Intramuscular dexmedetomidine premedication—an alternative to midazolam-fentanyl-combination in elective hysterectomy?

Sedation, anxiolysis, intubation responses and fentanyl anaesthetic requirements were investigated in a double-blind, randomized study in twenty ASA I-II elective hysterectomy patients. Ten patients received dexmedetomidine 2.5 μg kg^-1 i.m. 60 min before induction and saline placebo i.v. 2 min prior to induction (= DP group). Ten patients received midazolam 0.08 mg kg^-1 i.m. 60 min and fentanyl 1.5 μg kg^-1 i.v. (= MF group) 2 min before induction of anaesthesia with thiopentone 4 mg kg^-1. Anaesthesia was maintained with 70% nitrous oxide in oxygen and with fentanyl 2 μg kg^-1 i.v. increments according to predetermined criteria. Both premedications induced sedation ( P < 0.01 in both groups) and anxiolysis ( P < 0.01 in DP vs <0.05 in MF group) without any differences between the groups. Haemodynamic changes following tracheal intubation did not significantly differ between the groups. Intraoperatively systolic and diastolic arterial pressure were 15% and 13% lower in DP group ( P < 0.01 and P < 0.05 for drug effect), the mean heart rate was approximately 9 beats min^-1 lower in DP group (n.s.). Fentanyl was required more often in MF group: median 3.5 (QD 1.5) vs. 2.5 (QD 0.5) times in DP group ( P < 0.05), the total amount being 57% smaller in DP group: 0.03 (QD 0.01) vs. 0.07 (QD 0.02) μg kg^-1 min^-1 ( P < 0.05). Postoperative course and analgesic requirements were similar in both groups. Dexmedetomidine premedication may offer an alternative to current anaesthesia practice in elective hysterectomy.     

ECG T-wave amplitude changes during thiopentone induction with or without alfentanil

The T-wave amplitude of ECG is thought to reflect the sympathetic tone of the heart but anaesthesia studies on this topic are rare. Haemodynamic and ECG T-wave amplitude changes were studied during induction of anaesthesia in 24 ASA I-II patients. Twelve patients were given alfentanil 30 μg kg^-1 at induction while physiologic saline was given to the rest (control). Thiopentone was then administered at the rate of 5 mg s^-1 until eyelash reflex disappeared. Vecuronium 0.1 mg kg^-1 was given thereafter. No anticholinergics were used. The lungs were ventilated with 40% oxygen in air. Haemodynamic parametres and T-wave amplitude were measured before induction, before intubation, 30 s, 3 min and 5 min after intubation. A significandy higher amount of thiopentone was needed to abolish the eyelash reflex in the control group than in the alfentanil group ( P <0.001). There were no changes in heart rate (HR) in the alfentanil group during the trial. Systolic and diastolic arterial pressures (SAP and DAP) were continuously below the preinduction levels in the alfentanil group. After baseline HR, SAP and DAP were significantly higher in the control group than in the alfentanil group at each data point. T-wave amplitude flattened significantly ( P <0.001) after intubation in the control group while no significant changes were seen in the alfentanil group. T-wave flattening correlated to the increases in HR ( P <0.01) and SAP ( P <0.01). Three control patients with flattened T-wave had a transient bigeminia period after intubation. It is concluded that ECG T-wave amplitude flattening was associated with pressure and heart rate response to laryngoscopy and intubation. Alfentanil blunted these responses and prevented T-wave changes after intubation.     

