 |
|
Protective Effects of Epidural Analgesia on Pulmonary Complications After Abdominal and Thoracic SurgeryA Meta-Analysis
Daniel M. Pöpping, MD;
Nadia Elia, MD;
Emmanuel Marret, MD;
Camille Remy, MD;
Martin R. Tramèr, MD, DPhil
Arch Surg. 2008;143(10):990-999.
ABSTRACT
| |
Objective To review the impact of epidural vs systemic analgesia on postoperative pulmonary complications.
Data Sources Search of databases (1966 to March 2006) and bibliographies.
Study Selection Inclusion criteria were randomized comparison of epidural vs systemic analgesia lasting 24 hours or longer postoperatively and reporting of pulmonary complications, lung function, or gas exchange. Fifty-eight trials (5904 patients) were included.
Data Extraction Articles were reviewed and data extracted. Data were combined using fixed-effect and random-effects models.
Data Synthesis The odds of pneumonia were decreased with epidural analgesia (odds ratio [OR], 0.54; 95% confidence interval [CI], 0.43-0.68), independent of site of surgery or catheter insertion, duration of analgesia, or regimen. The effect was weaker in trials that used patient-controlled analgesia in controls (OR, 0.64; 95% CI, 0.49-0.83) compared with trials that did not (OR, 0.30; 95% CI, 0.18-0.49) and in larger studies (OR, 0.62; 95% CI, 0.47-0.81) compared with smaller studies (OR, 0.37; 95% CI, 0.23-0.58). From 1971-2006, the incidence of pneumonia with epidural analgesia remained about 8% but decreased from 34% to 12% with systemic analgesia (P < .001); consequently, the relative benefit of epidural analgesia decreased also. Epidural analgesia reduced the need for prolonged ventilation or reintubation, improved lung function and blood oxygenation, and increased the risk of hypotension, urinary retention, and pruritus. Technical failures occurred in 7%.
Conclusion Epidural analgesia protects against pneumonia following abdominal or thoracic surgery, although this beneficial effect has lessened over the last 35 years because of a decrease in the baseline risk.
INTRODUCTION
Epidural local anesthetics, with or without opioids, provide better postoperative pain relief than systemic opioids.1-2 Epidural local anesthetics reduce central sympathetic stimulation, with subsequent favorable effects on coagulation and homeostasis and on gastrointestinal, metabolic, and immune function.3-4 In patients undergoing surgery for hip replacement, epidural local anesthetics were shown to reduce the incidence of venous thrombosis.5 It was also suggested that in patients undergoing vascular surgery, epidural analgesia may reduce the risk of cardiac events.6
The impact of epidural analgesia on the risk of pneumonia in a high-risk population has never been adequately investigated in a meta-analysis. Previously published meta-analyses either did not report on the risk of pneumonia1, 6; reported on composite "pulmonary complications" outcomes, lumping very different end points, such as pulmonary infection, atelectasis, respiratory failure, or reintubation7-8; included populations at low risk of postoperative pneumonia (for instance, patients undergoing surgery for hip fracture)5; or included data from only a very limited number of small trials that tested epidural analgesia.9 The largest meta-analysis so far included data on any neuraxial blockade (intrathecal and/or epidural analgesia with or without general anesthesia) and it remained unclear what the impact of epidural analgesia in patients at high risk of postoperative pneumonia was.10 Moreover, none of these meta-analyses addressed the potential of harm related to the use of epidurals. This uncertainty may be one reason why a recently published report on the behalf of the American College of Physicians concluded that the evidence for epidural analgesia to reduce pulmonary complications after noncardiothoracic surgery was conflicting or insufficient.11
The benefit of epidural analgesia to reduce the risk of postoperative pulmonary complications, specifically pneumonia, remains ambiguous. Our meta-analysis was designed to address this issue.
METHODS
LITERATURE REVIEW
A wide search strategy was used to retrieve all trials that randomized surgical patients to either epidural or systemic analgesia and that reported on pulmonary complications, lung function test results, or gas exchange parameters. Since there was an intention to include only data from patients at high risk of pulmonary complications, we concentrated on abdominal or thoracic surgery.12 The MEDLINE, Cochrane, BIOSIS, and CINAHL databases were searched from 1966 to March 2006 for reports related to epidural analgesia (epidural, peridural, extradural) and abdominal or thoracic surgery using the Boolean meanings of "or" and "and." Bibliographies of selected articles were checked for additional references. There was no language restriction.
Trials in adults (aged  18 years) in which epidural analgesia was started preoperatively, intraoperatively, or immediately postoperatively and lasted at least 24 hours were included. Systemic analgesia was defined as opioids given alone or in combination with nonopioid analgesics. When controls received locoregional analgesia (for instance, intercostal nerve blocks), the trial was not considered. Trials with fewer than 10 patients per group or trials on trauma patients were excluded. Each of the retrieved articles was reviewed by one of us (D.M.P.) for inclusion. Queries were resolved by discussion with 2 coauthors (E.M. and C.R.). The primary investigators of 31 reports were contacted to obtain additional information since data reporting was inadequate; 6 answered and of 3 of those,13-15 additional data were included in our analyses.
DATA EXTRACTION AND ANALYSIS
One of us (D.M.P.) extracted information on type of epidural analgesia (level of insertion, duration, regimen), systemic analgesia (regimen, route of administration), number of patients, length of observation period, and surgery. Data on pulmonary complications, lung function, gas exchange, and adverse events were extracted from tables or text; definitions were taken as reported in the original articles. For each included trial, the method of randomization, concealment of treatment allocation, degree of blinding, and reporting of dropouts was assessed. Two of us (C.R. and E.M.) checked all extracted information. Discrepancies were resolved by discussion with a coauthor (M.R.T.).
For continuous data, weighted mean differences with 95% confidence intervals (CIs) were calculated. For dichotomous data, Peto odds ratios (ORs) with 95% CIs were computed since there were many zero cells. Trials that had 2 zero cells for an end point (ie, no event occurred in either group) were excluded from the summary OR. An OR less than 1 indicated a beneficial effect with epidural. When the 95% CI around the OR did not include 1, the result was considered statistically significant.
