Recovery Profile and Patient Satisfaction After Ambulatory Anesthesia for Dental Treatment-A Crossover Comparison Between Propofol and Sevoflurane.

The purpose of this study was to determine which anesthetic was preferable for ambulatory anesthesia: propofol alone or sevoflurane alone. A crossover study was performed to compare the recovery profile and patient satisfaction after 2 anesthesia methods. Twenty healthy patients with severe anxiety toward dental treatment undergoing 2 sessions of day-case dental treatment received either propofol or sevoflurane anesthesia. The order of these methods was randomized. The depths of anesthesia were kept constant using bispectral index (BIS) monitoring. Observations on recovery profiles were performed in the emergence phase, in the recovery phase, and 24 hours after discharge. Patient satisfaction and preference were obtained by a questionnaire. Most of the recovery profiles in the emergence phase such as time to eye opening to respond to verbal command, time to BIS ≥ 75, and time to extubation were shorter in the sevoflurane group than in the propofol group. All recovery profiles in the recovery phase showed no differences between the 2 groups. Based on the subject's satisfaction and preference, propofol was evaluated as a better anesthetic for ambulatory anesthesia than sevoflurane. Higher patient satisfaction and a greater preference for future dental treatment were revealed for propofol anesthesia. Propofol may be more suitable for ambulatory anesthesia for dental treatment.

IV ATP potentiates midazolam sedation as assessed by bispectral index.

In this study, by measuring bispectral index (BIS), we tested the hypothesis that intravenous adenosine 5'-triphosphate (ATP) infusion would deepen the level of midazolam-induced sedation. Ten healthy volunteers underwent 2 experiments with at least 2 weeks' interval: immediately after intravenous bolus administration of midazolam (0.04 mg/kg), they received continuous infusion of either ATP infusion (100 µg/kg/min) or placebo (saline) for 40 minutes in a double-blind, randomized, crossover manner. Changes in BIS values and responsiveness to verbal command as well as cardiorespiratory variables were observed throughout the study periods. Administration of midazolam alone reduced BIS value from control: 97 ± 1 to 68 ± 18 at 25 minutes, which was accompanied by significant cardiopulmonary depressant effects, while maintaining responsiveness to verbal command (consciousness) throughout the study period. Coadministration of ATP with midazolam further reduced BIS value to 51 ± 13, associated with complete loss of consciousness without adverse effect on the cardiorespiratory systems. We conclude that the addition of ATP infusion to midazolam significantly enhances midazolam sedation without disturbing cardiorespiratory functions.

Pain Management for Nerve Injury following Dental Implant Surgery at Tokyo Dental College Hospital.

By allowing reconstruction of compromised occlusion, dental implants contribute to an improvement in quality of life (QOL) and diet. Injury to a nerve during such treatment, however, can result in a sudden decline in QOL. And once a nerve has been injured, the chances of a full recovery are slim unless the damage is only slight. If such damage causes neuropathic pain severe enough to prevent sleep, the patient's QOL will deteriorate dramatically. While damage to skin tissue or bone invariably heals over time, damage to nerves does not, indicating the need to avoid such injury while performing implant insertion, for example. This means not relying solely on X-ray images, which can be rather unclear, but also using computed tomography to allow preoperative planning and intraoperative execution to be performed as accurately as possible. Moreover, if sensory damage does occur it is essential to avoid breaking the bond of trust between dentist and patient by giving false assurances of recovery. In such cases, appropriate measures must be taken promptly. This paper describes pain management for nerve injury following dental implant surgery at the Orofacial Pain Center of Tokyo Dental College Suidoubashi Hospital.

Midazolam increases bite force during intravenous sedation.

