Thoracic epidural analgesia: its role in postthoracotomy atrial arrhythmias

Sympathetic Nervous System Activation and Its Modulation: Role in Atrial Fibrillation

The autonomic nervous system (ANS) has a significant influence on the structural integrity and electrical conductivity of the atria. Aberrant activation of the sympathetic nervous system can induce heterogeneous changes with arrhythmogenic potential which can result in atrial tachycardia, atrial tachyarrhythmias and atrial fibrillation (AF). Methods to modulate autonomic activity primarily through reduction of sympathetic outflow reduce the incidence of spontaneous or induced atrial arrhythmias in animal models and humans, suggestive of the potential application of such strategies in the management of AF. In this review we focus on the relationship between the ANS, sympathetic overdrive and the pathophysiology of AF, and the potential of sympathetic neuromodulation in the management of AF. We conclude that sympathetic activity plays an important role in the initiation and maintenance of AF, and modulating ANS function is an important therapeutic approach to improve the management of AF in selected categories of patients. Potential therapeutic applications include pharmacological inhibition with central and peripheral sympatholytic agents and various device based approaches. While the role of the sympathetic nervous system has long been recognized, new developments in science and technology in this field promise exciting prospects for the future.

Thoracic epidural analgesia reduces myocardial injury in ischemic patients undergoing major abdominal cancer surgery

Background and objectives

Major abdominal cancer surgeries are associated with significant perioperative mortality and morbidity due to myocardial ischemia and infarction. This study examined the effect of perioperative patient controlled epidural analgesia (PCEA) on occurrence of ischemic cardiac injury in ischemic patients undergoing major abdominal cancer surgery.

Patients and methods

One hundred and twenty patients (American Society of Anesthesiologists grade II and III) of either sex were scheduled for elective upper gastrointestinal cancer surgeries. Patients were allocated randomly into two groups (60 patients each) to receive, besides general anesthesia: continuous intra and postoperative intravenous (IV) infusion with fentanyl for 72 h postoperatively (patient controlled intravenous analgesia [PCIA] group) or continuous intra and postoperative epidural infusion with bupivacaine 0.125% and fentanyl (PCEA group) for 72 h postoperatively. Perioperative hemodynamics were recorded. Postoperative pain was assessed over 72 h using visual analog scale (VAS). All patients were screened for occurrence of myocardial injury (MI) by electrocardiography, echocardiography, and cardiac troponin I serum level. Other postoperative complications as arrhythmia, deep venous thrombosis (DVT), pulmonary embolism, pneumonia, and death were recorded.

Results

There was a significant reduction in overall adverse cardiac events (myocardial injury, arrhythmias, angina, heart failure and nonfatal cardiac arrest) in PCEA group in comparison to PCIA group. Also, there was a significant reduction in dynamic VAS pain score in group PCEA in comparison to PCIA at all measured time points. Regarding perioperative hemodynamics, there was a significant reduction in intra-operative mean arterial pressure (MAP); and heart rate in PCEA group in comparison to PCIA group at most of measured time points while there was not a significant reduction in postoperative MAP and heart rate in the second and third postoperative days. The incidence of other postoperative complications such as DVT, pneumonia and in hospital mortality were decreased in PCEA group.

Conclusion

Perioperative thoracic epidural analgesia in patients suffering from coronary artery disease subjected to major abdominal cancer surgery reduced significantly postoperative major adverse cardiac events with better pain control in comparison with perioperative IV analgesia.

Association of thoracic epidural analgesia with risk of atrial arrhythmias after pulmonary resection: a retrospective cohort study

PURPOSE

Atrial arrhythmias are common after non-cardiac thoracic surgery. We tested the hypothesis that TEA reduces the risk of new-onset atrial arrhythmias after pulmonary resection.

METHODS

We evaluated patients who had pulmonary resection. New-onset atrial arrhythmias detected before hospital discharge was our primary outcome. Secondary outcomes included other cardiovascular complications, pulmonary complications, time-weighted average pain score over 72 h, and duration of hospitalization. Patients with combination of general anesthesia and TEA were matched on propensity scores with patients given general anesthesia only. The matched groups were compared by use of logistic regression, linear regression, or Cox proportional hazards regression, as appropriate.