We performed formal heterogeneity testing (P < .10 was considered heterogeneous). When the data were homogenous, we used a fixed-effect model to combine data. When the data were heterogeneous, there was an intention to use a random-effects model. However, sensitivity analyses were performed to identify sources of heterogeneity.
Since ORs cannot be easily extrapolated into daily clinical practice, we computed the number needed to treat (NNT) for beneficial effects and the number needed to harm (NNH) for harmful effects using the control event rate and the OR. We calculated 95% CIs around the NNT/NNH only when the 95% CI around the OR indicated that the result was statistically significant.16
Statistical analyses were performed using STATA (version 9; StataCorp, College Station, Texas) and ReviewManager software (version 4.2; Cochrane Collaboration, Oxfordshire, England).
RESULTS
RETRIEVED AND INCLUDED STUDIES
We retrieved 789 reports but rejected 731 for a variety of reasons, including 3 duplicate publications17-22 (Figure 1). A total of 58 studies met all inclusion criteria.13-15,23-77 They were published between 1971 and 2006 and reported on data from 5904 patients. Of the 41 epidural studies that were included in a previous similar meta-analysis,9 we excluded 21 because the surgery was not abdominal or thoracic, data on postoperative pulmonary complications or lung function could not be extracted, they were not randomized, or controls did not receive systemic opioids.
The included trials tested thoracic, lumbar, or both thoracic and lumbar epidurals. Epidural analgesia was commenced before or at the end of surgery; median duration was 3 days (range, 2 to 5 days). Epidural regimens were with local anesthetics, opioids, or both. Controls received subcutaneous, intravenous, or intramuscular opioids with or without nonopioid analgesics. Opioids were given on demand, regularly, or via patient-controlled analgesia (PCA).
PNEUMONIA
Nineteen trials (3504 patients) reported the number of patients who had pneumonia. With epidural analgesia, the odds of pneumonia were significantly decreased (OR, 0.54; 95% CI, 0.43-0.68; NNT, 18 [range, 14-27]) (Table 1). The symmetrical funnel suggested that publication bias was unlikely (Figure 2); however, the data were heterogeneous (Table 1).
|
|
|
|
Table 1. Pneumonia, Prolonged Ventilation, and Reintubation
|
|
|
|
|
|
|
Figure 2. Funnel plot of natural logarithm of odds ratio vs sample size among all studies reporting on pneumonia. Data are odds ratios plotted against weight (sample size) for each trial included in the meta-analysis on pneumonia. An odds ratio of less than 1 signifies less pneumonia with epidural analgesia. The sizes of the bubbles correspond to the sizes of the trials. The dotted vertical line represents the combined odds ratio (0.54).
|
|
|
Sensitivity analyses were performed to identify potential sources of heterogeneity (Table 1). We looked at the impact of type of analgesia in controls (PCA vs none), site of surgery (thoracic vs abdominal), insertion site of epidurals (thoracic vs lumbar), duration of analgesia (2-5 days), epidural drug regimens (local anesthetics vs opioids vs both), and trial size (<100 vs >100 patients per group). Epidural analgesia was significantly more efficacious compared with systemic analgesia in preventing pneumonia in trials where controls did not receive PCA (OR, 0.30) compared with trials where controls did receive such a device (OR, 0.64) (P < .01). Similarly, epidural analgesia was more efficacious in preventing pneumonia in trials with fewer than 100 patients per group (OR, 0.37) compared with larger trials (OR, 0.62) (P = .08). Site of surgery, insertion site of epidurals, and duration of postoperative analgesia had no significant impact on the efficacy of epidurals. Epidural local anesthetics were as efficacious as combinations of local anesthetics and opioids. The efficacy of epidural opioids alone was tested in one small trial only.
Since the trials were published over a period of 35 years, we tested whether older trials reported on different estimates of efficacy compared with younger trials. First, cumulative meta-analysis was performed using pneumonia as the end point (Figure 3). Over the years, the cumulative OR moved toward unity, suggesting that the efficacy of epidurals, compared with systemic analgesia, had decreased between 1971 and 2006. Second, trials were divided into subgroups representing 4 decades since publication of the first trial in 1971; meta-analyses were performed within each stratum (Figure 4A). In the 1970s, 2 trials were published; the OR for the prevention of pneumonia with epidural compared with systemic analgesia was 0.17 (NNT, 4). In the 1980s, the OR was 0.36 (NNT, 9); in the 1990s, it was 0.46 (NNT, 23); and between 2000 and 2006, it was 0.62 (NNT, 25). Although the OR moved toward unity, the evidence that the effect of epidurals on pneumonia was modified by periods was weak ( 23 = 5.04; P = .17).
|
|
|
Figure 3. Postoperative pneumonia with epidural analgesia compared with systemic analgesia: individual trials and cumulative meta-analysis. *Odds ratio (OR) and 95% confidence interval (CI) in individual trials.  Cumulative OR and 95% CIs. Trials are arranged according to date of publication. Trials with zero events are not shown.
|
|
|
|
|
|
|
Figure 4. Relationship between the year of publication, the incidence of pneumonia with epidural and systemic analgesia, and the efficacy of epidural analgesia in preventing pneumonia compared with systemic analgesia. Gray symbols indicate trials that used patient-controlled analgesia in controls; white symbols, trials that did not use patient-controlled analgesia in controls. Periods for subgroup analyses were chosen by convenience. Score test for linear trend of odds with year: the odds ratio (OR) estimate is an approximation to the OR for a 1-unit increase per year. Hetero indicates heterogeneity; CI, confidence interval. Trials with zero events are not shown.
|
|
|
To better understand the change in efficacy of epidural analgesia over time, we analyzed the incidences of pneumonia with epidural and systemic analgesia separately (Figure 4B and C). In patients receiving epidural analgesia, the average incidences of pneumonia during the 4 decades were between 3.9% and 8.6%; the score test for linear trend of odds with year was not significant (21 = 0.00; P = .99) (Figure 4B). In controls receiving systemic analgesia, the average incidence of pneumonia during the 4 decades decreased from 34.3% to 8.3% and then increased to 12%; the score test for linear trend of odds with year was highly significant (21 = 21.02; P < .001) (Figure 4C). The definition of pneumonia, the use of concomitant physiotherapy, and the technique of epidural analgesia have not changed over time. However, there was a change in systemic analgesia techniques toward PCA and multimodal analgesia methods (Table 2).
|
|
|
|
Table 2. Randomized Trials Reporting on Postoperative Pneumonia
|
|
|
Since the method of analgesia in controls (PCA) and trial size had an impact on the incidence of pneumonia in controls and the efficacy of epidurals, 2 further sensitivity analyses were performed. In control groups, the score test for linear trend of odds with year remained statistically significant when only trials that did not use PCA in controls were considered (21 = 19.58; P < .001) or when only trials with fewer than 100 patients per group were considered (21 = 33.83; P < .001).
