Does the use of a centrifugal pump offer any additional benefit for patients having open heart surgery
http://www.100md.com
《血管的通路杂志》
a Department of Cardiothoracic Surgery, North Staffordshire Royal Infirmary, Stoke on Trent, UK
b Department of Cardiothoracic Surgery, James Cook University Hospital, Middlesbrough, UK
c Department of Cardiothoracic Surgery, Blackpool Victoria Hospital, UK
Abstract
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether a centrifugal pump is better than a roller pump in patients undergoing cardiac surgery. Altogether 93 papers were identified using the below mentioned search, of which 15 papers presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group, relevant outcomes and weaknesses were tabulated. We conclude that there is no evidence for the benefit of a centrifugal pump over a roller pump in elective coronary artery bypass grafting in respect of blood loss, clinical outcomes or neurological problems. The two largest studies, a large RCT of 1000 patients and a cohort study of 4000 patients, both demonstrated a halving in the incidence of neurological events with numbers needed to treat of 37 and 91. However, the remaining much smaller RCTs and cohort studies that we assessed failed to show significant differences in either clinical or biochemical markers.
Key Words: Evidence-based medicine; Thoracic surgery; Cardiopulmonary bypass; Centrifugal pump; Extracorporeal circulation; Roller pump
1. Introduction
A best evidence topic was constructed according to the structured protocol. This protocol is fully described in the ICVTS [1].
2. Clinical scenario
You are about to perform a Coronary arterial bypass graft on a 75-year-old gentleman with good LV function. You have recently been asking your perfusionist to use a centrifugal pump for all your high risk cases, and the perfusionist asks you if you want one for this case. You say ‘yes’ but you are unsure if there is evidence for benefit for these lower risk patients and, therefore, resolve to search for papers on the subject after the case.
3. Three-part question
In [patients undergoing cardiac surgery,] does [the use of a centrifugal pump] improve [post operative outcomes].
4. Search strategy
Medline 1966 to Oct 2004, Embase 1980 to Oct 2004 and CINAHL 1982 to Oct 2004 using the OVID interface. Extracorporeal Circulation/OR extracorporeal circulation.mp OR exp Heart-Lung Machine OR heart-lung machine.mp OR exp Heart assist devices/OR Heart-assist device.mp] AND [exp centrifugation/OR centrifugal pump$.mp OR vortex pump$.mp]. and [roller pump.mp OR roller head pump$.mp].
5. Search outcome
A total of 93 papers were identified of which 26 papers were either large cohort studies or randomised controlled trials in patients undergoing cardiac surgery, comparing roller pumps with centrifugal pumps. Fifteen papers were selected representing the best evidence for the topic References [2–16] (Table 1) and an additional 11 smaller studies were rejected [17–27].
6. Comments
Parolari et al. [3] performed a retrospective analysis of 4000 patients who underwent open-heart surgery either with a centrifugal pump or with a roller pump. (Results published again with fewer patients by Alamanni et al. [2]) The groups were not matched and the centrifugal pump was generally selected when a bypass time over 100 min was anticipated. A range of pre-operative variables such as TIA, MI, re-operation were also higher in the centrifugal pump group. There was no difference in hospital mortality between the groups but the centrifugal pump patients had a significantly lower permanent neurological deficit rate (1.5% vs. 2.6%). This halving of the stroke rate was despite a higher incidence of pre-op CVAs and longer bypass times in the centrifugal pump group.
Klein et al. [4,5] performed a prospective randomised trial of 1000 patients undergoing routine open heart surgery. They demonstrated significantly higher red blood cell counts, 30% less chest tube drainage, lower transfusion rates and significantly lower incidence of neurological events (5.2% vs. 2.4%) in the centrifugal pump group (NNT 100). Interestingly, there was no difference in the rate of haemolysis and also no mortality difference. This study was sponsored by the manufacturers of the centrifugal pump.
Scott et al. [6,7] randomised 113 elective coronary artery bypass patients and compared the effects of pump type on blood loss, transfusion requirements and also neuropsychometric testing. No difference in blood product usage, haemoglobin, platelet numbers and chest tube drainage were detected. In addition, no differences in neuropsychometric testing were found.
