Cardiovascular response to large doses of intravenous morphine in man

Pain management and opioid stewardship in adult cardiac surgery: Joint consensus report of the PeriOperative Quality Initiative and the Enhanced Recovery After Surgery Cardiac Society

BACKGROUND

Opioid-based anesthesia and analgesia is a traditional component of perioperative care for the cardiac surgery patient. Growing enthusiasm for Enhanced Recovery Programs (ERPs) coupled with evidence of potential harm associated with high-dose opioids suggests that we reconsider the role of opioids in cardiac surgery.

METHODS

An interdisciplinary North American panel of experts, using a structured appraisal of the literature and a modified Delphi method, derived consensus recommendations for optimal pain management and opioid stewardship for cardiac surgery patients. Individual recommendations are graded based on the strength and level of evidence.

RESULTS

The panel addressed 4 main topics: the harms associated with historical opioid use, the benefits of more targeted opioid administration, the use of nonopioid medications and techniques, and patient and provider education. A key principle that emerged is that opioid stewardship should apply to all cardiac surgery patients, entailing judicious and targeted use of opioids to achieve optimal analgesia with the fewest potential side effects. The process resulted in the promulgation of 6 recommendations regarding pain management and opioid stewardship in cardiac surgery, focused on avoiding the use of high-dose opioids, as well as encouraging more widespread application of foundational aspects of ERPs, such as the use of multimodal nonopioid medications and regional anesthesia techniques, formal patient and provider education, and structured system-level opioid prescription practices.

CONCLUSIONS

Based on the available literature and expert consensus, there is an opportunity to optimize anesthesia and analgesia for cardiac surgery patients. Although additional research is needed to establish specific strategies, core principles of pain management and opioid stewardship apply to the cardiac surgery population.

The impact of multimodal analgesia in coronary artery bypass graft surgery-a population-based analysis

OBJECTIVE

Multimodal pain management aims to concurrently target several pain pathways for improved treatment efficacy and recovery. We investigated associations between multimodal analgesia use and postoperative complications, length of hospital stay (LOS), and opioid consumption among patients undergoing coronary artery bypass graft surgery.

METHODS

This retrospective cohort study included 349,940 adult patients undergoing elective coronary artery bypass graft surgery (January 2006 to December 2019), from the national Premier Healthcare claims dataset. The study intervention was multimodal analgesia, defined as opioid use with the addition of nonopioid analgesic modalities. These included, nonsteroidal anti-inflammatory drugs, cyclooxygenase-2 inhibitors, paracetamol/acetaminophen, neuraxial anesthesia, steroids, gabapentin/pregabalin, and ketamine. Analgesic management was stratified into 4 categories: opioids only and multimodal analgesia with the addition of 1, 2 or ≥3 nonopioid analgesic modalities. Mixed-effects regression models measured associations between multimodal analgesia and postoperative complications, LOS, and opioid consumption measured in milligram oral morphine equivalents.

RESULTS

Multimodal analgesia was associated with a beneficial dose response pattern. With increasing nonopioid analgesic modalities added to opioid analgesia, a stepwise decrease in complication risk was consistently observed, eg, with the addition of 1, 2, or ≥3 nonopioid modalities the odds for any complication decreased by 8% (odds ratio [OR], 0.92; confidence interval [CI], 0.90-0.94), 17% (OR, 0.83; CI, 0.81-0.86), and 22% (OR, 0.78; CI 0.69-0.79), respectively. This stepwise pattern was consistent in respiratory, cardiac, and renal complications individually. Similarly, LOS decreased stepwise with added analgesic modalities.

CONCLUSIONS

These nationally representative data indicate that enhanced pain management by multiple pain pathways is associated with significant reductions in postoperative complications and shortened patient recovery.

Parasternal intercostal plane block catheters for cardiac surgery: a retrospective, propensity weighted, cohort study

Aim: Anesthesia for cardiac surgery has evolved toward fast-track recovery strategies incorporating non opioid analgesics and regional anesthesia. Materials & methods: This retrospective cohort study compared opioid consumption, pain scores and length of stay in patients who underwent cardiac surgery via median sternotomy and did or did not receive preoperative parasternal intercostal plane block catheters with postoperative ropivacaine infusions. Results: Postoperative opioid consumption and postoperative pain scores did not differ. Blocks were associated with decreased intraoperative opioids and reduced length of stay in the intensive care unit and hospital. Conclusion: Parasternal intercostal plane block catheters were not associated with decreased postoperative opioid consumption or pain scores, but were associated with reduced intraoperative opioids and length of stay.

