Gut permeability in paediatric cardiac surgery

Background. Intestinal mucosal ischaemia can occur in infantsand children during and after cardiac surgery. Severe decreasesin mucosal perfusion may cause complications such as necrotizingenterocolitis and postoperative mortality. We investigated gutpermeability in paediatric patients undergoing cardiac surgeryusing the dual sugar permeability test and absorption of twoother saccharides. Methods. Thirty-four patients undergoing palliative or correctivesurgical procedures with and without cardiopulmonary bypasswere investigated. Intestinal permeability was measured using3-O-methyl-D-glucose, D-xylose, L-rhamnose and lactulose, givenorally after induction of anaesthesia and 12 and 24 h later. Results. Lactulose/rhamnose ratios were raised from the outset[median 0.39 (confidence interval 0.07–1.8 for patientsundergoing operations without cardiopulmonary bypass and 0.30(0.02–2.6) with cardiopulmonary bypass]. The highest lactulose/rhamnoseratios were recorded 12 h after surgery 0.32 (0.07–6.9),when cardiopulmonary bypass was used. This is approximatelyseven times the value expected in healthy children. There wasan improvement in patients not undergoing cardiopulmonary bypass:0.22 (0.03–0.85) 12 h and 0.11 (0–0.48) 24 h afterinduction of anaesthesia. Patients undergoing repair of aorticcoarctation showed the fastest recovery: 0.09 (0.03–0.31)12 h and 0.07 (0.04–0.35) 24 h after induction of anaesthesia. Conclusions. Patients with congenital heart defects have abnormalgut permeability when compared with healthy children of similarage. Cardiopulmonary bypass seems to affect the intestinal barriermorphologically (lactulose and rhamnose absorption) and functionally(3-O-methyl-D-glucose and D-xylose absorption).     

Analgesic effect of intravenous dexamethasone after volar plate surgery for distal radius fracture with brachial plexus block anaesthesia: a prospective,double-blind randomised clinical trial*

Rebound pain after brachial plexus block resolution and development of long-lasting pain are problems associated with volar plate fixation for distal radius fractures. The aim of this double-blind study was to evaluate the effect of a single prophylactic intravenous dose of dexamethasone in this setting. The primary endpoint was highest pain score during the first 24 hours after surgery. We included 51 adults of ASA physical status 1–2 due to undergo planned acute fixation of the radius. All received premedication with oral paracetamol and etoricoxib, and a pre-operative brachial plexus block with ropivacaine. Patients were randomly allocated into two groups: a dexamethasone group receiving 16 mg dexamethasone intravenously at start of surgery and a control group receiving 4 ml saline. After surgery, all patients received fixed doses of paracetamol, etoricoxib and oxycodone, with further oxycodone added as needed in the first 48 hours. Pain, analgesic consumption and daily function were registered at predefined times up to 1 year after surgery. Median (IQR [range]) worst pain score in the first 24 hours, as assessed by verbal numeric rating scale (0–10), was 4 (2-6 [0–7]) in the dexamethasone group compared with 8 (5–8 [2–10]) in the placebo group (p < 0.001). Average pain score, 2 (1–4 [0–5]) vs. 5 (3–6 [0–8]), p = 0.001 and rescue oxycodone consumption, 5 (0-10 [0-35]) mg vs. 10 (5-15 [0-50]) mg, p = 0.037), respectively, were both significantly lower in the dexamethasone group compared with control from 8 to 24 hours. Brachial plexus block duration was 69% longer in the dexamethasone group, 21.5 (19.1-23.4 [12.9-24.1]) hours vs. 12.7 (11.9-15.3 [7.4-26.6]) hours, p < 0.001. Two patients (9%) in the dexamethasone group compared with 12 (50%) in the placebo group experienced worst pain scores of 8-10 during the first 36 hours (p = 0.002). At 3 and 7 days postoperatively, there were no significant differences between groups for pain scores or opioid consumption. At 6 months, 27 patients (57%) reported pain at the site of surgery, with significantly higher average pain score (p = 0.024) in the placebo group. At 1 year, two patients in the dexamethasone group reported pain compared with 10 in the placebo group (p = 0.015), and worst pain score was significantly higher in the placebo group (p = 0.018). We conclude that intravenous dexamethasone improves early postoperative analgesia and may also improve clinical outcomes after 6 and 12 months.     