FURTHER OUTCOMES
Epidural analgesia significantly decreased the odds of prolonged (>24 hours) ventilation and reintubation (Table 1). Definitions and diagnosis of atelectasis and respiratory depression varied considerably between trials; meta-analysis was deemed inappropriate. Epidural analgesia significantly increased forced vital capacity at 24 hours, forced expiratory volume in 1 second at 24 hours, and peak expiratory flow rate at 24 hours (Table 3). Epidural analgesia significantly increased arterial oxygen pressure at 24 and 72 hours (Table 3).
|
|
|
|
Table 3. Pulmonary Function and Gas Exchange
|
|
|
Fourteen trials reported on the incidence of postoperative myocardial infarction. Definitions of infarction included an increase in serum concentration of myocardial-specific isoenzyme fractions of creatine kinase or lactic dehydrogenase and typical electrocardiogram changes (elevation/depression of the ST segment and/or new Q waves). The odds of myocardial infarction were significantly decreased with epidural analgesia (OR, 0.55; NNT, 48) (Table 4).
|
|
|
|
Table 4. Further Beneficial and Harmful Effects of Epidural Analgesia
|
|
|
Epidural analgesia significantly increased the odds of intraoperative arterial hypotension (OR, 2.03; NNH, 41) and of postoperative urinary retention (OR, 2.15; NNH, 16) (Table 4). The risk of pruritus depended on the injected opioid (Table 4); with epidural morphine, there was the maximum risk and with sufentanil citrate, the least risk. Ten trials (501 patients) reported on epidural-related technical problems; in 1 trial, the insertion level was lumbar, and in all others, it was thoracic. In 36 patients (7.2%), epidural analgesia had to be abandoned. In 2 trials, the incidence of failures was high, 12% and 15.8%; in the others, it varied between 3.9% and 7.4%. There was no relationship between the publication date of the trials and the rate of technical failures. There was no evidence of any effect of epidural analgesia on renal insufficiency, nausea or vomiting, or in-hospital mortality (Table 4).
COMMENT
In patients undergoing abdominal or thoracic surgery, epidural analgesia decreases the risk of postoperative pneumonia compared with systemic analgesia. Epidural analgesia also decreases the risk of prolonged ventilation or reintubation and improves some lung function parameters and blood oxygenation. The biological basis underlying these associations remains unclear; the improved outcome may be because of a better pain control with epidural analgesia, with subsequently enhanced respiratory function.
Although the beneficial effects of epidurals are numerous and well documented,1, 3, 5-7,78-79 the evidence of the usefulness of epidural analgesia for the prevention of postoperative pulmonary complications has been ambiguous. Previous meta-analyses have included limited relevant data9, 11 or have tested the effect of epidural analgesia in patients at low risk of pulmonary complications.5 For instance, the recently published systematic review on behalf of the American College of Physicians included only 6 trials compared with 58 in our analyses.11 This may reflect the fact that our literature search was more comprehensive and that our review focused on a specific intervention. Also, in the Urwin et al meta-analysis,5 data from 1200 patients undergoing hip fracture repair were included, and the incidence of pulmonary complications was about 5%. If we assume that epidural analgesia has the power of reducing the odds of pneumonia by 46% (OR, 0.54) (Table 1), then 3400 orthopedic patients are needed to be 95% confident to detect a significant difference in favor of epidural analgesia. We included more trials and more data than previous analyses, and we concentrated on patients at high risk for postoperative pulmonary complications.
Most other pulmonary outcome data may be regarded as surrogate. Atelectasis and respiratory depression were reported, but, as in similar analyses,80-81 definitions varied widely and made it impossible to pool the data. Pneumonia is perhaps the most important pulmonary outcome in this context since it may prolong duration of hospitalization and may lead to death.81-83
Although cardiac morbidity was not our primary end point, there was evidence that with epidurals, the incidence of myocardial infarction was decreased. The OR was similar to the Beattie et al analysis6 but we analyzed more data, and this may explain why our result was statistically significant. About 50 patients would need to receive an epidural to prevent an infarction in 1 of them. We do not know whether that protective effect is due to the epidural analgesia itself, to improved pain relief or arterial oxygenation, a combination of these factors, or yet another mechanism. We were unable to compare lumbar with thoracic epidurals, since most trials that reported on myocardial infarction tested thoracic epidurals.
Epidural analgesia is not without risk, although severe complications appear to be rare.84-87 One transient neurological injury in 1700 patients undergoing cardiothoracic surgery with epidural analgesia was estimated.87 In the trials included in our analysis, no severe complications were reported. However, no reporting of adverse events does not mean that none have occurred. Pruritus, although minor harm, was related to specific opioids. Some trials reported on technical failures; the combined estimate was very similar to previous analyses.2 The incidence of technical failures, implying that the attempt to provide postoperative pain relief with an epidural catheter has to be abandoned, has not changed during the last 35 years. This is not surprising since the technique has remained much the same.