PURPOSE: Although there have been many reports on the effects of midazolam on vital function and the recovery profile, little is known about muscle power during sedation. The purpose of this study was to investigate the effects of midazolam on muscle power during moderate sedation. MATERIALS AND METHODS: The subjects were 20 male volunteers classified as American Society of Anesthesiologists physical status I. Each subject underwent 2 experiments in a randomized crossover manner (midazolam and control groups). After baseline data were obtained, midazolam (0.05 mg/kg) was administered. Thirty minutes after midazolam administration, flumazenil (0.5 mg) was administered to antagonize the sedative effects of midazolam in the midazolam group. Heart rate, noninvasive blood pressure, arterial oxygen saturation, respiratory rate, and the bispectral index value were monitored. The Observer's Assessment of Alertness/Sedation scale and the correct-answer rate of the Stroop color word test were assessed. To evaluate muscle power, grip strength and bite force were measured. After baseline measurement, all variables were measured 2, 5, 10, 20, and 30 minutes after midazolam administration and 5, 10, and 20 minutes after flumazenil administration. For statistical comparisons, repeated measures analysis of variance, the Friedman χ(2) test, and the Student t test for paired samples were used. RESULTS: No significant changes were observed for any variable in the control group. In the midazolam group, the bispectral index value and the Observer's Assessment of Alertness/Sedation scale decreased during midazolam sedation. The correct-answer rate of the Stroop color word test decreased 5 and 10 minutes after midazolam administration. Grip strength decreased during midazolam sedation. Bite force increased immediately after midazolam administration and remained increased even after flumazenil administration. CONCLUSIONS: Although the detailed mechanisms are unknown, bite force increases despite the muscle-relaxant action of midazolam during sedation and persists even with flumazenil reversal.

Oral mucosal injection of a local anesthetic solution containing epinephrine enhances muscle relaxant effects of rocuronium.

The purpose of this study was to examine how submucosal injection of a clinically relevant dose of a lidocaine hydrochloride solution containing epinephrine affects the muscle relaxant effects of rocuronium bromide. Sixteen patients scheduled for orthognathic surgery participated in this study. All patients were induced with fentanyl citrate, a target-controlled infusion of propofol and rocuronium bromide. Anesthesia was maintained by total intravenous anesthesia. After nasotracheal intubation, an infusion of rocuronium bromide was started at 7 µg/kg/min, and the infusion rate was then adjusted to maintain a train of four (TOF) ratio at 10 to 15%. The TOF ratio just prior to oral mucosal injection of a 1% lidocaine hydrochloride solution containing 10 µg/mL epinephrine (LE) was taken as the baseline. TOF ratio was observed for 20 minutes, with 1-minute intervals following the start of injection. Mean epinephrine dose was 85.6 ± 18.6 µg and mean infusion rate of rocuronium bromide was 6.3 ± 1.6 µg/kg/min. TOF ratio began to decrease 2 minutes after the injection of LE, reached the minimum value at 3.1 ± 3.6% 12 minutes after the injection, and then began to recover. We conclude that oral mucosal injection of LE enhances the muscle relaxant effects of rocuronium bromide.

Tissue blood flow reductions induced by remifentanil in rabbits and the effect of naloxone and phentolamine on these changes.

OBJECTIVES: The purpose of this study was to investigate the effects of naloxone and phentolamine on the blood flow changes in rabbit oral tissue induced by remifentanil during sevoflurane anesthesia. MATERIALS AND METHODS: Male Japan White rabbits were anesthetized with sevoflurane under mechanical ventilation. Remifentanil was continuously infused at a rate of 0.4 µg/kg/min. Naloxone 0.01 mg/kg or phentolamine 0.01 mg/kg was administered during remifentanil infusion. Observed variables were systolic and diastolic blood pressures, mean arterial pressure, heart rate, common carotid artery blood flow, tongue mucosal blood flow, mandibular bone marrow blood flow, masseter muscle blood flow, and upper and lower alveolar tissue blood flows. The common carotid artery blood flow was monitored continuously using an ultrasonic blood flowmeter. Tongue mucosal blood flow was monitored continuously using a laser Doppler blood flowmeter. Mandibular bone marrow blood flow, masseter muscle blood flow, and upper and lower alveolar tissue blood flows were measured using a hydrogen clearance tissue blood flowmeter. One-way analysis of variance for repeated measurements followed by the Student-Newman-Keuls test was used. RESULTS: Remifentanil produced decreases in the heart rate, systolic blood pressure, and common carotid artery blood flow by about 15% and mandibular bone marrow blood flow, masseter muscle blood flow, and upper and lower alveolar tissue blood flows by about 30%. In the naloxone group, all variables recovered after naloxone administration. In contrast, in the phentolamine group, tissue blood flow recovered, whereas heart rate, systolic blood pressure, and common carotid artery blood flow did not recover after phentolamine administration. CONCLUSIONS: Remifentanil deceased oral tissue blood flow and systemic hemodynamic variables. Naloxone and phentolamine produced a recovery of oral tissue blood flow with and without systemic hemodynamic recovery, respectively.

