Recovery after intravenous sedation. A comparison of clinical and paper and pencil tests used in assessing late effects of diazepam

Diazepam Tolerance Effects on Vestibular Function Testing, Part II: Vestibulo-Ocular Reflex Parameters during Rotational Testing

Objectives:

The purpose of this prospective study was to determine whether clinical doses of diazepam (DZ; 10 mg/d) administered for 14 days result in tolerance as measured by the sinuosidal harmonic acceleration (SHA) rotational test. It has been shown that repeated dosing with DZ leads to accumulation and tolerance in outcome measures that assess memory, sedation, and psychomotor tasks.

Methods:

In a double-blinded, repeated-measures design, 30 normal male subjects who ranged in age from 20 to 36 years were randomly assigned to a placebo group or a DZ group and participated in 6 SHA rotational sessions over a 2-week period. Analysis of drug-placebo differences in percent change from baseline was performed with a 1-way analysis of variance.

Results:

Vestibulo-ocular reflex gain and phase frequencies at 0.01, 0.02, 0.04, and 0.08 Hz were significant (p < .05) for treatment group. No significant effect was observed for gain and phase frequency at 0.16 Hz — a finding that indicates selective effects on different central nervous system mechanisms. There was no statistical significance for time.

Conclusions:

Clinically, the DZ subjects' scores remained within the normal ranges for vestibulo-ocular phase and gain, suggesting that patients in whom drug cessation is problematic may not have to discontinue DZ before testing with the SHA rotational system.

Correlation between precise and simple tests in recovery of dynamic balance function after intravenous sedation with midazolam in the elderly

PURPOSE

Assessing the recovery of dynamic balance after intravenous sedation in the elderly is important for ensuring their safe discharge, especially when they are walking. A reliable, simple dynamic balance test would be useful in daily clinical practice. We observed the recovery of balance after intravenous sedation with midazolam, using computerized dynamic posturography (CDP), and we evaluated the correlation between the CDP result and the results of simple dynamic balance tests.

METHODS

Midazolam was administered in divided doses, until the Wilson sedation score reached 3, in 18 elderly male volunteers. The dynamic balance test using CDP with perturbation stimuli was performed before and after sedation. As simple dynamic balance tests, the usual-speed walking (USW) and maximum-speed walking (MSW) tests and a modified timed "up and go" (TUG) test (subjects stand up from a chair, walk 5 m forward and return to the chair with MSW, and sit down again) were performed.

RESULTS

The recovery times (defined as the time until the significant difference between the value at each time point and the baseline value disappeared) in the dynamic balance test (CDP), USW test, MSW test, and TUG test, were 80, 40, 80, 80 min, respectively. There was a significant, strong positive correlation between the result of the dynamic balance test (CDP) and the TUG test (P < 0.01; r = 0.70).

CONCLUSION

The TUG test is a useful simple dynamic balance/motor test that can be used in daily clinical practice in the elderly.

Recovery of dynamic balance after additional small divided doses of midazolam given intravenously for sedation

We have previously reported that a dynamic balance test with perturbation stimuli and computerised dynamic posturography sensitively reflected the inhibitory effect on balance of intravenous midazolam sedation given intravenously as a single dose, and recovery time was within 80 min. The purpose of this study was to investigate the recovery of dynamic balance after additional doses of midazolam. Eighteen young adult male volunteers were sedated with midazolam given intravenously. The initial dose was given until the Wilson sedation score reached 3, and an additional dose was given until the same score was obtained 40 min later. They were tested with perturbation stimuli 40, 80, 100, and 120 min after the additional doses had been given. Their recovery time was recorded. The mean (S.D.) initial dose of midazolam was 0.07 (0.005) mg kg(-1), and additional doses were 41 (7)% of the initial dose. The serial changes in bispectral index after initial and additional doses were similar. The recovery time for the dynamic balance test (within 80 min) was the same as that recorded in the previous single-dose study. The recovery time of the psychomotor function test was within 75 min. Additional doses of midazolam aiming for a Wilson sedation score of 3 at a dose about 40% of the initial dose and given 40 min after the initial dose are valid in terms of the maintenance of sedation and recovery of dynamic balance. Complete recovery time, including psychomotor function, was within 80 min of the additional dose of the drug.

Methohexital infusion technique for conscious sedation

PURPOSE

The purpose of this study was to evaluate a methohexital infusion technique for conscious sedation in oral surgical procedures. Patients were evaluated for recall, comfort, recovery, and surgeon's estimate of cooperation.

MATERIALS AND METHODS

Twenty adult (mean age, 29 years) ASA I or II patients requiring various dentoalveolar procedures were entered into the study. Administration of 1.5 micrograms/kg fentanyl and 1 mg midazolam were given until sedation was achieved. An infusion of methohexital was started using 50 micrograms/kg/min and increased as needed to 75 micrograms/kg/min. Postoperatively, visual analog scales were used to evaluate the efficacy of the technique.

