Sedation in oral and maxillofacial day care surgery: A comparative study between intravenous dexmedetomidine and midazolam

Efficacy and cost analysis of intravenous conscious sedation for long oral surgery procedures

The aim of this study was to determine what is considered a long oral surgery and conduct a cost-effective analysis of sedative agents used for intravenous sedation (IVS) and sedation protocols for such procedures. Pubmed and Google Scholar databases were used to identify human studies employing IVS for extractions and implant-related surgeries, between 2003 and July/2023. Sedation protocols and procedure lengths were documented. Sedative satisfaction, operator satisfaction, and sedation assessment were also recorded. Cost estimation was based on The British National Formulary (BNF). To assess bias, the Cochrane Risk of Bias tools were employed. This review identified 29 randomised control trials (RCT), six cohorts, 14 case-series, and one case-control study. The study defined long procedures with an average duration of 31.33 minutes for extractions and 79.37 minutes for implant-related surgeries. Sedative agents identified were midazolam, dexmedetomidine, propofol, and remimazolam. Cost analysis revealed midazolam as the most cost-effective option (<10 pence per procedure per patient) and propofol the most expensive option (approximately £46.39). Bias analysis indicated varying degrees of bias in the included studies. Due to diverse outcome reporting, a comparative network approach was employed and revealed benefits of using dexmedetomidine, propofol, and remimazolam over midazolam. Midazolam, dexmedetomidine, propofol, and remimazolam demonstrated safety and efficacy as sedative agents for conscious IVS in extended procedures like extractions or implant-related surgeries. While midazolam is the most cost-effective option, dexmedetomidine, propofol, and remimazolam offer subjective and clinical benefits. The relatively higher cost of propofol may impede its widespread use. Dexmedetomidine and remimazolam stand out as closely priced options, necessitating further clinical investigations for comparative efficacy assessment.

Opioid requirement and pain intensity after mandibular surgeries with dexmedetomidine administration in two ways: intraoperative infusion versus bolus injection

PURPOSE

The purpose of this study is to compare the opioid requirement and pain intensity after surgeries of mandibular fractures with administration of dexmedetomidine by two approaches of infusion and single bolus.

METHODS

In this double-blind clinical trial, the participants were randomized and matched in terms of age and gender in two groups (infusion and bolus). In both groups, the amount of narcotic used, hemodynamic indices, oxygen saturation, and pain intensity were collected based on the ten-point Visual Analogue Scale (VAS) at 7 time points for 24 h. SPSS version 24 software was used for data analysis. A significance level of less than 5% was considered.

RESULTS

A total of 40 patients were included in the study. There was no significant difference between the two groups in terms of gender, age, ASA class, and duration of surgery (P>0.05). There was no significant difference between the two groups in terms of nausea and vomiting and subsequently receiving anti-nausea medication (P>0.05). The need for opioid consumption after surgery was not different in two groups (P>0.05). Infusion of dexmedetomidine reduced postoperative pain more rapidly than its single bolus dose (P<0.05). However, over time, there was no significant difference between the two groups in terms of changes in oxygen saturation variables (P>0.05). Homodynamic indices including heart rate, systolic blood pressure, and diastolic blood pressure in the bolus group were significantly lower than the infusion group (P<0.05).

CONCLUSION

Administration of dexmedetomidine in the form of infusion can reduce postoperative pain better than bolus injection, with less probability of hypotension and bradycardia.

Effects of propofol, ketamine-propofol mixture in pediatric dental patients undergoing intravenous sedation: a clinical study

