Comparison between propofol and midazolam as sedative agents for surgery under regional anaesthesia

Correlating the Depth of Sedation Between the Ramsay Sedation Scale and Bispectral Index Using Either Intravenous Midazolam or Intravenous Propofol in Elderly Patients Under Spinal Anaesthesia

BACKGROUND

Supplementation of spinal anaesthesia with sedatives or anxiolytics has emerged as a standard protocol to alleviate patients' anxiety and to produce amnesia during the surgical procedure. Thus, judicious use of sedation can make surgeries under spinal anaesthesia more comfortable and acceptable for the elderly patient, the surgeon, and the anaesthesiologist. However, over-sedation may jeopardise the safety of the patient. Appropriate sedation helps reduce physiological stress, which leads to a better result. Therefore, monitoring the depth of sedation becomes essential. The Ramsay sedation scale (RSS) and bispectral index (BIS) both are used widely to assess the depth of sedation.

OBJECTIVES

The primary objective of the study was to assess and correlate the depth of sedation between the BIS and RSS in elderly patients using midazolam and propofol under spinal anaesthesia. The secondary objectives were to observe any difference in the commencement of sedation between the two groups and to observe haemodynamic changes between the two groups.

METHODS

A total of 60 elderly patients undergoing urological procedures under spinal anaesthesia were randomly assigned to receive either midazolam (Group A, n=30) or propofol (Group B, n=30) for sedation. In Group A, patients were given an initial bolus of midazolam 0.03 mg/kg and a maintenance incremental bolus of 0.01 mg/kg up to a maximum of 2.5 mg in 10-minute intervals. Group B used propofol with an initial bolus dose of 0.5 mg/kg over two minutes and a maintenance bolus of 10-20 mg as required for the maintenance of sedation depth. Sedation was titrated to achieve a BIS score of 70-80 and an RSS score of 3-4. Heart rate, non-invasive systolic, diastolic, mean arterial blood pressure, oxygen saturation (SPO2), and the correlation coefficient between the BIS and RSS were measured at 0 (baseline), 5, 10, 20, 30, 40, 50, and 60 minutes of interval.

RESULTS

The correlation coefficient between the BIS and RSS scores in Group A at various time intervals indicate a strong correlation coefficient of -0.76 at five minutes, -0.64 at 20 minutes, -0.78 at 30 minutes, -0.56 at 40 minutes, and -0.39 at 50 minutes. In Group B, the correlation coefficient between the BIS and RSS scores at various time intervals indicate a strong correlation coefficient of -0.75 at five minutes, -0.76 at 20 minutes,-0.64 at 30 minutes, -0.89 at 40 minutes, and -0.46 at 50 minutes of interval. We also observed that the BIS drops to a lower level in patients receiving propofol (Group B) with a significant difference depicting early onset of sedation with propofol. In Group B, HR and MAP were significantly less than those of Group A. There was no significant difference in terms of mean age, sex, and body weight in the patients of both groups.

CONCLUSION

The BIS and RSS scores indicate a strong correlation with a magnitude of 70%-80%, but more in Group B (propofol) than Group A (midazolam). Therefore, the characteristics of each sedative drug can influence the level of sedation during spinal anaesthesia. Clinicians should use a combination of BIS values and other objective sedative methods to determine the degree of sedation, rather than relying exclusively on BIS values.

The interaction between Epstein-Barr virus and multiple sclerosis genetic risk loci: insights into disease pathogenesis and therapeutic opportunities

Multiple sclerosis (MS) is a chronic neurodegenerative autoimmune disease, characterised by the demyelination of neurons in the central nervous system. Whilst it is unclear what precisely leads to MS, it is believed that genetic predisposition combined with environmental factors plays a pivotal role. It is estimated that close to half the disease risk is determined by genetic factors. However, the risk of developing MS cannot be attributed to genetic factors alone, and environmental factors are likely to play a significant role by themselves or in concert with host genetics. Epstein-Barr virus (EBV) infection is the strongest known environmental risk factor for MS. There has been increasing evidence that leaves little doubt that EBV is necessary, but not sufficient, for developing MS. One plausible explanation is EBV may alter the host immune response in the presence of MS risk alleles and this contributes to the pathogenesis of MS. In this review, we discuss recent findings regarding how EBV infection may contribute to MS pathogenesis via interactions with genetic risk loci and discuss possible therapeutic interventions.

