Large-dose epinephrine reduces skeletal muscle blood flow under general anesthesia in rabbits.

The goal of this study was to investigate the effect of an epinephrine continuous infusion on muscle blood flow in rabbits. Sixteen male Japan White rabbits were randomly allocated to 1 of 2 groups: epinephrine continuous infusion at 0.01 µg/kg/min (Ep-0.01 group, n = 8) and at 0.1 µg/kg/ min (Ep-0.1 group, n = 8). The observed variables were heart rate, femoral artery blood pressure, common carotid artery blood flow (CCBF), masseter muscle blood flow (MBF), and quadriceps muscle blood flow (QBF). In the Ep-0.01 group, CCBF, MBF, and QBF were increased by 14, 22, and 21% from respective control values. In contrast, in the Ep-0.1 group, CCBF, MBF and QBF were decreased by 10, 30, and 27% from respective control values. There were no differences in the percentage change between MBF and QBF during epinephrine continuous infusion. Positive correlations were observed between CCBF and MBF and between CCBF and QBF. In conclusion, skeletal muscle blood flow was increased during the small-dose epinephrine infusion, whereas it was decreased during large-dose infusion.

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.

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.

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.

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.

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.

Epinephrine in local anesthetic cancels increase in tongue mucosal blood flow after stellate ganglion block in rabbit.

The goal of this study was to compare oral mucosal blood flow and duration of anesthetic action after stellate ganglion block (SGB) using lidocaine, with or without epinephrine, and discuss the effect of epinephrine on SGB. Duration of anesthetic action was defined as elapsed time from finish of injection to recovery of common carotid blood flow (CCBF) to within+/-5% of respective control value. Male Japan White rabbits were anesthetized with isoflurane and mechanically ventilated. Common carotid blood flow and tongue mucosal tissue blood flow (TMBF) were measured with an ultrasound flowmeter and laser Doppler flowmeter, respectively. End-tidal partial pressure of carbon dioxide (ETCO(2)) and hemodynamic variables were continuously monitored, including heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP). For SGB, the tip of the needle was placed on the left transverse process of the cervical vertebra, 1-2 mm caudal to the cricoid cartilage. Either 0.1 ml of 1% lidocaine (Group L) or 1% lidocaine containing 10 mug/ml epinephrine (Group LE) was injected for SGB. There were no differences in values at immediately before SGB and at the time when maximal change in CCBF was observed after SGB for ETCO(2), HR, SBP, DBP or MAP in either group. CCBF showed a significant increase in Group L after SGB. In contrast, CCBF only showed a slight increase in Group LE. TMBF showed a significant increase in Group L after SGB, but not in Group LE. No differences in time required for maximal effect were observed between the two groups. In contrast, duration of anesthetic action in Group LE was significantly longer than that in Group L. Addition of epinephrine to local anesthetic solutions is not suitable for SGB, as it may not facilitate an increase in tissue blood flow, which is the primary objective of SGB.