Propofol prevents lipid peroxidation following transient forebrain ischemia in gerbils

PURPOSE

To ascertain whether propofol prevents lipid peroxidation on delayed neuronal death induced by transient forebrain ischemia in the hippocampal CA1 subfield in gerbils.

METHODS

Forty gerbils were randomly assigned to five groups: Group I, control, sham operation treated with physiological saline solution (PSS); Group II, ischemia/reperfusion treated with PSS; Group III, ischemia/reperfusion treated with 50 mg x kg(-1) propofol; Group IV, ischemia/reperfusion treated with 100 mg x kg(-1) propofol; Group V, ischemia/reperfusion treated with 150 mg x kg(-1) propofol. Transient forebrain ischemia was induced by occluding the bilateral common carotid arteries for four minutes under N2O/O2/halothane anesthesia after propofol or PSS. Five days later, the cerebrum was removed and each forebrain was cut into two including the hippocampus. Lipid peroxidation was determined using the production of malondialdehyde (MDA), and histopathological changes in the hippocampal CA1 subfield were examined.

RESULTS

In group II, the pyramidal cells were atrophic and pycnotic; vacuolation and structural disruption of the radial striated zone was observed. In the other four groups, these changes were not observed. Degenerative ratios of pyramidal cells were: Group I: 4.9 +/- 2.3, Group II: 94.1 +/- 4.5 (P < 0.01), Group III: 12.5 +/- 5.7, Group IV: 11.0 +/- 4.6, Group V: 9.6 +/- 4.9%. Production of MDA was: Group I: 83 +/- 22, Group II: 198 +/- 25 (P < 0.01), Group III: 153 +/- 39, Group IV: 113 +/- 34, Group V: 106 +/- 27 nmol x g(-1) wet tissue.

CONCLUSION

Propofol attenuated delayed neuronal death by preventing lipid peroxidation induced by transient forebrain ischemia in the hippocampal CA1 subfield in gerbils.

Comparison Between Intraperitoneal CO2 Insufflation and Abdominal Wall Lift on QT Dispersion and Rate-corrected QT Dispersion During Laparoscopic Cholecystectomy

This study compared the effect of intraperitoneal CO2 insufflation with abdominal wall lift on RR interval, QT interval, the rate-corrected QT (QTc) interval, QT dispersion (QTD), and the rate-corrected QTD (QTcD) using computerized measurement during laparoscopic cholecystectomy. Thirty patients scheduled for laparoscopic cholecystectomy were randomly assigned to 2 groups: intraperitoneal CO2 insufflation (CO2 group) or abdominal wall lift (lift group). A 12-lead electrocardiogram was monitored to measure parameters. The RR interval, QT interval, and QTc interval did not change significantly during the study in both groups. The QTD and QTcD in the CO2 group increased significantly during CO2 insufflation, and were significantly higher than those of the lift group. Statistically significant increases of QTD and QTcD, which are associated with an increased risk of arrhythmias and cardiac events, occur during CO2 insufflation, and QTD and QTcD in the CO2 group were significantly higher than those of the lift group.

Superoxide radical generation and histopathological changes in hippocampal CA1 after ischaemia/reperfusion in gerbils

PURPOSE

We investigated the relationship between the generation of superoxide radicals and histopathological changes on delayed neuronal death in the hippocampal CA1 subfield.

METHODS

Seventy gerbils were randomly assigned to two groups, a sham group and an ischaemia/reperfusion (I/R) group. In the I/R group, transient forebrain ischaemia was induced by occluding the bilateral common carotid arteries for four minutes. The cerebrum was removed after reperfusion at intervals of one minute, six, twelve and twenty-four hr and at three, five and seven days. Each forebrain was cut into two portions including the hippocampus. The quantity of superoxide radicals was measured by using chemiluminescence, and histopathological changes in the hippocampal CA1 subfield were examined.

RESULTS

In the I/R group, superoxide radicals increased on the 3rd and 5th days compared with the sham group (16.1 +/- 3.4 vs 3.2 +/- 1.0 on the third day (P < 0.0001); 10.9 +/- 1.9 vs 3.3 +/- 0.8 on the fifth day (P < 0.0001)). In the I/R group, the pyramidal cells were atrophic and pycnotic; vacuolation, and structural disruption of the radial striated zone were observed from the third through the seventh day. In the sham group, these changes were not observed. There were differences of degenerative ratios in the pyramidal cells between the two groups from the third to seventh days (5.6 +/- 2.0 vs 80.9 +/- 3.3 on the third day (P < 0.05); 6.9 +/- 0.4 vs 93.6 +/- 2.4 on the fifth day (P < 0.05); 6.2 +/- 1.5 vs 95.0 +/- 1.3 on the seventh day (P < 0.05)).

