Effects of perioperative central neuraxial analgesia on outcome after coronary artery bypass surgery: a meta-analysis

Effect of Postoperative Analgesia on Major Postoperative Complications: A Systematic Update of the Evidence

BACKGROUND

Few individual clinical trials have had sufficient subject numbers to definitively determine the effects of postoperative analgesia on major outcomes.

METHODS

We systematically searched the Medline and the Cochrane Library databases for the past decade and focused on meta-analyses and large, randomized, controlled trials.

RESULTS

Eighteen meta-analyses, 10 systematic reviews, 8 additional randomized, controlled trials, and 2 observational database articles were identified for review or comment. Epidural analgesia with local anesthetics has the greatest theoretical potential to affect major outcomes and has been the most thoroughly investigated technique. The majority of evidence favors an ability of epidural analgesia to reduce postoperative cardiovascular and pulmonary complications only after major vascular surgery or in high-risk patients. This finding may become irrelevant because of rapid conversion of major surgery to minimally invasive techniques (e.g., endoluminal abdominal aortic repair) that carry less risk of complications. There is also consistent evidence that epidural analgesia with local anesthetics is associated with faster resolution of postoperative ileus after major abdominal surgery. Again, this finding may also become irrelevant with the adoption of laparoscopic techniques and multimodal fast-track programs for abdominal surgery. There is no current evidence that perineural analgesia, continuous wound catheters using local anesthetics, IV patient-controlled analgesia with opioids, or addition of multimodal systemic analgesics have any clinically significant beneficial effect on postoperative complications.

CONCLUSIONS

Overall, there is insufficient evidence to confirm or deny the ability of postoperative analgesic techniques to affect major postoperative mortality or morbidity. This is primarily due to typically insufficient subject numbers to detect differences in currently low incidences of postoperative complications.

Postoperative pain management and outcome after surgery

Postoperative pain management aims not only to decrease pain intensity but also to increase patient comfort and to improve postoperative outcome. Better pain control is achieved through a multimodal combination of regional analgesic techniques and systemic administration of analgesic agents. To guarantee uneventful follow-up and unnecessary prolongation of hospital stay, it is important to avoid side-effects of analgesic agents, especially those of opioids which are dose-related, by decreasing opioid demand through combination with non-opioid agents. Epidural analgesia not only has the advantage of providing potent and effective analgesia but also of hastening recovery of bowel function and facilitating physiotherapy and rehabilitation. Unfortunately, a reduction in postoperative morbidity and mortality by epidural analgesia has not actually been demonstrated. Inclusion of postoperative pain treatment in a multimodal approach of patient rehabilitation may improve recovery and shorten hospital stay. Effective treatment of postoperative pain is also likely to prevent chronic pain syndrome after surgery, but further studies are needed to support this hypothesis.

Regional anaesthesia and perioperative outcome

PURPOSE OF REVIEW

The ongoing debate on the outcome benefits of regional anaesthesia and analgesia over general anaesthesia and systemic analgesia has led to a large number of recently published papers, in particular systematic reviews and meta-analyses that justify a review of the current status of the debate.

RECENT FINDINGS

Meta-analyses have shown consistently improved analgesia with epidural techniques, but the results are by far less consistent with regard to other outcomes, in particular morbidity and mortality. Specific outcomes in specific types of surgery, however, such as bowel recovery after abdominal surgery, can be improved by neuraxial blockade, which also remains the technique of choice for obstetric analgesia and anaesthesia. In certain indications, peripheral nerve blocks may have the potential to replace neuraxial blocks while maintaining the benefits of the regional technique, such as paravertebral blocks for thoracotomies.

SUMMARY

Although there are a considerable number of recent publications on the topic, the complex issues around the effect of regional anaesthesia on outcome is not completely resolved, possibly because the data are often not procedure specific. In addition, however, it may be that our current literature cannot provide a definitive answer.

The influence of new antithrombotic drugs on regional anesthesia

PURPOSE OF REVIEW

Antithrombotic drugs are known to increase the risk of spinal epidural hematoma after neuraxial blockade. During the last few years, several new anticoagulants have been introduced, some of them more potent than the drugs currently available. More potency, however, may also indicate a higher risk of bleeding.

RECENT FINDINGS

Case series from the last few years indicate that spinal epidural hematoma is more common then previously estimated, with a prevalence from 1: 100,000 in obstetric patients to as high as 1: 3,600 in female orthopedic patients. In order to diminish this risk, most national societies have issued guidelines in which time intervals were established between administration of antithrombotic drugs and performance of neuraxial blockade.

