Intrathecal morphine for coronary artery bypass graft procedure and early extubation revisited

Non-pulmonary complications of intrathecal morphine administration: a systematic review and meta-analysis with meta-regression

BACKGROUND

Intrathecal morphine provides effective analgesia for a range of operations. However, widespread implementation into clinical practice is hampered by concerns for potential side-effects. We undertook a systematic review, meta-analysis, and meta-regression with the primary objective of determining whether a threshold dose for non-pulmonary complications could be defined and whether an association could be established between dose and complication rates when intrathecal morphine is administered for perioperative or obstetric analgesia.

METHODS

We systematically searched the literature for randomised controlled trials comparing intrathecal morphine vs control in patients undergoing any type of surgery under general or spinal anaesthesia, or women in labour. Primary outcomes were rates of postoperative nausea and vomiting, pruritus, and urinary retention within the first 24 postoperative hours, analysed according to doses (1-100 μg; 101-200 μg; 201-500 μg; >500 μg), type of surgery, and anaesthetic strategy. Trials were excluded if doses were not specified.

RESULTS

Our analysis included 168 trials with 9917 patients. The rates of postoperative nausea and vomiting, pruritus, and urinary retention were significantly increased in the intrathecal morphine group, with an odds ratio (95% confidence interval) of 1.52 (1.29-1.79), P<0.0001; 6.11 (5.25-7.10), P<0.0001; and 1.73 (1.17-2.56), P=0.005, respectively. Meta-regression could not establish an association between dose and rates of non-pulmonary complications. There was no subgroup difference according to surgery for any outcome. The quality of evidence was low (Grading of Recommendations Assessment, Development, and Evaluation [GRADE] system).

CONCLUSIONS

Intrathecal morphine significantly increased postoperative nausea and vomiting, pruritus, and urinary retention after surgery or labour in a dose-independent manner.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023387838).

Comparison of intrathecal low-dose bupivacaine and morphine with intravenous patient control analgesia for postoperative analgesia for video-assisted thoracoscopic surgery

BACKGROUND

Thoracoscopic surgical techniques continue to advance, yet the intensity of postoperative pain remains significant, impeding swift patient recovery. This study aimed to evaluate the differences in postoperative pain and recuperation between patients receiving intrathecal morphine paired with low-dose bupivacaine and those administered general anesthesia exclusively.

METHODS

This randomized controlled trial enrolled 100 patients, who were allocated into three groups: Group M (5 μg/kg morphine intrathecal injection), Group B (5 μg/kg morphine combined with bupivacaine 3 mg intrathecal injection) and Group C (intrathecal sham injection). The primary outcome was the assessment of pain relief using the Numeric Rating Scale (NRS). Additionally, intraoperative remifentanil consumption was quantified at the end of the surgery, and postoperative opioid use was determined by the number of patient-controlled analgesia (PCIA) compressions at 48 h post-surgery. Both the efficacy of the treatments and any complications were meticulously recorded.

RESULTS

Postoperative NRS scores for both rest and exercise at 6, 12, 24, and 48 h were significantly lower in groups M and B than in group C (P<0.05). The intraoperative remifentanil dosage was significantly greater in groups M and C than in group B (P<0.05), while there was no significant difference between groups M and C (P>0.05). There was no significant difference in intraoperative propofol dosage across all three groups (P>0.05). Postoperative dosages of both sufentanil and Nonsteroidal anti-inflammatory drugs (NSAIDs) were significantly less in groups M and B compared to group C (P<0.05). The time of first analgesic request was later in both groups M and B than in group C (P<0.05). Specific and total scores were elevated at 2 days postoperative when compared to scores at 1 day for all groups (P<0.05). Furthermore, at 1 day and 2 days postoperatively, both specific scores and total scores were higher in groups M and B compared to group C (P<0.05).

CONCLUSION

Intrathecal administration of morphine combined with bupivacaine has been shown to effectively ameliorate acute pain in patients undergoing thoracoscopic surgery.

TRIAL REGISTRATION

The trial was registered on ClinicalTrials.gov: ChiCTR2200058544, registered 10/04/2022.

Intrathecal Morphine for Analgesia in Minimally Invasive Cardiac Surgery: A Randomized, Placebo-controlled, Double-blinded Clinical Trial

BACKGROUND

Intrathecal morphine decreases postoperative pain in standard cardiac surgery. Its safety and effectiveness have not been adequately evaluated in minimally invasive cardiac surgery. The authors hypothesized that intrathecal morphine would decrease postoperative morphine consumption after minimally invasive cardiac surgery.

