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Biomedical subjects

Rod J Rohrich

Publications and source records attributed to Rod J Rohrich.

At least 55 records · Page 3Linked to original sources

Pharmacokinetics and safety of epinephrine use in liposuction.

Patients are routinely exposed to high-dose epinephrine infiltration during large-volume liposuction. Because of the serious cardiovascular side-effect profile of catecholamine overdose, the authors examined the safety of larger-volume liposuction by assessing epinephrine pharmacokinetics. Five female volunteers with American Society of Anesthesiologists physical status of I or II, aged 29 to 40 years and weighing 75.9 to 95 kg, underwent liposuction. The wetting solution contained 7.3 mg (SEM, 0.7 mg) of epinephrine, corresponding to 0.09 mg/kg (0.04 mg/kg). Total plasma epinephrine and norepinephrine concentrations were assessed by high-performance liquid chromatography. Approximate exogenous epinephrine absorption was calculated after correction for estimated endogenous epinephrine production. Pharmacokinetic assessments were performed using standard equations. The total plasma epinephrine peak occurred at the final intraoperative reading (5 hours after induction) and was 323 pg/ml (24.8 pg/ml), three to four times maximum baseline resting levels. The norepinephrine level was slightly elevated throughout the study period, with a reversal of the normal epinephrine/norepinephrine ratio (<0.5:1) demonstrated intraoperatively (>5:1). Estimated time to peak exogenous epinephrine level ranged from 1 to 4 hours from the start of infiltration. Area under the plasma concentration versus time curve was approximately 2089 to 2610 pg x hour/ml. Peak exogenous epinephrine concentration was estimated to be 286 to 335 pg/ml. Clearance was 764,508 ml/hour and volume of distribution was 0.4 liter/kg (0.006 liter/kg). Total absorbed epinephrine was estimated, 1.8 mg to 2.2 mg, equivalent to 25 to 32 percent of the infiltrated dose. The reversal of the normal epinephrine/norepinephrine ratio and the fact that norepinephrine levels were within normal range implied that the majority of plasma epinephrine measured was exogenously infiltrated and not endogenously synthesized. On the basis of these observations, pharmacokinetic analyses were performed. Although unequivocal toxic epinephrine levels were not demonstrated, epinephrine peaks were three to four times the maximum observed in normal resting patients. Peak levels were comparable to those observed during major physiologic stresses, such as exercising to exhaustion, open abdominal surgery, or cross-clamping the aorta during surgical repair. Furthermore, epinephrine has been associated with myocardial infarction, arrhythmias, and fatal asystole in susceptible patients at these levels. Patients should be carefully screened for clinical evidence of hemodynamic and cardiac pathology before larger-volume liposuction is undertaken, as it may result in unnecessary high risk for patients who have preexisting cardiovascular disorders. Healthy American Society of Anesthesiologists physical status I or II patients should have sufficient cardiac reserve to tolerate these catecholamine levels.

Adult↗

Electrolyte and plasma enzyme analyses during large-volume liposuction.

Substantial fluid shifts occur during liposuction as wetting solution is infiltrated subcutaneously and fat is evacuated, causing potential electrolyte imbalances. In the porcine model for large-volume liposuction, plasma aspartate aminotransferase and alanine transaminase levels were elevated following liposuction. These results raised concerns for possible mechanical injury and/or lidocaine-induced hepatocellular toxicity in a clinical setting. The first objective of this human model study was to explore the effect of the liposuction procedure on electrolyte balance. The second objective was to determine whether elevated plasma aminotransferase levels were observed subsequent to large-volume liposuction. Five female volunteers underwent three-stage, ultrasound-assisted liposuction. Blood samples were collected perioperatively. Plasma levels of sodium, potassium, venous carbon dioxide, blood urea nitrogen, chloride, and creatinine were determined. Liver function analyte levels were measured, including albumin, total protein, aspartate aminotransferase, and alanine transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, and total bilirubin. To further define intracellular enzyme release, creatine kinase levels were measured. Mild hyponatremia was evident postoperatively (134 to 136 mmol/liter) in four patients. Hypokalemia was evident intraoperatively in all subjects (mean +/- SEM; 3.3 +/- 0.16 mmol/liter; range, 3.0 to 3.4 mmol/liter). Hypoalbuminemia and hypoproteinemia were observed throughout the study (baseline: 2.9 +/- 0.2 g/dl; range, 2.6 to 3.5 g/dl), decreasing to 10 to 40 percent 24 hours postoperatively (2.0 +/- 0.2 g/dl; range, 1.7 to 2.1 g/dl). Aspartate aminotransferase, alanine transaminase, and creatine kinase levels were significantly elevated after the procedure (190 +/- 47.1 U/liter, 50 +/- 7.7 U/liter, and 11,219 +/- 2556.7 U/liter, respectively) (p < 0.01). Release of antidiuretic hormone and even mildly hypotonic intravenous fluid infiltration have long been known to cause hyponatremia postoperatively. Intraoperative hypokalemia is associated with hypocarbia and respiratory alkalosis and the elevated epinephrine levels observed in the concurrent study. Factors having the greatest initial impact on diminished serum albumin and protein levels postoperatively are redistribution and hemodilution. Subsequent diminished viscosity may significantly affect postoperative hemodynamics. Elevated aspartate aminotransferase, alanine transaminase, and creatine kinase levels are associated with skeletal muscle injury, adipocyte lysis, and/or hepatic damage. Therefore, tissue injury is associated with large-volume liposuction as observed in several cellularly released enzymes. Future clinical studies are required to determine the degree of injury and specific tissues that are damaged or sensitive to mechanical trauma and/or drugs used in large-volume liposuction.

