An epidural scoring scale for arm movements (ESSAM) in patients receiving high thoracic epidural analgesia for coronary artery bypass grafting

Indoleamine-2,3-Dioxygenase as a Perioperative Marker of the Immune System

Indoleamine-2,3-dioxygenase (IDO) is the “rate-limiting” enzyme in the kynurenine (Kyn) pathway of the tryptophan (Trp) catabolism. By its immune-modulatory effect, IDO initiates changes to the physiologically balanced immune state and plays a key role in the pathogenesis of various diseases, as well as in the perioperative setting during surgery. In autoimmune processes, highly malignant cancers such as glioblastoma or organ transplantation, IDO’s involvement has been studied extensively. However, in severe systemic infections, as present in sepsis, it is not yet completely understood. Hereafter, in this narrative review, we present the current knowledge of IDO’s implication on such complex immune-related processes. Moreover, we address the role of IDO as a predictive biomarker as well as a therapeutic target for immune-mediated diseases. Finally, we discuss IDO in the setting of surgical trauma-induced stress and highlight its promising use as a biomarker in the pre-operative setting for all disciplines involved in the decision-making process and treatment of patients undergoing surgery.

Biventricular function in exercise during autonomic (thoracic epidural) block

BACKGROUND

Blockade of cardiac sympathetic fibers by thoracic epidural anesthesia (TEA) was previously shown to reduce right and left ventricular systolic function and effective pulmonary arterial elastance. At conditions of constant paced heart rate, cardiac output and systemic hemodynamics were unchanged. In this study, we further investigated the effect of cardiac sympathicolysis during physical stress and increased oxygen demand.

METHODS

In a cross-over design, 12 patients scheduled to undergo thoracic surgery performed dynamic ergometric exercise tests with and without TEA. Hemodynamics were monitored and biventricular function was measured by transthoracic two-dimensional and M-mode echocardiography, pulsed wave Doppler and tissue Doppler imaging.

RESULTS

TEA attenuated systolic RV function (TV S': - 21%, P < 0.001) and LV function (MV S': - 14%, P = 0.025), but biventricular diastolic function was not affected. HR (- 11%, P < 0.001), SVI (- 15%, P = 0.006), CI (- 21%, P < 0.001) and MAP (- 12%, P < 0.001) were decreased during TEA, but SVR was not affected. Exercise resulted in significant augmentation of systolic and diastolic biventricular function. During exercise HR, SVI, CI and MAP increased (respectively, + 86%, + 19%, + 124% and + 17%, all P < 0.001), whereas SVR decreased (- 49%, P < 0.001). No significant interactions between exercise and TEA were found, except for RPP (P = 0.024) and MV E DT (P = 0.035).

CONCLUSION

Cardiac sympathetic blockade by TEA reduced LV and RV systolic function but did not significantly blunt exercise-induced increases in LV and RV function. These data indicate that additional mechanisms besides those controlled by the cardiac sympathetic nervous system are involved in the regulation of cardiac function during dynamic exercise. Trial registration Clinical trial registration: Nederlands Trial Register, NTR 4880 http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4880 .

Upper thoracic epidural anaesthesia: effects of age on neural blockade and cardiovascular parameters

BACKGROUND

Segmental dose reduction with increasing age after thoracic epidural anaesthesia (TEA) has been documented. We hypothesised that after a fixed loading dose of ropivacaine at the T3-T4 level, increasing age would result in more extended analgesic spread. In addition, other aspects of neural blockade and haemodynamic changes were studied.

METHODS

Thirty-five lung surgery patients were included in three age groups. Thirty-one patients received an epidural catheter at the T3-T4 interspace followed by an injection of 8-ml ropivacaine 0.75%. Analgesia was assessed with pinprick and temperature discrimination. Motor block was tested using the Bromage and epidural scoring scale for arm movements score. An arterial line was inserted for invasive measurement of blood pressure, cardiac index (CI) and stroke volume (SV).

RESULTS

There was no influence of age on quality of TEA except for the caudal border of analgesia being somewhat lower in the middle and older age group compared with the young age group. Heart rate (6.0 ± 5.9, P < 0.001), mean arterial pressure (16.1 ± 15.6, P < 0.001), CI (0.55 ± 0.49, P < 0.001) and SV (9.6 ± 14.6, P = 0.001) decreased after TEA for the total group. Maximal reduction in heart rate after TEA was more extensive in the young age group compared with the other age groups. There was no effect of age on other cardiovascular parameters.

