Intracranial pressure changes during bilateral radical neck dissections

The management of the contralateral neck in patients with head and neck cancer who have undergone a radical neck dissection (RND) is controversial. A number of these patients will require a second RND. Sacrifice of both internal jugular veins (IJV) has been felt to lead to increased intracranial pressure (ICP) with subsequent neurologic sequelae. From 1987 to 1991 four patients had staged bilateral RNDs at the West Virginia University. In these patients a subarachnoid bolt was placed to directly monitor ICP. Jugular bulb, mean arterial, pulmonary artery, and central venous pressures were monitored. Electroencephalographic (EEG) monitoring was also performed. All patients demonstrated elevations in ICP immediately on head rotation. Further marked elevations were noted immediately after IJV ligation with a maximum peak at 30 minutes. Pressure levels of greater than 40 mm Hg were observed in three of four patients. Systemic hypertension was observed in response to elevated ICP (Cushing's reflex). All patients studied recovered from surgery without significant sequelae. Within 24 hours the ICP had returned to normal in all patients. Three patients required intraoperative intervention to lower their ICP. We demonstrate that even in a staged second RND there are significant rises in ICP. These are to a level that suggests emergency medical intervention is required. We feel that when the second IJV is sacrificed an increase in ICP should be anticipated, monitored, and treated accordingly.     

Long QT interval syndrome with increased QT dispersion

This case report describes the anaesthetic management of a patient with sporadic-type long QT interval syndrome (LQTS), and increased QT dispersion, who presented for removal of an ovarian cyst. Beta adrenergic blockade and adequate depth of anaesthesia for successful management is emphasized. The Successful use of epidural administration of lignocaine and opioids in addition to general anaesthesia is described.     

Value of contralateral supraomohyoid neck dissections

This study was carried out to determine the merit of contralateral supraomohyoid neck dissection in the clinically negative neck. When performed in conjunction with a standard radical neck dissection on the ipsilateral side, a yield of 2.8 percent pathologically positive nodes (5 of 177) was obtained in the contralateral neck. Little difference was noted in the yield of midline lesions versus unilateral lesions which approached the midline (3 and 2.6 percent, respectively). Similarly, the yield with preoperative radiation was close to that of the nonradiated group (3 and 2.7 percent, respectively). Additionally, in 1.7 percent of patients (3 of 177) with both clinically and pathologically negative nodes, metastases later developed in the contralateral neck, which indicates that the dissection is not necessarily effective in preventing future disease. The contralateral supraomohyoid neck dissection in the treatment of malignancies of the oral cavity, pharynx, and larynx does not appear to be of significant therapeutic value.     

Shoulder function after accessory nerve-sparing neck dissections

BACKGROUND: This study was designed to observe the effect of preserving the spinal accessory nerve (SAN) during neck dissection (ND) and adjuvant radiotherapy (ART) after ND on shoulder function. METHODS: Fifty-seven patients with head and neck cancer who had undergone primary tumor resection and various types of NDs were enrolled in this prospective study. Postoperative shoulder joint range of motion was evaluated by goniometry, and muscle strength was measured manually. SAN function was evaluated with electromyography (EMG) with respect to percentage of denervation and presence of neurogenic involvement. Patients were grouped by treatment as follows: radical ND (RND) versus modified radical ND (MRND)/selective ND (SND) and ART versus no ART. RESULTS: Shoulder joint range of motion and shoulder muscle strength were significantly better in the MRND/SND group than in the RND group. However, EMG findings were similar in the RND and MRND/SND groups. When all patients who underwent ND, RND, or MRND/SND were compared with the control group, statistically significant changes in shoulder joint range of motion and shoulder muscle strength were found. Also, denervation and neurogenic involvement of the SAN were significantly higher after all NDs than in the control group. ART did not affect range of motion of the shoulder joint, shoulder muscle strength, or the degree of denervation and neurogenic involvement in any of the ND groups. CONCLUSIONS: ART does not have a negative effect on shoulder function after ND. SAN is always functionally impaired even if we preserve it macroscopically during ND.     

QT interval dispersion in dialysis patients

The leading cause of mortality in dialysis patients is cardiovascular complications, including ventricular arrhythmias and sudden cardiac death. A reliable non-invasive predictive test of sudden death is therefore important. The interlead variation in duration of the QT interval on the surface electrocardiogram corrected with heart rate (QTc dispersion) might serve as a surrogate for ventricular arrhythmia. Prolonged QTc dispersion is commonly encountered in dialysis patients and possesses an increased risk of all mortality, including cardiovascular mortality. QT dispersion might be affected by shifts of the intracellular electrolytes during dialysis and increasing deposition of iron in cardiac muscles in these patients who have underlying heart diseases. Although no well-designed study has been done, the factors contributing to prolongation of QTc dispersion should be avoided. We summarize the results of the currently available clinical studies that examined QTc dispersion in dialysis patients.     