Perioperative opioids: a narrative review contextualising new avenues to improve prescribing

Opioids have dominated the management of perioperative pain in recent decades with higher doses than ever before used in some circumstances. Through the expanding use of opioids, growing research has highlighted their associated side-effects and the intertwined phenomena of acute withdrawal syndrome, opioid tolerance, and opioid-induced hyperalgesia. With multiple clinical guidelines now endorsing multimodal analgesia, a diverse array of opioid-sparing agents emerges and has been studied to variable degrees, including techniques of opioid-free anaesthesia. It remains unclear to what extent such methods should be adopted, yet current evidence does suggest dependence on opioids as the primary perioperative analgesic might not meet the principles of 'rational prescribing' as described by Maxwell. In this narrative review we describe how, using current evidence, a patient-centred rational-prescribing approach can be applied to opioids in the perioperative period. To contextualise this approach, we discuss the historical adoption of opioids in anaesthesia, our growing understanding of associated side-effects and emerging strategies of opioid-sparing and opioid-free anaesthesia. We discuss avenues and challenges for improving opioid prescribing to limit persistent postoperative opioid use and how these may be incorporated into a rational-prescribing approach.

Defining the role of thoracic spinal anaesthesia in the 21st century: a narrative review

Since the performance of the first thoracic spinal anaesthetic in early 1908 many anaesthetists have gained interest in this unorthodox neuraxial anaesthetic technique. The main rationale justifying its use is to prevent complications related to general anaesthesia in high-risk patient populations. There is, however, significant debate regarding this practice around the world. The main concerns are fear of iatrogenic injury to the spinal cord, cephalad spread of local anaesthetic causing a complete spinal block, and haemodynamic instability owing to blockade of cardioaccelerator sympathetic fibres. The purpose of this narrative review is to appraise the literature critically regarding thoracic spinal anaesthesia, to synthesise the available information, and to provide a summary of evidence justifying its use in modern anaesthesia.

Regional analgesia for cardiac surgery

PURPOSE OF REVIEW

Regional anesthesia is gaining attention as a valuable component of multimodal, opioid-sparing analgesia in cardiac surgery, where improving the patient's quality of recovery while minimizing the harms of opioid administration are key points of emphasis in perioperative care. This review serves as an outline of recent advancements in a variety of applications of regional analgesia for cardiac surgery.

RECENT FINDINGS

Growing interest in regional analgesia, particularly the use of newer "chest wall blocks", has led to accumulating evidence for the efficacy of multiple regional techniques in cardiac surgery. These include a variety of technical approaches, with results consistently demonstrating optimized pain control and reduced opioid requirements. Regional and pain management experts have worked to derive consensus around nerve block nomenclature, which will be foundational to establish best practice, design and report future research consistently, improve medical education, and generally advance our knowledge in this vital area of perioperative patient care.

SUMMARY

The field of regional analgesia for cardiac surgery has matured over the last several years. A variety of regional techniques have been described and shown to be efficacious as part of the multimodal, opioid-sparing approach to pain management in the cardiac surgical setting.

Controversies in enhanced recovery after cardiac surgery

Advances in cardiac surgical operative techniques and myocardial protection have dramatically improved outcomes in the past two decades. An unfortunate and unintended consequence is that 80% of the preventable morbidity and mortality following cardiac surgery now originates outside of the operating room. Our hope is that a renewed emphasis on evidence-based best practice and standardized perioperative care will reduce overall morbidity and mortality and improve patient-centric care. The Perioperative Quality Initiative (POQI) and Enhanced Recovery After Surgery–Cardiac Society (ERAS® Cardiac) have identified significant evidence gaps in perioperative medicine related to cardiac surgery, defined as areas in which there is significant controversy about how best to manage patients. These five areas of focus include patient blood management, goal-directed therapy, acute kidney injury, opioid analgesic reduction, and delirium.

