed through tubing to the spray head and independently controlled, allowing for drying of the tissue surface immediately before FG application. This technique was found to be effective in achieving hemostasis of parenchymal organs, retroperitoneal surfaces, and skin graft donor sites. Additional potential applications of this technique include the control of hemorrhage from mediastinal and pleural surfaces.

Aerosols↗

PubMed1991

Clinical algorithm for initial fluid resuscitation in disasters.

This article reviews past experience with branch-chain decision trees for fluid resuscitation of various emergency conditions and analyzes the effects of compliance with the algorithm on mortality and shock-related complications. On the basis of this analysis, the authors propose a new algorithm for fluid resuscitation of mass casualties when only palpable systolic blood pressure is available and when blood pressure, hematocrit, central venous pressure, urine output, and arterial blood gases are available.

Algorithms↗

PubMed1991

Evaluation of a blunt and penetrating trauma algorithm for truncal injury.

The authors objective was to develop and test a single branch-chain decision tree for blunt and penetrating truncal injury. Over the 4-month study period there were 979 patients evaluated in the emergency department; 674 of these patients were admitted to the hospital. Thirty-four (5%) of the 674 admitted patients died of truncal injury. The study group consisted of 239 of the most severely injured patients; 41 of these (17%) died. Of the 44 patients managed with major deviations from the algorithm, 27 (61%) died. Only 14 of the 195 patients (7%) whose management complied with the algorithm died. The authors conclude that following the specific management criteria outlined by the algorithm may improve the survival of severely traumatized patients.

Abdominal Injuries↗

PubMed1990

The efficacy of central venous and pulmonary artery catheters and therapy based upon them in reducing mortality and morbidity.

The purpose of this study was to (1) evaluate the relative cost effectiveness of the central venous pressure and flow-directed pulmonary artery catheters used to maintain normal hemodynamic values as therapeutic goals in the control groups vs supranormal values empirically observed in critically ill postoperative survivors in the protocol groups, and (2) to evaluate tissue perfusion and oxygenation in relationship to organ failure and mortality. In two prospective clinical trials there were no significant differences in outcome between the central venous pressure and pulmonary artery control groups that used normal values as therapeutic goals. However, there were marked and significant reductions in morbidity and mortality of the protocol groups using the supranormal cardiac index, oxygen delivery, and oxygen consumption values as goals. The cumulative oxygen debt was less and organ failures were fewer and less severe in the protocol groups than in the control groups.

Cardiac Output↗

PubMed1990

Measurement of tissue perfusion by oxygen transport patterns in experimental shock and in high-risk surgical patients.

Survivors of high-risk general (noncardiac) surgery were observed to have cardiac index (CI) values averaging 4.5 l/min.m2, oxygen delivery (DO2) of greater than 600 ml/min.m2, and oxygen consumption (VO2) of 170 ml/min.m2. In contrast, these values were relatively normal in patients who subsequently died. A very early predictive index based on these observations was found to predict outcome in 94% of high-risk patients. The hypotheses that increased DO2 and VO2 in the survivors represent compensatory physiologic responses and that these values were appropriate therapeutic goals were tested in prospective randomized clinical trials and found to reduce mortality and morbidity significantly. The optimal goals were more easily attained with colloids, red cells, dobutamine, and vasodilators, according to their capacity to improve tissue perfusion, as reflected by increased flow and oxygen transport. The extremely complex interactions between DO2 and VO2 are reviewed.

Animals↗

PubMed1990

Intestinal perforation due to cytomegalovirus infection in patients with AIDS.

Intestinal perforation due to cytomegalovirus (CMV) infection in patients with AIDS is the most common life-threatening condition requiring emergency celiotomy in these patients. The authors describe a patient with AIDS with intestinal perforation due to CMV infection, and review 14 additional cases reported in the English-language surgical literature. The diagnostic triad of pneumoperitoneum on x-ray, evidence or history of CMV infection, and AIDS occurred in 70 percent of patients. The most common site of intestinal perforation was the colon (53 percent), followed in frequency by the distal ileum (40 percent) and appendix (7 percent); perforation usually occurred between the distal ileum and splenic flexure of the colon. Colonoscopy, rather than sigmoidoscopy, is recommended as a screening examination in patients with AIDS suspected of having colonic ulceration due to CMV infection. Multiple biopsies of ulcerated tissue should be obtained. Gross and microscopic analyses of involved intestinal tissue reveal the characteristic findings of ulceration and CMV infection. Despite aggressive therapy, the operative mortality rate in patients with AIDS with intestinal perforation due to CMV infection was 54 percent and the overall mortality rate was 87 percent. Postoperative complications occurred in most patients and consisted mainly of systemic sepsis and pneumonia caused by Pneumocystis carinii infection. An increased awareness of this syndrome by physicians frequently called on to manage patients with AIDS is recommended.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Use of a piezoelectric film sensor for monitoring vascular grafts.

