Functional endoscopic sinus surgery (FESS) is a widely performed surgical procedure for the management of chronic rhinosinusitis, nasal polyposis, and selected disorders of the paranasal sinuses. The technique enables direct visualization and treatment of diseased sinonasal structures while preserving normal anatomical function wherever possible. Advances in endoscopic instrumentation, imaging, and surgical techniques have improved its effectiveness and clinical applicability. Nevertheless, maintaining an adequately visible operative field remains an important challenge because of the extensive vascularity of the nasal and paranasal sinus mucosa.

Intraoperative bleeding can interfere with endoscopic visibility, prolong surgical duration, and increase the difficulty of identifying critical anatomical landmarks. Poor visualization may be particularly concerning near the skull base, orbit, and major vascular structures. Anaesthetic management is therefore an essential component of safe endoscopic sinus surgery. Effective collaboration between the anaesthesiologist and otorhinolaryngologist is required to balance favorable surgical conditions with preservation of adequate systemic perfusion.

Hemodynamic responses during FESS are influenced by multiple factors, including induction agents, airway instrumentation, anaesthetic depth, surgical stimulation, topical and infiltrated vasoconstrictors, and medications used for intraoperative blood pressure management. Heart rate and mean arterial pressure are commonly monitored indicators of cardiovascular responses. However, the relationship between systemic arterial pressure and local surgical bleeding is complex because it is also influenced by cardiac output, venous pressure, vascular tone, and mucosal perfusion.

Controlled hypotension has historically been used to improve surgical visibility during FESS. This technique involves deliberate reduction of arterial pressure under controlled anaesthetic conditions. Srivastava et al. compared esmolol and nitroglycerine for controlled hypotension in patients undergoing FESS and evaluated surgical field conditions using standardized bleeding scores [1]. The investigators highlighted the relevance of choosing appropriate hemodynamic strategies to improve operative visibility.

Shams et al. compared dexmedetomidine and esmolol in a randomized study involving 40 patients undergoing FESS [2]. Both medications were used to facilitate controlled hypotension, and the investigators evaluated mean arterial pressure, heart rate, blood loss, recovery characteristics, and surgical field quality. Their work demonstrated the importance of assessing cardiovascular parameters alongside surgical conditions when selecting perioperative anaesthetic strategies.

The effects of anaesthetic technique on bleeding and cardiovascular responses have also been investigated. Miłoński et al. compared three general anaesthetic regimens and reported differences in mean intraoperative blood loss between groups [3]. Their findings suggested that anaesthetic technique may influence the operative environment, although differences in hemodynamic management and medication use require consideration.

More recent research has examined total intravenous anaesthesia in comparison with inhalational techniques. Kolia and Man conducted a meta-analysis of randomized controlled trials and reported improvements in surgical field visibility and reductions in blood loss with propofol-based total intravenous anaesthesia in certain study populations [4]. However, the benefits appeared to depend partly on the associated opioid regimen.

A separate randomized investigation involving propofol, desflurane, and combined anaesthetic techniques did not identify meaningful differences in bleeding rates or field visibility between the three groups [5]. These findings indicate that satisfactory surgical conditions cannot be attributed to one anaesthetic agent alone.

Although lowering arterial pressure may improve visualization in some circumstances, excessive hypotension can compromise cerebral, renal, or myocardial perfusion. Therefore, blood pressure targets must be individualized according to baseline cardiovascular status and clinical risk rather than applied uniformly.

Institution-specific research examining perioperative heart rate, blood pressure, surgical visibility, and complications may provide useful information regarding current anaesthetic practices. The present study is therefore proposed to evaluate hemodynamic responses during FESS under general anaesthesia among patients treated at Mamata Medical College, Khammam.

A prospective, hospital-based observational study will be conducted jointly by the Departments of Anaesthesiology and Oto-Rhino-Laryngology, Mamata Medical College, Khammam, Telangana, India. The study will enrol adult patients scheduled for elective functional endoscopic sinus surgery under general anaesthesia. The recruitment period will be predefined, and ethical approval will be obtained before any study-specific enrolment.

2.2 Study population

Adult patients aged 18–65 years undergoing elective FESS for chronic rhinosinusitis, with or without nasal polyposis, will be considered eligible.

Inclusion criteria: Patients aged 18–65 years, ASA physical status I–III, elective FESS under general anaesthesia, and provision of written informed consent.

Exclusion criteria: Emergency procedures, uncontrolled cardiovascular instability, conditions requiring unusual hemodynamic protocols, inability to obtain reliable measurements, or simultaneous major surgical procedures likely to substantially affect intraoperative blood loss.

Patients with stable, controlled comorbidities may be included to better reflect routine clinical practice. Baseline blood pressure and cardiovascular risk factors will be documented.

2.3 Sample size determination

The sample size will be calculated according to the primary outcome, defined as the association between time-weighted intraoperative mean arterial pressure and average surgical field visibility score.

