The effects of epinephrine in local anesthetics on plasma catecholamine and hemodynamic responses.

In order to clarify the influence of epinephrine in local anesthetics on endogenous epinephrine, we examined the concentration of plasma catecholamines (epinephrine and norepinephrine) and hemodynamics by administering 4 ml of 2% lidocaine containing different concentrations of epinephrine. Forty-three healthy adult male volunteers were divided into five groups according to epinephrine concentration: 0-microg (group I), 10-microg (group II), 20-microg (group III), 40-microg (group IV), and 50-microg (group V). The parameters were examined immediately, and at 1, 2, 3, 4, 5, 10, 15, and 20 min after the injection. In groups II, III, IV, and V, the plasma epinephrine concentration was elevated to peak at 5 min after the injection, after which it started to decline. The amount of increase in the plasma epinephrine concentration at 5 min showed a highly positive correlation with the amount of epinephrine added to the local anesthetic in groups II, III, and IV. In group V the plasma epinephrine concentration showed a marked increase as compared to the baseline level. Plasma norepinephrine concentrations were found to be significantly elevated at 15 and 20 min in group V. A decrease in systolic blood pressure was observed at 4 and 5 min in group II. A decrease in diastolic blood pressure was observed at 5 min in group II; at 3, 4, and 5 min in group IV; and at 2, 3, 4, and 5 min in group V. Heart rate revealed no significant differences from baseline level in any of the groups and there were no significant differences among the groups. It is suggested that exogenous epinephrine added to a local anesthetic may stimulate the presynaptic beta2 receptors on sympathetic nerve endings and on the adrenomedulla, and accelerate the release of endogenous epinephrine.

Effects of a midazolam-ketamine admixture in human volunteers.

As the ideal sedative does not exist for all situations, we examined the effect of a midazolam-ketamine sedoanalgesic admixture in human volunteers. Ten ASA physical status I volunteers were administered loading doses of 0.07 mg/kg of midazolam followed by 0.7 mg/kg of ketamine. The same amount of midazolam and ketamine was then infused constantly over 1 hour via a 60 drops (gtts)/mL i.v. infusion set. Blood samples were analyzed for plasma catecholamine levels. Respiration rate and oxygen saturation did not alter significantly from baseline levels. Heart rate and systolic blood pressure remained stable with an increase of 15% in heart rate and 6% in systolic blood pressure only at 10 minutes following the bolus loading. Diastolic blood pressure did not alter significantly from baseline levels (P < .05). Plasma catecholamines levels remained stable except for an increase in epinephrine (38%) and norepinephrine (19%) 10 minutes following the bolus injections. Plasma dopamine levels remained unchanged. There were no cases of unpleasant dreaming, dysphoria, or emergence-type reactions. This combined nonnarcotic sedoanalgesic technique maintains spontaneous ventilation and stable cardiorespiratory parameters and may be considered as an alternative to traditional conscious sedation or general anesthesia.

Sedation in Japanese dental schools.

There is very little information about the practice of sedation in Japan. Despite the remarkable advances in dentistry, fear and anxiety continue to be significant deterrents for seeking dental services. Most dental procedures can fortunately be undertaken with the aid of sedation. A comprehensive survey of all the dental schools in Japan was carried out to determine what sedation practices were used in Japan. All 29 dental schools in Japan possessed a dedicated department of anesthesiology at the time of this survey. The survey attempted to determine the specific sedation methods (techniques, routes of administration, and agents used in sedation) as well as practices (monitoring, fasting, location, education, and fees involved in sedation). The results indicate that there was a broad range in sedation practices. The Japanese Dental Society of Anesthesiology may wish to examine the findings of this study and may wish to formulate guidelines appropriate for the practice of sedation in Japan. Others may also wish to compare their own practices with those of Japan.

Usefulness of measuring plasma cytokines in oral and maxillofacial surgery.

