The relationship between hypotension, cerebral flow, and the surgical field during endoscopic sinus surgery

Emergence characteristics comparing endotracheal tube to reinforced laryngeal mask airway during endoscopic sinus surgery - A randomised controlled study

Background and Aims

During endoscopic sinus surgery, anaesthetic conditions significantly impact the intraoperative surgical field and bleeding during emergence. While the endotracheal tube (ETT) has been traditionally used in sinus surgery, a reinforced laryngeal mask airway (RLMA) that produces less upper airway stimulation may result in smoother emergence.

Methods

A randomised controlled trial of 72 patients undergoing elective sinus surgery was conducted, with the allocation of airway technique to either ETT with a throat pack or RLMA. The primary outcome measure was emergence time, measured by time to opening eyes on commands at the cessation of anaesthesia, and the secondary outcomes were time to removal of airway device, remifentanil use, procedure times, mean arterial pressure (MAP) and the RLMA grade of blood contamination. The continuous variables were analysed using Student's t-tests and discrete variables, count tables were analysed using Fisher's exact tests.

Results

There was no significant difference in the emergence time between the ETT and RLMA groups (P = 0.83). Remifentanil use was significantly higher in the ETT group than in the RLMA group (P = 0.022). The ETT group showed a significantly increased total anaesthetic time (P = 0.01). MAP was not significant during preinduction, maintenance or post-RMLA removal. The highest grade of contamination was grade 2 in RLMA. RLMA had lower rates of postoperative adverse events.

Conclusions

RLMA comparable to ETT in terms of emergence time. The RMLA group had lower remifentanil use, anaesthesia duration and fewer postoperative adverse events such as cough and throat pain.

Does preoperative administration of hypotensive agents affect the quality of the surgical field during endoscopic sinus surgery? A triple-blind randomized controlled trial

PURPOSE

Endoscopic sinus surgery (ESS) is a surgical procedure widely used in the treatment of various sinonasal conditions. Excessive bleeding during ESS leads to potentially major complications. The primary aim of this trial was to explore any different effects of bisoprolol and nifedipine on the intraoperative surgical field. In addition, the correlations regarding surgical field state, total blood loss (TBL), mean arterial pressure (MAP), and heart rate (HR) were also examined.

METHODS

A prospective, triple-blinded, randomized, placebo-controlled trial was conducted, including 72 patients between 18 and 65 years of age who underwent ESS. As an indicator of the worst state of the intraoperative surgical field, the Boezaart scale score was used, as evaluated by two surgeons. Appropriate statistical analysis was conducted to explore score comparisons across groups and correlations between vital signs, bleeding, and the operative field state.

RESULTS

No statistically significant difference was found among different intervention groups regarding the worst state of the surgical field (p = 0.367 > 0.05). The Boezaart scale score was positively correlated with TBL (rxy = 0.619, p = 0.000 < 0.001) and MAP (rxy = 0.259, p = 0.028 < 0.05). Furthermore, MAP was positively correlated with HR (rs = 0.254, p = 0.32 < 0.05).

CONCLUSION

Our study demonstrates that preoperative administration of bisoprolol and nifedipine does not affect the worst state of the operative field. However, vital signs seem to either directly or indirectly affect bleeding and operative field state, and agents affecting them are worth exploring further.

Hemostasis in endoscopic sinus and skull base surgery

PURPOSE OF REVIEW

Bleeding during endoscopic endonasal procedures can quickly obscure critical anatomic landmarks. This increases both the difficulty of the surgical procedure and the risk of complications faced by the patient. As the indications for surgical management of sinonasal pathology grow, it is important to review techniques to minimize bleeding and facilitate safe surgery.

RECENT FINDINGS

Evidence continues to accumulate for best practices in the surgical management of sinonasal disease. Recently, international guidelines have attempted to summarize this body of evidence, lending further support to several interventions which have been advocated as methods to decrease bleeding during endoscopic endonasal surgery. Additional studies have specifically investigated the safety of certain commonly employed techniques. The utility of preoperative corticosteroid therapy and the use of total intravenous anesthetic techniques in increasingly validated. Further evidence supports the safety of reverse Trendelenburg positioning for surgical management of inflammatory disease.

SUMMARY

Recent wide scale systematic review of the literature regarding perioperative and intraoperative management of hemostasis has reinforced the utility of certain interventions, while others remain ambiguous.

