Inter-Rater Agreement of the Classification of Intraoperative Adverse Events (ClassIntra) in Abdominal Surgery.

OBJECTIVE AND SUMMARY OF BACKGROUND DATA: Adverse events in surgical patients can occur preoperatively, intraoperatively, and postoperatively. Universally accepted classification systems are not yet available for intraoperative adverse events (iAEs). ClassIntra has recently been developed and validated as a tool for grading iAEs that occur between skin incision and skin closure irrespective of the origin, that is, surgery, anesthesia, or organizational. The aim of this study is to assess the inter-rater agreement of ClassIntra and assess its predictive value for postoperative complications in elective abdominal surgery. METHODS: This study is a secondary use of data from the LAParotomy or LAParoscopy and ADhesiolysis (LAPAD) study, with detailed data on incidence and management of intra-operative and post-operative complications. Data were collected in a cohort of elective abdominal surgeries. Two teams graded all recorded events in the LAPAD study according to ClassIntra. Cohen Kappa coefficient was calculated to determine inter-rater agreement. Uni- and multivariable linear regression was used to assess the predictive value of the ClassIntra grades for postoperative complications. RESULTS: IAEs were rated in 333 of 755 (44%) surgeries by team 1, and in 324 of 755 (43%) surgeries by team 2. Cohen kappa coefficient for ClassIntra grades was 0.87 [95% confidence interval (CI) 0.84-0.90]. Discrepancies in grading were most frequent for intraoperative bleeding and adhesions' associated injuries. At least 1 postoperative complication was observed in 278 (37%) patients. The risk of a postoperative complications increased with every increase in severity grade of ClassIntra. Intraoperative hypotension [mean difference (MD) 23.41, 95% CI 12.93-33.90] and other organ injuries (MD 18.90, 95% CI -4.22 - 42.02) were the strongest predictors for postoperative complications. CONCLUSIONS: ClassIntra has an almost perfect inter-rater agreement for the classification of iAEs. An increasing grade of ClassIntra was associated with a higher incidence of postoperative complications. Discrepancies in grading related to common complications in abdominal procedures mostly consisted of intraoperative bleeding and adhesion-related injuries. Grading of interoperative events in abdominal surgery might further improve by consensus regarding the definitions of a number of frequent events.

Generalisability of randomised trials of the programmed intermittent epidural bolus technique for maintenance of labour analgesia: a prospective single centre cohort study.

BACKGROUND: Several randomised controlled trials show that maintenance of labour epidural analgesia with programmed intermittent epidural bolus reduces the maternal motor block compared with maintenance with a continuous infusion. However, these trials were usually restricted to healthy nulliparous parturients. To assess the generalisability of these randomised controlled trials to 'real-world' conditions, we compared maternal motor function (modified Bromage score) over time between healthy nulliparous and parous women using routinely collected quality-control data. METHODS: After ethical approval, all parturients receiving programmed intermittent epidural bolus labour analgesia between June 2013 and October 2014 were included in this prospective cohort study. Bupivacaine 0.1% with fentanyl 2 µg ml-1 was used allowing for patient-controlled bolus every 20 min. The maternal motor function (primary outcome) was regularly assessed from insertion of the epidural catheter until delivery. RESULTS: Of the 839 parturients included, 553 (66%) were nulliparous and 286 (34%) were parous. The parous women had a shorter median duration of epidural analgesia (3 h 59 min vs 5 h 45 min) and a higher incidence of spontaneous delivery (66% vs 37%). The probability of being in a certain Bromage category at birth was similar in nulliparous and parous women in a general additive model adjusting for duration of epidural analgesia, number of rescue top-ups, and number of catheter manipulations (cumulative odds ratio: 1.18; 95% confidence interval: 0.98-1.41). Parous women required a higher time-weighted number and volume of rescue top-ups. CONCLUSIONS: The results of the randomised controlled trials on a reduced motor block with programmed intermittent epidural bolus seem generalisable to parturients typically not included in these trials.