Unilateral stellate ganglion block produces bidirectional changes in tissue oxygen tension of the mental nerve in rabbits.

PURPOSE: The purpose of this study was to investigate changes in the tissue oxygen tension (PO(2)) of the mental nerve bilaterally before and after unilateral stellate ganglion block (SGB). MATERIALS AND METHODS: Nine male Japan white rabbits were used. Anesthesia was maintained by a continuous infusion of propofol under mechanical ventilation with room air. For the SGB, the tip of a 26-gauge needle was placed on the left transverse process of the cervical vertebra; 0.2 mL of 1% lidocaine solution was injected. Data were recorded immediately before SGB and when the maximal change in PO(2) after SGB was observed. Observed variables were heart rate, blood pressure, common carotid arterial blood flow, tongue mucosal blood flow, left PO(2), and right PO(2). RESULTS: PO(2) showed maximal changes 7.9 ± 2.0 minutes after SGB. No changes were observed in heart rate and blood pressure after SGB. Common carotid arterial blood flow, tongue mucosal blood flow, and left PO(2) were increased by 106.4% ± 39.8%, 36.2% ± 35.2%, and 38.7% ± 19.8%, respectively, after SGB. In contrast, right PO(2) was decreased by 29.8% ± 7.4% after SGB. CONCLUSIONS: These results suggest that unilateral SGB produces bidirectional changes in the PO(2) of the mental nerve and that SGB decreases the PO(2) of the mental nerve on the contralateral side.

Localization of 14C-labeled 2% lidocaine hydrochloride after intraosseous anesthesia in the rabbit.

OBJECTIVE: The purpose of this study was to investigate the tissue distribution of lidocaine hydrochloride in mandibular bone marrow after intraosseous anesthesia (IOA) in rabbits. METHODS: We used macroautoradiography to examine the tissue distribution of a (14)C-labeled 2% lidocaine hydrochloride solution containing 1:80,000 epinephrine ((14)C-lidocaine). Under general anesthesia, (14)C-lidocaine was injected intraosseously or paraperiosteally. After IOA, animals were divided into three groups and observed at 1 (IOA-1), 5 (IOA-5), and 10 minutes (IOA-10) after injection. After infiltration anesthesia (IA), animals were observed at 1 minute after injection. RESULTS: The accumulation of (14)C-lidocaine was observed around the injection site in both the IA and the IOA groups. Paraperiosteally injected (14)C-lidocaine diffused to the surrounding tissues such as the lip, whereas IOA showed concentrated accumulation around the root apex throughout the experiment. The distribution area was significantly smaller in the IOA-1 group than in the IA group. The distribution area in the IOA-5 group was larger than those in the IOA-1 and IOA-10 groups. CONCLUSIONS: The accumulation of (14)C-lidocaine injected by IOA in rabbits was concentrated around the root apex. These results may explain the rapid onset time of IOA.

Propofol dose-dependently increases bite force during sedation.

