Impact of Shorter-acting Neuromuscular Blocking Agents on Fast-track Recovery of the Cardiac Surgical Patient

Background: Residual paralysis associated with the use of long-acting muscle relaxants can delay recovery from anesthesia and surgery. The authors tested the hypothesis that use of shorter-acting neuromuscular blocking agents is associated with reductions in tracheal extubation times and intensive care unit (ICU) length of stay in patients undergoing cardiac surgery with cardiopulmonary bypass.

Methods: One hundred ten patients scheduled for elective coronary artery bypass grafting or single valve surgery were randomized prospectively to receive either pancuronium or rocuronium intraoperatively. Anesthetic management and muscle relaxant maintenance dosing were standardized. In the ICU, the time required to wean ventilatory support, the duration of tracheal intubation, and length of stay were recorded. Subjects were asked to quantify generalized muscle weakness as they awakened in the ICU and again after tracheal extubation.

Results: Complete data were collected on 51 patients in the pancuronium group and 52 patients in the rocuronium group. No differences were found between the groups in anesthetic, surgical, or ICU management. Significant increases in the duration of weaning of ventilatory support were observed in patients who received pancuronium (median, 180 min; range, 50-780 min) compared with the rocuronium group (median, 110 min; range, 45-250 min). Tracheal extubation was significantly delayed in the pancuronium group (median, 500 min; range, 240-1,305 min) compared with the rocuronium group (median, 350 min; range, 210-1,140 min). Subjects in the pancuronium group experienced more mild to severe weakness in the ICU. However, the choice of muscle relaxant did not influence ICU length of stay.     

Photodynamic therapy inhibits transforming growth factor β activity associated with vascular smooth muscle cell injury

Purpose: The multifunctional cytokine, transforming growth factor β1 (TGF-β), plays an important role in the development of injury-associated intimal hyperplasia (IH). Strategies to suppress local TGF-β activity may have a clinical potential to prevent restenosis caused by IH. Photodynamic therapy (PDT) involves the local generation of cytotoxic free radicals by light activation of photosensitizer dyes and has been shown to inhibit experimental IH. This study investigated whether PDT-generated free radicals can affect TGF-β activity in a biologic system using vascular smooth muscle cells (SMCs).Methods: The release and activation of TGF-β by injured SMCs in culture was compared between mechanical injury and PDT. Mechanical injury was induced with a rubber policeman, and PDT was performed with the photosensitizer chloroaluminum sulfonated phthalocyanine (5 μg/ml) and 675 nm laser light at subtherapeutic 10 J/cm² and the in vivo therapeutic dose of 100 J/cm². Cell viability was assessed by the tetrazolium salt conversion assay, and active and total (active + latent) TGF-β was determined by enzyme-linked immunosorbent assay in the conditioned media of SMCs 24 hours after treatment. Functional TGF-β activity was assessed by inhibition of endothelial cell mitogenesis.Results: Both forms of injury severely reduced (p < 0.0005) SMC viability to less than 15%. In untreated SMC conditioned media, only 14.5% of the total TGF-β was active (27.7 ± 8.7 pg per 1 × 10⁵ cells). However, after mechanical injury and PDT with 10 J/cm², there was a significant increase (p < 0.02) in active TGF-β (60.1 ± 10.1 pg and 48.6 ± 21.0 pg, respectively), despite a total reduction of approximately 50%. In contrast to this result, PDT with 100 J/cm² did not result in increased levels of active TGF-β (8.1 ± 3.5 pg), despite having similar levels of total TGF-β. Consequently, the conditioned media of SMCs that had 100 J/cm² PDT did not inhibit endothelial cell mitogenesis as compared with the conditioned media of SMCs with mechanical injury and 10 J/cm² PDT (p < 0.0002).Conclusions: This report describes two novel findings: (1) injury to SMCs in vitro induces the conversion of biologically latent TGF-β to active TGF-β; and (2) the therapeutic PDT dose interferes with this injury activation process. This study substantiates the concept of local cytokine inhibition by PDT in a biologic system and provides new insights into the mechanisms of PDT-mediated inhibition of experimental IH. (J Vasc Surg 1997;25:1033-43.)     

