Comparison between dexmedetomidine and remifentanil for controlled hypotension during tympanoplasty:

Haemodynamic effects of remifentanil during induction of general anaesthesia with propofol. A randomised trial

BACKGROUND

Remifentanil may have a dose-dependent haemodynamic effect during the induction of general anaesthesia combined with propofol. Our objective was to investigate whether systolic arterial blood pressure (SAP) was reduced to a greater extent when the remifentanil dose was increased.

METHODS

This randomised, double-blind, dose-controlled study was conducted at the Day Surgery Unit of Haugesund Hospital, Norway. Ninety-nine healthy women scheduled for gynaecological surgery were randomly allocated in a 1:1:1 ratio to receive remifentanil induction with a low, medium or high dose corresponding to maximum effect-site concentrations (Ce) of 2, 4 and 8 ng/mL. The induction dose of propofol was 1.8 mg/kg, with a Ce of 2.9 μg/mL. Anaesthesia was induced using target-controlled infusion. After 150 s of sedation, a bolus of remifentanil and propofol was administered. Baseline was defined as 55-5 s before the bolus dose, and the total observation time was 450 s. We used beat-to-beat haemodynamic monitoring with LiDCOplus. The primary outcome variable was the maximum decrease in SAP within 5 min after bolus administration of remifentanil and propofol. Absolute and relative changes from baseline to minimal values and the area under the curve (AUC) were used as effect measures. Comparisons of groups were performed using analysis of variance (ANOVA).

RESULTS

Median remifentanil doses were 0.75, 1.5 and 3.0 μg/kg in the low-, medium- and high-dose groups, respectively. The absolute changes (mean ± standard deviation) in SAP in the low-, medium- and high-dose groups of remifentanil were -39 ± 9.6 versus -43 ± 9.1, and -41 ± 10 mmHg, respectively. No difference (95% confidence interval) in the absolute change in SAP was observed between the groups (ANOVA, p = .29); medium versus low dose 3.7 (-2.0, 9.4) mmHg, and high versus medium dose -2.2 (-8.0; 3.5) mmHg. The relative changes from baseline to minimum SAP values were -30% versus -32% versus -32% (p = .52). The between-group differences in the AUC were not statistically significant. Relative changes in heart rate (-20% vs. -21% vs. -21%), stroke volume (-19% vs. -16% vs. -16%), cardiac output (-32% vs. -32% vs. -32%), systemic vascular resistance (-24% vs. -27% vs. -28%), and AUC were not statistically significant.

CONCLUSION

This trial demonstrated major haemodynamic changes during the induction of anaesthesia with remifentanil and propofol. However, we did not observe any statistically significant differences between low, medium or high doses of remifentanil when using continuous invasive high-accuracy beat-to-beat monitoring.

Use of dexmedetomidine for controlled hypotension in middle ear surgery: A systematic review and meta-analysis

BACKGROUND

Microsurgical operations such as middle ear surgery rely heavily on visibility of the surgical field. Anesthetic techniques such as controlled hypotension have been developed to improve surgical field visibility by attempting to decrease bleeding. Many agents have been utilized to achieve controlled hypotension intraoperatively. Dexmedetomidine is a relatively newer agent which works on alpha-2 receptors to decrease sympathetic tone. This paper sought to determine the efficacy of dexmedetomidine for optimizing surgical field visibility in MES.

METHODS

A comprehensive search strategy was used in PubMed, SCOPUS, CINAHL, and CENTRAL through August 9, 2022 for this systematic review and meta-analysis.

INCLUSION CRITERIA

adult patients undergoing middle ear surgery with dexmedetomidine used for controlled hypotension to improve surgical field visibility. Risk of bias was assessed via Cochrane RoB 2. Meta-analysis of mean difference for surgical field scores and risk ratios for positive surgical field scores were used to compare dexmedetomidine with placebo or other agents.

RESULTS

Fourteen studies were included in this review. Statistically significant mean difference was found to favor dexmedetomidine over placebo for Fromme-Boezaart surgical field scores. Statistically significant results were also demonstrated favoring dexmedetomidine over other agents in risk ratio for receiving positive surgical field scores, as well as surgeon and patient satisfaction scores.

CONCLUSIONS

Controlled hypotension is an invaluable tool for surgical field visibility. Improved surgical field visibility was observed with dexmedetomidine compared with placebo and various other agents. Risk of sub-optimal bleeding scores was significantly lower with dexmedetomidine. Dexmedetomidine is effective at improving surgical field visibility in middle ear surgery.

Dexmedetomidine versus remifentanil for controlled hypotension under general anesthesia: A systematic review and meta-analysis

This meta-analysis aimed to analyze and compare the efficacy and safety of remifentanil and dexmedetomidine applied respectively for controlled hypotension under general anesthesia. We searched the Cochrane Library, PubMed, EMBASE, Web of Science, CNKI, SinoMed, Wanfang, and VIP databases, as well as dissertations and conference papers, to obtain randomized controlled trials comparing remifentanil and dexmedetomidine applied respectively for controlled hypotension before August 23, 2021. The primary outcomes included hemodynamic profiles, surgical field score, and blood loss. Extubation time, sedation and pain score at the PACU, and perioperative adverse events were the secondary outcomes. Nine randomized controlled trials with 543 patients (272 in the dexmedetomidine group and 271 in the remifentanil group) were eventually included. This meta-analysis indicated no significant difference between dexmedetomidine and remifentanil in terms of surgical field score, blood loss, minimum values of mean arterial pressure (MD 0.24 with 95% CI [-1.65, 2.13], P = 0.80, I2 = 66%) and heart rate (MD 0.42 [-1.33, 2.17], P = 0.64, I2 = 40%), sedation scores at the PACU (MD -0.09 [-0.69, 0.50], P = 0.76, I2 = 92%), and incidence of bradycardia (OR 2.24 [0.70, 7.15], P = 0.17, I2 = 0%). Compared with remifentanil, dexmedetomidine as the controlled hypotensive agent showed a lower visual analogue score at the PACU (MD -1.01 [-1.25, -0.77], P<0.00001, I2 = 0%) and incidence of shivering (OR 0.22 [0.08, 0.60], P = 0.003, I2 = 0%), nausea, and vomiting (OR 0.34 [0.13, 0.89], P = 0.03, I2 = 0%). However, extubation time was shorter in the remifentanil group (MD 3.34 [0.75, 5.93], P = 0.01, I2 = 90%). In conclusion, dexmedetomidine and remifentanil are both effective in providing satisfactory controlled hypotension and surgical conditions. Dexmedetomidine is better in easing postoperative pain at the PACU and reducing the occurrence of shivering, nausea, and vomiting. Meanwhile, remifentanil is a fast-track anesthesia with a shorter extubation time. Given the limitations of this meta-analysis, further studies are needed for a more definitive comparison of the efficacy and safety of dexmedetomidine and remifentanil.

