Effects of thoracic epidural analgesia on coronary hemodynamics and myocardial metabolism in coronary artery bypass surgery

Current Status of Neuraxial and Paravertebral Blocks for Adult Cardiac Surgery

Cardiac surgeries are known to produce moderate to severe pain. Pain management has traditionally been based on intravenous opioids. Poorly controlled pain can result in increased incidence of respiratory complications such as atelectasis and pneumonia leading to prolonged intubation and intensive care unit length of stay and subsequent prolonged hospital stay. Adequate perioperative analgesia improves hemodynamics and immunologic responses, which would result in better outcomes after cardiac surgery. Opioid sparing "Enhanced Recovery After Surgery" protocols are increasingly being incorporated into cardiac surgeries. This will reduce opioid requirements and opioid-related side effects and facilitate fast-tracking of patients. Regional analgesia can be provided by neuraxial blocks, fascial plane blocks, peripheral nerve blocks, or simply by the infiltration of the wound with local anesthetics for cardiac surgery. Neuraxial analgesia is provided through epidural, spinal, and paravertebral routes. Though they are being replaced by peripheral fascial plane blocks, epidural and spinal analgesia are still being used in some centers. In this article, neuraxial forms of analgesia are focused. We sought to review epidural analgesia and its impact in suppressing hemodynamic stress response, reducing pulmonary complications, and development of chronic pain. The relationship between intraoperative heparinization and potential neuraxial hematoma is discussed. Other neuraxial options such as spinal and paravertebral analgesia and their usefulness, benefits, and limitations are also reviewed.

Epidural analgesia for adults undergoing cardiac surgery with or without cardiopulmonary bypass

BACKGROUND

General anaesthesia combined with epidural analgesia may have a beneficial effect on clinical outcomes. However, use of epidural analgesia for cardiac surgery is controversial due to a theoretical increased risk of epidural haematoma associated with systemic heparinization. This review was published in 2013, and it was updated in 2019.

OBJECTIVES

To determine the impact of perioperative epidural analgesia in adults undergoing cardiac surgery, with or without cardiopulmonary bypass, on perioperative mortality and cardiac, pulmonary, or neurological morbidity.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase in November 2018, and two trial registers up to February 2019, together with references and relevant conference abstracts.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) including adults undergoing any type of cardiac surgery under general anaesthesia and comparing epidural analgesia versus another modality of postoperative pain treatment. The primary outcome was mortality.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures as expected by Cochrane.

MAIN RESULTS

We included 69 trials with 4860 participants: 2404 given epidural analgesia and 2456 receiving comparators (systemic analgesia, peripheral nerve block, intrapleural analgesia, or wound infiltration). The mean (or median) age of participants varied between 43.5 years and 74.6 years. Surgeries performed were coronary artery bypass grafting or valvular procedures and surgeries for congenital heart disease. We judged that no trials were at low risk of bias for all domains, and that all trials were at unclear/high risk of bias for blinding of participants and personnel taking care of study participants.Epidural analgesia versus systemic analgesiaTrials show there may be no difference in mortality at 0 to 30 days (risk difference (RD) 0.00, 95% confidence interval (CI) -0.01 to 0.01; 38 trials with 3418 participants; low-quality evidence), and there may be a reduction in myocardial infarction at 0 to 30 days (RD -0.01, 95% CI -0.02 to 0.00; 26 trials with 2713 participants; low-quality evidence). Epidural analgesia may reduce the risk of 0 to 30 days respiratory depression (RD -0.03, 95% CI -0.05 to -0.01; 21 trials with 1736 participants; low-quality evidence). There is probably little or no difference in risk of pneumonia at 0 to 30 days (RD -0.03, 95% CI -0.07 to 0.01; 10 trials with 1107 participants; moderate-quality evidence), and epidural analgesia probably reduces the risk of atrial fibrillation or atrial flutter at 0 to 2 weeks (RD -0.06, 95% CI -0.10 to -0.01; 18 trials with 2431 participants; moderate-quality evidence). There may be no difference in cerebrovascular accidents at 0 to 30 days (RD -0.00, 95% CI -0.01 to 0.01; 18 trials with 2232 participants; very low-quality evidence), and none of the included trials reported any epidural haematoma events at 0 to 30 days (53 trials with 3982 participants; low-quality evidence). Epidural analgesia probably reduces the duration of tracheal intubation by the equivalent of 2.4 hours (standardized mean difference (SMD) -0.78, 95% CI -1.01 to -0.55; 40 trials with 3353 participants; moderate-quality evidence). Epidural analgesia reduces pain at rest and on movement up to 72 hours after surgery. At six to eight hours, researchers noted a reduction in pain, equivalent to a reduction of 1 point on a 0 to 10 pain scale (SMD -1.35, 95% CI -1.98 to -0.72; 10 trials with 502 participants; moderate-quality evidence). Epidural analgesia may increase risk of hypotension (RD 0.21, 95% CI 0.09 to 0.33; 17 trials with 870 participants; low-quality evidence) but may make little or no difference in the need for infusion of inotropics or vasopressors (RD 0.00, 95% CI -0.06 to 0.07; 23 trials with 1821 participants; low-quality evidence).Epidural analgesia versus other comparatorsFewer studies compared epidural analgesia versus peripheral nerve blocks (four studies), intrapleural analgesia (one study), and wound infiltration (one study). Investigators provided no data for pulmonary complications, atrial fibrillation or flutter, or for any of the comparisons. When reported, other outcomes for these comparisons (mortality, myocardial infarction, neurological complications, duration of tracheal intubation, pain, and haemodynamic support) were uncertain due to the small numbers of trials and participants.