Regional Anesthesia in Cardiac Surgery: A Review of the Literature

With our population getting older and sicker, we are witnessing a steady increase in the volume of cardiothoracic procedures performed. As the role of anesthesiologists continues to shift towards being perioperative physicians, it is crucial to tailor the anesthetic to manage the surgical pain in both intraoperative and postoperative periods. In cardiac surgery, poorly controlled surgical pain can lead to opioid-induced hyperalgesia as well as chronic pain syndrome. As current practice encourages early extubation and decreased length of stay, clinicians have increasingly steered away from heavy intraop narcotic therapy over the past two decades. To blunt the sympathetic response and postoperative pain control, some have been using various fascial plane nerve blocks to reduce opioid use during surgery. These blocks are considered very safe to perform and do not lead to hemodynamic changes seen in neuraxial blockades. In this review article, we provide a brief overview of each of the commonly used blocks and summarize and discuss the latest clinical data for each of the common blocks and their efficacy in the setting of cardiothoracic surgery.

Cardiothoracic Anesthesia and Critical Care in the United Kingdom (UK) Part 1: Some Insights Into the History and Development

This review is intended to highlight some of the historic events that contributed to the development of thoracic and cardiac anesthesia and surgery in Great Britain and Northern Ireland (UK). The aim of this first of two parts is to concentrate on the development of techniques, facilities, and pharmacology that allowed progress and advancement in patient management that were developed primarily in the UK. However, progress usually requires input from a wide variety of sources of knowledge, and cardiothoracic practice is no exception. Reference is, thus, made to sources outside of the UK that guided, influenced, or inspired changes in practice, such as the techniques of operating on the heart and great vessels in war casualties, developed by Dr. Dwight Harken, or the demonstration of the Blalock-Thomas-Taussig shunt by Alfred Blalock. In addition to advances in medical equipment, such as computed tomography, the UK contributed greatly to pharmacologic interventions that were unique at the time in such varied areas as nonflammable volatile anesthetic agents, heart failure treatments, and neuromuscular blocking agents for both cardiac and thoracic surgical practice.

The First Cardiac Anesthesiology Fellow, William A. Lell: A Brief History

Fifty years ago, on August 1, 1971, William A. Lell became the first cardiac anesthesia fellow at Harvard's Massachusetts General Hospital (MGH) Department of Anesthesiology, training with the world's first group of anesthesiologists whose clinical practice, teaching, and research efforts were exclusively devoted to cardiac anesthesia. Lell's early interest in cardiovascular medicine and how mentors, particularly at the MGH, influenced his early career development are recounted. The challenges a young pioneer faced in establishing and maintaining an academic cardiac anesthesia program during the initial and rapid growth of an exciting new subspecialty are described. Dr Lell's experience emphasizes the importance of seizing new opportunities and establishing meaningful working relationships with colleagues based on mutual trust as fundamental to successful career development and research in a new medical subspecialty.

Impact of high spinal anesthesia technique on fast-track strategy in cardiac surgery: retrospective study

BACKGROUND AND OBJECTIVES

Although high spinal anesthesia (HSA) has been used in cardiac surgery, the technique has not yet been widely accepted. This retrospective study was designed to investigate the impact of HSA technique on fast-track strategy in cardiac surgery.

METHODS

Elective cardiac surgery cases (n=1025) were divided into two groups: cases with HSA combined with general anesthesia (GA) (HSA group, n=188) and cases with GA only (GA group, n=837). In the HSA group, bupivacaine and morphine were intrathecally administered immediately before GA was induced. Outcomes included fast-track extubation (less than 6 hours), extubation in the operating room, fast-track discharge from the intensive care unit (ICU) (less than 48 hours) and hospital (less than 7 days).

RESULTS

In the HSA group, 60.1% were extubated in less than 6 hours after ICU admission, as compared with 39.9% in the GA group (p<0.001). In the HSA group, 33.0% were extubated in the operating room, as compared with 4.4% in the GA group (p<0.001). LOS in the ICU was less than 48 hours in 67.6% in the HSA group, as compared with 57.2% of those in the GA group (p=0.033). LOS in the hospital was less than 7 days in 63.3% in the HSA group, as compared with 53.5% in the GA group (p=0.084).

CONCLUSIONS

HSA technique combined with GA in cardiac surgery increased the rate of fast-track extubation (less than 6 hours) when compared with GA only.

Editor’s Choice- Sedation in the coronary intensive care unit: An adapted algorithm for critically ill cardiovascular patient

In the current era, cardiovascular intensive care units care for more complex patients who are far sicker than historical post-myocardial infarction patients, and sedation has become a common intervention in these units. Current sedation best practices derive mainly from non-cardiac units which limits their generalization to the critically ill cardiac patient. Thus, a great variability in sedation protocols, especially the selection of sedative agents, is commonly seen in daily practice across cardiac units. We present an updated review on sedation in cardiovascular critical care medicine with emphasis on the hemodynamic impact. The goal of this review is to generate a general sedation algorithm specific for the cardiac patient.