This study aimed to evaluate the clinical effects, complications (peri- and postoperative), depth of sedation, recovery times, and changes in anxiety levels in paediatric dental patients receiving intravenous sedation with propofol and ketamine-propofol mixtures. This prospective clinical study included 69 healthy children (ASA 1) aged 3-7 years. The patients were assigned randomly to propofol group (n = 23), which received propofol; 1:3 ketofol group (n = 23), which received 1:3 ketofol; or 1:4 ketofol group (n = 23), which received 1:4 ketofol. The bispectral index (BIS) and Ramsay Sedation Scale (RSS) score were recorded at intervals of 5 min to measure the depth of sedation, and vital signs were evaluated. Peri- and postoperative complications and recovery times were recorded. Anxiety levels were also evaluated using the Facial Image Scale (FIS) and changes in saliva cortisol levels (SCLs) before and after the intravenous sedation procedure. The Kruskal‒Wallis test and Wilcoxon signed-rank test were used to determine pre- and posttreatment parameters. Dunn's test for post hoc analysis was used to determine the differences among groups. Children's pre- and posttreatment anxiety levels did not differ significantly according to FIS scores, and increases in SCLs were detected in 1:3 ketofol and 1:4 ketofol groups after dental treatment was completed. Compared with those in the other groups, the BIS values of the patients in 1:4 ketofol indicated a slightly lower depth of sedation. The recovery time of the patients in 1:3 ketofol was longer than that of patients in propofol and 1:4 ketofol. The incidence of postoperative complications (agitation, hypersalivation, nausea/vomiting, and diplopia) did not differ among the groups. Ketamine-propofol combinations provided effective sedation similar to that of propofol infusion without any serious complications during dental treatment performed under intravenous sedation. The ketofol infusion increased the anxiety level of paediatric dental patients to a greater extent than the propofol infusion.

Long-Term Satisfaction of Oral Sedation versus Standard-of-Care Intravenous Sedation for Ocular Surgery

Purpose

Long-term patient satisfaction may influence patients' perspectives of the quality of care and their relationship with their providers. This is a follow up to a comparative effectiveness study investigating oral to intravenous sedation (OIV study). The OIV study found that oral sedation was noninferior in patient satisfaction to standard intravenous (IV) sedation for anterior segment and vitreoretinal surgeries. This study aims to determine if patient satisfaction with oral sedation remained noninferior long term.

Patients and Methods

Patients were re-interviewed using the same satisfaction survey given during the OIV study. Statistical analysis involved t-tests for noninferiority of the long-term mean satisfaction score of oral and IV sedation. We also compared the original mean satisfaction score and the follow-up mean satisfaction score for each type of sedation and for both groups combined.

Results

Participants were interviewed at a median of 1225.5 days (range 754-1675 days) from their surgery. The original mean satisfaction score was 5.26 ± 0.79 for the oral treatment group (n = 52) and 5.27 ± 0.64 for the intravenous treatment group (n = 46), demonstrating noninferiority with a difference in mean satisfaction score of 0.015 (p < 0.0001). The follow-up mean satisfaction score was 5.23 ± 0.90 for oral sedation and 5.60 ± 0.61 for IV sedation, with a difference in the mean satisfaction score of 0.371 (p = 0.2071). Satisfaction scores did not differ between the original mean satisfaction score and the follow-up mean satisfaction score for the oral treatment group alone (p = 0.8367), but scores in the intravenous treatment group increased longitudinally (p = 0.0004).

Conclusion

In this study, long-term patient satisfaction with oral sedation was not noninferior to satisfaction with IV sedation, unlike our findings with short-term patient satisfaction in our original study. Patient satisfaction also remained unchanged over time for the oral treatment group, but patients in the intravenous treatment group reported higher long-term satisfaction with their anesthesia experience compared to the immediate post-operative period.

The effect of mindfulness meditation on dental anxiety during implant surgery: a randomized controlled clinical trial

Dental implant surgery is almost always associated with patient anxiety. Anxiety during dental surgical procedures triggers an increase in sympathetic activity. Mindfulness meditation (MM) is often associated with high levels of relaxation in the form of increased parasympathetic tone and decreased sympathetic activity. However, the effect of MM on dental anxiety is not clear. The current study aimed to show the effects of a MM as a sedative technique during dental implant surgery by examining the State-Trait Anxiety Inventory (STAI-S), bispectral index (BIS), cortisol levels (CL), systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and saturation (SpO2) parameters. HR, SBP, DBP, SpO2, BIS score and CLs were compared at the baseline, immediately before-, during-, and immediately after surgery between the test and control groups. We found that the MM resulted in significant decrease in BIS together with positive effects on hemodynamic parameters (decrease of HR, SBP, DBP and increase of SpO2), psychological findings (improvement on STAI-S scores) and biochemical outcomes (decreased CL). In conclusion, the results demonstrate that MM appeared to be a reliable strategy for managing stress during dental implant operation with benefits in psychological, physiological and biochemical outcomes.

