Neostigmine decreases heart rate in heart transplant patients

Sugammadex: Applications in Pediatric Critical Care

Sugammadex is a novel pharmacologic agent, which reverses neuromuscular blockade with a mechanism that differs from acetylcholinesterase inhibitors such as neostigmine. There is a growing body of literature demonstrating its efficacy in pediatric patients of all ages. Prospective trials have demonstrated a more rapid and more complete reversal of rocuronium-induced neuromuscular blockade than the acetylcholinesterase inhibitor, neostigmine. Unlike the acetylcholinesterase inhibitors, sugammadex effectively reverses intense or complete neuromuscular blockade. It may also be effective in situations where reversal of neuromuscular blockade is problematic including patients with neuromyopathic conditions or when acetylcholinesterase inhibitors are contraindicated. This article reviews the physiology of neuromuscular transmission as well as the published literature, regarding the use of sugammadex in pediatric population including the pediatric intensive care unit population. Clinical applications are reviewed, adverse effects are discussed, and dosing algorithms are presented.

Sugammadex to reverse neuromuscular blockade in a child with a past history of cardiac transplantation

Sugammadex is a novel agent for the reversal of neuromuscular blockade. The speed and efficacy of reversal with sugammadex are significantly faster than acetylcholinesterase inhibitors, such as neostigmine. Sugammadex also has a limited adverse profile when compared with acetylcholinesterase inhibitors, specifically in regard to the incidence of bradycardia. This adverse effect may be particularly relevant in the setting of a heart transplant recipient with a denervated heart. The authors present a case of an 8-year-old child, status postcardiac transplantation, who required anesthetic care for laparoscopy and lysis of intra-abdominal adhesions. Sugammadex was used to reverse neuromuscular blockade and avoid the potential adverse effects of neostigmine. The unique mechanism of action of sugammadex is discussed, previous reports of its use in this unique patient population are reviewed, and its potential benefits compared to traditional acetylcholinesterase inhibitors are presented.

Bradycardia in a Pediatric Heart Transplant Recipient: Is It the Sugammadex?

Sugammadex is a novel pharmacologic agent that is used to selectively reverse the effects of the neuromuscular blocking agents rocuronium and vecuronium. Various advantages have been reported when comparing its reversal of neuromuscular blockade to that achieved with acetylcholinesterase inhibitors (neostigmine). In heart transplant recipients, bradycardia may occur following the administration of acetylcholinesterase inhibitors, due to the denervation of the heart. Theoretically, the combination of rocuronium and sugammadex could be advantageous in this clinical scenario to avoid the potential bradycardia resulting from neostigmine administration. We present a 10-year-old male who developed profound bradycardia immediately following the administration of intravenous sugammadex. The options for reversal of neuromuscular blockade in heart transplant recipients is discussed, previous reports of bradycardia following sugammadex are presented, and the role of sugammadex in the bradycardia in our patient is reviewed.

Post-cardiac transplant recipient: Implications for anaesthesia

The annual heart transplant rate is gradually increasing worldwide. A proportion of this patient population present for an elective or emergency surgery which may or may not be related to the transplanted heart. A MEDLINE search for heart transplant, anaesthesia, adult, paediatric and surgery was conducted to review anaesthetic management for heart transplant recipients. Anaesthesia and perioperative management are different in these cases. A thorough understanding of the physiology of denervated heart, post-transplant morbidities and pharmacology of immunosuppressants is essential for best perioperative management and improved post-operative outcome.

Laparoscopic cholecystectomy in a cardiac transplant recipient

An increasing number of cardiac transplants are being carried out around the world. With increasing longevity, these patients present a unique challenge to non-transplant anesthesiologists for a variety of transplant related or incidental surgeries. The general considerations related to a cardiac transplant recipient are the physiological and pharmacological problems of allograft denervation, the side-effects of immunosuppression, the risk of infection and the potential for rejection. A thorough understanding of the physiology of a denervated heart, need for direct vasoactive agents and post-transplant morbidities is essential in anesthetic management of such a patient. Here, we describe a case of a heart transplant recipient who presented for a cholecystectomy at our center.

Patient selection in ambulatory anesthesia — An evidence-based review: part I

PURPOSE

To identify and characterize the evidence supporting decisions made in the care of patients with selected medical conditions undergoing ambulatory anesthesia and surgery. Conditions highlighted in this review include: the elderly, heart transplantation, hyper-reactive airway disease, coronary artery disease, and obstructive sleep apnea.

SOURCE

A structured search of MEDLINE (1966-2003) was performed using keywords for ambulatory surgery and patient condition. Selected articles were assigned a level of evidence using Centre for Evidence Based Medicine (CEBM) criteria. Recommendations were also graded using CEBM criteria.