RESULTS

Among 1,236 patients who had pulmonary resections, 937 received a combination of general anesthesia and TEA (TEA) and 299 received general anesthesia only (non-TEA). We successfully matched 311 TEA patients with 132 non-TEA patients. We did not find a significant association between TEA and postoperative atrial arrhythmia (odds ratio (95 % CI) of 1.05 (0.50, 2.19), P = 0.9). TEA was not significantly associated with length of hospital stay or postoperative pulmonary complications (odds ratio (95 % CI) of 0.71 (0.22, 2.29), P = 0.47). TEA patients experienced fewer postoperative cardiovascular complications; although the association was not statistically significant (odds ratio (95 % CI) of 0.30 (0.06, 1.45), P = 0.06). Time-weighted average pain scores were similar in the two groups.

CONCLUSION

TEA was not associated with reduced occurrence of postoperative atrial arrhythmia. Although postoperative pulmonary complications were similar with and without TEA, TEA patients tended to experience fewer cardiovascular complications.

The effectiveness of preemptive thoracic epidural analgesia in thoracic surgery

BACKGROUND

The aim of this study is to investigate the effectiveness of preemptive thoracic epidural analgesia (TEA) comparing conventional postoperative epidural analgesia on thoracotomy.

MATERIAL AND METHODS

Forty-four patients were randomized in to two groups (preemptive: Group P, control: Group C). Epidural catheter was inserted in all patients preoperatively. In Group P, epidural analgesic solution was administered as a bolus before the surgical incision and was continued until the end of the surgery. Postoperative patient controlled epidural analgesia infusion pumps were prepared for all patients. Respiratory rates (RR) were recorded. Patient's analgesia was evaluated with visual analog scale at rest (VASr) and coughing (VASc). Number of patient's demands from the pump, pump's delivery, and additional analgesic requirement were also recorded.

RESULTS

RR in Group C was higher than in Group P at postoperative 1st and 2nd hours. Both VASr and VASc scores in Group P were lower than in Group C at postoperative 1st, 2nd, and 4th hours. Patient's demand and pump's delivery count for bolus dose in Group P were lower than in Group C in all measurement times. Total analgesic requirements on postoperative 1st and 24th hours in Group P were lower than in Group C.

CONCLUSION

We consider that preemptive TEA may offer better analgesia after thoracotomy.

Supraventricular arrhythmias after thoracotomy: is there a role for autonomic imbalance?

Supraventricular arrhythmias are common rhythm disturbances following pulmonary surgery. The overall incidence varies between 3.2% and 30% in the literature, while atrial fibrillation is the most common form. These arrhythmias usually have an uneventful clinical course and revert to normal sinus rhythm, usually before patent's discharge from hospital. Their importance lies in the immediate hemodynamic consequences, the potential for systemic embolization and the consequent long-term need for prophylactic drug administration, and the increased cost of hospitalization. Their incidence is probably related to the magnitude of the performed operative procedure, occurring more frequently after pneumonectomy than after lobectomy. Investigators believe that surgical factors (irritation of the atria per se or on the ground of chronic inflammation of aged atria), direct injury to the anatomic structure of the autonomic nervous system in the thoracic cavity, and postthoracotomy pain may contribute independently or in association with each other to the development of these arrhythmias. This review discusses currently available information about the potential mechanisms and risk factors for these rhythm disturbances. The discussion is in particular focused on the role of postoperative pain and its relation to the autonomic imbalance, in an attempt to avoid or minimize discomfort with proper analgesia utilization.

Thoracic epidural analgesia in post-thoracotomy patients: comparison of three different concentrations of levobupivacaine and sufentanil

BACKGROUND

Relative effects of dosage, volume and concentration of local anaesthetics used for postoperative thoracic epidural analgesia are still under debate. In this randomized, prospective, double-blinded study, we evaluated the incidence of side-effects such as changes in arterial pressure, postoperative nausea, vomiting, and pruritus in patients admitted for thoracic surgery during continuous thoracic epidural infusion using levobupivacaine and sufentanil mixture in three different volumes.

METHODS

We studied 150 patients who underwent thoracotomy with a thoracic epidural catheter placed between T4 and T7. The patients were randomized into three groups which received 10 mg h(-1) of levobupivacaine at three different concentrations (0.5%, 0.25%, and 0.15%), in combination with sufentanil at 2.6 microg h(-1). Haemodynamic effects, pruritus, nausea, vomiting, sensory and motor block, pain score, additional analgesic requirement, sedation, and patient satisfaction were registered immediately after the surgical operation and on the first, second, and third postoperative days.