The relative benefit of epidural analgesia has decreased over the last 3 decades. In the early 1970s, of 4 patients who received an epidural, 1 had no pneumonia postoperatively, which would have been the case had they all received conventional systemic analgesia. Thirty-five years later, this ratio has decreased to 1 in 25. The decrease in the protective effect of epidural analgesia compared with systematic analgesia does not seem to be related to a decrease in the efficacy of the epidurals per se but rather to a decrease in the baseline risk of pneumonia in patients who received systemic analgesia. The reason for this phenomenon is not obvious. The definition of pneumonia, although variable, has not changed over the years (Table 2). Other features of patient care, for instance, respiratory physiotherapy, the routine use of nasogastric tubes and prophylactic antibiotics, or early mobilization, may all have favorably influenced the baseline risk of pneumonia, although the impact of routine prophylactic respiratory physiotherapy on pulmonary complications after thoracic and abdominal surgery remains unproven.80-81 Also, any change in standard care would be expected to have an impact on the incidence of pneumonia with both epidural and systemic analgesia. A remarkable observation was the change in analgesia provided to controls. In trials published in the early 1970s, analgesia in controls was exclusively with subcutaneous on-demand opioids. In the 1980s, clinical practice changed to morphine infusions and the first PCA devices appeared. Since the 1990s, PCA and multimodal approaches with concomitant nonopioid analgesics became standard care. Patient-controlled analgesia with strong opioids may decrease the risk of pulmonary complications compared with conventional on-demand opioid administration.88 Indeed, in controls receiving PCA, the baseline risk of pneumonia was decreased, and this may explain why the relative impact of epidural analgesia in reducing the risk of pneumonia was lower (Table 1). However, even in trials that did not use PCA, a significant decrease in the baseline risk of pneumonia over time could be observed. Whether changes in standard-care analgesia had a direct impact on the incidence of postoperative pneumonia, or whether the decrease in the baseline risk reflects yet other changes in patient care, remains to be elucidated. Modification of standard care leading to changes in the baseline risk has been described in other settings.89-90 A change in the baseline risk may explain why, sometimes, meta-analyses and subsequently published large trials reach different conclusions.91 Those performing meta-analyses should be aware of this phenomenon when combining data from trials of different epochs that do not necessarily represent contemporary clinical practice. This does not mean that older trials should be excluded from meta-analysis, but the impact of changes in standard care on the efficacy of an experimental intervention should be explored in appropriate sensitivity analyses.
Our analysis has limitations. Some are related to problems that are inherent to meta-analyses. First, we cannot exclude that we missed trials, and some trials could not be included since data reporting was incomplete. Second, we did not analyze pain data since most trials did not report on such data. It has been shown before that epidural analgesia provided better pain relief than systemic analgesia.1 Third, the periods for sensitivity analyses were chosen arbitrarily and by convenience, although it is unlikely that different subgroups would have changed our findings. Fourth, we have taken definitions of outcomes as provided in the original trials. Finally, we chose the time of publication of a trial as an indicator of the age of that trial, although time of publication does not mean time of performance of a trial.
CONCLUSIONS
In patients undergoing abdominal or thoracic surgery, epidural analgesia is associated with a statistically significant and clinically relevant decrease in the risk of postoperative pneumonia, although the degree of efficacy has lessened over the last decades. That phenomenon is probably due to a decrease in the baseline risk of pneumonia. There is also evidence that pulmonary function and arterial oxygenation are improved with epidural analgesia and that the risk of myocardial infarction is reduced. Postoperative pain control with epidural analgesia is time-consuming, specific technical and pharmacological skills are needed, and professional surveillance of the patients must be guaranteed. Clearly, epidural analgesia is not without risk, and failures may occur. Our analyses provide an evidence base for rational decision making to ensure the most beneficial use of epidurals in surgical patients.
AUTHOR INFORMATION
Correspondence: Daniel M. Pöpping, MD, Klinik für Anästhesiologie und Intensivmedizin, Universitätsklinikum, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany (poppind{at}uni-muenster.de).
Accepted for Publication: May 8, 2007.
Author Contributions: Dr Tramèr had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Pöpping, Marret, and Tramèr. Acquisition of data: Pöpping, Marret, and Remy. Analysis and interpretation of data: Pöpping, Elia, and Tramèr. Drafting of the manuscript: Pöpping, Elia, and Tramèr. Critical revision of the manuscript for important intellectual content: Pöpping, Elia, Marret, Remy, and Tramèr. Statistical analysis: Pöpping, Elia, and Tramèr. Obtained funding: Tramèr. Administrative, technical, and material support: Pöpping and Tramèr. Study supervision: Tramèr.
Financial Disclosure: None reported.
Funding/Support: The study was partially funded by a grant from UPSA (France), a Bristol-Myers Squibb company. Dr Elia's salary was paid by the EBCAP foundation (http://www.hcuge.ch/anesthesie/ebcap.htm).
Role of the Sponsor: The sponsor was not involved in the design or conduct of the study; collection, management, analysis, or interpretation of the data; or preparation, review, or approval of the manuscript. The sponsor solely provided funds for travel, meetings, and translations of non-English papers.
Additional Contributions: Special thanks go to Michael F. M. James, PhD, FRCA, Dr Per Flisberg, Christian Jayr, PD, Bernd Wiedemann, PD, Dr Shahnaz Christina Azad, and Dr Adrianus J. de Vries, who responded to our inquiries. 4T Traduction (Levallois-Perret, France) translated 6 Turkish, Japanese, Chinese, or Spanish papers into English.
Author Affiliations: Department of Anesthesiology and Intensive Care, University Hospital Münster, Münster, Germany (Dr Pöpping); Department of Anesthesia and Intensive Care, Tenon University Hospital, Assistance Publique–Hôpitaux de Paris, Paris, France (Drs Marret and Remy); and Division of Anesthesiology, University Hospitals of Geneva, Geneva, Switzerland (Dr Elia and Prof Tramèr).
REFERENCES
| |
1. Block BM, Liu SS, Rowlingson AJ, Cowan AR, Cowan JA Jr, Wu CL. Efficacy of postoperative epidural analgesia: a meta-analysis. JAMA. 2003;290(18):2455-2463.
FREE FULL TEXT
2. Dolin SJ, Cashman JN, Bland JM. Effectiveness of acute postoperative pain management, I: evidence from published data. Br J Anaesth. 2002;89(3):409-423.