CONCLUSION

There is a correlation between the generation of superoxide radicals and histopathological changes of the pyramidal cells in the hippocampal CA1 subfield.

Three Types of A11 Neurons Project to the Rat Spinal Cord

The A11 dopaminergic cell group is the only group among the A8-A16 dopaminergic cell groups that includes neurons innervating the spinal cord, and a decrease in dopaminergic transmission at the spinal cord is thought to contribute to the pathogenesis of restless legs syndrome. However, the mechanisms regulating the neuronal activity of A11 dopaminergic neurons remain to be elucidated. Unraveling the neuronal composition, distribution and connectivity of A11 neurons would provide insights into the mechanisms regulating the spinal dopaminergic system. To address this, we performed immunohistochemistry for calcium-binding proteins such as calbindin (Calb) and parvalbumin (PV), in combination with the retrograde tracer Fluorogold (FG) injected into the spinal cord. Immunohistochemistry for Calb, PV, or tyrosine hydroxylase (TH), a marker for dopaminergic neurons, revealed that there were at least three types of neurons in the A11 region: neurons expressing Calb, TH, or both TH and Calb, whereas there were no PV-immunoreactive (IR) cell bodies. Both Calb- and PV-IR processes were found throughout the entire A11 region, extending in varied directions depending on the level relative to bregma. We found retrogradely labeled FG-positive neurons expressing TH, Calb, or both TH and Calb, as well as FG-positive neurons lacking both TH and Calb. These findings indicate that the A11 region is composed of a variety of neurons that are distinct in their neurochemical properties, and suggest that the diencephalospinal dopamine system may be regulated at the A11region by both Calb-IR and PV-IR processes, and at the terminal region of the spinal cord by Calb-IR processes derived from the A11 region.

Assessment of QT interval and QT dispersion during electroconvulsive therapy using computerized measurements

BACKGROUND

Electroconvulsive therapy (ECT) used in the treatment of severe psychiatric disorders induces stimulation of the autonomic nervous system with initial parasympathetic outflow immediately followed by a sympathetic response. These responses induce an initial bradycardia, arrhythmias, and hypertension. QT dispersion (QTD), defined as maximal QT interval minus minimal QT interval on 12 leads of the surface electrocardiogram, reflects regional heterogeneity of ventricular repolarization. The effects of electrical stimulus due to ECT on QT interval and QTD are of considerable interest.

OBJECTIVE

: This study was designed to investigate the effects of electrical stimulation caused by ECT on RR interval, QT interval, the rate-corrected QT (QTc) interval, QTD, and the rate-corrected QTD (QTcD) under general anesthesia using computerized measurements.

METHODS

Thirty psychiatric patients scheduled for ECT were studied under propofol anesthesia. A 12-lead electrocardiogram was monitored to measure parameters. Muscle paralysis was achieved by administering succinylcholine 1 mg/kg intravenously, and the efficacy of ECT was determined by the tourniquet technique.

RESULTS

The RR interval and QT interval decreased significantly immediately after electrical stimulus, and returned to the baseline level 1 minute after electrical stimulus. In 25 out of 30 patients, the baseline value of QTc interval was higher than the normal limits, and the QTc interval decreased significantly for 2 minutes after electrical stimulus. In 27 out of 30 patients, the baseline values of QTD and QTcD were higher than the normal limits, and the QTD and QTcD increased significantly from immediately after electrical stimulus to 5 minutes after electrical stimulus.

CONCLUSIONS

The QTc interval, QTD, and QTcD, which were associated with increased risks of ventricular arrhythmias, increased significantly before anesthetic induction in patients with major depression. Electrical stimulus during ECT induced further increases of the QTD and QTcD.

A combination of heparin and an intermittent pneumatic compression device may be more effective to prevent deep-vein thrombosis in the lower extremities after laparoscopic cholecystectomy

BACKGROUND

The purpose of this study was to clarify the effect of a combination of heparin and an intermittent pneumatic compression device on thrombogenesis and platelet activation in the upper and lower extremities after laparoscopy.

