Effects of Head-up Tilt After Stellate Ganglion Block on QT Interval and QT Dispersion:

Effects on hemodynamic variables and echocardiographic parameters after a stellate ganglion block in 15 healthy volunteers

BACKGROUND

The sympathetic nervous system has an important role in generating pain. Various pathomechanisms are involved that respond well to the application of local anesthetics (LA), for example to the stellate ganglion block (SGB).

OBJECTIVES

We wanted to know more about the effects of SGB on cardiovascular parameters.

METHODS

We included 15 healthy volunteers; another 15 healthy volunteers as a control group (sham injection of LA). In order to produce a more precise SGB, we employed only a small volume of LA (3mL), a LA with a lower permeability (procaine 1%), and a modified injection technique. Systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), and echocardiographic parameters were recorded before and after SGB. We also investigated whether there are side differences (left and right SBG).

RESULTS

At baseline all parameters were within the normal range. After performing right and left SGB DBP significantly increased (on the right side from 68.73±8.61 to 73.53±11.10, p=0.015; on the left side from 70.66±13.01 to 77.93±10.40, p=0.003). In the control group no increase in DBP was observed. No side-specific differences were found, except a significant reduction in the maximum velocity of myocardial contraction during the systole with left-sided SGB.

CONCLUSIONS

Even with our methods we could not prevent the simultaneous occurrence of a partial parasympatholytic effect. For this reason, the SGB has only minor hemodynamic effects, which is desirable as it enhances the safety of the SGB.

Augmentation of cardiac sympathetic tone by percutaneous low-level stellate ganglion stimulation in humans: a feasibility study

Modulation of human cardiac mechanical and electrophysiologic function by direct stellate ganglion stimulation has not been performed. Our aim was to assess the effect of low-level left stellate ganglion (LSG) stimulation (SGS) on arrhythmias, hemodynamic, and cardiac electrophysiological indices. Patients undergoing ablation procedures for arrhythmias were recruited for SGS. A stimulating electrode was placed next to the LSG under fluoroscopy and ultrasound imaging; and SGS (5-10 Hz, 10-20 mA) was performed. We measured hemodynamic, intracardiac and ECG parameters, and activation recovery intervals (ARIs) (surrogate for action potential duration) from a duodecapolar catheter in the right ventricular outflow tract. Five patients underwent SGS (3 males, 45 ± 20 years). Stimulating catheter placement was successful, and without complication in all patients. SGS did not change heart rate, but increased mean arterial blood pressure (78 ± 3 mmHg to 98 ± 5 mmHg, P < 0.001) and dP/dt max (1148 ± 244 mmHg/sec to 1645 ± 493 mmHg/sec, P = 0.03). SGS shortened mean ARI from 304 ± 23 msec to 283 ± 17 msec (P < 0.001), although one patient required parasympathetic blockade. Dispersion of repolarization (DOR) increased in four patients and decreased in one, consistent with animal models. QT interval, T-wave duration and amplitude at baseline and with SGS were 415 ± 15 msec versus 399 ± 15 msec (P < 0.001); 201 ± 12 msec versus 230 ± 28 msec; and 0.2 ± 0.09 mV versus 0.22 ± 0.08 mV, respectively. At the level of SGS performed, no increase in arrhythmias was seen. Percutaneous low-level SGS shortens ARI in the RVOT, and increases blood pressure and LV contractility. These observations demonstrate feasibility of percutaneous SGS in humans.

Continuous administration of landiolol reduced QT dispersion in postoperative patients

STUDY OBJECTIVE

To determine the changes in QT dispersion (QTD) in the standard electrocardiogram (ECG) of postoperative patients and the effect of landiolol on QTD.

DESIGN

Randomized, prospective, double-blinded study.

PATIENTS

40 postsurgical patients.

INVENTIONS

Patients were allocated to three groups: Control group patients (Group C) were administered saline and patients in the landiolol groups (Group L2 and Group L5) were infused landiolol 2 μg/kg/min and 5 μg/kg/min, respectively. All infusions were started at midnight and discontinued at 6 o'clock in the morning.

MEASUREMENTS

Heart rate (HR), systolic (SBP) and diastolic (DBP) invasive blood pressure, and ECG were recorded at 0 (immediately before infusion), at 3 o'clock, and 6 o'clock (immediately before termination). The ECG wave was recorded electronically and QTD was analyzed using PC software. Heart rate, blood pressure, QT interval, and QTD were compared as changes from baseline values.

MAIN RESULTS

In Groups L2 and L5, HR was significantly decreased, approximately 10 bpm. Both SBP and DBP showed a decreasing trend at 3 o'clock. Absolute QT interval was prolonged in all groups; however, the decrease in QTD occurred in Group L5.

CONCLUSIONS

Continuous administration of landiolol prevents the increase in QTD found on the morning in postoperative patients. Landiolol demonstrated a possible antiarrhythmic effect by improving the imbalance of repolarization.

