Surgical Field Quality in Trans-Nasal Endoscopic Surgeries Using Lignocaine Infusion and Dexmedetomidine Infusion. A Prospective Randomized Control Study

Abstract

Trans-nasal endoscopic surgery (TNES) is a helpful diagnostic and therapeutic modality in otorhinolaryngology surgeries and requires controlled hypotension for better visualization of the surgical field. Recent literature shows evidence of intravenous Lignocaine infusion to produce the controlled hypotension. The study aims to assess and compare the effects of Lignocaine (LIG) and Dexmedetomidine (DEX) infusion with respect to surgical field quality. 101 Consenting adult patients undergoing elective TNES were double-blinded, randomly allocated in one of the two groups and received either DEX infusion of 0.5ug/kg/hr (n = 51) or LIG infusion of 1.5 mg/kg/h (n = 50) after a loading dose. Surgical field score (SVF) as the primary outcome and secondary outcomes such as variations in hemodynamic parameters, the requirement for rescue agents and total blood loss were recorded. Both the groups were comparable with respect to patient demographics, total duration of anesthesia and surgery. SVF scores were significantly better in the LIG group during the first 105 min of the surgery (p < 0.05). In response to intubation, hemodynamic parameters were lower in LIG group. The requirement of other adjuvant drugs, total blood loss (166.40 ml vs. 251.17 ml) and extubation time were also significantly lower in the LIG group. The study concludes that intravenous Lignocaine gives a better surgical field in the first 105 min of surgery, comparable hemodynamics and decreased blood loss in patients undergoing TNES as compared to Dexmedetomidine infusion. Hence its role as an agent for controlled hypotension during TNES surgery is promising.

Introduction

The primary objective of anesthesia is balancing the patient's hemodynamics with the best possible surgical outcome. In modern anesthesia, a multimodal approach to balanced anesthesia is targeted with combined general anesthetics and systemic drugs.

Trans-nasal endoscopic surgery (TNES) is a helpful diagnostic and therapeutic modality in paranasal sinus diseases [1] TNES are associated with significant intraoperative bleeding, pain, epistaxis, and transient headaches [2]. Intra-operative surgical site bleeding is one major complication and all anesthetic techniques pursue the objective to reduce it to achieve better precision, reduced operative time, and faster postoperative wound healing [1]. Topical medications, surgical positioning, nasal packing, inhalational anesthetics, and systemic drugs are some of the documented methods [3].

Controlled hypotension is one of the methods to control bleeding [4]. It reduces blood loss, enhances the operative field quality (dryness) and studies on hypotensive anesthesia have shown a statistically significant reduction in blood loss [5]. Several systemic drugs have been used to achieve controlled hypotension. However, they have their own set of limitations. Recent studies have advocated the use of drugs like Lignocaine and Dexmedetomidine to achieve controlled hypotension [6, 7].

Lignocaine, known for blunting intubation response, has recent evidence to produce controlled hypotension [6]. Dexmedetomidine (DEX), has documented hypotensive action too. However, there are limited human studies in the current literature investigating the role of Lignocaine and Dexmedetomidine infusion in TNES concerning the surgical visual field (SVF).

The study aims to assess and compare the effects of intravenous Lignocaine infusion to that of Dexmedetomidine infusion in TNES.

Materials and Methods

This study was a single institution, double-blinded, prospective randomized controlled trial. The study was approved by the Institutional Ethics Committee with IRB no. INT/IEC/2017/1303 and signed written informed consent was obtained from all participants. The study was registered in Clinical trial registry of India (http://www.ctri.nic.in) before enrolment of the first patient with Reg no. CTRI/2017/11/010,557.

Inclusion Criteria

• Age group: 18–60 years.

• American Society of Anesthesiology (ASA) Status: ASA I and II.

• Undergoing elective TNES of upto 2 h in duration.

