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Biomedical subjects

W D Spotnitz

Publications and source records attributed to W D Spotnitz.

At least 73 records · Page 4Linked to original sources

Four years' experience with fibrin sealant in thoracic and cardiovascular surgery.

A single-donor fibrin sealant system was used in 689 thoracic and cardiovascular surgical procedures over the 4-year period between April 1, 1985, and March 31, 1989. An excellent overall success rate (646/689, 94% effective) was achieved with specific applications, including reduction of leakage of air (29/33, 88% effective), blood (595/634, 94% effective), and fluid (14/14, 100% effective), as well as positioning of anatomical structures such as coronary bypass grafts (8/8, 100% effective). Application methods included use of spray bottles (477/497, 96% effective), syringes (165/186, 89% effective), and a Silastic cannula through the flexible fiber-optic bronchoscope (4/6, 67% effective). The system was used in a wide variety of cardiac, pulmonary, esophageal, and vascular procedures to seal staple lines, suture lines, anastomoses, conduits, fistulas, and raw surfaces. No complications with this single-donor system secondary to blood-borne disease have been documented. Overall infection occurred at a nominal rate (16/689, 2%). Thus, fibrin sealant has been a useful tool to control the leakage of air, blood, and fluid during a wide variety of thoracic and cardiovascular procedures and may be of benefit to other surgeons.

Aerosols↗

Intraoperative assessment of regional myocardial perfusion using quantitative myocardial contrast echocardiography: an experimental evaluation.

To test the hypothesis that myocardial contrast echocardiography can be used to quantitate regional myocardial flow in the arrested heart at the time of delivery of cardioplegic solution, data were acquired in 13 dogs on cardiopulmonary bypass. Different degrees of stenosis were placed in random order on the left anterior descending coronary artery. For each stenosis, myocardial contrast echocardiography was performed by injecting sonicated albumin microbubbles into the cross-clamped aortic root at the time of delivery of cardioplegic solution. The resultant echocardiographic images were analyzed on an off-line computer. Background-subtracted time-intensity plots were generated, and an exponential function, f(t) = Ce-alpha t + De- beta t, was applied to each plot. Variables that reflected the total number of microbubbles entering the coronary artery bed, such as the area under the curve and the peak height of the curve, correlated best with radiolabeled microsphere-measured myocardial flow (r = 0.92 and r = 0.91, respectively). Variables that reflected the appearance of contrast microbubbles in the myocardium, such as the initial slope and the slope at 1 s, also had a good correlation with myocardial flow (r = 0.84 and r = 0.89, respectively). Variables that reflected the washout of contrast medium from the myocardium, such as the slope of the descending portion of the curve, had only a fair correlation with myocardial flow (r = 0.65). In six dogs, the technique of injecting contrast medium into the cross-clamped aortic root was also examined. Although continuous infusion of contrast medium produced smaller perturbations in mean aortic and distal left anterior descending artery pressures compared with a bolus injection (p less than 0.01), the correlation between the variables of the time-intensity curves and flow was equally close with both techniques. It is concluded that it is possible to quantitate myocardial flow by using myocardial contrast echocardiography at the time of delivery of cardioplegic solution in dogs on cardiopulmonary bypass. The implementation of this technique in humans might be useful in guiding the sequence of graft placement and thereby improving myocardial preservation during coronary artery bypass operations.

Animals↗

Intraoperative assessment of myocardial perfusion using contrast echocardiography.

Myocardial contrast echocardiography is a new technique capable of assessing regional myocardial perfusion in vivo in real time. This article reviews the background, principles, experimental validation, and clinical uses of intraoperative myocardial contrast echocardiography. Data can be derived both for online visual and computer analyses. The technique can be useful in determining the sequence of bypass graft placement and the success of graft anastamoses. Anastamoses can be revised immediately if needed. It is hoped that this technique will improve intraoperative myocardial preservation and will diminish the rate of perioperative myocardial infarction.

Cardioplegic Solutions↗

Hemodynamic effects of rapid vancomycin infusion in critically ill patients.

