Neal Fleming

Comparison of pulmonary function and postoperative pain after laparoscopic versus open gastric bypass: A randomized trial

BACKGROUND Impairment of pulmonary function is common after upper abdominal operations. The purpose of this study was to compare postoperative pulmonary function and analgesic requirements in patients undergoing either laparoscopic or open Roux-en-Y gastric bypass (GBP). STUDY DESIGN Seventy patients with a body mass index of 40 to 60 kg/m2 were randomly assigned to undergo laparoscopic (n = 36) or open (n = 34) GBP. The two groups were similar in age, gender, body mass index, pulmonary history, and baseline pulmonary function. Pulmonary function studies were performed preoperatively and on postoperative days 1, 2, 3, and 7. Oxygen saturation and chest radiographs were performed on both groups preoperatively and on postoperative day 1. Postoperative pain was evaluated using a visual analog scale and the amount of narcotic consumed was recorded. Data are presented as mean +/- standard deviation. RESULTS Laparoscopic GBP patients had significantly less impairment of pulmonary function than open GBP patients on the first three postoperative days (p < 0.05). By the 7th postoperative day, all pulmonary function parameters in the laparoscopic GBP group had returned to within preoperative levels, but only one parameter (peak expiratory flow) had returned to preoperative levels in the open GBP group. On the first postoperative day, laparoscopic GBP patients used less morphine than open GBP patients (46 +/- 31 mg versus 76 +/- 39 mg, respectively, p < 0.001), and visual analog scale pain scores at rest and during mobilization were lower after laparoscopic GBP than after open GBP (p < 0.05). Fewer patients after laparoscopic GBP than after open GBP developed hypoxemia (31% versus 76%, p < 0.001) and segmental atelectasis (6% versus 55%, p = 0.003). CONCLUSION Laparoscopic gastric bypass resulted in less postoperative suppression of pulmonary function, decreased pain, improved oxygenation, and less atelectasis than open gastric bypass.

Perioperative Dexmedetomidine Improves Outcomes of Cardiac Surgery

Background— Cardiac surgery is associated with a high risk of cardiovascular and other complications that translate into increased mortality and healthcare costs. This retrospective study was designed to determine whether the perioperative use of dexmedetomidine could reduce the incidence of complications and mortality after cardiac surgery. Methods and Results— A total of 1134 patients who underwent coronary artery bypass surgery and coronary artery bypass surgery plus valvular or other procedures were included. Of them, 568 received intravenous dexmedetomidine infusion and 566 did not. Data were adjusted with propensity scores, and multivariate logistic regression was used. The primary outcomes measured included mortality and postoperative major adverse cardiocerebral events (stroke, coma, perioperative myocardial infarction, heart block, or cardiac arrest). Secondary outcomes included renal failure, sepsis, delirium, postoperative ventilation hours, length of hospital stay, and 30-day readmission. Dexmedetomidine use significantly reduced postoperative in-hospital (1.23% versus 4.59%; adjusted odds ratio, 0.34; 95% confidence interval, 0.192–0.614; P<0.0001), 30-day (1.76% versus 5.12%; adjusted odds ratio, 0.39; 95% confidence interval, 0.226–0.655; P<0.0001), and 1-year (3.17% versus 7.95%; adjusted odds ratio, 0.47; 95% confidence interval, 0.312–0.701; P=0.0002) mortality. Perioperative dexmedetomidine therapy also reduced the risk of overall complications (47.18% versus 54.06%; adjusted odds ratio, 0.80; 95% confidence interval, 0.68–0.96; P=0.0136) and delirium (5.46% versus 7.42%; adjusted odds ratio, 0.53; 95% confidence interval, 0.37–0.75; P=0.0030). Conclusion— Perioperative dexmedetomidine use was associated with a decrease in postoperative mortality up to 1 year and decreased incidence of postoperative complications and delirium in patients undergoing cardiac surgery. Clinical Trial Registration— URL: www.clinicaltrials.gov. Unique identifier: NCT01683448.

Effect of prolonged pneumoperitoneum on intraoperative urine output during laparoscopic gastric bypass.