Effect of Deliberate Hypotension on Regional Cerebral Oxygen Saturation During Functional Endoscopic Sinus Surgery: A Randomized Controlled Trial

Background: Deliberate hypotension can reduce bleeding and improve visualization of the surgical field during functional endoscopic sinus surgery (FESS). However, hypotension may cause brain hypoperfusion and subsequent ischemic injuries, such as delayed awakening, stroke, postoperative delirium, and postoperative cognitive dysfunction. Near-infrared spectroscopy (NIRS) can be used to monitor real-time regional cerebral oxygen saturation (rSO₂) levels to estimate brain perfusion. The present study aimed to evaluate the change in rSO₂ induced by deliberate hypotension during FESS, and assess the impact of deliberate hypotension on the surgical process.

Material and Methods: A randomized controlled trial was registered with the Chinese clinical trial registry (ChiCTR2000039846). A total of 40 patients were enrolled and randomly divided into the control and intervention groups, and finally, 39 patients were analyzed. Deliberate hypotension was induced in the intervention group using nicardipine and esmolol, whereas the control group received general anesthesia without deliberate hypotension. We recorded mean arterial pressure (MAP), saturation of pulse oximetry (SpO₂), rSO₂, and heart rate (HR) before induction of anesthesia (T0), immediately after induction of anesthesia (T1), at the beginning of the operation (corresponding with the establishment of deliberate hypotension) (T2), 10 min (T3) and 20 min (T4) after the operation began, at the end of the operation (corresponding with the end of deliberate hypotension) (T5), and 5 min (T6) and 15 min (T7) after the operation. The partial pressure of end-tidal carbon dioxide (PetCO₂) was recorded at T1, T2, T3, T4, T5, and T6. The duration of surgery, intraoperative blood loss, tracheal extubation time, and the number of patients that experienced cerebral desaturation events (CDEs) were recorded. The surgical field was estimated postoperation based on the Fromme score.

Results: A 30% decrease from the baseline MAP resulted in a decrease of intraoperative bleeding, improvement in the quality of the surgical field, and the shortening of the duration of surgery during FESS in the intervention group compared with the control group. In addition, rSO₂ was reduced and no CDEs were experienced in the intervention group. Linear regression analysis demonstrated a correlation between the decline in rSO₂ and that in MAP.

Conclusions: A decrease in MAP to a certain level will cause a decrease of rSO₂ in patients undergoing FESS under general anesthesia. Based on our findings, we recommend that the deliberate hypotensive target indicated by MAP be reduced by 30%, while PetCO₂ is maintained at 35–40 mmHg and HR is maintained at about 60 beats per minute during FESS.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

Transnasal endoscopic skull base surgery in the COVID-19 era: Recommendations for increasing the safety of the method

Transnasal endoscopic skull base surgery (eSBS) has been adopted in recent years, in great part to replace the extended procedures required by external approaches. Though sometimes perceived as "minimally invasive", eSBS still necessitates extensive manipulations within the nose/paranasal sinuses. Furthermore, exposure of susceptible cerebral structures to light and heat emanated by the telescope should be considered to comprehensively evaluate the safety of the method. While the number of studies specifically targeting eSBS safety still remains scarce, the problem has recently expanded with the SARS-CoV-2 pandemic, which also has implications for the safety of the surgical personnel. It must be stressed that eSBS may directly expose the surgeon to potentially high volumes of virus-contaminated aerosol. Thus, the anxiety of both the patient and the surgeon must be taken into account. Consequently, safety requirements must follow the highest standards. This paper summarizes current knowledge on SARS-CoV-2 biology and the peculiarities of human immunology in respect of the host-virus relationship, taking into account the latest information concerning the SARS-CoV-2 worrisome affinity for the nervous system. Based on this information, a workflow proposal is offered for consideration. This could be useful not only for the duration of the pandemic, but also during the unpredictable timeline involving our coexistence with the virus. Recommendations include technical modifications to the operating theatre, personal protective equipment, standards of testing for SARS-CoV-2 infection, prophylactic pretreatment with interferon, anti-IL6 treatment and, last but not least, psychological support for the patient.

Perioperative management of endoscopic transsphenoidal pituitary surgery

The contemporary embrace of endoscopic technology in the approach to the anterior skull base has altered the perioperative landscape for patients requiring pituitary surgery. Utility of a multi-disciplinary unit in management decisions facilitates the delivery of optimal care. Evolution of technology and surgical expertise in pituitary surgery mandates ongoing review of all components of the care central to these patients. The many areas of potential variability in the pre, intra and post-operative timeline of pituitary surgery are readily identifiable. Core undertakings and contemporary controversies in the peri-operative management of patients undergoing endoscopic transsphenoidal pituitary surgery are assessed against the available literature with a view to providing guidance for the best evidence-based practice.