SUMMARY

Guidelines are perceived to be capable of reducing the incidence of spinal epidural hematoma with the inherent risk of permanent paraplegia. These guidelines, however, will only be a valuable aid for clinicians if they are constantly updated and newer antithrombotic drugs are included. Although the resurge of peripheral nerve blocks may diminish patient hazards, deep nerve blocks such as lumbar sympathetic blockade are not devoid of serious complications and should probably be handled in the same way as neuraxial blockade.

Monitorización del dolor. Recomendaciones del grupo de trabajo de analgesia y sedación de la SEMICYUC

In critically ill patients, pain is frequently underestimated and so insufficiently managed. Psychological, haemodynamic and neuroendocrine responses, secondary to untreated pain, could produce morbidity and even increases in patient mortality. All members of the intensive care team must have abilities to assess and to manage pain. The evaluation of pain in the critically ill patient is very difficult but extremely important. Self-reported pain is the starting point for treatment. The pain scores recommended are, VAS (visual analogue scale) and NRS (numeric rating scale) in communicative patients and Campbell scale in uncommunicative patients. Adequate and regular patient assessment leads to improved pain control. Scores higher than 3 points should not be permitted. A pain-free Intensive Care Unit should be a quality standard healthcare aim.

Effect of postoperative epidural analgesia on morbidity and mortality after lung resection in Medicare patients

STUDY OBJECTIVE

To perform an analysis of the Medicare claims database in patients undergoing lung resection to determine whether there is an association between postoperative epidural analgesia and mortality.

DESIGN

Retrospective cohort (database) design.

SETTING

University hospital.

MEASUREMENTS

We examined a cohort of 3501 patients obtained from a 5% nationally random sample of 1997 to 2001 Medicare beneficiaries who underwent nonemergency segmental excision of the lung (International Classification of Diseases, 9th Revision, Clinical Modification codes 32.3 and 32.4). Patient data were divided into two groups depending on the presence or absence of billing for postoperative epidural analgesia (Current Procedural Terminology code 01996). The primary outcomes assessed were death at 7 and 30 days after the procedure. The rates of major morbidity (acute myocardial infarction, angina, cardiac dysrhythmias, heart failure, pneumonia, pulmonary edema, respiratory failure, deep venous thrombosis, pulmonary embolism, sepsis, acute renal failure, somnolence, acute cerebrovascular event, transient organic syndrome, and paralytic ileus) were also compared. Multivariate regression analysis incorporating race, gender, age, comorbidities, hospital size, hospital teaching status, and hospital technology status was performed to determine whether the presence of postoperative epidural analgesia had an independent effect on mortality or major morbidity.

MAIN RESULTS

Multivariate regression analysis showed that the presence of epidural analgesia was associated with a significantly lower odds of death at 7 days (odds ratio, 0.39; 95% confidence interval, 0.19-0.80; P = 0.001) and 30 days (odds ratio, 0.53; 95% confidence interval, 0.35-0.78; P = 0.002) after surgery. There was no difference between the groups with regard to overall major morbidity.

CONCLUSIONS

Postoperative epidural analgesia may contribute to lower odds of death after segmental excision of the lung, although the mechanism of such a benefit is not clear from our analysis.

The benefits of adding epidural analgesia to general anesthesia: a metaanalysis

The purpose of this metaanalysis was to determine the benefits of postoperative epidural analgesia in patients operated on under general anesthesia. By searching the American National Library of Medicine's Pubmed database from 1966 to July 10, 2004, 70 studies were identified. These included 5402 patients, of which 2660 had had epidural analgesia. Epidural analgesia reduces the incidence of arrhythmia, odds ratio (OR) = 0.59 (95%CI = 0.42, 0.81, P = 0.001); time to tracheal extubation, OR = -3.90 h (95%CI = -6.37, -1.42, P = 0.002); intensive care unit stay, OR = -2.94 h (95%CI = -5.66, -0.22, P = 0.03); visual analogical pain (VAS) scores at rest, OR = -0.78 (95%CI = -0.99, -0.57, P < 0.00001) and during movement, OR = -1.28 (95%CI = -1.81, -0.75, P < 0.00001); maximal blood epinephrine, OR = -165.70 pg.ml(-1) (95%CI = -252.18, -79.23, P = 0.0002); norepinephrine, OR = -134.24 pg.ml(-1) (95%CI = -247.92, -20.57, P = 0.02); cortisol, OR = -55.81 nmol.l(-1) (95%CI = -79.28, -32.34, P < 0.00001); and glucose concentrations achieved, OR = -0.87 nmol.l(-1) (95%CI = -1.37, -0.37, P = 0.0006). It also reduces the first 24-h morphine consumption, OR = -13.62 mg (95%CI = -22.70, -4.54, P = 0.003), and improves the forced vital capacity (FVC), OR = 0.23 l (95%CI = 0.09, 0.37, P = 0.001) at 24 h. A thoracic epidural containing a local anesthetic reduces the incidence of renal failure: OR = 0.34 (95%CI = 0.14, 0.81, P = 0.01). Epidural analgesia may thus offer many advantages over other modes of postoperative analgesia.