Systematic review and simulation study of ignoring clustered data in surgical trials.

BACKGROUND: Multiple surgical procedures in a single patient are relatively common and lead to dependent (clustered) data. This dependency needs to be accounted for in study design and data analysis. A systematic review was performed to assess how clustered data were handled in inguinal hernia trials. The impact of ignoring clustered data was estimated using simulations. METHODS: PubMed, Embase and the Cochrane Library were reviewed systematically for RCTs published between 2004 and 2013, including patients undergoing unilateral or bilateral inguinal hernia repair. Study characteristics determining the appropriateness of handling clustered data were extracted. Using simulations, various statistical methods accounting for clustered data were compared with an analysis ignoring clustering by assuming 100 hernias, with a varying percentage of patients having bilateral hernias. RESULTS: Of the 50 eligible trials including patients with bilateral hernias, 20 (40 per cent) did not provide information on how they dealt with clustered data and 18 (36 per cent) avoided clustering by assessing the outcome by patient and not by hernia. None of the remaining 12 trials (24 per cent) considered clustering in the design or analysis. In the simulations, ignoring clustering led to an increased type I error rate of up to 12 per cent and to a loss in power of up to 15 per cent, depending on whether the patient or the hernia was the randomization unit. CONCLUSION: Clustering was rarely considered in inguinal hernia trials. The simulations underline the importance of considering clustering as part of the statistical analysis to avoid false-positive and false-negative results, and hence inappropriate study conclusions.

Efficacy and safety of carbetocin given as an intravenous bolus compared with short infusion for Caesarean section - double-blind, double-dummy, randomized controlled non-inferiority trial.

BACKGROUND: Carbetocin is a synthetic oxytocin-analogue, which should be administered as bolus according to manufacturer's recommendations. A higher speed of oxytocin administration leads to increased cardiovascular side-effects. It is unclear whether carbetocin administration as short infusion has the same efficacy on uterine tone compared with bolus administration and whether haemodynamic parameters differ. METHODS: In this randomized, double-blind, non-inferiority trial, women undergoing planned or unplanned Caesarean section (CS) under regional anaesthesia received a bolus and a short infusion, only one of which contained carbetocin 100 mcg (double dummy). Obstetricians quantified uterine tone two, three, five and 10 min after cord-clamping by manual palpation using a linear analogue scale from 0 to 100. We evaluated whether the lower limit of the 95% CI of the difference in maximum uterine tone within the first five min after cord-clamping did not include the pre-specified non-inferiority limit of -10. RESULTS: Between December 2014 and November 2015, 69 patients were randomized to receive carbetocin as bolus and 71 to receive it as short infusion. Maximal uterine tone was 89 in the bolus and 88 in the short infusion group (mean difference -1.3, 95% CI -5.7 to 3.1). Bp, calculated blood loss, use of additional uterotonics, and side-effects were comparable. CONCLUSIONS: Administration of carbetocin as short infusion does not compromise uterine tone and has similar cardiovascular side-effects as a slow i.v. bolus. In accordance with current recommendations for oxytocin, carbetocin can safely be administered as short -infusion during planned or unplanned CS. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT02221531 and www.kofam.ch SNCTP000001197.

Surgical treatment of uncomplicated diverticulitis in Switzerland: comparison of population-based data over two time periods.