PRINCIPAL FINDINGS

The elderly may safely undergo ambulatory surgery but are at increased risk for hemodynamic variation in the operating room. The heart transplant recipient is at increased risk of coronary artery disease and renal insufficiency and should undergo careful preoperative evaluation. The patient with reactive airway disease is at increased risk of minor respiratory complications and should be encouraged to quit smoking. The patient with coronary artery disease and recent myocardial infarction may undergo ambulatory surgery without stress testing if functional capacity is adequate. The patient with obstructive sleep apnea is at increased risk of difficult tracheal intubation but the likelihood of airway obstruction and apnea following ambulatory surgery is unknown.

CONCLUSION

Ambulatory anesthesia is infrequently associated with adverse outcomes, however, knowledge regarding specific patient conditions is of generally low quality. Few prospective trials are available to guide management decisions.

Anaesthetic and perioperative management of paediatric organ recipients in nontransplant surgery

The number and success rate of paediatric organ transplantation continue to improve yearly, and the number of transplanted children presenting for either elective or emergency nontransplant surgery is expected to increase accordingly. The general considerations related to any transplant recipient are the physiological and pharmacological problems of allograft denervation, the side effects of immunosuppression, the risk of infection, and the potential for rejection. Preoperative assessment of transplant recipients undergoing non-transplant surgery should focus on graft function, the risk of infection, and function of other organs. Local, regional, or general anaesthesia can be safely delivered to transplant recipients. Specific anaesthetic considerations related to the type of transplantation, have an impact directly on anaesthetic and perioperative management. Since anaesthetists and surgeons in hospitals who are not involved in transplantations, may be required to manage paediatric transplant recipients, the reviews of the existing experience in this field will be valuable tools in their hands.

Anesthetic considerations in the patient with a heart transplant

As programs to increase the awareness of organ donation grow, more patients undergo cardiac transplantation. Because immunosuppressive therapy and postoperative care are improved, the 1-year survival rate of these patients has increased to more than 80%. Not surprisingly, these patients may, either coincidentally or as a result of medications, require other procedures using anesthesia, frequently at hospitals other than the highly specialized institution that performed the transplant. Because the denervated heart responds differently than the normal heart to many perioperative drugs, physicians, including cardiologists who are frequently consulted preoperatively, must have a special awareness of the particular problems in this group of patients.

Effects of the anticholinesterase edrophonium on spectral analysis of heart rate and blood pressure variability in humans

Edrophonium, an anticholinesterase, exerts a biphasic effect on cardiovascular autonomic drive in humans (lower doses enhance; higher doses reduce). Twenty-five anesthetized, mechanically respired (10 breaths. min(-1), constant tidal volume) patients were given either saline (n = 10) or edrophonium (0.01-1.0 mg. kg(-1), n = 15) following surgery. ECG, radial arterial pressure, and respiratory rate were sampled at 250 Hz to obtain time series for consecutive R-R intervals (RRIs), and systolic (SBP) and diastolic blood pressure (DBP). A Wigner distribution was used for time frequency mapping of spectral powers at high (HFP, 0.15-0.5 Hz) and low (LFP, 0.0-0.05 Hz) frequency. Edrophonium produced a dose-dependent decrease in heart rate [baseline 66.8 +/- 1.9 (S.E.M.) beats per minute; maximum decrease to 55.8 +/- 1.4 beats per minute with 1.0 mg. kg(-1), P < 0.01]. HFP of the RRI increased at low doses (0.2-0.4 mg. kg(-1); maximum increase to 111.0 +/- 58.2% baseline; P < 0.01) but decreased (-49.5 +/- 35.5% baseline; P < 0.01) at higher (1.0 mg. kg(-1)) doses. Edrophonium had no effect on SBP and DBP. HFP of SBP decreased with increasing doses (maximal decrease to -26.2 +/- 7.5% baseline, P < 0.01, 1.0 mg. kg(-1)). LFP of SBP was also decreased (-46.3 +/- 10.9% baseline, P < 0.01, 1.0 mg. kg(-1)). Edrophonium may enhance (lower dose) or reduce (higher dose) cardiovascular autonomic drive in humans, as evidenced by the significant changes it evokes in HFP of the RRI (parasympathetic drive), and in the HFP and LFP of SBP (sympathetic drive). These observations may account for the modest autonomic side effects of edrophonium when this drug is used clinically.

Anaesthesia for patients with a transplanted organ

Increasing numbers of individuals leading normal lives have transplanted organs. They may appear in any hospital for treatment of trauma or general diseases. Common anaesthesia methods can be used for these patients, but safe conduct of anaesthesia requires knowledge of the immunosuppression, risk factors, and altered physiology or drug actions. This article reviews the anaesthesia-related literature on patients with transplanted organs.

