Evaluation of validity of the STOP-BANG questionnaire in major elective noncardiac surgery.

BACKGROUND: The STOP-BANG questionnaire screens for obstructive sleep apnoea (OSA) in surgical patients. In prior research, the association of STOP-BANG scores with comorbidities and outcomes was inconsistent. The objective of this study was to evaluate the validity of the STOP-BANG score. METHODS: We conducted a retrospective cohort study of patients undergoing major elective noncardiac surgery at the University Health Network (Toronto, ON, Canada) between 2011 and 2015. Cross-sectional construct validity was evaluated based on proportions with diagnosed OSA across STOP-BANG strata. Concurrent construct validity was assessed based on the correlation of STOP-BANG with ASA Physical Status (ASA-PS), the Revised Cardiac Risk Index, and the Charlson Comorbidity Index. Predictive validity was assessed based on the adjusted associations of STOP-BANG risk with 30-day mortality (logistic regression), cardiac complications (logistic regression), and length-of-stay (negative binomial regression). RESULTS: Of 26 068 patients in the cohort, 58% were in the low-risk STOP-BANG stratum, 23% in the intermediate-risk stratum, and 19% in the high-risk stratum. The proportion with previously diagnosed OSA was 4% (n=615) in the low-risk stratum, 12% (n=740) in the intermediate-risk stratum, and 44% (n=2142) in the high-risk stratum. The correlations of STOP-BANG with ASA-PS (Spearman ρ=0.28), Revised Cardiac Risk Index (ρ=0.24), and Charlson Comorbidity Index (ρ=0.10) were weak, albeit statistically significant (P<0.001). After risk-adjustment, STOP-BANG risk strata were not associated with 30-day mortality, cardiac complications, or length-of-stay. CONCLUSIONS: The STOP-BANG questionnaire has modest construct validity but did not predict postoperative mortality, hospital length-of-stay, or cardiac complications.

Association of preoperative anaemia with postoperative morbidity and mortality: an observational cohort study in low-, middle-, and high-income countries.

BACKGROUND: Anaemia is associated with poor postoperative outcomes, but few studies have described the impact of preoperative anaemia in low- and middle- (LMICs), and high-income countries (HICs). METHODS: This was a planned analysis of data collected during an international 7 day cohort study of adults undergoing elective inpatient surgery. The primary outcome was in-hospital death, and the secondary outcomes were in-hospital complications. Anaemia was defined as haemoglobin <12 g dl-1 for females and <13 g dl-1 for males. Hierarchical three-level mixed-effect logistic regression models were constructed to examine the associations between preoperative anaemia and outcomes. RESULTS: We included 38 770 patients from 474 hospitals in 27 countries of whom 11 675 (30.1%) were anaemic. Of these, 6886 (17.8%) patients suffered a complication and 198 (0.5%) died. Patients from LMICs were younger with lower ASA physical status scores, but a similar prevalence of anaemia [LMIC: 5072 (32.5%) of 15 585 vs HIC: 6603 (28.5%) of 23 185]. Patients with moderate [odds ratio (OR): 2.70; 95% confidence interval (CI): 1.88-3.87] and severe anaemia (OR: 4.09; 95% CI: 1.90-8.81) were at an increased risk of death in both HIC and LMICs. Complication rates increased with the severity of anaemia. Compared with patients in LMICs, those in HICs experienced fewer complications after an interaction term analysis [LMIC (OR: 0.92; 95% CI: 0.87-0.97) vs HIC (OR: 0.86; 95% CI: 0.84-0.87); P<0.01]. CONCLUSIONS: One-third of patients undergoing elective surgery are anaemic. These patients have an increased risk of complications and death. The prevalence of anaemia is similar amongst patients in LMICs despite their younger age and lower risk profile. CLINICAL TRIAL REGISTRATION: ISRCTN51817007.

Association between preoperative ambulatory heart rate and postoperative myocardial injury: a retrospective cohort study.