Alanine Transaminase↗

Hemodynamics, electrolytes, and organ histology of larger-volume liposuction in a porcine model.

Liposuction is a procedure that allows the surgical removal of excess adipose tissue in healthy individuals. Lipoplasty is commonly performed with few clinical side effects. However, with increased lipoaspirate volumes, complications have been reported. In addition, the abnormal appearance of fat cells in other tissues subsequent to lipoplasty has been reported in a small number of cases. The authors examined whether larger-volume lipoplasty, in the porcine model, resulted in disturbances in cardiac or pulmonary output levels, electrolytes, and liver chemistry analyses or alterations in organ histology. Nine adult porcine specimens were subjected to either lipoplasty (n = 6) with the superwet technique or no lipoplasty (n = 3). Using a Swan-Ganz catheter, cardiac output and pulmonary artery pressure measurements were obtained from initial placement before lipoplasty until 48 hours postoperatively. Blood analyte measurements were obtained. Upon euthanization, liver, kidney, and lung specimens were collected and tissue sections were prepared. No significant differences or trends were observed in cardiac parameters or blood analytes between control and experimental groups. Significant elevations in serum aspartate aminotransferase and alanine aminotransferase enzyme levels (p < 0.03) were observed in animals postoperatively (10 to 48 hours) subjected to lipoplasty compared with controls. Upon gross examination, the lung tissues of animals subjected to lipoplasty unexpectedly demonstrated patchy petechial hemorrhages on the pleural surface. Tissue sections revealed marked hemorrhagic congestion and evidence of pulmonary edema. Fat emboli were also identified within the pulmonary and renal systems.

Alanine Transaminase↗

A prospective controlled assessment of microdermabrasion for damaged skin and fine rhytides.

Aged skin is characterized by rhytides but also by epidermal and dermal atrophy, rough skin texture, irregular pigmentation, telangiectasias, and laxity. Microdermabrasion is an office-based mechanical resurfacing technique alternative to traditional dermabrasion. It has been used in Europe since 1992 with great acceptance. The purpose of this study was to evaluate and quantify the degree of visible improvement in photodamaged skin and fine rhytides following a series of microdermabrasion treatments. A single operator treated 20 patients with varying degrees of photodamage and rhytides with a series of eight microdermabrasion treatments at 1-week intervals; 17 subjects completed the entire study protocol. Standardized photographic documentation was performed before and after each treatment, and a survey questionnaire was completed by each subject. Punch biopsy specimens (3 mm) were collected on treated and matched nontreated control sites and evaluated for histological characteristics. Preprocedure and postprocedure photographs were rated on a 5-point scale by independent blinded observers. A total of 30 blinded observers (16 plastic surgeons and 14 laypersons) rated all photographs. The results showed that all observers rated a significant improvement of hyperchromic discoloration (p = 0.004), while only nonmedical observers observed improvement in fine rhytides. All patients were very satisfied with the results. Common side effects were mild to moderate discomfort occurring on bony areas during the treatment and an itching and tingling sensation for 2 days after treatment. No infections or scars were observed postoperatively. The average epidermal thickness in the untreated samples was 103 +/- 23 microM (mean +/- SD) before treatment compared with 148 +/- 41 microM after treatment (p < 0.001). Histologic analysis of the matched punch biopsy specimens showed an increase in organized collagen in treated versus nontreated sites. Treatment of aged skin using a series of microdermabrasion treatments is an effective, noninvasive method of skin rejuvenation with minimal risk and patient downtime. It is safe and improves skin quality by minimizing certain hyperchromic pigmentations.

Adult↗

In search of improved fat transfer viability: a quantitative analysis of the role of centrifugation and harvest site.

Fat grafting is an unpredictable procedure that continues to challenge the field of plastic surgery due to irregular resorption. Applications for this procedure are broad in both reconstructive and cosmetic plastic surgery. Fat grafts are carefully obtained and manipulated to obtain better graft takes and results, yet there is no universal agreement on what constitutes an ideal methodology. The present study examines adipocyte viability from four commonly used donor sites in five subjects. No statistical differences in adipocyte viability were demonstrated among abdominal fat, thigh fat, flank fat, or knee fat donor sites that were immediately removed and untreated (p < 0.225). In addition, no differences were observed in representative tissue samples that were removed and centrifuged (thigh, p = 0.508; knee, p = 0.302; flank, p = 0.088; abdomen, p = 0.533). On the basis of these quantitative data, neither harvest location nor centrifugation demonstrated any advantage in terms of lipocyte viability. Fat tissue transfers from these common sites may be considered equal, and centrifugation does not appear to enhance immediate fat tissue viability before implantation.

Adipocytes↗

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