METHODS

In this randomized, placebo-controlled, double-blinded clinical trial, patients undergoing robotic totally endoscopic coronary artery bypass received either intrathecal morphine (5 mcg/kg) or intrathecal saline before surgery. The primary outcome was postoperative morphine equivalent consumption in the first 24 h after surgery; secondary outcomes included pain scores, side effects, and patient satisfaction. Pain was assessed via visual analog scale at 1, 2, 6, 12, 24, and 48 h after intensive care unit arrival. Opioid-related side effects (nausea/vomiting, pruritus, urinary retention, respiratory depression) were assessed daily. Patient satisfaction was evaluated with the Revised American Pain Society Outcome Questionnaire.

RESULTS

Seventy-nine patients were randomized to receive intrathecal morphine (n = 37) or intrathecal placebo (n = 42), with 70 analyzed (morphine 33, placebo 37). Intrathecal morphine patients required significantly less median (25th to 75th percentile) morphine equivalents compared to placebo during first postoperative 24 h (28 [16 to 46] mg vs. 59 [41 to 79] mg; difference, -28 [95% CI, -40 to -18]; P < 0.001) and second postoperative 24 h (0 [0 to 2] mg vs. 5 [0 to 6] mg; difference, -3.3 [95% CI, -5 to 0]; P < 0.001), exhibited significantly lower visual analog scale pain scores at rest and cough at all postoperative timepoints (overall treatment effect, -4.1 [95% CI, -4.9 to -3.3] and -4.7 [95% CI, -5.5 to -3.9], respectively; P < 0.001), and percent time in severe pain (10 [0 to 40] vs. 40 [20 to 70]; P = 0.003) during the postoperative period. Mild nausea was more common in the intrathecal morphine group (36% vs. 8%; P = 0.004).

CONCLUSIONS

When given before induction of anesthesia for totally endoscopic coronary artery bypass, intrathecal morphine decreases use of postoperative opioids and produces significant postoperative analgesia for 48 h.

EDITOR’S PERSPECTIVE

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.

Enhanced recovery after surgery with intrathecal opioid in a patient of Gilbert's syndrome undergoing mitral valve replacement

Gilbert's syndrome, an inherited autosomal dominant disorder, is the most common cause of congenital unconjugated hyperbilirubinaemia. We report the anaesthetic management of a 46-year-old female with Gilbert's syndrome operated for mitral valve replacement (MVR), with a special focus on the role of intrathecal opioids.

Initial Perioperative Care of the Cardiac Surgical Patient

Recently, changes in the management of cardiac patients have allowed earlier discharge from the cardiac recovery area and reduced hospital length of stay. These changes have been drien by a need to reduce the cost of cardiac surgery and imrove efficiency. This change has been both financially sucessful and safe for patients. To allow for this success, a joint effort is required between the departments of cardiac surgery and anesthesiology involving the preoperative, intraoperative and postoperative treatment of these patients. Through recogition of suitable candidates, modifications in anesthetic techique, and appropriate postoperative management, the goal of extubation within 6 hours of admission to the cardiac recovery area can be achieved. Changes in intraoperative and early postoperative management of cardiac surgical patients are discussed. Specific recovery models are reviewed with disussion of the parallel and integrated models. Methods of preicting prolonged extubation times and intensive care unit length of stay are also discussed. Initial management of the cardiac patient in the cardiac recovery area is presented with a more in-depth review of specific complications: stroke, atril fibrillation, blood loss, left ventricular dysfunction, and pulonary dysfunction.

Pulmonary Complications After Cardiac Surgery

Over the past two decades there has been a steady evolution in the practice of adult cardiac surgery with the introduction of “off-pump” surgery. However, respiratory complications remain a leading cause of postcardiac surgical morbidity and can prolong hospital stays and increase costs. The high incidence of pulmonary complications is in part due to the disruption of normal ventilatory function that is inherent to surgery in the thoracic region. Furthermore, patients undergoing such surgery often have underlying illnesses such as intrinsic lung disease (e.g., chronic obstructive pulmonary disease) and pulmonary dysfunction secondary to cardiac disease (e.g., congestive heart failure) that increase their susceptibility to postoperative respiratory problems. Given that many patients undergoing cardiac surgery are thus susceptiple to pulmonary complications, it is remarkable that more patients do not suffer from them during and after cardiac surgery. This is to a large degree because of advances in anesthetic, surgical and critical care that, for example, have reduced the physiological insults of surgery (e.g., better myocardial preservation techniques) and streamlined care in the immediate postoperative period (e.g., early extubation). Moreover, the development of minimally invasive surgery and nonbypass techniques are further evidence of the attempts at reducing the homeostatic disruptions of cardiac surgery. This review examines the available information on the incidences, consequences, and treatments of postcardiac surgery respiratory complications.