FREE FULL TEXT
3. Liu S, Carpenter RL, Neal JM. Epidural anesthesia and analgesia: their role in postoperative outcome. Anesthesiology. 1995;82(6):1474-1506.
FULL TEXT
|
ISI
| PUBMED
4. Rigg JR. Does regional block improve outcome after surgery? Anaesth Intensive Care. 1991;19(3):404-411.
ISI
| PUBMED
5. Urwin SC, Parker MJ, Griffiths R. General versus regional anaesthesia for hip fracture surgery: a meta-analysis of randomized trials. Br J Anaesth. 2000;84(4):450-455.
FREE FULL TEXT
6. Beattie WS, Badner NH, Choi P. Epidural analgesia reduces postoperative myocardial infarction: a meta-analysis. Anesth Analg. 2001;93(4):853-858.
FREE FULL TEXT
7. Guay J. The benefits of adding epidural analgesia to general anesthesia: a metaanalysis. J Anesth. 2006;20(4):335-340.
FULL TEXT
| PUBMED
8. Liu SS, Block BM, Wu CL. Effects of perioperative central neuraxial analgesia on outcome after coronary artery bypass surgery: a meta-analysis. Anesthesiology. 2004;101(1):153-161.
FULL TEXT
|
ISI
| PUBMED
9. Ballantyne JC, Carr DB, deFerranti S; et al. The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. Anesth Analg. 1998;86(3):598-612.
ABSTRACT
10. Rodgers A, Walker N, Schug S; et al. Reduction of postoperative mortality and morbidity with epidural or spinal anaesthesia: results from overview of randomised trials. BMJ. 2000;321(7275):1493.
FREE FULL TEXT
11. Lawrence VA, Cornell JE, Smetana GW. Strategies to reduce postoperative pulmonary complications after noncardiothoracic surgery: systematic review for the American College of Physicians. Ann Intern Med. 2006;144(8):596-608.
FREE FULL TEXT
12. Qaseem A, Snow V, Fitterman N; et al. Risk assessment for and strategies to reduce perioperative pulmonary complications for patients undergoing noncardiothoracic surgery: a guideline from the American College of Physicians. Ann Intern Med. 2006;144(8):575-580.
FREE FULL TEXT
13. de Vries AJ, Mariani MA, van der Maaten JM, Loef BG, Lip H. To ventilate or not after minimally invasive direct coronary artery bypass surgery: the role of epidural anesthesia. J Cardiothorac Vasc Anesth. 2002;16(1):21-26.
FULL TEXT
|
ISI
| PUBMED
14. Flisberg P, Tornebrandt K, Walther B, Lundberg J. Pain relief after esophagectomy: thoracic epidural analgesia is better than parenteral opioids. J Cardiothorac Vasc Anesth. 2001;15(3):282-287.
FULL TEXT
|
ISI
| PUBMED
15. James MF, Heijke SA, Gordon PC. Intravenous tramadol versus epidural morphine for postthoracotomy pain relief: a placebo-controlled double-blind trial. Anesth Analg. 1996;83(1):87-91.
ABSTRACT
16. Tramèr MR, Walder B. Number needed to treat (or harm). World J Surg. 2005;29(5):576-581.
FULL TEXT
|
ISI
| PUBMED
17. Azad SC, Groh J, Beyer A, Schneck D, Dreher E, Peter K. Continuous epidural analgesia versus patient-controlled intravenous analgesia for postthoracotomy pain. Acute Pain. 2000;3(2):14-23.
FULL TEXT
18. Azad SC, Groh J, Beyer A, Schneck D, Dreher E, Peter K. Continuous peridural analgesia vs patient-controlled intravenous analgesia for pain therapy after thoracotomy [in German]. Anaesthesist. 2000;49(1):9-17.
FULL TEXT
|
ISI
| PUBMED
19. Scott NB, Mogensen T, Bigler D, Kehlet H. Comparison of the effects of continuous intrapleural vs epidural administration of 0.5% bupivacaine on pain, metabolic response and pulmonary function following cholecystectomy. Acta Anaesthesiol Scand. 1989;33(7):535-539.
ISI
| PUBMED
20. Scott NB, Mogensen T, Bigler D, Lund C, Kehlet H. Continuous thoracic extradural 0.5% bupivacaine with or without morphine: effect on quality of blockade, lung function and the surgical stress response. Br J Anaesth. 1989;62(3):253-257.
FREE FULL TEXT
21. Stenseth R, Berg EM, Bjella L, Christensen O, Levang OW, Gisvold SE. Effects of thoracic epidural analgesia on coronary hemodynamics and myocardial metabolism in coronary artery bypass surgery. J Cardiothorac Vasc Anesth. 1995;9(5):503-509.
FULL TEXT
|
ISI
| PUBMED
22. Stenseth R, Bjella L, Berg EM, Christensen O, Levang OW, Gisvold SE. Thoracic epidural analgesia in aortocoronary bypass surgery, I: haemodynamic effects. Acta Anaesthesiol Scand. 1994;38(8):826-833.
ISI
| PUBMED
23. Addison NV, Brear FA, Budd K, Whittaker M. Epidural analgesia following cholecystectomy. Br J Surg. 1974;61(10):850-852.
ISI
| PUBMED
24. Asuero de Lis MS, Navarro Serrano M, Rubial Alvarez M, Perez Pena J, Molins Gauna N. Effects of postoperative pain on lung volume in patients undergoing aortic surgery [in Spanish]. Rev Esp Anestesiol Reanim. 1990;37(1):15-18.
PUBMED
25. Baxter AD, Laganiere S, Samson B, Stewart J, Hull K, Goernert L. A comparison of lumbar epidural and intravenous fentanyl infusions for post-thoracotomy analgesia. Can J Anaesth. 1994;41(3):184-191.
ISI
| PUBMED
26. Benzon HT, Wong HY, Belavic AM Jr; et al. A randomized double-blind comparison of epidural fentanyl infusion versus patient-controlled analgesia with morphine for postthoracotomy pain. Anesth Analg. 1993;76(2):316-322.