Dexmedetomidine as an Anesthetic Adjuvant in Cardiac Surgery: a Cohort Study

OBJECTIVE:

α-₂-agonists cause sympathetic inhibition combined with parasympathetic activation and have other properties that could be beneficial during cardiac anesthesia. We evaluated the effects of dexmedetomidine as an anesthetic adjuvant compared to a control group during cardiac surgery.

METHODS:

We performed a retrospective analysis of prospectively collected data from all adult patients (> 18 years old) undergoing cardiac surgery. Patients were divided into two groups, regarding the use of dexmedetomidine as an adjuvant intraoperatively (DEX group) and a control group who did not receive α-₂-agonist (CON group).

RESULTS:

A total of 1302 patients who underwent cardiac surgery, either coronary artery bypass graft or valve surgery, were included; 796 in the DEX group and 506 in the CON group. Need for reoperation (2% vs. 2.8%, P=0.001), type 1 neurological injury (2% vs. 4.7%, P=0.005) and prolonged hospitalization (3.1% vs. 7.3%, P=0.001) were significantly less frequent in the DEX group than in the CON group. Thirty-day mortality rates were 3.4% in the DEX group and 9.7% in the CON group (P<0.001). Using multivariable Cox regression analysis with in hospital death as the dependent variable, dexmedetomidine was independently associated with a lower risk of 30-day mortality (odds ratio [OR]=0.39, 95% confidence interval [CI]: 0.24-0.65, P≤0.001). The Logistic EuroSCORE (OR=1.05, 95% CI: 1.02-1.10, P=0.004) and age (OR=1.03, 95% CI: 1.01-1.06, P=0.003) were independently associated with a higher risk of 30-day mortality.

CONCLUSION:

Dexmedetomidine used as an anesthetic adjuvant was associated with better outcomes in patients undergoing coronary artery bypass graft and valve surgery. Randomized prospective controlled trials are warranted to confirm our results.

Anesthesia for Bedside Procedures

Within the past 10 years, numerous short-acting anesthetic drugs have been introduced for use in the operating room. This review article will discuss the role of these agents in critically ill patients undergoing bedside procedures.

After a brief historical update, the first part of the review will focus on issues related to the pathophysiology and pharmacology of critically ill patients in general, and of specific organ dysfunction in particular. In-appropriate dosing and improper selection of agents will be highlighted. The second part of the article will discuss specific classes of drugs, with reference to their advantages and disadvantages in the ICU population.

The article will conclude by emphasizing the potency, safety, and efficacy of these drugs in significantly reducing the pain and suffering experienced by patients with critical illness.

Fast-Track Cardiac Anesthesia: Choice of Anesthetic Agents and Techniques

Fast-track cardiac anesthesia (FTCA) incorporates early tracheal extubation, decreased length of intensive care unit (ICU) and hospital stay, and (ideally) should avoid or reduce complications to safely achieve cost-savings. A growing body of evidence from randomized trials has identified many anesthetic interventions that can improve outcome after cardiac surgery. These include new short-acting hypnotic, opioid, and neuromuscular blocking drugs. An effective FTCA program requires the appropriate selection of suitable patients, a lowdose opioid anesthetic technique, early tracheal extubation, a short stay in the ICU, and coordinated perioperative care. It is also dependent on the avoidance of postoperative complications such as excessive bleeding, myocardial ischemia, low cardiac output state, arrhythmias, sepsis, and renal failure. These complications will have a much greater adverse effect on hospital length of stay and healthcare costs. A number of clinical trials have identified interventions that can reduce some of these complications. The adoption of effective treatments into clinical practice should improve the effectiveness of FTCA.

The fentanyl story

Fentanyl, introduced more than 50 years ago, has become the most often used opioid for intraoperative analgesia. Since the early 1990s the fentanyl patch has been available for management of chronic pain of all forms of cancer as well as the persistent, intense pain from many noncancerous maladies. More than a half dozen rapid-onset transmucosal fentanyl preparations have been developed, approved, launched, and popularized for "breakthrough" pain syndromes in the past 20 years. The purpose of this article is to describe why this opioid has become so important in the treatment of pain in modern clinical practice. The data indicate that fentanyl's popularity has occurred because it has minimal cardiovascular effects, does not result in increases in plasma histamine, is relatively short in onset of action and duration of effect, is easy and inexpensive to synthesize and prepare for the marketplace, and is now familiar to clinicians working in pain and perioperative medicine throughout the world.