RESULTS

The average total amount of methohexital infused was 257 mg for an average surgical time of 88 minutes. Recovery times were short and uneventful. Patients were cleared for discharge in under 35 minutes. No cardiac or respiratory side effects were noted other than a mild increase ( < 15%) in heart rate. Shivering and hiccoughing were noted in two and four cases, respectively. Recall of surgical events reported by patients was low and patient cooperation was high as reported by surgeons.

CONCLUSION

The continuous infusion of methohexital for conscious sedation has been shown to be safe, effective, inexpensive, and well accepted by patients and surgeons.

Postural control after propofol anaesthesia in minor surgery

There is, not only from an economic perspective, a continuous search for surgical and anaesthetic procedures that allow out-patient surgery to be conducted. Reliable estimators of the patient's street fitness are of the utmost importance. Balancing capacity is one aspect that should be considered. Clinical methods like Romberg's are subjective and imprecise. Dynamic posturography comprises a movable support surface and visual surround that are either stable or referenced to the patient's sway, with eyes open or closed. In this study the recovery from propofol anaesthesia was studied in 8 patients who underwent surgery for minor microlaryngoscopic procedures. Dynamic posturography who performed before, and 2 and 4 h after cessation of anaesthesia. All patients who were awake had normal balancing ability already at 2 h after anaesthesia. Further studies may supply additional information of other aspects of discharge after anaesthesia.

Choice reaction time as a measure of recovery from general anesthesia

The purpose of the study was to evaluate the reliability and validity of choice reaction time as a measure of recovery from general anesthesia. An experimental group of 43 patients underwent surgery under general anesthesia; they were measured before anesthesia and also 90, 150 and 210 min. after the end of anesthesia. A control group of 38 underwent the same procedure. Choice reaction time was not a valid measure of recovery from general anesthesia since the test was not reliable.

Residual psychomotor effects following reversal of midazolam sedation with flumazenil

The ability of flumazenil to reverse the effects of midazolam sedation was examined in a randomised, crossover, placebo controlled study in six male volunteers. Subjects received intravenous injections of either (a) midazolam 10 mg followed 10 minutes later by flumazenil 1.0 mg or (b) midazolam 10 mg followed after 10 minutes by flumazenil 4 mg or (c) placebo followed after 10 minutes by placebo. Post reversal drug effects were examined using a psychomotor battery (critical flicker fusion, digit symbol substitution, tapping test, ball-bearing test, number recall, reflex time) and linear analogue mood scales. It was found that a residual psychomotor deficit was present following flumazenil and that this persisted for up to 125 minutes after the 1.0 mg dose and 65 minutes following 4 mg. A small deterioration in performance was apparent after initial reversal with 1.0 mg, the peak deterioration occurring at 35 minutes.

Sedation for fibreoptic bronchoscopy: comparison of alfentanil with papaveretum and diazepam

Sedation for fibreoptic bronchoscopy should produce optimal conditions for the operator, patient comfort and rapid recovery allowing early discharge home. We have compared a regimen producing 'light' sedation with a more traditional regimen producing 'deep' sedation. Seventy-six patients undergoing fibreoptic bronchoscopy under topical anaesthesia were randomized to receive either light sedation with the short acting opiate, alfentanil (median dose 1.1 mg, range 0.5-2.6 mg) or deep sedation with a combination of papaveretum (median dose 10 mg, range 5-15 mg) and diazepam (median dose 8 mg, range 0-20 mg). Both techniques gave equally good operating conditions, although patients given alfentanil coughed less than those given papaveretum and diazepam (U = 2.814 P less than 0.01). Patients recorded their degree of apprehension on a visual analogue scale prior to sedation and the actual degree of comfort experienced after recovery. There was no significant difference between apprehension or comfort between the groups. This was despite a higher degree of amnesia for an irrelevant object shown during the bronchoscopy in the deeply sedated group (chi 2 = 21.084 P less than 0.001). Patients given alfentanil performed significantly better in a modified Romberg test (chi 2 = 4.357 P less than 0.05) and a visualisation test (t = 3.035 P less than 0.01) two hours after the bronchoscopy. Alfentanil produced good operating conditions, patient comfort, less cough and a more rapid recovery, compared to the deep sedation regimen, and is an ideal sedative for fibreoptic bronchoscopy.

