Cerebral tissue oxygen saturation during therapeutic hypothermia in post-cardiac arrest patients

• Published in: Resuscitation 2013-06, Vol.84 (6), p.788-793
• Main Authors: Meex, Ingrid, Dens, Jo, Jans, Frank, Boer, Willem, Vanhengel, Kristof, Vundelinckx, Guy, Heylen, René, De Deyne, Cathy
• Format: Article
• Language: English
• Subjects: Aged; Carbon Dioxide - metabolism; Cardiac arrest; Cerebral tissue oxygen saturation; Cerebrovascular Circulation - physiology; Coma - physiopathology; Coma - therapy; Emergency; Female; Humans; Hypothermia, Induced - methods; Male; Middle Aged; Near infrared spectroscopy; Out-of-Hospital Cardiac Arrest - physiopathology; Out-of-Hospital Cardiac Arrest - therapy; Oxygen - metabolism; Prospective Studies; Spectroscopy, Near-Infrared; Therapeutic hypothermia
• ISSN: 0300-9572; 1873-1570
• DOI: 10.1016/j.resuscitation.2013.01.003

Abstract Aim of the study This observational study was performed to assess the cerebral tissue oxygen saturation during and after therapeutic hypothermia in comatose patients after out-of-hospital cardiac arrest. Methods We performed a prospective observational study on the cerebral tissue oxygen saturation (SctO2 ) in post-cardiac arrest patients treated with therapeutic hypothermia (TH) between March 2011 and April 2012. SctO2 (measured by near-infrared spectroscopy) was non-invasively and continuously measured in 28 post-cardiac arrest patients during hypothermia and active rewarming. Results At the start of mechanically induced TH, SctO2 was 68% (65–72) and PaCO2 was 47.2 mmHg (36.9 – 51.4). SctO2 and PaCO2 significantly decreased to 59% (57–64; p = 0.006) and 36.6 mmHg (33.9–44.7; p = 0.002), respectively, within the first 3 h of mechanically induced TH. Cerebral tissue oxygen saturation was significantly lower in non-survivors ( n = 10) compared with survivors ( n = 18) at 3 h after induction of hypothermia ( p = 0.02) while the decrease in PaCO2 was similar in both groups. During TH maintenance, SctO2 gradually returned to baseline values (69% (63–72)) at 24 h, with no differences between survivors and non-survivors ( p = 0.65). Carbon dioxide remained within the range of mild hypocapnia (32–38 mmHg) throughout the hypothermic period. During rewarming, SctO2 further increased to 71% (67–78). Conclusions Induction of TH in comatose post-CA patients changes the balance between oxygen delivery and supply. The decrease in SctO2 was less pronounced in patients surviving to hospital discharge.