Infusion rates and levels of premedication in tumescent liposuction.

BACKGROUND: Tumescent liposuction has proven to be an extremely safe and effective method of liposuction. However, the infusion of tumescent anesthesia can take 1 hour or more to complete. OBJECTIVE: To document the types, dosages, and routes of administration of premedication utilized by four experienced tumescent liposuction surgeons. To determine if infusion rates for tumescent anesthesia are affected by types of premedication. METHODS: Four experienced liposuction surgeons were asked to review their most recent 100 tumescent liposuction patients with respect to types and dosages of premedication and routes of administration. Data were also provided on corresponding infusion pump settings and infusion rates. Volumes of tumescent anesthesia and corresponding volumes of fat aspirated were also collected on the same 400 patients. RESULTS: Infusion of tumescent anesthesia could be performed more rapidly in patients who were given greater amounts of premedication. Volumes of tumescent anesthesia infused were generally two or more times the volume of fat aspirated. Patients could be infused with less premedication if slow infiltration was employed. CONCLUSION: Infusion rates for tumescent anesthesia can be increased of greater amounts of premedication are given. However, this must be balanced against the safety of the premedication.

Characterization of a tubular flow chamber for studying platelet interaction with biologic and prosthetic materials: deposition of indium 111-labeled platelets on collagen, subendothelium, and expanded polytetrafluoroethylene.

A plastic (Plexiglas) chamber for evaluating platelet deposition under controlled hemodynamic conditions has been developed. The perfusion chamber has been designed to retain the cylindrical shape typical of the vasculature, to be flexible enough to accept a variety of biologic and prosthetic materials, and to simulate a broad range of physiologic flow conditions in either an ex vivo or in vitro perfusion system. Three type of surfaces were exposed to blood flowing directly from the carotid artery of a heparinized pig through the perfusion chamber: de-endothelialized pig aorta, collagen strips from rabbit Achilles tendon, and an expanded polytetrafluoroethylene material (Gore-Tex). Platelets, previously radiolabeled with indium 111 and injected into the animal, were quantified on the material surface, and the total number of deposited platelets determined for a range of blood flow rates (5 to 40 ml/min) and exposure times (0.5 to 20 minutes). The deposition rates were correlated with theory for describing the mass transport of platelets to the test surface. At the wall shear rates investigated (105 to 850 sec-1), the deposition of platelets on subendothelium was strongly dependent on the local flow conditions. Values of deposition on Gore-Tex obtained at similar flow conditions (105 to 425 sec-1) were reduced compared with that observed on subendothelium and showed a markedly weaker dependence on the shear rate. In contrast, deposition of platelets on collagen was more than an order of magnitude greater than on subendothelium and showed a dependence on flow only at the lowest flow rate studied (10 ml/min). The results indicate that collagen is much more reactive than subendothelium and Gore-Tex with respect to the growth and stability of platelet aggregates and moreover suggest that flow mechanisms for depositing platelets on various surface may be substantially different.

Spontaneous and diet-induced coronary atherosclerosis in normal swine and swine with von Willebrand disease.

We have observed that pigs with impaired platelet function in the form of severe von Willebrand's disease (vWd) are resistant to spontaneous and to diet-induced aortic atherosclerosis. However, it has been reported that vWd pigs are susceptible to coronary atherosclerosis produced by balloon-induced injury of coronary arteries combined with an atherogenic diet. We have evaluated the development of coronary atherosclerosis in normal control (NC) and homozygous vWd pigs in two prospective studies: 1) as a spontaneous process in five NC and vWd pigs receiving a regular diet from the age of 3 months to 4 years; and 2) in nine NC and five vWd receiving a high-fat and high-cholesterol (2%) diet from the age of 3 to 9 months. All of the coronary arteries were analyzed postmortem in 5-mm sections. None of the NC nor the vWd pigs in the spontaneous study showed coronary atherosclerosis or myocardial lesions. In the study of diet-induced atherosclerosis, only one NC and one vWd pig had discrete stenoses; the stenoses affected the three coronary arteries and were significant (50% to 80%) in the NC and mild (greater than 25%) in the vWd pigs; no pigs showed myocardial lesions. Pigs with vWd are resistant to atherosclerosis of the aorta. To assess the resistance or susceptibility to coronary disease in these pigs, a longer follow-up study would be necessary.

Indium-111 tropolone, a new tracer for platelet labeling.

Platelets have been labeled with a new neutral, lipid-soluble metal complex of indium 111 (111In) and tropolone. Unlike oxine, which is soluble in ethyl alcohol, tropolone is soluble in isotonic saline. Platelet labeling with 111In tropolone can be performed in both acid-citrate-dextrose (ACD) plasma and ACD saline within two hours. Labeling efficiency has been 80% to 90%. 111In tropolone in ACD saline and ACD plasma at tropolone concentrations of 5 and 10 micrograms/ml, respectively, and incubation of the platelets with the tracer at room temperature for 20 minutes were optimal conditions for labeling. The authors have developed an ACD-saline kit for convenient preparation of 111In-labeled platelets. No adverse effect of 111In tropolone on platelets has been observed in studies of biodistribution, recovery, and survival of platelets in rabbits and dogs.