Incidence of epidural haematoma and neurological injury in cardiovascular patients with epidural analgesia/anaesthesia: systematic review and meta-analysis

Background

Epidural anaesthesia is used extensively for cardiothoracic and vascular surgery in some centres, but not in others, with argument over the safety of the technique in patients who are usually extensively anticoagulated before, during, and after surgery. The principle concern is bleeding in the epidural space, leading to transient or persistent neurological problems.

Methods

We performed an extensive systematic review to find published cohorts of use of epidural catheters during vascular, cardiac, and thoracic surgery, using electronic searching, hand searching, and reference lists of retrieved articles.

Results

Twelve studies included 14,105 patients, of whom 5,026 (36%) had vascular surgery, 4,971 (35%) cardiac surgery, and 4,108 (29%) thoracic surgery. There were no cases of epidural haematoma, giving maximum risks following epidural anaesthesia in cardiac, thoracic, and vascular surgery of 1 in 1,700, 1 in 1,400 and 1 in 1,700 respectively. In all these surgery types combined the maximum expected rate would be 1 in 4,700. In all these patients combined there were eight cases of transient neurological injury, a rate of 1 in 1,700 (95% confidence interval 1 in 3,300 to 1 in 850). There were no cases of persistent neurological injury (maximum expected rate 1 in 4,600).

Conclusion

These estimates for cardiothoracic epidural anaesthesia should be the worst case. Limitations are inadequate denominators for different types of surgery in anticoagulated cardiothoracic or vascular patients more at risk of bleeding.

Epidural catheter placement in children: comparing a novel approach using ultrasound guidance and a standard loss-of-resistance technique

BACKGROUND

We report a prospective, randomized study to evaluate ultrasound guidance for epidural catheter placement in children 0-6 yr of age.

METHODS

Epidural catheters were placed at lumbar or thoracic cord levels in 64 children undergoing major surgery, using either ultrasonography or loss-of-resistance (LOR) for guidance. Using a 5-10 MHz linear ultrasound probe, the neuraxial structures were identified, the skin-epidural depth and epidural space was measured, the advancing epidural catheter visualized, and the spread of local anaesthetic verifying catheter position was confirmed. Epidural placement procedures were analysed for bone contacts and speed of execution. Children under 6 months were analysed separately.

RESULTS

Epidural placement involved bone contacts in 17% of children in the ultrasound group and 71% of children in the LOR group (P<0.0001). Epidurals were executed more swiftly in the ultrasound group [162 (75) s vs 234 (138) s; P<0.01]. Children under 6 months revealed a 0.9 correlation between skin-epidural depth and body weight.

CONCLUSIONS

Ultrasonography is a useful aid to verify epidural placement of local anaesthetic agents and epidural catheters in children. Advantages include a reduction in bone contacts, faster epidural placement, direct visualization of neuraxial structures and the spread of local anaesthetic inside the epidural space. Ultrasound guidance requires additional training and good manual skills, and should only be used once experience in ultrasound-guided techniques of regional anaesthesia has been acquired.

The use of pre-operative intrathecal morphine for analgesia following coronary artery bypass surgery

With the emergence of rapid extubation protocols following cardiac surgery, providing adequate analgesia in the early postoperative period is important. This prospective randomised double-blind study investigated the benefits of pre-operative intrathecal administration of low dose morphine in patients undergoing coronary artery bypass graft surgery. Postoperative analgesia, pulmonary function, stress response and postoperative recovery profile were assessed. Thirty patients were allocated into two groups, receiving either 500 mug of morphine intrathecally prior to anaesthesia and intravenous patient-controlled analgesia with morphine postoperatively following tracheal extubation, or only postoperative intravenous patient-controlled analgesia. In the intrathecal group, the total consumption of intravenous morphine following surgery was significantly reduced by 40% and patients reported lower pain scores at rest, during the first 24 h following extubation. Peak expiratory flow rate was greater and postoperative catecholamine release was significantly lower. Patients in the control group had a higher incidence of reduced respiratory rate following extubation.