BACKGROUND: Resting heart rate is well established as a predictor of morbidity and mortality in the general population. However, the relationship between preoperative heart rate and perioperative outcomes, specifically myocardial injury, is unclear. METHODS: This retrospective cohort study included patients undergoing elective major non-cardiac surgery from 2008 to 2014 at a multisite healthcare system. The exposure was ambulatory heart rate measured during the outpatient preoperative clinic visit, whereas the outcome of interest was myocardial injury (peak postoperative troponin I concentration >30 ng L-1). Covariates included patient characteristics, comorbidities, and preoperative medications. We constructed several multivariable regression models that each modelled heart rate in a different manner, including as a simple continuous variable, categories, and fractional polynomials. RESULTS: The cohort included 41 140 patients, of whom 4857 (11.8%) experienced myocardial injury. Based on pre-specified heart categories thresholds, a heart rate ≥90 beats min-1 was associated with an elevated odds of myocardial injury compared with a heart rate <60 beats min-1 (adjusted odds ratio, 1.22; 95% confidence interval, 1.06-1.39; P=0.005). This result was consistent regardless of the method used for categorisation. When fractional polynomials were used to model heart rate, a 'J-shaped' relationship between heart rate and odds of myocardial injury was observed. CONCLUSIONS: This cohort study found that both very high preoperative heart rates, and possibly also very low heart rates, are associated with increased risk of myocardial injury. Whether heart rate is a modifiable risk factor, or rather simply a marker of underlying cardiac pathology, needs to be determined in further research.

Different methods of modelling intraoperative hypotension and their association with postoperative complications in patients undergoing non-cardiac surgery.

BACKGROUND: Associations between intraoperative hypotension (IOH) and postoperative complications have been reported. We examined whether using different methods to model IOH affected the association with postoperative myocardial injury (POMI) and acute kidney injury (AKI). METHODS: This two-centre cohort study included 10 432 patients aged ≥50 yr undergoing non-cardiac surgery. Twelve different methods to statistically model IOH [representing presence, depth, duration, and area under the threshold (AUT)] were applied to examine the association with POMI and AKI using logistic regression analysis. To define IOH, eight predefined thresholds were chosen. RESULTS: The incidences of POMI and AKI were 14.9% and 14.8%, respectively. Different methods to model IOH yielded effect estimates differing in size and statistical significance. Methods with the highest odds were absolute maximum decrease in blood pressure (BP) and mean episode AUT, odds ratio (OR) 1.43 [99% confidence interval (CI): 1.15-1.77] and OR 1.69 (99% CI: 0.99-2.88), respectively, for the absolute mean arterial pressure 50 mm Hg threshold. After standardisation, the highest standardised ORs were obtained for depth-related methods, OR 1.12 (99% CI: 1.05-1.20) for absolute and relative maximum decrease in BP. No single method always yielded the highest effect estimate in every setting. However, methods with the highest effect estimates remained consistent across different BP types, thresholds, outcomes, and centres. CONCLUSIONS: In studies on IOH, both the threshold to define hypotension and the method chosen to model IOH affects the association of IOH with outcome. This makes different studies on IOH less comparable and hampers clinical application of reported results.

Influence of anaemia and red blood cell transfusion on mortality in high cardiac risk patients undergoing major non-cardiac surgery: a retrospective cohort study.

BACKGROUND.: Perioperative anaemia is common. Physicians believe that patients at increased cardiac risk do not tolerate anaemia and, consequently, these patients receive transfusions earlier and more often. This practice runs counter to a growing body of evidence that perioperative red blood cell (RBC) transfusion is harmful The aims of this study were as follows: (i) to assess the effects of transfusion at moderate to severely low ranges of postoperative haemoglobin concentrations; and (ii) to assess whether transfusion was beneficial in patients at high cardiac risk within these haemoglobin ranges. METHODS.: A single-centre retrospective cohort study enrolled 75 719 consecutive major, non-cardiac surgery patients. Multivariable logistic regressions with 98.4% confidence intervals looking at specific nadir postoperative haemoglobin groups were compared to examine the effects of anaemia, RBC transfusion, and cardiac risk on postoperative 30 day in-hospital mortality. RESULTS.: Patients at moderate to high cardiac risk had a two-fold greater prevalence of preoperative anaemia. In unadjusted analysis, RBC transfusion was associated with increased mortality at all transfusion thresholds in all patients. After adjustment, RBC transfusion in patients with high cardiac risk was associated with decreased mortality when the postoperative haemoglobin concentration was <80 g litre -1 [odds ratio 0.37 (98.4% confidence interval 0.17-0.77)]. CONCLUSIONS.: High cardiac risk was associated with increased incidence of anaemia, transfusion, and mortality. Red blood cell transfusion is associated with reduced mortality only in high cardiac risk patients with nadir postoperative haemoglobin concentration <80 g litre -1 . Transfusion, the main treatment for postoperative anaemia, does not appear to be associated with reduced postoperative mortality at higher nadir haemoglobin ranges.