AUTHORS' CONCLUSIONS

Compared with systemic analgesia, epidural analgesia may reduce the risk of myocardial infarction, respiratory depression, and atrial fibrillation/atrial flutter, as well as the duration of tracheal intubation and pain, in adults undergoing cardiac surgery. There may be little or no difference in mortality, pneumonia, and epidural haematoma, and effects on cerebrovascular accident are uncertain. Evidence is insufficient to show the effects of epidural analgesia compared with peripheral nerve blocks, intrapleural analgesia, or wound infiltration.

Pain Management After Vascular Surgery

Patients presenting for vascular surgery usually have concomitant disease processes that may increase the likelihood of adverse outcomes after major surgery. Because of the advanced nature of the underlying medical condition, it is important to optimize postopera tive pain control to adequately control postoperative discomfort, stress response, hypercoagulability, myocar dial ischemia, and graft failure. This article discusses methods of pain control after vascular surgery and their effects on physiology and outcome.

Epidural analgesia for cardiac surgery

BACKGROUND

A combination of general anaesthesia (GA) with thoracic epidural analgesia (TEA) may have a beneficial effect on clinical outcomes by reducing the risk of perioperative complications after cardiac surgery.

OBJECTIVES

The objective of this review was to determine the impact of perioperative epidural analgesia in cardiac surgery on perioperative mortality and cardiac, pulmonary or neurological morbidity. We performed a meta-analysis to compare the risk of adverse events and mortality in patients undergoing cardiac surgery under general anaesthesia with and without epidural analgesia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2012, Issue 12) in The Cochrane Library; MEDLINE (PubMed) (1966 to November 2012); EMBASE (1989 to November 2012); CINHAL (1982 to November 2012) and the Science Citation Index (1988 to November 2012).

SELECTION CRITERIA

We included randomized controlled trials comparing outcomes in adult patients undergoing cardiac surgery with either GA alone or GA in combination with TEA.

DATA COLLECTION AND ANALYSIS

All publications found during the search were manually and independently reviewed by the two authors. We identified 5035 titles, of which 4990 studies did not satisfy the selection criteria or were duplicate publications, that were retrieved from the five different databases. We performed a full review on 45 studies, of which 31 publications met all inclusion criteria. These 31 publications reported on a total of 3047 patients, 1578 patients with GA and 1469 patients with GA plus TEA.

MAIN RESULTS

Through our search (November 2012) we have identified 5035 titles, of which 31 publications met our inclusion criteria and reported on a total of 3047 patients. Compared with GA alone, the pooled risk ratio (RR) for patients receiving GA with TEA showed an odds ratio (OR) of 0.84 (95% CI 0.33 to 2.13, 31 studies) for mortality; 0.76 (95% CI 0.49 to 1.19, 17 studies) for myocardial infarction; and 0.50 (95% CI 0.21 to 1.18, 10 studies) for stroke. The relative risks (RR) for respiratory complications and supraventricular arrhythmias were 0.68 (95% CI 0.54 to 0.86, 14 studies) and 0.65 (95% CI 0.50 to 0.86, 15 studies) respectively.