CONCLUSION

We were unable to demonstrate an effect of age on the maximal number of spinal segments blocked after TEA; however, the caudad spread of analgesia increased with advancing age. In addition, reduction of heart rate was greater in the youngest group.

Regional anaesthesia for carotid endarterectomy: an audit over 10 years

BACKGROUND

The aim of this retrospective study was to compare the failure rates and the frequency of anaesthesia-related complications of two different methods of regional anaesthesia used for carotid endarterectomy--cervical epidural (CE) anaesthesia and cervical plexus block (CPB).

METHODS

The study included 1828 carotid endarterectomies performed in 1455 patients between 1996 and 2006. A combination of deep and superficial CPB was used for 1166 procedures, whereas in 662 cases surgery was performed under CE anaesthesia.

RESULTS

The failure rate of CPB was 3% compared with 6.9% for CE anaesthesia (P < 0.0001). The reasons for failure of the anaesthetic techniques were (1) technical failure, (2) insufficient analgesia, (3) non-compliant patients, and (4) anaesthetic complications. The incidence of complications resulting from CE anaesthesia was significantly higher than with CPB; life-threatening complications--2% compared with 0.3% (P < 0.0001); other anaesthesia-related complications 5.7 vs 4.7%. Serious complications included inadvertant injection into the subarachnoid space or vertebral artery. The frequency of shunt insertion, perioperative stroke, and death from any cause was similar in both groups of patients.

CONCLUSIONS

Both methods of regional anaesthesia are acceptable for carotid artery surgery. CPB is associated with a significantly lower frequency of anaesthesia-related complications and should therefore be considered the anaesthetic of choice. CE anaesthesia should not be performed except in extenuating circumstances such as variant anatomy or the requirement for more extensive surgery.

The effect of high thoracic epidural anesthesia on systolic and diastolic left ventricular function in patients with coronary artery disease

In patients with coronary artery disease, vasoconstriction is induced through activation of the sympathetic nervous system. Both alpha1- and alpha2-adrenergic epicardial and microvascular constriction are potent initiators of myocardial ischemia. Attenuation of ischemia has been observed when sympathetic nervous system activity is inhibited by high thoracic epidural anesthesia (HTEA). However, it is still a matter of controversy whether establishing HTEA may correspondingly translate into an improvement of left ventricular (LV) function. To clarify this issue, LV function was quantified serially before and after HTEA using a new combined systolic/diastolic variable of global LV function (myocardial performance index [MPI]) and additional variables that more specifically address systolic (e.g., fractional area change) or diastolic function (e.g., intraventricular flow propagation velocity [Vp]). High thoracic epidural catheters were inserted in 37 patients scheduled for coronary artery surgery, and HTEA was administered in the awake patients. Echocardiographic and hemodynamic measures were recorded before and after institution of HTEA. HTEA induced a significant improvement in diastolic LV function (e.g., Vp changed from 45.1 +/- 16.1 to 53.8 +/- 18.8 cm/s; P < 0.001), whereas indices of systolic function did not change. The change in the diastolic characteristics caused the MPI to improve from 0.51 +/- 0.13 to 0.35 +/- 0.13 (P < 0.001). We conclude that an improvement in cardiac function was due to improved diastolic characteristics.

Comparison of three anesthetic techniques for off-pump coronary artery bypass grafting: General anesthesia, combined general and high thoracic epidural anesthesia, or high thoracic epidural anesthesia alone

OBJECTIVE

This study compared general anesthesia (GA), combined GA plus thoracic epidural anesthesia (TEA), and TEA alone in patients scheduled for off-pump coronary artery bypass grafting.

DESIGN

Prospective, nonrandomized clinical study

SETTING

University hospital.

PARTICIPANTS

Ninety consenting patients undergoing beating-heart coronary artery revascularization with comparable coronary status and left ventricular function.

INTERVENTIONS

GA (n=30) was conducted with propofol, remifentanil, and cisatracurium or combined with TEA (GA+TEA, n=30) or TEA as the sole anesthetic with ropivacaine plus sufentanil (TEA, n=30).