Exclusion Criteria

• Known cerebrovascular disease or insufficiency

• Known coagulation defects

• Known drug hypersensitivity

• History of hepatic or renal insufficiency

• Body Mass Index (BMI) > 35

• Poorly controlled hypertension

• Use of B- Blockers

• History of Bradycardia episodes /Atrio-ventricular block / Conduction defects.

Outcomes Meassured

Primary Outcome

To assess if intravenous Lignocaine infusion provides a better surgical field in patients undergoing TENS as compared to Dexmedetomidine infusion.

Secondary Outcomes

• Variations in hemodynamic parameters such as Heart rate (HR) and Blood pressure (Systolic, Diastolic, Mean)

• The requirement of other adjuvant agents (total number of patients requiring and mean consumption in each group) for controlled hypotension.

• The total fluid used, blood loss, extubation time, post-operative pain score (Numerical rating scale; NRS), Ramsay sedation score and perioperative complications.

Randomisation and Allocation

For all patients; demographic data, baseline vital parameters, and investigations were recorded. A computer-generated randomization list was used to assign patients into Dexmedetomidine (group A) and Lignocaine (group B). Sealed envelopes mentioning the rate of infusion were given. Study solutions were prepared, and data was collected by two different anesthesiologists and hence blinding was ensured.

Study Protocol

On arrival to the operating room and after standard monitors were attached; baseline parameters like Heart Rate (HR), Mean Blood Pressure (MBP), Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), and Oxygen Saturation were recorded. Intra-operative fluid and analgesics were the same for all patients.

In Group A, a loading dose of 1 ug/kg DEX over 10 min before the start of the surgery, followed by an infusion of 0.5 µg/kg/h until the end of surgical closure was given.

In Group B, 1% Lignocaine was given at a rate of 1.5 mg/kg/h (0.15 ml/kg/h) following a bolus dose of 1.5 mg/kg over 10 min before the start of the surgery, till the end of surgical closure.

Pre-oxygenation was followed by Inj Fentanyl 2 µg/kg following which induction with Inj. Propofol at 1–2 mg/kg and Inj Vecuronium 0.1 mg/kg for achieving muscle relaxation and smooth intubation was given. The patient was mechanically ventilated targeting normocapnia (end-tidal CO2 35–40 mmHg).

Anesthesia was maintained with Nitrous oxide (N20) and Oxygen flow at 50:50 and Sevoflurane for achieving a Minimum Alveolar concentration (MAC) of 1. Target values for achieving controlled hypotension were a 30% reduction in MAP from the baseline. In all patients, the surgeon injected or instilled adrenaline in a concentration of 1:1,00,000 in a volume of 10-15 ml locally pre-incision.

Data Collection

Data was collected as:

Assessment of intra-operative bleed (By the surgical field assessment score) at 15 min interval from the time after start of surgery, by the Fromme et al. [5] score.

Score 0 No bleeding in the nasopharynx or a vessel.

Score 1 Slight bleeding, no suctioning of blood required.

Score 2 Bleeding requiring occasional suctioning. The surgical field not threatened. Score 3 Bleeding requiring frequent suctioning. Bleeding threatens surgical field a few seconds after suction is removed.

Score 4 Moderate bleeding, frequent suctioning required. Bleeding threatens surgical field directly after suction is removed.

Score 5 Severe bleeding, constant suctioning required, the surgical field is severely threatened. The bleeding appears faster than can be removed by suction. Surgery usually not possible.

Values for secondary outcome were recorded starting from baseline values at the following time points-intubation, adrenaline instillation and at 15 min interval after the start of surgery. Duration of surgery of approximately 2 h were included in the study.

SBP, DBP, MBP, and HR were recorded at:

• Baseline

• After intubation

• 2 min after instillation/injection of adrenaline

• At 15 min frm the start of surgery.

If the target BP was not achieved: MAC was titrated from 1 to maximum 1.5 followed by Inj fentanyl 1 µg/kg if the last dose was 30 min prior. If despite the above measures, target BP was not achieved; adjuvants like Nitroglycerine (NTG), Esmolol or Propofol were added as per the attending anesthesiologist's discretion.

