Document yk1D7yeqjmve59Qw749LgDonD

If Anesthesiology V 4. No 6. Jun 197b CLINICAL REPORTS 445 =,. Rudin DO. Fremont-Smith K. Beecher HK: Permeabilitv of dura mater to epidural procaine in dogs. J Appl Physiol 3:388-398. 1951 16. Bromage PR: Mechanism of action of extradural analgesia. BrJ Anacsth 47:199-212. 1975 17. Dogliotti AM: Anesthesia. Chicago. S. B. DeBour. 1939. pp 499-625 18. Kamsler PM. Dabbs CH. Southworth JL: Regional spinal anesthesia. Anesthesiology 13:397-406, 1952 19. Saltlad M, Dwyer CS. Kronenberg S. et al: Intraspinal seg mental anesthesia: A preliminary report. Anesthesiolocy 8:270-287. 1947 20. Greene NM: Physiology of Spinal Anesthesia. Baltimore. Williams and Wilkins, 1969, p 18 21. Bromage PR: Lower limb reflex changes in segmental epidural analgesia. BrJ Anaesth 46:504-508. 1974 Anesthesiology 48:445-447, 1978 NOTICE This muteiial may be protected by copyright law (Title 17 U.S. Code). Thrombogenesis Associated with Swan-Ganz Catheters Paul F. Hoar, Ph.D., M.D.,* J. Gilbert Stone, M.D.,* Anthony E. Wicks, M.D.,* Richard N. Edie, M.D.,t John V. Scholes, M.D4 With the technical assistance of Michael B. Mirsky, M.S. The balloon-tipped, flow-directed, flexible pul monary-artery (Swan-Ganz) catheter has gained clini cal acceptance and increased usage since its introduc tion in 19701 Occasional complications have been reported to occur with the use of this indwelling device.2 *Pul monary infarction related to thrombus formation in two patients has beert reported. In another report, a massive thrombus extending from the tip of a SwanJanz catheter and obstructing the main pulmonary artery was stated to be a contributory if not the pri mary cause of death in a patient on the basis of post- ortem examination.4 Although thrombus adherent to the catheter has en occasionally observed,1,4 a systematic evaluation f this phenomenon has not been undertaken. Cardiac urgery affords a unique opportunity to examine wan-Ganz catheters in situ when the right atrium is pened to establish cardiopulmonary bypass. This re tort relates our observations of thrombus formation i Swan-Ganz catheters placed immediately prior to duction of anesthesia and examined at operation. Methods Swan-Ganz catheters were consecutively placed and amined in ten patients undergoing cardiac surgery. 1 Assistant Professor of Anesthesiology, t Assistant Professor of Surgery. J Chief Resident, Department of Pathology. ( Technical Director, Department of Anesthesiology. Received from the Departments of Anesthesiology, Surgery d Pathology, College of Physicians and Surgeons of Columbia niversity. 630 West 168th Street, New York. New York 10032. 'cepted for publication December IS, 1977. Supported in part by IH Grant GM-09069. Address reprint requests to Dr. Hoar. The catheters were inserted immediately prior to in duction of anesthesia and inspected at the time of cardiopulmonary bypass. The catheters were placed percutaneously via the internal jugular vein. After intravenous cannulation.H a flexible steel guide wire** was inserted through the cannula, the cannulla removed and an obturator and introducertt were threaded over the guide wire into the internaljugular vein. Upon removal of the guide wire and obturator, the introducer was flushed with 10 ml heparinized saline solution (1,000 units of heparin in 500 ml saline solution) and a 7F Swan-Ganz thermodilutioii pulmonary-artery catheter,$$ also flushed and filled with 5 ml heparinized saline solution, was immediately placed through the introducer. The catheter was ad vanced to 20 cm, the balloon inflated, and the catheter floated into the most proximally achieved wedge posi tion in the pulmonary artery during constant electro cardiographic and artery pressure monitoring. Fol lowing establishment of the wedge posiuon, the catheter balloon was deflated to ensure that the SwanGanz catheter was not in a permanent wedge posidon. The appearance of a phasic pulmonary artery pres sure tracing after balloon deflation provided confirmadon of the catheter's posidon. The catheter balloon was only intermittently inflated when wedge pressures were recorded. Prior to inducuon of anes thesia, a hemodynamic profile that included heart rate 5 Argyle Medicut cannula, Sherwood Medical Industries, St. Louis, Missouri. ** 0.032' flexible guide wire (6 inch). Universal Medical Instrument Corp., Ballston Spa, New York. tt #8F Percutaneous catheter introducer, Universal Medical Instrument Corp.. Ballston Spa. New York. Swan-Ganz flow-directed triple-lumen thermodilution cathe ter 9SA-I18-7F. Edwards Laboratories. Santa Ana. California. 