AUTHORS' CONCLUSIONS

This meta-analysis of studies, identified to 2010, showed that the use of TEA in patients undergoing coronary artery bypass graft surgery may reduce the risk of postoperative supraventricular arrhythmias and respiratory complications. There were no effects of TEA with GA on the risk of mortality, myocardial infarction or neurological complications compared with GA alone.

Epidural analgesia improves outcome in cardiac surgery: a meta-analysis of randomized controlled trials

OBJECTIVE

The authors conducted a review of randomized studies to determine whether there were any advantages for clinically relevant outcomes by adding epidural analgesia in patients undergoing cardiac surgery under general anesthesia.

DESIGN

Meta-analysis.

SETTING

Hospitals.

PARTICIPANTS

A total of 2366 patients from 33 randomized trials.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

DATA SOURCES AND STUDY SELECTION

PubMed, BioMedCentral, CENTRAL, EMBASE, Cochrane Central Register of Controlled Trials, and conference proceedings were searched (updated January 2008) for randomized trials that compared general anesthesia with an anesthetic plan including general anesthesia and epidural analgesia in cardiac surgery. Two independent reviewers appraised study quality, with divergences resolved by consensus. Overall analysis showed that epidural analgesia reduced the risk of the composite endpoint mortality and myocardial infarction (30/1125 [2.7%] in the epidural group v 64/1241 [5.2%] in the control arm, odds ratio [OR] = 0.61 [0.40-0.95], p = 0.03 number needed to treat [NNT] = 40), the risk of acute renal failure (35/590 [5.9%] in the epidural group v 54/618 [8.7%] in the control arm, OR = 0.56 [0.34-0.93], p = 0.02, NNT = 36), and the time of mechanical ventilation (weighted mean differences = -2.48 hours [-2.64, -2.32], p < 0.001).

CONCLUSIONS

This analysis suggested that epidural analgesia on top of general anesthesia reduced the incidence of perioperative acute renal failure, the time on mechanical ventilation, and the composite endpoint of mortality and myocardial infarction in patients undergoing cardiac surgery.

[Coronary artery bypass grafting in conscious patients: a procedure with a perspective?]

Patients undergoing coronary artery bypass grafting increasingly show severe co-morbidities, which can negatively affect the outcome. Recent developments in cardiac surgery have therefore focused on minimizing the invasiveness of the procedure by revascularization on the beating heart without cardiopulmonary bypass, and by reducing surgical trauma using smaller surgical incisions. Progress in minimally invasive cardiac surgery has led to minimally invasive anesthesia, i.e. using high thoracic epidural anesthesia as the sole technique in the conscious patient (awake coronary artery bypass grafting, ACAB). Published data on ACAB procedures in smaller cohorts have demonstrated that the procedure is safe. Significant complications occurred in 7.1% of patients. A particular cause of concern during ACAB surgery is the development of spinal epidural hematoma the risk of which has been estimated to be as high as 1:1,000. A thorough risk-benefit analysis has therefore to be made. Currently, ACAB surgery remains limited to few specialized centers and highly selected patients.

A novel approach for pain management in cardiac surgery via median sternotomy: bilateral single-shot paravertebral blocks

Regional analgesia has entered cardiac anesthesia in the form of spinal or epidural analgesia. However, the risk of spinal or epidural hematoma is a constant worry. Alternative regional techniques might be applicable in cardiac surgery. The purpose of this study is to present a novel technique of bilateral single-shot paravertebral blocks (BSS-PVB) for cardiac surgery via median sternotomy and compare its efficacy versus high thoracic epidural analgesia (TEA). Fifty-two patients were compared in this prospective cohort audit. In 26 patients, cardiac surgery was performed using low-dose fentanyl/BSS-PVB (bilateral blocks of 3 mL bupivacaine 0.5% each, T1-7) and general anesthesia; in another 26 patients, TEA (bupivacaine 0.125% at 10 mL/hour) and general anesthesia were used. Patients were assigned to cohorts according to their preoperative data and types of surgery. All patient data are shown as mean +/- SD; pain scores were compared between groups using the t test immediately, 6 hours, and 24 hours after surgery (P < .05). In the BSS-PVB-group (19 men, 7 women), mean age was 65 +/- 11 years, weight 74 +/- 16 kg, ejection fraction 59% +/- 12%, and duration of surgery 130 +/- 27 minutes; in the TEA-group (17 men, 9 women), mean age was 63 +/- 10 years, weight 75 +/- 16 kg, ejection fraction 58% +/- 12%, and duration of surgery 113 +/- 27 minutes. These data and preoperative comorbidity variables were not significantly different between the two groups. In each group, 18 patients underwent off-pump coronary artery bypass grafting, 3 on-pump and 5 mitral valve replacements. All patients were successfully immediately extubated. Postoperative pain scores were at any point significantly lower with TEA, immediately at 2.4 +/- 2.2 versus 3.7 +/- 2.6, at 6 hours at 1.1 +/- 1.5 versus 2.4 +/- 1.8, and at 24 hours at 1.0 +/- 1.4 versus 2.3 +/- 1.6 (0 = no pain, 10 = maximum pain). There was no complications related to epidural catheter placement or BSS-PVB. Using both techniques, immediate extubation after cardiac surgery is feasible; TEA provides better pain relief after cardiac surgery than BSS-PVB.

