Haemodynamic effects of thoracic epidural anaesthesia during induction of anaesthesia: an investigation into the effects of tracheal intubation during target-controlled infusion of propofol

[Effects of thoracic epidural administration of lidocaine on hemodynamic and arousal responses of double lumen tracheal intubation during induction of anesthesia]

OBJECTIVE

To compare the effects of thoracic epidural administration of lidocaine on hemodynamic and arousal responses of double lumen tracheal intubation during induction of anesthesia.

METHODS

In the study, 40 patients with American Society of Anesthesiologists (ASA) physical statuses I-II, aged 19-66 years, scheduled for elective thoracic surgeries under general anesthesia requiring orotracheal intubation were allocated to either the double-lumen endobronchial intubation (T group) or double-lumen endobronchial intubation after epidural administration of lidocaine (E group). After an intravenous anesthetic induction, the orotracheal double-lumen intubation was performed using a Macintosh direct laryngoscopy (MDLS), respectively. Invasive blood pressure (BP), heart rate (HR) and bispectral index (BIS) were recorded before and after anesthetic induction, immediately after intubation and 5 minutes after intubation with 1-minute interval and the intubation time also noted. The rate pressure product (RPP) was calculated.

RESULTS

After anesthetic induction, BP and RPP in the two groups decreased significantly compared with their preinduction values. In comparison with their postinduction values, the orotracheal intubation in the two groups caused significant increases in BPs, HRs and RPP. In comparison with their preinduction values, BPs decreased significantly in E group, systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) increased significantly and lasted for 1 min in T group. The HRs of both groups after intubation were significantly higher than their baseline values , and increased in HR and lasted for 1 min and 4 min in E group and T group, respectively. SBP, DBP, MAP, HR and RPP after intubation in T group were significantly higher than those of E group during the observation period. The values of BIS were similar between both the groups. In T group, the incidences of SBP percent increased>30% of the baseline value and RPP more than 22 000 were significantly higher than in E group. None of the patients in group E had SBP more than 130% of the baseline value and RPP more than 22 000.

CONCLUSION

During double-lumen endobronchial intubation, epidural administration of lidocaine can provide less hemodynamic response and similar arousal response.

Effects of Thoracic Epidural Anesthesia on Neuronal Cardiac Regulation and Cardiac Function

Cardiac sympathetic blockade with high-thoracic epidural anesthesia is considered beneficial in patients undergoing major surgery because it offers protection in ischemic heart disease. Major outcome studies have failed to confirm such a benefit, however. In fact, there is growing concern about potential harm associated with the use of thoracic epidural anesthesia in high-risk patients, although underlying mechanisms have not been identified. Since the latest review on this subject, a number of clinical and experimental studies have provided new information on the complex interaction between thoracic epidural anesthesia–induced sympatholysis and cardiovascular control mechanisms. Perhaps these new insights may help identify conditions in which benefits of thoracic epidural anesthesia may not outweigh potential risks. For example, cardiac sympathectomy with high-thoracic epidural anesthesia decreases right ventricular function and attenuates its capacity to cope with increased right ventricular afterload. Although the clinical significance of this pathophysiologic interaction is unknown at present, it identifies a subgroup of patients with established or pending pulmonary hypertension for whom outcome studies are needed. Other new areas of interest include the impact of thoracic epidural anesthesia–induced sympatholysis on cardiovascular control in conditions associated with increased sympathetic tone, surgical stress, and hemodynamic disruption. It was considered appropriate to collect and analyze all recent scientific information on this subject to provide a comprehensive update on the cardiovascular effects of high-thoracic epidural anesthesia and cardiac sympathectomy in healthy and diseased patients.

Effects of General-epidural Anaesthesia on Haemodynamics in Patients with Myasthenia Gravis

OBJECTIVE

The current study aims to explore the effects of general-epidural anaesthesia (GEA) on the perioperative haemodynamics in patients with myasthenia gravis (MG), as well as their extubation time.

METHODS

A total of 42 MG patients (Ossermann I-II b types) receiving elective total thymectomy were randomized into GEA (n = 20) and general anaesthesia alone (GA; n = 22) groups. Changes in their mean arterial pressure (MAP) and heart rate (HR) were recorded before anesthesia and at the time of intubation, skin incision, sternotomy and extubation. Dosages of general anaesthetics during time unit and the time of extubation and complete recovery from the ending of the operation were also recorded.

RESULTS

After anaesthesia, both groups displayed increased MAPs and HRs, with those in the GA group significantly higher than those in the GEA group (p < 0.05). The total consumption of general anaesthetics in the GA group was markedly higher than that in the GEA group (p < 0.01).

CONCLUSION

The GEA group had shorter postoperative extubation and recovery time than the GA group (p < 0.01). General-epidural anaesthesia stabilizes perioperative haemodynamics, reduces the consumption of general anaesthetics and shortens extubation time. It is a feasible and ideal anaesthetic method at present.