METHODS

A blinded study was performed on 30 patients. Patients were randomly injected with either heparin or physiological saline solution (PSS) subcutaneously. The intermittent compression boot was used during surgery. Plasma D-dimer (D-D), a marker of thrombogenesis, and b-thromboglobulin (b-TG), a marker of platelet activation, were measured in the upper and lower extremities.

RESULTS

In the heparin group, D-Ds in the upper and lower extremities increased significantly 24 h after surgery, but they were significantly lower than those of the PSS group. b-TG in the lower extremities of patients in the PSS group increased significantly 24 h after surgery.

CONCLUSION

A combination of low-molecular-weight heparin and intermittent pneumatic compression may be more effective to prevent deep-vein thrombosis in the legs.

The Japanese Epidemiologic Study for Perioperative Anaphylaxis, a prospective nationwide study: clinical signs, severity, and therapeutic agents

BACKGROUND

Diagnosis of perioperative anaphylaxis is difficult because of its non-specific and variable signs and symptoms. Therapeutic agents used to treat anaphylaxis and anaesthesiologist responses also vary depending on the case, which might affect outcomes; however, only a few studies have focused on these factors.

METHODS

This prospective study of perioperative anaphylaxis, a part of the Japanese Epidemiologic Study for Perioperative Anaphylaxis, investigated the clinical signs, its severity, therapeutic drugs, epinephrine administration, and anaesthesiologist responses in cases of perioperative anaphylaxis to assess trends and variability. Shock index was used to assess severity of cardiovascular collapse.

RESULTS

In 43 patients analysed in this study, cardiovascular signs (88.4%) were the most frequent, followed by skin (81.4%) and respiratory signs (60.5%). The presence of signs increased during the clinical course. The median time from the first signs to diagnosis of anaphylaxis was 10 (5.0-17.8) min. The rates of epinephrine use were 30.2% (unused), 48.8% (i.v.), and 20.9% (i.m.). The median time from diagnosis of anaphylaxis to epinephrine administration was 7 (inter-quartile range: 1.5-8.0) min. Antihistamines and corticosteroids were each used in 69.8% of cases. The worst shock index was higher in patients who received i.v. epinephrine (2.77 [0.90] mean [standard deviation]) than in both no epinephrine use cases (1.35 [0.41]) and i.m. epinephrine cases (1.89 [0.77] (P<0.001]).

CONCLUSIONS

The clinical signs and treatments of perioperative anaphylaxis are variable, and the choice regarding epinephrine administration is based on symptom severity.

CLINICAL TRIAL REGISTRATION

UMIN000035350.

QT interval and QT dispersion increase in the elderly during laparoscopic cholecystectomy: a preliminary study

PURPOSE

To compare the influence of a longer duration of intraperitoneal CO2 insufflation with head-up tilt on electrocardiogram indices during laparoscopic cholecystectomy between elderly and younger patients.

METHODS

Twelve elderly and 12 younger patients were studied. In all patients, intraperitoneal CO2 insufflation was performed for more than 150 min in the head-up position. RR interval, QT interval, the rate-corrected QT (QTc) interval, QT dispersion (QTD) and the rate-corrected QTD (QTcD) were measured.

RESULTS

The QT interval and the QTc interval increased significantly from 120 to 150 min after CO2 insufflation in the elderly. The QTD and QTcD increased significantly during CO2 insufflation in both groups. Those were significantly greater in the elderly than in younger patients from 120 to 150 min after CO2 insufflation.

CONCLUSION

Longer duration of CO2 insufflation with head-up tilt is associated with a prolongation of the QT interval and the QTD in elderly patients. The clinical significance of these findings remains to be determined.

Effects of general anesthetics on substance P release and c-Fos expression in the spinal dorsal horn

BACKGROUND

The authors examined in vivo the effects of general anesthetics on evoked substance P release (primary afferent excitability) and c-Fos expression (neuronal activation) in superficial dorsal horn.

