Search

BACKGROUND AND AIMS: To assess the effects of bariatric surgery (BS) on peripheral endothelial function and on coronary microvascular dilator function. METHODS AND RESULTS: We studied 50 morbidly obese patients (age 38 ± 9, 13 M) who underwent BS and 20 comparable obese controls (age 41 ± 11, 6 M) without any evidence of cardiovascular disease. Peripheral vascular dilator function was assessed by brachial artery diameter changes in response to post-ischemic forearm hyperaemia (flow-mediated dilation, FMD). Coronary microvascular function was assessed by measuring coronary blood flow (CBF) velocity response to i.v. adenosine and to cold pressor test (CPT) in the left anterior descending coronary artery by transthoracic Doppler echocardiography. The tests were performed at baseline and at 3-month follow-up. At baseline, FMD and CBF response to adenosine and CPT were similar in the 2 groups. Compared to baseline, FMD at follow-up improved significantly in BS patients (5.9 ± 2.7% to 8.8 ± 2.4%, p < 0.01), but not in controls (6.3 ± 3.2% vs. 6.4 ± 3.1%, p = 0.41). Similarly, a significant improvement of CBF response to adenosine (1.63 ± 0.47 to 2.45 ± 0.57, p < 0.01) and to CPT (1.43 ± 0.26 to 2.13 ± 0.55, p < 0.01) was observed in BS patients but not in controls (1.55 ± 0.38 vs. 1.53 ± 0.37, p = 0.85; and 1.37 ± 0.26 vs. 1.34 ± 0.21, p = 0.48, respectively). The favourable vascular effects of BS were similar independently of the presence and changes of other known cardiovascular risk factors and of basal values and changes of serum C-reactive protein levels. CONCLUSIONS: Our data show that, in morbidly obese patients, together with peripheral endothelial function, BS also improves coronary microvascular function. These effects suggest global improvement of vascular function which can contribute significantly to the reduction of cardiovascular risk by BS reported in previous studies.

Background: In obese patients, concomitant use of clonidine and ketamine might be suitable to reduce the doses and minimize the undesired side effects of anesthetic and analgesic drugs. In this study, we evaluated the perioperative effects of administration of clonidine and ketamine in morbidly obese patients undergoing weight loss surgery at a university hospital in Rome, Italy. Methods: A total of 50 morbidly obese patients undergoing open biliopancreatic diversion for weight loss surgery were enrolled. The patients were randomly allocated into a study group (n = 23) receiving a slow infusion of ketamine-clonidine before anesthesia induction and a control group (n = 27) who received standard anesthesia. The hemodynamic profile, intraoperative end-tidal sevoflurane and opioid consumption, tracheal extubation time, Aldrete score, postoperative pain assessment by visual analog scale, and analgesic requirements were recorded. Results: The patients in the study group required less end-tidal sevoflurane, lower total doses of fentanyl (3.8 ± 0.3 Î3/kg actual body weight versus 5.0 ± 0.2 Î3/kg actual body weight, respectively; P <.05) and had a shorter time to extubation (15.1 ± 5 min versus 28.2 ± 6 min, P <.05). The Aldrete score was significantly better in the postanesthesia care unit in the study group. The study group consumed less tramadol than did the control group (138 ± 57 mg versus 252 ± 78 mg, P <.05) and had a lower visual analog scale score postoperatively during the first 6 hours. Conclusion: The preoperative administration of low doses of ketamine and clonidine at induction appears to provide early extubation and diminished postoperative analgesic requirements in morbidly obese patients undergoing open bariatric surgery. © 2009 American Society for Metabolic and Bariatric Surgery.

Biliopancreatic diversion (BPD) is a surgical procedure performed in patients with untreatable obesity and insulin resistance. The demonstrated metabolic and hormonal results of this procedure include: the reversal of insulin resistance, an increase in diet-induced thermogenesis and modifications of gut hormones, such as gastrin, enteroglucagone, neurotensin and cholecystokinin. On the other hand, obesity is a condition of increased oxidative stress; however few studies have investigated antioxidant systems in obese persons with BPD. In order to evaluate the metabolic status and antioxidant systems in such patients, we studied a group of 11 morbidly obese patients, aged 28-62 years, with a mean BMI of 54.71± 2.52 kg/m2, before and after successful BPD (mean post-BPD BMI 44.68 ± 1.51 kg/m2). A control group composed of ten slightly overweight women, with a mean BMI of 28.5±0.72 kg/m2, was also studied. Coenzyme Q10 (CoQ10) levels (also normalized for cholesterol levels) and Total Antioxidant Capacity (TAC) in blood plasma were assessed in these populations. The most striking datum was the extremely low level of CoQ10 in postoperative period (0.34±0.16 vs 0.66±0.09µg/ml, p=0.04); also the data corrected for cholesterol levels presented the same pattern, with a more marked significance (152.46±11.13 vs 186.4±17.98 nmol/mmol, p=0.001).This could be due to lipid malabsorption after surgery. In fact, the pre-BPD data present all the metabolic and hormonal characteristics of severe obesity and, after BPD, there was a net improvement in the metabolic parameters. The first pathophysiological phenomenon seems to be lipid malabsorption that has been argued to be cause of insulin resistance reversion. This metabolic interpretation is also confirmed by the absence of significant variations of TAC (57.5±5.3 vs 66±5.3). The mechanisms of these phenomena remain to be established. These data suggest the importance of correcting post-surgical metabolic complications, in these clinica

Determinants of improvement in oxygenation consequent to reverse Trendelenburg position in anesthetized morbidly obese patients.

Background: Anesthetized morbidly obese patients often exhibit impaired pulmonary gas exchanges, mostly because of a reduction in functional residual capacity. At present, several approaches are suggested to ventilate these patients. Methods: The efficiency of positive end-expiratory pressure (PEEP) and reverse Trendelenburg position (RTP) were compared in order to improve oxygenation in 20 morbidly obese patients undergoing bariatric surgery. Results: Both PEEP and RTP determined a significant decrease in alveolar-arterial oxygen difference and an increase in total respiratory compliance (Ctot). RTP resulted in lower airway pressures than PEEP with similar improvements in Ctot and oxygenation. Concerning hemodynamic parameters, cardiac output (CO) significantly decreased with both PEEP and RTP. Conclusions: RTP and PEEP can be considered adequate ventilatory settings for morbidly obese patients, without any significant difference with regard to gas exchange improvement. However, the decrease in CO may partially counteract the beneficial effects on oxygenation of these ventilatory settings.