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Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery

OBJECTIVES: The effects of hypercapnia on regional cerebral oxygen saturation (rSO(2)) during surgery are unclear. We conducted a randomised controlled trial to investigate the relationship between mild hypercapnia and rSO(2). We hypothesised that, compared with targeted normocapnia (TN), targeted m...

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Autores principales: Wong, Clarence, Churilov, Leonid, Cowie, Dean, Tan, Chong Oon, Hu, Raymond, Tremewen, David, Pearce, Brett, Pillai, Param, Karalapillai, Dharshi, Bellomo, Rinaldo, Weinberg, Laurence
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BMJ Publishing Group 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7045198/
https://www.ncbi.nlm.nih.gov/pubmed/32066598
http://dx.doi.org/10.1136/bmjopen-2019-029159
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author Wong, Clarence
Churilov, Leonid
Cowie, Dean
Tan, Chong Oon
Hu, Raymond
Tremewen, David
Pearce, Brett
Pillai, Param
Karalapillai, Dharshi
Bellomo, Rinaldo
Weinberg, Laurence
author_facet Wong, Clarence
Churilov, Leonid
Cowie, Dean
Tan, Chong Oon
Hu, Raymond
Tremewen, David
Pearce, Brett
Pillai, Param
Karalapillai, Dharshi
Bellomo, Rinaldo
Weinberg, Laurence
author_sort Wong, Clarence
collection PubMed
description OBJECTIVES: The effects of hypercapnia on regional cerebral oxygen saturation (rSO(2)) during surgery are unclear. We conducted a randomised controlled trial to investigate the relationship between mild hypercapnia and rSO(2). We hypothesised that, compared with targeted normocapnia (TN), targeted mild hypercapnia (TMH) during major surgery would increase rSO(2). DESIGN: A prospective, randomised, controlled trial in adult participants undergoing elective major surgery. SETTING: A single tertiary centre in Heidelberg, Victoria, Australia. PARTICIPANTS: 40 participants were randomised to either a TMH or TN group (20 to each). INTERVENTIONS: TMH (partial pressure of carbon dioxide in arterial blood, PaCO(2), 45–55 mm Hg) or TN (PaCO(2) 35–40 mm Hg) was delivered via controlled ventilation throughout surgery. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary endpoint was the absolute difference between the two groups in percentage change in rSO(2) from baseline to completion of surgery. Secondary endpoints included intraoperative pH, bicarbonate concentration, base excess, serum potassium concentration, incidence of postoperative delirium and length of stay (LOS) in hospital. RESULTS: The absolute difference between the two groups in percentage change in rSO(2) from the baseline to the completion of surgery was 19.0% higher in both hemispheres with TMH (p<0.001). On both sides, the percentage change in rSO(2) was greater in the TMH group than the TN group throughout the duration of surgery. The difference between the groups became more noticeable over time. Furthermore, postoperative delirium was higher in the TN group (risk difference 0.3, 95% CI 0.1 to 0.5, p=0.02). LOS was similar between groups (5 days vs 5 days; p=0.99). CONCLUSION: TMH was associated with a stable increase in rSO(2) from the baseline, while TN was associated with a decrease in rSO(2) in both hemispheres in patients undergoing major surgery. This resulted in a clear separation of percentage change in rSO(2) from the baseline between TMH and TN over time. Our findings provide the rationale for larger studies on TMH during surgery. TRIAL REGISTRATION NUMBER: The Australian New Zealand Clinical Trials Registry (ACTRN12616000320459).
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spelling pubmed-70451982020-03-09 Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery Wong, Clarence Churilov, Leonid Cowie, Dean Tan, Chong Oon Hu, Raymond Tremewen, David Pearce, Brett Pillai, Param Karalapillai, Dharshi Bellomo, Rinaldo Weinberg, Laurence BMJ Open Anaesthesia OBJECTIVES: The effects of hypercapnia on regional cerebral oxygen saturation (rSO(2)) during surgery are unclear. We conducted a randomised controlled trial to investigate the relationship between mild hypercapnia and rSO(2). We hypothesised that, compared with targeted normocapnia (TN), targeted mild hypercapnia (TMH) during major surgery would increase rSO(2). DESIGN: A prospective, randomised, controlled trial in adult participants undergoing elective major surgery. SETTING: A single tertiary centre in Heidelberg, Victoria, Australia. PARTICIPANTS: 40 participants were randomised to either a TMH or TN group (20 to each). INTERVENTIONS: TMH (partial pressure of carbon dioxide in arterial blood, PaCO(2), 45–55 mm Hg) or TN (PaCO(2) 35–40 mm Hg) was delivered via controlled ventilation throughout surgery. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary endpoint was the absolute difference between the two groups in percentage change in rSO(2) from baseline to completion of surgery. Secondary endpoints included intraoperative pH, bicarbonate concentration, base excess, serum potassium concentration, incidence of postoperative delirium and length of stay (LOS) in hospital. RESULTS: The absolute difference between the two groups in percentage change in rSO(2) from the baseline to the completion of surgery was 19.0% higher in both hemispheres with TMH (p<0.001). On both sides, the percentage change in rSO(2) was greater in the TMH group than the TN group throughout the duration of surgery. The difference between the groups became more noticeable over time. Furthermore, postoperative delirium was higher in the TN group (risk difference 0.3, 95% CI 0.1 to 0.5, p=0.02). LOS was similar between groups (5 days vs 5 days; p=0.99). CONCLUSION: TMH was associated with a stable increase in rSO(2) from the baseline, while TN was associated with a decrease in rSO(2) in both hemispheres in patients undergoing major surgery. This resulted in a clear separation of percentage change in rSO(2) from the baseline between TMH and TN over time. Our findings provide the rationale for larger studies on TMH during surgery. TRIAL REGISTRATION NUMBER: The Australian New Zealand Clinical Trials Registry (ACTRN12616000320459). BMJ Publishing Group 2020-02-16 /pmc/articles/PMC7045198/ /pubmed/32066598 http://dx.doi.org/10.1136/bmjopen-2019-029159 Text en © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. http://creativecommons.org/licenses/by-nc/4.0/This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
spellingShingle Anaesthesia
Wong, Clarence
Churilov, Leonid
Cowie, Dean
Tan, Chong Oon
Hu, Raymond
Tremewen, David
Pearce, Brett
Pillai, Param
Karalapillai, Dharshi
Bellomo, Rinaldo
Weinberg, Laurence
Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery
title Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery
title_full Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery
title_fullStr Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery
title_full_unstemmed Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery
title_short Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery
title_sort randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients undergoing major surgery
topic Anaesthesia
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7045198/
https://www.ncbi.nlm.nih.gov/pubmed/32066598
http://dx.doi.org/10.1136/bmjopen-2019-029159
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