We determined the intra- and postoperative plasma concentrations of cytokines (tumor necrosis factor [TNF]-Alpha, interleukin [IL]-1Beta, IL-6, and IL-8) in oral surgery patients with procedures ranging in duration from 20 to 375 min and investigated their relationship to the intensity of the surgical stress over time. No significant differences from baseline levels were observed in the levels of TNF-Alpha, IL-1Beta, and IL-8. By contrast, increased IL-6 levels were noted only on the first postoperative day, when they reached 1500% of the baseline level, after which they decreased to preoperative levels by the third postoperative day and tended to reflect the intensity of surgical stress.

Effects of a propofol--ketamine admixture in human volunteers.

As the ideal sedative does not exist for all situations, particularly in settings with limited resources, the effect of a propofol-ketamine combination in human volunteers was examined. Eleven American Society of Anesthesiologists (ASA) physical status I volunteers were administered propofol at a loading dose of 1 mg/kg and two minutes later by 0.7 mg/kg of ketamine. This was followed by a propofol-ketamine combination of 5 mg/kg of propofol admixed with 0.7 mg/kg of ketamine that was infused over one hour via a 60 gtts/ml intravenous. Infusion set. Cardiorespiratory parameters were recorded and blood samples taken to measure plasma catecholamine levels prior to, during and for thirty minutes following the termination of the infusion. Rate of respiration and oxygen saturation levels did not alter significantly from baseline levels. When there was a cardiovascular decrease from base line levels it was on average 11% for systolic, 15% diastolic blood pressure and 14% for heart rate. Only plasma adrenaline and noradrenaline increased by 28 and 20%, 10 minutes following the bolus injectons. No dysphoria was experienced. This combined sedoanalgesic technique in nonstimulated human volunteers maintains spontaneous ventilation and may be considered as abalanced alternative to traditional conscious sedation or general anesthesia.

BIS monitoring during midazolam and midazolam-ketamine conscious intravenous sedation for oral surgery.

OBJECTIVE: The purpose of this study was to determine whether the bispectral index scale (BIS) would provide added benefit to established methods of monitoring conscious sedation with midazolam (M group) or midazolam supplemented with ketamine (MK group). STUDY DESIGN: BIS was prospectively and blindly examined in 22 patients receiving outpatient oral surgery with conscious sedation supplemented with local anesthesia. RESULTS: The average midazolam dose in the midazolam group over the treatment period was 0.01 mg/kg/h, and the average midazolam plus ketamine dose was 0.01 and 0.05 mg/kg/h, respectively. Mean BIS values throughout the sedation study period were 90 for the midazolam group and 94 for the midazolam plus ketamine group. The addition of ketamine did not lower BIS. BIS values did not alter significantly over time except for an expected transient drop after the midazolam bolus induction. CONCLUSION: BIS levels remained close to baseline levels, suggesting that BIS would not provided any additional benefit to currently established methods of monitoring patient consciousness during conscious sedation for oral surgery.

The relationship of placement accuracy and insertion times for the laryngeal mask airway to the training of inexperienced dental students.

Any health care professional can be faced with a medical emergency in which the patient needs ventilatory support. Bag-valve-mask ventilation with the assistance of an oropharyngeal airway that uses 100% oxygen is currently the preferred method for artificial ventilation. This procedure is generally performed ineffectively by most dentists inexperienced in airway management. We examined whether a short and simple period of training by dental students inexperienced in airway management would increase the speed and accuracy of the placement of the laryngeal mask airway (LMA), which may be a superior airway device to the bag-valve-mask and oropharyngeal airway. Thirty-five dental students inexperienced in airway management were divided into 3 groups. The first group received only a demonstration on how to use the LMA. The second and third groups received the demonstration plus practiced inserting the LMA 5 and 10 times, respectively. A dental anesthesiologist graded the placement of the LMA with a tracheobroncho-fiberscope (fiberoptic bronchoscope). Those who practiced inserting the LMA 5 times faired better than those who received no training; however, those who practiced 10 times did not do any better than the second group. The LMA can be inserted rapidly and effectively by dentists inexperienced in airway management after a short period of simple training that may be critical when personnel experienced in intubation are not readily available.