Peggy R. Wirdzek

Effects of diazepam premedication and epinephrine-containing local anesthetic on cardiovascular and plasma catecholamine responses to oral surgery

The effects of diazepam premedication and administration of an epinephrine-containing local anesthetic on plasma catecholamine levels and cardiovascular parameters were evaluated prior to and during a minor surgical procedure, the removal of impacted third molars. Significant elevations in circulating epinephrine levels (203% above control) and cardiac output (30%) were seen in unsedated patients after administration of lidocaine with epinephrine before surgery, while no changes were seen after lidocaine alone. Unsedated patients had increased norepinephrine (24%) and epinephrine (57%) levels during surgery. Diazepam premedication decreased norepinephrine levels 29% below preoperative levels, followed by an increase during surgery to preoperative levels. These results indicate that intraoral injections of epinephrine-containing local anesthetics result in increased circulating epinephrine levels that are associated with cardiovascular changes and that diazepam premedication decreases plasma norepinephrine levels and attenuates the sympathoadrenal response to surgical stress.

Abnormal and collateral innervations of sympathetic and peripheral sensory fields associated with a case of causalgia

&NA; A 41‐year‐old female developed spontaneous burning pain (causalgia) and stimulus‐induced dysesthesia (allodynia) of the dorso‐lateral part of her right foot following trauma. An L3 and L4 sympathectomy eliminated the spontaneous burning pain for only 1 year, but did not affect the stimulus‐induced dysesthesia. We evaluated her two years post‐sympathectomy with grouped sequential anesthetic blocks and sensory testing. Sympathetic blocks at L1 and L2 eliminated the burning pain and normalized heat perception from baseline hyperalgesia, indicating that the causalgia had been reactivated via more rostral sympathetic ganglia. Anesthetic block of the sural nerve eliminated both the burning pain and the stimulus‐induced dysesthesia. During the sural nerve block, perception of touch and pin, but not heat, was preserved in the sural distribution. All perception was lost following subsequent block of the peroneal branches. When the peroneals were blocked first, perception of touch, pin and heat remained in the sural distribution. With peroneal block the burning pain was eliminated, but the stimulus‐induced dysesthesia remained, even in the anesthetic peroneal territory. When sural block was added to the peroneal block the stimulus‐induced dysesthesia was eliminated, and sensation in the sural distribution was lost. We conclude that the sural distribution received overalapping innervation for touch and pin‐prick perception, but that heat perception, burning pain and the stimulus‐induced dysesthesia were sural nerve dependent. Further, we were able to dissociate causalgia pain from allodynia in this patient.

Evaluation of etidocaine hydrochloride for local anesthesia and postoperative pain control in oral surgery

Etidocaine hydrochloride, an amide-type local anesthetic with prolonged duration of action, was evaluated and compared with a standard local anesthetic, lidocaine, to determine its efficacy as a local anesthetic and its effect on postoperative pain following removal of impacted third molars. The findings indicate that 1.5% etidocaine hydrochloride with 1:200,000 epinephrine, in comparison with 2% lidocaine hydrochloride with 1:100,000 epinephrine, suppresses the magnitude of postoperative pain, and results in anesthesia comparable with that obtained by lidocaine, but results in greater blood loss during surgery.

Recovery following intravenous sedation during dental surgery performed under local anesthesia.

Recovery of psychomotor and perceptual performance from two combinations of intravenous sedatives was assessed in 124 oral surgical patients undergoing third molar extractions under local infiltration anesthesia. Ninety-four patients in the experimental group received 15 mg of diazepam and 20 to 200 mg of methohexital intravenously on one occasion and 12.5 mg of diazepam, 20 to 200 mg of methohexital, and 0.1 mg of fentanyl intravenously on another occasion in a randomized, crossover design. Thirty patients in the control group received saline placebo intravenously during a single surgery. Both drug combinations produced significantly prolonged decrements in performance in comparison to placebo. Reduction in the diazepam dose from 15 to 12.5 mg and the addition of fentanyl, a short-acting narcotic, produced greater sedation without prolonging recovery. Psychomotor function recovered to preoperative levels before perceptual performance. These results show that postsurgical deficits in psychomotor and perceptual function result from the sedative drugs and not from the effects of local anesthetics or physiologic and psychological responses to surgery. These results also suggest that psychomotor tests are inappropriate measures of recovery and that superior sedation with rapid recovery may be achieved with reduced doses of longer acting agents such as diazepam and with the addition of shorter acting agents that do not prolong recovery.

Evaluation by thoracic impedance cardiography of diazepam, placebo, and two drug combinations for intravenous sedation of dental outpatients

The cardiovascular and respiratory effects of three common intravenous premedicants were examined noninvasively in a population of 20 dental outpatients scheduled for surgical removal of third-molars. Two third molars from one side of the mouth were removed at each appointment. Group 1 received a diazepam titration (mean dose = 25.6 mgs) at one appointment and placebo at the other appointment. Group 2 received a combination of diazepam (12.5 mg), fentanyl (0.1 mg), and methohexital (mean dose = 18.0 mg) at one appointment and the combination of diazepam (15.0 mg) and methohexital (mean dose = 27.0 mg) at the other appointment. Noninvasive measurement of cardiac output revealed little change during intravenous drug administration, but a significant increase was seen in all groups following local anesthesia and during surgery. Heart rate was elevated and stroke volume decreased during administration of the two-drug combinations. Oxygen saturation was greatly decreased following the combination of diazepam, fentanyl, and methohexital. These findings indicate that the combination of diazepam, fentanyl, and methohexital results in decreased oxygen saturation, a transient decrease in stroke volume, and an elevated heart rate when used as an intravenous premedicant for dental outpatients.