The rapid infusion of vancomycin produces histamine release resulting in rash ("red-man's" syndrome) and hypotension. Because this phenomenon has been described primarily in healthy subjects, we prospectively studied the rapid infusion of vancomycin in 16 critically ill patients after open heart surgery in an attempt to document histamine release with resulting hemodynamic changes, and to see if there is any correlation with vancomycin levels. After establishing baseline hemodynamic stability and histamine levels, 1 g vancomycin diluted in 50 mL of 5% dextrose was infused over 30 min. Cardiac index, heart rate, blood pressure, pulmonary venous pressures, and systemic and pulmonary vascular resistances remained unchanged during the infusion. Although the mean plasma vancomycin level increased to a peak of 69 +/- 20 micrograms/mL after 20 min of the infusion before declining, mean plasma histamine levels in 15 of the 16 patients remained within the normal range during the infusion. In one patient a baseline histamine level (2.8 ng/mL) more than three times the normal before the vancomycin infusion increased further during the infusion (3.0, 4.9, and 5.0 ng/mL at t = 10, 20, and 30 min, respectively), and remained elevated (2.9 ng/mL) 30 min after the infusion. This patient developed the red-man's syndrome, although there were no hemodynamic changes. There was no evidence of myocardial depression in any of the patients. In conclusion, we safely infused a concentrated solution of vancomycin into critically ill patients over 30 min without any adverse hemodynamic changes. One patient developed the red-man's syndrome. There was no correlation between peak vancomycin levels and the release of histamine in this patient population.

Adult↗

Neurosurgical applications of fibrin glue: augmentation of dural closure in 134 patients.

In a wide variety of neurosurgical procedures performed on 134 patients over a 3-year period, fibrin glue has been applied as an adjunct to dural closure. Overall success at preventing cerebrospinal fluid (CSF) leakage was 90% (121 of 134, 90% effective). In patients considered to be at high risk for CSF leakage intraoperatively but without pre-established fistulae (Group 1), the success rate was higher (111 of 119, 93% effective). In patients with pre-established CSF fistulae (Group 2), the success rate was lower (10 of 15, 67% effective). As single donor sources of concentrated fibrinogen are now available with reduced risks of blood-borne disease transmission, fibrin glue may be a valuable clinical tool for the neurosurgeon.

Dura Mater↗

Pepsin fibrinolysis of artificial clots made from fibrinogen concentrate and bovine thrombin: the effect of pH and epsilon aminocaproic acid.

Artificial clots made from fibrin glue with and without an inhibitor of fibrinolysis can be used to treat gastrointestinal bleeding. We have been unable to find descriptions of the effects of acid and pepsin upon such artificial clots. Therefore, 10(-2) mol/l epsilon aminocaproic acid was added to fibrin glue in vitro at acid concentrations of pH 1.0 and pH 5.5. Pepsin was added at 9000 U/50 ml, the expected value for fasting human subjects. There was a highly significant reduction in clot survival at pH 1.0. At pH 5.5, clot weight was also significantly decreased with pepsin, compared to control. Thus pepsin and acidity greatly affect survival of artificial clots, but the addition of epsilon aminocaproic acid did not affect clot survival.

Aminocaproates↗

Mediastinal fibrin glue: hemostatic effect and tissue response in calves.

There is continued controversy regarding the effectiveness and potential adverse effects of fibrin glue. Thus, we chose to evaluate it in a model of experimental calf aortic valve replacement that has been previously well established. Concentrated fibrinogen and topical thrombin were sprayed to form a thin layer of fibrin glue over the mediastinal tissues of 20 consecutive calves undergoing aortic valve replacement. Chest tube outputs of these animals were compared with those of the preceding 20 consecutive calves undergoing aortic valve replacement without fibrin glue. All procedures were performed by the same surgeon, and no other technical changes were made between the two series. Total postoperative chest tube output (mean +/- standard error) was 553 +/- 50 mL for the calves treated with fibrin glue and 1,155 +/- 103 mL for the control calves (p less than 0.001). On histological examination of mediastinal tissues from 5 treated calves killed 6 weeks after operation, there was no evidence of inflammation, fibrosis, or residual fibrin. To our knowledge, this is the first controlled laboratory study to show that fibrin glue spray is an effective hemostatic agent and that it produces no long-term tissue reaction.

Animals↗

Laparoscopically applied fibrin glue in experimental liver trauma.

We have investigated the feasibility of applying fibrin glue to liver injuries using laparoscopic guidance and have examined the gross and microscopic changes that occurred in hepatic lacerations treated with fibrin glue. These studies indicate that fibrin glue may be effectively applied to liver injuries using laparoscopic control, hepatic bleeding may be rapidly controlled when fibrin glue is applied into the base of the wound, there is no gross or microscopic evidence of hepatic toxicity related to the use of fibrin glue, and healing of liver lacerations treated by fibrin glue occurs by ingrowth of granulation tissue coupled with fibrinolysis of the fibrin glue.

Animals↗

Successful use of fibrin glue during 2 years of surgery at a university medical center.

