Significant Changes in Blood Pressure, Glucose, and Lipids with Gastric Bypass Surgery

p < 0.01) and systemic blood pressure ( p < 0.05). Weight loss with GBP was also associated with significant reductions in the apoprotein B-containing lipoproteins and the triglyceride and cholesterol composition of these particles. There was a trend ( p < 0.10) toward increased serum levels of high density lipoprotein (HDL)-cholesterol following GBP, and significant ( p < 0.05) improvement in HDL subfraction distribution and composition. These findings demonstrate the effectiveness of GBP in inducing metabolic changes in the MO population, which may reduce the risk of coronary artery disease, diabetes, and hypertension.     

Skin Vasodilator Function and Vasomotion in Patients with Morbid Obesity: Effects of Gastric Bypass Surgery

Obesity-associated microvascular dysfunction (MVD) involves different body tissues, including skin, and concurs to increased cardiovascular risk in obese patients (Ob-P). Generalized improvement of MVD is an important goal in obesity treatment. Since skin MVD mirrors generalized systemic MVD, skin microvascular investigation in prospective studies in Ob-P may surrogate microvascular investigation in organs more important for cardiovascular risk of the studied patients. In this prospective study, we measured forearm skin post-occlusive reactive hyperaemia (PORH), as percentage flow increase from baseline, and skin vasomotion in 37 Ob-P before Roux-en-Y gastric bypass (RYGB), and in 24 of them about 1 year after RYGB, using laser Doppler flowmetry (LDF). The spectral contribution of skin LDF signal oscillations in the frequency intervals of 0.01–0.02 Hz, 0.02–0.06 Hz, and 0.06–0.2 Hz—corresponding to endothelial-, sympathetic-, and myogenic-dependent vasomotion, respectively, was measured by means of spectral Fourier analysis. The same measurements were also performed in 28 healthy, lean subjects (HLS). Before RYGB, Ob-P had a significant reduction in PORH and in the all vasomotion parameters investigated, compared with HLS. After RYGB, Ob-P who completed the follow-up, had a significant weight loss (∼40 kg on average), together with a full normalisation in PORH and in vasomotion parameters, regardless of diabetes status. Surgically induced sustained weight loss resulted in full normalisation of skin microvascolar function in Ob-P about 1 year after RYGB. This result suggests a beneficial effect of sustained weight loss on generalized MVD of the studied Ob-P.     

Influence of Anaesthesia on Blood Flow to the Calves During Surgery

The blood flow to the calves during abdominal surgery under different kinds of general anaesthesia was measured by strain gauge plethysmography in 12 patients. The volume flow increased 100% during surgery in both light and deep anaesthesia, caused by a decrease in peripheral resistance. The increase in volume flow could partly be explained by the anaesthesia itself, possibly induced by the use of a nitrous oxide-oxygen gas mixture. The surgical procedure caused a further increase in volume flow. Possible underlying mechanisms are discussed.     

Intraoperative Endoscopic Assessment of the Pouch and Anastomosis During Laparoscopic Roux-en-Y Gastric Bypass

As an advanced surgical procedure, laparoscopic Roux-en-Y gastric bypass (LRYGB) is associated with considerable morbidity, especially in the learning curve period. The aim of this study was to evaluate the role of endoscopy during LRYGB surgery in assessing the gastric pouch and anastomosis for air leak, bleeding, and structure at the beginning of a bariatric surgery program. Patients who underwent LRYGB for morbid obesity between May 2008 and May 2009 were included in this study. After the completion of the anastomosis, an endoscopic examination was carried out. The transection line and anastomosis site were examined for bleeding and patency and inspected for air leak under laparoscopic vision. Thirteen morbidly obese patients (mean body mass index, 48.0 ± 6.8 kg/m²) were evaluated by endoscopic examination during the LRYGB operation. None of the cases had bleeding at the transection line or anastomosis site. In two patients, air leak test was positive and the anastomosis was reinforced with additional sutures. All the patients, including those with positive air leak test, were discharged from the hospital with no leak complications. After a mean follow-up of 9.1 ± 5.5 months, except for the patient who underwent balloon dilatation, no other patient had anastomotic stricture. Intraoperative endoscopy is invaluable in the assessment of bleeding, anastomotic patency, and air leak during LRYGB, and it might be a helpful auxiliary tool to decrease morbidity during the learning curve period. Also, it helps solve intraoperative problems during the surgery so that postoperative complications might be prevented.     

