Premium
Use of near‐infrared spectroscopy to identify trends in regional cerebral oxygen saturation in horses
Author(s) -
McConnell E. J.,
Rioja E.,
Bester L.,
Sanz M. G.,
Fosgate G. T.,
Saulez M. N.
Publication year - 2013
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/evj.12001
Subject(s) - anesthesia , medicine , oxygen saturation , correlation coefficient , oxygen , chemistry , mathematics , statistics , organic chemistry
Summary Reasons for performing study Alterations in cerebral haemodynamics may contribute to perianaesthetic complications in horses. Near‐infrared spectroscopy ( NIRS ) is frequently used intraoperatively in man to provide information regarding cerebral perfusion. Objectives To determine whether NIRS can identify trends in regional cerebral oxygen saturation ( rSO 2 ) in horses and whether there is a correlation between rSO 2 and venous oxygen tensions. Methods A cerebral oximeter sensor recorded rSO 2 from the dorsal sagittal sinus of 6 healthy horses. Values for rSO 2 , arterial and venous oxygen and carbon dioxide tensions ( PaO 2 , PvO 2 , P a CO 2 and PvCO 2 respectively), along with arteriovenous oxygen saturations ( SavO 2 ) were recorded in unsedated (recording period [ RP ] 1), sedated ( RP 2) and anaesthetised horses ( RP 3–5) and during recovery ( RP 6–8). During anaesthesia, horses were ventilated to achieve states of normo‐ ( RP 3), hyper‐ ( RP 4) and hypocapnoea ( RP 5). Data were evaluated descriptively and analysed using linear mixed‐effects models and P earson's correlation coefficient. Results Overall mean ± s.d. values for rSO 2 , PaO 2 , PvO 2 , PaCO 2 , SavO 2 and mean arterial pressure varied significantly by RP (P<0.001). Significant decreases in rSO 2 were identified between RP 1 and the post anaesthetic periods (P<0.001). No significant differences in rSO 2 values were identified between RP 1 and the intra‐anaesthesia periods or between RP 3, RP 4 and RP 5. Significant correlations were identified between rSO 2 and PaO 2 (r = 0.448, P<0.001), rSO 2 and PvO 2 (r = 0.512, P<0.001) and rSO 2 and S av O 2 (r = 0.469, P<0.001). Conclusions This is the first study to identify trends in rSO 2 in horses using NIRS . A positive correlation was identified between rSO 2 and PvO 2 , suggesting that alterations in cerebral oxygenation may be reflected in PvO 2 . Potential relevance Near‐infrared spectroscopy may be used to monitor trends in rSO 2 during equine anaesthesia. Decreasing rSO 2 values may act as an early warning signal, alerting clinicians to potential cerebral desaturation events and indicating a need for intervention.