Controlled Hypotension for Functional Endoscopic Sinus Surgery With Two Different Doses of Fentanyl

Background and Objectives Functional endoscopic sinus surgery (FESS) is a type of minimally invasive surgery done for acute and chronic sinus diseases or paranasal illnesses. The idea of FESS is to preserve the normal anatomy, which is non-obstructing and mucous membrane while removing tissue obstructing OMC (osteo metal complex) and facilitating drainage. The critical structures, including the brain, orbit, and carotid veins, the lack of adequate operating room, and bleeding that obscures endoscopic vision throughout the procedure may increase the likelihood of unfavorable surgical results. This study seeks to examine the hemodynamic effects of intubation and extubation as well as the impact of fentanyl infusion on lowering blood pressure during FESS procedures. Materials and Methods Sixty-eight patients from the American Society of Anesthesiologists classes 1 and 2 who were planned for functional endoscopic sinus operations were randomly split into two groups for this randomized prospective trial. Group 1 patient belonging to the fentanyl 2 mcg per kg bolus 30 minutes before induction followed by 2 mcg per kg per hr infusion for 90 minutes of surgery, and Group 2 patient belonging to fentanyl 1 mcg per kg bolus 30 minutes before induction followed by 1 mcg per kg per hr infusion for 90 minutes of surgery. The significance of the difference in quantitative measures was measured using the student-t test, and the Chi-square test was used to measure up the difference in proportion. Statistically significant was set at P<0.05. Results Mean systolic blood pressure was higher in members of Group 2 than in Group 1. In contrast to Group 2, Group 1 had considerably better surgical field conditions, surgeon satisfaction on the AONO'S scale, post-operative nausea and vomiting, and a post-operative VAS Score during the first 24 hours. Conclusion Pre-induction Fentanyl with infusion can effectively control hypotension during functional endoscopic sinus surgery.

Effect of continuous infusion of dexmedetomidine on blood loss in orthognathic surgery: a retrospective study

BACKGROUND

Patients with maxillofacial deformities require orthognathic surgeries to correct occlusion. The surgical procedure may lead to massive bleeding, which is associated with haematoma, respiratory obstruction, and asphyxia. Dexmedetomidine has been used in controlled hypotension and may reduce blood loss in orthognathic surgery. We conducted a retrospective cohort study to evaluate the effect of dexmedetomidine on blood loss in orthognathic surgeries.

METHODS

The primary outcome examined was blood loss, and secondary outcomes were postoperative haemoglobin level; intraoperative heart rate and blood pressure (T1: at incision; T2: 30 min after incision; T3: 60 min after incision; T4: 120 min after incision); dosage of fentanyl, remifentanil, urapidil, and esmolol; operation time; and incidence of allogeneic blood transfusion.

RESULTS

A total of 1247 patients were included in this study, and 540 patient pairs were matched via propensity score matching. There were significant decreases in mean blood loss, heart rate at T1-T4, blood pressure at T1, and remifentanil and esmolol dosage in the dexmedetomidine group compared with those in the control group. There was also a significant increase in the postoperative haemoglobin level of the dexmedetomidine group.

CONCLUSIONS

Continuous infusion of dexmedetomidine can decrease blood loss in orthognathic surgery.

TRIAL REGISTRATION

ChiCTR1800018794 (retrospectively registered) Name of registry: Chinese Clinical Trial Registry Date of registration: 2018/10/09 URL: www.chictr.org.cn/showproj.aspx?proj=30612.

Efficacy of Topical Epinephrine in Tympanoplasty

OBJECTIVES/HYPOTHESIS

To compare the hemostatic effects of commonly used concentrations of topical epinephrine in tympanoplasty.

STUDY DESIGN

Prospective, randomized, controlled clinical trial.

METHODS

Patients undergoing tympanoplasty were randomized to receive topical epinephrine at 1:1,000 or 1:10,000. With the investigators blinded, hemostasis was assessed with a modified Boezaart scale. Vasoconstriction was measured by laser Doppler. Blood pressure and pulse were tracked.

RESULTS

Thirty patients, 4 to 84 years old, were studied, with 15 patients per group. Boezaart scores dropped a mean of 67% and 62% with 1:1,000 and 1:10,000, respectively (P = .44). Capillary blood flow decreased a mean of 50.4% and 50.9% with 1:1,000 and 1:10,000, respectively (P = .95). The mean change in heart rate and mean arterial pressure after topical epinephrine exposure were -4.9 and -0.73 beats per minute (P = .15), and -0.60 and -0.73 mmHg (P = .96) for 1:1,000 and 1:10,000 respectively. No adverse events occurred in either group.

CONCLUSIONS

Topical epinephrine at 1:10,000 has hemostatic efficacy comparable to 1:1,000 in tympanoplasty. Although both concentrations appear safe, use of topical epinephrine 1:10,000 should be considered over 1:1,000 to minimize the potential for adverse events.

LEVEL OF EVIDENCE

2 Laryngoscope, 2021.

A prospective, randomised double-blind study on the anaesthetic effect of dexmedetomidine hydrochloride in brainstem tumour surgery

Context

Brainstem tumour surgery is difficult, and accidents can easily occur.

Objective

To explore the effect of dexmedetomidine hydrochloride on brainstem tumour surgery.

Design, setting and participants

A total of 60 patients with brainstem tumours successfully operated on by our hospital from March 2016 to March 2018 were selected as subjects.