Effect of Laparoscopic versus Open Gastric Bypass Surgery on Postoperative Pain and Bowel Function

Background: This study was designed to assess postoperative pain and bowel function in morbidly obese patients undergoing Roux-en-Y gastric bypass (RYGBP) performed either by open or laparoscopic technique. Methods: We prospectively studied patients scheduled for RYGBP between July 2002 and June 2003. Patients were assigned to the laparoscopic or open procedure by one surgeon. All patients received patient controlled analgesia (PCA) with intravenous morphine and rectal naproxen 500 mg every 12 hours. Postoperative analgesia was assessed daily using a visual analog scale (VAS) at rest, on walking and coughing. The amount of morphine used during the first 48 hours, the time of return of gastrointestinal motility and the time until first oral food intake were recorded. Results: 53 patients were enrolled and studied (laparoscopic group n=33, open group n=20). Patients undergoing laparoscopic RYGBP requested less morphine (P=0.0001) and showed lower VAS pain scores than patients undergoing open RYGBP. The return of bowel movement in the laparoscopic group occurred 1 day earlier than in the open group (P=0.01). The time to first passage of gas (P=0.01) and oral food intake (P=0.06) was shorter after laparoscopic than after open RYGBP. Patients in the laparoscopic group were discharged 1? days earlier than patients in the open group (P=0.01). Conclusion: The laparoscopic RYGBP operation was associated with less postoperative pain and morphine consumption than the open RYGBP, thereby facilitating an earlier recovery of intestinal motility.     

Metabolic Characterization of Nondiabetic Severely Obese Patients Undergoing Roux-en-Y Gastric Bypass: Preoperative Classification Predicts the Effects of Gastric Bypass on Insulin–Glucose Homeostasis

Introduction Obese individuals may have normal insulin–glucose homeostasis, insulin resistance, or diabetes mellitus. Whereas gastric bypass cures insulin resistance and diabetes mellitus, its effects on normal physiology have not been described. We studied insulin resistance and β-cell function for patients undergoing gastric bypass. Methods One hundred thirty-eight patients undergoing gastric bypass had fasting insulin and glucose levels drawn on days 0, 12, 40, 180, and 365. Thirty-one (22%) patients with diabetes mellitus were excluded from this analysis. Homeostatic model of assessment was used to estimate insulin resistance, insulin sensitivity, and β-cell function. Based on this model, patients were categorized as high insulin resistance if their insulin resistance was >2.3. Results Body mass index did not correlate with insulin resistance. Forty-seven (34%) patients were categorized as high insulin resistance. Correction of insulin resistance for this group occurred by 12 days postoperatively. Sixty (43%) patients were categorized as low insulin resistance. They demonstrated an increase of β-cell function by 12 days postoperatively, which returned to baseline by 6 months. At 1 year postoperatively, the low insulin resistance group had significantly higher β-cell function per degree of insulin sensitivity. Conclusions Adipose mass alone cannot explain insulin resistance. Severely obese individuals can be categorized by degree of insulin resistance, and the effect of gastric bypass depends upon this preoperative physiology.     

Improvement in Peripheral Glucose Uptake After Gastric Bypass Surgery Is Observed Only After Substantial Weight Loss Has Occurred and Correlates with the Magnitude of Weight Lost

Introduction  

Altered gut and pancreatic hormone secretion may bolster resolution of insulin resistance after Roux-en-Y gastric bypass (RYGB), but the independent effects of weight loss and hormonal secretion on peripheral glucose disposal are unknown.     

Effects of Pulsatile Assistance and Nonpulsatile Flow on Subendocardial Perfusion During Cardiopulmonary Bypass

We compared the effects of pulsatile and nonpulsatile perfusion in 12 dogs on extracorporeal circulation. In beating empty and fibrillating hearts at 37° and 28°, coronary blood flow was measured by flowmeter and microspheres at diastolic pressures ranging between 50 and 130 mm Hg.At fixed systemic flow rates (range, 600 to 2,400 ml/min), pulsatile perfusion produced a transient (3 to 4 second) augmentation of diastolic pressure and then resulted in the following: (1) decreased peripheral vascular resistance (p < 0.05); (2) unchanged peak diastolic pressure (compared with nonpulsatile perfusion); (3) decreased mean aortic pressure (6 to 37%) (p < 0.05); (4) decreased coronary blood flow (10 to 45%) (p < 0.05); and (5) decreased subendocardial blood flow (from 512 to 438 ml/100 gm/min) (p < 0.05). Pulsatile perfusion in beating hearts (37° or 28°) did not reduce subendocardial vascular resistance, but did improve subendocardial perfusion by 27% and 36% in fibrillating hearts at 37° and 28°, respectively.We conclude that with the exception of ventricular fibrillation, pulsatile assistance offers no advantage over nonpulsatile perfusion and has the potential disadvantage of requiring higher pump flow rates to achieve any desired level of coronary and subendocardial flow.     