Dexmedetomidine and Midazolam Sedation Reduces Unexpected Patient Movement During Dental Surgery Compared With Propofol and Midazolam Sedation

PURPOSE

Owing to its unpredictability, unexpected patient movement is one of the most important problems during surgery while under monitored anesthesia care with sedation. The purpose of this study was to compare unexpected patient movement during dental surgery while under dexmedetomidine and propofol sedation.

MATERIALS AND METHODS

The authors designed and implemented a prospective randomized controlled trial. Patients undergoing dental surgery requiring intravenous sedation were randomly assigned to dexmedetomidine and midazolam (dexmedetomidine group) or propofol and midazolam (propofol group) sedation. In each group, midazolam 0.02 mg/kg was administered in conjunction with continuous administration of dexmedetomidine or propofol to maintain a bispectral index value of 70 to 80. Unexpected patient movement interfering with the procedure was defined as acceptable, defined as no body movement or only 1 controllable movement, or unacceptable, defined as at least 2 controllable movements or any uncontrollable movement. The primary outcome was unexpected patient movement, and the secondary outcome was defined as snoring and cough reflex. Other variables included demographic and procedural characteristics. Continuous or ordinal variables were analyzed using the Student t test or Mann-Whitney test. Dichotomous or categorical variables were analyzed using the χ² test or Fisher exact test. A P value less than.05 was considered statistically significant.

RESULTS

Eighty-eight patients were enrolled in the study (dexmedetomidine group, n = 44; propofol group, n = 44). There were no relevant differences between groups for demographics and baseline variables. Intraoperative unacceptable patient movement occurred more commonly in the propofol group (n = 13; 30%) than in the dexmedetomidine group (n = 4; 9%; P = .015). Intraoperative snoring occurred more commonly in the dexmedetomidine than in the propofol group (P = .045). Incidence and number of cough reflexes were comparable between groups.

CONCLUSION

Dexmedetomidine and midazolam sedation decreases unexpected patient movement during dental surgery compared with propofol and midazolam sedation.

Conscious Intravenous Sedation in Dentistry: A Review of Current Therapy

Several sedation options are used to minimize pain, anxiety, and discomfort during oral surgery procedures. Minimizing or eliminating pain and anxiety for dental care is the primary goal for conscious sedation. Intravenous conscious sedation is a drug-induced depression of consciousness during which patients respond purposefully to verbal commands. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate as well as cardiovascular function. Patients must retain their protective airway reflexes, and respond to and understand verbal communication. The drugs and techniques used must therefore carry a broad margin of safety.

Conscious sedation for middle ear surgeries: A comparison between fentanyl-propofol and fentanyl-midazolam infusion

INTRODUCTION AND AIM

Middle ear surgeries can be performed under local anesthesia and sedation and can be well tolerated by the patient with minimal discomfort. This study was undertaken to compare two techniques of conscious sedation, intravenous midazolam, and propofol infusion for tympanoplasty.

MATERIALS AND METHODS

Forty patients scheduled for right or left tympanoplasty. American Society of Anesthesiologists I or II in age group 18-75 years were included in the study. The patients were randomly allocated into one of the two groups to receive either propofol (group I) or midazolam (group II).

RESULTS

The mean duration of anesthesia was 116.00 ± 33.94 min in group I, while 97.50 ± 30.76 min in group II (P = 0.07). The modified Ramsay sedation scale was not statistically significant in both the groups. In group I, 70% of the patients and 95% of the patients in group II had amnesia during the surgery (P = 0.091). The mean visual analog scale (VAS) score for surgeons and patients was not statistically significant in both the groups. In group I there was a positive correlation between the total dose of fentanyl and VAS score for surgeons (P = 0.02). There was also a positive correlation between the total dose of propofol and VAS score for surgeons (P = 0.034) and patients (P = 0.039) in group I.

CONCLUSION

Though propofol had shown a faster recovery and less nausea vomiting, we need a larger sample size to conclude, which of the technique is better. Both the techniques are safe, simple and versatile and provide excellent sedation with rapid trouble free recovery.

Increase of paradoxical excitement response during propofol-induced sedation in hazardous and harmful alcohol drinkers

BACKGROUND

Paradoxical excitement response during sedation consists of loss of affective control and abnormal movements. Chronic alcohol abuse has been proposed as a predisposing factor despite lack of supporting evidence. Because alcohol and propofol have a common site of action, we postulated that paradoxical excitement responses during propofol-induced sedation occur more frequently in hazardous and harmful alcohol drinkers than in social or non-drinkers.