Chronic postsurgical pain in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia (ENIGMA)-II trial.

BACKGROUND: Previous animal and clinical studies showed that nitrous oxide may produce long-term analgesia. The aim of this study was to evaluate the effect of nitrous oxide in preventing chronic postsurgical pain. We also explored whether methylenetetrahydrofolate reductase gene polymorphisms (1298A>C, 667C>T) would enhance nitrous oxide analgesia. METHODS: We conducted a telephone interview at 12 months after surgery on 2924 (41.1%) patients enrolled in the Evaluation of Nitrous Oxide in the Gas Mixture for Anaesthesia-II trial. Pain at the wound site was recorded using the modified brief pain inventory and the neuropathic pain questionnaire. General health status was measured using the EQ-5D questionnaire. Genotyping was performed in a subset of 674 Asian patients in Hong Kong. RESULTS: At 12 months after surgery, 356 (12.2%) patients reported chronic postsurgical pain at the wound site and 112 (3.8%) patients had severe pain and required regular analgesic interventions. Nitrous oxide did not affect the rate of chronic postsurgical pain (11.8% nitrous oxide group; 12.5% no nitrous oxide group), relative risk (95% confidence intervals): 0.94 (0.75-1.17), P=0.57. However, in a planned subgroup analysis, nitrous oxide reduced the risk of chronic postsurgical pain in Asian patients, relative risk (95% confidence intervals): 0.70 (0.50-0.98), P=0.031. Patients who were homozygous for either gene polymorphism and who received nitrous oxide during surgery were less likely to report chronic postsurgical pain. CONCLUSIONS: Nitrous oxide administration had no impact on chronic postsurgical pain, but benefits may still be possible in Asian patients and patients with variants in methylenetetrahydrofolate reductase gene. CLINICAL TRIAL REGISTRATION: NCT00430989.

Effectiveness of platelet inhibition on major adverse cardiac events in non-cardiac surgery after percutaneous coronary intervention: a prospective cohort study.

BACKGROUND: Platelet inhibition is mandatory therapy after percutaneous coronary intervention (PCI). Withdrawal of oral antiplatelet agents has been linked to increased incidence of postoperative adverse cardiac events in post-PCI patients having non-cardiac surgery (NCS). There is limited knowledge of temporal changes in platelet inhibition in this high-risk surgical population. We therefore performed a multicentre prospective cohort study evaluating perioperative platelet function and its association with postoperative major adverse cardiac events (MACE). METHODS: In 201 post-PCI patients having NCS, we assessed the association between platelet function and postoperative MACE. We performed perioperative platelet function testing using a platelet mapping assay (PMA). Troponin-I was measured every 8 h for 2 days, then daily until day 5. Myocardial infarction was assessed using the third universal definition. We used multivariable logistic regression to assess the association between platelet inhibition and MACE. RESULTS: Major adverse cardiac events occurred in 40 patients within 30 days of surgery. Thirty-two of these events were non-ST-elevation myocardial infarction, four ST-elevation myocardial infarction, and four exacerbation of congestive heart failure. We were unable to show an association between platelet inhibition and MACE. The PMA showed declining levels of platelet inhibition the longer the antiplatelet therapy was withheld before surgery. Logistic regression did not show an association between preoperative platelet function or the type of stent and MACE. We found an increased cardiac risk of MACE after surgery within 6 weeks of PCI. CONCLUSIONS: The incidence of MACE in patients undergoing NCS after previous PCI is high in spite of adequate perioperative antiplatelet therapy. CLINICAL TRIAL REGISTRATION: NCT 01707459 (registered at http://www.clinicaltrials.gov).