If BP values were less than the target value: MAC was reduced to 0.8. followed by two doses of Mephentermine/Phenylephrine in a gap of 5 min to achieve the target levels.

In the further absence to achieve the set targets, the study sample was considered a failed sample, the drug infusion was continued after titrating it to a lower rate to target a MABP reduced to 30% from the baseline and included as a part of the intention to treat analysis. At any time during the study, bleeding score more than 3 were rescued with adjuvant drugs.

In the postoperative period a note of the following was made:

• Side effects: (Nausea, Hypotension {Mean BP < 60 mmHg}, Bradycardia {HR < 50}, Tachycardia {HR > 110} and Vomiting)

• Sedation—RAMSAY SCORE

• Pain Numeric Rating Scale (NRS)

• Opioid requirement.

• Adverse event (Cardiac Arrhythmias, Any sign of toxicity, Death)

Statiscal Analysis

Assuming a difference of 1 grade in surgical field quality between the two groups as clinically significant; a sample size of 28 in each group was calculated taking the alpha error as 0.05 and beta error as 0.1. Considering attrition/drop out of samples during the study, a minimum sample size of 30 in each group was decided. Since we could enroll more patients in the duration of study, the final study was conducted on a total of 101 eligible pateints after randomisation; with 50 and 51 in both the groups respectively.

Data was described in terms of mean, median, frequencies, and percentages. Variable distribution was tested with the Kolmogorov Smirnov tests of Normality. Student t-test and Mann–Whitney were applied for normally distributed and skewed data. Group comparisons were made using the Chi-Square test or Fisher's exact test. For time-related variables of skewed data Wilcoxon Signed-rank test; for Normally distributed data ANOVA followed by Dunnet t-test was carried out. A p-value < 0.05 was considered significant. The analysis was conducted using SPSS (Stastical Package for Social Sciences) STATISTICS version 22.0.

Results

Of the 129 patients enrolled in the study, 51 and 50 patients in group A and group B respectively were analyzed after randomization. Figure 1 shows the consort diagram of the study.

Fig. 1.

Consort diagram for the study depicting recruitment, randomisation, allocation and analysis

The demographic data, baseline investigations and the total duration of anesthesia and surgery in both the groups were comparable (Table 1).

Table 1.

-Comparison of the demographic data between the two groups

	A	B	p-Value
Age (Years)a	36.86 ± 11.35	39.34 ± 10.23	0.253
Weight (kg)a	64.31 ± 12.08	65.28 ± 8.74	0.647
Gender (M/F)b	33/18	35/15	0.571
ASA (I/II)b	42/9	40/10	0.762
Anaesthesia (duration in min)	90.784 + 19.14	87 + 22.7	0.182
Surgery (duration in min)	70.98 + 16.64	68.04 + 21.127	0.219

^aCompared using independent sample student’s t-test

^bCcompared using Pearson’s Chi’Square test. p value < 0.05 was considered as statistically significant

Primary Outcome: Surgical Visual Field

The primary outcome was to assess the surgical visual field (SVF) scores. The mean SVF scores were significantly lower in group B as compared to group A after the attainment of target blood pressure i.e. from 15 min post start of surgery till 105th min. (SVF105). However, no statistical difference was observed after that in the two groups (Table 2).

Table 2.

