E. Converse Peirce

Embolization of left atrial myxoma after transseptal cardiac catheterization

Abstract Systemic embolization of an unsuspected left atrial myxoma during cardiac catheterization is described. Prompt histopathologic examination of the embolie specimen established the diagnosis, allowing the tumor to be successfully removed during cardiopulmonary bypass. The mechanism that led to the embolization and suggestions for avoidance of the complication are described.

Urinary Osmolal Changes in Renal Dysfunction Following Open-Heart Operations

Forty consecutive patients who underwent open-heart procedures using a hyperosmolar perfusion prime were studied to determine the significance of free-water clearance and urinary osmolality early after bypass in predicting the likelihood of postoperative renal dysfunction, defined as a blood urea nitrogen (BUN) level over 50 mg/100 ml. Urinary osmolality increased in all patients during the first 18 hours after bypass, but the increase was substantially less for those who subsequently developed renal dysfunction. Free-water clearance, which was significantly less negative in the patients with renal dysfunction by 2 hours after bypass and remained so throughout the 18 hours of this study, served as an early postoperative indicator of impaired renal function in the patients who eventually developed BUN elevation. Moreover, it was more sensitive as an index of renal dysfunction than was osmolality alone. Early recognition of renal impairment is important, as it may prevent dangerous fluid overloading and allow for corrective measures to be undertaken before frank renal failure develops.

A registry for carbon monoxide poisoning in New York City

In 1983 the North American Hyperbaric Center (affiliated with Bronx Municipal Hospital Center) was designated to provide Hyperbaric oxygen (HBO) for carbon monoxide (CO) patients meeting Emergency Medical System (EMS) criteria: 1. Unconscious or CNS derangement, any carboxyhemoglobin level [( COHb]); 2. [COHb] 25% or more; 3. Pregnant, any [COHb]. Through 1984, 39 CO patients received HBO; in 1985 81 were treated including 8 pregnant and 16 pediatric. CO sources were: fire, 43; heater, 21; engine, 17. 42 of 59 acute patients were initially in coma; 16 required CPR. Time to HBO averaged 4.5 hrs. Mean hospital [COHb] was 31% for acute, 28% for subacute/chronic, 15% for pregnant; mean maximum [COHb] was estimated: 51% for acute, 40% for subacute/chronic patients. Mean half life for [COHb] was 2.1 hrs. HBO typically was 46 min at 3ATA (2 [COHb] half lives), presented few problems, and gave rapid clinical improvement. 13 of 19 patients comatose before HBO were responsive after HBO (mean [COHb] was 1.8%). Four pediatric deaths occurred; brain damage was noted in two other patients. EMS efforts to make HBO available for CO is a success.

Clinical trials of a new polytetrafluoroethylene-silicone graft

A self-sealing polytetrafluoroethelene (PTFE)-silicone graft designed to be used early after implantation was placed in 30 end-stage renal disease patients. Thirty-five conventional PTFE grafts were used in the control group. All patients were followed for 1 year. In the PTFE-silicone graft group, median time for first use was 1 day after implantation. Conventional PTFE grafts were first used 2 to 4 weeks after implantation. Early punctures of the PTFE-silicone grafts (first 10 sessions), although more difficult to perform than late punctures, were not more difficult than punctures of conventional PTFE grafts. Late punctures in PTFE-silicone grafts were easier than conventional PTFE graft punctures. Bleeding after needle removal was significantly decreased after early and late punctures of PTFE-silicone grafts compared with conventional PTFE grafts (p less than 0.001). The PTFE-silicone graft can be used immediately after implantation, sparing patients additional access procedures for short-term dialysis. This results in less morbidity, decreased bleeding complications, shorter hospital stay, and a significant reduction in expenses.

Extracorporeal membrane oxygenation for massive pulmonary thromboembolism.

This study was undertaken to determine whether extracorporeal membrane oxygenation (ECMO) could modify the effects of massive lethal thromboembolism and prevent death. Twenty anesthetized dogs were prepared for venoarterial perfusion with a demand pump and membrane lung and were perfused slowly for 1 1/2 hours to lessen homologous blood shock; 1 ml per kilogram of 24-hour-old tantalum-impregnated thrombus was injected intravenously. The dogs had profound systemic hypotension with an elevated mean pulmonary artery pressure (62.9 +/-4.5 mm Hg) immediately after embolization. Control animals generally died within 15 minutes. Four of the 10 ECMO-supported animals lived for six days, at which time they were restudied and killed. Not only can ECMO maintain an animal that would otherwise die quickly of massive pulmonary thromboembolism, but such support, even though temporary, can greatly improve the chances of survival.

A self-sealing dialysis prosthesis. Coaxial double PTFE-silicone graft.

The performance of a new dialysis prosthesis designed to self-seal after puncture was tested ex vivo and in vivo. It consists of two coaxial polytetrafluoroethylene tubes (PTFE), the space between them filled with silicone rubber sealant (PTFE-sil). Ex vivo: Three PTFE-sil, three double PTFE (without silicone), and three single PTFE grafts were placed sequentially between scribner shunts in the hind limb of four dogs. Bleeding on puncturing with an 18-gauge needle was measured for 30 seconds. PTFE-sil bled less than the controls (g): PTFE-sil; 16 +/- 18; double PTFE: 32 +/- 10; single PTFE: 52 +/- 19 (p less than 0.001). In vivo: Six PTFE-sil and five single PTFE grafts were interposed between the carotid artery and jugular vein of dogs and were punctured with a 16-gauge needle on days 1, 3, and 7. Bleeding was measured through an incision over the puncture site at 5 minutes. In 11 punctures of PTFE-sil, there was no bleeding; three bled less than 20 g. In 13 control punctures, none bled less than 70 g. Patency: Grafts were studied for patency in arteriovenous (AV) fistulas in 34 dogs. Each dog received a PTFE-sil graft in one groin and a single PTFE control graft in the other. At 4 months, patency rates were: PTFE-sil, 84%; single PTFE, 87% (NS). Four months after implantation, hemostasis after puncture in PTFE-sil grafts required 70 +/- 49 seconds versus 207 +/- 48 seconds for PTFE grafts (p less than 0.005). In conclusion, PTFE-sil grafts are self-sealing, can be used immediately after implantation, and need minimal compression after needle removal.

Recent changes in criteria for selecting the level of amputation of the leg.

demonstration that the pretibial skin consistently has a lower blood pressure than the calf skin helps to explain this important clinical observation.’ Because present-day prostheses do not require specific placement of the scar, the short anterior flap causes no difficulty in the wearing of a prosthesis. However it has been recognized that in spite of healing of the skin, necrosis of the underlying muscle may necessitate subsequent above-knee amputation. To avoid this problem, it has been the practice of most surgeons to incise the skin and muscle and to make a final determi-