METHODS

One hundred and ninety patients undergoing orthopaedic knee joint surgery were enrolled in this prospective and observational study. Subjects were divided into Group HD (hazardous and harmful drinkers) or Group NHD (no hazardous drinkers) according to the alcohol use disorder identification test (AUDIT). In study 1, propofol infusion was adjusted to achieve the bispectral index at 70-80 using target-controlled infusion. In study 2, the target concentration of propofol was fixed at 0.8 (study 2/Low) or 1.4 μg ml(-1) (study 2/High). Paradoxical excitement responses were categorized by intensity into mild, moderate, or severe.

RESULTS

The overall incidence of paradoxical excitement response was higher in Group HD than in Group NHD in study 1 (71.4% vs 43.8%; P=0.022) and study 2/High (70.0% vs 34.5%; P=0.006) but not in study 2/Low. The incidence of moderate-to-severe response was significantly higher in Group HD of study 1 (28.6% vs 3.1%; P=0.0005) and study 2/High (23.3% vs 3.4%; P=0.029) with no difference in study 2/Low. Severe excitement response occurred only in Group HD of study 1 and study 2/High.

CONCLUSIONS

Paradoxical excitement occurred more frequently and severely in hazardous and harmful alcohol drinkers than in social drinkers during propofol-induced moderate-to-deep sedation, but not during light sedation.

[Sedation in surgical procedures using regional anesthesia in adult patients: results of a survey of Spanish anesthesiologists]

OBJECTIVE

To analyze the frequency and methods of sedation used in the context of regional anesthesia in adults by means of a national survey.

MATERIAL AND METHODS

We carried out a survey of participants at the courses of an anesthesiology training organization (Fundación Europea de Enseñanza en Anestesiología), held in Spain in 2006. The survey questionnaires asked about indications for sedation used during surgery under regional anesthesia as well as the form of administration, follow-up, and complications.

RESULTS

A total of 375 questionnaires were sent out and 185 responses were received (49.3%). Sedation is always used to accompany regional anesthesia by 69.2% of the respondents; 13.5% of them discuss the technique to be used with the patient and come to an agreement. The same type of sedation, regardless of the regional block performed, is used by 49.2% of respondents, and 64.3% use a scale to evaluate the level of sedation. The most favored sedation technique is continuous infusion, followed by target controlled infusion and boluses on demand. The most commonly used technique is sedation with bolus injections. Sixty percent use a single agent and 38.9% use combinations. The most commonly reported adverse effects are variability of patient response (53.5%) and respiratory complications (27%). In cases of ineffective regional blockade, 49.2% of those surveyed switch to general anesthesia.

CONCLUSIONS

Sedation is very often used to complement regional anesthesia in adult patients. Even though continuous infusion is considered to be the most appropriate form of administration, the most commonly used form is injection of boluses. Sedation with a single drug is used more frequently than drug combinations. Variability of individual response is the complication most commonly reported by the respondents.

Neuroleptanesthesia: current status

PURPOSE

To review the current status and possible future of neuroleptanalgesia/anesthesia, techniques that may be nearly extinct.

SOURCE

Articles from 1966 to present were obtained from the Current Science and Medline databases. Search terms include neurolepananalgesia/anesthesia, conscious sedation, droperidol, benzodiazepines, propofol, ketamine, and opioids. Information and abstracts obtained from meetings on this topic helped complete the collection of information.

PRINCIPAL FINDINGS

Droperidol/fentanyl may still be clinically indicated in the management of surgical seizure therapy for electrocorticography. However, the high incidence of post-operative sedation and restlessness discourage its use for other surgical or diagnostic procedures. Many surgical interventions, once thought ideally suited for neuroleptic agents, now meet better success with newer medications. The use of midazolam and/or propofol, in association with newer opioids, provides ideal anesthetic combinations.

CONCLUSION

The advantages of newer anesthetic agents have redefined the clinical indications for neuroleptanesthesia. In routine modern anesthesia, anxiolysis, sedation, and/or analgesia is better provided, with quicker recovery, by the new pharmacokinetic and pharmacodynamic characteristics of recent medications than by the neuroleptic component of neuroleptanesthesia.

Haemodynamic effects of induction of general anaesthesia with propofol during epidural anaesthesia

PURPOSE

To clarify whether propofol administration during thoracic or lumbar epidural anaesthesia intensifies the haemodynamic depression associated with epidural anaesthesia.