Is there any benefit in associating neuraxial anesthesia to general anesthesia for coronary artery bypass graft surgery?

BACKGROUND AND OBJECTIVES

The use of neuraxial anesthesia in cardiac surgery is recent, but the hemodynamic effects of local anesthetics and anticoagulation can result in risk to patients.

OBJECTIVE

To review the benefits of neuraxial anesthesia in cardiac surgery for CABG through a systematic review of systematic reviews.

CONTENT

The search was performed in Pubmed (January 1966 to December 2012), Embase (1974 to December 2012), The Cochrane Library (volume 10, 2012) and Lilacs (1982 to December 2012) databases, in search of articles of systematic reviews. The following variables: mortality, myocardial infarction, stroke, in-hospital length of stay, arrhythmias and epidural hematoma were analyzed.

CONCLUSIONS

The use of neuraxial anesthesia in cardiac surgery remains controversial. The greatest benefit found by this review was the possibility of reducing postoperative arrhythmias, but this result was contradictory among the identified findings. The results of findings regarding mortality, myocardial infarction, stroke and in-hospital length of stay did not show greater efficacy of neuraxial anesthesia.

Benefit and risk of intrathecal morphine without local anaesthetic in patients undergoing major surgery: meta-analysis of randomized trials

Intrathecal morphine without local anaesthetic is often added to a general anaesthetic to prevent pain after major surgery. Quantification of benefit and harm and assessment of dose-response are needed. We performed a meta-analysis of randomized trials testing intrathecal morphine alone (without local anaesthetic) in adults undergoing major surgery under general anaesthesia. Twenty-seven studies (15 cardiac-thoracic, nine abdominal, and three spine surgery) were included; 645 patients received intrathecal morphine (dose-range, 100-4000 microg). Pain intensity at rest was decreased by 2 cm on the 10 cm visual analogue scale up to 4 h after operation and by about 1 cm at 12 and 24 h. Pain intensity on movement was decreased by 2 cm at 12 and 24 h. Opioid requirement was decreased intraoperatively, and up to 48 h after operation. Morphine-sparing at 24 h was significantly greater after abdominal surgery {weighted mean difference, -24.2 mg [95% confidence interval (CI) -29.5 to -19.0]}, compared with cardiac-thoracic surgery [-9.7 mg (95% CI -17.6 to -1.80)]. The incidence of respiratory depression was increased with intrathecal morphine [odds ratio (OR) 7.86 (95% CI 1.54-40.3)], as was the incidence of pruritus [OR 3.85 (95% CI 2.40-6.15)]. There was no evidence of linear dose-responsiveness for any of the beneficial or harmful outcomes. In conclusion, intrathecal morphine decreases pain intensity at rest and on movement up to 24 h after major surgery. Morphine-sparing is more pronounced after abdominal than after cardiac-thoracic surgery. Respiratory depression remains a major safety concern.

Intrathecal morphine plus general anesthesia in cardiac surgery: effects on pulmonary function, postoperative analgesia, and plasma morphine concentration

OBJECTIVES

To evaluate the effects of intrathecal morphine on pulmonary function, analgesia, and morphine plasma concentrations after cardiac surgery.

INTRODUCTION

Lung dysfunction increases morbidity and mortality after cardiac surgery. Regional analgesia may improve pulmonary outcomes by reducing pain, but the occurrence of this benefit remains controversial.

METHODS

Forty-two patients were randomized for general anesthesia (control group n=22) or 400 microg of intrathecal morphine followed by general anesthesia (morphine group n=20). Postoperative analgesia was accomplished with an intravenous, patient-controlled morphine pump. Blood gas measurements, forced vital capacity (FVC), forced expiratory volume (FEV), and FVC/FEV ratio were obtained preoperatively, as well as on the first and second postoperative days. Pain at rest, profound inspiration, amount of coughing, morphine solicitation, consumption, and plasma morphine concentration were evaluated for 36 hours postoperatively. Statistical analyses were performed using the repeated measures ANOVA or Mann-Whiney tests (*p<0.05).