ISI
| PUBMED
27. Boisseau N, Rabary O, Padovani B; et al. Improvement of ‘dynamic analgesia’ does not decrease atelectasis after thoracotomy. Br J Anaesth. 2001;87(4):564-569.
FREE FULL TEXT
28. Boylan JF, Katz J, Kavanagh BP; et al. Epidural bupivacaine-morphine analgesia versus patient-controlled analgesia following abdominal aortic surgery: analgesic, respiratory, and myocardial effects. Anesthesiology. 1998;89(3):585-593.
FULL TEXT
|
ISI
| PUBMED
29. Broekema AA, Veen A, Fidler V, Gielen MJ, Hennis PJ. Postoperative analgesia with intramuscular morphine at fixed rate versus epidural morphine or sufentanil and bupivacaine in patients undergoing major abdominal surgery. Anesth Analg. 1998;87(6):1346-1353.
FREE FULL TEXT
30. Carli F, Mayo N, Klubien K, Schricker T, Trudel J, Belliveau P. Epidural analgesia enhances functional exercise capacity and health-related quality of life after colonic surgery: results of a randomized trial. Anesthesiology. 2002;97(3):540-549.
FULL TEXT
|
ISI
| PUBMED
31. Carli F, Trudel JL, Belliveau P. The effect of intraoperative thoracic epidural anesthesia and postoperative analgesia on bowel function after colorectal surgery: a prospective, randomized trial. Dis Colon Rectum. 2001;44(8):1083-1089.
FULL TEXT
|
ISI
| PUBMED
32. Chauvin M, Hongnat JM, Mourgeon E, Lebrault C, Bellenfant F, Alfonsi P. Equivalence of postoperative analgesia with patient-controlled intravenous or epidural alfentanil. Anesth Analg. 1993;76(6):1251-1258.
ISI
| PUBMED
33. Cullen ML, Staren ED, el-Ganzouri A, Logas WG, Ivankovich AD, Economou SG. Continuous epidural infusion for analgesia after major abdominal operations: a randomized, prospective, double-blind study. Surgery. 1985;98(4):718-728.
ISI
| PUBMED
34. Cuschieri RJ, Morran CG, Howie JC, McArdle CS. Postoperative pain and pulmonary complications: comparison of three analgesic regimens. Br J Surg. 1985;72(6):495-498.
ISI
| PUBMED
35. Dahl JB, Hjortso NC, Stage JG; et al. Effects of combined perioperative epidural bupivacaine and morphine, ibuprofen, and incisional bupivacaine on postoperative pain, pulmonary, and endocrine-metabolic function after minilaparotomy cholecystectomy. Reg Anesth. 1994;19(3):199-205.
ISI
| PUBMED
36. Davies MJ, Silbert BS, Mooney PJ, Dysart RH, Meads AC. Combined epidural and general anaesthesia versus general anaesthesia for abdominal aortic surgery: a prospective randomised trial. Anaesth Intensive Care. 1993;21(6):790-794.
ISI
| PUBMED
37. Della Rocca G, Coccia C, Pompei L; et al. Post-thoracotomy analgesia: epidural vs intravenous morphine continuous infusion. Minerva Anestesiol. 2002;68(9):681-693.
PUBMED
38. Garnett RL, MacIntyre A, Lindsay P; et al. Perioperative ischaemia in aortic surgery: combined epidural/general anaesthesia and epidural analgesia vs general anaesthesia and i.v. analgesia. Can J Anaesth. 1996;43(8):769-777.
ISI
| PUBMED
39. Grant RP, Dolman JF, Harper JA; et al. Patient-controlled lumbar epidural fentanyl compared with patient-controlled intravenous fentanyl for post-thoracotomy pain. Can J Anaesth. 1992;39(3):214-219.
ISI
| PUBMED
40. Guinard JP, Mavrocordatos P, Chiolero R, Carpenter RL. A randomized comparison of intravenous versus lumbar and thoracic epidural fentanyl for analgesia after thoracotomy. Anesthesiology. 1992;77(6):1108-1115.
ISI
| PUBMED
41. Hansdottir V, Philip J, Olsen MF, Eduard C, Houltz E, Ricksten SE. Thoracic epidural versus intravenous patient-controlled analgesia after cardiac surgery: a randomized controlled trial on length of hospital stay and patient-perceived quality of recovery. Anesthesiology. 2006;104(1):142-151.
FULL TEXT
|
ISI
| PUBMED
42. Hasenbos M, van Egmond J, Gielen M, Crul JF. Post-operative analgesia by epidural versus intramuscular nicomorphine after thoracotomy: part I. Acta Anaesthesiol Scand. 1985;29(6):572-576.
ISI
| PUBMED
43. Hendolin H, Lahtinen J, Lansimies E, Tuppurainen T, Partanen K. The effect of thoracic epidural analgesia on respiratory function after cholecystectomy. Acta Anaesthesiol Scand. 1987;31(7):645-651.
ISI
| PUBMED
44. Hjortsø NC, Neumann P, Frosig F; et al. A controlled study on the effect of epidural analgesia with local anaesthetics and morphine on morbidity after abdominal surgery. Acta Anaesthesiol Scand. 1985;29(8):790-796.
ISI
| PUBMED
45. Jayr C, Beaussier M, Gustafsson U; et al. Continuous epidural infusion of ropivacaine for postoperative analgesia after major abdominal surgery: comparative study with i.v. PCA morphine. Br J Anaesth. 1998;81(6):887-892.
FREE FULL TEXT
46. Jayr C, Mollie A, Bourgain JL; et al. Postoperative pulmonary complications: general anesthesia with postoperative parenteral morphine compared with epidural analgesia. Surgery. 1988;104(1):57-63.
ISI
| PUBMED
47. Jayr C, Thomas H, Rey A, Farhat F, Lasser P, Bourgain JL. Postoperative pulmonary complications: epidural analgesia using bupivacaine and opioids versus parenteral opioids. Anesthesiology. 1993;78(4):666-676, discussion 622A.
ISI
| PUBMED
48. Kilbride MJ, Senagore AJ, Mazier WP, Ferguson C, Ufkes T. Epidural analgesia. Surg Gynecol Obstet. 1992;174(2):137-140.
