The effects of dexmedetomidine and magnesium sulphate in adult patients undergoing endoscopic transnasal transsphenoidal resection of pituitary adenoma: A double-blind randomised study

A prospective-randomized placebo-controlled trial comparing the effects of nebulized dexmedetomidine v/s dexmedetomidine-lignocaine mixture on intraoperative hemodynamics and surgical field quality in patients undergoing endoscopic transnasal transsphenoidal pituitary tumor surgery

Background

During transnasal transsphenoidal pituitary surgery (TNTSS), the primary objective is to maintain stable hemodynamics while ensuring ideal surgical conditions. This study aimed to investigate the effect of nebulized dexmedetomidine on hemodynamic parameters and the quality of the surgical field during TNTSS.

Methods

Seventy-five patients scheduled for TNTSS were randomized into three groups of 25 each and received preoperative nebulization with 5 mL of nebulizing fluid consisting of 1.5 μg/kg of dexmedetomidine with saline in dexmedetomidine (D) group; 1.5 μg/kg of dexmedetomidine with 2% lignocaine in dexmedetomidine-lignocaine (DL) group and normal saline in the control (S) group. Heart rate (HR), mean blood pressure, Formmers score, anesthetic requirement, and emergence were evaluated for each group.

Results

Group S had significantly higher HR and mean arterial pressure than the other two groups across various time points during surgery (P < 0.01). The total requirements for fentanyl, propofol, sevoflurane, and labetalol and the incidence of delayed emergence were significantly higher in the S group compared to the other two groups (P < 0.01). The D and DL groups exhibited significantly better surgical field conditions than the S group. In all the parameters assessed, patients in the D group outperformed those in the DL group.

Conclusion

The administration of nebulized dexmedetomidine, both alone and in combination with lignocaine, resulted in stable hemodynamics, favorable operative conditions, reduced anesthetic requirement, and facilitated prompt emergence during TNTSS. Nebulized dexmedetomidine proved superior to its combination with lignocaine across all evaluated parameters.

Effects of Low versus Intermediate Doses of Dexmedetomidine Infusion on Blood Loss, Hemodynamics, and Operative Time in Transsphenoidal Pituitary Tumor Removal: A Prospective Randomized Study

Background Dexmedetomidine, an alpha-2 agonist, has been widely used as an anesthetic adjunct for transsphenoidal pituitary resection. However, there is no consensus on the appropriate infusion dosage. This study aimed to compare the effects of low (0.2 mcg/kg/h) and intermediate (0.5 mcg/kg/h) dexmedetomidine infusions during anesthetic maintenance on blood loss, hemodynamics, and operating time.

Methods A randomized controlled trial involving two centers was conducted. Between December 2015 and November 2019, 80 patients (40 in each group) who underwent elective transsphenoidal pituitary tumor resection were recruited. Dexmedetomidine was administered to group I at a loading dose of 0.5 mcg/kg, followed by 0.2 mcg/kg/h, and to group II at the same loading dose, followed by 0.5 mcg/kg/h. Comparative analyses were performed using the Student's t-test, repeated-measures analysis of variance, and Mann–Whitney U test; p-values < 0.05 were considered statistically significant.

Results Eighty patients were analyzed. Patient demographics were comparable. The difference in intraoperative blood loss between both groups (320 [220–525] vs. 250 [100-487] mL, p = 0.070) was not statistically significant. There were no differences in blood pressure or heart rate between the groups. In group II, the procedure took significantly less time (179 vs. 142 minutes, p = 0.018), with more episodes of transient hypotension (p = 0.034).

Conclusion When maintaining anesthesia for transsphenoidal pituitary resection, dexmedetomidine infusions of 0.2 and 0.5 mcg/kg/h showed the same effect on blood loss and hemodynamics; however, significantly more episodes of transient hypotension and shorter operating times were noted with the latter.