Interventions

These patients were randomised into two groups: the research group (n = 30) and control group (n = 30). Patients in the control group were given propofol together with a placebo (0.9% sodium chloride solution) to maintain anaesthesia after general anaesthesia, while patients in the research group were supplemented with dexmedetomidine hydrochloride.

Main outcome measure

Awakening time, overall stability of various indicators in the operation and adverse reactions during the awakening period were observed.

Results

The results revealed that patients in the research group had a longer awakening time, higher mean stability rate, higher effective rate and less incidence of adverse reactions during the awakening period than the control group; the differences were all statistically significant (P < 0.05).

Conclusion

Dexmedetomidine hydrochloride has a good analgesic effect in intraoperative anaesthesia during brainstem tumour surgery, which significantly reduces the incidence of adverse reactions. Therefore, it can be used to assist anaesthesia during brainstem tumour operations and is worthy of clinical popularisation and application.

Comparison of surgical field visibility during propofol or desflurane anesthesia for middle ear microsurgery

Background

To compare surgical field visibility between patients given propofol/remifentanil (PR) or desflurane/remifentanil (DR) anesthesia.

Methods

A total of 80 adult patients undergoing middle ear microsurgery due to cholesteatoma otitis media with American Society of Anesthesiologists physical status I and II were randomly assigned to the PR or DR groups. The depth of anesthesia was titrated to maintain a Bispectral index (BIS) between 40 and 50. Remifentanil was titrated to maintain the mean blood pressure within ±30% change of the pre-induction value. Surgical field visibility was rated at several timepoints by the surgeons using the Boezaart scores.

Results

Average Boezaart scores for surgical field visibility at different time points were < 2 in both PR and DR groups. Surgical field visibility score was lower in the PR group than in the DR group. Requirement for remifentanil was higher in the PR group (850 (488/1330) μg) than in the DR group (258 (143/399) μg, P < 0.0001). The site effect concentration of remifentanil was higher in the PR group (3.6(2.8/5.0)ng/ml) than in the DR group (1.7 (1.0/1.6) ng/ml, P < 0.0001). Hemodynamic profile (i.e., heart rate and mean blood pressure) was similar between groups (P > 0.05). Extubation time (PR group, 21 min vs. DR group, 19 min; P = 0.199) and post-anesthesia care unit time (PR group, 37 min vs. DR group, 34 min; P = 0.324) were comparable between groups.

Conclusion

Although PR anesthesia resulted in lower surgical field visibility scores than DR anesthesia, both groups had scores < 2, meaning no clinical differences between the two groups. DR provided acceptable operative conditions as well, albeit more remifentanil consumption was noted in the DR group.

Trial registration

China Clinical Research Information Service, ChiCTR-1,800,015,537. Registered 5 April 2018. Date of enrolment of the first participant to the trial: 2 May 2018.

Comparing remifentanil, magnesium sulfate, and dexmedetomidine for intraoperative hypotension and bleeding and postoperative recovery in endoscopic sinus surgery and tympanomastoidectomy

The study aimed to compare remifentanil, magnesium sulfate, and dexmedetomidine for intraoperative hypotension, bleeding volume, and recovery time in endoscopic sinus surgery and tympanomastoidectomy (TM). A double-blind clinical trial enrolled the patients undergoing endoscopic nasal sinus surgery and TM at Amirkabir Hospital (Arak, Iran), who were randomly assigned into three groups dexmedetomidine (DEX), remifentanil (REM), and magnesium sulfate (MgSO₄) to which we intravenously administered 1 μg/kg DEX, an intravenous dose of 1 μg/kg REM, and 40 mg/kg of intravenous MgSO₄, respectively. The blood loss, blood pressure (BP), heart ratio (HR), oxygen saturation (SaO₂), and recovery time were recorded. Significant differences were found statistically in bleeding rates among all groups (P = 0.0001). The least amount of blood loss (very mild bleeding) was observed at 82.85% in the DEX group. BP and HR were lower in this group than those in the other groups. While recovery score was significantly different in the three groups (P = 0.007), the recovery time was the highest in the DEX group, while the least in the REM group. Based on the present results Dexmedetomidine seems to better prevent from bleeding than the others. Moreover, DEX can cause lower BP and HR in subjects with lower propofol administration, but the recovery time is longer. This study was registered by IRCT2017021114056N11 in Iranian Registry Clinical Center.

Alpha-2 adrenergic agonists for the prevention of cardiac complications among adults undergoing surgery

BACKGROUND

The surgical stress response plays an important role on the pathogenesis of perioperative cardiac complications. Alpha-2 adrenergic agonists attenuate this response and may help prevent postoperative cardiac complications.

OBJECTIVES

To determine the efficacy and safety of α-2 adrenergic agonists for reducing mortality and cardiac complications in adults undergoing cardiac surgery and non-cardiac surgery.

SEARCH METHODS

We searched CENTRAL (2017, Issue 4), MEDLINE (1950 to April Week 4, 2017), Embase (1980 to May 2017), the Science Citation Index, clinical trial registries, and reference lists of included articles.

SELECTION CRITERIA

We included randomized controlled trials that compared α-2 adrenergic agonists (i.e. clonidine, dexmedetomidine or mivazerol) against placebo or non-α-2 adrenergic agonists. Included trials had to evaluate the efficacy and safety of α-2 adrenergic agonists for preventing perioperative mortality or cardiac complications (or both), or measure one or more relevant outcomes (i.e. death, myocardial infarction, heart failure, acute stroke, supraventricular tachyarrhythmia and myocardial ischaemia).

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality, extracted data and independently performed computer entry of abstracted data. We contacted study authors for additional information. Adverse event data were gathered from the trials. We evaluated included studies using the Cochrane 'Risk of bias' tool, and the quality of the evidence underlying pooled treatment effects using GRADE methodology. Given the clinical heterogeneity between cardiac and non-cardiac surgery, we analysed these subgroups separately. We expressed treatment effects as pooled risk ratios (RR) with 95% confidence intervals (CI).