Sympathoadrenal activation and the dumping syndrome after gastric surgery

Dumping symptoms suggest concomitant sympathoadrenal activation. To evaluate the relation between dumping symptoms and postprandial plasma catecholamine changes, standardized dumping-provocation tests with use of oral glucose were performed for 16 gastric surgery patients with dumping, for 14 gastric surgery patients without dumping, and for 14 healthy control patients. Early dumping symptoms were present for all patients with dumping, and late symptoms developed in three patients with dumping after glucose ingestion. Patients without dumping and healthy control patients had slight complaints or no complains. Systolic and diastolic blood pressure remained unaffected for the three groups. Positive breath-hydrogen tests, heart rate increments, and reactive plasma glucose decrements were present for patients with dumping and for patients without dumping, but not for control patients. Plasma noradrenaline and adrenaline increased for patients with dumping and for patients without dumping, but not for control patients. The noradrenaline increment was higher for patients with dumping (98%) than for patients without dumping (78%; p<0.05). The noradrenaline increment was related to the dumping score and to the heart rate increment for the first hour after glucose ingestion, whereas the adrenaline increment was related to the plasma glucose decrement for the third hour. Therefore, dumping symptoms clearly are accompanied by postprandial sympathoadrenal activation, but sympathoadrenal activation cannot account completely for development of dumping symptoms.     

地塞米松氨茶碱及特布他林对家兔肾脏内髓集合管细胞H+/K+交换和Cl-/HCO3-交换的影响

目的：探讨地塞米松、氨茶碱及特布他林对肾脏内髓集合管（IMCD）细胞H^＋／K^＋交换和Cl^-／HCO3^-交换的影响。方法：根据分组情况，家兔肾脏IMCD细胞单层分别在2种浓度的地塞米松、氨茶碱或特布他林缓冲液中孵育72h，用荧光探针法测定各组的H^＋／K^＋交换及Cl^-／HCO3^-交换结果。结果：地塞米松、氨花碱和特布他林各组的H^＋／K^＋交换及Cl^-／HCO3^-交换与对照组相比，均无显著差异。结论：临床常用剂量的地塞米松、氨茶碱和特布他林对家兔肾脏IMCD细胞H^＋／K^＋交换及Cl^-／HCO3^-交换无显著影响。     

大鼠脑出血急性期延髓内脏带内胶质原纤维酸性蛋白表达的变化

观察脑出血急性期大鼠延髓内脏带 ( MVZ)内星形胶质细胞的反应。以尾壳核局部注射胶原酶制作脑出血模型 ,用抗星形胶质细胞特异性标识物胶质原纤维酸性蛋白 ( GFAP)的免疫细胞化学方法 ,研究脑出血后 MVZ内星形胶质细胞的变化。发现脑出血后 4h GFAP阳性细胞数量增多、胞体增大、突起伸长 ,在MVZ形成明显弧形带状分布 ,尤以 MVZ背内侧区、中间带及腹外侧区明显。提示 MVZ内星形胶质细胞可能参与了脑出血后的病理生理过程。     

Importance of pineal gland interactions with the sympathoadrenal system for the depressant action of reserpine

Reserpine lowered norepinephrine and dopamine levels in the hypothalamus of rats, particularly after pinealectomy. On the other hand, its effects on catecholamine levels in the adrenals of pinealectomized rats were weaker than in intact animals. It is suggested that the depression produced by reserpine may be due in part to impaired interactions of the pineal gland with central and peripheral components of the sympathoadrenal system. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, No. 6, pp. 651–653, June, 1996     

Q‐T interval (QTC) in patients with cirrhosis: relation to vasoactive peptides and heart rate