Influence of auditory or visual warning on visual reaction time with variations of subjects' alertness

The purpose of the study was to determine the effect of visual and auditory warning on visual reaction time with variations of subjects' alertness. An experimental group of 30 subjects was tested with an auditory or visual warning signal; foreperiods lasted 3, 2, and 4 sec. Reaction time was shorter as alertness improved and with an auditory warning signal. Comparable measures in a control group showed that visual reaction time was shorter when an auditory warning signal was used.

A comparison between isoflurane and alfentanil supplemented anaesthesia for short procedures

Sixty unpremedicated patients undergoing short urological and gynaecological procedures were randomly allocated to three groups to receive either methohexitone, alfentanil, nitrous oxide and oxygen, methohexitone, isoflurane and oxygen or methohexitone, isoflurane, nitrous oxide and oxygen. The group receiving methohexitone, isoflurane and oxygen was abandoned after 11 patients had been studied, due to poor conditions during induction of anaesthesia. Therefore, data from only 51 patients are presented. Early recovery was assessed by time to opening eyes, giving correct name and date of birth; later, recovery was assessed by using the postbox test and deletion of 'p's. During anaesthesia and surgery, there was a high incidence of coughing and laryngospasm in the isoflurane groups. The patients in the alfentanil group opened their eyes and gave their names and dates of birth significantly faster postoperatively (p less than 0.01) than those in the isoflurane groups. However, there were no significant differences between the three groups regarding the later tests of recovery. The late recovery after isoflurane was equal to that obtained using an intravenous technique with alfentanil, although the peroperative complication rate was higher.

Midazolam and diazepam compared as sedatives for outpatient surgery under local analgesia

Patients who had given their informed consent took part in a study to compare the sedative properties of the new benzodiazepine, midazolam, with diazepam. The drugs were administered intravenously and the quality of sedation, profoundness of amnesia, and rate of recovery were examined. Both drugs provided good-quality sedation, with midazolam producing a significantly greater degree of amnesia. Psychomotor tests used to assess recovery showed that patient performance following exposure to either drug had returned to normal 2 hours postsedation. However, patients who had received diazepam were drowsier later in the day and during the night following sedation than those who received midazolam. The implications of these findings are discussed.

Clinical assessment of new I.V. sedation agents and techniques

The purpose of this paper has been to describe the information that must be gathered before a new drug can be used effectively and safely for I.V. sedation. A new drug, midazolam, has been used as an illustrative example.

Clinical effectiveness and untoward effects of new agents and techniques used in intravenous sedation

An ideal i.v. sedative for dentistry should provide anti-anxiety and analgesic activity, amnesic action, and patient cooperation without depression of the cardiorespiratory system and with rapid recovery. Lorazepam does not provide any advantages over the currently available agents, but midazolam, a new water-soluble benzodiazepine, and later selective benzodiazepine receptor antagonists may play an important role in outpatient sedation.

Recovery after general anaesthesia for laparoscopy

Recovery after two methods of light general anaesthesia for gynaecological laparoscopy was studied. For this purpose, 30 patients were divided into two equal groups (A and B). The patients in group A were anaesthetized with thiopentone, fentanyl and suxamethonium infusion, while the patients in group B received inhalation anaesthesia with enflurane and suxamethonium infusion. Both groups were normoventilated with nitrous-oxide and oxygen mixture. A battery of recovery tests was applied in the recovery room. The patients who received inhalation anaesthesia with enflurane scored better in the recovery tests, and reached preoperative values after 3 h in the recovery room. Inhalation anaesthesia with enflurane was accepted well by the patients and provided good working conditions for the surgeons. It is suitable for outpatient gynaecological laparoscopy because it ensures rapid recovery.

The modified GATB (M) as a measure of recovery from general anesthesia

23 patients were evaluated following surgery under general anesthesia with enflurane or halothane. Data on the M tests of the modified GATB gave significant differences 1 ½, 2 ½, and 3 ½ hr. after the end of the period of anesthesia when compared with the baseline. The performance of a control group shows lack of reliability of this form of the test.

A clinical neuropsychological study of the postoperative course after three types of anaesthesia

In a double-blind study, 57 patients were anaesthetized with either Althesin, thiopentone, or fentanyl combined with diazepam for cystoscopies. One and a half and four hours after the administration of anaesthesia, the patients were investigated with an objective neuropsychological method, continuous Reaction Time, and with a subjective rating scale. Beecher's Mood Scale. One week later the patients answered a questionnaire about side-effects experienced during the days following anaesthesia. At the 1 1/2 h investigation, the patients were cerebrally affected, both subjectively and objectively. The CNS-dysfunction was different for the three anaesthetics. After administration of thiopentone, the patients experienced the highest degree of subjective effects but had the smallest reaction time prolongation. Fentanyl-diazepam gave the least subjective effects, but the highest degree of cerebral affection in the reaction time measurements. The effects of Althesin were intermediate. Four hours after anaesthesia, the reaction time prolongations had disappeared, except for Althesin, and only patients who had thiopentone registered subjective effects. The number of side-effects was greatest and most prolonged following thiopentone. About 25% of the patients reported that side-effects had persisted more than 1 day after anaesthesia.