PURPOSE: The purpose of this study was to investigate the dose-dependent effects of propofol on cognitive function and muscle power as well as vital functions. MATERIALS AND METHODS: Twenty volunteers participated in this study. Each subject underwent 2 experiments in a randomized crossover manner (propofol group and control group). After control data were obtained, propofol at predicted effect site concentrations of 0.4, 0.8, 1.2, 1.6, and 2.0 µg/mL was infused in the propofol group using a target controlled infusion system. Heart rate, noninvasive blood pressure, arterial oxygen saturation, respiratory rate, and bispectral index value were monitored. Observer's assessment of alertness/sedation and the correct answer rate of the Stroop color word test were assessed. Muscle power, grip strength and bite force were measured. RESULTS: In the propofol group, the bispectral index value and observer's assessment of alertness/sedation scale dose-dependently reduced. At the predicted effect site propofol concentration of 2.0 µg/mL, 6 subjects became unconscious. The correct answer rate of Stroop color word test reduced at the predicted effect site propofol concentration of 1.6 and 2.0 µg/mL. Grip strength slightly increased at the predicted effect site propofol concentration of 1.2 µg/mL or less, and bite force dose-dependently increased. At the predicted effect site propofol concentration of 2.0 µg/mL, both muscle powers began to decrease. Bite force dose-dependently increased and reached the maximum at the predicted effect site propofol concentration of 1.6 µg/mL. CONCLUSION: Although the detailed mechanisms are unknown, propofol dose-dependently increases bite force during minimal and moderate sedation.

Risk factors for nausea and vomiting after day care general anesthesia in mentally challenged patients undergoing dental treatment.

Clinically, the incidence of postoperative nausea and vomiting (PONV) may be higher in mentally challenged patients than in normal healthy patients. The aim of this study was to investigate the risk factors for PONV after day care general anesthesia in mentally challenged patients undergoing dental treatment. We analyzed data on 231 day care general anesthesia cases involving mentally challenged patients undergoing dental treatment. Anesthetic records for the past 5 years were investigated retrospectively. Ten items (age, body weight, sex, duration of general anesthesia, use of propofol, use of sevoflurane, use of nitrous oxide, use of neostigmine, treatment accompanied with bleeding, and transfusion volume) were selected as risk factors for PONV. Postoperative nausea and vomiting was evaluated using the postoperative check sheet and linear discriminant analysis was performed to distinguish PONV incidence using the 10 items as independent variables. The reliability of the linear discriminant function was evaluated using a misjudgment rate and information criteria (AIC). Postoperative nausea and vomiting was observed in 13 cases out of 231 cases. The discriminant function with the smallest AIC (-25.0718) consisted of two independent variables: y=-0.077x(1)-0.001x(2)+0.0716(x(1)=use of propofol, x(2)=age). The misjudgment rate was 31.6%. This result suggests that PONV decreases when propofol is used and that the incidence of PONV decreases with age. To investigate other risk factors, an additional analysis was performed using 83 out of the 231 cases in which sevoflurane was used as an anesthetic agent. The results of the subgroup analysis suggest that the incidence of PONV decreases in male patients and higher weight patients, although the patient's body weight may be related to age, as the study cohort included many children. It is suggested that the major risks for PONV in mentally challenged patients after day care general anesthesia are no use of propofol, lower age, female sex and lower weight.

Dose-dependent remifentanil decreases oral tissue blood flow during sevoflurane and propofol anesthesia in rabbits.

PURPOSE: The aim of this study was to investigate the effect of remifentanil continuous infusion on the blood flow in rabbit oral tissue during propofol and sevoflurane anesthesia, as well as its dose dependency. MATERIALS AND METHODS: Sixteen male tracheotomized Japan white rabbits were anesthetized with propofol or sevoflurane under mechanical ventilation. The infusion rate of remifentanil was 0.1, 0.2, 0.4, 0.8, and 1.6 µg·kg(-1)·min(-1), respectively, for 20 minutes. Observed variables were systolic blood pressure (SBP), diastolic blood pressure, mean arterial pressure (MAP), heart rate (HR), common carotid artery blood flow, tongue mucosal blood flow (TBF), mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), upper alveolar tissue blood flow (UBF), and lower alveolar tissue blood flow (LBF). RESULTS: HR, SBP, MAP, TBF, BBF, MBF, UBF, and LBF showed dose-dependent decreases during remifentanil infusion with both propofol and sevoflurane anesthesia. The decreases in BBF, MBF, UBF, and LBF explained as a percent change were greater than those in HR, SBP, MAP, and TBF. In the sevoflurane group, there were no changes in diastolic blood pressure and common carotid artery blood flow during remifentanil infusion. CONCLUSION: Our findings suggest that infusion of remifentanil reduces TBF, BBF, MBF, UBF, and LBF in a dose-dependent manner without a significant reduction in MAP during propofol and sevoflurane anesthesia.

