Anaesthetic premedication: aims, assessment and methods

Preanaesthetic Medication: A Survey of Current Usage

A survey has been carried out amongst the UK based members of the Association of Anaesthetists of Great Britain and Ireland regarding their practice of premedication. Ninety-three per cent of respondents (reply rate 51.7%) used sedative-hypnotic premedication routinely in adults and 84% in children. However, anticholinergic premedication was used by only 36% in adults and 56% in children. Temazepam was the most frequently used sedative premedicant in adults and trimeprazine in children. Atropine and hyoscine were the most frequently used anticholinergic drugs. The main reasons for using sedative-hypnotic premedication were allaying anxiety and providing sedation. The main reasons for using anticholinergic drugs were drying of secretions and protection against vagal overactivity. This survey concludes that while sedative-hypnotic premedication continues to be used in the majority of patients with oral benzodiazepines the most frequently used drugs, the use of anticholinergic premedication continues to decline.

Comparison of preanesthetic sedation in pediatric patients with oral and intranasal midazolam

BACKGROUND AND AIMS

Preoperative anxiety in children leading to postoperative negative changes and long-term behavioral problems needs better preanesthetic sedation. Across the world, midazolam is the most commonly used premedicant in pediatric patients. The fact that no single route has achieved universal acceptance for its administration suggests that each route has its own merits and demerits. This study compares oral midazolam syrup and intranasal midazolam spray as painless and needleless systems of drug administration for preanesthetic sedation in children.

MATERIAL AND METHODS

With randomization, Group O (30 children): Received oral midazolam syrup 0.5 mg/kg and Group IN (30 children): Received intranasal midazolam spray 0.2 mg/kg. Every child was observed for acceptance of drug, response to drug administration, sedation scale, separation score, acceptance to mask, recovery score and side effects of drug. Data were analyzed using Student's t-test, standard error of the difference between two means and Chi-square test.

RESULTS

In Group O and IN, 15/30 children (50%) and 7/30 children (23%) accepted drug easily (P < 0.05); 4/22 children (18%) in Group O and 11/20 children (55%) in Group IN cried after drug administration (P < 0.05). In both the groups, sedation at 20 min after premedication (Group O [80%] 24/30 vs. Group IN [77%] 23/30), parental separation and acceptance to mask were comparable (P > 0.05); 12/30 children (40%) in Group IN showed transient nasal irritation.

CONCLUSION

Oral midazolam and intranasal midazolam spray produce similar anxiolysis and sedation, but acceptance of drug and response to drug administration is better with oral route.

A comparison of intranasal ketamine and intranasal midazolam for pediatric premedication

AIMS AND OBJECTIVES

The aim of our study is to compare the efficacy and side-effects of Ketamine and Midazolam administered nasally for the pediatric premedication.

MATERIALS AND METHODS

We studied 100 American Society of Anesthesiology I and II children aged from 1 to 10 years undergoing various surgical procedures. Totally, 50 children were evaluated for nasal ketamine (using 50 mg/ml vials) at the dose of 5 mg/kg and the other 50 received nasal midazolam 0.2 mg/kg, before induction in operation theater each patient was observed for onset of sedation, degree of sedation, emotional status being recorded with a five point sedation scale, response to venipuncture and acceptance of mask, whether readily, with persuasion or refuse.

RESULTS

The two groups were homogenous. Midazolam showed a statistically significant early onset of sedation (10.76 ± 2.0352 vs. 16.42 ± 2.0696 min). There were no significant differences in venipuncture score, sedation scale at 20 min, acceptance of mask and oxygen saturation throughout the study. Significant tachycardia and 'secretions were observed in the ketamine group intra operatively. Postoperatively emergence (8% vs. 0%) and secretions (28% vs. 4%) were significant in the ketamine group. Nausea and vomiting occurred in l6% versus 10% for midazolam and ketamine group.

CONCLUSIONS

Both midazolam and ketamine nasally are an effective pediatric premedication. Midazolam has an early onset of sedation and is associated with fewer side-effects.

