Teodor Svedung Wettervik1, Timothy Howells2, Lars Hillered2, Pelle Nilsson2, Henrik Engquist3, Anders Lewén2, Per Enblad2, Elham Rostami2. 1. Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala, Sweden. Electronic address: teodor.svedung-wettervik@neuro.uu.se. 2. Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala, Sweden. 3. Department of Surgical Sciences/Anesthesia and Intensive Care, Uppsala University, Uppsala, Sweden.
Abstract
OBJECTIVE: Hyperventilation is a controversial treatment in traumatic brain injury (TBI). Prophylactic severe hyperventilation (below 3.3 kPa/25 mm Hg) is generally avoided, due to the risk of cerebral ischemia. Mild hyperventilation (arterial pCO2 within 4.0-4.5 kPa/30-34 mm Hg) in cases of intracranial hypertension is commonly used, but its safety and benefits are not fully elucidated. The aim of this study was to evaluate the use of mild hyperventilation and its relation to cerebral energy metabolism, pressure autoregulation, and clinical outcome in TBI. METHODS: This retrospective study was based on 120 patients with severe TBI treated at the neurointensive care unit, Uppsala University Hospital, Sweden, between 2008 and 2018. Data from cerebral microdialysis (glucose, pyruvate, and lactate), arterial pCO2, and pressure reactivity index were analyzed for the first 3 days post-injury. RESULTS: Mild hyperventilation, 4.0-4.5 kPa (30-34 mm Hg), was more frequently used early and the patients were gradually normoventilated. Low pCO2 was associated with slightly higher intracranial pressure and slightly lower cerebral perfusion pressure (P < 0.01). There was no univariate correlation between low pCO2 and worse cerebral energy metabolism. Multiple linear regression analysis showed that mild hyperventilation was associated with lower pressure reactivity index on day 2 (P = 0.03), suggesting better pressure autoregulation. Younger age and lower intracranial pressure were also associated with lower pressure reactivity index. CONCLUSIONS: These findings support the notion that mild hyperventilation is safe and may improve cerebrovascular reactivity.
OBJECTIVE:Hyperventilation is a controversial treatment in traumatic brain injury (TBI). Prophylactic severe hyperventilation (below 3.3 kPa/25 mm Hg) is generally avoided, due to the risk of cerebral ischemia. Mild hyperventilation (arterial pCO2 within 4.0-4.5 kPa/30-34 mm Hg) in cases of intracranial hypertension is commonly used, but its safety and benefits are not fully elucidated. The aim of this study was to evaluate the use of mild hyperventilation and its relation to cerebral energy metabolism, pressure autoregulation, and clinical outcome in TBI. METHODS: This retrospective study was based on 120 patients with severe TBI treated at the neurointensive care unit, Uppsala University Hospital, Sweden, between 2008 and 2018. Data from cerebral microdialysis (glucose, pyruvate, and lactate), arterial pCO2, and pressure reactivity index were analyzed for the first 3 days post-injury. RESULTS: Mild hyperventilation, 4.0-4.5 kPa (30-34 mm Hg), was more frequently used early and the patients were gradually normoventilated. Low pCO2 was associated with slightly higher intracranial pressure and slightly lower cerebral perfusion pressure (P < 0.01). There was no univariate correlation between low pCO2 and worse cerebral energy metabolism. Multiple linear regression analysis showed that mild hyperventilation was associated with lower pressure reactivity index on day 2 (P = 0.03), suggesting better pressure autoregulation. Younger age and lower intracranial pressure were also associated with lower pressure reactivity index. CONCLUSIONS: These findings support the notion that mild hyperventilation is safe and may improve cerebrovascular reactivity.
Authors: Alex O Trofimov; Darya I Agarkova; Arthem A Kopylov; Anton Dubrovin; Kseniia A Trofimova; Anatoly Sheludyakov; Dmitry Martynov; Peter N Cheremuhin; Denis E Bragin Journal: Adv Exp Med Biol Date: 2021 Impact factor: 3.650
Authors: Teodor Svedung Wettervik; Henrik Engquist; Timothy Howells; Samuel Lenell; Elham Rostami; Lars Hillered; Per Enblad; Anders Lewén Journal: J Intensive Care Med Date: 2020-07-27 Impact factor: 3.510
Authors: Teodor Svedung Wettervik; Anders Hånell; Timothy Howells; Elisabeth Ronne-Engström; Per Enblad; Anders Lewén Journal: J Intensive Care Med Date: 2022-02-16 Impact factor: 2.889