Document Detail

Influence of hyperventilation on brain tissue-PO2, PCO2, and pH in patients with intracranial hypertension.
MedLine Citation:
PMID:  9779146     Owner:  NLM     Status:  MEDLINE    
A harmful effect of prolonged hyperventilation on outcome has been shown in comatose patients after severe head injury. The purpose of this study was to assess the acute effect of moderate hyperventilation for treatment of intracranial hypertension (ICP < 20 mmHg) on invasively measured brain tissue-PO2 (PtiO2), PCO2 (PtiCO2) and pH (tipH) in severely head injured patients. 15 severely head injured patients (GCS < or = 8) were prospectively studied. Intracranial pressure (ICP), mean arterial blood pressure (MABP), cerebral perfusion pressure (CPP), endtidal CO2 (ETCO2), PtiO2, PtiCO2 and tipH (Paratrend or Licox microsensors) were continuously recorded using multimodal monitoring. Following a baseline period of 15 minutes, patients were hyperventilated for 10 minutes. Arterial blood gas analysis was done before, during and after hyperventilation. At least three hyperventilation maneuvers were performed per patient. For statistical analysis the Friedman test was used. Hyperventilation (paCO2: 32.4 +/- 0.6 to 27.7 +/- 0.5 mmHg) significantly reduced ICP from 25.3 +/- 1.5 to 14.2 +/- 1.9 mmHg (p < 0.01). As a consequence, CPP increased by 9.6 +/- 3.4 mmHg to 76.8 +/- 3.2 mmHg. Brain tissue PCO2 decreased from 37.5 +/- 1.3 to 34.6 +/- 1.2 while tipH increased from 7.13 to 7.16. In all patients, hyperventilation led to a reduction of brain tissue PO2 (PtiO2/Licox: 24.6 +/- 1.4 to 21.9 +/- 1.7 mmHg, n.s.; PtiO2/Paratrend: 35.8 +/- 4.3 to 31.9 +/- 4.0 mmHg, n.s.). In one case hyperventilation even had to be stopped after 7 min because the drop in brain tissue PO2 below 10 mmHg signalized imminent hypoxia. As well known, hyperventilation improves CPP due to a reduction in ICP. However, this does not ameliorate cerebral oxygenation as demonstrated by the decrease in PtiO2. This underlines that hyperventilation should only be used with caution in the treatment of intracranial hypertension.
G H Schneider; A S Sarrafzadeh; K L Kiening; T F Bardt; A W Unterberg; W R Lanksch
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Acta neurochirurgica. Supplement     Volume:  71     ISSN:  0065-1419     ISO Abbreviation:  Acta Neurochir. Suppl.     Publication Date:  1998  
Date Detail:
Created Date:  1999-01-14     Completed Date:  1999-01-14     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  100962752     Medline TA:  Acta Neurochir Suppl     Country:  AUSTRIA    
Other Details:
Languages:  eng     Pagination:  62-5     Citation Subset:  IM    
Department of Neurosurgery, Rudolf Virchow Medical Center, Humboldt University, Berlin, Federal Republic of Germany.
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MeSH Terms
Acid-Base Equilibrium / physiology*
Blood Pressure / physiology
Blood Volume / physiology
Brain / blood supply*
Brain Injuries / physiopathology,  therapy*
Carbon Dioxide / blood*
Intracranial Hypertension / physiopathology,  therapy*
Middle Aged
Monitoring, Physiologic / instrumentation
Oxygen / blood*
Oxygen Consumption / physiology
Oxygen Inhalation Therapy*
Vasoconstriction / physiology
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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