Detection of failing arterial reconstructions requires intensive surveillance by frequent physical examination and noninvasive laboratory testing. However, many grafts fail during the intervals between these examinations. For this reason, we have developed an implantable miniaturized piezoelectric flow detection device whose function can be monitored externally by radiotransmission across the skin. Sensors were constructed from ultrathin polyvinylidene fluoride (PVF2) with piezoelectric activity and attached with silicone fixative to 6-mm polytetrafluoroethylene grafts. Ten of these grafts were placed in mongrel dogs as iliofemoral bypasses. Real time data were acquired from the sensors at a rate of 200 Hz, using a DATAQ A/D data acquisition board and CODAS data acquisition software, while simultaneous blood flow (using an electromagnetic flowmeter) and intraluminal pressure were processed by using separate channels of the same data acquisition board. The data were stored on computer storage media and analyzed by the ASYST software, which allows simultaneous signal curves to be compared using regression analysis. In the resting state, the mean blood flow was 123 +/- 16 mL and the mean intraluminal pressure was 124/78 mm Hg, and there was perfect correlation between the PVF2 sensor and the flowmeter and between the sensor and the intraluminal pressure (correlation coefficient, r greater than or equal to 0.99 and r greater than or equal to 0.93, respectively). A tourniquet was applied to the iliac artery proximal to the graft to reduce the flow to approximately half of the resting state (mean flow after tourniquet: 66 +/- 6 mL/minute). Signal tracings from the three sources showed a remarkable similarity with a very high correlation coefficient (r greater than or equal to 0.99 between sensor and flowmeter and r greater than or equal to 0.92 between sensor and the pressure signal). These preliminary results show that the sensors made from low-profile and low-mass PVF2 material have the potential of being implanted around grafts for long-term, continuous monitoring of graft function. Further studies involving long-term implantation to assess the effect of tissue ingrowth and loss of compliance are necessary before this device can be used clinically.

Animals↗

PubMed1990

Limb loss with patent infra-inguinal bypasses.

To determine systemic and local risk factors that contribute to limb loss despite a patent infra-inguinal bypass graft and how to prevent it, we reviewed 987 patients who underwent infra-inguinal bypasses at our institution. Seventy-five (7.6%) patent grafts failed to achieve a healed foot despite exhaustive attempts to do so and these patients underwent major amputation either above the knee (AKA) or below the knee (BKA). In 525 femoro-popliteal bypasses, there were 38 major amputations (29 BKA; 9 AKA) with a patent graft; in 462 femoro-distal bypasses, there were 37 amputations (22 BKA; 15 AKA) with a patent graft. The remaining 912 patients with limb salvage as well as all the patients with limb loss were evaluated with regard to systemic risk factors, quality of the run-off from the popliteal artery, continuity of the tibial artery into the arch as demonstrated on arteriography, the haemodynamic improvement obtained postoperatively, and the presence and extent of necrosis in the foot. The presence of diabetes, extensive pedal necrosis and advanced infection predispose to limb loss despite a patent lower extremity bypass graft. Patients who lost their limbs despite a functioning bypass to an isolated popliteal segment had significantly less pronounced haemodynamic improvement postoperatively. An early graft extension to a reconstituted tibial or peroneal artery or a direct bypass to a distal tibial or peroneal artery may reduce the incidence of limb loss in this setting. When a patent bypass to an isolated tibial or peroneal artery segment failed to relieve foot ischaemia, limb salvage was achieved by a distal extension to plantar arteries.

Amputation, Surgical↗

PubMed1990

Techniques of splenic preservation using fibrin glue.

Fibrin glue (FG) was used to achieve hemostasis of 16 splenic injuries in 14 patients. The etiologies of injury included five gunshot wounds, two stab wounds, four iatrogenic injuries, and five patients with blunt splenic trauma. The intraoperative blood loss averaged 1.8 +/- 2.4 (SD) liters and patients were transfused 3 +/- 2 units of blood perioperatively. The amount of FG required to achieve splenic hemostasis averaged 11 +/- 8 ml and varied directly with the grade of injury. One patient with a splenic hilar vascular injury (Grade V) underwent splenectomy following failure to achieve complete hemostasis despite the use of 25 ml of FG. All other splenic injuries were successfully managed using less than 25 ml of FG. Postoperative computerized tomographic (CT) scanning, performed in ten patients, was negative for rebleeding or abscess formation. The overall splenic salvage rate was 86%. FG was effective in achieving hemostasis of both superficial and deep splenic injuries. Its use as an adjunct in trauma surgery should result in increased splenic salvage rates compared with that obtained using conventional surgical techniques.