Hemodynamic changes in patients undergoing office-based sinus procedures under local anesthesia

BACKGROUND

The objective of this study is to characterize changes in hemodynamics, pain, and anxiety during office-based endoscopic sinus procedures performed under local anesthesia.

METHODS

We conducted a prospective study of adults undergoing in-office endoscopic sinus procedures under local anesthesia. Patients with American Society of Anesthesiologists (ASA) Physical Status Classification System class 1 or 2 were included. Anesthesia was administered by topical 4% lidocaine/oxymetazoline and submucosal injection of 1% lidocaine/1:200,000 epinephrine. Vital signs and pain were measured at baseline, postinjection, and 5-minute intervals throughout the procedure. Anxiety levels were scored using the State-Trait Anxiety Inventory (STAI). Univariate and multivariate regression analyses were performed to identify factors significantly associated with changes in each hemodynamic metric.

RESULTS

Twenty-five patients were studied. This cohort was 52% male, mean age of 57.8 ± 14.4 years, and Charlson Comorbidity Index (CCI) median of 2. Mean procedure duration was 25.0 ± 10.3 minutes. Mean maximal increase in systolic blood pressure (SBP) was 24.6 ± 17.8 mmHg from baseline. Mean maximal heart rate increase was 22.8 ± 10.8 beats per minute (bpm) from baseline. In multivariate regression analysis, when accounting for patient age, cardiac comorbidity, CCI, and ASA, older age was significantly associated with an increase of >20 mmHg in SBP (p = 0.043). Mean pain score during procedures was 1.5 ± 1.3 with a mean maximum of 4.0 ± 2.6. STAI anxiety scores did not change significantly from preprocedure to postprocedure (32.8 ± 11.6 to 31.0 ± 12.6, p = 0.46). No medical complications occurred.

CONCLUSION

Although patients appear to tolerate office procedures well, providers should recognize the potential for significant fluctuations in blood pressure during the procedure, especially in older patients.

Comparison of the effect of propofol and desflurane on S-100β and GFAP levels during controlled hypotension for functional endoscopic sinus surgery: A randomized controlled trial

BACKGROUND

Although surgical field visualization is important in functional endoscopic sinus surgery (FESS), the complications associated with controlled hypotension for surgery should be considered. Intraoperative hypotension is associated with postoperative stroke, leading to subsequent hypoxia with potential neurologic injury. We investigated the effect of propofol and desflurane anesthesia on S-100β and glial fibrillary acidic protein (GFAP) levels which are early biomarkers for cerebral ischemic change during controlled hypotension for FESS.

METHODS

For controlled hypotension during FESS, anesthesia was maintained with propofol/remifentanil in propofol group (n = 30) and with desflurane/remifentanil in desflurane group (n = 30). For S-100β and GFAP assay, blood samples were taken at base, 20 and 60 minutes after achieving the target range of mean arterial pressure, and at 60 minutes after surgery.

RESULTS

The base levels of S-100β were 98.04 ± 78.57 and 112.61 ± 66.38 pg/mL in the propofol and desflurane groups, respectively. The base levels of GFAP were 0.997 ± 0.486 and 0.898 ± 0.472 ng/mL in the propofol and desflurane groups, respectively. The S-100β and GFAP levels were significantly increased in the study period compared to the base levels in both groups (P ≤ .001). There was no significant difference at each time point between the 2 groups.

CONCLUSION

On comparing the effects of propofol and desflurane anesthesia for controlled hypotension on the levels of S-100β and GFAP, we noted that there was no significant difference in S-100β and GFAP levels between the 2 study groups.

CLINICAL TRIAL REGISTRATION

Available at: http://cris.nih.go.kr, KCT0002698.

Anesthesia for functional endoscopic sinus surgery

PURPOSE OF REVIEW

The present article summarizes anesthetic techniques used during functional endoscopic sinus surgery to decrease bleeding and aid in creating a clear surgical field. The applicable physiology behind these anesthetic techniques is reviewed with emphasis on the effect on bleeding and the surgical field. Deliberate hypotension, reverse Trendelenburg positioning, regional anesthesia, and cerebral monitoring are discussed.

RECENT FINDINGS

There are mixed data as to whether traditional inhalation anesthesia or total intravenous anesthesia is superior with respect to better surgical fields and decreased blood loss. A review of the literature tends to favor total intravenous anesthesia. Cerebral oximetry and transcranial Doppler ultrasound are emerging techniques to monitor cerebral perfusion during deliberate hypotension.

SUMMARY

Total intravenous anesthesia using propofol and remifentanil is the current favored technique for producing deliberate hypotension during endoscopic sinus surgery due to its hemodynamic stability and smooth rapid emergence.