The risk of vertebral canal complications in 2837 cardiac surgery patients with thoracic epidurals

BACKGROUND

Recent communications in the medical press have suggested that the rate of vertebral canal complications following epidural catheter placement is increasing in frequency, in particular the incidence of epidural abscess (Hearn M. Epidural abscess complicating insertion of epidural catheters. Br J Anaesth 2003; 90 (5): 706-7; Govasi C, Bland D, Poddar R, Horst C. Epidural abscess complicating insertion of epidural catheters. Br J Anaesth 2004; 92 (2): 294-5). We wished to investigate this in our population of cardiac surgical patients.

METHODS

We performed a retrospective review of the data from all patients who had undergone coronary artery bypass grafting or valve replacement surgery in our hospital over the past 8 years. This involved a review of computer databases, logbooks, radiology records, admission records, intensive care transfers, pain team ward round data and follow-up outpatient data referrals.

RESULTS

In total, 2837 patient admissions were examined and reviewed by the authors. No episodes of vertebral canal haematoma or abscess were observed.

CONCLUSIONS

Retrospective analysis of our working practice indicates that thoracic epidural anaesthesia and analgesia are safe in patients receiving cardiac surgery. We found no epidural haematoma or abscess in 2837 patients.

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.

Comparison of three different epidural solutions in off-pump cardiac surgery: pilot study

BACKGROUND

Immediate extubation using thoracic epidural analgesia (TEA) has become more popular after off-pump coronary artery bypass grafting (OPCAB). In this randomized prospective double-blind study, we present the first comparison of preoperative and postoperative haemodynamics during different regimens of TEA for immediate extubation after cardiac surgery.

METHODS

Sixty patients undergoing OPCAB were enrolled in this study. TEA was installed >1 h before application of heparin at levels T2-T4. Analgesia was provided by bupivacaine 0.25%, 8 ml, 15 min before surgery and extubation, and at 10 ml h(-1) during surgery and up to 72 h afterwards using one of the following regimens: bupivacaine 0.125% alone, bupivacaine 0.125% with fentanyl 3 microg ml(-1) or bupivacaine 0.125% with clonidine 0.6 microg ml(-1). Patients were block-randomized for one of the three treatments. Pain scores and infusion rates of TEA were assessed up to 48 h after surgery. Respiratory function was assessed by Pa(o2) and Pa(o2) immediately after surgery, and haemodynamic stability was recorded in the form of heart rate and diastolic and systolic blood pressure.

RESULTS

Patient characteristics, respiratory function and haemodynamic stability did not vary between the three groups. Pain control was very good and was not significantly different between the groups using similar infusion rates after surgery. Paraesthesia in dermatomes T1 or C8 occurred equally in all three groups. There was no neurological complication related to TEA in this study.

CONCLUSIONS

We conclude that immediate extubation after OPCAB using TEA is feasible with different TEA regimens. Respiratory function, haemodynamic stability and pain control are not different between TEA with bupivacaine alone, bupivacaine with fentanyl or bupivacaine with clonidine.