AIM: The standard of care for acute uncomplicated diverticulitis used to be an elective colon resection after the second or third episode. This practice was replaced by a more conservative and individualized approach. This study investigates current surgical practice in the treatment of acute uncomplicated diverticulitis in Switzerland. METHOD: Retrospective cross-sectional analysis of all hospital admissions due to uncomplicated diverticulitis in Switzerland using prospectively collected data from the Swiss Federal Statistical Office in two periods: 2004/2005 and 2010/2011. Treatment options were compared between the two periods with adjustment for baseline characteristics of patients and treating institutions. RESULTS: A total of 24 497 patients (11 835 in 2004/2005; 12 662 in 2010/2011) were admitted to Swiss hospitals for uncomplicated diverticulitis. Between periods, the incidence increased from 81 to 85 admissions per 105 inhabitants per year. Elective admissions decreased from 46% (n = 5490) to 34% (n = 4294). The unadjusted resection rate decreased from 40% (n = 4730) to 34% (n = 4308). In the adjusted analysis, inpatients were more likely to have a resection in 2010/2011 than in 2004/2005 [odds ratio of 1.38 (95% confidence interval 1.25-1.54)]. In addition, private insurance, elective mode of admission and younger age increased the odds for resection while there was no evidence of an association between resection and either gender or comorbidities. CONCLUSION: The probability of colon resection for patients hospitalized with acute uncomplicated diverticulitis increased between periods while the overall number of colon resections declined. A change of practice expected given the paradigm shift towards conservative treatment could not be confirmed in this analysis.

Effect of n-3 fatty acids on markers of brain injury and incidence of sepsis-associated delirium in septic patients.

BACKGROUND: Data regarding immunomodulatory effects of parenteral n-3 fatty acids in sepsis are conflicting. In this study, the effect of administration of parenteral n-3 fatty acids on markers of brain injury, incidence of sepsis-associated delirium, and inflammatory mediators in septic patients was investigated. METHODS: Fifty patients with sepsis were randomized to receive either 2 ml/kg/day of a lipid emulsion containing highly refined fish oil (equivalent to n-3 fatty acids 0.12 mg/kg/day) during 7 days after admission to the intensive care unit or standard treatment. Markers of brain injury and inflammatory mediators were measured on days 1, 2, 3 and 7. Assessment for sepsis-associated delirium was performed daily. The primary outcome was the difference in S-100ß from baseline to peak level between both the intervention and the control group, compared by t-test. Changes of all markers over time were explored in both groups, fitting a generalized estimating equations model. RESULTS: Mean difference in change of S-100ß from baseline to peak level was 0.34 (95% CI: -0.18-0.85) between the intervention and control group, respectively (P = 0.19). We found no difference in plasma levels of S-100ß, neuron-specific enolase, interleukin (IL)-6, IL-8, IL-10, and C-reactive protein between groups over time. Incidence of sepsis-associated delirium was 75% in the intervention and 71% in the control groups (risk difference 4%, 95% CI -24-31%, P = 0.796). CONCLUSION: Administration of n-3 fatty acids did not affect markers of brain injury, incidence of sepsis-associated delirium, and inflammatory mediators in septic patients.

The cost of surgical training: analysis of operative time for laparoscopic cholecystectomy.

BACKGROUND: Duration of surgery is a main cost factor of surgical training. The purpose of this analysis of operative times for laparoscopic cholecystectomies (LC) was to quantify the extra time and related costs in regards to the surgeons' experience in the operating room (OR). METHODS: All LC performed between January 01, 2005 and December 31, 2008 in 46 hospitals reporting to the database of the Swiss Association for Quality Management in Surgery (AQC) were analyzed (n = 10,010). Four levels of seniority were specified: resident (R), junior consultant (JC), senior consultant (SC), and attending surgeon (AS). The differences in operative time according to seniority were investigated in a multivariable log-linear and median regression analysis controlling for possible confounders. The OR costs were calculated by using a full cost rate in a teaching hospital. RESULTS: A total of 9,208 LC were available for analysis; 802 had to be excluded due to missing data (n = 212) or secondary major operations (n = 590). Twenty-eight percent of the LC were performed by R as teaching operations (n = 2,591). Compared with R, the multivariable analysis of operative time showed a median difference of -2.5 min (-9.0; 4.8) for JC and -18 min (-25; -11) for SC and -28 min (-35; -10) for AS, respectively. The OR minute costs were 17.57, resulting in incremental costs of 492 (159; 615) per operation in case of tutorial assistance. CONCLUSIONS: The proportion of LC performed as tutorial assistance for R remains low. Surgical training in the OR causes relevant case-related extra time and therefore costs.