A case of zoster sine herpete of the trigeminal nerve.

Varicella-zoster virus reactivation causes zoster (shingles), a syndrome characterized by severe pain and a vesicular rash. The present report details a case of varicella-zoster virus reactivation of the maxillary and mandibular division of the right trigeminal nerve without evidence of vesicular rash (zoster sine herpete). It is difficult to identify owing to no typical clinical signs such as vesicular eruption. Zoster sine herpete of the trigeminal nerve, in particular, is rarely reported. In this case, the diagnosis was based on clinical findings and was supported by the demonstration of an immunoglobulin G antibody. Zoster sine herpete of the trigeminal nerve, in particular, should be considered in patients with severe facial pain over specific dermatomes, if they do not demonstrate appreciable findings of traumatic neuropathy, tumor or herpes zoster.

Anesthetic management of a child with Aicardi syndrome undergoing laparoscopic Nissen's fundoplication: a case report.

Aicardi syndrome (AS) is a rare congenital syndrome and is characterized by the triad of infantile spasm, agenesis of the corpus callosum, and anomaly of chorioretinal lacunae. We here report a case of a patient with AS under general anesthesia. Although there is no report in which muscle relaxants were used in AS patients, vecuronium bromide was used for artificial pneumoperitoneum in this case. Careful management is important for AS patients during an operation that significantly affects respiratory function. In addition, it is possible that muscle relaxants be administered safely in AS patients. Careful monitoring such as epileptiform electroencephalogram and bispectral index monitors may be needed for the early detection of epileptic activities.

Diversity of opioid requirements for postoperative pain control following oral surgery--is it affected by polymorphism of the µ-opioid receptor?

We experience individual differences in pain and sensitivity to analgesics clinically. Genetic factors are known to influence individual difference. Polymorphisms in the human OPRM1 gene, which encodes the µ-opioid receptors, may be associated with the clinical effects of opioid analgesics. The purpose of this study was to determine whether any of the 5 common single-nucleotide polymorphisms (SNPs) of the OPRM1 gene could affect the antinociceptive effect of fentanyl. Fentanyl was less effective in subjects with the G allele of the OPRM1 A118G SNP than in those with the A allele, and subjects with the G allele required more fentanyl for adequate postoperative pain control than those with the A allele. In the future, identifying SNPs might give us information to modulate the analgesic dosage of opioid individually for better pain control. Factors underlying individual differences in sensitivity to pain other than genetic factors may include environmental and psychological factors. We therefore examined the effects of preoperative anxiety on the analgesic efficacy of fentanyl in patients undergoing sagittal split mandibular osteotomy (SSMO). From among the patients enrolled in the study, 60 patients (male/female: 18/42, age: 24.6 ± 6.7 years) who gave informed consent were examined for correlations between preoperative trait/state anxiety, as measured by the state-trait anxiety inventory (STAI) on the day before surgery, and postoperative consumption of patient-controlled analgesia (PCA) fentanyl and visual analog scale (VAS) assessment by patients. Levels of trait and state anxieties measured by the STAI were correlated with neither the consumption of PCA fentanyl nor postoperative VAS assessment. These findings suggest that psychological factors are unlikely to affect postoperative pain or the use of analgesics.

Rocuronium and vecuronium do not affect mandibular bone marrow and masseter muscular blood flow in rabbits.