BACKGROUND Intraoperative oliguria is common during laparoscopic operations. The objective of this study was to evaluate the effects of prolonged pneumoperitoneum during laparoscopic gastric bypass (GBP) on intraoperative urine output and renal function. METHODS 104 patients with a body mass index between 40 and 60 kg/m2 were randomly assigned to laparoscopic (n = 54) or open (n = 50) GBP. Intraoperative urine output was recorded at 30-min intervals. Blood urea nitrogen and creatinine levels were measured at baseline and on postoperative days 1, 2, and 3. Levels of antidiuretic hormone, aldosterone, and plasma renin activity were also measured in a subset of laparoscopic (n = 22) and open (n = 24) GBP patients at baseline, 2 hours after surgical incision, and in the recovery room. RESULTS The laparoscopic and open groups were similar in age, gender, and body mass index. There was no significant difference in amount of intraoperative fluid administered between groups (5.4 +/- 1.6 L, laparoscopic versus 5.8 +/- 1.7 L, open), but operative time was longer in the laparoscopic group (232 min versus 200 min, p < 0.01). Urinary output during laparoscopic GBP was 64% lower than during open GBP at 1 hour after surgical incision (19 mL versus 55 mL, p < 0.01) and continued to remain lower than that of the open group by 31-50% throughout the operation. Postoperative blood urea nitrogen and creatinine levels remained within the normal range in both groups. Serum levels of antidiuretic hormone, aldosterone, and plasma renin activity peaked at 2 hours after surgical incision with no significant difference between the two groups. CONCLUSION Prolonged pneumoperitoneum during laparoscopic gastric bypass significantly reduced intraoperative urine output but did not adversely alter postoperative renal function.

Anesthetic Preconditioning Combined with Postconditioning Offers No Additional Benefit Over Preconditioning or Postconditioning Alone

BACKGROUND:Recent investigations demonstrate that anesthetic preconditioning and postconditioning reduce myocardial infarct size to a degree comparable to that achieved with ischemic preconditioning. We hypothesized that the combination of sevoflurane preconditioning and postconditioning would result in greater preservation of myocardium. METHODS:Langendorff perfused rat hearts were divided into four groups: control, preconditioning, postconditioning, and preconditioning plus postconditioning. During reperfusion, left ventricular function (left ventricular developed pressure, left ventricular end diastolic pressure, and dp/dt) were measured. At the end of reperfusion, the infarct sizes were measured with 2,3,5 triphenyltetrazolium chloride staining. Nuclear magnetic resonance was used to measure intracellular pH, Na+, and Ca2+. RESULTS:Left ventricular developed pressure, left ventricular end diastolic pressure, left ventricular dp/dtmax and dp/dtmin were significantly improved in the treatment groups when compared with those in the controls. Myocardial infarct size (24% ± 7%, 16% ± 8%, and 22% ± 7% in preconditioning, postconditioning, and pre-plus postconditioning groups versus 44% ± 8% in the control group, P < 0.05) and intracellular Na+ and Ca2+ were significantly decreased in all experimental groups at the end of reperfusion when compared with those in control. However, there were no differences between these variables in each treatment group. CONCLUSION:Sevoflurane postconditioning is as effective as preconditioning in protecting myocardial function after global ischemia. The combination of sevoflurane preconditioning and postconditioning offered no additional benefit over either intervention alone.

Comparison of postoperative hepatic function after laparoscopic versus open gastric bypass

BACKGROUND Pneumoperitoneum has been shown to reduce hepatic portal blood flow and alter postoperative hepatic transaminases. This study evaluated the changes in hepatic function after laparoscopic and open gastric bypass (GBP). METHODS Thirty-six morbidly obese patients were randomly assigned to undergo either laparoscopic (n = 18) or open (n = 18) GBP. Liver function tests--total bilirubin (T Bil), gamma GT (GGT), albumin, alkaline phosphatase (ALP), aspartate transferase (AST), alanine transferase (ALT)--and creatine kinase levels were obtained preoperatively and at 1, 24, 48, and 72 hours postoperatively. RESULTS The two groups were similar in age, sex, and body mass index. Albumin and ALP levels decreased while T Bil and GGT levels remained unchanged from baseline in both groups without significant difference between the two groups. After laparoscopic GBP, ALT and AST transiently increased by sixfold and returned to near baseline levels at 72 hours. After open GBP, ALT and AST transiently increased by fivefold to eightfold and returned to near baseline levels by 72 hours. Creatine kinase level was significantly lower after laparoscopic GBP than after open GBP at 48 and 72 hours postoperatively. There was no postoperative liver failure or mortality in either group. CONCLUSIONS Laparoscopic GBP resulted in transient postoperative elevation of hepatic transaminase (ALT, AST) but did not adversely alter hepatic function to any greater extent than open GBP. Creatine kinase levels were lower after laparoscopic GBP reflecting its lesser degree of abdominal wall trauma.