MAIN RESULTS

We included 47 trials with 17,039 participants. Of these studies, 24 trials only included participants undergoing cardiac surgery, 23 only included participants undergoing non-cardiac surgery and eight only included participants undergoing vascular surgery. The α-2 adrenergic agonist studied was clonidine in 21 trials, dexmedetomidine in 24 trials and mivazerol in two trials.In non-cardiac surgery, there was high quality evidence that α-2 adrenergic agonists led to a similar risk of all-cause mortality compared with control groups (1.3% with α-2 adrenergic agonists versus 1.7% with control; RR 0.80, 95% CI 0.61 to 1.04; participants = 14,081; studies = 16). Additionally, the risk of cardiac mortality was similar between treatment groups (0.8% with α-2 adrenergic agonists versus 1.0% with control; RR 0.86, 95% CI 0.60 to 1.23; participants = 12,525; studies = 5, high quality evidence). The risk of myocardial infarction was probably similar between treatment groups (RR 0.94, 95% CI 0.69 to 1.27; participants = 13,907; studies = 12, moderate quality evidence). There was no associated effect on the risk of stroke (RR 0.93, 95% CI 0.55 to 1.56; participants = 11,542; studies = 7; high quality evidence). Conversely, α-2 adrenergic agonists probably increase the risks of clinically significant bradycardia (RR 1.59, 95% CI 1.18 to 2.13; participants = 14,035; studies = 16) and hypotension (RR 1.24, 95% CI 1.03 to 1.48; participants = 13,738; studies = 15), based on moderate quality evidence.There was insufficient evidence to determine the effect of α-2 adrenergic agonists on all-cause mortality in cardiac surgery (RR 0.52, 95% CI 0.26 to 1.04; participants = 1947; studies = 16) and myocardial infarction (RR 1.01, 95% CI 0.43 to 2.40; participants = 782; studies = 8), based on moderate quality evidence. There was one cardiac death in the clonidine arm of a study of 22 participants. Based on very limited data, α-2 adrenergic agonists may have reduced the risk of stroke (RR 0.37, 95% CI 0.15 to 0.93; participants = 1175; studies = 7; outcome events = 18; low quality evidence). Conversely, α-2 adrenergic agonists increased the risk of bradycardia from 6.4% to 12.0% (RR 1.88, 95% CI 1.35 to 2.62; participants = 1477; studies = 10; moderate quality evidence), but their effect on hypotension was uncertain (RR 1.19, 95% CI 0.87 to 1.64; participants = 1413; studies = 9; low quality evidence).These results were qualitatively unchanged in subgroup analyses and sensitivity analyses.

AUTHORS' CONCLUSIONS

Our review concludes that prophylactic α-2 adrenergic agonists generally do not prevent perioperative death or major cardiac complications. For non-cardiac surgery, there is moderate-to-high quality evidence that these agents do not prevent death, myocardial infarction or stroke. Conversely, there is moderate quality evidence that these agents have important adverse effects, namely increased risks of hypotension and bradycardia. For cardiac surgery, there is moderate quality evidence that α-2 adrenergic agonists have no effect on the risk of mortality or myocardial infarction, and that they increase the risk of bradycardia. The quality of evidence was inadequate to draw conclusions regarding the effects of alpha-2 agonists on stroke or hypotension during cardiac surgery.

Controlled Hypotension During Rhinoplasty: A Comparison of Dexmedetomidine with Magnesium Sulfate

Objective

The current study aimed at comparing the efficacy of dexmedetomidine and magnesium sulfate to control blood pressure (BP) during rhinoplasty and the resultant effects on the quality of surgical field in terms of bleeding and visibility.

Methods

The current randomized, prospective, double-blind study was conducted on 60 patients aged 18 to 50 years classified as ASA (American Society of Anesthesiologists) physical status I who were candidates for rhinoplasty. Patients were randomly divided into 2 groups: (1) group Dex, received 1 µg/kg dexmedetomidine in 10 minutes before induction of anesthesia, followed by 0.4 - 0.6 µg/kg/hour during the maintenance of anesthesia, and (2) group Mg, received 40 mg/kg in 10 minutes before anesthesia induction followed by 10 - 15 mg/kg/hour during anesthesia maintenance. In both groups, the goal was to achieve a mean arterial pressure (MAP) of 60 - 70 mmHg. Hemodynamic variables, anesthetic, opioid, muscle relaxant requirements, and surgical field condition were recorded. Sedation score, time to reach modified Aldrete score ≥ 9, and adverse effects including nausea and vomiting (N&V) and shivering were recorded.

Results

Controlled hypotension was achieved in both groups. There was no significant difference in MAP between the groups, but heart rate (HR) was significantly lower in the Dex group (P < 0.001), compared with that of the Mg group. Bleeding score was lower (P < 0.001) and surgeon's satisfaction score was higher (P < 0.001) in the Dex group. More patients required fentanyl (P < 0.001) or nitroglycerin (P < 0.001) and the mean fentanyl (P = 0.005) or nitroglycerin (P < 0.001) required doses were higher in the Mg group. Patients in the Dex group required more frequent administration of cisatracurium (P = 0.004). Five patients in the Dex group versus no patients in the Mg group received atropine (P = 0.023). Ramsay sedation score and time to reach modified Aldrete score ≥ 9 were significantly higher in the Dex group (P < 0.001 and P < 0.001, respectively). The incidence rate of N&V and shivering were similar in both groups.

Conclusion

Dexmedetomidine was more effective than magnesium to achieve controlled hypotension, and provide a favorable surgical field condition. However, dexmedetomidine also heightened the risk of induced bradycardia and prolonged sedation. These are 2 important points to consider when applying this drug as a hypotensive agent during operation.

A Study to Compare the Quality of Surgical Field Using Total Intravenous Anesthesia (with Propofol) versus Inhalational Anesthesia (with Isoflurane) for Functional Endoscopic Sinus Surgeries

Background and Objectives:

Functional endoscopic sinus surgery (FESS) being a delicate technique, intraoperative bleeding is one of the major challenges. Even a little bleeding can adversely affect the surgeon's ability to visualize the region to be operated. General anesthesia is preferred over topical anesthesia in FESS. This study was conducted to compare the surgical field using total intravenous anesthesia (TIVA) with propofol and inhalational anesthesia with isoflurane for FESS. Secondary outcomes such as intraoperative blood loss and the incidence of perioperative complications were also recorded.