Primary Outcome: Surgical visual field between the two groups expressed as the mean and standard deviation

SVF Scoring	A Mean ± STD. Deviation	B Mean ± STD. Deviation	p-Value
SVF15	1.765 ± 0.6508	1.280 ± 0.7570	0.001*
SVF30	1.902 ± 0.6710	1.400 ± 0.6061	< 0.001*
SVF45	1.706 ± 0.6417	1.360 ± 0.5980	0.006*
SVF60	1.681 ± 0.6292	1.238 ± 0.5323	0.001*
SVF75	1.381 ± 0.5896	1.113 ± 0.4787	0.014*
SVF90	1.500 ± 0.5477	1.229 ± 0.5345	0.013*
SVF105	1.50 ± 0.577	1.23 ± .577	0.021*
SVF120	1.50 ± 0.707	1.50 ± .707	1.00

*Statistically significant; compared using independent sample student’s t-test p value < 0.05 was considered significant with a confidence interval of 95%

Secondary Outcomes: Hemodynamic Variability

The variations in HR were found to be comparable at all time intervals except during intubation ( Group A vs. Group B; 93.608 + 15.041 vs. 85.260 + 18.56 beats/min), which was statistically significant (p-value 0.015).

Systolic blood pressure (SBP): Variations in mean SBP were significantly lower in Group B as compared to Group A during intubation, adrenaline instillation and at the 105th-min time point.

Diastolic blood pressure (DBP): DBP was significantly lesser in group B as compared to group A at intubation and adrenaline instillation and at the 105th-min time point.

Mean blood pressure (MBP): MBP in group B showed significantly lower values during intubation, adrenaline instillation, and 105th-min time point.

Target hypotension (MBP < 30% baseline) was achieved by a maximum of 15 min post the start of surgery, since readings were recorded at 15 min interval that is roughly 25 min since the start of infusion in both the groups.

Minimum alveolar concentration (MAC): MAC was comparable at all time points except at the 45th and 60th min where group B had significantly lower MAC requirements as compared to group A (Table 3).

Table 3.

Shows variations in heart rate,systolic, diastolic, mean blood pressure and MAC between the group A & B at different time points

HR				SBP			DBP			MBP			MAC
	A	B	p-Value	A	B	p-Value	A	B	p-Value	A	B	p-Value	A	B	p-Value
Time points	Mean ± SD	Mean ± SD		Mean ± SD	Mean ± SD		Mean ± SD	Mean ± SD		Mean ± SD	Mean ± SD		Mean ± SD	Mean ± SD
Baseline	84.765  ±  14.6678	83.400 ± 13.279	0.0625	130.353  ±  15.6152	127.980  ±   14.5707	0.432	79.137  ±   10.2294	77.440  ±   9.943	0.4	97.647  ±   11.6272	95.58  ±   11.695	0.377	0.00 ± 0.00	0.00 ± 0.00	0.00
Intubation	93.608  ±  15.0414	85.260  ±  18.569	0.015	132.25  ±   18.46	116.780  ±   17.9436	< 0.001	81.824  ±   13.7065	72.560  ±   14.6276	0.001	97.39  ±   16.653	86.100  ±   14.7583	< 0.001	0.963 ± 0.1969	0.958 ± 0.1885	0.951
ADR Instillation	88.373  ±  19	83.580  ±  14.466	0.158	113.941  ±   18.382	105.000  ±   13.2002	0.006	71.08  ±   13.526	64.940  ±   12.0533	0.018	85.804  ±   15.4997	78.640  ±   10.6364	0.008	1.135 ± 0.1958	1.134 ± 0.1409	0.418
15 min	76.314  ±  15.7804	71.640  ±  11.335	0.091	92.353  ±   13.068	91.300  ±   7.9237	0.627	54.941  ±   11.5281	52.360  ±   5.795	0.161	67.706  ±   12.2332	65.320  ±   5.902	0.28	1.206 ± 0.2509	1.194 ± 0.1671	0.415
30 min	72.490  ±  14.677	67.780  ±   12.588	0.087	91.922  ±   10.8441	90.040  ±   7.8791	0.322	52.118  ±   9.4523	53.200  ±   6.1578	0.498	65.400  ±   8.1335	65.52  ±   4.844	0.94	1.225 ± 0.2667	1.186 ± 0.1885	0.051
45 min	67.980  ±  14.8209	66.060  ±   11.657	0.471	91.216  ±   8.2227	88.300  ±   7.7493	0.065	53.216  ±   8.0108	53.440  ±   7.2567	0.883	65.912  ±   6.6878	64.600  ±   5.4772	0.284	1.233 ± 0.2651	1.160 ± 0.2010	0.012
60 min	69.191  ±  15.8081	65.195  ±   10.955	0.178	89.511  ±   8.5284	91.293  ±   6.7426	0.248	54.128  ±   8.2294	53.098  ±   5.5218	0.466	65.213  ±   7.8101	65.850  ±   5.1776	0.658	1.200 ± 0.2634	1.134 ± 0.1741	0.031
75 min	72.500  ±  16.3088	65.563  ±  11.413	0.153	90.091  ±  10.8668	87.188  ±  7.9935	0.13	54.333  ±  8.6737	52.750  ±  4.5971	0.919	66.536  ±  8.4264	64.22  ±  4.1347	0.082	1.200 ± 0.2370	1.200 ± 0.1549	0.674
90 min	80.75  ±  16.299	73.71  ±  12.189	0.367	90.71  ±  6.499	88.71  ±  7.697	0.161	52.25  ±  6.341	51.43  ±  7.208	0.545	65.10  ±  5.806	63.91  ±  5.711	0.298	1.257 ± 0.1512	1.229 ± 0.1890	0.395
105 min	78.60  ±  13.631	66.67  ±  6.11	0.211	92.40  ±  6.58	80.33  ±  2.517	0.012	55.60  ±  6.229	53.33  ±  3.512	0.027	67.90  ±  5.933	62.30  ±  4.933	< 0.001	1.275 ± 0.1893	1.233 ± 0.0577	0.364
120 min	65.00  ±  4.243	67.00  ±  1.414	0.592	89.50  ±  6.364	87.00  ±  4.243	0.689	60.00  ±  11.314	59.50  ±  7.778	0.964	66.00  ±  5.657	63.00  ±  4.243	0.609	1.150 ± 0.2121	1.200 ± 0.0000	1.00