Ketamine infusion reduces narcotic requirements following gastric bypass surgery: a randomized controlled trial

BackgroundAs the obesity epidemic worsens, anesthesiologists should expect to see more obese patients presenting for surgical procedures. Opioids cause respiratory depression, which has caused complications in patients with obstructive sleep apnea. Opioids can also cause nausea, prolonging the time that patients spend in the postanesthesia care unit. Ketamine is a potential analgesic alternative that may have advantages to narcotics in the bariatric population.ObjectivesTo determine whether an intraoperative ketamine infusion would reduce postoperative narcotic use in patients during the first 48 hours after laparoscopic gastric bypass.SettingMajor academic medical center.MethodsThere were 54 participating patients. The intervention group (n = 27) was randomized to receive 100 μg of fentanyl with anesthesia induction, then a 20-mg bolus of ketamine, followed by a 5 μg/kg/min intraoperative ketamine infusion starting after anesthesia induction and ending after wound closure commenced. The control group (narcotic only, n = 27) also received 100 μg of fentanyl at anesthesia induction and intraoperative boluses of fentanyl at the discretion of the anesthesia team, with .3 mg of hydromorphone administered approximately 45 minutes before the completion of surgery.ResultsAt 24 hours, the mean morphine-equivalent units (MEUs) were 12.7 (standard deviation [SD], 9.9; 95% confidence interval [CI], 8.8–16.6) for the ketamine group (n = 28) and 16.5 (SD, 9.8; 95% CI, 12.6–20.4) for the control group (n = 28). At 48 hours, the MEUs were 16.7 (SD, 12.0; 95% CI, 11.9–21.4) for the ketamine group and 22.7 (SD, 14.9; 95% CI, 16.8–28.6) for the control group. Cumulative MEUs for 24 hours (P = .039) and 48 hours (P = .058) postoperatively were lower in the ketamine group compared with the narcotic-only (control) group, although the difference at 48 hours did not reach statistical significance. Compared with the narcotic-only group, the ketamine group used 26% fewer MEUs after 24 hours and 31% fewer MEUs after 48 hours. This difference can mostly be attributed to group differences during the first 6 hours after surgery.ConclusionsKetamine successfully reduced the amount of opioids required to control bariatric patients’ pain at 24 hours postoperatively, but not over the 48-hour postoperative period.     

Effect of Nitrous Oxide Anesthesia on Plasma Homocysteine and Endothelial Function

Background: Endothelial function is impaired with hyperhomocysteinemia. Plasma homocysteine is increased by nitrous oxide anesthesia. The current study was designed to determine whether endothelial function is impaired after surgery and whether this is made worse by exposure to nitrous oxide.

Methods: The authors studied 59 patients with cardiovascular disease undergoing noncardiac surgery. Patients were randomly allocated to nitrous oxide-based anesthesia (n = 25) or nitrous oxide-free anesthesia (control, n = 34). Endothelial function was measured by flow-mediated dilation of the brachial artery before and 24 h after surgery. In addition, blood was drawn at both time points for the measurements of plasma homocysteine, folate, l-arginine, l-citrulline, asymmetric dimethylarginine, and nitrate concentrations.

Results: The median duration of general anesthesia was 4.5 h. Patients had significantly lower flow-mediated dilation after surgery (5.1 +/- 3.3 to 3.0 +/- 4.1%; P = 0.001). Duration of anesthesia affected endothelial function. In the nitrous oxide group, there was an inverse correlation with flow-mediated dilation (r = -0.60, P = 0.004), but in the control group, there was a positive correlation (r = 0.61, P < 0.001). When compared with control, nitrous oxide exposure was associated with a significant increase in postoperative homocysteine (mean difference, 4.9 [mu]m; 95% confidence interval, 2.8-7.0 [mu]m; P < 0.0005) and decrease in flow-mediated dilation (3.2%; 95% confidence interval, 0.1-5.3%; P = 0.001). Nitrous oxide exposure was not associated with change in nitric oxide substrates.     