Effects of Magnesium Sulfate on Intraoperative Blood Loss and Anesthetic Requirement in Meningioma Patients Undergoing Craniotomy with Tumor Removal: A Prospective Randomized Study

Background Meningioma brain tumor is associated with significant blood loss. Magnesium (Mg), a calcium blocker, can facilitate blood pressure control during surgery. This study aimed to evaluate effects of magnesium on blood loss, anesthetic requirement, and its neuroprotective effect in meningioma patients undergoing craniotomy.

Methods Eighty patients aged between 18 and 70, American Society of Anesthesiologists physical status I and II, diagnosed with meningioma and scheduled for craniotomy tumor removal were randomized into two groups. Group M (Mg) received intravenous magnesium sulfate 40 mg/kg over 30 minutes initiated at skin incision and followed by continuous infusion of 10 mg/kg/h until dura closure. Group N (NSS) received 0.9% NaCl as placebo. Anesthesiologists in charge, surgeons, and patients were all blinded. The assessed outcomes were perioperative blood loss, anesthetic requirement, and pre- and postoperative neurocognitive functions assessed by Montreal Cognitive Assessment (MoCA).

Results Thirty-eight patients in each group were analyzed. In group M, the intraoperative blood losses were 500 (70, 2300) mL, and 510 (100, 1600) mL in group N (p = 0.315). Patients who received blood within 24 hours were 39.5% in group M and 47.4% in group N (p = 0.644). No differences were observed in anesthetic requirement, intraoperative mean arterial pressure, hypotensive episodes, and vasopressor usages. There were no significant differences in postoperative MoCA score. Magnesium levels did not exceed acceptable levels.

Conclusions Magnesium administration in meningioma patients had no significant effects on blood loss, anesthetic requirement, and postoperative cognitive function.

Comparison of hypotensive properties of dexmedetomidine versus clonidine for induced hypotension during functional endoscopic sinus surgery: A randomised, double-blind interventional study

Background and Aims

Excessive bleeding is a major concern in functional endoscopic sinus surgery (FESS) under general anaesthesia; this can be decreased by various hypotensive agents. This study was conducted to compare the hypotensive effectiveness and haemodynamic stability of dexmedetomidine and clonidine in patients undergoing elective FESS.

Methods

In this prospective double-blinded interventional study, 70 adult patients of either sex, 20-50 years of age, posted for elective FESS were randomly assigned to two groups. Group A received a loading dose of intravenous (IV) dexmedetomidine 1 μg/kg, followed by infusion of 1 μg/kg/h, and group B received a loading dose of IV clonidine 2 μg/kg, followed by 1 μg/kg/h infusion. Surgical field quality, emergence time, sedation score, visual analogue score, recovery profile and haemodynamic parameters were recorded. Statistical analysis was done by Student's unpaired t-test to evaluate the significance of normally distributed variables, whereas Mann-Whitney test and Chi-square test were used for ordinal data and categorical variables and proportions, respectively.

Results

In both the groups, target mean arterial pressure (MAP) of 65-70 mmHg and improved surgical field quality were achieved. MAP and heart rate (HR) were statistically significantly lower in the dexmedetomidine group with a longer duration of post-operative analgesia (P = 0.001). None of the groups showed any statistically significant adverse effects.

Conclusions

Both dexmedetomidine and clonidine can be used for controlled hypotension to improve surgical field quality in FESS. Dexmedetomidine provides more haemodynamic stability and an additional benefit of post-operative analgesia and conscious sedation.

Control of Hemodynamic Responses and Perioperative Outcomes in Transsphenoidal Pituitary Surgery: A Qualitative Systematic Review of the Available Evidence