Subjects and Methods:

A total of sixty patients in the age group of 16–60 years with physical status American Society of Anesthesiologists Classes I and II, undergoing FESS were randomly divided into two groups of thirty each after taking informed consent and approval from the Hospital Ethics Committee. Thirty patients in Group I: received isoflurane-based inhalational anesthesia and other Thirty patients in Group II: were administered TIVA with propofol. Various parameters were recorded and statistically analyzed.

Results:

There was improved quality of surgical field at the end of surgery in the Group II as compared to Group I. Total blood loss during surgery and incidence of intraoperative complications were less in Group II as compared to Group I.

Conclusion:

This study concludes that in FESS, using TIVA with propofol decreases blood loss and the incidence of complications during surgery in addition to providing good quality of surgical field.

Dexmedetomidine infusion as an anesthetic adjuvant to general anesthesia for appropriate surgical field visibility during modified radical mastectomy with i-gel®: a randomized control study

Background

Modified radical mastectomy is associated with appreciable blood loss, while endotracheal intubation leads to elevated hemodynamic responses. The present study aimed to evaluate the clinical efficacy of dexmedetomidine infusion as an anesthetic adjuvant to general anesthesia during modified radical mastectomy with I-Gel.

Methods

Sixty adult consenting female patients, of American Society of Anesthesiologists physical status 1 to 2 and aged 4,065 years, were blindly randomized into two groups of 30 patients each. The patients in Group I received intravenous dexmedetomidine at a loading dose of 1 µg/kg over 10 min, followed by maintenance infusion of 0.4 to 0.7 µg/kg/h, while patients in Group II were administered an identical amount of saline infusion until 15 min prior to the end of surgery. The primary end point was bleeding at the surgical field and hemodynamic changes; requirement of isoflurane, intraoperative fentanyl consumption and recovery time were assessed as secondary outcomes.

Results

The patients receiving dexmedetomidine infusion showed significantly less bleeding at the surgical field (P < 0.05). A statistically significant reduction was also observed in the percentage of isoflurane required (0.82 ± 0.80%) to maintain the systolic blood pressure between 100 and 110 mmHg in patients receiving dexmedetomidine infusion compared with the Group II (1.50 ± 0.90%). The mean intraoperative fentanyl consumption in patients in the Group I was also significantly lower compared with that of the Group II (38.43 ± 5.40 µg vs. 75.12 ± 4.60 µg). The mean recovery time from anesthesia did not show any clinically significant difference between the groups.

Conclusions

Dexmedetomidine infusion can be used safely to decrease the bleeding at the surgical field with smooth recovery from anesthesia.

Surgical conditions during FESS; comparison of dexmedetomidine and remifentanil

To compare dexmedetomidine with remifentanil in functional endoscopic sinus surgery (FESS) in regards to intra-operative bleeding, anesthetic consumption and post-operative recovery. Randomized, double blind study. Tertiary care medical center. Fifty patients with nasal polyposis who had been scheduled for FESS were randomly divided into two groups. In group D (n = 25), dexmedetomidine 1 µg/kg infused intravenous (IV) over 10 min before anesthesia induction, followed by a continuous of 0.7 µg/kg/h infusion during operation. In group R (n = 25), 1 µg/kg remifentanil IV bolus, was administered with induction of anesthesia and continued 0.25-0.50 µg/kg/min during operation. Heart rates, mean arterial pressure, end tidal CO₂, end tidal sevoflurane were recorded. The amount of bleeding, surgical field condition for bleeding and the time to reach Aldrete recovery score 9-10 were recorded. Postoperative nausea, vomiting, pain, shivering, sedation were followed up over 24 h. There was no significant difference between groups according to the amount of bleeding during surgery, assessment of surgical field condition, consumption of sevoflurane, scores of postoperative VAS, rates of nausea and vomiting, shivering, demands of additional analgesic medication (P > 0.05). The time to reach Aldrete recovery score 9-10, sedation scores at the postoperative first hour were significantly higher in group D (P = 0.001). We concluded that in comparison to remifentanil, dexmedetomidine during FESS for controlled hypotension is of limited value as it has no additional benefits in terms of control of hypotension and amount of bleeding in the surgical field and it is associated with higher recovery time and first-hour postoperative sedation scores.

Nitroglycerine, esmolol and dexmedetomidine for induced hypotension during functional endoscopic sinus surgery: A comparative evaluation

Background and Aim:

Induced hypotension limits intra-operative blood loss to provide better visibility of the surgical field and diminishes the incidence of major complications during functional endoscopic sinus surgery (FESS). We aimed at comparing nitroglycerine, esmolol and dexmedetomidine for inducing controlled hypotension in patients undergoing FESS.

Material and Methods:

One hundred and fifty American Society of Anesthesiologists physical status I or II adult patients undergoing FESS under general anesthesia were randomly allocated to three groups of 50 patients each. Group E received esmolol in a loading and maintenance dose of 1 mg/kg over 1 min and 0.5-1.0 mg/kg/h, respectively. Group D received a loading dose of dexmedetomidine 1 μg/kg over 10 min followed by an infusion 0.5-1.0 μg/kg/h, and group N received nitroglycerine infusion at a dose of 0.5-2 μg/kg/min so as to maintain mean arterial pressure (MAP) between 60 and 70 mmHg in all the groups. The visibility of the surgical field was assessed by surgeon using Fromme and Boezaart scoring system. Hemodynamic variables, total intra-operative fentanyl consumption, emergence time and time to first analgesic request were recorded. Any side-effects were noted. The postoperative sedation was assessed using Ramsay Sedation Score.

Result:

The desired MAP (60-70 mmHg) could be achieved in all the three study groups albeit with titration of study drugs during intra-operative period. No significant intergroup difference was observed in Fromme's score during the intra-operative period. The mean total dose of fentanyl (μg/kg) used was found to be significantly lower in group D compared to groups E and N (1.2 ± 0.75 vs. 3.6 ± 1.3 and 2.9 ± 1.1 respectively). The mean heart rate was significantly lower in group D compared to groups E and N at all times of measurement (P < 0.05). The MAP was found to be significantly lower in group D compared to groups E and N after infusion of study drugs, after induction, just after intubation and 5 min after intubation (P < 0.05). The Ramsay Sedation Scores were significantly higher in group D (score 3 in 46%) when compared to group E (score 2 in 50%) and group N (score 2 in 54%) (P < 0.001). The emergence time was significantly lower in group E and group N compared to group D. Time to first analgesic request was significantly longer in group D.