经皮穴位电刺激对全麻手术术后镇痛效果影响的Meta分析

目的 评价麻醉诱导前进行经皮穴位电刺激（TEAS）对全麻手术术后镇痛效果的影响。
方法 检索ScienceDirect、Pubmed、Cochrane library、Web of Science、Embase、知网、万方、维普、中国生物医学数据库等数据库,检索时间为建库至2021年11月。收集麻醉诱导前采用TEAS用于术后辅助镇痛的随机对照试验（RCT）。RevMan 5.3软件进行Meta分析。
结果 共纳入10篇文献,820例患者,其中TEAS组409例,对照组411例。Meta分析显示,TEAS组术后4、12、24、48 h VAS疼痛评分明显低于对照组（术后4 h,MD=-1.45分,95%CI -2.69～-0.20,P=0.02;术后12 h,MD=-0.50分,95%CI -0.98～-0.02,P=0.04;术后24 h,MD=-0.75分,95%CI -1.10～-0.40,P<0.01;术后48 h,MD=0.38分,95%CI -0.74～-0.02,P=0.04）,术后恶心呕吐发生率明显低于对照组（OR=0.35,95%CI 0.24～0.51,P<0.01）,两组术中阿片类药物用量差异无统计学意义。
结论 麻醉诱导前应用经皮穴位电刺激可显著提高术后镇痛的效果,降低术后不良反应发生率。     

Predictors of long-term mortality and cardiac events in patients with known or suspected coronary artery disease who survive major non-cardiac surgery

The aim of this prospective study was to assess predictors of long-term outcome in patients with documented or suspected coronary artery disease who survive major non-cardiac surgery. The impact of patients' comorbidities, pre-operative heart rate variability and postoperative increase in cardiac troponin I on all-cause mortality and major cardiac events within 2 years was explored using multivariable logistic regression. Six of 173 patients died within the first month after surgery and were excluded from the study. Thirty-four of 167 patients (20%) died 1-24 months after surgery. Independent predictors of all-cause mortality were history of congestive heart failure (odds ratio 6.4 [95%, confidence interval 1.7-24]), pre-operatively depressed heart rate variability (odds ratio 6.4 [95%, confidence interval 1.9-21]), and age > 70 years (odds ratio 4.5 [95%, confidence interval 1.2-16]). In contrast, postoperative elevation of cardiac troponin I did not independently predict all-cause mortality or major cardiac events.     

A randomized trial comparing induction chemotherapy followed by surgery with surgery alone for patients with stage IIIA N2 non-small cell lung cancer (JCOG 9209)

OBJECTIVE: We performed a prospective randomized trial in patients with potentially resectable stage IIIA N2 non-small cell lung cancer to confirm the efficacy of induction chemotherapy before surgical resection. METHODS: Patients with stage IIIA N2 non-small cell lung cancer, all with histologically or cytologically confirmed metastases to the ipsilateral mediastinal lymph nodes, were randomly assigned to receive either three cycles of induction chemotherapy (cisplatin at 80 mg/m(2) on 1 day and vindesine at 3 mg/m(2) on 2 days) followed by surgery or surgery alone. RESULTS: This trial was prematurely terminated because the accrual rate was too slow, which lowered the study's statistical power considerably. From June 1993 through April 1998, a total of 62 patients were enrolled, and 31 patients were assigned to each treatment group. The objective clinical response rate of induction chemotherapy was 28%. Complete resection was achieved in 20 patients in the induction chemotherapy group (65%) and 24 in the surgery alone group (77%). Median follow-up was 6.2 years. Median overall survivals were 17 months for the induction group and 16 months for the surgery alone group. The estimated 1-, 3-, and 5-year survivals, respectively, were 68% (95% confidence interval 51%-85%), 23% (95% confidence interval 8%-38%), and 10% (95% confidence interval 0%-20%) for the induction chemotherapy group and 65% (95% confidence interval 48%-82%), 26% (95% confidence interval 11%-41%), and 22% (95% confidence interval 7%-37%) for the surgery alone group. There was no statistically significant difference in survival between the groups (P =.5274). Treatment-related death was not observed in either group. CONCLUSION: This randomized trial to compare induction chemotherapy (cisplatin and vindesine) followed by surgery with surgery alone for patients with stage IIIA N2 non-small cell lung cancer did not demonstrate a survival difference between the groups, although this may have been because the statistical power was limited.     