Systematic review and meta-analysis comparing the efficacy of dexmedetomidine to midazolam as premedication and a sedative agent in pediatric patients undergoing dental procedures

INTRODUCTION

Pediatric dental surgeries are associated with the emotions of fear, anxiety, and other behavioral disturbances of children that need to be managed. Sedation using drugs like dexmedetomidine (DEX) and midazolam (MID) is a common pharmacological behavior managing technique. We conducted this meta-analysis to evaluate the efficacy of both these drugs in current literature.

METHODOLOGY

A thorough literature search was conducted on PubMed, MEDLINE, Google Scholar, and Cochrane's database for randomized studies that compared sedative efficacy of dexmedetomidine with midazolam in children of 0-15 years of age undergoing dental surgeries. Sedation in children during dental procedure, when used as a premedication, at the time of separation from parents and at the time of mask induction, onset time, duration of anesthesia, and surgery were evaluated. The mean differences (MDs), odds ratio (OR), and their 95% confidence intervals (CIs) were calculated both for continuous and dichotomous outcome data using random-effects model.

RESULTS

Seven studies met out inclusion criteria and were analyzed. Results of premedication with DEX was associated with more anxiolysis (OR=0.29, 95% CI: 0.17-0.52, p=0.0001; I2=0%) and at the time of separation from parents (OR=0.36, 95% CI: 0.19-0.69, p=0.002; I2=52%) in comparison to MID. No significant differences in results were seen at mask induction (OR=0.63, 95% CI: 0.34-1.18, p=0.15; I2=47%) and for sedation in children during dental procedures (OR=0.52, 95% CI: 0.07-3.70, p=0.51; I2=72%). Also, there were no significant differences in onset time, duration of anesthesia, and surgery between the two agents.

CONCLUSION

DEX proved to be a better premedicant than MID for pediatric patients. No significant difference in efficacy of both sedative agents was observed in children undergoing dental treatment. More clinical trials need to be conducted to see its efficacy in dental surgeries in children of standardized ages and with standard doses.

Comparison of the Efficacy of Midazolam and Dexmedetomidine As Sedative Agents in Third Molar Surgery

Introduction Minor dental and oral surgical procedures have been made comfortable with the rise in the use of daycare sedatives. Of these sedatives, midazolam is deemed a common sedative used for minor oral surgical procedures. Newer and safer sedatives such as dexmedetomidine have certain properties that may prove more efficient in oral surgical procedures. Third molar surgery is one of the most common minor oral surgical procedures performed in dentistry. Thus, this study aims to compare the efficacy of midazolam and dexmedetomidine as sedative agents in third molar surgery. Materials and methods Sixty young adult patients free from other comorbidities were included in the study with ages ranging between 18 and 50 years. The samples were matched for the difficulty of impacted teeth and randomly distributed among the groups. Groups were administered the respective sedative drugs midazolam and dexmedetomidine and their effects were observed through the Observer's Assessment of Alertness/Sedation scale. The intraoperative vitals and sedation effects were checked every 15 minutes. Statistical analysis was done using IBM SPSS Statistics for Windows, Version 22 (Released 2013; IBM Corp., Armonk, New York, United States). Independent samples t-test and analysis of variance were the statistical tests employed to analyze the obtained data with p<0.05 considered as statistically significant. Results The depth of sedation has been both subjectively and objectively assessed and had no significant difference among the groups. The intra-operative heart rate assessment proved a more efficient reduction of pulse rate in the dexmedetomidine group as compared with the midazolam group. However, it was not statistically significant (p=0.121). The mean diastolic blood pressure showed a statistically significant difference between the groups with dexmedetomidine having lower blood diastolic pressure compared to midazolam (p=0.004). Quick arousal was witnessed in the dexmedetomidine group. Conclusion It can be concluded from the study that both dexmedetomidine and midazolam were equally effective as sedative agents for third molar surgery. However, the nature of cardio-protection, anti-sialagogue, and analgesic properties of dexmedetomidine can prove helpful, especially in minor oral surgical procedures like third molar surgery and it is recommended.

Effects of dexmedetomidine in non-operating room anesthesia in adults: a systematic review with meta-analysis

BACKGROUND

Dexmedetomidine (DEX) is an α2-adrenergic receptor agonist used for its sedative, analgesic, and anxiolytic effects. Non-Operating Room Anesthesia (NORA) is a modality of anesthesia that can be done under general anesthesia or procedural sedation or/and analgesia. In this particular setting, a level-2 sedation, such as the one provided by DEX, is beneficial. We aimed to study the effects and safety of DEX in the different NORA settings in the adult population.