Contractile and phosphatidylinositol responses of rat trachea to anticholinesterase drugs

PURPOSE

Some anticholinesterases (anti-ChE) such as neostigmine and pyridostigmine but not edrophonium, stimulate phosphatidylinositol (PI) response. Although a direct relationship was suggested between the increase in PI response and airway smooth muscle contraction, there are no data regarding the effects of anti-ChE drugs on airway smooth muscle. Thus, we examined the contractile properties and PI responses produced by anti-ChE drugs.

METHODS

Contractile response. Rat tracheal ring was suspended between two stainless hooks in Krebs-Henseleit (K-H) solution. (1) Carbachol (CCh), anti-ChE drugs (neostigmine, pyridostigmine, edrophonium) or DMPP (a selective ganglionic nicotinic agonist) were added to induce active contraction. (2) The effects of 4-diphenylacetoxy-N-methyl-piperidine methobromide (4-DAMP), an M3 muscarinic receptor antagonist, on neostigmine- or pyridostigmine-induced contraction of rat tracheal ring were examined. (3) Tetrodotoxin (TTX) was tested on the anti-ChE drugs-induced responses. PI response. The tracheal slices were incubated in K-H solution containing LiCl and 3[H]myo-inositol in the presence of neostigmine or pyridostigmine with or without 4-DAMP, an M3 muscarinic receptor antagonist. 3[H]inositol monophosphate (IP1) formed was counted with a liquid scintillation counter.

RESULTS

Carbachol (0.1 microM), neostigmine (1 microM), pyridostigmine (10 microM) but not edrophonium or DMPP, caused tracheal ring contraction. 4-DAMP, but not tetrodotoxin, inhibited neostigmine and pyridostigmine-induced contraction. Neostigmine- or pyridostigmine-induced IP1, accumulation was inhibited by 4-DAMP.

CONCLUSIONS

The data suggest that anti-ChE drugs activate the M3 receptors at the tracheal effector site.

Bradycardia produced by pyridostigmine and physostigmine

PURPOSE

The bradycardia produced by pyridostigmine and physostigmine in an animal model of acute cardiac denervation was examined according to its relation to cholinesterase inhibition and sensitivity to block by cholinergic receptor antagonists.

METHODS

Cats were anaesthetised, vagotomised and propranolol-treated. Heart rate was continuously recorded. Erythrocyte cholinesterase activity of arterial blood was measured using a radiometric technique. Nicotinic and muscarinic M1 receptors were blocked with hexamethonium and pirenzepine, respectively. M2 receptors were blocked with gallamine, pancuronium and AFDX-116.

RESULTS

With pyridostigmine and physostigmine the dose-response relationship for the decrease in heart rate (ED50 1.05 +/- 0.25 and 0.198 +/- 0.03 mg.kg-1, respectively) was shifted to the right of that for the inhibition of cholinesterase activity (ED50 0.094 +/- 0.03 and 0.032 +/- 0.01 mg.kg-1, respectively). The decrease in cholinesterase activity reached a plateau at a cumulative dose of 0.56 +/- 0.08 and 0.32 +/- 0.08 mg.kg-1, respectively. In contrast, there did not appear to be a plateau in the bradycardic effect. The bradycardia produced by pyridostigmine and physostigmine was blocked by hexamethonium (ED50 10 +/- 1.3 and 15.3 +/- 2.4 mg.kg-1, respectively), pirenzepine (ED50 68 +/- 16 and 138 +/- 32 micrograms.kg-1, respectively), gallamine (56 +/- 11 and 67 +/- 17 micrograms.kg-1, respectively), pancuronium (32 +/- 10 and 30 +/- 4 micrograms.kg-1, respectively), and AFDX-116 (31 +/- 4 and 28 +/- 4 micrograms.kg-1, respectively).

CONCLUSION

The bradycardia produced by reversible anticholinesterase drugs containing a carbamyl group is not clearly related to the degree of cholinesterase activity, and has a low sensitivity to nicotinic and muscarinic M1 and a high sensitivity to muscarinic M2 receptor antagonists.

Heart rate changes in cardiac transplant patients and in the denervated cat heart after edrophonium

PURPOSE

The effect of edrophonium on heart rate in cardiac transplant patients and in an animal model of acute cardiac denervation were studied, to evaluate the functional state of the peripheral parasympathetic pathway following cardiac denervation.

METHODS

Edrophonium was studied in patients with normally innervated hearts (controls) and in cardiac transplants. Edrophonium was also studied in vagotomized, beta-blocked cats. In Group I animals, the vagus nerve was not stimulated. In Groups 2 & 3 the right vagus nerve was electrically stimulated to produce approximately 20% and 40% reductions in baseline heart rate, respectively.