Choice of fluid in acute illness: what should be given? An international consensus.

Fluid management during critical illness is a dynamic process that may be conceptualized as occurring in four phases: rescue, optimization, stabilization, and de-escalation (mobilization). The selection and administration of resuscitation fluids is one component of this complex physiological sequence directed at restoring depleted intravascular volume. Presently, the selection of i.v. fluid is usually dictated more by local practice patterns than by evidence. The debate on fluid choice has primarily focused on evaluating outcome differences between 'crystalloids vs colloids'. More recently, however, there is interest in examining outcome differences based on the chloride content of crystalloid solutions. New insights into the conventional Starling model of microvascular fluid exchange may explain that the efficacy of colloids in restoring and maintaining depleted intravascular volume is only moderately better than crystalloids. A number of investigator-initiated, high-quality, randomized controlled trials have demonstrated that modest improvements in short-term physiological endpoints with colloids have not translated into better patient-centred outcomes. In addition, there is substantial evidence that certain types of fluids may independently worsen patient-centred outcomes. These include hydroxyethyl starch and albumin solutions in selected patient populations. There is no evidence to support the use of other colloids. The use of balanced salt solutions in preference to 0.9% saline is supported by the absence of harm in large observational studies. However, there is no compelling randomized trial-based evidence demonstrating improved clinical outcomes with the use of balanced salt solutions compared with 0.9% saline at this time.

Reliability of the American Society of Anesthesiologists physical status scale in clinical practice.

BACKGROUND: Previous studies, which relied on hypothetical cases and chart reviews, have questioned the inter-rater reliability of the ASA physical status (ASA-PS) scale. We therefore conducted a retrospective cohort study to evaluate its inter-rater reliability and validity in clinical practice. METHODS: The cohort included all adult patients (≥18 yr) who underwent elective non-cardiac surgery at a quaternary-care teaching institution in Toronto, Ontario, Canada, from March 2010 to December 2011. We assessed inter-rater reliability by comparing ASA-PS scores assigned at the preoperative assessment clinic vs the operating theatre. We also assessed the validity of the ASA-PS scale by measuring its association with patients' preoperative characteristics and postoperative outcomes. RESULTS: The cohort included 10 864 patients, of whom 5.5% were classified as ASA I, 42.0% as ASA II, 46.7% as ASA III, and 5.8% as ASA IV. The ASA-PS score had moderate inter-rater reliability (κ 0.61), with 67.0% of patients (n=7279) being assigned to the same ASA-PS class in the clinic and operating theatre, and 98.6% (n=10 712) of paired assessments being within one class of each other. The ASA-PS scale was correlated with patients' age (Spearman's ρ, 0.23), Charlson comorbidity index (ρ=0.24), revised cardiac risk index (ρ=0.40), and hospital length of stay (ρ=0.16). It had moderate ability to predict in-hospital mortality (receiver-operating characteristic curve area 0.69) and cardiac complications (receiver-operating characteristic curve area 0.70). CONCLUSIONS: Consistent with its inherent subjectivity, the ASA-PS scale has moderate inter-rater reliability in clinical practice. It also demonstrates validity as a marker of patients' preoperative health status.

The effects of a treatment protocol for cardiac surgical patients with excessive blood loss on clinical outcomes.