Conclusion:

Dexmedetomidine and esmolol provided better hemodynamic stability and operative field visibility compared to nitroglycerin during FESS. Dexmedetomidine provides an additional benefit of reducing the analgesic requirements and providing postoperative sedation.

[Comparison between magnesium sulfate and dexmedetomidine in controlled hypotension during functional endoscopic sinus surgery]

BACKGROUND AND OBJECTIVES

It is crucial to decrease bleeding during functional endoscopic sinus surgery. Our primary goal was to investigate the effects of magnesium sulfate and dexmedetomidine used for controlled hypotension on the visibility of the surgical site.

METHODS

60 patients aged between 18 and 65 years were enrolled. In the magnesium sulfate group (Group M), patients were administered 40mg/kg magnesium sulfate in 100mL saline solution over 10min as the intravenous loading dose 10min before induction, with a subsequent 10-15mg/kg/h infusion during surgery. In the dexmedetomidine group (Group D), patients were administered 1μg/kg dexmedetomidine in 100mL saline solution as the loading dose 10min before surgery and 0.5-1μg/kg/h dexmedetomidine during surgery. Deliberate hypotension was defined as a mean arterial pressure of 60-70mmHg.

RESULTS

Bleeding score was significantly decreased in Group D (p=0.002). Mean arterial pressure values were significantly decreased in Group D compared to that in Group M, except for the initial stage, after induction and 5min after intubation (p<0.05). The number of patients who required nitroglycerine was significantly lower in Group D (p=0.01) and surgeon satisfaction was significantly increased in the same group (p=0.001). Aldrete recovery score ≥9 duration was significantly shorter in Group D (p=0.001). There was no difference between the two groups in terms of recovery room verbal numerical rating scale.

CONCLUSIONS

Dexmedetomidine can provide more effective controlled hypotension and thus contribute to improved visibility of the surgical site.

[Comparison of the effects of magnesium sulphate and dexmedetomidine on surgical vision quality in endoscopic sinus surgery: randomized clinical study]

BACKGROUND AND OBJECTIVES

Even a small amount of bleeding during endoscopic sinus surgery can corrupt the endoscopic field and complicate the procedure. Various techniques, including induced hypotension, can minimize bleeding during endoscopic sinus surgery. The aim of this study was to compare the surgical vision quality, haemodynamic parameters, postoperative pain, and other effects of magnesium, a hypotensive agent, with that of dexmedetomidine, which was initially developed for short-term sedation in the intensive care unit but also is an alpha 2 agonist sedative.

METHOD

60 patients between the ages of 18 and 45 years were divided into either the magnesium group (Group M) or the dexmedetomidine group (Group D). In Group M, magnesium sulphate was given at a pre-induction loading dose of 50mgkg(-1) over 10min and maintained at 15mgkg(-1)h(-1); in Group D, dexmedetomidine was given at 1mcgkg(-1) 10min before induction and maintained at 0.6mcgkg(-1)h(-1). Intraoperatively, the haemodynamic and respiratory parameters and 6-point intraoperative surgical field evaluation scale were recorded. During the postoperative period, an 11-point numerical pain scale, the Ramsay sedation scale, the nausea/vomiting scale, the adverse effects profile, and itching parameters were noted.

RESULTS

Group D showed a significant decrease in intraoperative surgical field evaluation scale scale score and heart rate. The average operation time was 50min, and Group M had a higher number of prolonged surgeries. No significant difference was found in the other parameters.

CONCLUSIONS

Due to its reduction of bleeding and heart rate in endoscopic sinus surgery and its positive impacts on the duration of surgery, we consider dexmedetomidine to be a good alternative to magnesium.

Comparison of the hemodynamic effects of nitroprusside and remifentanil for controlled hypotension during endoscopic sinus surgery

PURPOSE

Controlled hypotension (CH) is a well-established technique to decrease blood loss and improve surgical visibility. Although nitroprusside and remifentanil have been safely and effectively used for this purpose, the hemodynamic changes that occur during CH are unclear. This study compared the effects of nitroprusside and remifentanil on hemodynamics using a noninvasive cardiac output monitor (Cheetah NICOM(®); Cheetah Medical Inc., Maidenhead, Berkshire, UK) for endoscopic sinus surgery (ESS).

METHODS

Twenty-eight adult patients scheduled for ESS were randomly assigned to the nitroprusside group (n = 14) or remifentanil group (n = 14). After anesthesia induction, hypotension was induced with continuous infusion of nitroprusside or remifentanil at a target mean arterial blood pressure (MAP) of 60-70 mmHg. Cardiac index (CI), stroke volume index (SVI) and total peripheral resistance index (TPRI) were measured at 10-min intervals.

RESULTS

The heart rate was higher and SVI was lower in the nitroprusside group than in the remifentanil group during CH. There were no significant differences in MAP, CI or TPRI between the two groups. Both nitroprusside and remifentanil reduced MAP and TPRI during CH compared with baseline values. However, there was no significant change in CI.

CONCLUSIONS

Both nitroprusside and remifentanil were effective to induce CH and maintain CI during CH.

Controlled hypotension with desflurane combined with esmolol or dexmedetomidine during tympanoplasty in adults: A double-blind, randomized, controlled trial

BACKGROUND

Controlled hypotension is a technique that is used to limit intraoperative blood loss to provide the best possible surgical field during surgery.

OBJECTIVE

The aim of this double-blind, randomized, controlled study was to compare the effects of desflurane combined with esmolol or dexmedetomidine on the amount of blood in the surgical field, recovery time, and tolerability in adult patients undergoing tympanoplasty.