METHODS

Rats received saline, propofol (100 mg/kg), pentobarbital (50 mg/kg), isoflurane (2 minimum alveolar concentration), nitrous oxide (66%), or fentanyl (30 μg/kg). During anesthesia, rats received intraplantar 5% formalin (50 μl) to left hind paw. Ten minutes later, rats underwent transcardial perfusion with 4% paraformaldehyde. Substance P release from small primary afferents was assessed by incidence of neurokinin 1 receptor internalization in the superficial dorsal horn. In separate studies, rats were sacrificed after 2 h and c-Fos expression measured.

RESULTS

Intraplantar formalin-induced robust neurokinin 1 receptor internalization in ipsilateral dorsal horn (ipsilateral: 54 ± 6% [mean ± SEM], contralateral: 12 ± 2%; P < 0.05; n = 4). Fentanyl, but not propofol, pentobarbital, isoflurane, nor nitrous oxide alone inhibited neurokinin 1 receptor internalization. However, 2 minimum alveolar concentration isoflurane + nitrous oxide reduced neurokinin 1 receptor internalization (27 ± 3%; P < 0.05; n = 5). All agents reduced c-Fos expression (control: 34 ± 4, fentanyl: 8 ± 2, isoflurane: 12 ± 3, nitrous oxide: 11 ± 2, isoflurane + nitrous oxide: 12 ± 1, pentobarbital: 11 ± 2, propofol: 13 ± 3; P < 0.05; n = 3).

CONCLUSION

General anesthetics at anesthetic concentrations block spinal neuron activation through a mechanism that is independent of an effect on small primary afferent peptide release. The effect of fentanyl alone and the synergistic effect of isoflurane and nitrous oxide on substance P release suggest a correlative rationale for the therapeutic use of these anesthetic protocols by blocking nociceptive afferent transmitter release and preventing the initiation of cascade, which is immediately postsynaptic to the primary afferent.

Effects of head-up tilt after stellate ganglion block on QT interval and QT dispersion

BACKGROUND AND OBJECTIVES

The aim of this study is to examine the effects of head-up tilt (70 degrees ) 30 minutes after right or left stellate ganglion block (SGB) on RR interval, QT interval, the rate-corrected QT (QTc) interval, QT dispersion (QTD), and the rate-corrected QT dispersion (QTcD) using computerized measurement.

METHODS

Ten healthy volunteers underwent both right and left SGBs using 7 mL 1% mepivacaine with a 7-day interval between the two blocks. A 12-lead electrocardiogram was monitored to measure parameters before SGB; 30 minutes after SGB (before head-up tilt); and immediately, 5, 10, and 15 minutes after head-up tilt.

RESULTS

Right SGB induced significant increases in QT interval, QTc interval, QTD, and QTcD from 30 minutes after the block through 15 minutes after head-up tilt. There were significant increases of QT interval, QTc interval, and QTcD between before and immediately after head-up tilt in right SGB. Left SGB induced significant decreases of QT interval and QTc interval from 30 minutes after SGB through 15 minutes after head-up tilt. Left SGB also induced a significant decrease of QTD from immediately after through 10 minutes after head-up tilt.

CONCLUSIONS

Significant increases of QT interval, QTc interval, and QTcD, which are associated with an increased risk of ventricular arrhythmias and cardiac events, occur immediately after head-up tilt in right SGB. However, head-up tilt does not induce increases of QT interval, QTc interval, QTD, and QTcD in left SGB.

Does hypertonic saline have preventive effects against delayed neuronal death in gerbil hippocampus?

This experiment was conducted to ascertain whether or not hypertonic saline solution (HSS) has preventive effects on delayed neuronal death in the hippocampal CA1 subfield of the gerbil. Twenty-eight gerbils were anesthetized with 1% halothane and 50% nitrous oxide during the experimental period. Their common carotid arteries were occluded bilaterally for 2.5 min, immediately after which 2 mL/kg of 10% NaCl was infused via the tail vein. Two mL/kg of physiological saline solution (PSS) was used for the control group in the same manner. 5 days later, after the cerebrum was removed, the hippocampus was stained with hematoxylin-eosin, and histopathological changes in the CA1 subfield were observed under the light microscope. Degenerative or necrotic pyramidal cells were compared among groups. The degeneration rates of the pyramidal cells were as follows; after sham operation with PSS, 4.2 +/- 1.8%; after sham operation with HSS, 6.5 +/- 3.3%; on ischemia-reperfusion with PSS, 95.6 +/- 1.6%; on ischemia-reperfusion with HSS, 7.1 +/- 3.0%. This study suggested that hypertonic saline might prevent delayed neuronal death in the hippocampal CA1 subfield of gerbils subjected to cerebral ischemia-reperfusion.

