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.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Functional endoscopic sinus surgery (FESS) is an advanced surgical procedure performed in otorhinolaryngological diseases with an aim to restore the drainage and aeration of paranasal sinuses. Having a clear visual field is a critical part of this surgery. Overall, reduced visibility of the surgical field (due to bleeding) is related to an increased risk of dangerous vascular; orbital and intracranial complications; prolonged duration of surgery, and reduced quality of intervention.[1] Various methods have been used to decrease bleeding intraoperatively. Controlled hypotension using total intravenous anesthesia (TIVA) (using propofol and other Intravenous [IV] agents) is a new technique being preferred in FESS.

SUBJECTS AND METHODS

The study was conducted after obtaining the Institutional Ethics Committee approval. Patients in the age group of 16–60 years with physical status of the American Society of Anesthesiologists (ASA) Classes I and II, undergoing FESS under general anesthesia were included in the randomized controlled study. A total of sixty patients undergoing FESS were randomly divided into two groups of thirty each after taking informed consent and approval from the Hospital Ethics Committee. The patients were randomly divided into Group I and Group II. Group I consisted of thirty patients who received isoflurane-based inhalational anesthesia. Group II consisted of another thirty patients who were administered TIVA with propofol. Inclusion criteria were: (1) adults with 16–60 years of age, (2) ASA physical Status I and II, (3) either sex, (4) FESS surgery up to 3 h. Exclusion criteria were patients with: (1) bleeding disorders, (2) major hepatic, renal, or cardiovascular dysfunction, (3) pregnancy, (4) patients on anticoagulation therapy, (5) postural hypotension, (6) anticipated airway difficulty, (7) uncontrolled hypertension and myocardial infarction.

All patients were visited a day before the surgery and explained in detail the anesthetic procedure, and informed and written consent was obtained. All patients were kept nil orally from 12 midnight before the day of surgery. They received tablet alprazolam 0.5 mg as premedication a day before the surgery.

On arrival in the operating room, standard monitors were attached. IV line was started using appropriate sized cannula. Parameters such as pulse rate, blood pressure (BP), respiratory rate, and oxygen saturation (SpO2) were recorded after 5 min of stabilization and taken as a baseline reading. Preoxygenation with 100% oxygen for 3 min was done. Induction of anesthesia was done with midazolam (2 mg), fentanyl (2 μg./kg), and propofol (2 mg/kg). After ensuring adequate ventilation, injection succinylcholine (2 mg/kg) was administered to facilitate orotracheal intubation, and oropharyngeal packing was done. Immediately after intubation, vital parameters were recorded.

After intubation, maintenance of anesthesia was done with oxygen in air and isoflurane up to two minimum alveolar concentration in Group I. In Group II, maintenance was done with oxygen in air and propofol infusion at 12 mg/kg/h for 10 min, then 10 mg/kg/h for next 10 min and continued at 8 mg/kg/h. The target in both groups was to achieve a mean arterial BP of 60–70 mmHg. If the target BP was not achieved, then injection esmolol in a dose of 1 mg/kg bolus was given as a rescue drug and then repeat doses were given as and when required. The total dose of propofol given was noted. Neuromuscular blockade was provided with injection vecuronium.

All the vitals were observed every 1 min for 5 min, then every 5 min for 15 min, and then every 15 min till the end of the surgery. Surgeon's opinion was also recorded regarding the quality of surgical field.

The quality of surgical field was evaluated every 15 min using the surgical field rating (SFR) scale of six points proposed by Fromme et al.:[2] 5 - massive uncontrollable bleeding, 4 - heavy but controllable bleeding that significantly interfered with dissection, 3 - moderate bleeding that moderately compromised surgical dissection, 2 - moderate bleeding – a nuisance but without interference with accurate dissection, 1 - bleeding, so mild it was not even a surgical nuisance, 0 - no bleeding and virtually bloodless field. Surgical field was graded as good, fair, and poor as: good - SFR scale 0 or 1, fair - SFR scale 2 or 3, poor - SFR scale 4 or 5.

Intraoperative bleeding was measured by collecting blood in a marked container of 25 ml capacity with the precision of 0.5 ml. The blood soaked by gauge pieces and nasal packs was measured by weighing the gauge pieces before and after the procedures.

During intraoperative period, the occurrence of side effects such as hypotension and bradycardia, and during postoperative period, side effects such as rebound hypertension, vision problems, altered sensorium, chest pain, jaundice, malaise, and fever were noted. The data were analyzed, compared, and evaluated statistically based on the quality of surgical field, surgeon satisfaction score, and incidence of intraoperative complications. Effect size was calculated, and taking alpha error 0.05, power of study achieved was 98%. Chi-square test for nonparametric data and Student's t-test for parametric data were applied. 95% confidence interval for means was also calculated. P < 0.05 was considered statistically significant and <0.001 as highly significant.

RESULTS

Demographic data including patient age, sex, height, weight, and ASA grade distribution were comparable in the two groups [Table 1] with P > 0.05.

Table 1

Demographic data

Hemodynamics (heart rate, systolic BP, diastolic BP, mean arterial pressure, SpO2 at various time intervals, time to reach target BP) in both groups were comparable statistically (P > 0.05). When compared to the baseline, there was no significant difference between the two groups with regard to the heart rate at different time intervals [Figure 1].