0003-3022/78/0600--0445300.60 C The American Society of Anesthesiologists, Inc. 21989001 BFG17429 446 CLINICAL REPORTS Anestbd.i^ V 48. No6.J,,rSjJ Fic. I. Thrombus removed from a Swan-Ganz catheter during cardiopulmonary bypass. Thrombus encapsulated the catheter surface extending from the tip retrograde along the shaft. and rhythm, systemic arterial pressure, pulmonary arterial wedge pressure, and cardiac index was ob tained. The pressures were measured by transducers; cardiac outputs were determined by thermal dilution technique, and all values recorded on a thermal tip chart recorder. Anesthesia was induced with combinations of mor phine sulfate (0.5-1.5 mg/kg), diazepam (5-20 mg), and nitrous oxide (50-70 per cent). Muscle relaxa tion was facilitated with d-tubocurarine (2 mg/kg) and respiration controlled to maintain Pco2 35-40 torr. The chest was opened through a median sternotomy and heparin (90 mg/m*) administered to all patients 15 minutes prior to bypass. Atriotomy allowed temporary displacement of the Swan-Ganz catheter from the pulmonary artery and right ventricle, and inspection from the tip retrograde to the level of the right atrium. Results Ten Swan-Ganz catheters were consecutively ex amined in seven men and three women at the time of cardiopulmonary bypass. Nine patients were to undergo coronary-artery surgery and one patient was to have both aortic and mitral valves replaced. The hemodynamic profile of the patients is shown in table 1. Five of the patients had cardiac indices below 2.5 l/min/mJ. but the remaining five had an aver age cardiac index of 3.10 l/min/m:. Two patients were in atrial fibrillation and one had an elevated wedge pressure (25 torr). No patient was hypo tensive. and all other hemodynamic variables were within normal limits. Everv patient had a normal pre operative coagulation screen, consisting of pro thrombin time, activated partial thromboplastin time, and platelet count. The mean time from introduction of the catheter to final positioning was less than 2 min. The cathetert were inspected 104 6 (SE) min following insertion (table 2). Thrombus was found on the surfaces of all catheters examined at surgery. The thrombi encapsulated the cathetefs, extending from the tip along the shaft (fig. 1). Thrombi removed from the catheters at operation had a mean length of 7.8 i 1.2 (SE) cm and a mean weight of 222 46.8 mg (table 2). The largest weighed 570 mg. Histologic examination of all removed thrombi demonstrated recent thrombus formation with lysis of erythrocytes, layering of leuko cytes (forming lines of Zahn) and fibrin deposition. There was no statistical correlation between thrombus size and the hemodynamic status of the patient, the duration of catheter insertion, or the time to catheter inspection. Discussion That thrombus formation occurs when any intra vascular catheter is placed is not new information. Thrombi have been found on both indwelling arterial and central venous catheters.*-7 Massive thrombus formation secondary to Swan-Ganz catheterization was found post mortem in a patient who had had a catheter in place for a prolonged period before dying.4 In our series, however, the Swan-Ganz catheters were inserted one to two hours prior to inspection, yet substantial clots were seen along the catheter in all instances. Factors that may contribute to thrombus formation on Swan-Ganz catheters must be considered. As part of Table 1. Hemodynamic Profile of Ten Patients Undergoing Cardiac Surgery in Whom Swan-Ganz Catheters Were Placed Prior to Anesthetic Induction Age (Yean) Heart Race (Beati/Min) Mean Systemic Anerial hesiure <U*T) Cardiac Index (l/min/m*) Pulmonary Arterial Wedge Pressure (torr) Central Venom (tOTT) Mean 61 64 84 2.5 SE * 1.7 5 4 * 0.3 Range 58-70 44-102 70-115 1.79-2.91 7.4 2.4 0-25 3.2 0.9 0-7 Table 2. Details of Catheter Insertion and Thrombus Formation for Swan-Ganz Catheters Placed Prior to Anesthetic Induction in Ten Patients Undergoing Cardiac Surgery Mean SE Range Insertion Time (Min) 1.9 i .15 0.9-2.7 Time from insertion l<> Inspection (Mini 104 -6 60-130 Thrombus Length icmi 7.8 a 1.2 3.0-17.0 Thrombus Wnghi img* 222 2 46.8 55-570 21989002 BFG17430 An*Mh-uoJofcv V 4. No H. Jun I'.'TH CLINICAL REPORTS 447 the preoperative evaluation, every patient had a coagulation screen, which was normal in each case. The introducers and catheters were flushed and filled with heparinized saline solution prior to placement in the internal jugular vein. All catheters were rapidly "floated" into the pulmonary artery by the flowdirected technique, and no catheter was left in a permanent wedge position. Although catheters were not all placed with the same rapidity, thrombi were found at operation when the total placement time was less than a minute. The largest thrombus was seen in a patient who was in atrial fibrillation