BACKGROUND AND OBJECTIVES: Excessive blood loss (EBL) is a common complication of cardiac surgery that is associated with adverse events. The objective of this before/after study was to determine whether the implementation of a protocol for management of cardiac surgical patients with EBL was associated with improved clinical outcomes. MATERIALS AND METHODS: In November 2002, a protocol for prompt identification and aggressive management of cardiac surgical patients with EBL was implemented at our institution. The independent relationship between protocol implementation and adverse outcomes was measured by comparing the outcomes of patients who received > or = 4 RBC (red blood cell) units within 1 day of surgery and were operated on before protocol implementation (2000-02) with those operated on after protocol implementation (2003-05), using multivariable logistic regression analysis to control for the effects of confounders. The primary outcome was a composite of adverse events that included death, renal failure, stroke, and sepsis. Bootstrapping was used to confirm the validity of the results. RESULTS: Of the 11,314 patients who underwent surgery during the study period, 1875 (16.6%) received > or = 4 RBC units within 1 day of surgery, with 958 and 917 in the pre- and postprotocol periods, respectively. The composite adverse outcome occurred in 164 (17.1%) patients in the preprotocol period and 115 (12.5%) patients in the postprotocol period (P = 0.005). Protocol implementation was independently associated with reduced odds of the composite adverse outcome (odds ratio 0.67; 95% confidence interval 0.50, 0.91; P = 0.01). This estimate was stable in bootstrap sampling. CONCLUSION: Implementation of a protocol to manage EBL in cardiac surgery was independently associated with improved outcomes.

Hemodilution during cardiopulmonary bypass is an independent risk factor for acute renal failure in adult cardiac surgery.

BACKGROUND: This observational study sought to determine whether the degree of hemodilution during cardiopulmonary bypass is independently related to perioperative acute renal failure necessitating dialysis support. METHODS: Data were prospectively collected on consecutive patients undergoing cardiac operations with cardiopulmonary bypass from 1999 to 2003 at a tertiary care hospital. The independent relationship was assessed between the degree of hemodilution during cardiopulmonary bypass, as measured by nadir hematocrit concentration, and acute renal failure necessitating dialysis support. Multivariate logistic regression was used to control for variables known to be associated with perioperative renal failure and anemia. RESULTS: Of the 9080 patients included in the analysis, 1.5% (n = 134) had acute renal failure necessitating dialysis support. There was an independent, nonlinear relationship between nadir hematocrit concentration during cardiopulmonary bypass and acute renal failure necessitating dialysis support. Moderate hemodilution (nadir hematocrit concentration, 21%-25%) was associated with the lowest risk of acute renal failure necessitating dialysis support; the risk increased as nadir hematocrit concentration deviated from this range in either direction (P = .005). Compared with moderate hemodilution, the adjusted odds ratio for acute renal failure necessitating dialysis support with severe hemodilution (nadir hematocrit concentration <21%) was 2.34 (95% confidence interval, 1.47-3.71), and for mild hemodilution (nadir hematocrit concentration >25%) it was 1.88 (95% confidence interval, 1.02-3.46). CONCLUSIONS: Given that there is an independent association between the degree of hemodilution during cardiopulmonary bypass and perioperative acute renal failure necessitating dialysis support, patient outcomes may be improved if the nadir hematocrit concentration during cardiopulmonary bypass is kept within the identified optimal range. Randomized clinical trials, however, are needed to determine whether this is a cause-effect relationship or simply an association.

Epidural analgesia reduces postoperative myocardial infarction: a meta-analysis.

UNLABELLED: Postoperative cardiac morbidity and mortality continue to pose considerable risks to surgical patients. Postoperative epidural analgesia is considered to have beneficial effects on cardiac outcomes. The use in high-risk cardiac patients remains controversial. No study has shown that postoperative epidural analgesia decreases postoperative myocardial infarction (PMI) or death. All studies are underpowered to show such a result, and the cost of conducting a large trial is prohibitive. We performed a metaanalysis to determine whether postoperative epidural analgesia continued for more than 24 h after surgery reduces PMI or in-hospital death. The available databases were searched for randomized controlled trials of epidural analgesia that was extended at least 24 h into the postoperative period. The search yielded 17 studies, of which 11 were randomized controlled trials comprising 1173 patients. Metaanalysis was conducted by using the fixed-effects model, calculating both an odds ratio and a rate difference. Postoperative epidural analgesia resulted in better analgesia for the first 24 h after surgery. The rate of PMI was 6.3%, with lower rates in the Epidural group (rate difference, -3.8%; 95% confidence interval [CI] -7.4%, -0.2%; P = 0.049). The frequency of in-hospital death was 3.3%, with no significant difference between Epidural and Nonepidural groups (rate difference, -1.3%; 95% CI, -3.8%, 1.2%, P = 0.091). Subgroup analysis of postoperative thoracic epidural analgesia showed a significant reduction in PMI in the Epidural group (rate difference, -5.3%; 95% CI, -9.9%, -0.7%; P = 0.04). IMPLICATIONS: Postoperative epidural analgesia, especially thoracic epidural analgesia, continued for more than 24 h reduces postoperative myocardial infarctions.