Adult↗

PubMed1990

Significance and management of inflow gradients unexpectedly generated after femorofemoral, femoropopliteal, and femoroinfrapopliteal bypass grafting.

With multilevel arteriosclerosis, some patients undergoing infrainguinal bypass grafting will develop femoral/brachial pressure gradients only after the bypass is performed. We therefore evaluated arteriographically alternate inflow sites and measured the femoral/brachial pressure gradients before and after placement of 87 femorofemoral and 510 femoropopliteal/infrapopliteal bypasses. No prebypass femoral/brachial pressure gradients were present with and without intraarterial papaverine. However, femoral/branchial pressure gradients greater than or equal to 15 mm Hg were observed after the bypass placement in 16 femorofemoral patients and 43 femoropopliteal/infrapopliteal patients. Gradients averaged 28 +/- 8 (SD) (range, 15 to 50) mm Hg. The post femorofemoral bypass gradients were treated by immediate supplementary inflow extension to the aorta (three patients) or an axillary artery (three patients); by postoperative iliac percutaneous transluminal angioplasty (four patients) or by no treatment (six patients with femoral/brachial pressure gradients of 15 to 35 [23 +/- 5] mm Hg). The 43 postfemoropopliteal/infrapopliteal bypass gradients were treated by immediate supplementary inflow extension to the contralateral femoral artery (15 patients), the aorta (8 patients), or an axillary artery (3 patients); by postoperative iliac percutaneous transluminal angioplasty (5 patients) or by no treatment (12 patients with femoral/brachial pressure gradients of 15 to 30 [21 +/- 4] mm Hg). No thrombosis occurred in the 10 femorofemoral bypasses with postbypass femoral/brachial pressure gradients that were treated. One of the six femorofemoral patients with untreated gradients required a subsequent aortic extension, and one thrombosed after 2 years. Of the 12 untreated patients with femoropopliteal/infrapopliteal bypasses one graft occluded early, and two late failures occurred 12 and 18 months later.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1990

Therapy of shock based on pathophysiology, monitoring, and outcome prediction.

High-risk patients who survived general (noncardiac) surgery were observed to have cardiac index (CI) values averaging 4.5 L/min.m2, oxygen delivery (DO2) greater than 600 ml/min.m2, and oxygen consumption (VO2) 170 ml/min.m2 during the first 2 or three days postoperatively. Patients who subsequently died maintained relatively normal CI, DO2, and VO2 values in this period. Values of other variables in survivors and nonsurvivors were not appreciably different. An index based on these observations correctly predicted outcome in 94% in a subsequent prospective study. Two hypotheses: a) that increased flow and oxygen transport represent compensatory physiologic responses to an earlier tissue oxygen debt, and b) that these survivors' values were appropriate therapeutic goals, were tested in prospective randomized clinical trials. The protocol group attained those therapeutic goals. This resulted in significantly reduced mortality and morbidity. Optimal goals were more easily attained with colloids, red cells, and an inotropic agent, dobutamine. Dobutamine was used because, in a prospective crossover clinical trial with dopamine at various doses, dobutamine produced greater increases in flow and flow-related variables. More importantly, it improved tissue perfusion as reflected by greater increases in VO2 and greater reductions in pulmonary and systemic vascular resistance.

Blood Volume↗

PubMed1989

Fibrin glue achieves hemostasis in patients with coagulation disorders.

Fibrin glue (FG), made with highly concentrated human fibrinogen and clotting factors, was used to achieve parenchymal organ hemostasis in patients with disordered coagulation secondary to massive transfusion, chronic disease, and disseminated intravascular coagulation; it was effective in controlling liver hemorrhage in seven patients and in the performance of a splenorrhaphy in one other patient. The coagulation profile was grossly abnormal in all patients, and the mean +/- SD intraoperative blood loss was 5.1 +/- 4.2 L; patients received 14 +/- 10 U of blood perioperatively. The amount of FG required to achieve hemostasis varied directly with the extent of injury and intraoperative blood loss (r = .84), and all patients with a blood loss greater than 4 L required at least 25 mL of FG to stop bleeding. Two patients died postoperatively secondary to cardiac arrest and adult respiratory distress syndrome. Because FG does not depend on adequate platelet or clotting factor levels to be effective, it is especially useful in patients with parenchymal organ hemorrhage and disordered coagulation.

Adult↗

PubMed1989

Prediction of below-knee amputation wound healing using noninvasive laser Doppler velocimetry.