A comparison of three antiemetic combinations for the prevention of postoperative nausea and vomiting

In this study we compared the efficacy and safety of three antiemetic combinations in the prevention of postoperative nausea and vomiting (PONV). Ninety ASA status I-II women, aged 18-65 yr, undergoing general anesthesia for major gynecological surgery, were included in a prospective, randomized, double-blinded study. A standardized anesthetic technique and postoperative analgesia (intrathecal morphine plus IV patient-controlled analgesia (PCA) with morphine) were used in all patients. Patients were randomly assigned to receive ondansetron 4 mg plus droperidol 1.25 mg after the induction of anesthesia and droperidol 1.25 mg 12 h later (Group 1, n = 30), dexamethasone 8 mg plus droperidol 1.25 mg after the induction of anesthesia and droperidol 1.25 mg 12 h later (Group 2, n = 30), or ondansetron 4 mg plus dexamethasone 8 mg after the induction of anesthesia and placebo 12 h later (Group 3, n = 30). A complete response, defined as no PONV in 48 h, occurred in 80% of patients in Group 1, 70% in Group 3, and 40% in Group 2 (P = 0.004 versus Groups 1 and 3). The incidences of side effects and other variables that could modify the incidence of PONV were similar among groups. In conclusion, ondansetron, in combination with droperidol or dexamethasone, is more effective than dexamethasone in combination with droperidol in women undergoing general anesthesia for major gynecological surgery with intrathecal morphine plus IV PCA with morphine for postoperative analgesia. IMPLICATIONS: The combination of ondansetron plus dexamethasone or droperidol was significantly better than the combination of dexamethasone plus droperidol in the prophylaxis of postoperative nausea and vomiting in women undergoing general anesthesia for major gynecological surgery, with intrathecal and IV morphine (patient-controlled analgesia) for management of postoperative pain.     

Perspectives on transdermal scopolamine for the treatment of postoperative nausea and vomiting

Transdermal scopolamine, a patch system that delivers 1.5 mg of scopolamine gradually over 72 hours following an initial bolus, was approved in the United States in 2001 for the prevention of postoperative nausea and vomiting (PONV) in adults. Scopolamine (hyoscine) is a selective competitive anatagonist of muscarinic cholinergic receptors. Low serum concentrations of scopolamine produce an antiemetic effect. Transdermal scopolamine is effective in preventing PONV versus placebo [relative risk (RR)=0.77, 95% confidence interval (CI), 0.61-0.98, P = 0.03] and a significantly reduced risk for postoperative nausea (RR=0.59, 95% CI, 0.48-0.73, P < 0.001), postoperative vomiting (RR=0.68, 95% CI, 0.61-0.76, P < 0.001), and PONV (RR 0.73, 95% CI, 0.60-0.88, P = 001) in the first 24 hours after the start of anesthesia.     

Combined intrathecal and epidural magnesium sulfate supplementation of spinal anesthesia to reduce post-operative analgesic requirements: a prospective, randomized, double-blind, controlled trial in patients undergoing major orthopedic surgery

BACKGROUND: New ways of decreasing post-operative analgesic drug requirements are of special interest after major surgery. Magnesium sulfate (MgSO(4)) alters pain processing and reduces the induction and maintenance of central sensitization by blocking the N-methyl-D-aspartate (NMDA) receptor in the spinal cord. We investigated whether supplementation of spinal anesthesia with combined intrathecally and epidurally infused MgSO(4) reduced patients' post-operative analgesia requirements. METHODS: In a randomized, prospective, double-blind, placebo-controlled trial, we enrolled 120 consecutive patients undergoing orthopedic surgery during spinal anesthesia (levobupivacaine and sufentanil). Patients were randomly assigned to receive intrathecal MgSO(4) (94.5 mg, 6.3%), epidural MgSO(4) (2%, 100 mg/h), intrathecal and epidural MgSO(4) combined or spinal anesthesia alone (controls). Post-operative morphine consumption was assessed in all groups by patient-controlled analgesia (PCA). RESULTS: Of the 120 patients enrolled, 103 (86%) completed the study. Morphine consumption at 36 h after surgery was 38% lower in patients receiving spinal anesthesia plus epidural MgSO(4) [- 14.963 mg; 95% confidence interval (CI), - 1.44 to - 28.49 mg], 49% lower in those receiving spinal anesthesia plus intrathecal MgSO(4) (- 18.963 mg; 95% CI, - 5.27 to - 32.65 mg) and 69% lower in the intrathecal-epidural combined group (- 26.963 mg; 95% CI, - 13.73 to - 40.19 mg) relative to control patients receiving spinal anesthesia alone. No complications developed during the post-operative course or at 1 month after surgery. CONCLUSION: In patients undergoing orthopedic surgery, supplementation of spinal anesthesia with combined intrathecal and epidural MgSO(4) significantly reduces patients' post-operative analgesic requirements.     