Silicone-Ring Roux-en-Y Gastric Bypass in the Treatment of Obesity: Effects of Laparoscopic Versus Laparotomic Surgery on Respiration

Background  

The objective of this study was to compare the effects of silicone-ring Roux-en-Y gastric bypass carried out by laparoscopy versus that accomplished by laparotomy on pulmonary function.     

Laparoscopic Gastric Bypass: Development of Technique,Respiratory Function,and Long-Term Outcome

Background: Roux-en-Y gastric bypass (RYGBP) is the preferred operation for the treatment of morbid obesity by many surgeons. Hereby we present the process by which laparoscopic RYGBP (LRYGBP) developed at our institution. Methods: Perioperative morbidity was recorded from 150 consecutive morbidly obese patients operated upon by RYGBP from August 1994 to March 2002. The first 76 consecutive patients have been followed up to 5 years postoperatively. A subgroup of 40 patients was recruited to evaluate the postoperative lung function in a randomized study between receiving and not receiving prophylactic chest physiotherapy. Results: In the whole series, there were 4 conversions to open surgery, 5 leaks, 12 postoperative bleedings and 1 intestinal obstruction. 1 patient succumbed after developing acute dilatation of the bypassed stomach. Respiratory function deteriorated significantly in all patients in the early postoperative period, irrespective if given physiotherapy. During the follow-up period, 3 patients developed mechanical obstruction of the Roux limb. Another patient had a perforated ulcer at the proximal pouch. Weight reduction averaged 70% of excess body weight at 2 years after surgery. Conclusions: LRYGBP is an effective treatment for morbid obesity. During the initial development, we experienced a number of serious complications. The complication rate decreased over time. Postoperative lung function was markedly impaired, but there were no beneficial effects of chest physiotherapy. Long-term weight loss after LRYGBP seems to be comparable to what has been reported after open RYGBP.     

Effects of Halothane and Methoxyflurane on Pulmonary Resistance to Gas Flow During Lung Bypass

Lung-mechanics during cardio-pulmonary bypass were studied in 20 patients operated upon for heart disease. Pulmonary resistance to gas flow, pressures and compliance were continuously measured with the aid of a respiratory analogue computer. Measurements were made at constant blood gas tensions in the oxygenator with various combinations of inspired carbon dioxide fractions with oxygen, halothane and methoxyflurane. Oxygen with carbon dioxide proved to be a strong broncho-dilatator as well as oxygen + halothane with decreases in resistance of 15–8% of control values, respectively. This was combined with an increase in compliance of 6–5%. In contrast to halothane and carbon dioxide, the mixture of oxygen + methoxyflurane resulted in an increase of resistance with 6%. Methoxyflurane and carbon dioxide resulted in a decrease of the resistance with 16%. It is concluded that halothans and carbon dioxide have a direct action on bronchial smooth muscles, but that such an effect is lacking for methoxyflurane. If diethyl-ether, which was not tested due to explosive risks, has similar pharmacological properties as methoxyflurane then the beneficial effect of diethyl-ether in bronchoconstrictive conditions ought to be elicited through adrenergic stimulation with the liberation of cathecholamines into the pulmonary circulation. Such an action of diethyl-ether is known to support the myocardial function during anaesthesia. The study of anaesthetic agents on smooth muscles of the bronchial system during conditions of lung bypass is of interest, as conclusions can be drawn as to the most suitable anaesthetics to be given to patients with bronchoconstrictive disease. The results indicate that halothane is such an agent in contrast to methoxyflurane.     

Effects of Xenon on Cerebral Blood Flow and Cerebral Glucose Utilization in Rats

Background: The effects of xenon inhalation on mean and local cerebral blood flow (CBF) and mean and local cerebral glucose utilization (CGU) were investigated using iodo-[14C]antipyrine and [14C]deoxyglucose autoradiography.