New approaches and old controversies to postoperative pain control following cardiac surgery

OBJECTIVE

To evaluate the effect of postoperative pain control in cardiac surgical patients on morbidity, mortality and other outcome measures.

BACKGROUND

New approaches in pain control have been introduced over the past decade. The impact of these interventions, either alone or in combination, on perioperative outcome was evaluated in cardiac surgical patients.

METHODS

We searched Medline for the period of 1980 to the present using the key terms analgesics, opioid, non-steroidal anti-inflammatory drugs, cardiac surgery, regional analgesia, spinal, epidural, fast-track cardiac anaesthesia, fast-track cardiac surgery, myocardial ischaemia, myocardial infarction, postoperative care, accelerated care programmes, postoperative complications, and we examined and discussed the articles that were identified to be included in this review.

RESULTS

Pain management in cardiac surgery is becoming more important with the establishment of minimally invasive direct coronary artery bypass surgery and fast-track management of conventional cardiac surgery patients. Advances have been made in this area and encompass specific techniques, such as central neuraxial blockade or selective nerve blocks, and drugs (opioids, sedative-hypnotics and non-steroidal anti-inflammatory drugs). Ideally, these therapies provide not only patient comfort but also mitigate untoward cardiovascular responses, pulmonary responses, and other inflammatory and secondary sympathetic responses. The introduction of these newer approaches to perioperative care has reduced morbidity, but not mortality, in cardiac surgical patients.

CONCLUSIONS

Understanding perioperative pathophysiology and implementation of care regimes to reduce the stress of cardiac surgery, will continue to accelerate rehabilitation associated with decreased hospitalization and increased satisfaction and safety after discharge. Reorganization of the perioperative team (anaesthesiologists, surgeons, nurses and physical therapists) will be essential to achieve successful fast-track cardiac surgical programmes. Developments and improvements of multimodal interventions within the context of 'fast-track' cardiac surgery programmes represents the major challenge for the medical professionals working to achieve a 'pain and risk free' perioperative course.

Imaging techniques for regional nerve blockade and vascular cannulation in children

PURPOSE OF REVIEW

This review identifies the most serious complications likely to be encountered in the current practice of paediatric anaesthesia.

RECENT FINDINGS

The findings of the ASA Closed Claims Project, published in 1993, showed a higher proportion of closed paediatric malpractice claims related to respiratory events than to cardiovascular events. The Pediatric Perioperative Cardiac Arrest Registry--an offshoot of the American Society of Anesthesiologists Closed Claims Project--reviewed cardiac arrest data collected between 1994 and 1997, revealing a shift in the aetiology of cardiac arrest during paediatric anaesthesia over the past 20 years. The study found that reported cardiac arrests were now more prevalent from cardiovascular causes than respiratory causes, unlike the findings in the previous Closed Claims Project. Follow-up data collected by both the Pediatric Perioperative Cardiac Arrest Registry and the American Society of Anesthesiologists Closed Claims Project confirm this trend.

SUMMARY

Outcomes for paediatric patients undergoing anaesthesia have improved over the years as a result of advances in monitoring and equipment, safer and more easily titratable anaesthetic agents, and possibly the practice of subspecialization. Preventable complications still, however, occur. An awareness of frequently encountered complications during paediatric anaesthesia may lead to the earlier detection and treatment of perioperative problems, leading to better outcomes.

Patient-controlledversus nurse-controlled analgesia after cardiac surgery — a meta-analysis

BACKGROUND

Patient-controlled analgesia (PCA) has been advocated as superior to conventional nurse-controlled analgesia (NCA) with less risk to patients. This systematic review and meta-analysis sought to determine whether PCA improves clinical and resource outcomes when compared with NCA.

METHODS

A comprehensive search was undertaken to identify all randomized controlled trials of PCA vs NCA. Medline, Cochrane Library, Embase, and conference abstract databases were searched from the date of their inception to August 2005. The primary postoperative outcome was defined as mean visual analogue scale (VAS) scores. Secondary postoperative outcomes included cumulative morphine equivalents, intensive care unit (ICU) and hospital length of stay, postoperative nausea and vomiting, sedation, respiratory depression, and all-cause mortality. Odds ratios or weighted mean differences (WMD) and their 95% confidence intervals (CI) were calculated for discrete and continuous outcomes, respectively.