Calbindin-Positive Neurons Co-express Functional Markers in a Location-Dependent Manner Within the A11 Region of the Rat Brain

The A11 region plays a role in numerous physiological functions, including pain and locomotor activity, and consists of a variety of neurons including GABAergic, calbindin positive (Calb+), and dopaminergic (DA) neurons. However, the neurochemical nature of Calb+ neurons and their regulatory role in the A11 region remain largely unknown. In this study, we examined the kind of functional markers co-expressed in the Calb+ neurons using sections from 8-week-old rats. To examine a marker related to classical neurotransmitters, we performed in situ hybridization for vesicular glutamate transporter 2 (vGluT2) or glutamate decarboxylase (GAD) 65 and 67, in conjunction with Calb immunohistochemistry. We found cellular co-expression of Calb with vGluT2 or GAD65/67 throughout the A11 region. Nearly all Calb+/GAD65/67+ neurons were found in the rostral-middle aspect of the A11 region. In contrast, Calb+/vGluT2+ neurons were found predominantly in the middle-caudal aspect of the A11 region. For receptors and neuropeptides, we performed immunohistochemistry for androgen receptor (AR), estrogen receptors (ERα and ERβ), and calcitonin gene-related peptide (CGRP). We found that Calb+ neurons co-expressed AR in the rostral aspect of the A11 region in both male and female rats. However, we rarely find cellular co-expression of Calb with ERα or ERβ in this region. For CGRP, we found both Calb+ neurons with or without CGRP expression. These results demonstrate that Calb+ neurons co-express many functional markers. Calb+ neurons have a distinct distribution pattern and may play a variety of regulatory roles, depending on their location within the A11 region.

Comparison of bupivacaine, ropivacaine, and levobupivacaine in an equal dose and concentration for sympathetic block in dogs

BACKGROUND AND OBJECTIVES

The aim of this study was to compare the potency of bupivacaine, ropivacaine, and levobupivacaine in an equal dose and concentration for sympathetic block.

METHODS

We measured mean arterial pressure, heart rate (HR), and right and left brachial artery blood flow (BABF) before and after cervicothoracic sympathetic block in 24 dogs. The experimental protocol was designed as follows: (1) left cervicothoracic sympathetic block with 1.0 mL of 0.25% bupivacaine (n = 8), (2) left cervicothoracic sympathetic block with 1.0 mL of 0.25% ropivacaine (n = 8), and (3) left cervicothoracic sympathetic block with 1.0 mL of 0.25% levobupivacaine (n = 8).

RESULTS

Mean arterial pressure and heart rate did not change significantly throughout the study in either group. Left cervicothoracic sympathetic block with 0.25% bupivacaine increased left BABF significantly from 5 to 100 mins after the block (baseline, 100%; peak at 20 mins after the block, 218% +/- 48%; P < 0.01). Left cervicothoracic sympathetic block with 0.25% ropivacaine increased left BABF significantly from 5 to 100 mins after the block (baseline, 100%; peak at 10 mins after the block, 254 +/- 38%; P < 0.01). Left cervicothoracic sympathetic block with 0.25% levobupivacaine increased left BABF significantly from 5 to 80 mins after the block (baseline, 100%; peak at 20 mins after the block, 183% +/- 38%; P < 0.01).

CONCLUSIONS

Ropivacaine may induce a greater increase in vasodilation than bupivacaine and levobupivacaine at the same dose and concentration for sympathetic block in dogs.

Effect of Methadone on Cardiac Repolarization in Japanese Cancer Patients: A Longitudinal Study

INTRODUCTION

Methadone is known to prolong the QT interval, which could induce lethal arrhythmias such as torsades de pointes. To determine the risk of ventricular arrhythmias in cancer patients using methadone, we measured QT dispersion (QTD) and Tpeak-Tend (TpTe) before and after methadone administration and evaluated the correlations between methadone dosage and cardiac repolarization.