Impact of loss of high-molecular-weight von Willebrand factor multimers on blood loss after aortic valve replacement.

BACKGROUND: Severe aortic stenosis is associated with loss of the largest von Willebrand factor (vWF) multimers, which could affect primary haemostasis. We hypothesized that the altered multimer structure with the loss of the largest multimers increases postoperative bleeding in patients undergoing aortic valve replacement. METHODS: We prospectively included 60 subjects with severe aortic stenosis. Before and after aortic valve replacement, vWF antigen, activity, and multimer structure were determined and platelet function was measured by impedance aggregometry. Blood loss from mediastinal drainage and the use of blood and haemostatic products were evaluated perioperatively. RESULTS: Before operation, the altered multimer structure was present in 48 subjects (80%). Baseline characteristics and laboratory data were similar in all subjects. The median blood loss after 6 h was 250 (105-400) and 145 (85-240) ml in the groups with the altered and normal multimer structures, respectively (P=0.182). After 24 h, the cumulative loss was 495 (270-650) and 375 (310-600) ml in the groups with the altered and normal multimer structures, respectively (P=0.713). Multivariable analysis revealed no significant influence of multimer structure and platelet function on bleeding volumes after 6 and 24 h. After 24 h, there was no obvious difference in vWF antigen, activity, and multimer structure in subjects with and without the altered multimer structure before operation or in subjects with and without perioperative plasma transfusion. CONCLUSIONS: The altered vWF multimer structure before operation was not associated with increased bleeding after aortic valve replacement. Our findings might be explained by perioperative release of vWF and rapid recovery of the largest vWF multimers.

Microbial ureteral stent colonization in renal transplant recipients: frequency and influence on the short-time functional outcome.

Ureteral stent insertion at the time of renal transplantation significantly decreases complications of urine leakage and obstruction, but bears an intrinsic risk of microbial colonization. Associated urinary tract infection (UTI) may pose a significant risk for graft infection and subsequent graft failure, in particular, during high-level immunosuppression in the early phase after transplantation. The aims of this prospective study were (i) to assess the frequency of microbial ureteral stent colonization (MUSC) in renal transplant recipients by sonication, (ii) to compare the diagnostic value of sonication with that of conventional urine culture (CUC), (iii) to determine biofilm forming organisms, and (iv) to investigate the influence of MUSC on the short-time functional outcome. A total of 80 ureteral stents from 78 renal transplant recipients (deceased donors n = 50, living donors n = 28) were prospectively included in the study. CUC was obtained prior to renal transplantation and at ureteral stent removal. In addition, a new stent sonication technique was performed to dislodge adherent microorganisms. CUCs were positive in 4% of patients. Sonicate-fluid culture significantly increased the yield of microbial growth to 27% (P < 0.001). Most commonly isolated microorganisms by sonication were Enterococcus species (31%), coagulase-negative staphylococci (19%), and Lactobacillus species (19%), microorganisms not commonly observed in UTIs after renal transplantation. The median glomerular filtraton rate (GFR) of the study population increases from 39 mL/min immediately after transplantation (time point A) to 50 mL/min 6 month post transplantation (time point B). In patients without MUSC, the GFR improves from 39 mL/min (A) to 48 mL/min (B) and in patients with MUSC from 39 mL/min (A) to 50 mL/min (B), respectively. In summary, MUSC in renal transplant recipients is common and remains frequently undetected by routine CUC, but colonization had no measurable effect on renal function.

Effect of age on intraoperative cerebrovascular autoregulation and near-infrared spectroscopy-derived cerebral oxygenation.