RESULTS

Ten randomized trials involving 666 patients were included. Compared to NCA, PCA significantly reduced VAS at 48 hr (WMD -0.73, 95% CI -1.19, -0.27), but not at 24 hr (WMD -0.19, 95% CI -0.61, 0.24). Cumulative morphine equivalents consumed were significantly increased at 24 hr (WMD 6.84 mg, 95% CI 0.97, 12.72 mg), and at 48 hr (WMD 10.46 mg 95% CI 2.02, 18.9 mg) for PCA compared with NCA. Ventilation times, length of ICU stay, length of hospital stay, patient satisfaction scores, sedation scores, and incidence of postoperative nausea and vomiting, respiratory depression, severe pain, discontinuations, and death were not significantly different between groups, but these outcomes were generally under-reported.

CONCLUSIONS

In postcardiac surgical patients, PCA increases cumulative 24 and 48 hr morphine consumption, and improves 48-hr VAS compared with NCA.

Low-dose intrathecal morphine does not delay early extubation after cardiac surgery

PURPOSE

This study was designed to examine the efficacy of low-dose intrathecal morphine (ITM) on extubation times and pain control after cardiac surgery.

METHODS

43 patients undergoing elective cardiac surgery were enrolled in this prospective, randomized, double-blind placebo controlled trial. Patients were given a pre-induction dose of ITM (6 microg x kg(-1) per ideal body weight in 5 mL normal saline, group ITM) or 5 mL of intrathecal normal saline (group ITS). Anesthesia was induced with thiopental (3 mg x kg(-1)), sufentanil, midazolam and rocuronium. The total allowable doses of sufentanil and midazolam for the entire case were limited to 0.5 microg x kg(-1) and 0.045 mg x kg(-1) respectively. Anesthesia was maintained with isoflurane before and during cardiopulmonary bypass (CPB), and with propofol after CPB. In the postanesthesia care unit, patients received nurse-administered morphine followed by patient-controlled analgesia morphine. Serial visual analogue scale pain scores, morphine use, mini-mental state examinations and pulmonary function tests were measured for 48 hr. Patient satisfaction questionnaires were completed at the time of discharge.

RESULTS

Mean times to extubation from the application of dressings were short and did not differ between groups (ITM = 41.4 +/- 33.0 min, ITS = 39.2 +/- 37.1 min). During the first 24 hr postoperatively, the ITM group had improved pain control and a lower iv morphine requirement than the control group, both at rest and during deep breathing. Both forced expiratory volume in one second and forced vital capacity were improved in the ITM group. There were no differences in spinal-related side effects or in the overall complication rates. Patient satisfaction was high in both groups.

CONCLUSION

Low-dose ITM for cardiac surgery did not delay early extubation, but it improved postoperative analgesia and pulmonary function.

Delay in final publication following abstract presentation: American College of Veterinary Anesthesiologists annual meeting

RATIONALE FOR THE STUDY

A review of abstracts presented at nine annual meetings of the American College of Veterinary Anesthesiologists was undertaken to determine the average time to publication and the differences found between conference abstracts and final publications. Concerns about and advantages of using such abstracts in our teaching are considered.

METHODOLOGY

Conference proceedings during the years 1990 through 1999 were considered. Key word and author searches using two common search engines were carried out to find whether abstracts presented had been published. The original article or its abstract was reviewed for consistency with the conference abstract.

RESULTS

Of 283 abstracts examined, 73.5% were published in journals as full articles. The overall delay (+/-SD) in publication was 24.3 +/- 21.0 months. Common reasons for not publishing included too little time, more interest in carrying out the work than in writing it up, and other more demanding tasks. Authors indicated the intention of completing a submission on approximately 10% of the unpublished abstracts. The final articles reviewed showed major differences in key aspects from the abstract presented in 7% of the cases. In half of these cases, clinical action could have been affected by a change in emphasis of the conclusions.

CONCLUSIONS

Because of the delay in publication of research, peer review of standardized abstracts should be encouraged. This material can be used to introduce students to new drugs, techniques, and results that may not otherwise become available until after their graduation. However, caution must be exercised in using this information, both because significant differences were noted in final publications and because unpublished research may be poorly interpreted at the time of presentation. This study emphasizes the value of critical review and lifelong learning in our careers.