Nitrous oxide-induced increased homocysteine concentrations are associated with increased postoperative myocardial ischemia in patients undergoing carotid endarterectomy.

UNLABELLED: Nitrous oxide anesthesia causes increased postoperative plasma homocysteine levels. Acute increases in plasma homocysteine are associated with impaired endothelial function and procoagulant effects. This nitrous oxide-induced plasma homocysteine increase may therefore affect the risk of perioperative cardiovascular events. This prospective, randomized study was therefore designed to evaluate the effect of nitrous oxide anesthesia and postoperative plasma homocysteine levels on myocardial ischemia in patients undergoing carotid endarterectomy. After institutional review board approval and written informed consent, 90 ASA Class I-III patients presenting for elective carotid endarterectomy were randomized to receive general anesthesia with or without nitrous oxide. Prior to induction, on arrival in the postanesthesia care unit, and after 48 h, blood samples were obtained for homocysteine analysis. Three hours prior to induction and for 48 h postoperatively patients were monitored by a three-channel, seven-lead Holter monitor. Postoperatively in the postanesthesia care unit and at 48 h the nitrous oxide group had increased mean plasma homocysteine concentrations of 15.5 +/- 5.9 and 18.8 +/- 14.7 when compared with the nonnitrous group of 11.4 +/- 5.2 and 11.3 +/- 4.0 micromol/L, P: < 0.001. The nitrous oxide group had an increased incidence of ischemia (46% vs. 25%, P: < 0.05), significantly more ischemia (63 +/- 71 vs. 40 +/- 68 min, P: < 0.05), had more ischemic events (82 vs. 53, P: < 0.02), and had more ischemic events lasting 30 min (23 vs. 14, P: < 0.05) than the nonnitrous group. This study reconfirmed that intraoperative nitrous oxide is associated with postoperative increases in plasma homocysteine concentration. This was associated with an increase in postoperative myocardial ischemia. IMPLICATIONS: Use of nitrous oxide during carotid artery surgery induces increases in postoperative plasma homocysteine concentration and is associated with increases in postoperative myocardial ischemia.

The addition of continuous intravenous infusion of ketorolac to a patient-controlled analgetic morphine regime reduced postoperative myocardial ischemia in patients undergoing elective total hip or knee arthroplasty.

This double-blind randomized trial assessed the effect of adding an intravenous continuous infusion of ketorolac to a patient-controlled analgesia (PCA) morphine regimen on analgesia, heart rate, arterial blood pressure, and postoperative myocardial ischemia. Patients having elective total hip or knee replacement were randomized to receive ketorolac 30 mg bolus, followed by an infusion of 5 mg/h for 24 h or placebo. All patients had access to PCA morphine (20 microg/kg bolus, with a lockout of 6 min). Patients were monitored for pain visual analog scale, blood pressure, heart rate, and ST segment depression via a continuous Holter monitor. ST depression of 1 mm 60 ms after the J point was considered significant if it lasted more than 1 min. There was no difference in demographics, risk factors, or cardiac medications between the groups. Ketorolac-treated patients had significantly better pain control at 2, 6, and 24 h. There was significant morphine sparing at all times after 3 h. There was no difference in the number of ischemic events between the groups. The ischemic episodes of the patients who received ketorolac occurred at slower heart rates (97 +/- 15 vs 114 +/- 16 bpm, P = 0.001) than those of patients in the placebo group. The duration of ST depression was shorter in ketorolac-treated patients (24 +/- 35 vs 76 +/- 95 min, P < 0.05). All ST depressions were clinically silent. Logistic regression of factors predicting ischemia included the use of calcium channel blockers and low pain score. These results suggest that analgesia with ketorolac reduces the duration of ischemic episodes in the first 24 h postoperatively.