ISI
| PUBMED
49. Liem TH, Hasenbos MA, Booij LH, Gielen MJ. Coronary artery bypass grafting using two different anesthetic techniques, part 2: postoperative outcome. J Cardiothorac Vasc Anesth. 1992;6(2):156-161.
FULL TEXT
| PUBMED
50. Logas WG, el-Baz N, el-Ganzouri A; et al. Continuous thoracic epidural analgesia for postoperative pain relief following thoracotomy: a randomized prospective study. Anesthesiology. 1987;67(5):787-791.
ISI
| PUBMED
51. Mann C, Pouzeratte Y, Boccara G; et al. Comparison of intravenous or epidural patient-controlled analgesia in the elderly after major abdominal surgery. Anesthesiology. 2000;92(2):433-441.
FULL TEXT
|
ISI
| PUBMED
52. Miller L, Gertel M, Fox GS, MacLean LD. Comparison of effect of narcotic and epidural analgesia on postoperative respiratory function. Am J Surg. 1976;131(3):291-294.
FULL TEXT
|
ISI
| PUBMED
53. Norris EJ, Beattie C, Perler BA; et al. Double-masked randomized trial comparing alternate combinations of intraoperative anesthesia and postoperative analgesia in abdominal aortic surgery. Anesthesiology. 2001;95(5):1054-1067.
FULL TEXT
|
ISI
| PUBMED
54. Park WY, Thompson JS, Lee KK. Effect of epidural anesthesia and analgesia on perioperative outcome: a randomized, controlled Veterans Affairs cooperative study. Ann Surg. 2001;234(4):560-569, discussion 569-571.
FULL TEXT
|
ISI
| PUBMED
55. Peyton PJ, Myles PS, Silbert BS, Rigg JA, Jamrozik K, Parsons R. Perioperative epidural analgesia and outcome after major abdominal surgery in high-risk patients. Anesth Analg. 2003;96(2):548.
FREE FULL TEXT
56. Pflug AE, Murphy TM, Butler SH, Tucker GT. The effects of postoperative peridural analgesia on pulmonary therapy and pulmonary complications. Anesthesiology. 1974;41(1):8-17.
ISI
| PUBMED
57. Priestley MC, Cope L, Halliwell R; et al. Thoracic epidural anesthesia for cardiac surgery: the effects on tracheal intubation time and length of hospital stay. Anesth Analg. 2002;94(2):275-282.
FREE FULL TEXT
58. Rosenberg PH, Heino A, Scheinin B. Comparison of intramuscular analgesia, intercostal block, epidural morphine and on-demand-i.v.-fentanyl in the control of pain after upper abdominal surgery. Acta Anaesthesiol Scand. 1984;28(6):603-607.
ISI
| PUBMED
59. Royse C, Royse A, Soeding P, Blake D, Pang J. Prospective randomized trial of high thoracic epidural analgesia for coronary artery bypass surgery. Ann Thorac Surg. 2003;75(1):93-100.
FREE FULL TEXT
60. Salomäki TE, Laitinen JO, Nuutinen LS. A randomized double-blind comparison of epidural versus intravenous fentanyl infusion for analgesia after thoracotomy. Anesthesiology. 1991;75(5):790-795.
FULL TEXT
|
ISI
| PUBMED
61. Scheinin B, Asantila R, Orko R. The effect of bupivacaine and morphine on pain and bowel function after colonic surgery. Acta Anaesthesiol Scand. 1987;31(2):161-164.
ISI
| PUBMED
62. Schulze S, Roikjaer O, Hasselstrom L, Jensen NH, Kehlet H. Epidural bupivacaine and morphine plus systemic indomethacin eliminates pain but not systemic response and convalescence after cholecystectomy. Surgery. 1988;103(3):321-327.
ISI
| PUBMED
63. Scott NB, Turfrey DJ, Ray DA; et al. A prospective randomized study of the potential benefits of thoracic epidural anesthesia and analgesia in patients undergoing coronary artery bypass grafting. Anesth Analg. 2001;93(3):528-535.
FREE FULL TEXT
64. Seeling W, Lotz P, Schroder M. Postoperative pulmonary function following abdominal surgery: comparison of continuous, segmental thoracic peridural anesthesia and intramuscular piritramide injections [in German]. Anaesthesist. 1984;33(9):408-416.
ISI
| PUBMED
65. Shulman M, Sandler AN, Bradley JW, Young PS, Brebner J. Postthoracotomy pain and pulmonary function following epidural and systemic morphine. Anesthesiology. 1984;61(5):569-575.
ISI
| PUBMED
66. Spence AA, Smith G. Postoperative analgesia and lung function: a comparison of morphine with extradural block. Br J Anaesth. 1971;43(2):144-148.
FREE FULL TEXT
67. Stenseth R, Bjella L, Berg EM, Christensen O, Levang OW, Gisvold SE. Effects of thoracic epidural analgesia on pulmonary function after coronary artery bypass surgery. Eur J Cardiothorac Surg. 1996;10(10):859-865, discussion 866.
ABSTRACT
68. Tang LY, Cao DX, Luo HY, Gao CS. The effects of postoperative epidural analgesia on pulmonary function after upper abdominal surgery in geriatric patients [in Chinese]. Zhonghua Mazuixue Zazhi. 1995;15(4):292-294.
69. Tenling A, Joachimsson PO, Tyden H, Hedenstierna G. Thoracic epidural analgesia as an adjunct to general anaesthesia for cardiac surgery: effects on pulmonary mechanics. Acta Anaesthesiol Scand. 2000;44(9):1071-1076.
FULL TEXT
|
ISI
| PUBMED
70. Tenling A, Joachimsson PO, Tyden H, Wegenius G, Hedenstierna G. Thoracic epidural anesthesia as an adjunct to general anesthesia for cardiac surgery: effects on ventilation-perfusion relationships. J Cardiothorac Vasc Anesth. 1999;13(3):258-264.
FULL TEXT
|
ISI
| PUBMED
71. Tsui SL, Chan CS, Chan AS, Wong SJ, Lam CS, Jones RD. Postoperative analgesia for oesophageal surgery: a comparison of three analgesic regimens. Anaesth Intensive Care. 1991;19(3):329-337.