RESULTS

Maximum heart rate reduction in transplants (7.3 +/- 0.8 beats.min-1 with 0.6 +/- 0.08 mg.kg-1) was less than in controls (13.3 +/- 1.6 beats.min-1 with 0.4 + 0.05 mg.kg-1, P < 0.01). In Group I animals heart rate decreased maximally by 20.9 +/- 2.5 beats.min-1 with 9.0 +/- 1.9 mg.kg-1. In Groups 2 and 3, with doses < 1.5 mg.kg-1, reductions in heart rate were greater than in Group I and maximum reductions were obtained with lower doses (Group 2: maximum reduction by 20.3 +/- 2.8 beats.min-1 with 1.3 +/- 0.1 mg.kg-1; Group 3:22.6 +/- 4.0 beats.min-1 with 0.8 +/- 0.2 mg.kg-1, P < 0.001). Doses > 1.5 mg.kg-1 in Groups 2 and 3 produced increases in heart rate.

CONCLUSION

Edrophonium produced bradycardia in cardiac transplants suggesting spontaneous release of acetylcholine from parasympathetic postganglionic neurons in the transplanted heart. The magnitude of the bradycardia was less in transplant than in control patients. Findings from animal studies suggest that the reduction in transplants can be attributed to diminution or absence of tonic cardiac parasympathetic drive. At high doses, edrophonium may interfere with parasympathetic neuron activation.

Different properties of the bradycardia produced by neostigmine and edrophonium in the cat

PURPOSE

The bradycardia produced by neostigmine and edrophonium was examined according to its relation to cholinesterase inhibition and to its sensitivity to block by muscarinic receptor antagonists. For comparison, the ability of muscarinic antagonists to block the bradycardia produced by electrical stimulation of the vagus nerve was determined.

METHODS

Cats were anaesthetized, vagotomized and propranolol-treated. Heart rate was continuously recorded. Erythrocyte cholinesterase activity of arterial blood was measured using a radiometric technique. The right vagus nerve was isolated for electrical stimulation. The muscarinic antagonists used were atropine, glycopyrrolate, pancuronium, gallamine, and AFDX-116.

RESULTS

Neostigmine produced a dose-dependent decrease in cholinesterase activity which reached a plateau at a cumulative dose of 0.16 mg.kg-1 (ED50 0.009 +/- 0.003 mg.kg-1). Neostigmine produced a dose-dependent decrease in heart rate with the dose-response relationship (ED50 0.1 +/- 0.01 mg.kg-1; P = 0.0006) shifted to the right of that for the inhibition of cholinesterase activity. In contrast to the anticholinesterase effect, the bradycardic effect did not reach a plateau and continued to increase even at doses at which the cholinesterase inhibition was maximal. The maximal decrease in heart rate when the heart was still in sinus rhythm was by 81 +/- 13 bpm (49 +/- 7% of baseline), which was produced by a dose of 0.32 mg.kg-1. Edrophonium produced dose-dependent decreases in cholinesterase activity and heart rate, which were highly correlated (correlation coefficient r = 0.99, P < 0.0001). The ED50 of the reduction in heart rate (0.9 +/- 0.18 mg.kg-1) and cholinesterase activity (0.89 +/- 0.12 mg.kg-1) produced by edrophonium were similar. Moreover, the reduction in heart rate and cholinesterase activity produced by edrophonium reached a plateau at the same dose (6.4 mg.kg-1). At this dose, heart rate decreased by 22 +/- 2 bpm (14.6 +/- 0.9% of baseline). Compared to the bradycardia produced by stimulation of the vagus nerve, that produced by neostigmine was blocked by muscarinic antagonists at significantly lower doses while that produced by edrophonium was blocked at similar doses.

CONCLUSIONS

The neostigmine-induced bradycardia is poorly correlated with cholinesterase inhibition compared to that produced by edrophonium, and has a higher sensitivity to muscarinic receptor antagonists compared to that produced by edrophonium or vagus nerve stimulation. These results are consistent with the hypothesis that the neostigmine-induced bradycardia is, in part, the result of neostigmine directly activating cholinergic receptors within the cardiac parasympathetic pathway. The bradycardia produced by edrophonium may be accounted for solely by an anticholinesterase action.

Neostigmine-induced bradycardia following recent vs remote cardiac transplantation in the same patient

PURPOSE

This report describes the effects of neostigmine on heart rate in the same patient following recent and remote cardiac transplantation.

CLINICAL FEATURES

Eighty-six months following the first transplant, neostigmine 5.0 micrograms.kg-1 i.v. produced a 10% reduction in heart rate which was reversed by atropine 1.2 mg. For 24 months prior to this initial study, the patient experienced angina, suggesting cardiac afferent reinnervation. Three months after the second heart transplant, a second study showed that a six-fold increase in the dose of neostigmine, 30.0 micrograms.kg-1, only produced a 3.5% reduction in heart rate which was reversed by atropine 1.2 mg.

CONCLUSIONS

These observations indicate that neostigmine produces bradycardia following cardiac transplantation, and suggest that a greater response may be observed in remotely than in recently transplanted patients.