Anesthetic premedication: new horizons of an old practice

The practice of anesthetic premedication embarked upon soon after ether and chloroform were introduced as general anesthetics in the middle of the 19(th) century. By applying opioids and anticholinergics before surgery, the surgical patients could achieve a less anxious state, and more importantly, they would acquire a smoother course during the tedious and dangerous induction stage. Premedication with opioids and anticholinergics was not a routine practice in the 20(th) century when intravenous anesthetics were primarily used as induction agents that significantly shorten the induction time. The current practice of anesthetic premedication has evolved into a generalized scheme that incorporates several aspects of patient care: decreasing preoperative anxiety, dampening intraoperative noxious stimulus and its associated neuroendocrinological changes, and minimizing postoperative adverse effects of anesthesia and surgery. Rational use of premedication in modern anesthesia practice should be justified by individual needs, the types of surgery, and the anesthetic agents and techniques used. In this article, we will provide our readers with updated information about premedication of surgical patients with a focus on the recent application of second generation serotonin type 3 antagonist, antidepressants, and anticonvulsants.

The relationship between salivary biomarkers and state-trait anxiety inventory score under mental arithmetic stress: a pilot study

Measurement of stress hormones is a common objective method for assessment of mental stress. However, the stress of blood sampling alone may also increase stress hormone levels. In the present study, we sampled salivary biomarkers from healthy volunteers under noninvasive conditions and determined their efficacy to assess mental stress. Specifically, we examined the relationship between State Anxiety Inventory score (STAI-s) in subjects exposed to arithmetic stress and salivary chromogranin-A, alpha-amylase, or cortisol. The STAI-s was significantly correlated to salivary alpha-amylase (r = 0.589; P < 0.01) but not to salivary chromogranin-A or cortisol. Therefore, salivary alpha-amylase is a useful indicator of psychosocial stress.

Review of benzodiazepine use in children and adolescents

Clinically, benzodiazepines are used in adult populations much more frequently than in children and adolescents. There may be a number of reasons for this disparity including a dearth of well controlled clinical studies and the issue of dependence associated with long term use. However, over a ten year span there has been nearly a three fold increase in the use patterns for these agents in the child population. In open studies much of the literature has indicated potentially useful results, but these findings have not been replicated when more refined methodological studies have been conducted. The lack of encouraging results in these later studies may be attributable to a number of factors such as modest sample sizes and less than optimal patient selection. Nonetheless, with increasing prescriptions being written for these agents it is not clear what is compelling clinicians to use them. In this paper we will review the available literature on benzodiazepine use in the child and adolescent population, focusing primarily on psychiatric applications.

Preoperative anxiolysis with minimal sedation in elderly patients: bromazepam or clorazepate-dipotassium?

BACKGROUND

In elderly patients undergoing ophthalmic surgery the loss of co-operation due to over-sedation, induced by drugs given preoperatively, may jeopardise the success of microsurgery performed under regional anaesthesia. The aim of this study was to compare the psychotropic effects of bromazepam and clorazepate-dipotassium, two benzodiazepines with predominantly anxiolytic and only weak sedative action.

METHODS

A randomised, placebo-controlled, double-blind study was designed to include 60 patients, ASA physical status II-III, older than 60 years scheduled for ophthalmic surgery under regional anaesthesia. The patients were randomised to receive either bromazepam (3 mg) or clorazepate-dipotassium (20 mg) or placebo. The study drugs were given at 10 p.m. the night before surgery and 90 min before surgery. Using the State-Trait Anxiety Inventory (STAI), the patient's anxiety was assessed at the end of the preoperative visit, on the next morning before the study drug was given and on arrival at the operating theatre.

RESULTS

Bromazepam induced a marked anxiolytic effect as documented by a significant reduction in the STAI State values after both applications (P<0.01). Clorazepate did not differ from placebo at any evaluation time with regard to the STAI and haemodynamic values. Sedative effects and oxygen saturation (SpO2) were comparable in all groups.

CONCLUSION

Bromazepam is superior to clorazepate in its anxiolytic action and suitable as preoperative medication in the elderly patient because of lack of overt sedative effects.