ISI
| PUBMED
72. Tuman KJ, McCarthy RJ, March RJ, DeLaria GA, Patel RV, Ivankovich AD. Effects of epidural anesthesia and analgesia on coagulation and outcome after major vascular surgery. Anesth Analg. 1991;73(6):696-704.
FREE FULL TEXT
73. Welch JP, Cohen JL, Vignati PV, Allen LW, Morrow JS, Carter JJ. Pain control following elective gastrointestinal surgery: is epidural anesthesia warranted? Conn Med. 1998;62(8):461-464.
PUBMED
74. Xue Z-G, Bai L, Jiang H. Combined epidural block with general anesthesia in patients with chronic obstructive pulmonary disease. J Shanghai Medical University. 2000;27(2):302-305, 323.
75. Yeager MP, Glass DD, Neff RK, Brinck-Johnsen T. Epidural anesthesia and analgesia in high-risk surgical patients. Anesthesiology. 1987;66(6):729-736.
ISI
| PUBMED
76. Yilmazlar A, Uckunkaya N, Sahin S, Yilmazlar T, Zorluoglu A. The efficacy of postoperative analgesia in abdominal surgery. Agri Dergisi. 1995;7(1):11-15.
77. Zwarts SJ, Hasenbos MA, Gielen MJ, Kho HG. The effect of continuous epidural analgesia with sufentanil and bupivacaine during and after thoracic surgery on the plasma cortisol concentration and pain relief. Reg Anesth. 1989;14(4):183-188.
ISI
| PUBMED
78. Rigg JR, Jamrozik K, Myles PS; et al. Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. Lancet. 2002;359(9314):1276-1282.
FULL TEXT
|
ISI
| PUBMED
79. Wu CL, Cohen SR, Richman JM; et al. Efficacy of postoperative patient-controlled and continuous infusion epidural analgesia versus intravenous patient-controlled analgesia with opioids: a meta-analysis. Anesthesiology. 2005;103(5):1079-1088, quiz 1109-1010.
FULL TEXT
|
ISI
| PUBMED
80. Pasquina P, Tramèr MR, Granier JM, Walder B. Respiratory physiotherapy to prevent pulmonary complications after abdominal surgery: a systematic review. Chest. 2006;130(6):1887-1899.
FREE FULL TEXT
81. Pasquina P, Tramèr MR, Walder B. Prophylactic respiratory physiotherapy after cardiac surgery: systematic review. BMJ. 2003;327(7428):1379.
FREE FULL TEXT
82. Arozullah AM, Khuri SF, Henderson WG, Daley J. Development and validation of a multifactorial risk index for predicting postoperative pneumonia after major noncardiac surgery. Ann Intern Med. 2001;135(10):847-857.
FREE FULL TEXT
83. Hulzebos EH, Helders PJ, Favie NJ, De Bie RA, Brutel de la Riviere A, Van Meeteren NL. Preoperative intensive inspiratory muscle training to prevent postoperative pulmonary complications in high-risk patients undergoing CABG surgery: a randomized clinical trial. JAMA. 2006;296(15):1851-1857.
FREE FULL TEXT
84. Aromaa U, Lahdensuu M, Cozanitis DA. Severe complications associated with epidural and spinal anaesthesias in Finland 1987-1993: a study based on patient insurance claims. Acta Anaesthesiol Scand. 1997;41(4):445-452.
ISI
| PUBMED
85. Auroy Y, Narchi P, Messiah A, Litt L, Rouvier B, Samii K. Serious complications related to regional anesthesia: results of a prospective survey in France. Anesthesiology. 1997;87(3):479-486.
FULL TEXT
|
ISI
| PUBMED
86. Kindler CH, Seeberger MD, Staender SE. Epidural abscess complicating epidural anesthesia and analgesia: an analysis of the literature. Acta Anaesthesiol Scand. 1998;42(6):614-620.
ISI
| PUBMED
87. Ruppen W, Derry S, McQuay HJ, Moore RA. Incidence of epidural haematoma and neurological injury in cardiovascular patients with epidural analgesia/anaesthesia: systematic review and meta-analysis. BMC Anesthesiol. 2006;6:10.
FULL TEXT
| PUBMED
88. Walder B, Schafer M, Henzi I, Tramèr MR. Efficacy and safety of patient-controlled opioid analgesia for acute postoperative pain: a quantitative systematic review. Acta Anaesthesiol Scand. 2001;45(7):795-804.
ISI
| PUBMED
89. Babaev A, Frederick PD, Pasta DJ, Every N, Sichrovsky T, Hochman JS. Trends in management and outcomes of patients with acute myocardial infarction complicated by cardiogenic shock. JAMA. 2005;294(4):448-454.
FREE FULL TEXT
90. Miyasaka Y, Barnes ME, Gersh BJ; et al. Time trends of ischemic stroke incidence and mortality in patients diagnosed with first atrial fibrillation in 1980 to 2000: report of a community-based study. Stroke. 2005;36(11):2362-2366.
FREE FULL TEXT
91. LeLorier J, Gregoire G, Benhaddad A, Lapierre J, Derderian F. Discrepancies between meta-analyses and subsequent large randomized, controlled trials. N Engl J Med. 1997;337(8):536-542.
FREE FULL TEXT
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati  Twitter
What's this?
RELATED ARTICLE
Protective Effects of Epidural Analgesia on Pulmonary Complications After Abdominal and Thoracic Surgery—Invited Critique
William T. Merritt and Michael Marohn
Arch Surg. 2008;143(10):1000.
EXTRACT
| FULL TEXT
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES
Perioperative Epidural Analgesia and Prevention of Ventilator-Associated Pneumonia
Tornero-Campello
Chest 2009;136:322-322.
FULL TEXT
|
Fewer than 10 patients per treatment group. 
Duration of epidural analgesia only intraoperatively or less than 24 hours postoperatively. ||Continuous data presented as means but without standard deviation, no dichotomous data. RCT indicates randomized controlled trial.
