Perfusion
http://prf.sagepub.com/
The impact of haemodilution and bypass pump flow on cerebral oxygen desaturation during cardiopulmonary bypass - A comparison of two systems of cardiopulmonary bypass MJ Bennett, M Weatherall, G Webb, SF Dudnikov and CT Lloyd Perfusion published online 20 August 2014 DOI: 10.1177/0267659114548256 The online version of this article can be found at: http://prf.sagepub.com/content/early/2014/08/20/0267659114548256
Published by: http://www.sagepublications.com
Additional services and information for Perfusion can be found at: Email Alerts: http://prf.sagepub.com/cgi/alerts Subscriptions: http://prf.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> OnlineFirst Version of Record - Aug 20, 2014 What is This?
Downloaded from prf.sagepub.com at UCSF LIBRARY & CKM on November 21, 2014
548256 research-article2014
PRF0010.1177/0267659114548256PerfusionBennett et al.
Original paper
The impact of haemodilution and bypass pump flow on cerebral oxygen desaturation during cardiopulmonary bypass - A comparison of two systems of cardiopulmonary bypass.
Perfusion 1–6 © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0267659114548256 prf.sagepub.com
MJ Bennett,1 M Weatherall,2 G Webb,2 SF Dudnikov1 and CT Lloyd3
Abstract Objective: To determine the influence of haemodilution, bypass flow rates and calculated oxygen delivery during cardiopulmonary bypass (CPB) with either a conventional CPB (C-CPB) circuit or a miniaturised (Mini-CPB) circuit on cerebral oxygen desaturation. The effect of minimal haemodilution with a Mini-CPB was investigated. Participants: Eighty patients scheduled for elective cardiac surgery. Intervention: Oxygenated haemoglobin (O2Hb) and tissue oxygenation index (TOI) were measured with near-infrared spectroscopy (NIRS). Results: The average indexed bypass pump flow was significantly lower with Mini-CPB. When combined with haemoglobin concentration, the average oxygen delivery was the same between groups. Patients in the C-CPB group had a greater duration and severity of cerebral desaturation to a level 400s was achieved with heparin 300 IU. kg−1. The final cardioplegia concentrations were the same (K+ 20 mmol.l−1 induction and 10 mmol.l−1 maintenance). In the Mini-CPB group, retrograde autologous priming of the circuit was undertaken over ⩽1 min prior to the commencement of bypass. The target haematocrit (Hct) during bypass was maintained at 21% or higher, with red blood cell transfusion given as necessary.
Near-infrared spectroscopy Near-infrared spectroscopy (NIRS) using the NIRO200NX monitored changes in oxygenated haemoglobin (O2Hb) and tissue oxygenation index (TOI). Before the induction of anesthesia and with the patient breathing 2-4 l.min−1 oxygen, near-infrared light-transmitting optodes and light detectors were placed on each frontotemporal region, avoiding the frontal sinuses. Monitoring started 10 minutes before the induction of anaesthesia (Baseline) and continued until skin closure. Data were recorded at 1 Hz. Chromophore concentration changes (change in O2Hb and HHb (deoxygenated)) were measured in micromoles per litre. Cerebral saturation, as expressed by the TOI%, is the ratio of oxygenated to total tissue haemoglobin and was measured in percentages of oxygen saturation of haemoglobin. After data collection, analysis was undertaken to record the degree of cerebral desaturation (average from right and left cerebral hemispheres) below absolute TOI% values of 50% and 65% and below a value of 20% less than baseline values. Each was recorded as the product of depth and duration of desaturation (%.seconds).
Downloaded from prf.sagepub.com at UCSF LIBRARY & CKM on November 21, 2014
3
Bennett et al. Table 1. Patient demographics, operation type and intraoperative variables. Variable
Mini-CPB
C-CPB
Statistics
(n = 39)
(n = 41)
p (95% CI (Mini-CPB – C-CPB))
Age (yrs) Body surface area (m2) Logistic EuroScore History of diabetes mellitus History of hypertension History of peripheral vascular disease Operation: CABG AVR CABG/AVR Other
74.2 ± 7.2 1.92 ± 0.21 9.06 ± 9.58 6 (15.4%) 34 (87.2%) 0
65.3 ± 9.6 2.01 ± 0.27 5.83+/–8.35 7 (17.1%) 30 (73.2%) 4 (5.8%)
p
http://prf.sagepub.com/
The impact of haemodilution and bypass pump flow on cerebral oxygen desaturation during cardiopulmonary bypass - A comparison of two systems of cardiopulmonary bypass MJ Bennett, M Weatherall, G Webb, SF Dudnikov and CT Lloyd Perfusion published online 20 August 2014 DOI: 10.1177/0267659114548256 The online version of this article can be found at: http://prf.sagepub.com/content/early/2014/08/20/0267659114548256
Published by: http://www.sagepublications.com
Additional services and information for Perfusion can be found at: Email Alerts: http://prf.sagepub.com/cgi/alerts Subscriptions: http://prf.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> OnlineFirst Version of Record - Aug 20, 2014 What is This?
