{"title":"[Small tidal volume hyperventilation relieves intraocular and intracranial pressure elevation in prone spinal surgery: a randomized controlled trial].","authors":"X Duan, J Wei, A Liang, X Ji","doi":"10.12122/j.issn.1673-4254.2024.04.06","DOIUrl":null,"url":null,"abstract":"<p><strong>Objective: </strong>To investigate the effects of different ventilation strategies on intraocular pressure (IOP) and intracranial pressure in patients undergoing spinal surgery in the prone position under general anesthesia.</p><p><strong>Methods: </strong>Seventy-two patients undergoing prone spinal surgery under general anesthesia between November, 2022 and June, 2023 were equally randomized into two groups to receive routine ventilation (with Vt of 8mL/kg, Fr of 12-15/min, and etCO<sub>2</sub> maintained at 35-40 mmHg) or small tidal volume hyperventilation (Vt of 6 mL/kg, Fr of18-20/min, and etCO<sub>2</sub> maintained at 30-35 mmHg) during the surgery. IOP of both eyes (measured with a handheld tonometer), optic nerve sheath diameter (ONSD; measured at 3 mm behind the eyeball with bedside real-time ultrasound), circulatory and respiratory parameters of the patients were recorded before anesthesia (T<sub>0</sub>), immediately after anesthesia induction (T<sub>1</sub>), immediately after prone positioning (T<sub>2</sub>), at 2 h during operation (T<sub>3</sub>), immediately after supine positioning after surgery (T<sub>4</sub>) and 30 min after the operation (T<sub>5</sub>).</p><p><strong>Results: </strong>Compared with those at T<sub>1</sub>, IOP and ONSD in both groups increased significantly at T<sub>3</sub> and T<sub>4</sub>(<i>P</i> < 0.05). IOP was significantly lower in hyperventilation group than in routine ventilation group at T<sub>3</sub> and T<sub>4</sub>(<i>P</i> < 0.05), and ONSD was significantly lower in hyperventilation group at T<sub>4</sub>(<i>P</i> < 0.05). IOP was positively correlated with the length of operative time (<i>r</i>=0.779, <i>P</i> < 0.001) and inversely with intraoperative etCO<sub>2</sub> at T<sub>3</sub>(<i>r</i>=-0.248, <i>P</i> < 0.001) and T<sub>4</sub>(<i>r</i>=-0.251, <i>P</i> < 0.001).ONSD was correlated only with operation time (<i>r</i>=0.561, <i>P</i> < 0.05) and not with IOP (<i>r</i>=0.178, <i>P</i>>0.05 at T<sub>3</sub>; <i>r</i>=0.165, <i>P</i>>0.05 at T<sub>4</sub>).</p><p><strong>Conclusion: </strong>Small tidal volume hyperventilation can relieve the increase of IOP and ONSD during prone spinal surgery under general anesthesia.</p>","PeriodicalId":18962,"journal":{"name":"Nan fang yi ke da xue xue bao = Journal of Southern Medical University","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11073951/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nan fang yi ke da xue xue bao = Journal of Southern Medical University","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.12122/j.issn.1673-4254.2024.04.06","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Medicine","Score":null,"Total":0}
引用次数: 0
Abstract
Objective: To investigate the effects of different ventilation strategies on intraocular pressure (IOP) and intracranial pressure in patients undergoing spinal surgery in the prone position under general anesthesia.
Methods: Seventy-two patients undergoing prone spinal surgery under general anesthesia between November, 2022 and June, 2023 were equally randomized into two groups to receive routine ventilation (with Vt of 8mL/kg, Fr of 12-15/min, and etCO2 maintained at 35-40 mmHg) or small tidal volume hyperventilation (Vt of 6 mL/kg, Fr of18-20/min, and etCO2 maintained at 30-35 mmHg) during the surgery. IOP of both eyes (measured with a handheld tonometer), optic nerve sheath diameter (ONSD; measured at 3 mm behind the eyeball with bedside real-time ultrasound), circulatory and respiratory parameters of the patients were recorded before anesthesia (T0), immediately after anesthesia induction (T1), immediately after prone positioning (T2), at 2 h during operation (T3), immediately after supine positioning after surgery (T4) and 30 min after the operation (T5).
Results: Compared with those at T1, IOP and ONSD in both groups increased significantly at T3 and T4(P < 0.05). IOP was significantly lower in hyperventilation group than in routine ventilation group at T3 and T4(P < 0.05), and ONSD was significantly lower in hyperventilation group at T4(P < 0.05). IOP was positively correlated with the length of operative time (r=0.779, P < 0.001) and inversely with intraoperative etCO2 at T3(r=-0.248, P < 0.001) and T4(r=-0.251, P < 0.001).ONSD was correlated only with operation time (r=0.561, P < 0.05) and not with IOP (r=0.178, P>0.05 at T3; r=0.165, P>0.05 at T4).
Conclusion: Small tidal volume hyperventilation can relieve the increase of IOP and ONSD during prone spinal surgery under general anesthesia.