Continuous epidural ropivacaine 0.2% for analgesia after lower abdominal surgery.

The purpose of this study was to determine whether a lumbar epidural infusion of ropivacaine 0.2% would provide effective analgesia with an acceptably low incidence of motor blockade and side effects after lower abdominal surgery. After combined general and epidural anesthesia and surgery, 125 patients were randomly assigned to receive either saline or ropivacaine 0.2% at a rate of 6, 8, 10, 12, or 14 mL/h (Groups R6, R8, R10, R12, and R14, respectively) for 21 h. Supplemental analgesia, if required, was provided with intravenous patient-controlled analgesia with morphine. Data were collected at 4, 8, and 21 h, and included morphine consumption, pain scores at rest and with coughing, motor and sensory block, and adverse events. Cumulative morphine consumption was less in Groups R10, R12, and R14 compared with the saline group. At 4 h analgesia was better among patients receiving ropivacaine, but at 21 h pain scores were identical. Sensory blockade at 8 and 21 h was greater in the ropivacaine groups compared with the saline group. Approximately 30% of R8, R10, and R12 patients, and 63% of R14 patients had demonstrable motor block of the lower limbs at 21 hours. We conclude that lumbar epidural ropivacaine 0.2% reduces parenteral morphine requirements but has little effect on pain scores and may be associated with motor blockade.

Continuous intravenous administration of ketorolac reduces pain and morphine consumption after total hip or knee arthroplasty.

The purpose of this study was to determine the analgesic efficacy, opioid-sparing effect, and tolerability of ketorolac administered as an intravenous (i.v.) bolus followed by a continuous infusion after total hip or knee arthroplasty. After general anesthesia, patients received either placebo or ketorolac 30 mg i.v. as a bolus over 15-30 s followed by a continuous i.v. infusion of ketorolac 5 mg/h for 24 h. All patients received patient-controlled i.v. morphine with no background infusion. Patients were assessed at 2, 4, 6, and 24 postoperatively with respect to analgesia, morphine consumption, side effects, and blood loss. Patients receiving ketorolac reported were less sedated and required fewer antiemetics. There was no difference in blood loss. Patients receiving ketorolac reported better analgesia and used less morphine (35% for hips and 44% for knees) than those receiving placebo.

Epidural morphine reduces the risk of postoperative myocardial ischaemia in patients with cardiac risk factors.

Perioperative myocardial ischaemia is a predictor of postoperative cardiac morbidity (PCM). Epidural anaesthesia and adequate perioperative analgesia have been shown to improve myocardial oxygen dynamics due to interruption of pain and sympathetic pathways. The aim of the present study was to compare the incidence of ischaemia after either general anaesthesia followed by parenteral analgesia with morphine or combined epidural/general anaesthesia followed by analgesia with epidural morphine. In a prospective observer-blinded analysis of the occurrence of ischaemia, 55 patients (epidural = 29/parenteral = 26) scheduled for elective surgery with defined risks for ischaemic cardiac disease were entered and followed for 24 hr after surgery with two-lead continuous Holter monitoring. Groups were similar with respect to age, weight, modified Goldman (Detsky) risk classification and the use of cardiac medications. Fewer patients receiving the epidural anaesthesia/analgesia had ischaemic episodes (17.2 vs 50.0%, P = 0.01), and tachyarrhythmias (20.7 vs 50.0%, P < 0.05). Epidural patients had a four-fold reduction of the relative risk for either event (P < 0.001). All ischaemic events were asymptomatic and unrecognized (silent). All major morbid events (n = 5) (MI, congestive heart failure and death) occurred in patients who had perioperative episodes of ischaemia. There were three distinct peaks in onset of ischaemia, at 1-4 hr, 9-12 hr and 22-24 hr postoperatively. One third of postoperative ischaemic events occurred within the first four hours after operation and lasted from 1 to 31 min. Forty-two percent of ischaemic episodes were associated with a heart rate > 100 bpm, or an increase of 20% over the baseline heart rate. We conclude that epidural anaesthesia/analgesia reduces but does not eliminate the risk of myocardial ischaemia and tachyarrhythmia. We were unable to determine any associated reduction in the risk of PCM.