PURPOSE: The goal of this study was to investigate the effect of rocuronium and vecuronium continuous infusion on oral tissue blood flow in rabbits. MATERIALS AND METHODS: We used 8 male Japan White rabbits. The infusion rates of rocuronium were 7, 14, and 28 microg kg(-1) min(-1) for 20 minutes, in this order. After rocuronium was discontinued and body movement confirmed, continuous infusion of vecuronium was started. The infusion rates of vecuronium were 1.6, 3.2, and 6.4 microg kg(-1) min(-1) for 20 minutes, in this order. Observed variables were systolic blood pressure, diastolic blood pressure, mean arterial pressure, heart rate, common carotid artery blood flow, tongue mucosal blood flow, oxygen partial pressure of the mandibular bone marrow, and oxygen partial pressure of the masseter muscle. RESULTS: Heart rate in both groups tended to decrease depending on the infusion rate. Common carotid artery blood flow in the rocuronium group was increased depending on the infusion rate. Tongue mucosal blood flow in the vecuronium group was decreased depending on the infusion rate. There were no differences in diastolic blood pressure, mean arterial pressure, oxygen partial pressure of the mandibular bone marrow, and oxygen partial pressure of the masseter muscle between the 2 groups. Systolic blood pressure in both groups showed no major change. CONCLUSION: Rocuronium and vecuronium did not change mandibular bone marrow and masseter muscular blood flows. Vecuronium decreased tongue mucosal blood flow depending on the infusion rate.

Felypressin, but not epinephrine, reduces myocardial oxygen tension after an injection of dental local anesthetic solution at routine doses.

PURPOSE: The aim of this study was to evaluate the effect of epinephrine (Epi) or felypressin (Fely) contained in dental local anesthetics on myocardial oxygen balance. MATERIALS AND METHODS: Male Japanese White tracheotomized rabbits were anesthetized with isoflurane. Three doses of 0.18, 0.36, and 0.72 mL of 2% lidocaine hydrochloride containing 1:80,000 Epi or 3% prilocaine hydrochloride containing Fely 0.03 IU/mL were injected into the rabbit tongue muscle. These doses were equivalent to 2, 4, and 8 of dental local anesthetic cartridges in humans weighing 50 kg by body weight correction, respectively. Heart rate, blood pressure, aortic blood flow, myocardial tissue blood flow, and myocardial tissue oxygen tension were continuously monitored. Data were recorded immediately before and 10, 20, 30, and 60 minutes after the injection. RESULTS: Heart rate decreased in the Fely group. Systolic blood pressure increased in the Epi group, and diastolic blood pressure increased in both groups. Aortic blood flow and myocardial tissue blood flow increased, whereas myocardial tissue oxygen tension did not change in the Epi group. In contrast, aortic blood flow, myocardial tissue blood flow, and myocardial tissue oxygen tension decreased in the Fely group. CONCLUSION: It is suggested that Fely, but not Epi, decreases myocardial oxygen tension and aggravates myocardial oxygen demand/supply balance even after an injection of dental local anesthetic solution at routine doses.

A comparison of propofol and dexmedetomidine for intravenous sedation: a randomized, crossover study of the effects on the central and autonomic nervous systems.

We compared, in volunteers, the effect of propofol (PROP) and dexmedetomidine (DEX) sedation on autonomic nervous activities and subjective feelings during psychological stresses. In a crossover design, 25 subjects received PROP and DEX titrated to a bispectral index value of 75 to 85. Heart rate, heart rate variability, and salivary alpha-amylase (objective indices) and a faces anxiety scale (subjective index) were assessed. Subjects were asked their preference between 2 sedatives. Objective indices showed similar changes in both groups. The faces anxiety scale decreased only in the PROP group and subjects preferred PROP. Propofol more effectively suppressed anxious feelings compared with DEX during sedation.

Midazolam more effectively suppresses sympathetic activations and reduces stress feelings during mental arithmetic task than propofol.

