A careful preoperative history can be helpful in detecting problems with previous anesthetic experiences. However, it has been found that in the patients who have developed a complete syndrome of malignant hyperthermia (MH), 30% had prior uneventful general anesthesia. It is therefore of extreme importance when delivering anesthesia to recognize the signs of MH early in order to initiate correct procedures to prevent the development of a fulminating crisis of MH.
Isoflurane is known to produce slight tachycardia in humans. This study examined the effects of isoflurane on cardiovascular parameters in dogs. Four groups, with six dogs per group, were anesthetized with isoflurane. Prior to isoflurane administration, a femoral artery catheter was inserted. Group 1 was anesthetized with isoflurane alone. Group 2 was pretreated with fentanyl prior to administration of isoflurane. Group 3, anesthetized with isoflurane alone, had a Swan-Ganz catheter introduced through the external jugular vein. Group 4 was pre-treated with fentanyl prior to administration of isoflurane, and had a Swan-Ganz catheter. Physiologic parameters were recorded at 15-min intervals as isoflurane was reduced from 3.5% to 1.5% by 0.5% increments. Heart rate increased while blood pressure decreased during induction (8.5 min) in Group 1 and then returned to control values. In Group 2, heart rate declined with no changes in blood pressure over all isoflurane concentrations. The induction time (time from initiation of the anesthetic until intubation was achieved) was 2 min. In Group 3, the heart rate increased and the blood pressure decreased, with an induction time of 10 min. Cardiac output and pulmonary artery pressure varied inversely to the isoflurane concentration. In Group 4, heart rate decreased with a minimal decrease in blood pressure, and an induction time of 3.5 min. Cardiac output and pulmonary artery pressure varied inversely to the isoflurane concentration. A fifth group of 6 dogs was monitored for heart rate only, while a mask was placed over their noses to simulate the procedure for the administration of an anesthetic. The heart rate increased similar to that of the dogs in Groups 1 and 3, but the tachycardia was abolished with the administration of fentanyl. Increased heart rate could not be directly attributed to isoflurane but was probably due to catecholamines released during induction. Fentanyl blocked this effect, resulting in a decrease in heart rate.
Symptoms of temporomandibular joint pathology are present in a relatively high proportion of the population. Conventional radiographic techniques used to evaluate the morphology of the joint provide data which may be difficult to interpret. These techniques are reviewed briefly and their interpretational shortcomings are noted. Computed tomography is currently being used by some clinicians to evaluate the joint. This technique may also yield data which are difficult to interpret. Extended processing of CT data to provide three-dimensional images of the joint enhances the technique as a means of diagnosing hard tissue pathology, but despite reports in the literature detailing its use in diagnosing soft tissue pathology, CT is not optimal for this purpose. The introduction of nuclear magnetic resonance imaging provides a means of examining the soft tissues of the joint in either two- or three-dimensional images and has the advantage over all previous techniques in that the patient is not subjected to ionizing radiation during the scan process.
Temporomandibular joint; radiographic evaluation; conventional radiography; computed tomography; three dimensional imaging; nuclear magnetic resonance
Patients about to undergo oral surgical procedures may be fearful and anxious. It is thought that stress reduction can be attained by relaxation and reassurance. One time stress reduction techniques were tested on 100 patients prior to oral surgery and measurements of stress were made prior to and during the procedures. Patients were divided randomly into four groups: group one patients received general surgical information about tooth removal; group two patients listened to a relaxation tape; group three patients listened to a combination of surgical information and relaxation information tape; and group four patients had no intervention. The day of oral surgery, patients were administered Corah's Dental Anxiety Scale. In addition, measurements of peripheral skin temperature, frontalis EMG for facial muscle tension and blood pressure recordings were made. The measurements were taken prior to and after the patients listened to the information mentioned above on audio tapes, (groups 1-3) or relaxed in their own way (group 4). Self assessment of anxiety reduction was recorded and evaluation of relaxation was made by the oral surgeon during the surgical procedure. Observations were made relating to age, sex, degree of surgical difficulty and presence or absence of preoperative pain. A significant decrease in blood pressure (p_.01 was noted between the experimental and control group. Reduction of anxiety was notably seen with group three patients, where EMG and temperature differences varied from the control group. It was also noted that all patients perceived some degree of relaxation.
In a double-blind study conducted in 112 patients undergoing removal of four impacted third molar teeth, etidocaine hydrochloride 1.5% solution with epinephrine 1:200,000 and lidocaine hydrochloride 2.0% solution with epinephrine 1:100,000 were used, one on each side of the face, to produce inferior alveolar nerve block, infiltration anesthesia of the maxillary tooth and hemostasis of the mucoperiosteum around each tooth.
Surgically adequate anesthesia was rapidly produced by both agents but the duration of action of etidocaine was longer than that of lidocaine as reflected in more prolonged numbness of the lip and delayed onset of pain. Moreover, after etidocaine treatment fewer patients reported severe pain as the local anesthesia receded. No adverse local or systemic effects were observed in, or reported by, any of the patients.
The time course of recovery following a brief exposure to 50% N2O in O2 was assessed using a standard psychomotor test, a subjective ranking of experimental pain, and somatosensory evoked potential recordings. Results of this study suggest that recovery from a brief N2O exposure may be prolonged and conventional methods of assessing recovery from CNS active drugs like N2O may be inadequate.
This study investigated the frequency of hematoma formation subsequent to injection of dental local anesthetics in 4,134 children, 3 to 13 years of age. Hematoma formation occurred following 0.1% of the injections, all being buccal infiltrations of maxillary molars. This represents a 0.4% incidence of hematoma formation subsequent to this injection. There was no age specificity in hematoma formation, occurring in one 5 year old, one 7 year old, one 8 year old, one 10 year old, and one 11 year old.
General anesthetics, in addition to eliminating the perception of stimuli, profound physiologic effects in other systems including the cardiovascular and respiratory systems. A thorough knowledge of the pharmacodynamics and pharmacokinetics of each agents as well as an understanding of the patient's physiologic reserve will allow the anesthetist to reasonably predict the response to a given drug. The ability to forecast patient responses imparts control over an anesthetic technique which contributes to the overall safety of the procesure. This paper reviews pharmacodynamics of general anesthetic agents commonly used in dentistry
Abnormal electroencephalographic seizure-like activity and myoclonic movements have been recognized during enflurane anesthesia. This is most commonly seen in the presence of respiratory alkalosis and high concentrations of enflurane. Immediate and delayed postoperative generalized tonic-clonic convulsions have also been reported after enflurane anesthesia. Experimental studies have shown that auditory stimuli could facilitate seizure activity during deep enflurane anesthesia. Here we report a case of intraoperative generalized tonic-clonic convulsion during low concentrations of enflurane without evidence of hyperventilation and the presence of auditory stimulation.
In order to establish a protocol for the anesthetic management of patients undergoing lithium therapy, one must consider the mechanisms of lithium action. Many proposals for different mechanisms appear in the literature which attempt to explain the pharmacology, physiology, metabolism, administration, dosage and adverse effects of lithium. This paper reviews the pertinent scientific and clinical information to enable the anesthesiologist to rationally administer anesthesia to patients on a lithium regimen.
Plasma beta-endorphin, pain and anxiety were measured in patients before, during, and 1 and 3 hours following oral surgery. Diazepam and fentanyl blocked the stress induced increase in plasma beta-endorphin experienced by patients administered placebo. Moreover, intra-operative anxiety and post-operative pain appear to constitute independent and possibly equipotent stimuli for release of pituitary beta-endorphin in humans.