Methods: Rats were randomly assigned to the following groups: conscious controls (n = 12); 30% (n = 12) or 70% xenon (n = 12) for 45 min for the measurement of local CBF and CGU; or 70% xenon for 2 min (n = 6) or 5 min (n = 6) for the measurement of local CBF only.

Results: Compared with conscious controls, steady state inhalation of 30 or 70% xenon did not result in changes of either local or mean CBF. However, mean CBF increased by 48 and 37% after 2 and 5 min of 70% xenon short inhalation, which was entirely caused by an increased local CBF in cortical brain regions. Mean CGU determined during steady state 30 or 70% xenon inhalation remained unchanged, although local CGU decreased in 7 (30% xenon) and 18 (70% xenon) of the 40 examined brain regions. The correlation between CBF and CGU in 40 local brain structures was maintained during steady state inhalation of both 30 and 70% xenon inhalation, although at an increased slope at 70% xenon.     

Role of Proximal Intestinal Glucose Sensing and Metabolism in the Blood Glucose Control in Type 2 Diabetic Rats After Duodenal Jejunal Bypass Surgery

Obesity Surgery - Although gastric surgery can significantly improve blood glucose homeostasis in type 2 diabetes mellitus (T2DM), its mechanism remains unclear. This study evaluated the role of...     

Effects of Extreme Hemodilution during Cardiac Surgery on Cognitive Function in the Elderly

Background: Strategies for neuroprotection including hypothermia and hemodilution have been routinely practiced since the inception of cardiopulmonary bypass. Yet postoperative neurocognitive deficits that diminish the quality of life of cardiac surgery patients are frequent. Because there is uncertainty regarding the impact of hemodilution on perioperative organ function, the authors hypothesized that extreme hemodilution during cardiac surgery would increase the frequency and severity of postoperative neurocognitive deficits.

Methods: Patients undergoing coronary artery bypass grafting surgery were randomly assigned to either moderate hemodilution (hematocrit on cardiopulmonary bypass >=27%) or profound hemodilution (hematocrit on cardiopulmonary bypass of 15-18%). Cognitive function was measured preoperatively and 6 weeks postoperatively. The effect of hemodilution on postoperative cognition was tested using multivariable modeling accounting for age, years of education, and baseline levels of cognition.

Results: After randomization of 108 patients, the trial was terminated by the Data Safety and Monitoring Board due to the significant occurrence of adverse events, which primarily involved pulmonary complications in the moderate hemodilution group. Multivariable analysis revealed an interaction between hemodilution and age wherein older patients in the profound hemodilution group experienced greater neurocognitive decline (P = 0.03).     

The Effect of Controlled Hyperventilation on Cerebral Blood Flow and Oxygen Uptake in Patients with Brain Lesions

Der klinische Verlauf von 63 Patienten, die mit Hirnläsionen verschiedener Genese und Schwere ins Krankenhaus eingeliefert worden waren, wurde studiert. Bei allen Fällen wurden der arterielle und der cerebral-venöse Säure-Basen-Status und die Sauerstoffspannung gemessen, manchmal zu wiederholten Malen; ferner wurde die arterio-venäse Sauerstoffdifferenz berechnet. Bei 21 Patienten wurde die Hirndurchblutung mit Hilfe der Xenon¹³³-Technik gemessen; bei 10 Patienten wurde diese Untersuchung sowohl bei Spontanatmung als auch bei kontrollierter Ventilation durchgefährt. Die dabei erhaltenen Resultate deuten darauf hin, daß kontrollierte Hyperventilation die zerebrale Durchblutung vermindert und die arterio-venöse Sauerstoffdifferenz erhöht; die Sauerstoffaufnahme des Gehirns bleibt dabei praktisch unverändert. Zwischen der Tiefe der Be-wußtlossigkeit und dem klinischen Ausgang oder der zerebralen Durchblutung und der Sauerstoffaufnahme konnten keine Korrelationen gefunden werden, und zwar weder bei spontaner noch bei kontrollierten Ventilation. Obwohl kontrollierte mäßige Hyperventilation den klinischen Ausgang bei Patienten mit Hirnläsionen gänstig zu beeinflussen scheint, wird dennoch der Schluß gezogen, daß die Messungen der halbseitigen Hirndurchblutung und der Sauerstoffaufnahme unverläBliche Methoden zur Erstellung einer Prognose sind.