[Incidence and onset time of fentanyl-induced cough depends on the dose of IV fentanyl].

BACKGROUND: IV fentanyl en bolus can provoke cough reflex. We evaluated the effects of the IV fentanyl dose on the incidence and onset time of fentanyl-induced cough. METHODS: Tree hundred and eighteen ASA physical status I - II patients scheduled for oral surgery under general anesthesia were randomly assigned to receive 1 microg x kg(-1), 3 microg x kg(-1) or 5 microg x kg(-1) of IV fentanyl (n = 106 for each group). We recorded, in each patient, presence/absence and onset time, if present, of cough reflex for 60 seconds after fentanyl injection. RESULTS: The incidences of fentanyl-induced cough were 6.6%, 22.5%, and 44.3% in the 1 microg x kg(-1), 3 microg x kg(-1), and 5 microg x kg(-1) groups, respectively. The onset times of fentanyl-induced cough were 29.0 +/- 11.8 seconds, 22.5 +/- 7.9 seconds, and 19.5 +/- 7.0 seconds in the 1 microg x kg(-1), 3 microg x kg(-1), and 5 microg x kg(-1) groups, respectively. CONCLUSIONS: The results indicated that the incidence of fentanyl-induced cough increased, and the onset time decreased, with the increasing dose of fentanyl.

Changes in partial pressure of arterial carbon dioxide induces redistribution of oral tissue blood flow in the rabbit.

PURPOSE: The purpose of this study was to investigate the effect of changes in partial pressure of arterial CO(2) (PaCO(2)) on oral tissue blood flow. MATERIALS AND METHODS: Twenty male tracheotomized Japan white rabbits were anesthetized with isoflurane (ISO) or propofol (PROP) under mechanical ventilation. Observed variables included heart rate, blood pressure, common carotid artery blood flow (CBF), and tissue blood flow of the mandibular bone marrow (BBF), the masseter muscle (MBF), and the mandibular periosteum (PBF). After completion of experimental preparation, CO(2) was added to inspired gas to change the inspired CO(2) tension. Measurements were performed with end-tidal CO(2) tension (ETCO(2)) maintained at 30, 40, 50, and 60 mmHg. RESULTS: Heart rate in both groups gradually decreased with increasing ETCO(2). In contrast, both systolic and diastolic arterial pressures gradually increased with increasing ETCO(2). Both CBF and BBF increased and MBF decreased with increasing ETCO(2). PBF showed no change throughout the experiment. A positive relationship was observed between CBF and BBF; in contrast, a negative relationship was observed between CBF and MBF. CONCLUSION: Changes in PaCO(2) may induce a redistribution of oral tissue blood flow during both ISO and PROP anesthesia.

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.