Intrathecal and Epidural Anesthesia and Analgesia for Cardiac Surgery

Adequate postoperative analgesia prevents unnecessary patient discomfort. It may also decrease morbidity, postoperative hospital length of stay and, thus, cost. Achieving optimal pain relief after cardiac surgery is often difficult. Many techniques are available, and all have specific advantages and disadvantages. Intrathecal and epidural techniques clearly produce reliable analgesia in patients undergoing cardiac surgery. Additional potential benefits include stress response attenuation and thoracic cardiac sympathectomy. The quality of analgesia obtained with thoracic epidural anesthetic techniques is sufficient to allow cardiac surgery to be performed in awake patients without general endotracheal anesthesia. However, applying regional anesthetic techniques to patients undergoing cardiac surgery is not without risk. Side effects of local anesthetics (hypotension) and opioids (pruritus, nausea/vomiting, urinary retention, and respiratory depression), when used in this manner, may complicate perioperative management. Increased risk of hematoma formation in this scenario has generated much of lively debate regarding the acceptable risk-benefit ratio of applying regional anesthetic techniques to patients undergoing cardiac surgery.

High thoracic epidural anesthesia and coronary artery disease in surgical and non-surgical patients

PURPOSE OF REVIEW

Even though high thoracic epidural anesthesia has been shown to be highly efficacious in the control of symptoms in refractory angina, its general use is still restricted. In patients who undergo coronary revascularization, however, the technique is becoming more and more popular. The present review outlines the use of high thoracic epidural anesthesia in patients with ischemic heart disease who underwent coronary revascularization in order to further reveal high thoracic epidural anesthesia's low complication rate and to analyze why physicians still refrain from using it more frequently.

RECENT FINDINGS

The incidence of severe hemodynamic complications after high thoracic epidural anesthesia is low in patients with coronary artery disease. The main advantage would be a myocardial sympathectomy leading to an improvement in the oxygen input-demand relationship. Likewise, a decrease in mortality due to respiratory complications could not be shown. In patients undergoing myocardial revascularization with full anticoagulation there is an increased risk of epidural hematoma formation. Its precise risk is difficult to evaluate. There is an overall low rate of epidural hematomas as a result of high thoracic epidural anesthesia. With the available data, the incidence has been estimated at between 1/1500 and 1/10,000.

SUMMARY

Epidural anesthesia does not decrease mortality or the incidence of myocardial infarction after coronary artery bypass grafting. It reduces the incidence of arrhythmias and respiratory complications and improves the quality of analgesia. High thoracic epidural anesthesia has been shown to be a safe and efficient technique for refractory angina that reduces the frequency of ischemic events and improves the clinical condition of patients.

Spinal anesthesia

PURPOSE OF REVIEW

The aim of this article is to review current practice of spinal anesthesia regarding technique and medication use; review recent applications of spinal anesthesia to subspecialty care in outpatient, cardiac, and obstetrical anesthesia; and update risk assessment associated with spinal anesthesia.

RECENT FINDINGS

Epidural volume extension enhances the spread of local anesthetics using a combined spinal-epidural technique. Chloroprocaine has become the agent of choice at some institutions. The growth in both the number and complexity of ambulatory surgery procedures has redefined the role of spinal anesthesia for outpatients. The 27-gauge Whitacre spinal needle is associated with a lower incidence of post-dural puncture headaches. Retrospective reviews can predict the incidence of rare complications such as neurologic injury and cardiac arrest.

SUMMARY

Innovations in technology, equipment, and needle design improved safety and decreased complication rates from spinal anesthesia. The increased popularity of ambulatory surgical procedures has resulted in more frequent use of spinal anesthesia. Intrathecal narcotic analgesia is used increasingly in fast-tracking cardiac surgical protocols. Modern anesthetic and analgesic techniques include resurgence of older agents (2-chloroprocaine) as well as new agents (levobupivacaine and ropivacaine) that are used in conjunction with adjuvant intrathecal medications (opioids, vasopressors, and alpha-2 adrenergic agonists). Surgical thromboprophylaxis and the increased use of anticoagulants in patients with cardiovascular disease have challenged anesthesiologists to update clinical guidelines to minimize the risk of hemorrhagic complications such as epidural hematoma. The risk/benefit ratio of spinal anesthesia should be individualized. The continued popularity of spinal anesthesia is due to the safety, effectiveness and efficiency of this technique.

The Effect of Thoracic Epidural Analgesia on the Occurrence of Late Postoperative Hypoxemia in Patients Undergoing Elective Coronary Bypass Surgery

STUDY OBJECTIVES

To evaluate the effect of perioperative thoracic epidural analgesia followed by postoperative epidural analgesia compared with conventional IV anesthesia on the occurrence of late postoperative hypoxemia in patients undergoing elective coronary bypass graft (CABG) surgery.