Pharmacological premedication for anaesthesia

The psychological component of preoperative preparation should be completed with a selective use of drugs. The days of poly-pharmacy are over. Heavily sedated patients coming to the operation room with minimal oral secretions are not the purpose of modern premedication. Anxiolysis and slight sedation (painless patients) and analgesia (patients suffering from pain) are the main goals. Anticholinergics should be used only when needed, as is the case with premedication generally. The use of antiemetics and that of agents given for prophylaxis against allergic reactions or aspiration pneumonitis depend on specific needs of the patient. More accurate and generally accepted but simple methods are needed in studying the effects of different premedicants. The present results produced with a huge number of different more or less validated assessments can seldom be compared with each other.

Sublingual triazolam versus peroral diazepam as a premedication for general anaesthesia

Sublingual triazolam 0.2 mg (T) was compared with peroral diazepam 10 mg (D) as a premedicant in a randomised, double-blind study. Eighty-one ASA I-III patients aged 18-70 yr, scheduled for elective surgery and general anaesthesia were studied. The patients were premedicated about one hour preoperatively. The T-group subjects (n = 41) received triazolam sl after a placebo po and the D-group subjects (n = 40) diazepam po before a sl placebo. Anxiety and sedation were evaluated before premedication, every 15 min after that until the patient was removed to the operating room, just before the induction of anaesthesia and both 30 and 60 min after operation. Anxiety and sedation were evaluated by the patient using a visual analogue scale (VAS) and by the anaesthetist with a scale of 0-3 for anxiety and 0-4 for sedation. The patients' experience with regards to their premedication and visit to the operating unit were investigated after the operation. In both groups sedation and anxiolysis became different at 30-45 min after premedication, but at the time just before the induction of anaesthesia there was sedation and anxiolysis only in the T-group. There was no difference between the groups at any time. The T-group patients were more satisfied with their premedication and visit to the operating unit. The study drugs did not cause any cardiorespiratory or other side effects. We conclude that triazolam 0.2 mg sl is at least as effective a premedication as diazepam 10 mg po, that is suitable for patients that cannot swallow, and that the patients were more satisfied with it than with diazepam.

Oral premedication one hour before minor gynaecological surgery--does it have any effect? A comparison between ketobemidone, lorazepam, propranolol and placebo

The purpose of the present study was to compare the effects of oral premedication with ketobemidone 5 mg, lorazepam 1 mg, propranolol 40 mg or placebo, given about an hour prior to anaesthesia, in a prospective randomized double-blind fashion. One hundred and twenty ASA I female patients scheduled for elective laparoscopy were randomly prescribed one of the study drugs. Patient evaluation of anxiety, nurse evaluation of premedication, induction and postoperative course were studied. Ninety-three of the 120 patients (78%) experienced no change or a decrease in anxiety, regardless of type of active drug or placebo administered. Eighty-eight of the patients (73%) were considered adequately premedicated by the nurse observer, with no differences between the groups. Pre induction pulse rate, blood pressure and amount of induction agent needed was also similar between the four groups of patients. No major differences could be seen during the postoperative course. We found no major effects of any of the active drugs studied compared to placebo. Routine use of small doses of oral premedication one hour before elective surgery among low anxiety patients could probably be omitted.

Effect of extradural anaesthesia on the ventilatory response to hypoxaemia

The effect of lumbar or thoracic extradural anaesthesia on the ventilatory response to progressive isocapnic hypoxaemia was studied in two groups of 10 unpremedicated patients. The ventilatory measurements were taken twice, before and 20 min after the administration of 10 ml of lignocaine 2%. Lumbar extradural anaesthesia did not change the slope of the hypoxic response curve, but it significantly increased minute ventilation by 27% at an arterial oxygen saturation of 90%. Thoracic extradural anaesthesia was not associated with any changes in either index. We conclude that neither lumbar nor thoracic extradural anaesthesia impairs the ventilatory response to progressive isocapnic hypoxaemia.

Nasal ketamine for paediatric premedication

Ketamine in a dose of 6 mg.kg-1 was nasally administered in 86 healthy children (ASA I and II), aged from two to five years undergoing elective general, urological or plastic surgery, 20 to 40 min before the scheduled surgery time. These children were compared with 62 others, also aged from two to five years, in whom promethazine and meperidine, 1 mg.kg-1 of each, were injected im. Sedation was started as excellent in 48 and as adequate in 19 children in the ketamine group, compared with nine and 12 respectively in Group 2 (P < 0.05), while salivation was similar in both groups. We conclude that nasal ketamine is an alternative to im preanaesthetic sedation administration in children aged from two to five years.