Transnasal transsphenoidal (TNTS) pituitary surgery is associated with short-lived but intense nociceptive stimuli which cause substantial hemodynamic perturbations that may increase blood loss and impair visualization of the surgical field. This systematic review aimed to critically appraise the clinical evidence for the efficacy and safety of various anesthetic techniques, other pharmacological modalities, and supplementary interventions by assessing intraoperative systemic hemodynamics, use of adjunct medications, quality of the surgical field, intraoperative blood loss, and recovery profiles in patients undergoing TNTS pituitary surgery. Relevant randomized clinical trials and observational studies were identified in a systematic literature search; 16 studies (13 randomized clinical trials, 3 observational studies) enrolling a total of 907 patients were identified for inclusion in this review. Propofol provided more potent hemodynamic control compared with volatile anesthetics with a sparing effect on the need for additional drugs to blunt hemodynamic responses. Recovery profiles between propofol and sevoflurane were either equivalent or favored sevoflurane, but both agents were superior to isoflurane. Regarding intraoperative analgesia, remifentanil was associated with superior hemodynamic control and recovery profiles than fentanyl. Dexmedetomidine had beneficial effects on hemodynamics, surgical field quality, recovery characteristics, and nociceptive properties compared with placebo. Although there was no clear-cut superiority of other adjunct pharmacological modalities on hemodynamic responses during surgery, regional blocks were associated with beneficial impacts on both primary and secondary outcomes. In summary, short-acting anesthetics, analgesics and dexmedetomidine seem to improve intraoperative hemodynamics, blood loss, and recovery qualities during TNTS pituitary surgery. However, definitive conclusions cannot be drawn because of methodological heterogeneity in the identified studies.

Comparison of effects and safety in providing controlled hypotension during surgery between dexmedetomidine and magnesium sulphate: A meta-analysis of randomized controlled trials

Background

Effectiveness of controlled hypotension has been proven in alleviating intraoperative bleeding. Many recent studies emphasized the efficacy of dexmedetomidine and magnesium in providing controlled hypotension during various surgeries. The present meta-analysis of randomized controlled trials (RCTs) was performed to evaluate comprehensively the effects and safety of these two medications.

Methods

Literature search was performed in four databases from inception to April 2019. All RCTs that used dexmedetomidine and magnesium as hypotensive agents were enrolled. The outcomes contained bleeding condition of surgical site, hemodynamic parameters, duration of surgeries, number of patients requiring opioid/analgesia administration, recovery period, and adverse events emerged during surgeries.

Results

Ten studies with 663 patients met with our inclusion criteria. The results indicated that both bleeding score and values of mean arterial pressure (MAP) and heart rate (HR) were significantly lower in patients receiving dexmedetomidine (SMD 1.65 with 95% CI [0.90,2.41], P<0.00001) compared to the patients receiving magnesium. The effect in decreasing the necessity of using opioid/analgesia was affirmative in dexmedetomidine group (29.13% with magnesium vs 10.78% with dexmedetomidine), and the condition was more favorable in magnesium group in reducing recovery period (SMD -1.98 with 95% CI [-4.27,0.30], P = 0.09). Compared with magnesium, using of dexmedetomidine was associated with higher incidence of bradycardia but lower incidence of nausea and vomiting.

Conclusion

Compared with magnesium, dexmedetomidine is more effective to provide promising surgical field condition, favorable controlled hypotension, and less necessity of opioid or analgesia administration. But long recovery period and high-probability bradycardia should be deliberated.

Controlled hypotension for FESS: A randomised double-blinded comparison of magnesium sulphate and dexmedetomidine

Background and Aims:

Intense bleeding during general anaesthesia (GA) is the major limitation during functional endoscopic sinus surgery (FESS). This study was aimed to compare the efficacy of dexmedetomidine and magnesium sulphate (MgSO₄) for controlled hypotension in FESS.

Methods:

Sixty eight patients undergoing FESS were randomised to receive either dexmedetomidine 1 μg/kg over 10 min followed by infusion at 0.2 to 0.7 μg/kg/h (Group D) or MgSO₄ 40 mg/kg over 10 min followed by an infusion at 10 to 15 mg/kg/h (Group M). Anaesthesia and infusion rates for study drugs were maintained with sevoflurane to keep MAP between 60–70 mmHg throughout the surgery. The time to reach the target MAP, the number of patients requiring a minimum and maximum infusion doses of study drugs were noted.

Results:

The mean time to achieve target mean arterial pressure (MAP) was less in group D (10.59 ± 2.04) as compared with (21.32 ± 4.65 min) group M (P < 0.001). The target MAP was achieved between 5–15 min in 73.52% patients (Group D) with an infusion dose of 0.2–0.4 μg/kg/h of dexmedetomidine without the use of sevoflurane, while 82.35% patients in group M required 4% sevoflurane along with >12–15 mg/kg/hr infusion of MgSO₄ to achieve target MAP in 10–20 min.

