The Effect of Retrobulbar Block for Eye Surgery on Brain Oxygenation and Cognitive Functions in Elderly Patients

Study Overview
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Brief Summary
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The investigators measured changes in cerebral oxygen saturation (rSO2) and MMSE scores after retrobulbar block performed with levobupivacaine and lidocaine in patients undergoing vitreoretinal surgery.A total of 66 patients over the age of 60 undergoing vitreoretinal surgery with a total duration of less than 1 hour were included in this prospective, double-blinded study. The patients were randomly divided into two groups: group L (5ml, 2% lidocaine) and group LB (5ml, 0.5% levobupivacaine). Bilateral rSO2 measurements were recorded before the retrobulbar block and at 1-5 minutes post-block, during the procedure, and at 10-40 minutes post-op. MMSE was performed preoperatively and postoperatively in order to evaluate short term cognitive function. Sensory and motor block durations, pain, akinesia and conjunctival feeling scores, patient-surgeon satisfaction, and complications were also recorded.

Detailed Description
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A total of 66 patients undergoing vitreoretinal surgery (total duration < 60 minutes) using retrobulbar block, who were classified as category I-III according to the ASA (American Society of Anesthesiologists) Classification system, who were over the age of 60, and who had no cognitive dysfunction were included in the study. Exclusion criteria were as follows: contraindication for retrobulbar block, preoperative systolic blood pressure of 180 mmHg, diastolic blood pressure of above 100 mmHg, uncontrolled diabetes, body mass index ≥ 30 kg/m2, MMSE ≤ 24, advanced organ failure, or Hb < 9gr/dl.The patients were randomly divided into two groups using a sealed-envelope method: Group L: Patients undergoing block with lidocaine (n = 33) Group LB: Patients undergoing block with levobupivacaine (n = 33) The patients did not undergo premedication in order to accommodate the postoperative MMSE evaluation. For intra-operative sedation, remifentanil (UltivaR, GlaxoSmithKline, Berntford, UK) was initiated as an infusion at a dose range of 0.05-0.1 mcg/kg/min. The mean arterial pressure and heart rate values were allowed to vary up to 20% of the preoperative values of the patients. For this purpose, the remifentanil infusion rate was increased or decreased at the determined dose interval. Retrobulbar block was performed with 5 ml of 2% lidocaine hydrochloride (AritmalR, Osel, Istanbul, Turkey) in Group L patients and 5ml of 0.5% levobupivacaine (ChirocaineR, Abbvie, Chicago, USA) in Group LB patients. The block was performed by the same practitioner (fourth year assistant of Ophthalmology Department) using inferotemporal approach as described by Sanderson using 27 gage disposable needles (Atkinson Retrobulbar NeedleR, Asico, USA). Sensory and motor block onset and end times and akinesia score were recorded. The mean arterial pressure (MAP), heart rate (HR), and oxygen saturation (SpO2) were recorded in the preoperative period, at minutes 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 intra-operatively, and at 10, 20, 30, and 40 minutes postoperatively in the recovery room. . The patients were transferred to the operating table for measurement of bilateral rSO2, and preoxygenation was performed for three minutes using 4 L/min 100% oxygen via nasal cannula. The basal oxygenation values were determined by taking the average of the last 30 s measurements. The rSO2 values were recorded at 1, 3, 5, 10, 15, 20, 25, 30th, 35, 40, 45, 50, 55, and 60 minutes after retrobulbar block, and at 10, 20, 30, and 40 minutes after the completion of the procedure. Cognitive functions were assessed by the same technician using MMSE in the preoperative period, 40 minutes postoperatively and at 7 days after the operation (short term).Surgeon satisfaction was queried at the end of the case and patient satisfaction was questioned at the end of day.

Official Title
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The Effect of Retrobulbar Block on Bi-Hemispheric Cerebral Oxygen Saturation and Early Period Postoperative Cognitive Functions With Lidocaine and Levobupivacaine in Elderly Patients With Ophthalmic Surgery

Conditions
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Vitreoretinal Surgery, Cognitive Function Abnormal, Intraoperative Monitoring

Intervention / Treatment
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* Drug: 2% lidocaine hydrochloride
* Drug: 0.5% levobupivacaine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Undergoing vitreoretinal surgery (total duration < 60 minutes) The ASA (American Society of Anesthesiologists) Classification I-III Over the age of 60 The patiens who had no cognitive dysfunction Exclusion Criteria: Contraindication for retrobulbar block Preoperative systolic blood pressure of 180 mmHg, diastolic blood pressure of above 100 mmHg Uncontrolled diabetes Body mass index ≥ 30 kg/m2 MMSE ≤ 24 Advanced organ failure Hb < 9gr/dl