A comparison of the roles of cefamandole and ceftriaxone in abdominal surgery

In a prospective, randomized study, we compared the ability of ceftriaxone sodium (serum half-life, 8.0 hours) and cefamandole naftate and sodium carbonate (serum half-life, 0.8 hours) to prevent wound infection in 1238 patients undergoing abdominal surgery. Prophylaxis consisted of single-dose therapy at the time of induction of anesthesia, and treatment regimens contained ceftriaxone sodium, 1 g/d intravenously, or cefamandole naftate and sodium carbonate, 1 g intravenously every 6 hours. Except for low-risk biliary procedures, cephalosporin therapy was accompanied by the administration of metronidazole. No significant difference was noted in the incidence of wound infection, ie, 5.6% for the ceftriaxone group (95% confidence interval, 3.8% to 7.4%) and 6.9% for the cefamandole group (95% confidence interval, 4.9% to 8.9%). Single-dose prophylaxis with 1 g of cefamandole naftate and sodium carbonate was relatively inexpensive and provided a cost savings of 64%. When treatment was required, a 23% cost savings was associated with the use of a once-daily dose of 1 g of ceftriaxone sodium.     

Impact of anesthesia management characteristics on severe morbidity and mortality

BACKGROUND: Quantitative estimates of how anesthesia management impacts perioperative morbidity and mortality are limited. The authors performed a study to identify risk factors related to anesthesia management for 24-h postoperative severe morbidity and mortality. METHODS: A case-control study was performed of all patients undergoing anesthesia (1995-1997). Cases were patients who either remained comatose or died during or within 24 h of undergoing anesthesia. Controls were patients who neither remained comatose nor died during or within 24 hours of undergoing anesthesia. Data were collected by means of a questionnaire, the anesthesia and recovery form. Odds ratios were calculated for risk factors, adjusted for confounders. RESULTS: The cohort comprised 869,483 patients; 807 cases and 883 controls were analyzed. The incidence of 24-h postoperative death was 8.8 (95% confidence interval, 8.2-9.5) per 10,000 anesthetics. The incidence of coma was 0.5 (95% confidence interval, 0.3-0.6). Anesthesia management factors that were statistically significantly associated with a decreased risk were: equipment check with protocol and checklist (odds ratio, 0.64), documentation of the equipment check (odds ratio, 0.61), a directly available anesthesiologist (odds ratio, 0.46), no change of anesthesiologist during anesthesia (odds ratio, 0.44), presence of a full-time working anesthetic nurse (odds ratio, 0.41), two persons present at emergence (odds ratio, 0.69), reversal of anesthesia (for muscle relaxants and the combination of muscle relaxants and opiates; odds ratios, 0.10 and 0.29, respectively), and postoperative pain medication as opposed to no pain medication, particularly if administered epidurally or intramuscularly as opposed to intravenously. CONCLUSIONS: Mortality after surgery is substantial and an association was established between perioperative coma and death and anesthesia management factors like intraoperative presence of anesthesia personnel, administration of drugs intraoperatively and postoperatively, and characteristics of delivered intraoperative and postoperative anesthetic care.     