A prospective randomized study of the potential benefits of thoracic epidural anesthesia and analgesia in patients undergoing coronary artery bypass grafting

We performed an open, prospective, randomized, controlled study of the incidence of major organ complications in 420 patients undergoing routine coronary artery bypass graft surgery with or without thoracic epidural anesthesia and analgesia (TEA). All patients received a standardized general anesthetic. Group TEA received TEA for 96 h. Group GA (general anesthesia) received narcotic analgesia for 72 h. Both groups received supplementary oral analgesia. Twelve patients were excluded-eight in Group TEA and four in Group GA-because of incomplete data collection. New supraventricular arrhythmias occurred in 21 of 206 patients (10.2%) in Group TEA compared with 45 of 202 patients (22.3%) in Group GA (P = 0.0012). Pulmonary function (maximal inspiratory lung volume) was better in Group TEA in a subset of 93 patients (P < 0.0001). Extubation was achieved earlier (P < 0.0001) and with significantly fewer lower respiratory tract infections in Group TEA (TEA = 31 of 206, GA = 59 of 202; P = 0.0007). There were significantly fewer patients with acute confusion (GA = 11 of 202, TEA = 3 of 206; P = 0.031) and acute renal failure (GA = 14 of 202, TEA = 4 of 206; P = 0.016) in the TEA group. The incidence of stroke was insignificantly less in the TEA group (GA = 6 of 202, TEA = 2 of 206; P = 0.17). There were no neurologic complications associated with the use of TEA. We conclude that continuous TEA significantly improves the quality of recovery after coronary artery bypass graft surgery compared with conventional narcotic analgesia.

Epidural sufentanil during paediatric cardiac surgery: effects on metabolic response and postoperative outcome

The metabolic and neuroendocrine effects of caudal epidural analgesia were studied during paediatric cardiac surgery. Combined epidural and general anaesthesia (EPI group; n=12) was compared with deep opioid anaesthesia (DOA group; n=12). During anaesthesia and surgery, haemodynamic stability was similar in the two groups. There was no significant difference between groups concerning the metabolic response to surgery but circulating catecholamines were significantly lower in the EPI group during and after surgery. Perioperative release of IL-6 was higher in the EPI group possibly reflecting a longer aortic clamp time. Incidence of postoperative life-threatening dysrhythmias was very low in the two groups. No significant reduction of postoperative mechanical ventilation, intensive care unit or hospital stays was reported with epidural analgesia. The incidence of postoperative infections was higher than expected in the two groups because of the poor properative clinical status of most of the children included in the study.

Regional anaesthesia in patients at coronary risk for noncardiac and cardiac surgery

This review presents a brief overview about the role of regional anaesthesia in patients at risk for myocardial ischemia and/or infarction after cardiac and noncardiac surgical procedures. It includes pathophysiological insights in the problems of plaque rupture and the possible interactions by the use of regional anaesthesia. Special emphasis is put on the subject of thoracic epidural anaesthesia with newer studies showing improvement in relief of angina and improvement of global systolic and diastolic function in patients with coronary artery disease.

Minimally invasive direct coronary artery bypass grafting: changes in anesthetic management and surgical procedure

OBJECTIVE

The authors hypothesized that changes in surgical procedures for minimally invasive direct coronary artery bypass grafting (MIDCAB) have led to changes in anesthetic management with a resultant decrease in the complexity of care.

DESIGN

Retrospective observational study.

SETTING

University teaching hospital.

PARTICIPANTS

Review of the records of 60 patients who underwent MIDCAB surgery.

MEASUREMENTS AND MAIN RESULTS

Data included preoperative demographics, perioperative anesthetic management, and postoperative cardiac and noncardiac issues and complications. Two groups were formed: in group I, a coronary stabilizer (CS) was not used, and in group II, it was. With the exception of a greater incidence of those with no preoperative comorbidities in group II (CS), there were no differences between the two groups with respect to demographics or preoperative variables. A surgical design called H-graft was used in a greater number of group II (CS) patients, whereas a direct anastomosis was performed in the majority of group I patients. Use of pharmacologically induced bradycardia/asystole has not been performed after the introduction of the CS. The use of central venous catheters (instead of pulmonary artery catheters) and single-lumen (v double-lumen) endotracheal tubes was greater in group II (CS) patients. Despite changes in intraoperative management, there was no significant change in the incidence of postoperative complications, intensive care unit stay, and hospital stay between groups I and II. New-onset atrial fibrillation was the most common postoperative complication (13 of 56 patients; 23%). Three of 24 patients (12.5%) who received intraoperative magnesium experienced atrial fibrillation compared with 10 of 32 patients (31%) who did not receive magnesium.

CONCLUSIONS

The complexity of anesthetic technique has decreased since the onset of MIDCAB surgery. The decrease in complexity may be related to changes in surgical design and technology.