BACKGROUND: Age is an important risk factor for perioperative cerebral complications such as stroke, postoperative cognitive dysfunction, and delirium. We explored the hypothesis that intraoperative cerebrovascular autoregulation is less efficient and brain tissue oxygenation lower in elderly patients, thus, increasing the vulnerability of elderly brains to systemic insults such as hypotension. METHODS: We monitored intraoperative cerebral perfusion in 50 patients aged 18-40 and 77 patients >65 yr at two Swiss university hospitals. Mean arterial pressure (MAP) was measured continuously using a plethysmographic method. An index of cerebrovascular autoregulation (Mx) was calculated based on changes in transcranial Doppler flow velocity due to changes in MAP. Cerebral oxygenation was assessed by the tissue oxygenation index (TOI) using near-infrared spectroscopy. End-tidal CO2, O2, and sevoflurane concentrations and peripheral oxygen saturation were recorded continuously. Standardized anaesthesia was administered in all patients (thiopental, sevoflurane, fentanyl, atracurium). RESULTS: Autoregulation was less efficient in patients aged >65 yr [by 0.10 (se 0.04; P=0.020)] in a multivariable linear regression analysis. This difference was not attributable to differences in MAP, end-tidal CO2, or higher doses of sevoflurane. TOI was not significantly associated with age, sevoflurane dose, or Mx but increased with increasing flow velocity [by 0.09 (se 0.04; P=0.028)] and increasing MAP [by 0.11 (se 0.05; P=0.043)]. CONCLUSIONS: Our results do not support the hypothesis that older patients' brains are more vulnerable to systemic insults. The difference of autoregulation between the two groups was small and most likely clinically insignificant.

Factors associated with positive blood cultures in outpatients with suspected bacteremia.

Blood cultures are routinely taken in outpatients with fever and suspected bacterial infections. However, in the majority of cases, they are not informative and of limited value for clinical decision making. The aim of this study was therefore to investigate factors associated with positive blood cultures in outpatients presenting to an outpatient clinic and emergency room. This was a case-control study of all outpatients with positive blood cultures from January 1, 2006 to October 31, 2007 and matched control patients with negative blood cultures in the same time period. Microbiology results and medical charts were reviewed to determine factors associated with positive blood cultures. The presence of a systemic inflammation response syndrome (SIRS) (OR 2.7, 95% Cl 1.0-7.2) and increased C-reactive protein (CRP) (OR 1.1 per 10 mg/l, 95% Cl 1.0-1.2) were the most powerful predictive values for the development of positive blood cultures. In positive cases serum albumin was lower (35 mg/l versus 39 mg/l) than in controls. SIRS, increasing CRP and low albumin were associated with positive blood cultures in outpatients. With simple clinical assessment and few laboratory tests indicative of infection, it is possible to define a group at higher risk for bacteremia in outpatients.

Lipid and lipoprotein profile in HIV-infected patients treated with lopinavir/ritonavir as a component of the first combination antiretroviral therapy.

We characterized lipid and lipoprotein changes associated with a lopinavir/ritonavir-containing regimen. We enrolled previously antiretroviral-naive patients participating in the Swiss HIV Cohort Study. Fasting blood samples (baseline) were retrieved retrospectively from stored frozen plasma and posttreatment (follow-up) samples were collected prospectively at two separate visits. Lipids and lipoproteins were analyzed at a single reference laboratory. Sixty-five patients had two posttreatment lipid profile measurements and nine had only one. Most of the measured lipids and lipoprotein plasma concentrations increased on lopinavir/ritonavir-based treatment. The percentage of patients with hypertriglyceridemia (TG >150 mg/dl) increased from 28/74 (38%) at baseline to 37/65 (57%) at the second follow-up. We did not find any correlation between lopinavir plasma levels and the concentration of triglycerides. There was weak evidence of an increase in small dense LDL-apoB during the first year of treatment but not beyond 1 year (odds ratio 4.5, 90% CI 0.7 to 29 and 0.9, 90% CI 0.5 to 1.5, respectively). However, 69% of our patients still had undetectable small dense LDL-apoB levels while on treatment. LDL-cholesterol increased by a mean of 17 mg/dl (90% CI -3 to 37) during the first year of treatment, but mean values remained below the cut-off for therapeutic intervention. Despite an increase in the majority of measured lipids and lipoproteins particularly in the first year after initiation, we could not detect an obvious increase of cardiovascular risk resulting from the observed lipid changes.