METHODS

We conducted a retrospective observational study with 19 patients undergoing follow-up for cancer pain with methadone. Electrocardiogram (ECG) recordings were obtained from the patients at methadone initiation and 1 week, 1 month, and 2 months later. The QT, corrected QT (QTc), QTD, QTc dispersion (QTcD), TpTe, TpTe/QT, and TpTe/QTc were measured manually via ECG records and analyzed using a repeated measures one-way ANOVA. The correlations between these ECG parameters and each methadone dosage were determined using Spearman's rank correlation coefficient.

RESULTS

The QTD, QTcD, TpTe/QT, and TpTe/QTc remained unchanged, while TpTe was prolonged significantly at 2 months (initiation: 82 ± 17 ms; 2 months: 106 ± 20 ms, p = 0.018). In addition, there was a positive correlation between TpTe and methadone dosage (rs = 0.4, p = 0.041).

CONCLUSIONS

The findings suggested that small or modest doses of methadone could exert dose-dependent effects on cardiac repolarization in cancer patients.

TRIAL REGISTRATION

UMIN Clinical Trials Registry, UMIN000034519.

Five percent, 7.5% or 10% hypertonic saline prevents delayed neuronal death in gerbils

PURPOSE

To clarify the appropriate concentration and dose of hypertonic saline solution (HSS) for preventing delayed neuronal death in the hippocampal CA1 subfield after transient forebrain ischemia in gerbils.

METHODS

Thirty gerbils were randomly assigned to five groups: physiological saline solution (PSS) group, ischemia/reperfusion treated with PSS 2 mL x kg(-1); 5% HSS group, treated with 5% HSS 2 mL x kg(-1); 7.5% HSS group, treated with 7.5% HSS 2 mL x kg(-1); 10% HSS group, treated with 10% HSS 2 mL x kg(-1); 20% HSS group, treated with 20% HSS 2 mL x kg(-1). Transient forebrain ischemia was induced by occluding the bilateral common carotid arteries for four minutes. Five days later, histopathological changes in the hippocampal area were examined, and the degenerative ratio of the pyramidal cells were measured according to the following formula: (number of degenerative pyramidal cells/total number of pyramidal cells per 1 mm of hippocampal CA1 subfield) x 100.

RESULTS

In PSS and 20% groups, neuronal cell damage was observed five days after ischemia. In the other three groups, these changes were not observed. The degenerative ratios of pyramidal cells were as follows; PSS group: 91.6 +/- 5.6%, 5% HSS group: 7.2 +/- 1.6%, 7.5% group: 8.3 +/- 1.4%, 10% HSS group: 6.2 +/- 1.1%, 20% HSS group: 85.8 +/- 8.7% (P < 0.05; PSS and 20% HSS vs three other groups).

CONCLUSION

This study demonstrates that 5, 7.5 or 10% HSS 2 mL x kg(-1) may prevent delayed neuronal death in the hippocampal CA1 subfield after cerebral ischemia/reperfusion in gerbils.

Addition of clonidine increases duration and magnitude of vasodilative effect induced by sympathetic block with mepivacaine in dogs

BACKGROUND AND OBJECTIVES

The aim of this study is to examine the duration and magnitude of vasodilative effect induced by sympathetic block with the addition of clonidine to mepivacaine.

METHODS

We measured mean arterial pressure (MAP), heart rate (HR), and right and left brachial artery blood flow (BABF) before and after stellate ganglion block (SGB) in dogs. The experimental protocol was designed as follows: (1) left SGB using 1.0 mL 0.5% mepivacaine (n = 6) and (2) left SGB using the addition of clonidine 0.5 microg to 1.0 mL 0.5% mepivacaine (n = 6).

RESULTS

MAP and HR did not change significantly throughout the study in either group. Left SGB with mepivacaine increased left BABF significantly from 10 minutes through 50 minutes after SGB (baseline, 100%; peak at 10 minutes after SGB, 176% +/- 28%; P <.01). Left SGB with the addition of clonidine to mepivacaine induced a significant increase of left BABF from 10 minutes through 70 minutes after SGB (baseline, 100%; peak at 10 minutes after SGB, 223% +/- 42%; P <.01). The values of left BABF after SGB with the addition of clonidine to mepivacaine were significantly higher than those of SGB with mepivacaine alone from 10 minutes through 80 minutes after SGB (P <.05). Right BABF decreased significantly after SGB throughout the study in both groups.