A suitable calculation for detecting an anticipated correlation will be used, incorporating the expected association from previous studies, statistical power of at least 80%, and a significance level of 0.05. Additional allowance will be made for incomplete observations or missing operative records.

2.4 Preoperative assessment

A detailed pre-anaesthetic examination will document patient demographics, body mass index, ASA physical status, medical comorbidities, medication history, and baseline cardiovascular parameters.

The ENT assessment will include the clinical diagnosis, extent of sinonasal disease, and available preoperative imaging findings. Where available, preoperative computed tomography severity will be documented using the Lund–Mackay scoring system.

Patients will undergo routine preoperative investigations as clinically indicated. Baseline systolic blood pressure, diastolic blood pressure, heart rate, and mean arterial pressure will be recorded after an appropriate resting period.

2.5 Anaesthetic management

General anaesthesia will be administered by qualified anaesthesiologists according to institutional practice. The induction agents, opioid medications, neuromuscular blockers, airway devices, maintenance technique, and medications affecting blood pressure will be recorded.

The study will not mandate deliberate hypotension or assign patients to different anaesthetic treatments. All clinical decisions, including use of vasopressors or medications for blood pressure control, will remain the responsibility of the treating anaesthesiologist.

Routine monitoring will include electrocardiography, pulse oximetry, capnography, noninvasive blood pressure measurement, and additional monitoring where clinically indicated.

2.6 Hemodynamic measurements

Heart rate, systolic blood pressure, diastolic blood pressure, and mean arterial pressure will be documented at the following intervals:

• T0: Pre-induction baseline.
• T1: Immediately after induction.
• T2: Immediately after endotracheal intubation.
• T3: Following nasal vasoconstrictor application or infiltration.
• T4: Fifteen minutes after surgery begins.
• T5: Thirty minutes after surgery begins.
• T6: Forty-five minutes after surgery begins.
• T7: End of surgery.
• T8: Immediately following extubation.

Additional measurements will be collected at five-minute intervals during active surgery to calculate time-weighted mean arterial pressure and identify transient hemodynamic events. Exact times of vasoconstrictor administration will be recorded.

2.7 Surgical field assessment

Surgical field visibility will be assessed using the Boezaart bleeding scale or another validated, predefined grading system. The operating surgeon will record surgical visibility at regular intervals.

Estimated intraoperative blood loss will be calculated using suction volume after accounting for irrigation fluid, together with the estimated contribution from blood-soaked materials. Surgical duration, intraoperative complications, and interventions required to improve visibility will be documented.

2.8 Outcome measures

The primary outcome will be the association between time-weighted intraoperative mean arterial pressure and surgical field visibility.

Secondary outcomes will include heart rate variability, maximum percentage blood pressure reduction, incidence of hypotension and bradycardia, estimated blood loss, duration of surgery, vasopressor requirement, and early postoperative complications.

2.9 Statistical analysis

Categorical variables will be presented as frequencies and percentages. Continuous variables will be summarized as mean ± standard deviation or median and interquartile range.

Repeated hemodynamic measurements will be analysed using mixed-effects models. The relationship between mean arterial pressure and surgical field visibility will be examined using appropriate correlation and regression analyses. Multivariable models will account for relevant factors such as disease severity, vasoconstrictor use, anaesthetic technique, and surgical duration.

Effect estimates, 95% confidence intervals, and p-values will be reported. The observational design will be considered when interpreting associations.

The following tables are intended for completion after collection of genuine patient-level and intraoperative monitoring data.

Table 1. Demographic and clinical characteristics of patients undergoing FESS

Table 1 will summarize the demographic distribution and baseline clinical characteristics of patients undergoing FESS. Age, sex, ASA physical status, and sinonasal disease characteristics may influence perioperative management and should be considered during interpretation of hemodynamic outcomes.

Table 2. Changes in heart rate during FESS

This table will demonstrate changes in heart rate throughout the perioperative period. Airway instrumentation and surgical stimulation may increase sympathetic activity, whereas anaesthetic medications and hemodynamic interventions may reduce heart rate. The findings will be evaluated using repeated-measures analysis to account for the correlation between observations from the same patient.

Table 3. Changes in mean arterial pressure during FESS

Table 3 will illustrate changes in mean arterial pressure during general anaesthesia and endoscopic sinus surgery. The time-weighted intraoperative MAP will be calculated using serial measurements, with attention to differences between preoperative baseline values and actual intraoperative pressures. Because excessively low arterial pressure may compromise organ perfusion, cardiovascular safety will be assessed alongside operative visibility.

Table 4. Incidence of intraoperative hemodynamic events

Table 4 will report clinically significant hemodynamic events using definitions specified before study initiation. The analysis will distinguish transient physiological variation from events requiring treatment. Individual patients may experience more than one event, so event-specific percentages may exceed 100% when combined.

Table 5. Relationship between mean arterial pressure and surgical field visibility

Table 5 will investigate the association between mean arterial pressure, surgical field visibility, and blood loss. Surgical field categories will be derived from a predefined scale, rather than created retrospectively. The analysis will help determine whether lower intraoperative MAP is associated with improved visibility in the actual study population, while taking into account vasoconstrictor use and severity of sinonasal disease.