Driessen et al. [13] enrolled 50 elective patients undergoing coronary artery bypass grafting. They were unable to demonstrate any significant haemodynamic differences, or differences in ICU stay, Hb level or platelet count. However, they detected a need for greater amounts of sodium nitroprusside during cardiopulmonary bypass in the roller pump group.
Hansbro et al. [8] performed a randomised study in 60 patients, looking at standard roller pumps, non-occlusive roller pumps and centrifugal pumps. They found no increase in rates of haemolysis, haemoglobin levels, or white cell count after the study, although the numbers were small.
Ashraf et al. [9] studied 40 patients randomised to centrifugal pump or a non-occlusive roller pump. Blood loss and haemodynamics were recorded and there was no significant difference between the groups. In contrast to other studies, neutrophil count, IL-6, and elastase release were higher in the centrifugal pump group suggesting an increase in inflammatory response using the centrifugal pump. In a separate paper Ashraf [10] also measured S-100 Beta in these patients as a marker of brain injury but found no significant difference.
Andersen et al. [11] performed a PRCT in 34 patients, looking at the inflammatory effects of cardiopulmonary bypass with particular emphasis on platelet activation. No clinical differences were found and only a marginal increase in platelet aggregates were seen in the roller pump group. No differences in haemolysis, single platelets, or platelet fragments were seen.
Baufreton et al. [12] sought to demonstrate reduced inflammation with a centrifugal pump. In fact in a randomised study of 29 patients they showed a higher neutrophil and complement activation level in the centrifugal pump group. No other differences were shown, either clinically or in levels of interleukins or TNF.
Macey et al. [14] measured the levels of CD11b, Cd18, CD14, Cd64 and L selectin in 46 patients randomised to either roller or centrifugal pumps. All measured rises in inflammatory mediators were independent of pump type used.
Lindholm et al. [15] studied 2 groups of elderly patients randomised to either a closed system, heparin bonded circuit with a centrifugal pump or a standard circuit with a roller pump. They found significantly decreased levels of 3 out of 4 complement activation measures, IL-8, and Elastase on rewarming. However, there were no differences in TNF, IL-6, C4d, TAT, D-Dimer, or t-PA at any stage, and all markers were at similar levels by 24 h.
Mullen et al. [16] randomised 90 patients to roller pump, centrifugal pump with heparin circuit and either normal or low heparinization. They found no clinical differences in bleeding, transfusion requirements or clinical outcomes between groups.
7. Clinical bottom line
The two largest studies, a large RCT of 1000 patients and a cohort study of 4000 patients, both demonstrated a halving in the incidence of neurological events with numbers needed to treat of 37 and 91. However, the remaining much smaller RCTs and cohort studies that we assessed failed to show significant differences in either clinical or biochemical markers.
References
Dunning J, Prendergast B, Mackway-Jones K. Towards evidence-based medicine in cardiothoracic surgery: best BETS. Interactive CardioVasc Thorac Surg 2003; 2:405–409.
Alamanni F, Parolari A, Zanobini M, Porqueddu M, Dainese L, Bertera A, Costa C, Fusari M, Spirito R, Biglioli P. Centrifugal pump and reduction of neurological risk in adult cardiac surgery. J Extra Corporeal Technol 2001; 33:4–9.
Parolari A, Alamanni F, Naliato M, Spirito R, Franze V, Pompilio G, Agrifoglio M, Biglioli P. Adult cardiac surgery outcomes: role of the pump type. Eur J Cardiothorac Surg 2000; 18:575–582.
Klein M, Dauben HP, Schulte HD, Gams E. Centrifugal pumping during routine open heart surgery improves clinical outcome. Artif Organs 1998; 22:326–336.
M E, Mahoney CB, Probst C, Schulte HD, Gams E. Blood product use during routine open heart surgery: the impact of the centrifugal pump. Artif Organs 2001; 25:300–305.
Scott DA, Silbert BS, Doyle TJ, Blyth C, Borton MC, O'Brien JL, de LH. Centrifugal versus roller head pumps for cardiopulmonary bypass: effect on early neuropsychologic outcomes after coronary artery surgery. J Cardiothorac Vasc Anesth 2002; 16:715–722.
Scott DA, Silbert BS, Blyth C, O'Brien J, Santamaria J. Blood loss in elective coronary artery surgery: a comparison of centrifugal versus roller pump heads during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2001; 15:322–325.