Evaluation of cerebral oxygen saturation during hypotensive anesthesia in functional endoscopic sinus surgery

Background and Aims

Controlled hypotensive anesthesia in endoscopic sinus surgery would provide a clean surgical field. Cerebral oxygen saturation (ScO₂) is important in endoscopic sinus surgery patients and it may be low during controlled hypotension. The aim of the present study was to assess ScO₂ in these patients.

Material and Methods

In this observational study, 41 patients who underwent endoscopic sinus surgery with hypotensive anesthesia were enrolled for the study and all of the patients received the same anesthetic medication, nitroglycerin for controlled hypotension. Variables were measured prior to surgery, after induction of anesthesia, 5 min, and every 30 min after controlled hypotension. Near-infrared spectroscopy was used for ScO₂ evaluation. Mean arterial blood pressure (MAP) was maintained at 55-60 mmHg in the surgical duration. We used t-test, Wilcoxon, and repeated measures analysis of variance (ANOVA). We examined the cross-correlation functions of the time series data between end-tidal carbon dioxide (ETCO₂)/MAP and ScO₂.

Results

The mean of intraoperative ScO₂ was not significantly different from the baseline evaluation (P > 0.05). ETCO₂ was cross correlated with current ScO₂ [r: 0.618, confidence interval (CI) 95%: 0.46-0.78]. We found moderate cross correlation between the MAP and current ScO₂ (r: 0.728, CI 95%: 0.56-0.88). About 92% of the patients recovered within 30 min. Recovery time was associated with intraoperative MAP (P: 0.004, r: 0.438), intraoperative ETCO₂ (P: 0.003, r: 0.450), and ScO₂ (P: 0.026, r: 0.348).

Conclusions

Based on our findings, the assessment of ScO₂ and maintained MAP >55 mmHg may provide safe conditions for endoscopic sinus surgery.

Range of S-100β levels during functional endoscopic sinus surgery with moderately controlled hypotension

The aim of this study is to determine the range of S-100β levels during functional endoscopic sinus surgery (FESS) when the mean arterial pressure (MAP) was controlled within 60-70 mmHg. After anesthesia induction with propofol and remifentanil, the patient was positioned in the reverse Trendelenburg position and MAP was controlled within 60-70 mmHg during surgery. For the S-100β assay, blood was taken from a radial arterial catheter before (baseline) and at 20 (T ₂₀) and 60 (T ₆₀) min after setting the reverse Trendelenburg position and controlled hypotension, and at 60 (T _post60) min after the end of the operation. In total, 34 patients completed the study. Baseline S-100β was 0.00837 ± 0.00785 ng/mL. The levels at T ₂₀ and T ₆₀ were 0.02057 ± 0.01739 and 0.01987 ± 0.01145 ng/mL, respectively. The level of T _post60 was 0.05436 ± 0.02318 ng/mL. The level at T ₂₀ increased significantly versus the baseline level (P < 0.001); there were no significant differences between T ₂₀ and T ₆₀. The level at T _post60 was significantly different versus T ₂₀ and T ₆₀ (P < 0.001). However, all S-100β levels were within the normal range. S-100β-a sensitive biomarker of cerebral ischemia-was within the normal range during FESS when moderate hypotension (MAP >60 mmHg) was provided. Thus, moderate hypotension would be seemed to be a safe and effective anesthetic technique for FESS without risk for cerebral ischemia.

Hemostasis in sinus surgery

PURPOSE OF REVIEW

Optimization of the surgical field involves a complex interplay of many factors. Although it is agreed that hemostasis is critical to safe, efficient, and successful sinus surgery, a lack of consensus exists as to the best way to achieve it. This review examines the current body of evidence supporting many of the practices surgeons believe to influence hemostasis.

RECENT FINDINGS

Although many of the practices discussed in this article have long been considered to influence hemostasis, it is not until recently that high-level evidence supporting their use has been available. Well designed studies now exist supporting the preoperative use of oral steroids in polyp patients, the importance of adequate reverse trendelenburg positioning, the use of flexible laryngeal mask ventilation during general anesthesia, and the increased safety and comparable efficacy of topical epinephrine over other topical and injectable agents. Controversy still exists as to the ideal method of achieving controlled hypotensive anesthesia, although new evidence has emerged as to what hemodynamic parameters should be adhered to, to reduce the risk of cerebral hypoperfusion.