RESULTS

Both groups experienced reduced FVC postoperatively (3.24 L to 1.38 L in control group; 2.72 L to 1.18 L in morphine group), with no significant decreases observed between groups. The two groups also exhibited similar results for FEV1 (p=0.085), FEV1/FVC (p=0.68) and PaO2/FiO2 ratio (p=0.08). The morphine group reported less pain intensity (evaluated using a visual numeric scale), especially when coughing (18 hours postoperatively: control group= 4.73 and morphine group= 1.80, p=0.001). Cumulative morphine consumption was reduced after 18 hours in the morphine group (control group= 20.14 and morphine group= 14.20 mg, p=0.037). The plasma morphine concentration was also reduced in the morphine group 24 hours after surgery (control group= 15.87 ng.mL-1 and morphine group= 4.08 ng.mL-1, p=0.029).

CONCLUSIONS

Intrathecal morphine administration did not significantly alter pulmonary function; however, it improved patient analgesia and reduced morphine consumption and morphine plasma concentration.

NSAID-analgesia, pain control and morbidity in cardiothoracic surgery

OBJECTIVE

While narcotics remain the backbone of perioperative analgesia, the adjunctive role of other analgesics, including non-steroidal anti-inflammatory drugs (NSAIDs), is being recognized increasingly. This meta-analysis sought to determine whether adjunctive NSAIDs improve postoperative analgesia and reduce cumulative narcotic requirements.

METHODS

A comprehensive search was undertaken to identify all randomized trials, in cardiothoracic patients, of NSAIDs plus narcotics vs narcotics without NSAIDs. Medline, Cochrane Library, EMBASE, and abstract databases were searched up to September 2005. The primary outcome was visual analogue scale (VAS) pain score. Secondary outcomes included 24-hr cumulative morphine-equivalents, rescue medications required, mortality, myocardial infarction, atrial fibrillation, stroke, renal failure, hospital readmissions, and in-hospital costs.

RESULTS

Twenty randomized trials involving 1,065 patients were included. A significant reduction in 24-hr VAS pain score was found in patients receiving NSAIDs [weighted mean difference (WMD) -0.91 points, 95% confidence interval (CI) -1.48 to -0.34 points]. In addition, patients required significantly less morphine-equivalents in the first 24 hr (WMD -7.67 mg, 95% CI -8.97 to -6.38 mg). No significant difference was found with respect to mortality [odds ratio (OR) 0.19, 95% CI 0.01 to 4.22], myocardial infarction (OR 0.71, 95% CI 0.09 to 5.71), renal dysfunction (OR 0.95, 95% CI 0.37 to 2.46), or gastrointestinal bleeding (OR 0.96, 95% CI 0.13 to 7.09).

CONCLUSION

In patients less than 70 yr of age undergoing cardiothoracic surgery, the adjunctive use of NSAIDs with narcotic analgesia reduces 24-hr VAS pain score and narcotic requirements.

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.

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.

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.

Combination of Intrathecal Morphine and Remifentanil Infusion for Fast-Track Anesthesia in Off-Pump Coronary Artery Bypass Surgery

OBJECTIVE

The purpose of this study was to assess the combination of intrathecal morphine and remifentanil infusion with isoflurane in off-pump coronary artery surgery, with a focus on postoperative analgesia and fast-tracking.

DESIGN

Prospective, randomized, controlled, blinded clinical study.

SETTING

University hospital.

PARTICIPANTS

Forty-six patients who underwent elective off-pump coronary artery bypass grafting.

INTERVENTIONS

Patients were randomly assigned to receive remifentanil infusion alone (control group, n = 23) or remifentanil infusion plus 10 microg/kg of intrathecal morphine (ITM group, n = 23). Induction and maintenance anesthesia were the same in both groups. Maintenance therapy was remifentanil infusion (0.25-1 microg/kg/min) and 0.5% to 1.5% isoflurane, with adjustments according to hemodynamics. After extubation, intravenous patient-controlled analgesia with morphine (1-mg bolus and 5-minute lockout) was administered, and Wilson sedation scores, visual analog pain scores (scale, 0-100 mm) at rest and during coughing, and cumulative morphine consumption were assessed at 1, 2, 4, 8, 12, 24, and 48 hours. Examiners were unaware of patients' group identities. Anesthetic recovery parameters and opioid-related, spinal anesthesia-related, and cardiac complications were recorded.