Outcome study of psychological distress and nonspecific symptoms in patients with mild primary hyperparathyroidism

BACKGROUND: Primary hyperparathyroidism is a common endocrinopathy. The appropriate management of its mild form, however, remains controversial. HYPOTHESIS: Mild primary hyperparathyroidism is associated with psychological distress and other nonspecific symptoms that improve following parathyroidectomy. DESIGN: Two-year prospective before-after study. SETTING: University hospital. PATIENTS: Twenty-six consecutive patients with mild hypercalcemia (<12 mg/dL [<3 mmol/L]) due to primary hyperparathyroidism, without osteitis fibrosa cystica or urolithiasis were enrolled from January 11, 1997, through April 21, 1998. INTERVENTION: Parathyroidectomy. MAIN OUTCOME MEASURES: Primary outcome was psychological distress as measured by the 28-item version of the General Health Questionnaire. Secondary outcomes included body weight, joint pain, and occurrences of bowel movements and urination. RESULTS: Before surgery, 15 patients (58%; 95% confidence interval, 37%-77%) showed psychological distress (case group) while 11 patients did not (noncase group). A clinically and statistically significant reduction in the General Health Questionnaire score was detected at 3 months in the case group (-6.1; 95% confidence interval, -11.0 to -1.2), but the reduction was smaller (-1.9; 95% confidence interval, -6.9 to 3.0) at 24 months after surgery. No significant change in the General Health Questionnaire score was observed in the noncase group during the follow-up. No significant change was noted in any of the secondary outcomes. CONCLUSIONS: Psychological distress was associated with mild primary hyperparathyroidism and was ameliorated after surgery. The improvement, however, was limited in extent and duration.     

Caudal anesthesia reduces the minimum alveolar concentration of enflurane for laryngeal mask airway removal in boys

PURPOSE: To investigate the effects of caudal analgesia on the minimal alveolar concentration of enflurane for laryngeal mask airway (LMA) smooth extubation (MACex). METHODS: We studied 50 nonpremedicated children, aged three to ten years, ASA physical status I, undergoing surgery for hypospadias repair. After a sevoflurane inhalation induction, children were randomized to receive LMA insertion with or without ropivacaine caudal analgesia. At the end of surgery, a predetermined end-tidal enflurane concentration was achieved, and the LMA was removed by an anesthesiologist blinded to group allocation. Each concentration at which LMA extubation was attempted was predetermined by the up-and-down method (with 0.1% as the step size). When LMA removal was accomplished without coughing, clenching teeth or gross purposeful muscular movements during or within one minute after removal, it was considered successful. RESULTS: MACex of enflurane for LMA removal in the group without caudal anesthesia was 1.04% (95% confidence interval, 1.00-1.10) and the LMA MACex of enflurane in the group with caudal anesthesia was 0.74% (95% confidence interval, 0.63-0.81). Caudal analgesia significantly reduced enflurane requirements by 29% (95% confidence interval, 22-36%). CONCLUSION: In conclusion, caudal analgesia significantly reduced the LMA MACex of enflurane by approximately 29%. Possible mechanisms may be related to the analgesic effect of caudal blockade or to the sedative properties of neuraxial anesthesia.     

Risk factors for perioperative myocardial ischemia in carotid artery endarterectomy

OBJECTIVE: To identify variables associated with perioperative myocardial ischemia in patients undergoing carotid artery endarterectomy (CEA). DESIGN: Prospective, observational study. SETTING: University-affiliated hospital operating room and intensive care unit. PARTICIPANTS: One hundred twenty-eight consecutive patients who underwent CEA during a 7-year period. INTERVENTIONS: Patients had general anesthesia with sevoflurane or isoflurane. CEA was performed by standard methods with shunting if clinically indicated. Holter electrocardiogram (ECG) monitoring was performed during surgery and 24 hours after surgery. MEASUREMENTS AND MAIN RESULTS: The incidence of perioperative myocardial ischemia was examined, and perioperative risk factors were analyzed. Nineteen patients (15%) showed significant perioperative ECG abnormalities indicative of myocardial ischemia (10 patients during surgery, 12 patients after surgery, and 3 patients both during and after surgery). Multivariate analysis showed perioperative myocardial ischemia to be significantly associated with a history of angina (odds ratio, 11.68; 95% confidence interval, 2.64-51.70) and a history of hypertension (odds ratio, 14.08; 95% confidence interval, 1.51-131.04). CONCLUSION: The data indicate that perioperative myocardial ischemia defined as an ECG abnormality does not often occur in patients undergoing CEA. However, angina and hypertension may be important risk factors warranting further investigation.     

Thoracoabdominal aneurysm repair: perspectives over a decade with the clamp-and-sew technique.