Downloaded from prf.sagepub.com at UCSF LIBRARY & CKM on November 21, 2014
548256 research-article2014
PRF0010.1177/0267659114548256PerfusionBennett et al.
Original paper
The impact of haemodilution and bypass pump flow on cerebral oxygen desaturation during cardiopulmonary bypass - A comparison of two systems of cardiopulmonary bypass.
Perfusion 1–6 © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0267659114548256 prf.sagepub.com
MJ Bennett,1 M Weatherall,2 G Webb,2 SF Dudnikov1 and CT Lloyd3
Abstract Objective: To determine the influence of haemodilution, bypass flow rates and calculated oxygen delivery during cardiopulmonary bypass (CPB) with either a conventional CPB (C-CPB) circuit or a miniaturised (Mini-CPB) circuit on cerebral oxygen desaturation. The effect of minimal haemodilution with a Mini-CPB was investigated. Participants: Eighty patients scheduled for elective cardiac surgery. Intervention: Oxygenated haemoglobin (O2Hb) and tissue oxygenation index (TOI) were measured with near-infrared spectroscopy (NIRS). Results: The average indexed bypass pump flow was significantly lower with Mini-CPB. When combined with haemoglobin concentration, the average oxygen delivery was the same between groups. Patients in the C-CPB group had a greater duration and severity of cerebral desaturation to a level 400s was achieved with heparin 300 IU. kg−1. The final cardioplegia concentrations were the same (K+ 20 mmol.l−1 induction and 10 mmol.l−1 maintenance). In the Mini-CPB group, retrograde autologous priming of the circuit was undertaken over ⩽1 min prior to the commencement of bypass. The target haematocrit (Hct) during bypass was maintained at 21% or higher, with red blood cell transfusion given as necessary.
Near-infrared spectroscopy Near-infrared spectroscopy (NIRS) using the NIRO200NX monitored changes in oxygenated haemoglobin (O2Hb) and tissue oxygenation index (TOI). Before the induction of anesthesia and with the patient breathing 2-4 l.min−1 oxygen, near-infrared light-transmitting optodes and light detectors were placed on each frontotemporal region, avoiding the frontal sinuses. Monitoring started 10 minutes before the induction of anaesthesia (Baseline) and continued until skin closure. Data were recorded at 1 Hz. Chromophore concentration changes (change in O2Hb and HHb (deoxygenated)) were measured in micromoles per litre. Cerebral saturation, as expressed by the TOI%, is the ratio of oxygenated to total tissue haemoglobin and was measured in percentages of oxygen saturation of haemoglobin. After data collection, analysis was undertaken to record the degree of cerebral desaturation (average from right and left cerebral hemispheres) below absolute TOI% values of 50% and 65% and below a value of 20% less than baseline values. Each was recorded as the product of depth and duration of desaturation (%.seconds).
Downloaded from prf.sagepub.com at UCSF LIBRARY & CKM on November 21, 2014
3
Bennett et al. Table 1. Patient demographics, operation type and intraoperative variables. Variable
Mini-CPB
C-CPB
Statistics
(n = 39)
(n = 41)
p (95% CI (Mini-CPB – C-CPB))
Age (yrs) Body surface area (m2) Logistic EuroScore History of diabetes mellitus History of hypertension History of peripheral vascular disease Operation: CABG AVR CABG/AVR Other
74.2 ± 7.2 1.92 ± 0.21 9.06 ± 9.58 6 (15.4%) 34 (87.2%) 0
65.3 ± 9.6 2.01 ± 0.27 5.83+/–8.35 7 (17.1%) 30 (73.2%) 4 (5.8%)
p