MEASUREMENTS AND MAIN RESULTS

There were no differences between the groups' intraoperative hemodynamic or anesthetic recovery findings. Pain scores and morphine consumption were significantly lower in the ITM group at all time points after extubation (p = 0.0001-0.05). Group frequencies of opioid-related and cardiac complications were similar. No patient had central neuroaxial hematoma or post-spinal tap headache.

CONCLUSION

In the setting of isoflurane anesthesia for off-pump coronary artery bypass grafting, ITM combined with remifentanil infusion provides better postoperative analgesia than does remifentanil infusion alone, and does not improve or negatively affect fast-tracking.

The effects of intrathecal morphine on patients undergoing minimally invasive direct coronary artery bypass surgery

OBJECTIVE

To evaluate the effects of intrathecal morphine (ITM) on the perioperative use of opiates and the fast-track pathway in patients undergoing minimally invasive direct coronary artery bypass grafting (MIDCAB).

DESIGN

Retrospective cohort study.

SETTINGS

University teaching hospital.

PARTICIPANTS

Twenty-two elective consecutive patients who underwent MIDCAB surgery.

INTERVENTIONS

Eleven patients received an intrathecal injection of morphine, 7 microg/kg (ITM group, n=11), and the control group (n=11) received standard anesthesia care.

MEASUREMENTS AND MAIN RESULTS

The intraoperative dose of fentanyl was 0.55+/-0.2 mg in the ITM group and 1.1+/-0.2 mg in the control group (p<0.0001). Four patients in the ITM group and none in the control group were extubated in the operating room. Extubation time was 3.2+/-4.7 hours in the ITM group and 6.3+/-3.4 hours in the control group (p=0.016). Morphine requirements in 24 hours after surgery were 2.0+/-3.5 mg in the ITM and 16.1+/-4.8 mg in the control group (p<0.0001). There were no differences in ischemic time, intraoperative fluid requirements, postoperative blood loss, and duration of surgical procedure. Hospital length of stay was shorter in the ITM group compared with the control group (3.9+/-1.7 days v 4.9+/-1.4 days, respectively, p=0.047).

CONCLUSIONS

ITM has to be considered in MIDCAB surgery as an effective component of the perioperative analgesia. The safety and effects of ITM in the patients recovery after MIDCAB surgery should be evaluated in further prospective studies.

Low dose intrathecal morphine facilitates early extubation after cardiac surgery: results of a retrospective continuous quality improvement audit

PURPOSE

To document one centre's experience with a multimodal analgesic approach, with or without low dose intrathecal morphine (ITM), in facilitating "fast-track" recovery in patients undergoing cardiac surgery.

METHODS

Records of 131 consecutive patients who underwent first time elective cardiac surgery during a four-month period in 2000 were reviewed. Patients were divided into two groups: those receiving and those not receiving preoperative low dose ITM (< 5 microgxkg(-1)) as part of a multimodal analgesic technique. Demographic and surgical characteristics, postoperative morphine use, time to extubation and requirement for antiemetics were recorded.

RESULTS

Overall, 75% of patients were extubated within two hours, and 93% within six hours. Fifty-five patients received, and 76 did not receive, ITM (mean +/- SD 259 +/- 53 microg) along with a multimodal analgesic technique (parasternal infiltration, acetaminophen and indomethacin, and postoperative i.v. morphine). Anesthetic technique involved modest dose opioids, volatile agent and propofol infusion. The groups were similar with respect to preoperative, intraoperative and anesthetic characteristics. Mean extubation time for fast-track patients receiving vs not receiving ITM was 75 +/- 65 vs 117 +/- 85 min (P = 0.003). Intravenous morphine use for the first 12 hr after surgery was also reduced in the ITM group (4.6 +/- 4.1 vs 10.0 +/- 14.8 mg, P = 0.009). There was no difference in rescue antiemetic or antipruritic requirements, failed fast-tracking, or serious adverse events.

CONCLUSIONS

Multimodal postoperative analgesia allowed for uneventful early extubation and low opioid requirements. Low dose ITM further facilitated early extubation, and reduced postoperative analgesic requirements.

Fast-track coronary artery bypass grafting surgery under general anesthesia with remifentanil and spinal analgesia with morphine and clonidine

OBJECTIVE

Effective postoperative analgesia is a critical part of fast-track cardiac surgery. This study compared the postoperative analgesic effect of fast-track anesthesia with remifentanil and spinal morphine and clonidine with that of sufentanil anesthesia followed by patient-controlled administration of intravenous morphine.