Acquired long QT syndrome and elective anesthesia in children

We present the case of a child who had had a previous episode of torsades de pointes (TdP) and who was scheduled for elective surgery under general anesthesia. The pathophysiology of this condition and the anesthesia concerns are discussed. An 8-year-old male with a history of osteogenic sarcoma had undergone an uneventful limb salvage procedure 2 years earlier. During a subsequent admission to the hospital, he had had a cardiopulmonary arrest with complete recovery. Telemetry electrocardiogram (ECG) rhythm recordings obtained during the event showed TdP that degenerated into ventricular fibrillation, which then terminated spontaneously. On a subsequent ECG, the QTc interval was 694 ms. The prolonged QT interval was attributed to homeopathic use of cesium chloride supplements and the QT interval normalized after cesium was stopped. He presented for an elective procedure and, with an anesthetic plan that emphasized medications without known effect on the QT interval, had an uneventful perioperative course. The optimal anesthesia plan for patients with prolonged QT or those suspected to be at risk for prolongation of the QT interval has not been well described. Available evidence suggests that using total intravenous anesthesia with propofol may be the safest and was used uneventfully in this case. Additionally, this case emphasizes the need to inquire about the use of supplements and naturopathic medications, even in children, that may have life-threatening side effects or interactions with anesthetic agents.     

QT interval measurement: evaluation of automatic QTc measurement and new simple method to calculate and interpret corrected QT interval

BACKGROUND: Assessment of repolarization duration is often recommended to avoid administration of QT-prolonging drugs in patients with prolonged QTc interval, a frequent situation in the postoperative period. Bazett QT correction inappropriately increases QTc when heart rate is increased, and the use of the Fridericia formula may avoid a falsely prolonged QTc interval. The authors assessed automatic QT interval measurement to detect prolonged QTc interval (women >450 ms; men >440 ms) in the postoperative setting. METHODS: Automatic and manual electrocardiograms were performed in 108 patients after anesthesia. Automatic electrocardiographic measurement used the Bazett formula. Manual measurements were made from each electrocardiogram and used as the reference. Agreement between the two methods was analyzed. Bazett and Fridericia QT corrections were compared in this population. RESULTS: Agreement between automatic and manual measurements was low. The Fridericia correction, but not the Bazett correction, was independent from heart rate and allowed adequate QT correction. Sensitivity of automatic measurements to detect prolonged QTc-Bazett interval was 54%. Automatic QTc-Bazett interval less than 430 ms ruled out a manual prolonged QTc interval. When automatic QTc-Bazett was greater than 430 ms, this value was converted according to Fridericia. Automatic QTc-Fridericia greater than 430 ms identified all patients with prolonged manual QTc with a negative predictive error of 0% (95% confidence interval, 0-7%). QTc-Fridericia can be approximated by respectively adding or subtracting 5% to the uncorrected QT for each increase or decrease by 10 beats/min in heart rate from 60 beats/min. CONCLUSIONS: Automatic QTc-Bazett measurement, if abnormal, associated with calculation of QTc-Fridericia reliably identifies patients in whom manual QTc measurement must be performed to confirm postoperative prolonged QTc interval.     

The QT interval following carotid artery resection

Background. Right radical neck dissection has been shown to prolong the QT interval, reportedly caused by surgical trauma to the cervical autonomic system, which may result in malignant ventricular arrhythmias. Carotid artery resection would be expected to be more likely to cause dangerous arrhythmias. Methods. We prospectively studied eight patients with electrocardiograms before and after carotid resection. Four patients had left-sided procedures and four patients had right-sided procedures. In addition, 11 patients were studied retrospectively. QT intervals were normal in all patients preoperatively. Results. Preoperative corrected QT intervals (QTc) were in the normal range used by our institution for all eight patients in the prospective group. There were no significant QTc changes after either left-sided or right-sided carotid resection. However, the retrospective group did show significant changes in QTc following right carotid resection (n = 5), but not left resection (n = 6). Conclusions. EKG changes associated with carotid resection may not be uniform and may depend on surgical technique or specific anatomic factors. Controlled prospective studies are needed to confirm the prevalence of QT interval changes in radical neck surgery.     

Anesthetic implications of prolonged QT interval syndromes

The prolonged QT interval syndromes consist of two forms, one congenital and one acquired. The congenital form is probably due to an imbalance in the sympathetic nervous system supply to the heart. It is a preventable cause of sudden death both at an early age and during anesthesia. Recognition of congenital forms of prolonged QT interval and treatment with beta-adrenergic blockers have reduced the mortality. Special care in the perioperative period is necessary to prevent anesthetic-related deaths. The acquired form has many causes. These may be present preoperatively or they may occur intraoperatively. It is important that patients with ALQTS are recognized early and the underlying cause treated.     

Assessment of QT interval and QT dispersion following stellate ganglion block using computerized measurements

BACKGROUND AND OBJECTIVES: Prolongation of QT interval and QT dispersion (QTD) may be associated with an increased risk of arrhythmias. This study was designed to investigate the effects of right or left stellate ganglion block (SGB) on RR interval, QT interval, the rate-corrected QT (QTc) interval, QTD and the rate-corrected QTD (QTcD) using computerized measurements. METHODS: Ten healthy volunteers underwent both right and left SGBs using 7 mL 1% mepivacaine with a 7-day interval between the 2 blocks. The measurement from the 12-lead electrocardiogram was performed for 60 minutes after SGB. RESULTS: Right SGB induced a significant decrease of RR interval immediately after the block, and significant increases of QT interval, QTc interval, QTD, and QTcD from immediately through 50 minutes after the block (P <.01). Left SGB induced a significant decrease of RR interval, and significant increases of QTc interval and QTD immediately after the block (P <.01). Left SGB also produced a significant decrease of QT interval from 20 through 50 minutes after the block, and a significant decrease of QTc interval from 30 through 50 minutes after the block (P <.05). CONCLUSIONS: Right SGB induces increases of the QT interval, QTc interval, QTD, and QTcD, and left SGB induces decreases of the QT interval and QTc interval.