Coronary artery bypass graft surgery: the past, present, and future of myocardial revascularisation

The development of the heart-lung machine ushered in the era of modern cardiac surgery. Coronary artery bypass graft surgery (CABG) remains the most common operation performed by cardiac surgeons today. From its infancy in the 1950s till today, CABG has undergone many developments both technically and clinically. Improvements in intraoperative technique and perioperative care have led to CABG being offered to a more broad patient profile with less complications and adverse events. Our review outlines the rich history and promising future of myocardial revascularization.

New concepts in acute pain management: strategies to prevent chronic postsurgical pain, opioid-induced hyperalgesia, and outcome measures

Chronic postsurgical pain (CPSP) is a pain syndrome that has attracted attention for more than 10 years. CPSP is a pain syndrome that develops postoperatively and lasts for at least 2 months in the absence of other causes for pain (eg, recurrence of malignancy, chronic infection, and so forth). Pain continuing from a preexisting disease is not considered as CPSP. In this article, the authors discuss the etiopathogenesis of CPSP and interventions that can help prevent and treat this condition.

Morphine is an arteriolar vasodilator in man

AIM

The mechanisms of action of morphine on the arterial system are not well understood. The aim was to report forearm vascular responses, and their mediation, to intra-arterial morphine in healthy subjects.

METHODS

Three separate protocols were performed: (i) dose ranging; (ii) acute tolerance; (iii) randomized crossover mechanistic study on forearm blood flow (FBF) responses to intrabrachial infusion of morphine using venous occlusion plethysmography. Morphine was infused either alone (study 1 and 2), or with an antagonist: naloxone, combined histamine-1 and histamine-2 receptor blockade or during a nitric oxide clamp.

RESULTS

Morphine caused an increase in FBF at doses of 30 microg min(-1)[3.25 (0.26) ml min(-1) 100 ml(-1)][mean (SEM)] doubling at 100 microg min(-1) to 5.23 (0.53) ml min(-1) 100 ml(-1). Acute tolerance was not seen to 50 microg min(-1) morphine, with increased FBF [3.96 (0.35) ml min(-1) 100 ml(-1)] (P = 0.003), throughout the 30-min infusion period. Vasodilatation was abolished by pretreatment with antihistamines (P = 0.008) and the nitric oxide clamp (P < 0.001), but not affected by naloxone. The maximum FBF with pretreatment with combined H1/H2 blockade was 3.06 (0.48) and 2.90 (0.17) ml min(-1) 100 ml(-1) after 30 min, whereas with morphine alone it reached 4.3 (0.89) ml min(-1) 100 ml(-1).

CONCLUSIONS

Intra-arterial infusion of morphine into the forearm circulation causes vasodilatation through local histamine-modulated nitric oxide release. Opioid receptor mechanisms need further exploration.

Hemodynamic effects of methadone and dihydrocodeine in overdose

BACKGROUND

Opioid overdose is an increasing health problem worldwide. The cardiovascular toxicity of opioids contributes to morbidity and mortality in overdose but the hemodynamic effects of opioids reported in animal and human studies are contradictory.

METHODS

We performed a prospective observational study of patients admitted to hospital following an overdose of methadone, dihydrocodeine, or low dose paracetamol (10 each). Basic cardiovascular indices including peripheral blood pressure, pulse rate, radial augmentation index and derived measures of aortic systolic, diastolic, pulse, and mean and end systolic pressures were measured every six hours for up to 18-23 hours after exposure or until hospital discharge.

RESULTS

Dihydrocodeine and methadone significantly reduced peripheral and aortic systolic, mean and end systolic pressures. Both opioids significantly decreased peripheral pulse pressure, but only methadone decreased aortic blood pressure. Dihydrocodeine reduced systemic and aortic diastolic blood pressure, an effect not induced by methadone. Methadone significantly reduced peripheral pulse pressure. Augmentation index and heart rate, however, did not change. Both opioids decreased arterial oxygen saturation.

CONCLUSION

These results suggest that dihydrocodeine and methadone in overdose both have a significant effect on central and peripheral hemodynamics. These effects might be expected to reduce cardiac afterload, providing a pharmacological explanation for the apparent benefit of opioids in cardiovascular diseases.