A method for producing concentrated fibrinogen, an essential component of fibrin glue, from individually stored, single-donor units of human plasma is reported. The plasma is screened for hepatitis B antigen and HIV-1 virus to reduce the risk of transmission of hepatitis and acquired immunodeficiency syndrome (AIDS). This material is routinely stocked in some operating rooms. It is thus readily available when requested by a surgeon for use in combination with topical bovine thrombin to produce fibrin glue. From April 1985 to March 1987 this material was used by surgeons from eight different surgical specialties on 413 patients with a 91 per cent success rate (376/413). Uses have included sealing vascular suture lines, reinforcing pulmonary and esophageal staple lines, closing dural cerebrospinal fluid leaks, fixing split-thickness skin grafts, reducing lymphatic leakage, and controlling bone bleeding. Additional uses include closure of bronchopleural fistulas by means of the flexible bronchoscope, reduction of perioperative hemorrhage by spraying fibrin glue on the anterior mediastinum during cardiac surgery, and reduction of bleeding during debridement of burn eschars. Careful monitoring and patient follow-up detected no cases of transmission of blood-borne diseases. Only one complication, a local wound infection, has been documented. This material has been an important adjunct for the surgical services and may be safely used at hospitals with local blood bank facilities.

Aprotinin↗

Pericardial cyst. A rare mass abutting the aorta.

Pericardial cysts are infrequently found. They are generally located in the cardiophrenic angle, dominantly on the right side. We present an example of a pericardial cyst in the anterior mediastinum abutting the ascending aorta.

Aged↗

The reversal of amiodarone-induced perioperative reduction in cardiac systolic reserve in dogs.

There is controversy about the myocardial depressant effects of amiodarone in patients with decreased cardiac function undergoing surgery. Some surgeons believe that these effects complicate the discontinuation of cardiopulmonary bypass. Accordingly, the hemodynamic effects of amiodarone were evaluated in two groups of anesthetized mongrel dogs that had undergone a median sternotomy. A control group of 10 dogs and an amiodarone-treated group (15 mg/kg per day for 3 weeks) of 10 dogs were studied, and serum (0.26 to 1.09 micrograms/ml) and tissue (cardiac 2.97 to 11.60 micrograms/ml) levels of amiodarone were measured by liquid chromatography. Hemodynamic measurements were made at baseline and after administration of routine therapeutic intravenous doses of dobutamine (10 micrograms/kg per min), isoproterenol (0.06 micrograms/kg per min) and epinephrine (2 micrograms/min). The amiodarone-treated dogs had a smaller increase in cardiac output compared with baseline than did control dogs. For each drug when the amiodarone-treated group was compared with the control group, increases in cardiac output (liters/min) were: dobutamine, 1.32 +/- 0.24 versus 1.73 +/- 0.31; isoproterenol, 0.84 +/- 0.26 versus 1.43 +/- 0.28; epinephrine, 0.25 +/- 0.15 versus 0.44 +/- 0.53. Amiodarone-treated dogs were also given higher doses of drugs, dobutamine (50 micrograms/kg per min), isoproterenol (1.2 micrograms/kg per min) and epinephrine (20 micrograms/min). Increases in cardiac output were 1.24 +/- 0.24, 1.62 +/- 0.25 and 2.82 +/- 0.64, respectively. All cardiac outputs were significantly increased from the baseline values (p less than 0.05) except those measured in the amiodarone group receiving the lower dose of epinephrine. Thus, amiodarone-treated dogs have a relative reduction of perioperative cardiac systolic reserve.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiodarone↗

Success of internal mammary bypass grafting can be assessed intraoperatively using myocardial contrast echocardiography.

To determine whether the success of internal mammary artery bypass grafting can be assessed intraoperatively using myocardial contrast echocardiography, sonicated Renografin-76 was injected into the aortic root of 11 dogs during the delivery of cardioplegic solution. Studies were performed with the left anterior descending coronary artery patent and totally occluded, and after internal mammary artery bypass grafting distal to the occluded vessel. Flow rate during cardioplegia was constant for all three stages in each experiment. Myocardial contrast echocardiography clearly demonstrated homogeneous myocardial perfusion with the left anterior descending coronary artery patent, lack of perfusion in the left anterior descending artery bed during its occlusion and excellent perfusion of the occluded bed after internal mammary artery bypass grafting distal to the occlusion in 10 of the 11 dogs. In one dog, the bypass graft was technically inadequate and contrast opacification was not noted in the left anterior descending artery bed after internal mammary artery bypass grafting. The exponential function C(t) = Ae-alpha t + Be-beta t was fitted to computer-derived time-intensity curves from the myocardium, where alpha denotes contrast washout and beta denotes contrast appearance. Respective values for alpha and beta (mean + 1 SD) were similar for the patent left anterior descending coronary artery and after internal mammary artery bypass grafting distal to the occluded artery (0.11 +/- 0.10 versus 0.10 +/- 0.10, and 2.5 +/- 2.4 versus 1.1 +/- 0.56). In conclusion, myocardial contrast echocardiography has potential for intraoperative assessment of the adequacy of coronary artery bypass grafting.