Oral benzodiazepines and conscious sedation: A review

A large number of benzodiazepines have been studied for use as sedatives and for their anxiolytic potential as premedicants for outpatient surgery. Potent, new, orally-administered drugs with short half-lives, rapid onset, and minimal residual effects have been developed. Dose-dependent amnesia is also produced by some of these agents. Advances in understanding receptor physiology have shed light on specific pharmacologic activities and aided the discovery of benzodiazepine antagonists with antidote properties. While these drugs have relatively low toxicity, dose-related oversedation remains a risk in susceptible patients, especially when combined with other sedatives.

Opioid supplementation to propofol anaesthesia for outpatient abortion: a comparison between alfentanil, fentanyl and placebo

One hundred and sixty-four patients scheduled for elective termination of pregnancy under general anaesthesia were randomly assigned to receive one of three different supplements to propofol and oxygen in nitrous oxide anaesthesia: 0.1 mg fentanyl, 0.5 mg alfentanil or placebo. Postoperative pain and nausea, as well as complications during anaesthesia were studied. There were no differences in complications or complaints by surgeons during anaesthesia, and no patient in any group reacted unsatisfactorily to surgery. The patients in the placebo group consumed significantly more propofol during the procedure (P less than 0.001). No differences were seen in time until hospital discharge between the three groups. Complaints about postoperative pain were significantly less frequent among patients receiving fentanyl (P less than 0.01). The number of patients requesting postoperative analgetics, however, did not differ. There was no difference in the frequency of nausea or vomiting, but postoperative pain was found significantly to increase complaints of nausea (P less than 0.01) and also time until hospital discharge (P less than 0.01). In conclusion, opioid supplementation lowered the amount of propofol needed for anaesthesia. Alfentanil 0.5 mg did not improve the postoperative course. Fentanyl 0.1 mg decreased the frequency of postoperative pain without increasing the time to hospital discharge.

A comparison of oral midazolam solution with temazepam as a day case premedicant

Seventy-five women undergoing elective day case gynaecological surgery were randomised into one of three groups to receive an oral formulation of midazolam IV solution 10 mg, temazepam 20 mg or placebo for premedication. The two treatment groups showed a significant reduction in anxiety score compared with placebo (P less than 0.002 and P less than 0.04 for placebo compared with temazepam and midazolam respectively). Similarly the treatment groups showed a significantly greater sedation score compared with placebo. Recovery as assessed by letter deletion and memory tests was no worse for the treatment groups than for placebo. Patient acceptance of the two treatment groups was significantly greater than that of placebo. There was no significant difference between treatment groups with respect to anxiolysis, sedation or recovery. As a day case premedicant, midazolam IV solution 10 mg orally was found to be as effective as temazepam 20 mg and superior to placebo, in terms of anxiolysis and sedation, but did not offer any clinical advantage over temazepam in this setting.

Premedication before elective breast surgery, a comparison between ketobemidone and midazolam

One hundred female patients scheduled for elective breast surgery (mean age 60 +/- 11 years were randomly assigned to receive one of two premedications: ketobemidone (Ketogan) 1-1.5 ml or midazolam 4-5 mg, intramuscularly. The effects on preoperative anxiety and postoperative emetic sequelae were studied. All patients were anaesthetised with thiopentone, fentanyl and atracurium, and ventilated with a mixture of nitrous oxide in oxygen with supplementary isoflurane. Sixty-nine percent of the midazolam- and 50% of the ketobemidone-premedicated patients experienced a reduction in anxiety. Midazolam was found to be more effective than ketobemidone in reducing anxiety among more tense patients--those with a VAS grading before premedication of 2 or more (P less than 0.05). Midazolam-premedicated patients were also assessed by observers as being more relaxed (P less than 0.05). No difference was seen in the frequency of emetic sequelae: 20 patients in the midazolam group and 14 patients in the ketobemidone group vomited once or more during the 24-h observation period. There was no difference between the two groups in time until an analgetic was required. In conclusion, midazolam seemed more effective in reducing preoperative anxiety than ketobemidone without any negative effects on postoperative emesis or time until an analgetic was required.