Figure 1

Comparison of heart rate at various time intervals in each group.

Use of rescue drug esmolol to reach the target BP in the two groups was statistically nonsignificant (P > 0.05) [Figure 2].

Figure 2

Comparison of usage of rescue drug (esmolol) to reach target blood pressure in each group.

The total blood loss (TBL) during surgery in the Group II was statistically much less than the Group I (P < 0.001) [Table 2].

Table 2

Comparison of total blood loss during surgery in each group

The quality of surgical field in Group II was statistically better as compared to Group I. Although the grade of quality of surgery was statistically insignificant at the start of surgery, it became highly significant toward the end of surgery, as more patients in Group II showed good quality of surgical field toward the end of surgery as compared to Group I [Table 3].

Table 3

Comparison of quality of surgical field in each group

The incidence of intraoperative complications was much more in the Group I as compared to Group II (P < 0.05) [Figure 3].

Figure 3

Comparison of incidence of intraoperative complications in each group.

DISCUSSION

FESS being a delicate technique needs a clean and blood-free field. In nasal surgeries, local anesthesia used traditionally causes discomfort and pain as the patient remains conscious, in addition to the risk of having an incomplete block. Hence, general anesthesia is often preferred over topical anesthesia in FESS as it produces immobile surgical field, effective airway protection, adequate analgesia, patient comfort, and the provision for controlled hypotension if required.[3] The use of hypotensive anesthesia further reduces bleeding and thus clearing field during surgery.[4]

The hypotensive state during general anesthesia is achieved by reducing peripheral vascular resistance, decreasing cardiac output, or using a combination of both. Cardiac output is affected by changing the blood inflow into the heart and heart rate. Peripheral vascular resistance is decreased by peripheral vasodilatation, which is caused by terminating sympathetic stimulation by several agents such as α-2A adrenergic agonists (clonidine and dexmedetomidine), vasodilators (nitroprusside, nicardipine and nitroglycerin), beta-adrenergic antagonists (propranolol and esmolol),[5] and high doses of inhaled anesthetics (isoflurane and sevoflurane). Controlled hypotension using TIVA (using propofol and other IV agents) is relatively a new concept widely gaining popularity.[67]

Isoflurane is a popular agent for inducing hypotension because of its simplicity to use and has favorable effects on systemic and cerebral circulation. It produces a dose-dependent reduction in systemic vascular resistance and BP by acting directly on the smooth muscles of blood vessels. Cardiac output is well maintained. Isoflurane may increase the velocity of blood flow in the muscles two or even three times,[8] thus increasing perfusion of the nasal mucous membrane and surgical bleeding as well. Studies show that desflurane, sevoflurane, or isoflurane provides adequate induced hypotension and similar operating conditions and any of them can be used safely and equally in these surgeries.[9] However, sevoflurane and desflurane are more costlier than isoflurane. Halothane, though a medium potency vasodilator, is arrhythmogenic and adrenaline cannot be used along with it. Hence, isoflurane was preferred in this study.

Higher doses of isoflurane normally lead to tachycardia, thus less chances of getting controlled hypotension; however, in this study, this did not happen due to the use of esmolol.

Propofol can be administered to reduce the BP intraoperatively. The major cardiovascular effect of propofol is a decrease in arterial BP owing to a drop in systemic vascular resistance, cardiac contractility, and preload.[10] It causes direct myocardial depression and peripheral vasodilatation. It blunts the sympathetic response to endotracheal tube insertion and surgical stimulation. Infusion rate based on patients’ body weight and hemodynamic response provide adequate BP control. It also decreases cerebral metabolism, and cerebral blood flow is reduced by autoregulation. This reduces flow through the ethmoidal, sphenoidal, and frontal sinuses improving surgical visibility.[4] Some studies[1112] found no statistically significant difference with propofol over inhalational agents, while others[1314] consider propofol better than inhalational agents. In this study, a higher dose of propofol was used as compared to previous studies to know if this dose produced better results.

In endoscopic sinus surgery, there is a stimulation of the branches of the trigeminal nerve which in turn stimulates the sympathetic nerve centers in the medulla resulting in tachycardia and increase in BP. Beta-adrenergic antagonists attenuate this response. Esmolol is a cardioselective beta blocker. It has a quick onset and short duration of action.[15] Being metabolized by esterases, it can be safely administered in patients with hepatitis or renal impairment.[16] Guney et al.[17] found that esmolol provides hemodynamic stability and good surgical field visibility.

In this study, the TBL with TIVA (with propofol) was significantly reduced as compared to inhalational anesthesia (isoflurane) may be due to reduced cardiac output or anemization of area to be operated. Due to the reduced blood loss, there was improved quality of surgical field also.

The incidence of intraoperative complications was much more in the inhalational anesthesia (isoflurane) group as compared to TIVA (propofol) group, probably due to more intraoperative blood loss and worse quality of surgical field in the inhalational anesthetic group as compared to TIVA with propofol group. Similarly, a study by Naik and Naik[14] showed less intraoperative complications in TIVA as compared to inhalational anesthesia. However, in terms of postoperative pain, nausea and vomiting, no statistically significant difference is seen between TIVA and inhalational anesthesia.[18]

CONCLUSION

This study concludes that in FESS, using TIVA with propofol decreases blood loss and the incidence of complications during surgery and also provides good quality of surgical field as compared to isoflurane.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.