Table 6. Intraoperative surgical outcomes

This table will summarize the overall intraoperative surgical conditions. Evaluation of estimated blood loss, duration of surgery, visibility scores, and cardiovascular measurements will allow comparison with existing literature. These outcomes should not be interpreted independently because surgical difficulty and disease severity may influence both blood loss and operative duration.

Table 7. Early postoperative outcomes and complications

Table 7 will describe selected early postoperative outcomes following FESS under general anaesthesia. Prolonged observation or intensive care admission should be interpreted according to the clinical reasons documented in each case. The analysis will help determine whether patients experiencing significant intraoperative hemodynamic events have different postoperative recovery patterns.

Hemodynamic management during functional endoscopic sinus surgery is an important component of perioperative care because cardiovascular responses may influence surgical field visibility, blood loss, and patient safety. The nasal and paranasal sinus mucosa contains an extensive vascular network, and even relatively small amounts of bleeding may interfere with visualization during endoscopic procedures. The present study is designed to evaluate patterns of heart rate and arterial blood pressure changes during FESS under general anaesthesia and examine their relationship with surgical conditions and perioperative complications.

Srivastava et al. compared esmolol and nitroglycerine for controlled hypotension during FESS in 52 patients [1]. Their study assessed surgical field quality using a standardized grading scale and examined the effectiveness of the two pharmacological approaches. The findings demonstrated that cardiovascular management and the choice of hypotensive agent can influence the operating environment. However, reductions in arterial pressure must be balanced against the requirement to preserve systemic organ perfusion.

Shams et al. conducted a randomized comparative study involving 40 patients undergoing FESS under general anaesthesia [2]. Patients received either dexmedetomidine or esmolol for controlled hypotension, and the researchers evaluated mean arterial pressure, heart rate, blood loss, surgical field conditions, and recovery characteristics. Both approaches facilitated controlled hypotension, although their pharmacological mechanisms and effects on recovery differed. The findings emphasize the importance of evaluating both hemodynamic responses and broader perioperative outcomes.

Miłoński et al. compared three anaesthetic techniques in 90 patients undergoing functional endoscopic sinus surgery [3]. Their investigation demonstrated differences in blood loss, with lower mean blood loss reported in the total intravenous anaesthesia group compared with the inhalational anaesthesia groups. The results suggest that anaesthetic technique may influence the quality of surgical conditions. However, such comparisons are affected by differences in medications, hemodynamic targets, and individual patient characteristics.

Kolia and Man conducted a meta-analysis of 12 randomized controlled trials involving 560 patients [4]. Their findings suggested that propofol-based total intravenous anaesthesia may improve surgical field visibility, reduce estimated blood loss, and shorten operative duration compared with inhalational anaesthesia. Subgroup analysis indicated that the effects were more favorable when remifentanil was used. This observation suggests that the benefits of particular anaesthetic regimens may arise from the combined effects of hypnotic and analgesic medications.

In contrast, a randomized study comparing desflurane, propofol, and a combination of both agents reported no significant differences in surgical bleeding scores or hemodynamic measurements among the groups [5]. This finding illustrates that satisfactory cardiovascular and surgical conditions can potentially be achieved through different anaesthetic approaches when blood pressure and analgesia are appropriately managed.

Additional evidence comes from Shams and colleagues and from studies examining the hemodynamic effects of local vasoconstrictor infiltration. Research involving epinephrine infiltration during FESS demonstrated that changes in mean arterial pressure and heart rate may occur shortly after administration [6]. These observations are clinically relevant because alterations following nasal infiltration may be mistakenly attributed solely to general anaesthetic drugs or surgical stimulation.

A systematic review by Hwang et al. assessed methods of reducing bleeding during endoscopic sinus surgery and highlighted the limitations of the available evidence for several perioperative interventions [7]. The investigators examined positioning, vasoconstrictor use, anesthetic management, and other strategies affecting surgical field quality. Their findings support the need for systematic evaluation of multiple factors rather than relying on a single blood pressure parameter.

More recent literature has also emphasized that the relationship between anaesthetic technique and surgical visibility remains complex. A 2023 review of perioperative management and surgical field optimization concluded that outcomes depend substantially on adjunct medications and methodological differences between studies [8]. This reinforces the importance of standardized reporting of anaesthetic drugs, vasoconstrictor administration, disease severity, and surgical conditions.

Existing research indicates that different anaesthetic techniques and pharmacological strategies may influence intraoperative blood loss and surgical field quality, although published findings are not entirely consistent. The proposed study will systematically assess changes in heart rate, mean arterial pressure, surgical field visibility, estimated blood loss, and perioperative complications. Its findings may support improvements in anaesthetic monitoring, interdisciplinary coordination, and individualized perioperative care. Definitive conclusions regarding the frequency, magnitude, and clinical consequences of hemodynamic changes in the study population will require analysis of actual patient observations.

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