CONCLUSIONS

The addition of clonidine increases both duration and magnitude of the vasodilative effect induced by sympathetic block over that caused by mepivacaine alone.

Acute cigarette smoking reduces vasodilative effect induced by sympathetic block in dogs

BACKGROUND AND OBJECTIVES

The aim of this study is to clarify the influence of acute cigarette smoking on vasodilation induced by sympathetic block.

METHODS

We measured mean arterial pressure, heart rate, left brachial artery blood flow (BABF), right femoral artery blood flow (FABF), and plasma catecholamines in dogs to examine the effect of acute cigarette smoking after stellate ganglion block (SGB). The experimental protocol was: (1) Left SGB using 1.0 mL 0.5% mepivacaine without smoking (sham smoking); and (2) left SGB using 1.0 mL 0.5% mepivacaine followed by a single cigarette smoking (nicotine 1 mg) 15 minutes after the block.

RESULTS

SGB induced a significant increase of BABF during the study (baseline, 100%; peak at 10 minutes after SGB, 176% +/- 9%; P <.05) in sham smoking and a significant decrease of FABF from 10 minutes after the block to 20 minutes after sham smoking (baseline, 100%; bottom at 5 minutes after sham smoking, 82% +/- 8%; P <.05). Smoking after SGB induced a significant decrease of BABF 60 minutes after smoking (baseline, 100%; 69% +/- 11%; P <.05) and a significant decrease of FABF during the study (baseline, 100%; bottom at 20 minutes after smoking, 74% +/- 20%; P <.05). Smoking significantly increased plasma norepinephrine and epinephrine through the study.

CONCLUSIONS

Sympathetic block induces a significant increase of peripheral blood flow, but smoking produces a significant decrease in the blood flow in the SGB-induced dilated vessels.

Addition of dexmedetomidine prolongs duration of vasodilation induced by sympathetic block with mepivacaine in dogs

BACKGROUND AND OBJECTIVES

The aim of this study was to examine the duration of vasodilation induced by sympathetic block with the addition of dexmedetomidine to mepivacaine.

METHODS

We measured right and left brachial artery blood flow (BABF) before and after stellate ganglion block used as a sympathetic block in dogs. The experimental protocol was designed as follows: (1) left stellate ganglion block using 1.0 mL 0.5% mepivacaine (n = 8), (2) left stellate ganglion block using the addition of dexmedetomidine 0.5 microg to 1.0 mL 0.5% mepivacaine (n = 8), and (3) left stellate ganglion block using the addition of dexmedetomidine 0.5 microg to 1.0 mL physiological saline solution (n = 8).

RESULTS

Left stellate ganglion block with mepivacaine alone increased left BABF significantly from 5 minutes through 50 minutes after the block (baseline, 100%; peak at 10 minutes after SGB, 181 +/- 27%; P <.01). Left stellate ganglion block with the addition of dexmedetomidine to mepivacaine induced a significant increase of left BABF from 5 minutes through 90 minutes after the block (baseline, 100%; peak at 10 minutes after SGB, 174 +/- 36%; P <.01). Left and right BABF did not change significantly after stellate ganglion block with dexmedetomidine only. Right BABF decreased significantly after left stellate ganglion block with mepivacaine alone or the addition of dexmedetomidine to mepivacaine throughout the study.

CONCLUSIONS

The addition of dexmedetomidine prolongs the duration of vasodilation induced by stellate ganglion block with mepivacaine used for sympathetic block in dogs.

Utility of 6% hydroxyethyl starch 130/0.4 in oral cancer surgeries with a duration of over 6 hours: A retrospective case-control study