Our study also analyzed the need for adjuvant drugs to maintain the set target for controlled hypotension as the secondary outcome. Group B had a lower requirement for added doses of fentanyl, propofol, and mephentermine, compared to group A in terms of no. of patients requiring it as well as the total drug consumption (Table 4). However, there was not much statistical difference in the use of adjuvant drugs. The total intra-operative fluid requirement, blood loss, total extubation time, post-operative NRS and Ramsay sedation scores assessed at 30 min and 1 h were significantly lesser in Group B compared to group A (Table 4) Group A also had more incidence of intraoperative and postoperative side-effects (Table 5).

Table 4.

Mean and standard deviation of the average doses of various adjuvant drugs, total fluid used, blood loss,extubation time, post-operative NRS and Ramsay sedation scores between the two groups

Variables	A	B	p Value
Average drug consumption ( no. of patients requiring boluses)
Fentanyl (µg)	62.78 ± 6.667 (25)	58.6 ± 12.035 (9)	0.02*
Esmolol (mg)	23.3 ± 18.61(6)	20 ± 0.00 (2)	0.188
Propofol (mg)	41.67 ± 14.035 (12)	25 ± 7.071 (2)	0.002*
Labetolol (mg)	15 ± 0.0 (1)	0
Metoprolol (mg)	2.5 ± 0.0 (2)	0
Mephentamine (mg)	5.66 ± 5.074 (9)	3.00 (1)	0.030*
Atropine (mg)	0.6 (3)	0	0.083
Total fluid used (ml)	814.706 + 342.533	646 + 248.00	0.003
Blood loss (ml)	251.176 + 83.0337	166.4 + 86.983	< 0.001
Extubation time (min)	10.02 + 1.9747	6.98 + 2.208	< 0.001
NRS
30 min	2.863 + 0.6934	1.88 + 0.6590	< 0.001
1 h	1.294 + 0.6417	0.42 + 0.5741	< 0.001
Ramsay seation score
30 min	2.569 + 0.700	2.060 + 0.3136	< 0.001
1 h	2.078 + 0.2715	2.00 + 0.00	0.044

Groups compared using independent sample student’s t -test

Table 5.