MEASUREMENTS AND MAIN RESULTS

Groups were comparable regarding the surgical approaches and the number of anastomoses. Four patients (GA, n=2; GA+TEA, n=2) who required unplanned cardiopulmonary bypass, and 4 patients in the TEA group who underwent unexpected intubation because of pneumothorax (n=2), phrenic nerve palsy, or incomplete analgesia were excluded from further analysis. Intraoperative heart rate decreased significantly with both GA+TEA and TEA. None of the patients with TEA alone was admitted to the intensive care unit, they all were monitored on average for 6 hours postoperatively in the intermediate care unit and allowed to eat and drink as desired on admission. Postoperative pain scores were lower in both groups with TEA. There were no differences among groups in patients overall satisfaction.

CONCLUSION

Based on the authors data, all anesthetic techniques were equally safe from the clinicians standpoint. However, GA+TEA appeared to be most comprehensive, allowing for revascularization of any coronary artery, providing good hemodynamic stability and reliable postoperative pain relief. Nonetheless, the actual and potential risks of TEA during cardiac surgery should not be underestimated.

Extended Thymectomy in Patients with Myasthenia Gravis with High Thoracic Epidural Anesthesia Alone

Successful extended thymectomy was performed in three patients with myasthenia gravis under only high thoracic epidural anesthesia with voluntary breathing. It was not necessary to intubate a tracheal tube during operation for any of the patients. Neither muscle relaxants nor volatile anesthetic agents were required. The mean operating time was 2.0 +/- 0.5 hours. The drainage tubes were removed the day after operation in all patients. In two patients the arterial oxygen saturation (SaO2) and the arterial partial pressure of carbon dioxide (PaCO2) and oxygen (PaO2) were stable; in the third patient the SaO2 was temporarily decreased to 92 mmHg when bilateral mediastinal pleura were opened. The right pleural defect was then covered with a large wet towel, which was pressed on the defect, and thoracic drainage was performed. The left pleural defect was repaired with 3-0 Vicryl after suctioning the air in the pleural space, after which the SaO2 recovered. All patients were able to drink water and walk within 1 hour after the operation. This procedure is advantageous in that the use of muscle relaxants and volatile anesthetic agents prevented the laryngeal injury that results from translaryngeal intubation; in turn we avoided causing postoperative respiratory insufficiency. This may be suitable for the operation of some patients with MG, but further studies are required to define the indication.

High thoracic epidural anesthesia for coronary artery bypass grafting using two different surgical approaches in conscious patients

Recent developments in coronary artery bypass graft surgery (CABG) without cardiopulmonary bypass made the sole use of high thoracic epidural anesthesia (TEA) in conscious patients feasible. Previously, TEA has been reported only for single-vessel CABG via lateral thoracotomy. We investigated the feasibility and complications of sole TEA in 20 patients undergoing beating-heart arterial revascularization via partial lower sternotomy for single-vessel disease (minimally invasive direct coronary artery bypass grafting [MIDCAB] technique; n = 10) or complete median sternotomy for multivessel disease (off-pump coronary artery bypass grafting [OPCAB] technique; n = 10). An epidural catheter was inserted at the T1-2 or T2-3 interspace. An epidural infusion of ropivacaine 0.5% and sufentanil 1.66 micro g/mL was started to establish anesthetic levels at C5-6 for OPCAB and at T1-2 for MIDCAB. Nine OPCAB and eight MIDCAB procedures were completed while patients were awake and spontaneously breathing during the entire procedure. Because of surgical pneumothorax (OPCAB), insufficient anesthesia, or phrenic nerve palsy (both MIDCAB), three patients required intraoperative conversion to general anesthesia. The heart rate decreased significantly (P < 0.05) by 10%-15% in both groups during the procedure. Compared with baseline (B), mean arterial blood pressure (mm Hg) was decreased significantly only during coronary anastomosis (CA) (B(OPCAB), 95 +/- 11; CA(OPCAB), 68 +/- 9; B(MIDCAB), 86 +/- 10; CA(MIDCAB), 73 +/- 10; P not significant between groups). PaCO(2) increased from 42 +/- 2 mm Hg to 46 +/- 7 mm Hg (P < 0.05) throughout the perioperative course during OPCAB, whereas it remained almost unaltered during MIDCAB procedures. All patients rated TEA as "good" or "excellent." In conclusion, we demonstrated that the sole use of TEA for MIDCAB and OPCAB procedures was feasible and provided a high degree of patient satisfaction in our small and highly selected cohorts. IMPLICATIONS. The sole use of high thoracic epidural anesthesia was studied in 20 patients who underwent beating-heart coronary artery bypass grafting using either median or partial lower sternotomy while awake.