Hypotensive bradycardic events during shoulder arthroscopic surgery under interscalene brachial plexus blocks

Sudden, profound hypotensive and bradycardic events (HBEs) have been reported in more than 20% of patients undergoing shoulder arthroscopy in the sitting position. Although HBEs may be associated with the adverse effects of interscalene brachial plexus block (ISBPB) in the sitting position, the underlying mechanisms responsible for HBEs during the course of shoulder surgery are not well understood. The basic mechanisms of HBEs may be associated with the underlying mechanisms responsible for vasovagal syncope, carotid sinus hypersensitivity or orthostatic syncope. In this review, we discussed the possible mechanisms of HBEs during shoulder arthroscopic surgery, in the sitting position, under ISBPB. In particular, we focused on the relationship between HBEs and various types of syncopal reactions, the relationship between HBEs and the Bezold-Jarisch reflex, and the new contributing factors for the occurrence of HBEs, such as stellate ganglion block or the intraoperative administration of intravenous fentanyl.

QTc interval and neurological outcomes in aneurysmal subarachnoid hemorrhage

BACKGROUND

Prolonged heart rate-corrected QT (QTc) interval is frequently observed in subarachnoid hemorrhage (SAH). This study was conducted to determine the relationship between QTc interval and neurological outcome during the acute posthemorrhagic period after aneurysmal SAH.

METHODS

We studied 71 patients undergoing surgery who were admitted within 24 h after the onset of aneurysmal SAH. Standard 12-lead electrocardiography was performed on admission (T1) and at 1 and 7 days after operation (T2 and T3). QT intervals were corrected by heart rate according to the Fridericia formula. The Glasgow Coma Scale (GCS) score was calculated over the period T1-T3. Neurological outcome was assessed using the Glasgow Outcome Scale at hospital discharge.

RESULTS

Among the 71 patients, 31 had an unfavorable neurological outcome. Although QTc interval prolongation improved in patients with a good outcome, QTc interval prolongation continued in patients with an unfavorable outcome. The areas under the receiver-operator characteristic curves showed that the QTc and GCS score at T3, and the Hunt and Hess grade were significant predictors of an unfavorable neurological outcome. The threshold value, sensitivity, and specificity for the QTc at T3 were 448 ms, 73% [95% confidence interval (CI), 68-78], and 93% (95% CI, 90-96), respectively.

CONCLUSION

This study confirms that QTc interval prolongation continues in the SAH patients with an unfavorable outcome but that QTc interval prolongation improves in patients with a good outcome, suggesting that a QTc interval of more than 448 ms at 7 days after operation is a predictor of neurological outcome after SAH.

A comparison of the effect on QT interval between thiamylal and propofol during anaesthetic induction*

SUMMARY

The aim of this study was to determine the effect of thiamylal and propofol on heart rate-corrected QT (QTc) interval during anaesthetic induction. We studied 50 patients undergoing lumbar spine surgery. Patients were administered 3 microgxkg(-1) fentanyl and were randomly allocated to receive 5 mgxkg(-1) thiamylal or 1.5 mgxkg(-1) propofol as an induction agent. Tracheal intubation was performed after vecuronium administration. Heart rate, mean arterial pressure, bispectral index score, and 12-lead electrocardiogram were recorded at the following time points: just before (T1) and 2 min after (T2) fentanyl administration; 2 min after anaesthetic administration (T3); 2.5 min after vecuronium injection (T4); and 2 min after intubation (T5). Thiamylal prolonged (p < 0.0001), but propofol shortened (p < 0.0001), the QTc interval.

Factors contributing to episodes of bradycardia hypotension during shoulder arthroscopic surgery in the sitting position after interscalene block

Background

Arthroscopic shoulder surgery has been performed in the sitting position under interscalene block (ISB). Bradycardia hypotension (BH) episodes have a reported incidence of 13-29% in this setting. We performed a retrospective study to investigate contributing factors to the occurrence of BH episodes.

Methods

According to BH episodes, we divided 63 patients into two groups: BH group (n = 13) and non-BH group (n = 50). Anesthetic records and block data sheets were reviewed for demographic data, intraoperative medications, sites of ISB, use of epinephrine in local anesthetics, degree of sensory blockade, and percent change of heart rate or systolic blood pressure (SBP). Statistical analysis was done using Chi square test and Student's t-test.

Results

There were no significant differences in the use of epinephrine in local anesthetics between the two groups. The location of ISB site was different between the two groups in that there were relatively more right-sided ISBs in the BH group than in the non-BH group (P = 0.048). The degree of sensory blockade was lower, but not significantly, in the C8 and T1 dermatomes of the BH group than in the non-BH group (P = 0.060 and 0.077, respectively). There was a relatively higher incidence of fentanyl supplementation in the BH group than in the non-BH group (P = 0.000).

Conclusions

These results suggest that right ISB and perioperative supplementation of fentanyl due to incomplete block are possible contributing factors to the occurrence of BH episodes in the sitting position during shoulder surgery using ISB.