Comparison of the various side-effects reported intra-operatively and postoperatively between the two groups

Side-effects	Number of cases (%)
	A	B
Intra-operative bradycardia/hypotension	4 (7.84%)	0
Post OP bradrcardia/hypotension	3(5%)	0
Nausea	1(1.96%)	0
Vomiting	1(1.96%)	1 (2%)
Post operative headache	0	2 (4%)

Groups compared using Pearson’s Chi- square test

Discussion

In our study we have compared the effect of Lignocaine infusion with that of Dexmeditomidine infusion in providing better surgical visual field (SVF) scores.Evolution in anesthetic techniques and drugs along with optimization of surgical and patient factors leads to better patient satisfaction and care. TNES are routine daycare surgeries and hence achieving good peri-operative hemodynamic stability, lesser complications and good post- operative analgesia are of prime importance. Intra-operative bleeding along with with poor postoperative analgesia and sedation delay the recovery of the patient [8]. Of the various anesthetic techniques mentioned, controlled hypotension to mitigate intra-operative bleeding has been found to be beneficial [4, 6]. In our study we have compared the SVF to compare the intra-operative bleeding between the two agents. Lignocaine is a amide local anesthetic which has stood the test of time in its role of blunting intubation response and has shown promising results in controlled hypotension. In recent studies Dexmedetomidine; a highly selective alpha 2 agonist has been documented to have a hypotensive action secondary to its sympatholytic, sedative and added vasoconstrictive effects [6, 7].

In our study, the median SVF scores were better in the Lignocaine group as compared to Dexmedetomidine group (p-value < 0.005) at all time points during the first 105 min of the surgery after the target MBP was achived with median bleeding scores not more than 2. However, no difference was found thereafter.

Omar et al. also demonstrated the ability of Lignocaine infusion to cause controlled hypotension in patients undergoing TNES thus concluding that it led to better surgical field quality [6]. Guven et al. had similarly concluded that Dexmedetomidine improves surgical field quality [7].

Several possible mechanisms can be explained for the controlled hypotension and better SVF as evidenced by our study. Enlund et al. had first hypothesized and concluded that Lignocaine infiltration leads to a dose-dependent decrease in heart rate and blood pressure [9]. Chamberlain et al. had established that local anesthetics exert a negative inotropic action on the heart mediated by calcium influx which is dose-dependent [10]. Yukioka et al. had established the ability of Lignocaine infusion to blunt the airway's reflexes [11]. Thus, Lignocaine prevents the initial rise of blood pressure and tachycardia that once triggered leads to severe bleeding during the initial stages of dissection. Sung et al. concluded that Lignocaine produces vasoconstriction in vivo and in-vitro [12]. Another study by Jorfedtet al postulated that at plasma concentrations of 3–6 mcg/kg; vasoconstriction takes place in parts of the peripheral circulation [13]. In our study, the combined effects of hypotension and vasoconstriction possibly explain the better SVF and lower blood loss in the Lignocaine group.

Our study also demonstrated that Lignocaine blunts the hemodynamic response. The comparison of the hemodynamic variables including SBP, DBP, MBP, and HR at time points during intubation and adrenaline instillation demonstrated the sympatholytic action of Lignocaine which were statistically significant when compared to Dexmedetomidine. However, both the drugs helped to achieve the target of controlled hypotension by maximum 15–30 min post intubation, and these findings are in accordance with studies done by Omar et al. and Guven et al. [6, 7].