METHODS

Turkish patients aged 18 to 60 years, classified as American Society of Anesthesiologists physical status I or II, who were scheduled for tympanoplasty were randomly divided into 2 groups: the esmolol group or the dexmedetomidine group. After the anesthesia induction in the esmolol group, a loading dose of esmolol was infused intravenously over 1 minute at 1 mg/kg, followed by a maintenance rate of 0.4 to 0.8 mg/ kg/h. In the dexmedetomidine group, a loading dose of dexmedetomidine was infused intravenously over 10 minutes at a rate of 1 μg/kg, followed by a maintenance rate of 0.4 to 0.8 μg/kg/h. The infusion rates were then titrated to maintain mean arterial pressure (MAP) of 65 to 75 mm Hg. General anesthesia was maintained with desflurane 4% to 6%. Heart rate (HR) and MAP were recorded during anesthesia. The following 6-point scale was used to assess the amount of bleeding in the operative field: 0 = no bleeding, a virtually bloodless field; 1 = bleeding that was so mild that it was not a surgical nuisance; 2 = moderate bleeding that was a nuisance but did not interfere with accurate dissection; 3 = moderate bleeding that moderately compromised surgical dissection; 4 = bleeding that was heavy but controllable and that significantly interfered with surgical dissection; and 5 = massive bleeding that was uncontrollable and made dissection impossible. Scores ≤2 were considered to be optimal surgical conditions. The sedation score was determined at 15, 30, and 60 minutes after tracheal extubation using the following scale: 1 = anxious, agitated, or restless; 2 = cooperative, oriented, and tranquil; 3 = responsive to commands; 4 = asleep, but with brisk response to light, glabellar tap, or loud auditory stimulus; 5 = asleep, sluggish response to glabellar tap or auditory stimulus; and 6 = asleep, no response. Time to extubation and to total recovery from anesthesia (Aldrete score ≥9 on a scale of 0-10), adverse effects (eg, intraoperative hypotension [blood pressure <65 mm Hg], bradycardia [HR <50 beats/min]), intraoperative fentanyl consumption, and postoperative nausea and vomiting were recorded. Arterial blood gas analysis and kidney and liver function tests were conducted. All patients were evaluated by the same attending surgeon and anesthesiologist, both of whom were blinded to the administered study drugs.

RESULTS

Fifty-two consecutive white patients undergoing tympanoplasty were identified. Two patients had to be excluded because of hypertension and 2 refused to participate. Forty-eight patients were equally randomized to either the esmolol group (n = 24 [16 women, 8 men]; mean [SD] age, 38.4 [10.5] years) or the dexmedetomi-dine group (n = 24 [17 women, 7 men]; mean age, 35.5 [14.7] years). Sedation scores were not collected for 1 patient in the esmolol group; therefore, analysis was conducted for 23 patients. The median (range) of the scores for the amount of blood in the surgical field in the esmolol and dexmedetomidine groups was 1 (0-3) and 1 (0-2), respectively (P = NS). Mean intraoperative fentanyl consumption in the esmolol group was significantly higher than in the dexmedetomidine group (50.0 [3.0] vs 25.0 [2.5] μg/min; P = 0.002). In the esmolol group, the mean times to extubation and to recovery from anesthesia were significantly shorter than those of the dexmedetomidine group (7.0 [1.4] vs 9.1 [1.9] minutes, respectively; 5.9 [2.1] vs 7.9 [2.3] minutes; both, P = 0.001). The mean sedation scores were significantly lower in the esmolol group (n = 23, because of intent-to-treat analysis) compared with the dexmedetomidine group at 15 minutes (2.5 [0.6] vs 3.6 [0.5]; P = 0.001) and 30 minutes (2.6 [0.6] vs 3.3 [0.6]; P = 0.001) postoperatively. No significant differences were found between the study groups in regard to blood urea nitrogen or creatinine concentration, aspartate aminotransferase or alanine aminotransferase activities, pH, partial pressure of carbon dioxide, or bicarbonate, before or after the operation.

CONCLUSIONS

Both esmolol and dexmedetomidine, combined with desflurane, provided an effective and well-tolerated method of achieving controlled hypotension to limit the amount of blood in the surgical field in these adult patients undergoing tympanoplasty. Esmolol was associated with significantly shorter extubation and recovery times and significantly less postoperative sedation compared with dexmedetomidine.

Heart rate variability dynamics during controlled hypotension with nicardipine, remifentanil and dexmedetomidine

BACKGROUND

This study was done to investigate how nicardipine, remifentanil and dexmedetomidine affect the balance of the autonomic nervous system in patients receiving controlled hypotension under general anaesthesia by evaluating heart rate variability indices.

METHODS

Sixty-two patients were randomly allocated to either the nicardipine-sevoflurane (Group N, n = 21), remifentanil-sevoflurane (Group R, n = 21) or dexmedetomidine-sevoflurane (Group D, n = 20) group for controlled hypotension during orthognathic surgery. Electrocardiogram data acquisition was done after vital sign stabilization following anaesthesia induction (T1) and 30 min after controlled hypotension was induced (T2).

RESULTS

Total power and low frequency (LF) power was significantly decreased at T2 compared with T1 in all groups, while a decrease in high frequency (HF) power was only observed in Group N (P < 0.001). LF/HF ratios of Group R and D were significantly suppressed at T2 compared with T1 (P = 0.001 and P < 0.001, respectively), but was increased Group N (P = 0.009). The LF/HF ratio of Group N was significantly higher than Group R and D at T2 (P < 0.001 in both), with Group D showing a significantly lower LF/HF ratio compared with Group R (P < 0.001).

CONCLUSIONS

Remifentanil and dexmedetomidine did not have sympathetic nervous system-stimulating effects during controlled hypotension, while remifentanil seemed to be superior in preserving the overall balance in autonomic nervous system activity. Nicardipine was found to stimulate the sympathetic nervous system, which may be problematic in patients vulnerable to disturbances in the autonomic nervous system.

Induced hypotension for functional endoscopic sinus surgery: A comparative study of dexmedetomidine versus esmolol

OBJECTIVE

A comparative study to evaluate the efficacy of dexmedetomidine as a hypotensive agent in comparison to esmolol in Functional Endoscopic Sinus Surgery (FESS).