Ages Eligible for Study
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Minimum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group L<br>Patients undergoing block with 2% lidocaine hydrochloride | Drug: 2% lidocaine hydrochloride<br>* Retrobulbar block was performed with 5 ml of 2% lidocaine hydrochloride (AritmalR, Osel, Istanbul, Turkey) in Group L patients. The block was performed by the same practitioner (fourth year assistant of Ophthalmology Department) using inferotemporal approach as described by Sanderson using 27 gage disposable needles (Atkinson Retrobulbar NeedleR, Asico, USA)<br>|
| Active Comparator: Group LB<br>Patients undergoing block with 0.5% levobupivacaine | Drug: 0.5% levobupivacaine<br>* and 5ml of 0.5% levobupivacaine (ChirocaineR, Abbvie, Chicago, USA) in Group LB patients. The block was performed by the same practitioner (fourth year assistant of Ophthalmology Department) using inferotemporal approach as described by Sanderson using 27 gage disposable needles (Atkinson Retrobulbar NeedleR, Asico, USA)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cerebral oxygen saturation changes (rSO2) | The NIRS device probes (INVOS-3100AR; Somanetics Inc., Troy, MI, USA) were placed at least 2 cm above the eyebrows and 3 cm away from the mid-line of the forehead, on right and left, in accordance with the instructions of manufacturer.The patient's forehead was cleaned with acetone alcohol before the sensor pads were glued, and wrapped with a bandage so that the sensors were not affected by ambient light. The patients were transferred to the operating table for measurement of bilateral rSO2, and preoxygenation was performed for three minutes using 4 L/min 100% oxygen via nasal cannula. | The rSO2 value changes were recorded from baseline up to 40 minutes after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cognitive function measurement | Cognitive functions were assessed by the same technician using the Mini Mental State Examination (MMSE) test. | Cognitive functions were assessed from baseline up to 7 days after the surgery | 
| Sensory block onset time by the conjunctival feeling score using the cotton contact test. | The sensory block onset time was recorded as the moment when the patient did not feel a piece of cotton touching the cornea. This time was measured by the conjunctival feeling score using the cotton contact test (0: normal, 1: less sensitive, 2: complete sensory loss). Score of 2 on the scale was considered as onset time for sensory block. | The sensory block onset time was recorded at the beginning of surgery till the first 15 min | 
| Sensory block end time by the conjunctival feeling score using the cotton contact test. | The time at which recovery of sensory block was recovered was measured by the conjunctival feeling score using the cotton contact test (0: normal, 1: less sensitive, 2: complete sensory loss). Score of 0 on the scale was considered as end time for sensory block. | The sensory block end time was recorded at the end of surgery till the first 24 h | 
| Motor block onset time by eye movements score. | The motor block onset time was recorded as the time that the patient's eye movements score was four or less. Eye movements score was measured over three points in each of the four quadrants as follows: 3, full eye movement and 0, no movement. | The motor block onset time was recorded at the beginning of surgery till the first 15 min | 
| Motor block end time by eye movements score. | The time at which recovery of motor block was recovered was measured by the eye movements score (three points in each of the four quadrants as follows: 3, full eye movement and 0, no movement). Score of 12 on the scale was considered as end time for motor block. | The motor block end time was recorded at the end of surgery till the first 24 h | 
| The akinesia score measurement | The akinesia score was assessed between 0-12 points after 10 minutes of block application. Eye movements were measured over three points in each of the four quadrants as follows: 3, full eye movement and 0, no movement. The sum of the movement scores across all four quadrants was recorded as the akinesian score. An eye with full movement was scored as 12, and an immobile eye was scored as 0. If the akinesia score was four or less, the block was considered successful. | The akinesia score was assessed at the beginning of surgery till the first 15 min. | 
| The mean arterial pressure (MAP) measurement | The mean arterial pressure (MAP) was recorded in the preoperative period, at minutes 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 intra-operatively, and at 10, 20, 30, and 40 minutes postoperatively in the recovery room. | The mean arterial pressure was recorded from baseline up to 40 minutes after surgery | 
| The heart rate (HR) measurement | The heart rate (HR) was recorded in the preoperative period, at minutes 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 intra-operatively, and at 10, 20, 30, and 40 minutes postoperatively in the recovery room. | The heart rate (HR) was recorded from baseline up to 40 minutes after surgery | 
| The oxygen saturation (SpO2) measurement | The oxygen saturation (SpO2) was recorded in the preoperative period, at minutes 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, and 60 intra-operatively, and at 10, 20, 30, and 40 minutes postoperatively in the recovery room. | The oxygen saturation (SpO2) was recorded from baseline up to 40 minutes after surgery | 
| Surgeon satisfaction | They were asked to score over 10 point scale. Surgeon satisfaction was evaluated using 10 point scale ( 0 = not satisfied at all and 10 = very satisfied) | Surgeon satisfaction was queried at the end of the surgery till the first 15 min. | 
| Patient satisfaction | They were asked to score over 10 point scale. Patient satisfaction was evaluated using 10 point scale ( 0 = not satisfied at all and 10 = very satisfied) | Patient satisfaction was questioned 24 hours after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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NIR spectroscopy, cognitive function, eye, nerve block