The need for adjuvant drugs for maintaining the target level of MBP was compared. The required doses of Fentanyl were higher in the Dexmedetomidine group with more patients (25 vs. 9) requiring rescue doses as compared to the Lignocaine group; the difference being statistically significant (p = 0.02). The bolus doses of Propofol (n = 12 vs. 2) and other B-Blockers were also higher in the Dexmedetomidine group. These findings strengthen the evidence of Lignocaine as an agent for achieving controlled hypotension with lower needs for added adjuvants. Compared to placebo, Lignocaine had demonstrated significant opioid-sparing effects [6]. Das et al. had concluded that Dexmedetomidine bolus doses lead to a lower requirement of fentanyl and other agents like Nitroglycerine [8]. These studies potentiate the opioid-sparing effect of both the drugs, however in our study; Lignocaine proved to have a better opioid-sparing action.

In our study, Dexmedetomidine group received higher bolus doses of Mephentermine (9 vs. 1). This is supported by a study comparing Dexmedetomidine to placebo [7]. In a similar study comparing Dexmedetomidine and Clonidine in FESS surgeries, Dexmedetomidine led to longer duration of hypotension [8].

When extubation time and postoperative sedation scores were compared after discontinuation of the drug infusions at the start of surgical closure in both the groups, Dexmedetomidine group had higher scores as compared to Lignocaine group and the difference was statistically significant. A study by Rani et al. on the attenuation of the airway and circulatory reflexes during emergence and extubation showed a greater degree of sedation with Dexmedetomidine [14].

However, Sharma et al. observed that emergence and extubation time was comparable in both the groups [15]. Both the studies used a single bolus dose (over 5 min and 60 s respectively) of the drug before extubation and it is plausible that infusion doses as used in this study throughout the surgery would lead to higher sedation scores.

On comparing the NRS pain scores, lower and statistically significant score was found in the Lignocaine group at 30 min and 1 h postoperatively. Koppert et al. suggested that Lignocaine has modest demonstrable analgesic properties [16]. During surgery, the benefit of a continuous small-dose Lignocaine infusion was also confirmed by Groudine et al. [17]. A study by Guven et al. on systemically used dexmedetomidine, observed that it provides modest postoperative analgesia and reduces opioid requirement [7]. This effect has been attributed to its confounding sedative effects.

The risk of Lignocaine toxicity with infusion doses was addressed with the fact that the dilution and dosages in the current study were much lower and had a lower propensity to cause untoward central nervous system symptoms. A continuous infusion of Lignocaine in a dose of 1.5–2.0 mg/kg have a variable plasma levels between 1.3 and 4.0 µg/mL and had no side effects [16].

The use of Sevoflurane had a possible favorable impact on the surgical site bleeding. Isoflurane being a strong dose-dependent vasodilator leads to increased blood flow velocity and perfusion of the nasal mucous membrane contributing to increased surgical bleed [18].

One of the limitation of the study was the absence of the control group; however there are existing studies [6, 7] to demonstrate the effect of the two drugs with respect to placebo and secondly, in our operative setup it is a part of anesthetic regime to provide hypotensive anaesthesia for TNES, the drug choice based on the anesthesiologist’s discretion.

Our study concludes that intravenous Lignocaine gives better SVF scores as compared to Dexmedetomidine during the first 105 min of the surgery (p < 0.05). Intubation response in HR, SBP and DBP were lower in the Lignocaine group with a p-value of 0.015, 0.002 and 0.001 respectively. The mean requirement of other adjuvant drugs, total blood loss (166.40 ml vs. 251.17 ml) and extubation time were also significantly lower in the Lignocaine group. Hence its role as an agent for controlled hypotension is promising.

Source of Funding

The Author(s) declares no financial support for the research, authorship, and/or publication of this article.

Compliance with Ehical Standards

Conflict of interest

No potential conflict of interest relevant to this article was reported.

Availability of Data

Available on request

Code Availabilty

: Not applicable.

Consent to Participate and Publish

Informed written consent was obtained from all individual participants included in the study.

Ethical Approval

The study is registered in ctri.nic.in—CTRI/2017/11/010,557 (Dated: 20/11/2017) and approved by Institutional Ethics Committee (IRB NO): INT/IEC/2017/1303.