METHODS

Patients (n = 45) undergoing procedures of similar magnitude were randomly divided into three study groups: a control group (n = 15) receiving general anaesthesia alone and two study groups undergoing thoracic (n = 15) and lumbar epidural anaesthesia (n = 15) before induction of general anaesthesia. All patients received 2 mg.kg-1 propofol at a rate of 200 mg.min-1, followed by a continuous infusion of 4 mg.kg-1.hr-1. Mean arterial blood pressure (MAP) and heart rate (HR) were measured at baseline, three minutes after induction, and one minute after tracheal intubation in all three groups and at 20 min after epidural anaesthesia was established in the thoracic and lumbar groups.

RESULTS

Following epidural anaesthesia, MAP decreased from 94 +/- 14 (SD) at baseline to 75 +/- 11 mmHg (P < 0.0001) in the thoracic group and from 92 +/- 12 to 83 +/- 15 mmHg in the lumbar group. After propofol administration, MAP decreased further in the thoracic group to 63 +/- 9 mmHg (P = 0.0077) and to 67 +/- 10 mmHg (P = 0.0076) in the lumbar group. The MAP following propofol induction in the thoracic group (P < 0.0001) and in the lumbar group (P = 0.0001) was lower than MAP in the control group (81 +/- 9 mmHg). HR decreased only in response to thoracic epidural anaesthesia (P = 0.0066).

CONCLUSION

The hypotensive effects of propofol are additive to those of epidural anaesthesia, resulting in a profound decrease in mean arterial pressure.

Propofol and fentanyl compared with midazolam and fentanyl during third molar surgery

PURPOSE

The purpose of this study was to measure the safety and efficacy of propofol combined with fentanyl as sedative agents during third molar outpatient surgery.

PATIENTS AND METHODS

A double-blind, prospective, randomized clinical trial involving 57 patients undergoing removal of third molars under intravenous sedation between November 1994 and December 1995 was performed. Patients randomly received either propofol and fentanyl (P + F, th = 24) or midazolam and fentanyl (M + F, M = 33). Patient demographics, Corah anxiety scores, and physiologic parameters were determined preoperatively. All medications were titrated to the same clinical end point for sedation. Intraoperative physiologic parameters, cooperation, alertness, and pain scores were assessed. Postoperative recovery and degree of amnesia also were determined.

RESULTS

There were no significant differences in either patient demographics or surgical characteristics between groups. The P + F group was significantly less cooperative than the M + F group. Pain during injection of propofol was a significant adverse side effect. Both groups experienced a small percentage of apneic episodes, but mechanical ventilation was never required. There were no differences in recovery between groups as measured by the Treiger dot test and psychomotor recovery scores. The degree of anterograde amnesia was greater for the M + F group, although the difference was not statistically significant. Sedation was rated good to excellent by the patient, surgeon, and observer, and there were no statistically significant differences between groups.

CONCLUSION

Propofol appears to be a safe and efficacious drug for use during outpatient oral surgical procedures.

Conscious sedation for interventional neuroradiology: a comparison of midazolam and propofol infusion

PURPOSE

The aim of this study was to compare two conscious sedation techniques, midazolam (M) and propofol (P), for interventional neuroradiology by assessment of the incidence of complications and satisfaction scores.

METHODS

Forty patients were randomized to receive 0.75 micrograms.kg-1 fentanyl and a M or P bolus followed by an infusion (M 15 micrograms.kg-1 + 0.5 micrograms.kg-1.min-1; P 0.5 mg.kg-1 + 25 micrograms.kg-1 min-1). The incidences of complications and untoward events requiring intervention were documented. These included respiratory depression, excessive pain, inappropriate movements and the inability to examine the patient. The satisfaction of the anaesthetic technique from the perspective of both the neuroradiologist and the patient was scored.

RESULTS

The incidence and types of complications were no different between the two groups. Pain occurred in 12 patients (6M, 6P), inappropriate movements in 17 (7M, 10P) and respiratory changes in 10 patients (2M, 8P).

CONCLUSIONS

Both techniques were satisfactory and the incidence of complications was similar for both groups.

The use of propofol for sedation in the emergency department

OBJECTIVE

To evaluate the effectiveness of propofol and fentanyl when used by emergency physicians (EPs) for systemic sedation and analgesia in the ED.

METHODS

Over an eight-month period, a convenience sample of consenting patients at an urban teaching hospital ED who required sedation for painful procedures were enrolled in a descriptive study of therapeutic propofol sedation. After receiving 2 micrograms/kg of fentanyl i.v. the patients received a continuous infusion of propofol at 0.21 mg/kg/min i.v. to the desired level of sedation. A maintenance infusion of 3-6 mg/kg/hr was administered during the remainder of the procedure. Sedation time, total procedure time, and recovery time were recorded and the presence of side effects was noted. The patients and the physicians rated their satisfaction with the technique on a 100-mm visual analog scale. The patients were contacted at 24 hours for follow-up information.