RESULTS

We did not detect any differences in the incidence of side-effects such as changes in arterial pressure, and also postoperative nausea, vomiting, and pruritus. The three groups were also similar with regard to patient characteristics, sensory and motor block, pain score, analgesic rescue dose, sedation, and patient satisfaction.

CONCLUSIONS

The same dose of a mixture of levobupivacaine and sufentanil administered in three different volumes and concentrations during continuous thoracic epidural infusion for thoracotomy provided an equal incidence of adverse haemodynamic effects, nausea, vomiting, or pruritus.

Perioperative anesthetic management for esophagectomy

Esophageal resection is a formidable operation associated with high morbidity and mortality. Anesthetic management may contribute to the containment of respiratory failure and anastomotic leakage by the use of thoracic epidural analgesia, protective ventilation strategies, prevention of tracheal aspiration, and judicious fluid management.

Risk factors for an intraoperative arrhythmia during esophagectomy

PURPOSE

Arrhythmias after an esophagectomy (most commonly atrial fibrillation) are a significant contributing factor to patient morbidity. However, the significance of an intraoperative arrhythmia is not completely understood. The aim of this retrospective study was to determine the occurrence and risk factors for developing intraoperative arrhythmias in patients undergoing an esophagectomy.

MATERIALS AND METHODS

We reviewed the records of 427 patients who underwent a transthoracic esophagectomy between 2001 and 2005. Variables such as age, sex, hypertension, diabetes, cardiac disease, preoperative pulmonary function test (PFT) results, cancer level, combined radiochemotherapy, intrathoracic cavity adhesions and anastomosis site, hemoglobin, central venous pressure (CVP), fluid balance, serum potassium level, dose of vasopressors, temperature, and combined general and epidural anesthesia were analyzed as risk factors for the occurrence of an arrhythmia. We defined this arrhythmia as one not originating from the sinus node.

RESULTS

The incidence of intraoperative arrhythmia in this subset of patients was 17.1%, with a 37.2% reoccurrence rate during the first three postoperative days. Univariate and multivariate analysis revealed the presence of heart disease, poor PFTs, cervical anastomosis, elevated CVP, and higher ephedrine doses to be independent predictors of the development of an intraoperative arrhythmia.

CONCLUSION

The incidence of intraoperative arrhythmia during esophagectomy was 17.1% with a 37.2% of reoccurrence rate.

Bupivacaine, but not lidocaine, disrupts cardiolipin-containing small biomimetic unilamellar liposomes

Inadvertent intravenous administration of bupivacaine, unlike that of lidocaine, is associated with significant cardiotoxicity. However, the mechanism(s) underlying this phenomenon is uncertain. High concentrations of cardiolipin, an anionic phospholipid, are found in the mitochondria membrane of cardiomyocytes. We hypothesized that bupivacaine, but not lidocaine, interacts avidly with cardiolipin in the mitochondria membrane of cardiomyocytes and alters its integrity thereby accounting, in part, for cardiotoxicity. Accordingly, the purpose of this study was to begin to address this issue by determining the effects of bupivacaine and lidocaine on permeability of cardiolipin-containing biomimetic small unilamellar liposomes. We found that bupivacaine, but not lidocaine, elicited a significant, concentration-dependent increase in carboxyfluorescein release from cardiolipin-containing small unilamellar liposomes (size, 165nm) composed of egg yolk phosphatidylcholine and cholesterol (p<0.05). Both drugs had no significant effects on carboxyfluorescein release from liposomes devoid of cardiolipin (p>0.5). Collectively, these data indicate that bupivacaine, but not lidocaine, interacts avidly and selectively with biomimetic small unilamellar liposomes containing cardiolipin and disrupts their integrity. We suggest that these interactions underlie, in part, bupivacaine-induced cardiotoxicity.

Pain management strategies for patients undergoing extrapleural pneumonectomy

The role of anesthetic or analgesic technique in outcome remains controversial. The choice of anesthetic and postoperative analgesic plan plays a small, albeit important, role in perioperative care and a multimodal rehabilitation program. Pulmonary complications are the most important cause of morbidity and mortality after EPP. There is increasing evidence that TEA with local anesthetic agents and opioids is superior for the control of dynamic pain, plays a key role in early extubation and mobilization, reduces postoperative pulmonary complications, and has the potential to decrease the incidence of PTPS.