Cardiac function during laparoscopic vs open gastric bypass

BACKGROUND Hypercarbia and increased intraabdominal pressure during prolonged pneumoperitoneum can adversely affect cardiac function. This study compared the intraoperative hemodynamics of morbidly obese patients during laparoscopic and open gastric bypass (GBP). METHODS Fifty-one patients with a body mass index (BMI) of 40-60 kg/m2 were randomly allocated to undergo laparoscopic (n = 25) or open (n = 26) GBP. Cardiac output (CO), mean pulmonary artery pressure (MPAP), pulmonary artery wedge pressure (PAWP), central venous pressure (CVP), heart rate (HR), and mean arterial pressure (MAP) were recorded at baseline, intraoperatively at 30-min intervals, and in the recovery room. Systemic vascular resistance (SVR) and stroke volume (SV) were also calculated. RESULTS The two groups were similar in terms of age, weight, and BMI. Operative time was longer in the laparoscopic than in the open group (p < 0.05). The HR and MAP increased significantly from baseline intraoperatively, but there was no significant difference between the two groups. In the laparoscopic group, CO was unchanged after insufflation, but it increased by 5.3% at 2.5 h compared to baseline and by 43% compared to baseline in the recovery room. In contrast, during open GBP, CO increased significantly by 25% after surgical incision and remained elevated throughout the operation. CO was higher during open GBP than during laparoscopic GBP at 0.5 h and at 1 h after surgical incision (p < 0.05). During laparoscopic GBP, CVP, MPAP, and SVR increased transiently and PAWP remained unchanged. During open GBP, CVP, MPAP, and PAWP decreased transiently and SVR remained unchanged. There was no significant difference in the amount of intraoperative fluid administered during laparoscopic (5.5 +/- 1.6 L) and open (5.6 +/- 1.7 L) GBP. CONCLUSION Prolonged pneumoperitoneum during laparoscopic gastric bypass does not impair cardiac function and is well tolerated by morbidly obese patients.

Effects of pneumoperitoneum on intraoperative pulmonary mechanics and gas exchange during laparoscopic gastric bypass

Background: Hypercarbia and elevated intraabdominal pressure resulting from carbon dioxide (CO2) pneumoperitoneum can adversely affect respiratory mechanics. This study examined the changes in mechanical ventilation, CO2 homeostasis, and pulmonary gas exchange in morbidly obese patients undergoing a laparoscopic or open gastric bypass (GBP) procedure. Methods: In this study, 58 patients with a body mass index (BMI) of 40 to 60 kg/m2 were randomly allocated to laparoscopic (n = 31) or open (n = 27) GBP. Minute ventilation was adjusted to maintain a low normal arterial partial pressure of CO2 (PaCO2), low normal end-tidal partial pressure of CO2 (ETCO2), and low airway pressure. Respiratory compliance, ETCO2, peak inspiratory pressure (PIP), total exhaled CO2 per minute (VCO2), and pulse oximetry (SO2) were measured at 30-min intervals. The acid–base balance was determined by arterial blood gas analysis at 1-h intervals. The pulmonary gas exchange was evaluated by calculation of the alveolar dead space–to–tidal volume ratio (VDalv/VT) and alveolar–arterial oxygen gradient (PAO2–PaO2). Results: The two groups were similar in age, gender, and BMI. As compared with open GBP, laparoscopic GBP resulted in higher ETCO2, PIP, and VCO2, and a lower respiratory compliance. Arterial blood gas analysis demonstrated higher PaCO2 and lower pH during laparoscopic GBP than during open GBP (p < 0.05). The VDalv/VT ratio and PAO2–PaO2 gradient did not change significantly during laparoscopic GBP. Intraoperative oxygen desaturation (SO2 < 90%) did not develop in any of the patients in either group. Conclusions: Laparoscopic GBP alters intraoperative pulmonary mechanics and acid–base balance but does not significantly affect pulmonary oxygen exchange. Changes in pulmonary mechanics are well tolerated in morbidly obese patients when proper ventilator adjustments are maintained.

Effect of heated and humidified carbon dioxide gas on core temperature and postoperative pain: a randomized trial.