METHODS

A systematic review with meta-analysis of randomized controlled trials was conducted. Interventions using DEX only or DEX associated with other sedative agents, in adults (18 years old or more), were included. Procedures outside the NORA setting and/or without a control group without DEX were excluded. MEDLINE, ClinicalTrials.gov, Scopus, LILACS, and SciELO were searched. The primary outcome was time until full recovery. Secondary outcomes included hemodynamic and respiratory complications and other adverse events, among others.

RESULTS

A total of 97 studies were included with a total of 6,706 participants. The meta-analysis demonstrated that DEX had a higher time until full recovery (95% CI = [0.34, 3.13] minutes, a higher incidence of hypotension (OR = 1.95 [1.25, 3.05], p = 0.003, I2 = 39%) and bradycardia (OR = 3.60 [2.29, 5.67], p < 0.00001, I2 = 0%), and a lower incidence of desaturation (OR = 0.40 [0.25, 0.66], p = 0.0003, I² = 60%).

CONCLUSION

DEX in NORA procedures in adults was associated with a lower incidence of amnesia and respiratory effects but had a long time to recovery and more hemodynamic complications.

Intranasal Dexmedetomidine in Elderly Patients (Aged > 65 Years) During Maxillofacial Surgery: Sedative Properties and Safety Analysis

PURPOSE

Light sedation rather than intravenous sedation is preferred when patients have a low heart rate and blood pressure during maxillofacial surgery. Intranasal administration of dexmedetomidine is reported to be efficacious and safe in adults. However, dexmedetomidine could be unsuitable for routine clinical use in elderly patients because many of these patients take β-blockers, which increase the cardiovascular effects of dexmedetomidine. The objectives of the study were to evaluate the sedative properties and safety of intranasal dexmedetomidine, regardless of concurrent β-blocker treatment, in elderly patients who underwent maxillofacial surgery.

METHODS

This study was a retrospective analysis of 535 patients aged > 65 years (American Society of Anesthesiologists physical status I or II) who were undergoing maxillofacial surgery. Very anxious patients and those with hypertension received intranasal 1 µg/kg dexmedetomidine through an intranasal mucosal atomization device before anesthesia (local ropivacaine).

RESULTS

Intranasal administration of dexmedetomidine decreased the requirement for midazolam before surgery (18 of 252 vs 63 of 283, P < .0001), but increased the requirement for norepinephrine (102 of 252 vs 8 of 283, P < .0001) during or after the surgery. A combination of a β-blocker and intranasal administration of dexmedetomidine reduced the hemodynamic parameters for an extended period. Intranasal administration of dexmedetomidine resulted in bradycardia and hypotension, regardless of concurrent β-blocker treatment.

CONCLUSIONS

Intranasal 1 µg/kg dexmedetomidine was associated with a high sedation score during the operation, but also with bradycardia and hypotension.

Injection of Lidocaine Alone versus Lidocaine plus Dexmedetomidine in Impacted Third Molar Extraction Surgery, a Double-Blind Randomized Control Trial for Postoperative Pain Evaluation

Objectives

Administration of medications such as dexmedetomidine as a topical anesthetic has been suggested in the pain control in dentistry. This double-blind randomized control trial study evaluated postoperative pain and associated factors following impacted third molar extraction surgery. Lidocaine alone was taken as the control and lidocaine plus dexmedetomidine as the intervention.

Materials and Methods

Forty patients undergoing mandibular third molar extraction entered the study and were randomly allocated to the control and interventional groups. 0.15 ml of dexmedetomidine was added to each lidocaine cartridge and the drug concentration was adjusted to 15 μg for the intervention group while only lidocaine was used in the control group. A visual analog scale was used to measure and record pain levels at the end of the surgery and 6, 12, and 24 hours after the surgery and number of painkillers taken by the patients after the surgery was also recorded.

Results

Pain scores of the intervention group decreased significantly during the surgery and also 6, 12, and 24 hours after the surgery compared to the control group. The pain score was correlated significantly with our intervention during the surgery and also 6 and 12 hours after that (all P value < 0.05). There was a nonsignificant reduction in the number of painkillers taken by the patients at 6, 12, and 24 hours after surgery (all P value > 0.05).