A comparison of morphine-perphenazine and midazolam on preoperative sedation and arterial oxygen saturation

The effectiveness of midazolam and a mixture of morphine-perphenazine premedication to produce sedation and their effects on preoperative oxygen saturation (SaO2) were examined. Eighty-five patients whose SaO2 measured with a pulse oximeter was greater than 90% and who were not receiving narcotic sedatives or oxygen were randomized to three groups. Each patient had his SaO2 recorded before premedication with placebo (saline), midazolam 0.08 mg.kg-1 or morphine 0.15 mg.kg-1 with perphenazine 2.5-5.0 mg im. From 30-90 min later, prior to anaesthesia SaO2 was repeated, and a sedation score was obtained by a blinded observer using a seven point scale. Median sedation scores were greater for midazolam (4) than for morphine-perphenazine (2) and placebo (1) (P less than 0.0001). As well, there was a decrease in the SaO2 in the morphine-perphenazine group (1.7 +/- 2.7%, P less than 0.001) but not in the midazolam and placebo groups (0.1 +/- 2.3%, -0.8 +/- 2.1%). In conclusion midazolam produced greater sedation than morphine-perphenazine and placebo without effect on SaO2 whereas morphine-perphenazine showed a decrease in SaO2 preoperatively.

Patients' experiences of postoperative respirator treatment--influence of anaesthetic and pain treatment regimens

The influences of premedication, anaesthetic agents, and postoperative sedation and pain treatment regimens on the experiences of postoperative respirator treatment of surgical patients (n = 107) have been assessed. Of the patients, 55% recalled the respirator treatment. Administration of anticholinergic drugs and halogenated anaesthetic agents was found to impair the memory process and reduce the number of recallers, and sedation in the ICU with benzodiazepines was found to decrease the number of discomforts experienced by the recalling patients. Most of the patients who received treatment postoperatively for pain, mainly by epidural administration of local anaesthetic agents and/or morphine, recalled the respirator treatment period (85%), as compared to only 50% of the patients receiving intravenous opioids. The number and type of complaints experienced by patients receiving epidural pain treatment did not, however, differ from those reported by intravenously treated patients, and no significant adverse psychological reactions seemed to occur. It is concluded that the use of mainly regional techniques, when appropriate, for pain treatment of surgical patients needing postoperative ventilatory support seems advantageous. The primary aim of relieving pain from the wound area is achieved, allowing such light intravenous sedation and pain treatment that the possibility of communication and giving comforting reassurance is maintained. Such nursing care may be more efficient in helping the patient to cope with the stressful respirator treatment situation then heavy intravenous sedation and pain treatment regimens.

Preoperative anxiety: detection and contributing factors

The purpose of this study was to determine whether there is a correlation between anxiety the night before surgery and that existing immediately preoperatively, whether anaesthetists can detect preoperative anxiety and to establish the presence of any factors that might assist in the determination of preoperative anxiety. Anxiety was measured objectively using the Spielberger State-Trait Anxiety Inventory (STAI), and the Multiple Affect Adjective Check List (MAACL). Anxiety was found to be higher in females and those not having had a previous anaesthetic, and to remain constant from the afternoon before surgery to the immediate preoperative period. Anaesthetists were found to be poor assessors of anxiety unless they specifically questioned their patients about this.

Double-blind comparison of midazolam and temazepam as oral premedicants for outpatient anaesthesia

Oral premedication with midazolam 7.5 mg was compared with temazepam 20 mg in a double-blind study of sixty patients undergoing day-stay urological surgery. One hour following ingestion similar degrees of anxiolysis and sedation were reported by patients for both compounds. However, midazolam was observed by anaesthetists to produce the greater anxiolytic effect and was given the better overall assessment. Midazolam produced significantly greater amnesia both at the time of induction and 30 minutes postoperatively. At the time of discharge four hours postoperatively no significant difference could be observed in psychomotor performance or subjective sedation although on the evening of surgery the temazepam group had a greater incidence of sleepiness and an earlier time to retiring. Although the differences were small, the residual post-discharge effects of temazepam lead us to conclude that midazolam 7.5 mg is the more suitable premedicant for outpatient use.