HPE Human albumin handbook | Page 30

Choice of fluid resuscitation after cardiac surgery

Sound management of perioperative fluid resuscitation in cardiac surgery helps to reduce postoperative bleeding , prevent fluid overload , kidney impairment and systemic inflammation .
Haitao Zhang MD Fangfang Cao Fuwai Hospital , Chinese Academy of Medicine , China
In cardiac surgery , adequate fluid resuscitation following the procedure is the most important haemodynamic intervention . As a first-line action , the main objectives of fluid management are to provide sufficient cardiac output and tissue perfusion .
The further aims of fluid management in this patient population include : ( 1 ) managing blood loss during surgery ; ( 2 ) blood vessel volume expansion after rewarming ; ( 3 ) managing extracorporeal circulation-related inflammation leading to fluid loss into the third space ; ( 4 ) and reducing transient ischaemic reperfusion injury of the heart , myocardial stunning and decreased ventricular compliance , which increase the need for cardiac preload .
Selection of fluid after cardiac surgery Crystalloids or colloids ? Crystalloids can freely permeate the blood vessels . Approximately 75 – 80 % of crystalloids are distributed to the tissue space , whereas 20 – 25 % persists in the blood vessels . The average time of intravascular persistence is short ( 45 minutes ). When fluid input is large enough , it will result in dilution of serum albumin and reduction of blood osmotic pressure , which further lead to interstitial oedema , pulmonary oedema , and dilution of blood coagulation factors .
Colloids do not permeate blood vessels . However , if capillary leakage syndrome develops and proteins as well as large molecules leak out , colloids will lose the theoretical advantages mentioned above . To address uncertainty in the results of a Cochrane review and subsequent meta-analysis , the 2004 SAFE study in general ICU enrolled nearly 7000 patients in Australia and New Zealand and compared 4 % albumin versus normal saline to assess the safety of albumin . There were no observed differences in mortality , duration of stay in the ICU and mechanical ventilation time between albumin and saline . Guidelines on septic shock recommend crystalloids as the preferred fluid . 1 Cardiac surgeons generally follow the result of this study .
The goal of albumin infusion is to have a safe and efficacious colloid in patients with larger volume needs . Albumin is able to maintain circulation volume as effectively as five-times the volume of normal saline . One gram of albumin is able to retain 1ml of water ; 5g of albumin is equivalent to 100ml plasma or 200ml whole blood with regards to maintenance of plasma colloid osmotic pressure . The advantage is that its expansion capacity is significant and interstitial oedema is reduced . Artificial colloids are not superior to crystals . They affect coagulation function after cardiac surgery coagulation and are associated with renal failure . Therefore it is more suitable to use crystalloid + adequate natural colloid during the perioperative stage . 2
Artificial colloids or crystalloids ? In 2013 , a study of more than 6000 patients compared 6 % hydroxyethyl starch 130 / 0.4 ( n = 2137 ), 4 % gelatin ( n = 2324 ), and crystalloids ( n = 2017 ) in cardiac surgery . 3 The need for renal replacement therapy was significantly greater with HES than for crystalloids . The time to vasoactive drug withdrawal , and the return of blood lactate levels and mean arterial pressure to normal did not differ between the three groups . However , the amount of fluid intake in the crystalloid group increased during the first 20 hours ( 224ml / kg ). 3
Another study compared the resuscitation effects of artificial colloid vs saline . The saline group had a significantly increased vasoactive drug volume , increased pulmonary oedema , and an increased need for cardiac pacing , whereas the artificial colloid group required increased plasma transfusion . 4 Therefore , the application of artificial colloids after cardiac surgery has a higher risk of renal replacement therapy and does not confer further advantages than crystalloids , but crystalloids significantly increase the amount of infusion .
In 2013 , a study compared more than 6000 cardiac surgery patients who were enrolled into three groups : 6 % hydroxyethyl starch 130 / 0.4 ( n = 2137 ), 4 % gelatin ( n = 2324 ), and crystalloid ( n = 2017 ). Significantly more cases required renal replacement treatment in the gelatin and hydroxyethyl starch groups than the crystalloid group . The time of withdrawing vasoactive drugs , normalisation of blood lactate levels , and mean arterial pressure were not different among the three groups . However , the amount of fluid input in the crystal group increased during the first 20 hours by 224ml / kg . 3 Another study compared the resuscitation effects of artificial colloid and saline . The saline group had a significantly increased need for vasoactive drugs , more severe pulmonary oedema , and increased the need for cardiac pacing . The artificial colloid group required more plasma transfusion . 4 Therefore , artificial colloids transfusion after cardiac surgery has a higher risk for receiving renal replacement therapy and does not show superiority to crystals . However with crystalloids , the amount of transfusion volume increases significantly .
Albumin or artificial colloids ? During extracorporeal circulation for cardiac surgery , inflammation and coagulation system are
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