Preoperative laser Doppler velocimetry (LDV) measurements of calf and brachial skin perfusion were performed in 29 patients prior to undergoing below-knee amputation; dual calf measurements on the anterior and posterior skin flaps were routinely obtained. Patients' ages ranged from 24 to 83 years; 16 had diabetes, 13 were smokers, 6 had hypertension, and 2 had known coronary artery disease. Anterior and posterior calf LDV values greater than or equal to 20 mV were associated with successful below-knee amputation wound healing in 25 of 26 patients; all 3 patients with either anterior or posterior calf LDV values less than 20 mV had below-knee amputations that failed to heal. Calculation of calf-brachial LDV indexes did not increase predictive accuracy compared to calf LDV measurements alone, although patients with wounds that failed to heal tended to have lower calf-brachial indexes. Preoperative noninvasive LDV may be used to aid in predicting the likelihood of successful healing after below-knee amputation.

Adult↗

PubMed1989

Diagnosis of traumatic thoracic aortic rupture: a 10-year retrospective analysis.

A 10-year retrospective analysis of 82 patients with suspected thoracic aortic rupture (TAR) due to blunt chest trauma was performed to define which symptoms and signs were helpful in making an early diagnosis. Symptoms and signs associated with TAR included midscapular back pain (in the absence of thoracic spine fracture), unexplained hypotension, upper extremity hypertension, bilateral femoral pulse deficits, and initial chest tube output in excess of 750 mL. Chest roentgenographic signs seen with significantly greater frequency in the 12 patients with TAR than in 70 patients without such rupture included a widened paratracheal stripe (7 patients), deviation of the nasogastric tube or central venous pressure line (5 patients), blurring of the aortic knob (9 patients), abnormal paraspinous stripe (6 patients), and rightward tracheal deviation (5 patients). Mediastinal widening of greater than 8 cm occurred in 11 of the 12 patients with TAR (sensitivity, 92%); its specificity, however, was only 10% (11 true-positive and 63 false-positive results). In patients in hemodynamically stable condition who display these findings, immediate aortography should be considered. The presence of myocardial contusions, intraabdominal injuries, and pelvic fractures also occurred more frequently in patients with TAR. We conclude that a detailed history, physical examination, and chest roentgenography, with rapid progression to aortography in suspicious cases, represent the safest and most reliable approach to patients with TAR.

Accidents, Traffic↗

PubMed1989

Fibrin glue in renal and ureteral trauma.

Fibrin glue (FG) made with highly concentrated human fibrinogen and clotting factors was used to achieve hemostasis of fourteen renal injuries and to seal three ureteral anastomoses in 15 patients. The cause of injury included twelve gunshot wounds, four stab wounds, and one iatrogenic ureteral injury. The mean intraoperative blood loss was 1.6 +/- 1.1 L (SD), and patients received 4 +/- 5 units of blood perioperatively. Utilizing the described techniques, FG was effective in achieving hemostasis and sealing ureteral suture lines against leakage in all cases. There were no cases of renal infection, rebleeding, urinary fistulas, delayed rupture, stone formation, or urinary tract obstruction. Two patients underwent re-exploration for causes unrelated to their renal or ureteral injuries. The use of FG was associated with less reliance on suture redundancy to achieve parenchymal hemostasis and perform ureteral anastomoses. FG sealing of renal and ureteral injuries is a safe and effective technique for controlling hemorrhage and sealing anastomoses. It is effective in the management of both superficial and deep renal injuries.

Adolescent↗

PubMed1989

Testicular oximetry: a new method for the assessment of tissue perfusion and viability following torsion and detorsion.

This study evaluated the use of a polarographic surface PO2 electrode to assess testicular perfusion and viability following torsion and detorsion. Adult male Sprague-Dawley rats were divided into groups and subjected to unilateral testicular torsion and detorsion of varying degrees and durations. Rats subjected to sham torsion or 720 degrees torsion did not show significant decreases in testicular PO2 after 15 minutes, whereas those subjected to 1,080 degrees torsion or spermatic cord ligation uniformly decreased their testicular PO2 to 0 mm Hg within 10 minutes. Testicular PO2 values were similar in rats subjected to 60 minutes of 720 degrees torsion followed by detorsion and those undergoing 15 minutes of 1,080 degrees torsion and detorsion. Rats subjected to breathing 100% oxygen uniformly increased their testicular PO2 to an average of more than twice room-air values. However, rats subjected to 1,080 degrees torsion for 6 hours followed by detorsion did not increase their testicular PO2 when subjected to breathing 100% oxygen, whereas those subjected to 720 degrees torsion for 6 hours followed by detorsion did increase their testicular PO2 when subjected to breathing 100% oxygen. The latter rats did not show microscopic changes associated with acute testicular infarction, whereas the former did.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