Hansbro SD, Sharpe DA, Catchpole R, Welsh KR, Munsch CM, McGoldrick JP, Kay PH. Haemolysis during cardiopulmonary bypass: an in vivo comparison of standard roller pumps, nonocclusive roller pumps and centrifugal pumps. Perfusion 1999; 14:3–10.
Ashraf S, Butler J, Tian Y, Cowan D, Lintin S, Saunders NR, Watterson KG, Martin PG. Inflammatory mediators in adults undergoing cardiopulmonary bypass: comparison of centrifugal and roller pumps. Ann Thorac Surg 1998; 65:480–484.
Ashraf S, Bhattacharya K, Zacharias S, Kaul P, Kay PH, Watterson KG. Serum S100 beta release after coronary artery bypass grafting: roller versus centrifugal pump. Ann Thorac Surg 1998; 66:1958–1962.
Andersen KS, Nygreen EL, Grong K, Leirvaag B, Holmsen H. Comparison of the centrifugal and roller pump in elective coronary artery bypass surgery – a prospective, randomised study with special emphasis upon platelet activation. Scand Cardiovasc J 2003; 37:356–362.
Baufreton C, Intrator L, Jansen PG, te Velthuis H, Le Besnerais P, Vonk A, Farcet JP, Wildevuur CR, Loisance DY. Inflammatory response to cardiopulmonary bypass using roller or centrifugal pumps. Ann Thorac Surg 1999; 67:972–977.
Driessen JJ, Fransen G, Rondelez L, Schelstraete E, Gevaert L. Comparison of the standard roller pump and a pulsatile centrifugal pump for extracorporeal circulation during routine coronary artery bypass grafting. Perfusion 1991; 6:303–311.
Macey MG, McCarthy DA, Trivedi UR, Venn GE, Chambers DJ, Brown KA. Neutrophil adhesion molecule expression during cardiopulmonary bypass: a comparative study of roller and centrifugal pumps. Perfusion 1997; 12:293–301.
Lindholm L, Westerberg M, Bengtsson A, Ekroth R, Jensen E, Jeppsson A. A closed perfusion system with heparin coating and centrifugal pump improves cardiopulmonary bypass biocompatibility in elderly patients. Ann Thorac Surg 2004; 78:2131–2138.
Mullen JC, Bentley MJ, Gelfand ET, Koshal A, Modry DL, Guenther CR, Etches WS, Stang LJ, Lopushinsky SR. Coronary artery bypass surgery with heparin-coated perfusion circuits and low-dose heparinization. Can J Surg 2002; 45:166–172.
Babin-Ebell J, Misoph M, Mullges W, Neukam K, Elert O. Reduced release of tissue factor by application of a centrifugal pump during cardiopulmonary bypass. Heart Vessels 1998; 13:147–151.
Wheeldon DR, Bethune DW, Gill RD. Vortex pumping for routine cardiac surgery: a comparative study. Perfusion 1990; 5:135–143.
Zirbel GM, Letson ME, Kauffman JN, Walker CT, Guyton RA. Hematologic derangements of cardiopulmonary bypass: a comparison of two perfusion systems. J Extra Corporeal Technol 1990; 22:15–19.
Misoph M, Babin-Ebell J, Schwender S. A comparative evaluation of the effect of pump type and heparin-coated surfaces on platelets during cardiopulmonary bypass. Thorac Cardiovasc Surg 1997; 45:302–306.
Murakami F, Usui A, Hiroura M, Kawamura M, Koyama T, Murase M. Clinical study of totally roller pumpless cardiopulmonary bypass system. Artif Organs 1997; 21:803–807.
Moen O, Fosse E, Dregelid E, Brockmeier V, Andersson C, Hogasen K, Venge P, Mollnes TE, Kierulf P. Centrifugal pump and heparin coating improves cardiopulmonary bypass biocompatibility. Ann Thorac Surg 1996; 62:1134–1140.
Yoshikai M, Hamada M, Takarabe K, Okazaki Y, Ito T. Clinical use of centrifugal pumps and the roller pump in open heart surgery: a comparative evaluation. Artif Organs 1996; 20:704–706.
Perttila J, Salo M, Peltola O. Comparison of the effects of centrifugal versus roller pump on the immune response in open-heart surgery. Perfusion 1995; 10:249–256.