Conclusion

In patients undergoing molar surgery, administration of a combination of dexmedetomidine and lidocaine is beneficial for the pain control. Clinical Relevance. Compared to the injection of lidocaine alone, combination of dexmedetomidine and lidocaine can be used for a better pain control in molar surgeries.

Evaluation of endovenous sedation using BIS monitoring in dentistry. A systematic review

Background

The aim of the present review was evaluate the utility and validity of the Bispectral Index (BIS) in dental treatment carried out under endovenous sedation, and compare its efficacy with clinical sedation scales.

Material and Methods

Electronic and manual literature searches were conducted by two independent reviewers for articles published up to April 2017 in several databases, including Medline and Cochrane Library.

Results

Sixteen articles met the inclusion criteria. A correlation was identified between BIS and clinical sedation scales. A BIS range between 75 and 84 showed a high probability of corresponding to an Observer’s Assessment of Alertness and Sedation Scale (OAA/S) value of 3; a scored 3 on the Ramsay scale corresponds around 85 on the BIS; while BIS values between 57 and 64 corresponded to a University of Michigan Sedation Scale value of 3. BIS monitoring provides continuous measurement of the patient’s hypnotic state or state of consciousness, awareness, and recall. It proved impossible to perform an analysis of statistical data drawn from the studies reviewed due to the disparity of inclusion criteria among the works.

Conclusions

BIS for sedation monitoring might make possible to evaluate sedation levels objectively in real time, reducing the dose of the sedative required, increasing safety, and minimizing secondary effects.

Key words:Bispectral analysis, BIS monitoring, intravenous sedation, dental treatment, anesthetics.

Optimal level of bispectral index for conscious sedation in awake fiberoptic nasotracheal intubation

Background

Bispectral index (BIS) has been in practice as an objective tool to measure the depth of conscious sedation. The data on adequate levels for awake fiberoptic nasotracheal intubation (AFNI) is however scarce. We aimed to obtain an optimal level of BIS required for achieving the adequate conscious sedation in AFNI procedure.

Methods

In a prospective, observational, outcome assessor blinded cohort trial, 94 consecutive patients with anticipated difficult intubation and undergoing AFNI for any elective surgery were enrolled. The topical anesthesia and sedation were induced with lidocaine and dexmedetomidine, while keeping the patient awake. The sedation levels were targeted to BIS ≤90 and Ramsay sedation score (RSS)≥2 to attempt intubation. Propofol bolus were administered if patients get agitated. The primary outcome was "Stable BIS", the lowest BIS at which intubation could be feasibly performed. A receiver operator characteristic curve, Youden index, and correlation analysis were used.

Results

The optimal criterion for BIS was obtained as ≤86 (AUC: 0.80, sensitivity 88.30%, specificity 61.45%, Youden index 49.74). The stable BIS ranged from 80 to 88, while RSS varied from 1 to 3. The BIS and RSS correlated significantly (r: 0.83). The stable BIS was independent of any baseline characteristics. Six patients had transient untoward events, none requiring any intervention.

Conclusion

BIS serves as an effective objective tool for titrating the depth of conscious sedation. We advocate a BIS range of 80-86 for feasibly performing the AFNI procedure.

Comparison between Dexmedetomidine and Midazolam for Sedation in Patients with Intubation after Oral and Maxillofacial Surgery

The aim of the investigation is to clarify the beneficial sedative effects for patients with postoperative intubation in the intensive care unit (ICU) after oral and maxillofacial surgery. Forty patients with postoperative intubation were divided into two groups in method of random number table: midazolam group and dexmedetomidine group. The Ramsay score, the behavioral pain scale (BPS) score, SpO₂, HR, MAP, and RR were recorded before sedation (T0), 30 minutes (T1), 1 hour (T2), 2 hours (T3), 6 hours (T4), and 12 hours (T5) after dexmedetomidine or midazolam initiation in intensive care unit, and 10 minutes after extubation (T6). The rate of incidences of side effects was calculated. Sedation with midazolam was as good as standard sedation with dexmedetomidine in maintaining target sedation level. The BPS score in the midazolam group was higher than that in the dexmedetomidine group. The time of tracheal catheter extraction in the dexmedetomidine group was shorter than that in the midazolam group (p ≤ 0.001). The incidence of bradycardia in the dexmedetomidine group was higher than that in the midazolam group (p = 0.028). There was no statistically significant difference in the incidence of hypotension between the two groups (p = 0.732). The incidence of respiratory depression of group midazolam was higher than that of group dexmedetomidine (p = 0.018). The incidence of delirium in the dexmedetomidine group was significantly lower than that in the midazolam group, and the difference was statistically significant (p = 0.003). Dexmedetomidine and midazolam can meet the needs for sedation in ICU patients. And dexmedetomidine can improve patients' ability to communicate pain compared with midazolam.