with evidence of congestive heart failure. Yet the second largest thrombus was found in a patient with no evidence of a low-output state. It may be that a low-flow state enhances thrombus accumulation, but this study did not yield evidence to support such a correlation. In any event, patients with impaired hemodynamics are the patients who most need SwanGanz catheters for management. Sawyer et al* have evaluated the thrombogenic characteristics of commercially available catheters and have found them all to induce thrombus formation within hours of implantation in the central venous circulations of dogs and man. The Swan-Ganz catheter was not evaluated by Sawyer et al., but is constructed of polyvinylchloride, which does initiate a thrombo genic response. Heparin in low doses (40 units/kg) has been ad ministered systemically to help prevent thrombo embolic complications during angiography.* How ever, our preliminary studies have demonstrated that preinsertion administration of such low-dose heparin to patients prior to Swan-Ganz catheterization does not prevent thrombus formation on these devices, although thrombus size may be reduced. Conclusions drawn from this study are: 1) The thermodilution flow-directed Swan-Ganz catheter in duces thrombus formation in the central circulation of a patient with either normal or impaired cardio vascular hemodynamics. 2) Thrombus formation [probably begins at the time of insertion and can be demonstrated an hour following placement. 3) Thrombus formation occurs despite the precautions of filling the introducer and catheter with heparinized saline solution before introduction, rapid placement of the catheter in the pulmonary artery, and not Allowing the device to assume a permanent wedge position. Despite these observations, no evidence of massive pulmonary embolism (symptomatic or radiologic) has sen seen in any of our patients, although several hundred Swan-Ganz catheters have been inserted with the same technique. It is probable that the thrombi formed did release emboli, but signs and symptoms of small emboli may be clinically inap- parent in the postoperative period following cardiac surgery. It is not the intent of this report to dissuade physi cians from placing Swan-Ganz catheters in patients who may benefit from the information provided. In any medical setting, where the management of hemodynamic dysfunction requires intense monitor ing, the cost-benefit ratio seems to favor the use of Swan-Ganz catheters. It is the intent of this report, however, to call attention to the potential thrombogenicity of these devices. If other invesugators con firm our consistent finding of thrombus adherent to all Swan-Ganz catheters following placement, it may be helpful to treat the catheter surface chemically in order to render it less thrombogenic.10,u However, the effects of such treatment on the structural ma terial may affect the flexibility of the device, alter ing the physician's ability to position catheters rapidly in the pulmonary artery.Hf The authors thank Mr. E. Kahn for his help in this study. References 1. Swan HJC, Ganz W, Forrester JS, et al: Catheterization of the heart in man with the use of a flow-directed bal loon tipped catheter. N Engl J Med 283:447-451, 1970 2. Buchbinder N. Ganz YV: Hemodynamic monitoring. Anesthesiology 45:146-155, 1976 3. Foote GA, Schabel SI. Hodges M: Pulmonary complications of the flow-directed balloon tipped catheter. N Engl J Med 190:927-931, 1974 4. Yorra FH, Oblath R. Jaffe H, et al: Massive thrombosis asso ciated with use of the Swan-Ganz catheter. Chest 65: 682-685, 1974 5. McDonough JJ, Altemeier WA: Subclavian venous thrombosis secondary to indwelling catheters. Surg Gynecol Obstet 133:397-400, 1972 6. Walters MB, Stanger HAD, Rotem CE: Complications with percutaneous central venous catheters. JAMA 220:14551457, 1972 7. Downs JB, Racksiein AD, Klein EF. et al: Hazards of radial artery catheterization. Anesthesiology 38:283-286, 1973 8. Sawyer PN. Stanczcwski B, Garcia L, et al: Experimental and clinical evaluation of a new catheter material. Trans Am Soc Artif Intern Organs 23:527-537, 1976 9. Walker WJ, Mundall SL. Broderick HG, et al: Systemic heparinization for femoral percutaneous coronary arteriog raphy. N Engl J Med 288:826-828, 1973 10. Nishizawa EE. Wynalda DJ, Lednicer D: Non-thrombogenic surface-inhibiting platelet adherence. Trans Am Soc Anil Intern Organs 19:13-18, 1973 11. Lindsay RM. Rourke J. Reid B, et al: Platelets, foreign sur faces and heparin. Trans Am Soc Artif Intern Organs 22: 292-295, 1976 5 Personal communication. Edwards Laboratories, Santa Ana, California. Personal communication, Battelle Laboratories, Columbus. Ohio. 21989003 BFG17431 m mu*