OBJECTIVES: Experience over a decade with thoracoabdominal aortic aneurysm (TAA) repair using a clamp-sew technique was reviewed to compare overall results with alternative operative methods. SUMMARY BACKGROUND DATA: Controversy continues as to the optimal technique for TAA repair, with frequent contemporary emphasis on bypass-distal perfusion methods. Proponents of this technique claim improved results compared to those of historic control subjects in the parameters of operative mortality, postoperative renal failure, and lower extremity neurologic deficit. METHODS: Over the interval from 1987 to 1996, 160 TAA repairs (type I, 32%; type II, 15%; type III, 34%; and type IV, 19%) were performed in 157 patients with a mean age of 70 years and a male-to-female ratio of 1/1. Clinical features included ruptured TAA (10%), urgent operation (22.5%), and aortic dissection (18%). Operative management used a clamp-sew technique with regional hypothermia for spinal cord (epidural cooling, since 1993) and renal protection. Variables associated with the endpoints of operative mortality or major morbidity, particularly spinal cord injury, were assessed with Fisher exact test and logistic regression; late survival was estimated with the Kaplan-Meier method. RESULTS: In-hospital mortality was 9% and was associated with operation for rupture (p < 0.005) or other acute presentation (p < 0.001). After multivariate analysis, the postoperative complication renal failure (relative risk, 6.5 [95% confidence interval, 1.8-23.6, p = 0.004]) and significant spinal cord injury (relative risk, 16.5 [95% confidence interval, 3.2-83.2, p = 0.001]) were associated independently with operative mortality. Paraparesis-paraplegia occurred in 7%, an incidence significantly (p < 0.001) less than that (18.7%) predicted for this cohort from published models. Variables associated (univariate analysis) with this complication included TAA rupture (p < 0.0001), other acute presentation or dissection (p < 0.001), prolonged (>6 hours) operation (p < 0.04), and excessive (>3 L) transfusions (p < 0.02). Operation for acute presentation or dissection (relative risk, 7.9 [95% confidence interval, 1.7-37.7, p = 0.009]) and prolonged surgery [relative risk, 7.5 [95% confidence interval, 1.5-35.3, p = 0.01]) retained independent association with paraplegia-paraparesis after multivariate analysis. Dialysis was needed in 2.5%. Late survival at 1 and 5 years was 86 +/- 2.9% and 62 +/- 5.8%, respectively. CONCLUSIONS: These data compare favorably with those from contemporary reports using other operative strategies and do not support routine adoption of bypass-distal perfusion as the preferred technique for TAA repair.     

Resuscitation-induced gut edema and intestinal dysfunction

BACKGROUND: Mesenteric venous hypertension and subsequent gut edema play a pivotal role in the development of intra-abdominal hypertension. Although gut edema is one cause of intra-abdominal hypertension, its impact on gut function is unknown. The purpose of this study was to create a model of acute hydrostatic gut edema and to evaluate its effect on gut motility and barrier function. METHODS: The first study, group A, evaluated the effect of gut edema on transit over time using 20 mL/kg 0.9% saline. The second study, group B, focused on the 12-hour time period using 80 mL/kg 0.9% saline. Rats were randomized to superior mesenteric vein partial occlusion (venous hypertension) or sham surgery. At 6, 12, and 24 hours, group A underwent intestinal transit and tissue water weight measurements. At 12 hours, group B underwent tissue water, transit, ileal permeability and resistance, lactate and myeloperoxidase activity, and mucosal injury measurements. RESULTS: Venous hypertension with fluid resuscitation caused acute hydrostatic gut edema, delayed intestinal transit, increased mucosal permeability to macromolecules, and decreased tissue resistance over time. Mucosal injury was minimal in mesenteric venous hypertension. CONCLUSION: Acute mesenteric venous hypertension and resuscitation-induced gut edema, in the absence of ischemia/reperfusion injury, is associated with delayed intestinal transit and altered gut barrier function.     

Predictors of unanticipated admission following ambulatory surgery: a retrospective case-control study

Purpose

The primary objectives of this historical case-control study were to evaluate the incidence of and reasons and risk factors for adult unanticipated admissions in three tertiary care Canadian hospitals following ambulatory surgery.