Background: Intraoperative hypothermia is a common event during laparoscopic operations. An external warming blanket has been shown to be effective in preventing hypothermia. It has now been proposed that using heated and humidified insufflation gas can prevent hypothermia and decrease postoperative pain. Therefore, we examined the extent of intraoperative hypothermia in patients undergoing laparoscopic Nissen fundoplication using an upper body warming blanket. We also attempted to determine whether using heated and humidified insufflation gas in addition to an external warming blanket would help to maintain intraoperative core temperature or decrease postoperative pain. Methods: Twenty patients were randomized to receive either standard carbon dioxide (CO2) gas (control, n = 10) or heated and humidified gas (heated and humidified, n = 10). After the induction of anesthesia, an external warming blanket was placed on all patients in both groups. Intraoperative core temperature and intraabdominal temperature were measured at 15-min intervals. Postoperative pain intensity was assessed using a visual analogue pain scale, and the amount of analgesic consumption was recorded. Volume of gas delivered, number of lens-fogging episodes, intraoperative urine output, and hemodynamic data were also recorded. Results: There was no significant difference between the two groups in age, length of operation, or volume of CO2 gas delivered. Compared with baseline value, mean core temperature increased by 0.4°C in the heated and humidified group and by 0.3°C in the control group at 1.5 h after surgical incision. Intraabdominal temperature increased by 0.2°C in the heated and humidified group but decreased by 0.5°C in the control group at 1.5 h after abdominal insufflation. There was no significant difference between the two groups in visual analog pain scale (5.4 ± 1.6 control vs 4.5 ± 2.8 heated and humidified), morphine consumed (27 ± 26 mg control vs 32 ± 19 mg heated and humidified), urine output, lens-fogging episodes, or hemodynamic parameters. Conclusion: Heated and humidified gas, when used in addition to an external warming blanket, minimized the reduction of intraabdominal temperature but did not alter core temperature or reduce postoperative pain.

Evaluation of Core Temperature during Laparoscopic and Open Gastric Bypass

Background: Intraoperative hypothermia is a common event during open and laparoscopic abdominal surgery. The aim of this study was to compare changes in core temperature between laparoscopic and open gastric bypass (GBP). Methods: 101 patients with a body mass index (BMI) of 40-60 kg/m2 were randomly assigned to open (n=50) or laparoscopic (n=51) GBP. Anesthetic technique was similar for both groups. An external warming blanket and passive airway humidification were used intraoperatively. Core temperature was recorded at preanesthesia, at baseline (after induction) and at 30-min intervals; intra-abdominal temperature was additionally measured at 30-min intervals in a subset of 30 laparoscopic GBP patients.The number of patients who developed intraoperative and postoperative hypothermia (<36°C) was recorded. Length of operation for both groups and the amount of CO2 gas delivered during laparoscopic operations were also recorded. Results: There was no significant difference between groups with respect to age, gender, mean BMI, and amount of intravenous fluid administered. After induction of anesthesia, core temperature significantly decreased in both groups; 36% of patients in the open group and 37% of patients in the laparoscopic group developed hypothermia. This percentage increased to 46% in the open group and 41% in the laparoscopic group during the operation, and then decreased to 6% in the open group and 8% in the laparoscopic group in the recovery-room. Core temperature increased during the operative procedure to reach 36.5 ± 0.6°Cin the open group and 36.3 ± 0.5°Cin the laparoscopic group at 2.5 hours after surgical incision. Intra-abdominal temperature during laparoscopic GBP was significantly lower than core temperature at all measurement points (p<0.05). Operative time was longer in the laparoscopic group than in the open group (232 ± 43 vs 201 ± 38 min, p<0.01). Mean volume of gas delivered during laparoscopic GBP was 650 ± 220 liters. Conclusion: Perioperative hypothermia was a common event during both laparoscopic and open GBP. Despite a longer operative time, laparoscopic GBP did not increase the rate of intraoperative hypothermia when efforts were made to minimize intraoperative heat loss.

Comparison of the Intubation Conditions Provided by Rapacuronium (ORG 9487) or Succinylcholine in Humans during Anesthesia with Fentanyl and Propofol

BACKGROUND Currently, the only approved muscle relaxant with a rapid onset and short duration of action is succinylcholine, a drug with some undesirable effects. Rapacuronium is an investigational nondepolarizing relaxant that also has a rapid onset and short duration and consequently should be compared with succinylcholine in its ability to facilitate rapid tracheal intubation. METHODS This prospective, randomized clinical trial involved 336 patients. Anesthesia was induced with fentanyl and propofol and either 1.5 mg/kg rapacuronium or 1.0 mg/kg succinylcholine. The goal was to accomplish tracheal intubation by 60 s after administration of the neuromuscular blocking drug. Endotracheal intubation was performed, and conditions were graded by a blinded investigator. Recovery of neuromuscular function was assessed by electromyography. RESULTS Intubation conditions were evaluated in 236 patients. Intubation by 60 s after drug administration occurred in 100% of patients with rapacuronium and in 98% with succinylcholine. Intubation conditions were excellent or good in 87% of patients with rapacuronium and in 95% with succinylcholine (P < 0.05). The time (median and range) to the first recovery of the train-of-four response was 8.0 (2.8-20.0) min with rapacuronium and 5.7 (1.8-17.7) min with succinylcholine (P < 0.05). The overall incidence of adverse effects was similar with both drugs. CONCLUSIONS A 1.5-mg/kg dose of rapacuronium effectively facilitates rapid tracheal intubation. It can be considered a valid alternative to 1.0 mg/kg succinylcholine for this purpose.