Serum ionic fluoride levels in haemodialysis and continuous ambulatory peritoneal dialysis patients

High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 +/- 0.350 microM/l. Males in control group showed slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs 2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 microM/l, posing the risk of renal osteodystrophy.      

Cardia: study design, recruitment, and some characteristics of the examined subjects

In 1984, a prospective cohort study, Coronary Artery Risk Development in Young Adults (CARDIA) was initiated to investigate life-style and other factors that influence, favorably and unfavorably, the evolution of coronary heart disease risk factors during young adulthood. After a year of planning and protocol development, 5,116 black and white women and men, age 18-30 years, were recruited and examined in four urban areas: Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota, and Oakland, California. The initial examination included carefully standardized measurements of major risk factors as well as assessments of psychosocial, dietary, and exercise-related characteristics that might influence them, or that might be independent risk factors. This report presents the recruitment and examination methods as well as the mean levels of blood pressure, total plasma cholesterol, height, weight and body mass index, and the prevalence of cigarette smoking by age, sex, race and educational level. Compared to recent national samples, smoking is less prevalent in CARDIA participants, and weight tends to be greater. Cholesterol levels are representative and somewhat lower blood pressures in CARDIA are probably, at least in part, due to differences in measurement methods. Especially noteworthy among several differences in risk factor levels by demographic subgroup, were a higher body mass index among black than white women and much higher prevalence of cigarette smoking among persons with no more than a high school education than among those with more education.     

44Sacral extracorporeal magnetic stimulation is an effective treatment for pelvic floor dyssynergia; Comparative study with biofeedback therapy

Background: Recent development of extracorporeal magnetic stimulation (ECMS) which uses current‐changing magnetic fields allows the induction of electrical stimulation in the desired deep tissue. Recent study showed the sacral nerve stimulation reduces corticoanal excitability that may play a functional role in anal continence mechanisms. Preliminary study shows that ECMS of sacral nerve can modify pelvic floor function and expel rectal balloon in patients with pelvic floor dyssynergia (PFD). Aims: To evaluate the effect of ECMS compared with biofeedback therapy (BF) in patients with PFD. Methods and Materials: Thirty‐eight patients who fulfilled Rome II criteria for PFD by colon transit time and anorectal function tests, were randomly treated with 8 sessions of ECMS (2/weeks; n = 19) at prone position or BF (2/weeks; n = 19) at sitting position. Stimulation parameters were set at 50–80% of maximum intensity, 10 and 50 Hz frequency, 3 s burst length with 3 and 6 s off using arm‐typed stimulator (BioCom‐1000, Mcube Co., Korea). Symptom scores for constipation with/without anorectal function test were repeatedly measured after each treatment. Response was defined as 50% or more decreased symptom score after treatment (partial response: 30–50%, poor: <30%). Results: Fifteen patients (age 49.1 ± 13.4 years, mean ± SD; 4 men) completed 8 session of BF and 14 patients (54.5 ± 17.6 years, 3 men) completed 8 session of ECMS. Four patients of BF group discontinued treatment due to unsatisfactory therapeutic effect (n = 1) and withdrew consent (n = 3) and 5 patients of ECMS group discontinued treatment because of same reasons (n = 1, 4). Total symptom scores were significantly decreased after treatment of 8 session in both treatment groups (13.4 ± 6.6 vs. 4.3 ± 4.0 for BF, p = 0.009; 14.9 ± 5.6 vs. 3.4 ± 4.0 for ECMS, p < 0.001). Bowel movements per week were also significantly increased after treatment in both groups (median 2 vs. 7 for BF, p = 0.035; median 2 vs. 7 for ECMS, p = 0.008). Thirteen out of 15 patients showed response in BF group and 12 out of 14 showed good response in ECMS group. No adverse effects in both groups. Conclusions: ECMS is as effective as BF for the treatment of PFD. Long‐term effect of ECMS for the patients with pelvic floor dyssynergia need to be evaluated in the near future.