Objective. Prolonged Q‐T interval (QT) has been reported in patients with cirrhosis who also exhibit profound abnormalities in vasoactive peptides and often present with elevated heart rate (HR). The aim of this study was to relate QT to the circulating level of endothelins (ET‐1 and ET‐3) and calcitonin gene‐related peptide (CGRP) in patients with cirrhosis. In addition, we studied problems with HR correction of QT. Material and methods. Forty‐eight patients with cirrhosis and portal hypertension were studied during a haemodynamic investigation. Circulating levels of ETs and CGRP were determined by radioimmunoassays. Correction of QT for HR above 60 beats per min was performed using the methods described by Bazett (QT_C) and Fridericia (QT_F). Results. Prolonged QT_C (above 440?ms), found in 56?% of the patients, was related to the presence of significant portal hypertension and liver dysfunction (p<0.05 to 0.001), but not to elevated ET‐1, ET‐3 or CGRP. When corrected according to Bazett, QT_C showed no significant relation to differences in HR between patients (r = 0.07, ns). QT_F showed some undercorrection of HR (r = ?0.36; p<0.02). During HR variation in the individual patient, QT_C revealed a small but significant overcorrection (2.6?ms per heartbeat per min; p<0.001). This value was significantly (p<0.02) smaller with QT_F (1.2?ms per heartbeat per min). Conclusions. The prolonged QT_C in cirrhosis is related to liver dysfunction and the presence of portal hypertension, but not to the elevated powerful vasoconstrictor (ET‐1) or vasodilator (CGRP, ET‐3) peptides. The problems with correction of the QT for elevated HR in cirrhosis are complex, and the lowest HR should be applied for determination of the QT.     

Intracaval extension of pheochromocytoma simulating pulmonary embolism

Pheochromocytoma, a chromaffin tumor of the sympathoadrenal nervous system, rarely exhibits direct extension into the inferior vena cava. We report a patient with a right adrenal pheochromocytoma that caused symptoms of recurrent pulmonary emboli. Intracaval extension of the tumor was detected during investigations for the source of the emboli by abdominal CT scan, ultrasonography, and venacavography. The biochemical diagnosis of pheochromocytoma was confirmed by sharply elevated catecholamine, metanephrine, and VMA urinary levels, which returned to normal upon resection of the tumor. The patient had no evidence of metastatic disease.     

Cardiovascular and arousal responses to laryngoscopy and tracheal intubation in patients with complete spinal cord injury

Background: We aimed to determine whether the autonomic and arousal responsesto laryngoscopy and tracheal intubation were altered in patientswith spinal cord injury (SCI). Methods: One hundred and sixteen patients with traumatic complete SCIwere grouped according to the time elapsed after the injury(<3 days and >9 months) and the level of injury (aboveT5 and below T5): acute high (AH, n=25), chronic high (CH, n=26),acute low (AL, n=20), and chronic low (CL, n=45). Twenty-fivepatients without SCI served as a control group. Bispectral index(BIS) response, systolic arterial pressure (SAP), heart rate(HR), and plasma concentrations of catecholamines and argininevasopressin were measured. Results: Both CH and CL groups showed a greater reduction in BIS valuesafter induction of anaesthesia with thiopental compared withcontrols (P<0.05). However, BIS values after intubation increasedsimilarly in all groups from the value measured just beforelaryngoscopy. SAP increased in the AL and CL and control groupsbut not in the AH and CH groups. HR increased significantlyin all groups; though to a lesser degree in the AH comparedwith the other groups. Plasma norepinephrine concentrationsincreased in all except the AH group, but vasopressin concentrationswere unchanged. Conclusions: The arousal response to laryngoscopy and tracheal intubationas measured by BIS is not altered in SCI, but cardiovascularand catecholamine responses may be changed depending on timeelapsed and the level of the injury. However, an identical doseof thiopental may reduce BIS value after intubation more profoundlyin patients with chronic SCI.     

Sympathoadrenal system under conditions of increased left and right ventricular afterload

Adrenergic plexuses in the myocardium and adrenal medulla were studied histochemically under conditions of increased left or right ventricular afterload. Under conditions of high afterload not accompanied by heart failure the density of sympathetic myocardial innervation remained unchanged in the loaded ventricle, but increased in the intact ventricle. Comparison of the state of the sympathoadrenal system under conditions of increased afterload complicated or uncomplicated by heart failure revealed common prognostically unfavorable changes: sharp decrease in the density of adrenergic nerve plexuses in the ventricular myocardium and activation of adrenal chromaffin cells.Translated from Byulleten Eksperimentalnoi Biologii i Meditsiny, Vol. 138, No. 11, pp. 597–600, November, 2004