J Extra Corpor Technol 2023 , 55 , 167 – 174 Ó The Author ( s ), published by EDP Sciences , 2023 https :// doi . org / 10.1051 / ject / 2023028
Available online at : ject . edpsciences . org
ORIGINAL ARTICLE
Development of new colloid osmotic pressure measurement method using ultrafiltration membrane during cardiopulmonary bypass
Takeshi Matsumoto ( BSc ) 1 , 2 , * , Kiyoshi Yoshida 3 , Tomotaka Shinohara ( MSc ) 1 , 2 , Eiji Miyoshi ( PhD ) 1 , and Takayoshi Ueno ( PhD ) 2
1 Department of Functional Diagnostic Science , Division of Health Sciences , Osaka University Graduate School of Medicine , 1 – 7 , Suita-shi , Osaka-fu 565-0871 , Japan 2 Department of Nursing Practice Development , Division of Nursing Science , Osaka University Graduate School of Medicine ,
1 – 7 , Suita-shi , Osaka-fu 565-0871 , Japan 3 Department of Future Medical therapy , Division of Health Sciences , Osaka University , Graduate School of Medicine ,
1 – 7 , Suita-shi , Osaka-fu 565-0871 , Japan Received 19 April 2023 , Accepted 7 July 2023
Abstract – Background : Clinical practice of measuring colloid osmotic pressure ( COP ) was abandoned after correcting hypoosmolarity did not improve overall patient outcomes . However , the use of albumin and colloidal solutions has contributed to maintaining intraoperative and postoperative fluid balance at lower levels . Reduced perioperative fluid balance is consistently reported to have positive effects on clinical outcomes . Priming solutions for cardiopulmonary bypass typically include colloids ; however , the optimal type of priming solution has not yet been determined . Stricter COP management may further improve postoperative courses . To achieve this , the widespread adoption of a measurement method suitable for COP monitoring during cardiopulmonary bypass is required . Methods : A test circuit was made which measured COP using an ultrafiltration membrane method based on the changes in hydrostatic pressure that occurs across a semipermeable membrane . We then compared the measurements obtained using this method with colloidal osmometer measurements . Results : COP measurements were obtained for a total of 100 tests ( 10 times each for 10 test solutions ). The evaluation parameters included simultaneous reproducibility , correlation with the colloid osmometer , and measurement time . The results demonstrated high accuracy of the ultrafiltration membrane method , simultaneous reproducibility within 3 %, a high positive correlation with the colloid osmometer ( correlation coefficient : R 2 = 0.99 ; p < 0.01 ), and equal time required for measurement . Conclusion : Measuring COP using ultrafiltration membranes solves problems within existing measurement methods . Although further improvements in the method are necessary , it has implications for future research and clinical applications .
Key words : Ultrafiltration , Filter , Hemoconcentrator , Edema .
Introduction
Colloid osmotic pressure ( COP ) is generated primarily by serum albumin in the human body . Cardiopulmonary bypass used during open-heart surgeries lowers COP due to crystalloid hemodilution [ 1 ]. The clinical practice of measuring COP was abandoned , as correcting for hypoosmolarity did not improve patient outcomes [ 2 – 5 ]. The use of albumin and colloid solutions in heart surgery did not affect the risk of postoperative adverse events compared with patients for whom crystalloids were used . However , the use of albumin and colloidal solutions has contributed to maintaining perioperative and postoperative
* Corresponding author : me2014 @ hosp . med . osaka-u . ac . jp fluid balance at lower levels [ 6 , 7 ]. Reduced perioperative fluid balance is consistently reported to have positive effects on clinical outcomes ( clinical outcome score , duration of hospital stay , and increase in body weight ) [ 8 – 10 ]. In case we expect these secondary effects , the use of albumin and colloids is supported .
During cardiopulmonary bypass , COP decreases when the priming solution does not contain colloids [ 9 ]. Therefore , priming solutions typically contain colloids . However , the optimal type of priming solution has not yet been determined . Similar to the selection of a substitution fluid for blood loss during cardiopulmonary bypass , no clear parameters exist for selecting a colloid .
COP is correlated with fluid balance and could serve as a reliable parameter for colloid use . Low COP increases edema ,
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