Conclusion:

Dexmedetomidine is superior to MgSO₄ in achieving target MAP in lesser time with minimum infusion dose.

Intraoperative Dexmedetomidine Maintains Hemodynamic Stability and Hastens Postoperative Recovery in Patients Undergoing Transsphenoidal Pituitary Surgery

Background Transsphenoidal resection of pituitary tumors is the neurosurgical procedure of choice to excise most of the tumors of the sellar/suprasellar region. The main goals of anesthesia are maintenance of hemodynamic stability, provision of conditions that facilitate good surgical exposure, and a prompt and smooth emergence to allow neurological and visual assessment. Dexmedetomidine (Dex), a selective α-2 agonist, is known to maintain cardiovascular stability and anxiolysis and provide pain relief. Therefore, we hypothesized that intraoperative Dex will attenuate hemodynamic response to nasal speculum (NS) insertion, decrease analgesic requirement, and hasten postoperative recovery.

Materials and Methods This prospective, randomized, double-blind, placebo-controlled study was conducted in 60 adult patients of either sex, American Society of Anesthesiologists status I or II undergoing elective pituitary surgery for excision of pituitary adenoma. Randomization was done into two groups; Group D ( n = 30) received Dex bolus 1 μg/kg over 10 minutes, followed by 0.5 μg/kg/h, and group control Group C ( n = 30) received normal saline (0.9%) in a similar manner. A standard anesthesia technique comprising fentanyl, propofol, rocuronium, sevoflurane, nitrous oxide, and oxygen was used. Intraoperative monitoring was uniform and standardized in all the patients; cardiovascular perturbations, if any, were noted and managed appropriately. After completion of surgery, tracheal extubation was performed, and emergence time, extubation time, modified Aldrete score, sedation, pain, time for first analgesic, nausea, vomiting, and shivering were recorded.

Results In both the groups, an increase in heart rate and blood pressure occurred at the time of laryngoscopy and intubation, NS insertion, and extubation, but it was more in Group C ( p < 0.05). In Group D, intraoperative requirement of analgesic, neuromuscular relaxant, and inhalational anesthetic was lesser compared with Group C. Emergence time as well as visual analog scale at emergence was less in Group D.

Conclusions Intraoperative Dex infusion is a reasonable choice in patients undergoing transsphenoidal pituitary surgery.

Total intravenous versus inhaled anesthesia in transsphenoidal tumor surgery

PURPOSE

Visualization of the surgical field is essential for patient safety during endoscopic transsphenoidal tumor surgery. In this retrospective chart review and data analysis of patients undergoing endoscopic transsphenoidal resection of pituitary tumors under general anesthesia we sought to determine if total intravenous anesthesia with propofol and remifentanil leads to decreased bleeding, surgical duration, time to extubation and/or length of stay in the recovery room compared to inhaled anesthesia with sevoflurane or desflurane.

METHODS

After IRB approval, chart reviews of 193 American Society of Anesthesiologists class 1 to 3 patients were conducted who had undergone transsphenoidal, endonasal resections of pituitary tumors under total intravenous or inhaled anesthesia at an academic teaching hospital in the United States over a seven-year time period. One hundred four patients fulfilled the inclusion criteria and were further reviewed. Primary outcome was intraoperative blood loss; secondary outcomes were surgical duration, time to extubation and length of stay in the recovery room.

RESULTS

Gender, age, and Lund-Mackay-Scores were equally distributed between the two anesthetic groups. We found no significant effect of the anesthetic technique, age, gender, or Lund Mackay score on any of the primary or secondary outcomes. The only significant predictor for recovery room length of stay was intraoperative blood loss.

CONCLUSION

Our study shows no evidence that total intravenous anesthesia is superior to inhaled anesthesia or vice versa during endoscopic transsphenoidal sinus surgery with regard to relevant clinical outcome parameters.