DESIGN

Prospective, blinded, randomized study.

SETTING

Single private institution.

PARTICIPANTS

Forty patients selected for coronary artery bypass graft surgery allocated randomly into 2 groups.

INTERVENTIONS

General anesthesia was performed with etomidate, isoflurane, cisatracurium, and either remifentanil (0.10-0.25 microg/kg/min) or sufentanil (up to 3.5 microg/kg). In the remifentanil group, patients received spinal morphine (4 microg/kg) and clonidine (1 microg/kg) before induction. Postoperatively, patients in both groups were connected to an intravenous patient-controlled analgesia (PCA) morphine pump that delivered a 1-g bolus with a 7-minute lockout interval.

MEASUREMENTS AND MAIN RESULTS

Patients were evaluated for pain on a visual analog scale (VAS), at rest and on deep breathing, and for intravenous PCA morphine consumption during 24 hours. The intravenous PCA morphine 24-hour cumulative dose was lower in the fast-track than in the control group (15.8+/-12.6 v 32.7+/-22.3 mg, p<0.05). Before extubation, VAS scores were higher in the fast-track group, but after they were lower both at rest and during deep breathing. Extubation delay was shorter in the fast-track group (156.5+/-46.1 v 272+/-116.4 minutes, p<0.05).

CONCLUSION

The combination of anesthesia with remifentanil and spinal analgesia with morphine and clonidine produces effective analgesia after coronary artery surgery and a rapid extubation time.

Postoperative Pulmonary Dysfunction in Adults After Cardiac Surgery With Cardiopulmonary Bypass: Clinical Significance and Implications for Practice

Postoperative pulmonary complications are the most frequent and significant contributor to morbidity, mortality, and costs associated with hospitalization. Interestingly, despite the prevalence of these complications in cardiac surgical patients, recognition, diagnosis, and management of this problem vary widely. In addition, little information is available on the continuum between routine postoperative pulmonary dysfunction and postoperative pulmonary complications. The course of events from pulmonary dysfunction associated with surgery to discharge from the hospital in cardiac patients is largely unexplored. In the absence of evidence-based practice guidelines for the care of cardiac surgical patients with postoperative pulmonary dysfunction, an understanding of the pathophysiological basis of the development of postoperative pulmonary complications is fundamental to enable clinicians to assess the value of current management interventions. Previous research on postoperative pulmonary dysfunction in adults undergoing cardiac surgery is reviewed, with an emphasis on the pathogenesis of this problem, implications for clinical nursing practice, and possibilities for future research.

Intrathecal morphine for off-pump coronary artery bypass grafting

OBJECTIVE

To determine if preinduction intrathecal morphine is associated with successful intraoperative extubation in patients undergoing off-pump coronary artery bypass grafting.

DESIGN

A retrospective noncontrolled chart review of all patients undergoing off-pump coronary artery bypass grafting.

SETTING

Single university hospital.

PARTICIPANTS

One hundred twelve patients.

INTERVENTIONS

One hundred twelve of 150 patients received preinduction intrathecal morphine as part of routine anesthetic care for off-pump coronary artery bypass grafting. Patients received a mean of 1.0 mg of intrathecal morphine (range 0.3-1.6 mg); average weight-corrected dose was 13.2 microg/kg (range 5-24 microg/kg).

MEASUREMENTS AND MAIN RESULTS

This study included intraoperative extubation rate, delayed respiratory depression, and other complications potentially attributable to intrathecal morphine. An intraoperative extubation rate of 77% was found. Five patients received naloxone postoperatively, 4 of them for delayed respiratory depression.

CONCLUSIONS

It is concluded that intrathecal morphine is associated with a high intraoperative extubation rate in patients undergoing off-pump coronary artery bypass grafting. The authors' practice included 24-hour respiratory monitoring to detect delayed respiratory depression.

Definitions of "respiratory depression" with intrathecal morphine postoperative analgesia: a review of the literature

PURPOSE

To review the postoperative intrathecal morphine (ITM) analgesia literature for their definitions of "respiratory depression" (RD).

SOURCE

Medline (1966 - June Week 5 2001) and reference lists were searched for original studies involving bolus-dose ITM for postoperative analgesia, which used "respiratory depression" or similar terms.