METHODS

Forty patients ASA I or II scheduled for FESS were equally randomly assigned to receive either dexmedetomidine 1 μg/Kg over 10 min before induction of anesthesia followed by 0.4-0.8 μg/Kg/h infusion during maintenance (DEX group), or esmolol, loading dose 1mg/kg was infused over one min followed by 0.4-0.8 mg/kg/h infusion during maintenance (E group) to maintain mean arterial blood pressure (MAP) between (55-65 mmHg). General anesthesia was maintained with sevoflurane 2%-4%. The surgical field was assessed using Average Category Scale and average blood loss was calculated. Hemodynamic variables (MAP and HR); arterial blood gas analysis; plasma cortisol level; intraoperative fentanyl consumption; Emergence time and total recovery from anesthesia (Aldrete score ≥9) were recorded. Sedation score was determined at 15, 30, 60 min after tracheal extubation and time to first analgesic request was recorded.

RESULT

Both DEX group and E group reached the desired MAP (55-65 mmHg) with no intergroup differences in MAP or HR. The for the quality of the surgical filed in the range of MAP (55-65 mmHg) were <=2 with no significant differences between group scores during hypotensive period. Mean intraoperative fentanyl consumption was significantly lower in DEX group than E group. Cortisol level showed no significant changes between or within groups. No significant changes were observed in arterial blood gases. Emergence time and time to achieve Aldrete score ≥9 were significantly lower in E group compared with DEX group. The sedation score were significantly lower in E group compared with DEX group at 15 and 30 minutes postoperatively. Time to first analgesic request was significantly longer in DEX group.

CONCLUSION

Both dexmedetomidine or esmolol with sevoflurane are safe agents for controlled hypotension and are effective in providing ideal surgical field during FESS. Compared with esmolol, dexmedetomidine offers the advantage of inherent analgesic, sedative and anesthetic sparing effect.

Review of anesthesia for middle ear surgery

Special considerations for middle ear surgery include a bloodless surgical field, attention to patient head positioning, facial nerve monitoring, and management of postoperative nausea and vomiting. Middle ear surgery can be done under local or general anesthesia; each has advantages and disadvantages.

Alpha-2 adrenergic agonists for the prevention of cardiac complications among patients undergoing surgery

BACKGROUND

The surgical stress response plays an important role on the pathogenesis of perioperative cardiac complications. Alpha-2 adrenergic agonists attenuate this response and may thereby prevent cardiac complications.

OBJECTIVES

This review assessed the efficacy and safety of preoperative (within 24 hours), intraoperative, and postoperative (first 48 hours) alpha-2 adrenergic agonists for preventing mortality and cardiac complications after surgery performed under either general or neuraxial anaesthesia, or both.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 3), MEDLINE (1950 to August week 4 2008), EMBASE (1980 to week 36 2008), the Science Citation Index, and reference lists of articles.

SELECTION CRITERIA

We included randomized controlled trials that compared alpha-2 adrenergic agonists (clonidine, dexmedetomidine, or mivazerol) against placebo or non-alpha-2 adrenergic agonists. Included studies had to report on mortality, myocardial infarction, myocardial ischaemia, or supraventricular tachyarrhythmia.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trial quality and extracted data. Two authors independently performed computer entry of abstracted data. We contacted study authors for additional information. Adverse event data were gathered from the trials.

MAIN RESULTS

We included 31 studies (4578 participants). Study quality was generally inadequate, with only six studies clearly reporting methods for blinding and allocation concealment. Overall, alpha-2 adrenergic agonists reduced mortality (relative risk (RR) 0.66; 95% CI 0.44 to 0.98; P = 0.04) and myocardial ischaemia (RR 0.68; 95% CI 0.57 to 0.81; P < 0.0001). However, their effects appeared to vary with the surgical procedure. The most encouraging data pertained to vascular surgery, where they reduced mortality (RR 0.47; 95% CI 0.25 to 0.90; P = 0.02), cardiac mortality (RR 0.36; 95% CI 0.16 to 0.79; P = 0.01), and myocardial infarction (RR 0.66; 95% CI 0.46 to 0.94; P = 0.02). With regard to adverse effects, alpha-2 adrenergic agonists significantly increased perioperative hypotension (RR 1.32; 95% CI 1.07 to 1.62; P = 0.009) and bradycardia (RR 1.66; 95% CI 1.14 to 2.41; P = 0.008).

AUTHORS' CONCLUSIONS

Our study provides encouraging evidence that alpha-2 adrenergic agonists may reduce cardiac risk, especially during vascular surgery. Nonetheless, these data remain insufficient to make firm conclusions about their efficacy and safety. A large randomized trial of alpha-2 adrenergic agonists is therefore warranted. Additionally, future research must determine which specific alpha-2 adrenergic agonist should be used, and whether it is safe to combine them with other perioperative interventions (for example beta-adrenergic blockade).

Controlled hypotension for middle ear surgery: a comparison between remifentanil and magnesium sulphate

BACKGROUND

This prospective, randomized study was designed to compare remifentanil and magnesium sulphate during middle ear surgery in terms of postoperative pain and other complications.

METHODS

Eighty patients undergoing middle ear surgery were enrolled in the study. Patients were randomized into two groups of 40 to receive remifentanil (Group R) or magnesium sulphate (Group M) infusion. Propofol 2 mg kg(-1) was administered to induce anaesthesia, which was maintained using sevoflurane. Group R received a continuous infusion of remifentanil titrated between 3 and 4 ng ml(-1) using target-controlled infusion, whereas Group M received an i.v. magnesium sulphate bolus of 50 mg kg(-1) followed by a 15 mg kg(-1) h(-1) continuous infusion to maintain a mean arterial pressure (MAP) between 60 and 70 mm Hg. Haemodynamic variables, surgical conditions, postoperative pain, and adverse effects, such as postoperative nausea and vomiting (PONV) and shivering, were recorded.

RESULTS

Controlled hypotension was well maintained in both groups. MAP and heart rate were higher in Group R than in Group M after operation. Surgical conditions were not different between the two groups. Postoperative pain scores were significantly lower in Group M than in Group R (P<0.05). Seventeen patients in Group R (43%) and seven patients in Group M (18%) developed PONV (P=0.01).

CONCLUSIONS

Both magnesium sulphate and remifentanil when combined with sevoflurane provided adequate controlled hypotension and proper surgical conditions for middle ear surgery. However, patients administered magnesium sulphate had a more favourable postoperative course with better analgesia and less shivering and PONV.