Recovery time after oral and maxillofacial ambulatory surgery with dexmedetomidine: an observational study

OBJECTIVES

To evaluate the relationship between pharmacokinetic descriptors of dexmedetomidine (predicted area under the curve during the procedure, predicted plasma level at the end of the procedure, and duration of procedure) and sedation depth (proportion of time with bispectral index < 85 during the procedure) with recovery time after ambulatory procedures.

MATERIALS AND METHODS

Clinical observational study of patients undergoing oral and maxillofacial ambulatory surgery with dexmedetomidine as sole sedative agent. Patients received a loading dose of dexmedetomidine (0.25-1 μg kg^-1) followed by a maintenance infusion (0.2-1.4 μg kg^-1 h^-1) to keep a bispectral index < 85 until 5 min before the end of the procedure, and were transferred to a post-anesthesia care unit until criteria for discharge were met.

RESULTS

Data from 75 patients was analyzed. Sedation depth was directly associated with recovery time (Pearson correlation coefficient [r] = 0.26; p = 0.024). Around 7% of the variation in recovery time was explained by the proportion of time with bispectral index < 85. No association with procedure duration (r = 0.01; p = 0.9), predicted area under the curve (r = 0.1; p = 0.4), or predicted plasma level of dexmedetomidine at the end of the procedure (r = 0.12; p = 0.3) with recovery time was observed.

CONCLUSIONS

Sedation depth with dexmedetomidine could play a role in increasing recovery time after oral and maxillofacial ambulatory surgery. In our study, the pharmacokinetic descriptors of dexmedetomidine did not seem to influence recovery time.

CLINICAL RELEVANCE

Sedation depth with dexmedetomidine could play a role in increasing recovery time after ambulatory procedures.

Assessment of Alteration in Capnometry Monitoring during Intravenous Sedation with Midazolam for Oral Surgical Procedures

INTRODUCTION

Capnography is routinely used for monitoring of patients subjected to sedation for different surgical procedures. There is still paucity of data highlighting the capnographic assessment of patients on midazolam sedation undergoing oral surgical procedures. Hence, we planned the present study to assess the alterations occurring in the end-tidal carbon dioxide (ETCO₂) values monitored during intravenous (IV) sedation with midazolam during various oral surgical procedures.

MATERIALS AND METHODS

The present study included assessment of alteration in ETCO₂ values occurring during oral surgical procedure. After meeting the inclusion and exclusion criteria, a total of 40 participants were included in the present study. Pulse oximeter with capnograph (EmcoMeditek Pvt., Ltd., India) device was used for assessment of respiratory rate (RR) and ETCO₂ values. The mean of 12 readings over a period of 1 minute before the starting of first infusion was referred to as baseline time. By evaluating the first four readings at an interval of 15 seconds during the 1st minute of infusion, we obtained the 1 minute average reading. All the data were compiled and recorded and assessed by the Statistical Package for the Social Sciences (SPSS) software.

RESULTS

A total of 40 participants were included, out of which, 20 were males and 20 were females. At the baseline time, mean value of ETCO₂ was 31 mm Hg, while mean value of oxygen saturation (SpO₂) was 36%. Out of total 40 participants, 15 showed the presence of respiratory depression. Out of these 15 participants, ETCO₂ changes from baseline were observed in 13 participants.

CONCLUSION

No oxygen should be delivered, unless until required, to the healthy participants undergoing dental sedation procedures, for marinating the sensitivity of pulse oximetry during assessment of respiratory depression.

CLINICAL SIGNIFICANCE

In patients undergoing sedation procedures, various monitoring techniques should be employed as respiratory depression is a commonly encountered risk factor.