PRINCIPLE FINDINGS

The search identified 209 studies. These were included if ITM use was appropriate (bolus dose, postoperative analgesia) and the term "respiratory depression" was used, which left 96 studies remaining. Forty-four (46%) did not define "RD" despite using this term. A further 24 (25%) defined RD with respiratory rate (RR) alone. Only 28 (29%) defined RD with more than RR alone. There was no statistically significant association between the presence of a definition for RD with study design, study size or publication period. Also, no significant association existed between rigorousness of RD definitions and the above factors.

CONCLUSION

The term "respiratory depression" has no clear definition from a review of the literature on ITM use for postoperative analgesia. While defining RD with bradypnea is superior to having no definition, this is still inadequate. In future research, the consistent use of terms with specific meanings will facilitate understanding the true incidence of ITM's respiratory effects. If "respiratory depression" is used, then an explicit definition of its meaning should be provided. Future research must also address what is clinically significant respiratory impairment from intrathecal opioids, and how to optimally monitor for this. Further delineating their risks vs benefits will allow for more optimal dosing.

Target-controlled infusion of propofol and remifentanil in cardiac anaesthesia: influence of age on predicted effect-site concentrations

BACKGROUND

Propofol-anaesthesia administrated via target-controlled infusion (TCI) has been proposed for cardiac surgery. Age-related changes in pharmacology explain why propofol dose requirement is reduced in elderly patients. However, the Marsh pharmacokinetic model incorporated in the Diprifusor propofol device does not take age into account as a covariable. In the absence of depth of anaesthesia monitoring, this limitation could cause adverse cardiovascular effects resulting from propofol overdose in older patients. We assessed the influence of age on effect-site propofol concentrations predicted by the Diprifusor and titrated to the bispectral index score (BIS) during cardiac anaesthesia.

METHODS

Forty-five patients received propofol by Diprifusor and remifentanil by software including Minto model. Propofol and remifentanil effect-site concentrations were adapted to BIS (40-60) and haemodynamic profile, respectively. The influence of age on effect-site concentrations was assessed by dividing patients into two groups: young (<65 yr) and elderly (> or =65 yr).

RESULTS

For a similar depth of anaesthesia, effect-site propofol concentrations were significantly lower in elderly patients at the different stages of cardiac surgery. The mean dose of propofol required to perform tracheal intubation was significantly lower in elderly patients. However, the overall doses of propofol were comparable in both groups. Neither effect-site remifentanil concentrations nor overall doses of remifentanil were significantly different between the two groups.

CONCLUSIONS

In cardiac anaesthesia, target concentrations of propofol must be reduced in elderly patients. Although this probably contributes to improving intraoperative haemodynamic stability, the absence of decrease in overall dose requirement of propofol suggests that this adjustment is relatively moderate.

Intrathecal morphine and clonidine for coronary artery bypass grafting

BACKGROUND

After cardiac surgery adequate postoperative analgesia is necessary. We assessed analgesia using intrathecal morphine and clonidine.

METHODS

In a double-blind randomized study, 45 patients having coronary artery bypass graft surgery were allocated randomly to receive i.v. patient-controlled analgesia (PCA) morphine (bolus, 1 mg; lock-out interval, 7 min) (control group), either alone or combined with intrathecal morphine 4 microg kg(-1) or with both intrathecal morphine 4 microg kg(-1) and clonidine 1 microg kg(-1). Intrathecal injections were performed before the induction of general anaesthesia. Pain was measured after surgery using a visual analogue scale (VAS). We recorded i.v. PCA morphine consumption during the 24 h after operation.

RESULTS

Morphine dosage [median (25th-75th percentiles)] was less in the first 24 h in the patients who were given intrathecal morphine + clonidine [7 (0-37) mg] than in other patients [40.5 (15-61.5) mg in the intrathecal morphine group and 37 (30.5-51) mg in the i.v. morphine group]. VAS scores were lower after intrathecal morphine + clonidine compared with the control group. Time to extubation was less after intrathecal morphine + clonidine compared with the i.v. morphine group [225 (195-330) vs 330 (300-360) min, P<0.05].

CONCLUSION

Intrathecal morphine and clonidine provide effective analgesia after coronary artery bypass graft surgery and allow earlier extubation.

A combination of intrathecal morphine and remifentanil anesthesia for fast-track cardiac anesthesia and surgery

OBJECTIVE

To determine if the combined remifentanil and intrathecal morphine (RITM) anesthetic technique facilitates early extubation in patients undergoing coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective, randomized, controlled clinical trial.