To evaluate the utility of 6% hydroxyethyl starch (HES) 130/0.4 in oral cancer surgeries with durations over 6 hours. Using a case-control study design, the investigators enrolled patients who underwent oral cancer surgery involving osteotomy or manipulation near the major blood vessels at the Department of Orofacial Surgery in our hospital between 2017 and 2020. The predictor variable was 6% HES130/0.4. Outcomes included in-out balance and other postoperative parameters pertaining to circulatory maintenance (blood loss, urine volume, infusion volume, blood transfusion volume, albumin dose, hemoglobin levels, blood albumin levels, and doses of vasopressors used to maintain blood pressure), as well as pre- and postoperative renal function, pH, bicarbonate levels, and base excess. Changes in renal function were evaluated by assessing blood urea nitrogen and creatinine levels before surgery and at 1 and 7 days postoperatively. The Mann-Whitney U test was used for between-group comparisons, and Student t test was used for intragroup comparisons. The statistical significance was set at P < .05. A total of 65 patients underwent oral cancer surgery with a duration over 6 hours during the study period. The administration of 6% HES130/0.4 at 22.1 ± 7.5 mL/kg/day did not increase blood loss or the blood transfusion volume. Moreover, patients who were administered 6% HES130/0.4 had a significantly larger mean urine volume and infusion volume than those who were not administered 6% HES130/0.4. The infusion therapy could maintain the urine volume and did not worsen renal function. The results of this study showed that administration of 6% HES130/0.4 at a dose lower than 25 mL/kg in patients undergoing oral cancer surgery over 6 hours was effective for circulation maintenance but did not increase the intraoperative blood loss or transfusion volume. This treatment did not cause any dilutional metabolic acidosis or renal dysfunction.

[Insertion of an epidural catheter from the surgical wound for postoperative analgesia--a case report]

A 62-year-old male was scheduled for discectomy for lumbar disc herniation. He had bronchial asthma, and his asthma was induced by nonsteroidal anti-inflammatory drugs. We decided to use continuous epidural block for postoperative analgesia. However, he was frightened of insertion of an epidural catheter. Therefore, we planned to insert the epidural catheter before the end of surgery under general anesthesia. It was easily placed at L 5-S 1 interspace using a Tuohy needle from the surgical wound, and the contrast medium 5 ml was injected through the epidural catheter to confirm the placement. After the surgery, continuous epidural block with local anesthetics was used for two days. He did not complain of severe pain postoperatively.

[Buprenorphine transdermal patch (Norspan tape)]

Buprenorphine is a chemically synthesized opioid characterized as the partial mu agonist and kappa antagonist, and transdermal buprenorphine patch will be considered useful as a strong analgesic with fewer psychological side effects in the treatment of chronic non-cancer pain. Use of transdermal buprenorphine should be limited for pain relief of intractable muscle skeletal pain that cannot be alleviated with other analgesics. To avoid severe complication and drug abuse or addiction, assessment of pain and medical history including drug dependence by medical team are important before administration of transdermal buprenorphine. Moreover, side effects such as nausea, vomiting, constipation, erythema and itching, loss of appetite should be treated appropriately. When transdermal buprenorphine is administered to chronic pain patients, physicians must examine the condition of patients regularly at an outpatient clinic. Moreover, decreasing and discontinuation of opioid including transdermal buprenorphine should always be considered during the treatment. Most important objective of chronic pain treatment is to improve QOL and ADL of patients.

[Effect of hypertonic saline solution on delayed neuronal death]

This experiment was performed to investigate whether hypertonic saline has a preventive effect on delayed neuronal death in the CA1 subfield of the hippocampus. Twenty gerbils were used, and after being anesthetized by inhalation of 1% halothane, both common carotid arteries were occluded for 2.5 min. The animals were injected intravenously with 2 ml/kg of 10% NaCl immediately after reperfusion, and 2 ml/kg of physiological saline solution was used in the same manner in a control group. Five days later, histopathological changes in the CA1 subfield were observed by staining with hematoxylin-eosin and examining sections of the brain under a light microscope. Degenerative or necrotic pyramidal cells exhibited cell shrinkage, nuclear pyknosis, dark staining of the cytoplasm vacuolation and disappearance of the radial striated zone. The pyramidal cell degeneration rate in a 1 mm length of CA1 subfield was 95.6 +/- 1.6% in the ischemia-reperfusion-saline group and 7.1 +/- 3.0% in ischemia-reperfusion-hypertonic saline group, and the difference was statistically significant. This study verified that hypertonic saline prevented delayed neuronal death in the CA1 subfield of hippocampal area after ischemia-reperfusion.

[Anesthetic management for electroconvulsive therapy (ECT) in a patient with primary aldosteronism]

A 68-year-old male with primary aldosteronism who was scheduled for electroconvulsive therapy (ECT). We used propofol and suxamethonium to induce anesthesia, and measured plasma levels of aldosterone to evaluate the influence of ECT during anesthesia. Although plasma levels of aldosterone increased gradually after ECT, there were no complications including severe hypertension or arrhythmia perioperatively.