Methods

A random sample of 200 patients requiring admission (cases) and 200 patients not requiring admission (controls) was taken from 20,657 ambulatory procedures was identified and compared. The following variables were included: demographics, reason for admission, type of anesthesia, surgical procedure, length of procedure, American Society of Anesthesiologists’ (ASA) classification, surgical completion time, pre-anesthesia clinic, medical history, medications (classes), and perioperative complications. Multiple logistic regression analysis was used to assess factors associated with unanticipated admissions.

Results

The incidence of unanticipated admission following ambulatory surgery was 2.67%. The most common reasons for admission were surgical (40%), anesthetic (20%), and medical (19%). The following factors were found to be associated with an increased risk of unanticipated admission: length of surgery of one to three hours (odds ratio [OR] 16.70; 95% confidence interval [CI] 4.10 to 67.99) and length of surgery more than three hours (OR 4.26; 95% CI 2.40 to 7.55); ASA class III (OR 4.60; 95% CI 1.81 to 11.68); ASA class IV (OR 6.51; 95% CI 1.66 to 25.59); advanced age (> 80 yr) (OR 5.41; 95% CI 1.54 to 19.01); and body mass index (BMI) of 30-35 (OR 2.81; 95% CI 1.31 to 6.04). Current smoking status was found to be associated with a decreased likelihood of unanticipated admission (OR 0.44; 95% CI 0.23 to 0.83), as was monitored anesthesia care when compared with general anesthesia (OR 0.17; 95% CI 0.04 to 0.68) and plastic (OR 0.18; 95% CI 0.07 to 0.50), orthopedic (OR 0.16; 95% CI 0.08 to 0.33), and dental/ear-nose-throat surgery (OR 0.32; 95% CI 0.13 to 0.83) when compared with general surgery. Other comorbid conditions did not impact unanticipated admission.

Conclusion

Unanticipated admission after ambulatory surgery occurs mainly due to surgical, anesthetic, and medical complications. Length of surgery more than one hour, high ASA class, advanced age, and increased BMI were all predictors. No specific comorbid illness was associated with an increased likelihood of unanticipated admission. These findings support continued use of the ASA classification as a marker of patient perioperative risk rather than attributing risk to a specific disease process.     

Continuous monitoring of cerebral oxygen saturation in elderly patients undergoing major abdominal surgery minimizes brain exposure to potential hypoxia

Elderly patients are more prone than younger patients to develop cerebral desaturation because of the reduced physiologic reserve that accompanies aging. To evaluate whether monitoring cerebral oxygen saturation (rSO(2)) minimizes intraoperative cerebral desaturation, we prospectively monitored rSO(2) in 122 elderly patients undergoing major abdominal surgery with general anesthesia. Patients were randomly allocated to an intervention group (the monitor was visible and rSO(2) was maintained at > or =75% of preinduction values; n = 56) or a control group (the monitor was blinded and anesthesia was managed routinely; n = 66). Cerebral desaturation (rSO(2) reduction <75% of baseline) was observed in 11 patients of the treatment group (20%) and 15 patients of the control group (23%) (P = 0.82). Mean (95% confidence intervals) values of mean rSO(2) were higher (66% [64%-68%]) and the area under the curve below 75% of baseline (AUCrSO2(2)< 75% of baseline) was lower (0.4 min% [0.1-0.8 min%]) in patients of the treatment group than in patients of the control group (61% [59%-63%] and 80 min% [2-144 min%], respectively; P = 0.002 and P = 0.017). When considering only patients developing intraoperative cerebral desaturation, a lower Mini Mental State Elimination (MMSE) score was observed at the seventh postoperative day in the control group (26 [25-30]) than in the treatment group (28 [26-30]) (P = 0.02), with a significant correlation between the AUCrSO(2) < 75% of baseline and postoperative decrease in MMSE score from preoperative values (r(2)= 0.25, P = 0.01). Patients of the control group with intraoperative cerebral desaturation also experienced a longer time to postanesthesia care unit (PACU) discharge (47 min [13-56 min]) and longer hospital stay (24 days [7-53] days) compared with patients of the treatment group (25 min [15-35 min] and 10 days [7-23 days], respectively; P = 0.01 and P = 0.007). Using rSO(2) monitoring to manage anesthesia in elderly patients undergoing major abdominal surgery reduces the potential exposure of the brain to hypoxia; this might be associated with decreased effects on cognitive function and shorter PACU and hospital stay.