DESIGN

Randomized controlled trial.

SETTING

Cardiac surgery unit at a university hospital.

PATIENTS

A total of 50 patients undergoing elective CABG surgery.

INTERVENTION

Patients were randomly assigned to receive either conventional IV anesthesia (CON) or general anesthesia combined with thoracic epidural anesthesia followed by postoperative epidural analgesia (TEA) with bupivacaine. Postoperatively, the patients were monitored in the surgical ward with a pulse oximeter for a total of two postoperative nights (the second and third postoperative nights).

MEASUREMENTS AND RESULTS

The overall incidence of episodic hypoxemia was 56% (28 of 50 patients) on the second postoperative night and 89% (41 of 46 patients) on the third postoperative night. More than 30 episodes of hypoxemia developed on the second night in 22% of patients (11 of 50 patients), and on the third night in 30% of patients (14 of 46 patients). Despite oxygen therapy, 7% of patients (3 of 46 patients) experienced constant hypoxemia on the third night. In general, hypoxemia seemed to be slightly worse on the third postoperative night compared with the second postoperative night. Significantly more patients in the TEA group (25 of 25 patients) experienced episodic hypoxemia on the third postoperative night compared with the CON group (16 of 21 patients; p < 0.05). Otherwise, there were no significant differences between the two regimens.

CONCLUSIONS

Both episodic and constant hypoxemia were common in the late postoperative period in patients on the ward after CABG surgery with no clinically significant intergroup differences. Thus, perioperative epidural anesthesia/analgesia combined with postoperative epidural anesthesia/analgesia was not protective against hypoxemia, and therapy with opioids did not seem to be of importance for the occurrence of late postoperative hypoxemia on nights 2 and 3 after CABG surgery.

Influence of anaesthetic and analgesic techniques on outcome after surgery

Postoperative symptoms and complications can be prevented by a suitable choice of anaesthetic and analgesic technique for specific procedures. The aim of analgesic protocols is not only to reduce pain intensity but also to decrease the incidence of side-effects from analgesic agents and to improve patient comfort. Moreover, adequate pain control is a prerequisite for the use of rehabilitation programmes to accelerate recovery from surgery. Thus, combining opioid and/or non-opioid analgesics with regional analgesic techniques not only improves analgesic efficacy but also reduces opioid demand and side-effects such as nausea and vomiting, sedation, and prolongation of postoperative ileus. Although all attempts to demonstrate that regional anaesthesia and analgesia decrease postoperative mortality are unsuccessful, there is evidence supporting a reduction in pulmonary complications after major abdominal surgery, and an improvement in patient rehabilitation after orthopaedic surgery. When such techniques are used, cost-benefit analysis should be considered to determine suitable analgesic protocols for specific surgical procedures.

Update in thoracic epidural anaesthesia

Thoracic epidural analgesia (TEA) provides optimal perioperative anaesthesia and analgesia after thoracic and major abdominal surgery and decreases postoperative morbidity and mortality, mainly by blocking sympathetic nerve fibres. Surgery leads to a stress response characterized by sympathetic arousal, altered balance of catabolic and anabolic hormones, hypermetabolism, negative protein economy, and altered carbohydrate metabolism and immune function. A threefold increase of the plasma level of norepinephrine (noradrenaline) was detected up to 24 hours after surgery. These elevated catecholamine plasma levels are a risk, especially to patients with coronary artery disease, because unlike healthy coronary arteries, the stress response causes a vasoconstriction in arteriosclerotic coronary arteries. TEA results in a vasodilation in stenotic coronary arteries. In patients with instable angina pectoris, TEA reduced the number as well as the duration of episodes of cardiac ischaemia. Furthermore, TEA improves myocardial structure and function after coronary artery bypass grafting. Plasma levels of troponin T and I, as well as of atrial natriuretic peptides, were reduced and echocardiographic parameters of the ventricular wall motion were improved by TEA. Patients showed fewer arrhythmic episodes and postoperative myocardial infarction, and could be extubated earlier. The positive effects of TEA after coronary artery bypass grafting are not limited to a short postoperative period, the 2-year mortality rate also seems to be reduced. Optimized pain control and early mobilization decrease the riskof pulmonary complications, resulting in a shortened stay in intensive care units. In combination with early enteral nutrition, TEA leads to an earlier return of gastrointestinal function. Patients treated with thoracic epidural anaesthesia and analgesia have a better health-related quality of life.