Anaesthesia and cognitive functioning. Mental function in postoperative day patients at the time of their release

Day care patients at Law Hospital, who had received either a general or a local anaesthetic in conjunction with minor surgery, were assessed by five tests of mental function before surgery and before discharge from hospital some hours after surgery. These patients did not perform differently from control patients, who were subjected to the same two testing sessions, without intervening surgery or anaesthesia. It was concluded that the day cases were quite capable of normal cognitive functioning at the time of their discharge and that the procedures followed by the hospital for the discharge of day cases are generally adequate.

Diazepam and lorazepam compared as sedatives for outpatient third molar surgery

A clinical trial was designed to compare diazepam and lorazepam when administered intravenously immediately prior to third molar surgery. The two drugs were compared on three scores, patient behaviour during surgery, presence of amnesia and extent of psychomotor impairment. Within the confines of the investigation the principle difference between diazepam and lorazepam was the greater degree of psychomotor impairment induced by the latter drug two hours post-injection.

Day case anaesthesia and memory

Two simple anaesthetic techniques were administered to forty healthy women undergoing minor gynaecological surgery. There was a significantly shorter immediate recovery period following the use of a fentanyl and methohexitone technique. Memory function testing revealed an impairment of the ability to retain new information following anaesthesia. This returned to normal within 3 hr.

Effect of pain on human psychomotor performance

The effect of pain on human psychomotor performance was measured in seven healthy volunteers after an intramuscular injection of vitamin B or saline using a controlled cross-over method. Vitamin B, causing moderate to severe pain, or painless saline was injected into the buttock at a time when the subjects' performance was impaired after an intravenous injection of diazepam (0.3 mg/kg). The subjects' psychomotor performance was tested before and 2, 3, and 4 h after diazepam (before, 15 min, and 1 h 15 min after the vitamin B and saline injections). The effects of the vitamin B injection on the subjects' divided attention, reaction or co-ordination skills or their ability to discriminate the fusion of flickering light did not differ from the corresponding effects of the saline injection. The results suggest that pain as such does not have any major influence on human psychomotor performance.

Operating room nurses' psychomotor and driving skills after occupational exposure to halothane and nitrous oxide

Concentrations of halothane and nitrous oxide were assayed by gas chromatography throughout a working day in three operating theatres and in the end-tidal air of 19 nurses 15 and 60 min after leaving the theatres. Perceptual, psychomotor and driving skills were measured in these nurses and in 11 younger nurses working in the wards of the same hospital. A complicated psychomotor test battery and a driving simulator were used. End-tidal air concentrations of halothane and nitrous oxide were positively correlated with the exposure level of these gases in the operating theatres. Some of the operating room nurses had greater amounts of halothane in their end-tidal air (average 15 to 10 ppm) than student volunteers 4.5 h after 3.5 min of general anaesthesia with a combination of halothanenitrous-oxide oxygen (10 ppm halothane). These volunteers had worse psychomotor and driving performances when measured than controls who had not been anaesthetized. No correlations were found between the concentrations of halothane or nitrous oxide in end-tidal air and psychomotor or driving performance. Despite their higher age and exposure to the operating room environment, the driving skills of the operating room nurses were similar to those of the ward nurses. The results suggest that tolerance to anaesthetic gases develops among operating room personnel. No impairment of driving skills can be expected after daily exposure to halothan and nitrous oxide among long-term employees in operating theatres.

Amnesic action of and skills related to driving after intravenous flunitrazepam

Amnesic action, skills related to driving and the ability to discriminate the fusion of flickering light were measured double-blind in 29 healthy volunteers before and after three doses of intravenous flunitrazepam. Every subject experienced amnesia for the pinching of the abdomen after being injected with flunitrazepam. Even the smallest dose of flunitrazepam (0.01 mg/kg) caused the amnesia without affecting the level of consciousness. The late effects of flunitrazepam were the most harmful to coordination. With 0.01 mg/kg eye-hand coordination was slightly impaired for as long as 6 h after the injection, and after 0.02 and 0.03 mg/kg the impairment was still significant (P less than 0.05) at the last observation period 10 h after the injection. It was concluded that, because the amnesic action of flunitrazepam is more effective than that of clinically comparable doses of diazepam, further clinical experiments with flunitrazepam are warranted. Its longer and more harmful effects on psychomotor performance than those of equipotent doses of diazepam suggest that doses of 0.02 mg/kg or more of flunitrazepam should be avoided in outpatient anaesthesia or sedation.