SETTING

Referral center for cardiothoracic surgery at a university hospital.

PARTICIPANTS

Patients (n = 24) undergoing first-time elective CABG surgery.

INTERVENTIONS

Two groups represented RITM (n = 12) and fentanyl-based (controls, n = 12) anesthesia. Premedication was standardized to temazepam, 0.4 mg/kg, and anesthesia was induced with etomidate, 0.3 mg/kg, in both groups. The RITM group received remifentanil, 1 microg/kg bolus followed by 0.25 to 1 microg/kg/min infusion, and intrathecal morphine, 2 mg. The control group received fentanyl, 12 microg/kg in 3 divided doses. Anesthesia was maintained with isoflurane and pancuronium in both groups. After completion of surgery, the remifentanil infusion was stopped. Complete reversal of muscle relaxation was ensured with a nerve stimulator, and a propofol infusion, 0.5 to 3 mg/kg/h, was started in both groups. All patients were transferred to the intensive care unit (ICU) to receive standardized postoperative care. Intensivists and ICU nurses were blinded to the group assignment. Propofol infusion was stopped, and the tracheal extubation was accomplished when extubation criteria were fulfilled.

MEASUREMENTS AND MAIN RESULTS

Both groups were similar with respect to demographic data and surgical characteristics. Extubation times were 156 +/- 82 minutes and 258 +/- 91 minutes in the RITM and control groups (p = 0.012). Patients in the RITM group exhibited lower visual analog scale pain scores during the first 2 hours after extubation (p < 0.04). Morphine requirements during the 24 hours after extubation were 2.5 +/- 3 mg in the RITM group and 16 +/- 11 mg in the control group (p = 0.0018). Sedation scores were lower in the RITM group during the first 3 hours after extubation (p < 0.03). Pulmonary function tests as assessed by spirometry were better in the RITM group at 6 and 12 hours after extubation (p < 0.04). There were no significant differences in PaO(2) and PaCO(2) after extubation between the 2 groups. None of the patients had episodes of apnea during the immediate 24-hour postextubation period. Two patients from the RITM group required reintubation on the second and sixth postoperative days. There were no differences in ICU and hospital length of stay between the 2 groups.

CONCLUSION

Implementation of the RITM technique provided earlier tracheal extubation, decreased level of sedation, excellent analgesia, and improved spirometry in the early postoperative period. The impact of RITM on ICU and hospital length of stay and potential cost benefits require further evaluation.

Intrathecal morphine after cardiac surgery

OBJECTIVE

To assess whether intrathecal (IT) analgesia facilitates early extubation and provides superior pain control after cardiac surgery compared with patient-controlled analgesia (PCA) or nurse-administered SC injections.

METHODS

Sixty-two patients undergoing elective cardiac surgery participated in this prospective, randomized, partly-blinded study. Perioperative care was standardized, and patients were assigned to receive IT morphine (ITM group) followed by PCA, IT placebo (ITP group) followed by PCA, or SC injections of morphine every 4 hours as needed (SC group). Rating scales and questionnaires were used to assess clinical outcomes.

RESULTS

ITM did not favor earlier extubation, and there was even a tendency for longer extubation times in the ITM group compared with the ITP and SC groups. Pain scores, adverse effects, postoperative recovery, and patient satisfaction were also comparable in the 3 groups.

CONCLUSIONS

Considering that the administration of IT morphine is more costly and can be riskier than conventional analgesic regimens, we conclude that its use is not indicated in patients undergoing cardiac surgery if early extubation is planned.

Postoperative intensive care in cardiac surgery

Postoperative intensive care in cardiac surgery is a growing area, fuelled by the increase in the number of cardiac surgical procedures performed. An increase in the number of patients has resulted in increased resource utilization. Much of the recent research in this field is concerned with the early extubation of cardiac surgical patients, reducing the length of stay in the intensive care unit and predicting which patients will have delayed extubation and a prolonged length of stay. A number of recent studies have been published advocating 'off pump' cardiac surgery as a way of reducing the physiological insult of cardiopulmonary bypass and thereby improving the postoperative course. There is still insufficient evidence that this approach reduces morbidity and intensive care unit length of stay in multi-vessel off-pump coronary artery bypass surgery. The traditional design of post-cardiac surgical intensive care units and high dependency units has also recently been challenged. More flexible integrated units improve cost control and are more suited to modern cardiac surgery.