biostudies-literatureUnknown18Karlsen HSouth-Eastern Norway Regional Health AuthorityLaerdal Foundation For Acute MedicineZOLL Foundation<h4>Aim</h4>To determine whether targeting mild hypercapnia (PaCO₂ 7 kPa) would yield improved cerebral blood flow and metabolism compared to normocapnia (PaCO₂ 5 kPa) with and without targeted temperature management to 33 °C (TTM33) in a porcine post-cardiac arrest model.<h4>Methods</h4>39 pigs were resuscitated after 10 minutes of cardiac arrest using cardiopulmonary bypass and randomised to TTM33 or no-TTM, and hypercapnia or normocapnia. TTM33 was managed with intravasal cooling. Animals were stabilized for 30 minutes followed by a two-hour intervention period. Hemodynamic parameters were measured continuously, and neuromonitoring included intracranial pressure (ICP), pressure reactivity index, cerebral blood flow, brain-tissue pCO₂ and microdialysis. Measurements are reported as proportion of baseline, and areas under the curve during the 120 min intervention period were compared.<h4>Results</h4>Hypercapnia increased cerebral flow in both TTM33 and no-TTM groups, but also increased ICP (199% vs. 183% of baseline, <i>p</i> = 0.018) and reduced cerebral perfusion pressure (70% vs. 84% of baseline, <i>p</i> < 0.001) in no-TTM animals. Cerebral lactate (196% vs. 297% of baseline, <i>p</i> < 0.001), pyruvate (118% vs. 152% of baseline, <i>p</i> < 0.001), glycerol and lactate/pyruvate ratios were lower with hypercapnia in the TTM33 group, but only pyruvate (133% vs. 150% of baseline, <i>p</i> = 0.002) was lower with hypercapnia among no-TTM animals.<h4>Conclusion</h4>In this porcine post-arrest model, hypercapnia led to increased cerebral flow both with and without hypothermia, but also increased ICP and reduced cerebral perfusion pressure in no-TTM animals. The effects of hypercapnia were different with and without TTM.(Institutional protocol number: FOTS, id 14931).Resuscitation plus100604https://www.ebi.ac.uk/biostudies/studies/S-EPMC10950799biostudies-literatureCerebral perfusion and metabolism with mild hypercapnia vs. normocapnia in a porcine post cardiac arrest model with and without targeted temperature management.PMC10950799Karlsen HSunde KOlasveengen TMSkare CEriksen MStrand-Amundsen RJTonnessen TISkulberg VMfalseCerebral perfusion and metabolism with mild hypercapnia vs. normocapnia in a porcine post cardiac arrest model with and without targeted temperature management.<h4>Aim</h4>To determine whether targeting mild hypercapnia (PaCO₂ 7 kPa) would yield improved cerebral blood flow and metabolism compared to normocapnia (PaCO₂ 5 kPa) with and without targeted temperature management to 33 °C (TTM33) in a porcine post-cardiac arrest model.<h4>Methods</h4>39 pigs were resuscitated after 10 minutes of cardiac arrest using cardiopulmonary bypass and randomised to TTM33 or no-TTM, and hypercapnia or normocapnia. TTM33 was managed with intravasal cooling. Animals were stabilized for 30 minutes followed by a two-hour intervention period. Hemodynamic parameters were measured continuously, and neuromonitoring included intracranial pressure (ICP), pressure reactivity index, cerebral blood flow, brain-tissue pCO₂ and microdialysis. Measurements are reported as proportion of baseline, and areas under the curve during the 120 min intervention period were compared.<h4>Results</h4>Hypercapnia increased cerebral flow in both TTM33 and no-TTM groups, but also increased ICP (199% vs. 183% of baseline, <i>p</i> = 0.018) and reduced cerebral perfusion pressure (70% vs. 84% of baseline, <i>p</i> < 0.001) in no-TTM animals. Cerebral lactate (196% vs. 297% of baseline, <i>p</i> < 0.001), pyruvate (118% vs. 152% of baseline, <i>p</i> < 0.001), glycerol and lactate/pyruvate ratios were lower with hypercapnia in the TTM33 group, but only pyruvate (133% vs. 150% of baseline, <i>p</i> = 0.002) was lower with hypercapnia among no-TTM animals.<h4>Conclusion</h4>In this porcine post-arrest model, hypercapnia led to increased cerebral flow both with and without hypothermia, but also increased ICP and reduced cerebral perfusion pressure in no-TTM animals. The effects of hypercapnia were different with and without TTM.(Institutional protocol number: FOTS, id 14931).2024-01-01T00:00:00Z2024 Jun2025-04-04T20:07:03.569Z2025-04-04T20:07:03.569ZS-EPMC109507993851037610.1016/j.resplu.2024.100604