PURPOSE: The aim of the present study was to examine the effect of intravenous midazolam and propofol sedation on autonomic nervous activities during psychological stress, and whether these results are associated with changes in subjective stress feelings. MATERIALS AND METHODS: Seven healthy male volunteers were included in a randomized crossover manner. The heart rate (HR), HR variability, arterial oxygen saturation, and bispectral index value were continuously monitored. A mental arithmetic task for 7 minutes was given with or without intravenous sedation with midazolam or propofol. A bispectral index value of 75 to 85 and an Observer's Assessment of Alertness/Sedation score of 4 were the targeted sedation level in both groups. HR variability was assessed using the power spectral analysis (low-frequency [LF] and high-frequency [HF] components and LF/HF ratio). The faces anxiety scale was used to grade their stress feelings after each mental arithmetic task. RESULTS: During the mental arithmetic task with intravenous sedation, no differences were found in the bispectral index values, arterial oxygen saturation, or the results of the mental arithmetic task between the 2 groups. The HR, LF/HF ratio, and normalized unit LF increased, and the normalized unit HF decreased in both groups. However, the percentage of changes in LF/HF ratio, normalized unit LF, and normalized unit HF were smaller in the midazolam group. In addition, the reduction in faces anxiety scale was greater in the midazolam group. CONCLUSIONS: These results suggest that midazolam more effectively suppresses sympathetic nervous activation and reduces subjective stress feelings during a mental arithmetic task than propofol.

Redistribution of tissue blood flow after stellate ganglion block in the rabbit.

BACKGROUND AND OBJECTIVES: The goal of this study was to compare tissue blood flow at various sites before and after stellate ganglion block (SGB) and to discuss the redistribution of tissue blood flow after SGB. METHODS: We studied 16 male Japanese white rabbits. For SGB, the tip of a 26-gauge needle was placed on the left transverse process of the cervical vertebra, 1 to 2 mm caudal to the cricoid cartilage. Either 0.2 mL of 1% lidocaine (lidocaine group) or normal saline solution (saline group) was injected. In the lidocaine group, data were recorded immediately before SGB and at the time when the maximal change in the common carotid arterial blood flow was observed after SGB. In the saline group, data were recorded immediately before SGB and 3 minutes after SGB. Observed variables were blood pressure, heart rate, common carotid arterial blood flow, tongue mucosal blood flow, mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), quadriceps muscle blood flow, liver blood flow, and renal blood flow. RESULTS: Common carotid arterial blood flow, tongue mucosal blood flow, BBF, and MBF on the block side were increased, whereas BBF and MBF on the nonblock side and quadriceps muscle blood flow, liver blood flow, and renal blood flow were decreased after SGB in the lidocaine group. CONCLUSIONS: These results indicate that lower limb and visceral blood flow as well as blood flow on the nonblock side are redistributed to the block side after SGB. Redistribution from peripheral tissue may have a more important role than that of visceral blood flow redistribution after SGB.

Relationship between oral tissue blood flow and oxygen tension in rabbit.

Several studies have reported tissue blood flow and tissue oxygen tension during anesthesia, whereas there are few reports that discuss the relationship between tissue blood flow and tissue oxygen tension. The goal of this study was to investigate the relationship between these two variables before and after stellate ganglion block (SGB). We utilized 8 male Japan White rabbits. Anesthesia was maintained with propofol. For SGB, 0.2 ml of 1% lidocaine was injected and changes in mandibular bone marrow blood flow (BBF) and mandibular bone marrow oxygen tension (PbO(2)) were observed (Group B). After the observed variables completely recovered, 0.2 ml of 1% lidocaine was again injected and changes in masseter muscle blood flow (MBF) and masseter muscle oxygen tension (PmO(2)) were observed (Group M). The observed variables were hemodynamic parameters, common carotid artery blood flow, L (left side)-BBF, R (right side)-BBF, L-PbO(2), R-PbO(2), L-MBF, R-MBF, L-PmO(2) and R-PmO(2). In both groups, positive correlations (r=0.99; y=0.68x - 3.49 in Group B and r=0.99; y=0.62x + 0.47 in Group M) were observed when tissue blood flow was set at the X-axis and tissue oxygen tension at the Y-axis. In contrast, when tissue blood flow was set at the Y-axis and tissue oxygen tension at the X-axis, two regression lines almost overlapped (y=1.47x + 5.12 in Group B and y=1.59x - 0.28 in Group M). Therefore, it is estimated that tissue blood flow increases by approximately 15 ml/min/100g when tissue oxygen tension increases by 10 mmHg. In conclusion, there is a positive correlation between tissue blood flow and tissue oxygen tension. Changes in tissue oxygen tension should reflect the increase or decrease in tissue blood flow.