Effects of high thoracic epidural analgesia on myocardial blood flow in patients with ischemic heart disease

BACKGROUND

In patients with ischemic heart disease, high thoracic epidural analgesia (TEA) has been proposed to improve abnormalities of coronary function by inhibiting cardiac sympathetic tone. We evaluated the effect of TEA on myocardial blood flow in patients with ischemic heart disease.

METHODS AND RESULTS

Twenty male patients with multivessel ischemic heart disease were studied. An epidural catheter was inserted between the second and third thoracic vertebral interspace (Th2 to Th3). Analgesia was induced by epidural injection of bupivacaine 0.5%, and a sensory block from the sixth cervical (C6 to C7) to Th10 (Th8 to Th11) vertebral interspace was achieved. Myocardial blood flow was measured with dynamic 13N-ammonia PET with and without TEA at rest, during pharmacological vasodilation with dipyridamole, and during sympathetic stimulation with the cold pressor test. Myocardial blood flow during dipyridamole increased similarly, regardless of TEA, in all regions except in myocardium subtended by collateral arteries in which blood flow increased more with than without TEA (P<0.05). Without TEA, myocardial blood flow during the cold pressor test remained unchanged compared with myocardial blood flow at rest. In contrast, with TEA, myocardial blood flow increased in all vascular territories. Coronary vascular resistance increased during the cold pressor test without TEA, whereas with TEA, coronary resistance decreased in myocardium subtended by nonstenotic and stenotic coronary vessels and remained unchanged in myocardium subtended by occluded vessels.

CONCLUSIONS

In patients with multivessel ischemic heart disease, TEA partly normalizes the myocardial blood flow response to sympathetic stimulation.

Epidural Analgesia for Postoperative Pain

Epidural analgesia provides superior analgesia compared with other postoperative analgesic techniques. Additionally, perioperative epidural analgesia confers physiologic benefits, which may potentially decrease perioperative complications and improve postoperative outcome. However, there are many variables (eg, choice of analgesics, catheter-incision congruency, and duration of analgesia) that may influence the efficacy of epidural analgesia. In addition, the use of epidural analgesia should be evaluated on an individual basis because there are risks associated with this technique.

Consequences of Inadequate Postoperative Pain Relief and Chronic Persistent Postoperative Pain

Inadequately controlled pain has undesirable physiologic and psychologic consequences such as increased postoperative morbidity, delayed recovery, a delayed return to normal daily living, and reduced patient satisfaction. Importantly, the lack of adequate postoperative pain treatment may lead to persistent pain after surgery, which is often overlooked. Overall, inadequate pain management increases the use of health care resources and health care costs. This article reviews the physiologic and psychologic consequences of inadequately treated pain, with an emphasis on chronic persistent postoperative pain.

Non-analgetic effects of thoracic epidural anaesthesia

PURPOSE OF REVIEW

This review presents a brief overview of the non-analgetic effects of thoracic epidural anaesthesia. It covers the cardiac, pulmonary and gastrointestinal effects of thoracic epidural anaesthesia. The results of newer studies are of particular importance regarding mortality and major morbidity after thoracic epidural anaesthesia.

RECENT FINDINGS

The clinical effects of thoracic epidural anaesthesia are mainly attributed to a transient thoracic sympathetic block affecting different organs. Furthermore, local anaesthetic itself reabsorbed from the epidural space may contribute to the non-analgetic effects of thoracic epidural anaesthesia. Experimental studies have suggested that thoracic epidural anaesthesia may attenuate the perioperative stress response after major surgery. The possible beneficial mechanisms of action include an improvement of left ventricular function by direct anti-ischaemic effects, a reduction in cardiovascular complications, an advance on gastrointestinal function, and a reduction in pulmonary complications, as well as a positive impact on the coagulation system and the postoperative inflammatory response. However, it is questionable whether these effects of thoracic epidural anaesthesia may lead to an improved perioperative outcome after major surgery. Recent studies have suggested that, despite the superior quality of pain relief and better quality of life, thoracic epidural anaesthesia does not reduce mortality and major morbidity, especially after major abdominal and cardiac surgery.

SUMMARY

Despite this controversy, the numerous positive effects and advantages of thoracic epidural anaesthesia are the reasons for its increasing popularity. However, the advantages of thoracic epidural anaesthesia must be incorporated into a multimodal treatment management aimed at improving outcomes after surgery.