SUMMARY

Numerous factors influence hemostasis and so it is important that ENT surgeons have a sound understanding of the evidence supporting their everyday surgical practice. Improved standardization of scoring and reporting of bleeding may increase the power of research studies to draw more definitive conclusions about the role that certain factors have on hemostasis.

Strategies for Improving Visualization During Endoscopic Skull Base Surgery

The nasal cavity has a robust vascular supply, and bleeding is a primary obstacle to the minimally invasive skull base technique. Venous bleeding, including the cavernous sinus, can be managed with various techniques using hemostatic materials and pressure. A thorough understanding of the skull base vascular anatomy is vital for avoiding injury to major arteries and having confidence to control venous bleeding to optimize the endoscopic view and tumor resection.

Hemorrhagic Complications of Endoscopic Sinus Surgery

Major complications during endoscopic sinus surgery are rare and occur in 0.36% to 3.1% of patients. Postoperative hemorrhage accounts for 23% to 39% of complications. Despite being rare, major hemorrhage can be serious for the patient. This article discusses hemorrhagic complications during and following endoscopic sinus surgery, focusing on a review of the surgical anatomy, common pitfalls to avoid, preventative measures, and management of certain catastrophic complications for which preparedness can mean the difference between life and death.

The effect of blood pressure and cardiac output on the quality of the surgical field and middle cerebral artery blood flow during endoscopic sinus surgery

BACKGROUND

A clear surgical field is critical during endoscopic sinus surgery (ESS). Hypotensive anesthesia and cardiac output (CO) may optimize the surgical field; however, evidence of their effect on bleeding and cerebral blood flow is conflicting. The aim of this study was to evaluate the effect of blood pressure (BP) and CO on intraoperative bleeding and middle cerebral artery blood flow velocity (Vmca ) during ESS.

METHODS

This was a prospective randomized controlled trial. Patients undergoing ESS for chronic rhinosinusitis at a tertiary institution in 2013 were randomized to receive BP manipulation using target-controlled noradrenaline infusion during surgery to either their left or right sinuses. The contralateral side in each patient served as control. Bleeding was scored using a 0 to 10 point bleeding assessment scale (BAS, 0-10) and Vmca was measured using transcranial Doppler ultrasonography every 10 minutes or when surgically opportune, and time-matched with BP and CO. Data was analyzed using Bland-Altman methods.

RESULTS

A total of 105 time points were collected across a mean arterial pressure (MAP) range of 32 to 118 mmHg. Significant correlations were demonstrated between MAP and Vmca (r = 0.7, p < 0.0001), MAP and BAS (r = 0.50, p < 0.0001), CO and Vmca (r = 0.57, p < 0.0001), and CO and BAS (r = 0.42, p < 0.0001). The best surgical fields were seen at 40 to 59 mmHg MAP. However, MAP below 60 mmHg produced >50% reduction in Vmca in more than 10% of time points.

CONCLUSION

Balancing surgical visibility with organ perfusion remains a challenge. The results of this study show that moderate hypotension significantly improves the surgical field; however reducing BP below 60 mmHg may risk cerebral hypoperfusion.

Anaesthesia for Endoscopic Sinus Surgery: A Survey of Anaesthesiologists in Restructured Hospitals in Singapore

Introduction:

A cross-sectional survey of anaesthesiologists in Singapore's restructured hospitals was conducted to explore strategies employed to obtain a bloodless surgical field during endoscopic sinus surgery.

Methods:

All practicing anaesthesiologists in public institutions in Singapore were invited to answer an anonymous questionnaire. A point of contact per institution assisted in distribution and collection of questionnaire forms over a nine-month period.

Results:

A total of 114 anaesthesiologists completed the survey (response rate 60%). It was observed that 64.9% of respondents do not routinely employ controlled hypotension for endoscopic sinus surgery. Sixty-seven point five per cent chose general anaesthesia without nitrous oxide as the preferred anaesthetic technique for endoscopic sinus surgery. Forty-seven point four per cent opined that anaesthetic technique made no significant difference to outcomes in endoscopic sinus surgery. The most commonly used narcotics in endoscopic sinus surgery by the respondents were morphine (59.6%) and fentanyl (54.4%). However, where total intravenous anaesthesia was adopted, 86.0% of respondents opted to use remifentanil. The most commonly used class of antihypertensives for controlled hypotension was beta-blockers (66.7%). Factors limiting the use of total intravenous anaesthesia were also explored.

Conclusion:

This survey identifies variations from current evidence in the anaesthetic management of endoscopic sinus surgery among anaesthesiologists in Singapore's public institutions. The reasons behind these variations, which could include surgical preferences, financial, logistical, cultural, and educational factors, should be explored and any issues found addressed as necessary.