Animals↗

Seroma prevention using fibrin glue during modified radical neck dissection in a rat model.

Seroma is a frequent sequelae of neck dissection involving cervical lymphadenectomy. The incidence is correlated with flap elevation, lymphovascular interruption, and tissue removal. Current methods of resolving seroma, such as vacuum drainage, are not risk free. A novel approach to this problem was the use of intraoperative topical fibrin glue. A model producing seromas was developed by modified radical neck dissection on Sprague-Dawley rats. Forty rats underwent this procedure. Twenty rats were treated with saline solution (control group) and 20 were treated with fibrin glue. At necropsy on day 5, a significant reduction in the frequency of seroma was noted in the fibrin glue group. Seventeen of 20 control rats had seroma whereas only 2 of 20 experimental animals had serous collection. The Fisher exact statistical correlation revealed p less than 0.000002; therefore, the use of fibrin glue in this role merits further evaluation.

Animals↗

Reconstruction of full thickness chest wall defects.

Over the last 5 years, 14 patients were treated by wide en bloc resection of chest wall tumors with primary reconstruction. There were nine females and five male patients with an age range of 31-77 years. All patients had a skeletal resection of the chest wall. An average of 3.9 ribs were resected in the patients treated. In three patients a partial sternectomy was carried out in conjunction with the rib resections. Chest wall skeletal defects were reconstructed with Prolene mesh, which was placed under tension. Soft tissue reconstruction utilized selected portions of the latissimus dorsi musculocutaneous territory with fasciocutaneous extensions beyond the muscle itself. Primary healing was obtained in all patients and secondary procedures were not required. The average hospitalization was 23 days. All patients survived the resection and reconstruction and were alive 30 days after operation. In selected patients the preservation of a portion of the innervated muscle in situ or the transfer of the muscle with the preservation of its resting length has maintained the majority of the muscle function.

Adult↗

Reduction of perioperative hemorrhage by anterior mediastinal spray application of fibrin glue during cardiac operations.

A variety of published techniques for the production of concentrated fibrinogen from units of screened single-donor human plasma have led to increasing clinical use of fibrin glue in the United States. We have adapted a method of applying this material with a disposable plastic sprayer. In 20 consecutively treated patients, fibrin glue was sprayed on the anterior mediastinum before closure of the median sternotomy incision. A control group of 20 patients undergoing the identical cardiac operations (13 coronary artery bypass grafting procedures [CABG], 4 valve replacements [including 1 reoperative procedure], and 3 combined valve replacements and CABG) by the same surgeon within a one-year period was chosen for comparison of chest tube outputs. Specifically, chest tube outputs were as follows for treated and untreated patients, respectively: at 12 hours, 461 +/- 40 ml (mean +/- 1 standard error of the mean versus 731 +/- 80 ml; at 24 hours, 714 +/- 73 ml versus 1,016 +/- 109 ml; and at 48 hours, 863 +/- 93 ml versus 1,187 +/- 137 ml. The differences between control and spray chest tube output are statistically significant by unpaired t test (p less than 0.05) at both 12 and 24 hours. Thus, this method can reduce perioperative hemorrhage from the anterior mediastinum after cardiac operations.

Aerosols↗

Fibrin glue from stored human plasma. An inexpensive and efficient method for local blood bank preparation.

European surgeons have used fibrin glue extensively during thoracic, cardiovascular, and general surgical operations. Until now, however, it has been available only as a commercial preparation made from pooled human plasma, and it has not been approved by the U.S. Food and Drug Administration for use in the United States because of a high associated risk of hepatitis and acquired immune deficiency syndrome. Methods of obtaining fibrinogen, an essential component of fibrin glue, from cryoprecipitate or fresh frozen plasma have been published recently. However, the cryoprecipitate method results in relatively low concentrations of fibrinogen, which can reduce glue effectiveness. The fresh frozen plasma method is more expensive and does not meet the standards of the American Association of Blood Banks for the "closed" system required for safe handling and management of blood component products. Both the cryoprecipitate and the fresh frozen plasma methods result in waste of unstable clotting factors. These factors are necessary to replace human plasma clotting deficiencies but are not necessary for the production of fibrin glue. The authors have developed an efficient, high-concentration blood bank method for producing and maintaining a local supply of a safer and less expensive but equally effective material derived from stored human plasma. This material is produced using approved blood bank techniques for a "closed" system in blood component production, thus reducing the risks of contamination and infection, and its fibrinogen concentration is higher than that of standard cryoprecipitate. The cost of 1 unit of this fibrin glue is comparable to that for 1 unit of cryoprecipitate and less than that for 1 unit of fresh frozen plasma.(ABSTRACT TRUNCATED AT 250 WORDS)

Aprotinin↗