Combined general/epidural anesthesia (ropivacaine 0.375%) versus general anesthesia for upper abdominal surgery

BACKGROUND

We designed this study to investigate the effect of 0.375% ropivacaine on stress hormone responses and anesthetic requirements in combined epidural/general anesthesia for nephrectomy.

METHODS

Thirty-two adults, ASA physical status I-II, undergoing nephrectomy lasting about 2 h for renal carcinoma were randomly assigned to one of two groups: epidural (saline)/general anesthesia (group C) and epidural (0.375% ropivacaine)/general (group R) anesthesia. Induction of anesthesia was performed with target-controlled infusion sufentanil and propofol titrated to achieve bispectral index score (define) between 40 and 50. Endotracheal intubation was facilitated by the target-controlled infusion administration of vecuronium. After intubation, anesthesia was maintained with propofol infusion titrated to maintain bispectral index between 40 and 50. The target concentration of sufentanil was titrated according to arterial blood pressure and heart rate. Plasma samples were taken immediately before, 2 min after tracheal intubation, immediately after incision, immediately after the initiation of celiac exploration, 1 h after operation, and immediately after tracheal extubation for measurements of epinephrine, glucose, and cortisol in both groups.

RESULTS

The relative changes of plasma concentrations of glucoses and cortisol were higher at 1 h after operation and immediately after extubation in group C when compared with group R. The plasma concentrations of epinephrine in both groups were similar. The requirements of propofol for induction and maintenance of anesthesia were not statistically different in the groups, but the requirement of sufentanil during maintenance was significant reduced in group R (P < 0.05).

CONCLUSIONS

Epidural ropivacaine 0.375% suppressed stress hormone responses and sufentanil requirements perioperatively during maintenance of anesthesia for nephrectomy.

Comparison of 1.5% lidocaine and 0.5% ropivacaine epidural anesthesia combined with propofol general anesthesia guided by bispectral index

OBJECTIVE

To compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness (LOC), effect-site propofol concentrations, and the hemodynamic variables during induction of general anesthesia guided by bispectral index (BIS) were studied.

METHODS

Forty-five patients were divided into three groups to receive epidurally administered saline (Group S), 1.5% (w/w) lidocaine (Group L), or 0.5% (w/w) ropivacaine (Group R). Propofol infusion was started to produce blood concentration of 4 mug/ml. Once the BIS value reached 40~50, endotracheal intubation was facilitated by 0.1 mg/kg vecuronium. Measurements included the time to LOC, effect-site propofol concentrations, total propofol dose, mean arterial blood pressure (MABP), and heart rate (HR) at different study time points.

RESULTS

During induction of anesthesia, both Groups L and R were similar for the time to LOC, effect-site propofol concentrations, total propofol dose, MABP, HR, and BIS. The total doses of propofol administered until 1 min post-intubation were significantly less in patients of Groups R and L compared with Group S. MABP and HR were significantly lower following propofol induction compared with baseline values in the three groups, or MABP was significantly increased following intubation as compared with that prior to intubation in Group S but not in Groups R and L while HR was significantly increased following intubation in the three groups.

CONCLUSION

Epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine has similar effects on the time to LOC, effect-site propofol concentrations, total propofol dose, and the hemodynamic variables during induction of general anesthesia.

Effects of epidural anesthesia with 0.2% and 1% ropivacaine on predicted propofol concentrations and bispectral index values at three clinical end points

STUDY OBJECTIVE

To compare the effects of 0.2% epidural ropivacaine and those of 1% epidural ropivacaine on predicted propofol concentrations and bispectral index scores (BISs) at three clinical end points.

DESIGN

Randomized double-blind study.

SETTING

University hospital.

PATIENTS

Thirty-five (35) ASA physical status I and II patients scheduled for elective surgery of the lower abdomen.

INTERVENTIONS

Patients were randomly divided into 2 groups to receive epidurally 8 mL of 0.2% or 1% ropivacaine followed by the same solution at a rate of 6 mL/h.

MEASUREMENTS

Twenty minutes after starting ropivacaine, a target-controlled infusion of propofol was started to provide a predicted blood concentration of 3 microg/mL; it increased by 0.5 microg/mL every 60 seconds until all 3 clinical end points were reached, as follows: P1, when patients lost consciousness; P2, when patients failed to show pupillary dilation and skin vasomotor reflex to transcutaneous electric stimulation applied to the upper level of loss of cold sensation; and P3, when patients failed to show pupillary dilation and skin vasomotor reflex to transcutaneous electric stimulation applied to C5.

MAIN RESULTS

The effective concentration 50 values for both predicted blood and effect-site propofol concentrations were significantly larger in the 0.2% group than in the 1% group at all end points. The BIS at every end point was significantly smaller in the 0.2% group than in the 1% group.

CONCLUSIONS

During combined epidural-propofol anesthesia, unconsciousness and lack of response to noxious stimulation occurred at lower predicted concentrations with 1% epidural ropivacaine than with 0.2% epidural ropivacaine. The results also suggest that the BIS may not be a good indicator when propofol anesthesia is combined with epidural anesthesia.