RESULTS

Twenty patients (aged 19-62 years) received propofol infusion for procedures that included ten abscess incision and drainages, eight orthopedic reductions, one chest tube placement, and one wound exploration. The mean (+/- SD) total dose of propofol was 200 +/- 160 mg. The mean time to onset of sedation was 6.6 +/- 3.2 min, the mean procedure interval was 9.6 +/- 6.3 min, and the mean interval until recovery was 6.1 +/- 4.1 min. The median patient satisfaction score was 97 mm (range 40-100 mm); the median rating by physicians was 88 mm (range 4-100 mm). Side effects were noted in six patients: three had pain on injection, one had pain on injection and brief (< 1 min) hypotension (systolic blood pressure = 80 mm Hg), and two had apnea (< 30 sec). Seven patients had some recall of the procedure immediately afterwards, but only five had any recall at 24 hours. All 20 patients stated they would be willing to receive the same sedation again for a future procedure.

CONCLUSION

Propofol appears to be an effective agent to provide systemic sedation and analgesia when used in conjunction with fentanyl for procedures in the ED. Given its rapidity of onset and elimination, it may become a useful agent to EPs for i.v. sedation in the ED.

[Use of Diprivan in addition to locoregional anesthesia]

During regional anaesthesia, sedation can be used to obviate any discomfort which is unrelated to a technical insufficiency of the block or a particular anxiety of the patient. Sedation increases the acceptability of the technique by the patient. The main characteristics of propofol are its short onset time of action, and the rapid reversibility of its effects after the end of its administration. For induction of anaesthesia, propofol is given as a bolus injection, an average dose being 10 to 20 mg. Maintenance is best achieved with a continuous infusion, at a rate of 3 to 4 mg.kg-1.h-1. Titration of propofol allows the ideal stage of sedation to be reached (MacKenzie Grade 3), followed by a fast recovery. Close monitoring of the patient is mandatory and should include clinical supervision and pulse oximetry in all cases.

Intravenous sedation for ocular surgery under local anaesthesia

Anterior segment ophthalmic surgery is commonly performed under local anaesthesia. In order to improve patient comfort, a variety of sedation techniques has been employed in the past. The object of this study was, firstly, to determine whether continuous intravenous sedation during surgery offered any advantages in patients premedicated with temazepam and metoclopramide, and, secondly, to compare midazolam to propofol for this purpose. Forty nine patients were randomly allocated to receive no intravenous sedation (n = 15), continuous propofol infusion (n = 17), or continuous intravenous midazolam infusion (n = 17) after peribulbar anaesthesia. Each technique provided cardiovascular and respiratory stability and allowed early recovery with minimal postoperative sequelae. Unexpected ocular field movement occurred more commonly in the patients receiving intravenous sedation, although statistical significance was not shown (p = 0.06). Significantly more patients in the intravenous sedation groups reported amnesia (p = 0.03). Patient acceptability was good irrespective of the technique used. This study suggests that continuous sedation using propofol or midazolam is not beneficial and should be avoided in ophthalmic patients who have received a simple premedication.

Clinical pharmacology of propofol: an intravenous anesthetic agent

Propofol is a 2,6-diisopropylphenol with sedative-hypnotic properties. Because of its slight solubility in water, the drug is formulated as an emulsion for clinical use. It is highly lipophilic and distributes extensively in the body. The blood concentration-time profile of propofol after an iv bolus injection follows a three-compartment model with half-lives of 2-4 min, 30-45 min, and 3-63 h, respectively. Propofol is extensively metabolized by the liver prior to its elimination by the kidney. Following an iv dose of 2-2.5 mg/kg, loss of consciousness occurs in less than one minute and lasts for approximately five minutes. Hypnosis can be maintained by propofol blood concentrations of 1.5-6 micrograms/mL in the presence of N2O/O2 (60:40 ratio) or other anesthetic agents. During induction, propofol decreases the systolic and diastolic blood pressure by approximately 20-30 percent with minimal change in heart rate; apnea is also common. The cardiovascular and respiratory effects of propofol, however, should not cause major concern in otherwise healthy patients. By virtue of its pharmacokinetic profile, the drug lends itself to continuous infusion for maintenance of anesthesia. When used as the main anesthetic agent, it produces satisfactory anesthesia with rapid recovery and without major adverse effects in healthy individuals. In continuous infusion propofol can be used as an alternative to inhalation anesthetics.