Steinbrueckner BE, Steigerwald U, Keller F, Neukam K, Elert O, Babin-Ebell J. Centrifugal and roller pumps – are there differences in coagulation and fibrinolysis during and after cardiopulmonary bypass. Heart Vessels 1995; 10:46–53.
Nishinaka T, Nishida H, Endo M, Miyagishima M, Ohtsuka G, Koyanagi H. Less blood damage in the impeller centrifugal pump: a comparative study with the roller pump in open heart surgery. Artif Organs 1996; 20:707–710.
Jakob HG, Hafner G, Thelemann C, Sturer A, Prellwitz W, Oelert H. Routine extracorporeal circulation with a centrifugal or roller pump. ASAIO Trans 1991; 37:M487–M489.(Julius Asante-Siaw, James)
b Department of Cardiothoracic Surgery, James Cook University Hospital, Middlesbrough, UK
c Department of Cardiothoracic Surgery, Blackpool Victoria Hospital, UK
Abstract
A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether a centrifugal pump is better than a roller pump in patients undergoing cardiac surgery. Altogether 93 papers were identified using the below mentioned search, of which 15 papers presented the best evidence to answer the clinical question. The author, journal, date and country of publication, patient group, relevant outcomes and weaknesses were tabulated. We conclude that there is no evidence for the benefit of a centrifugal pump over a roller pump in elective coronary artery bypass grafting in respect of blood loss, clinical outcomes or neurological problems. The two largest studies, a large RCT of 1000 patients and a cohort study of 4000 patients, both demonstrated a halving in the incidence of neurological events with numbers needed to treat of 37 and 91. However, the remaining much smaller RCTs and cohort studies that we assessed failed to show significant differences in either clinical or biochemical markers.
Key Words: Evidence-based medicine; Thoracic surgery; Cardiopulmonary bypass; Centrifugal pump; Extracorporeal circulation; Roller pump
1. Introduction
A best evidence topic was constructed according to the structured protocol. This protocol is fully described in the ICVTS [1].
2. Clinical scenario
You are about to perform a Coronary arterial bypass graft on a 75-year-old gentleman with good LV function. You have recently been asking your perfusionist to use a centrifugal pump for all your high risk cases, and the perfusionist asks you if you want one for this case. You say ‘yes’ but you are unsure if there is evidence for benefit for these lower risk patients and, therefore, resolve to search for papers on the subject after the case.
3. Three-part question
In [patients undergoing cardiac surgery,] does [the use of a centrifugal pump] improve [post operative outcomes].
4. Search strategy
Medline 1966 to Oct 2004, Embase 1980 to Oct 2004 and CINAHL 1982 to Oct 2004 using the OVID interface. Extracorporeal Circulation/OR extracorporeal circulation.mp OR exp Heart-Lung Machine OR heart-lung machine.mp OR exp Heart assist devices/OR Heart-assist device.mp] AND [exp centrifugation/OR centrifugal pump$.mp OR vortex pump$.mp]. and [roller pump.mp OR roller head pump$.mp].
5. Search outcome
A total of 93 papers were identified of which 26 papers were either large cohort studies or randomised controlled trials in patients undergoing cardiac surgery, comparing roller pumps with centrifugal pumps. Fifteen papers were selected representing the best evidence for the topic References [2–16] (Table 1) and an additional 11 smaller studies were rejected [17–27].
6. Comments
Parolari et al. [3] performed a retrospective analysis of 4000 patients who underwent open-heart surgery either with a centrifugal pump or with a roller pump. (Results published again with fewer patients by Alamanni et al. [2]) The groups were not matched and the centrifugal pump was generally selected when a bypass time over 100 min was anticipated. A range of pre-operative variables such as TIA, MI, re-operation were also higher in the centrifugal pump group. There was no difference in hospital mortality between the groups but the centrifugal pump patients had a significantly lower permanent neurological deficit rate (1.5% vs. 2.6%). This halving of the stroke rate was despite a higher incidence of pre-op CVAs and longer bypass times in the centrifugal pump group.
Klein et al. [4,5] performed a prospective randomised trial of 1000 patients undergoing routine open heart surgery. They demonstrated significantly higher red blood cell counts, 30% less chest tube drainage, lower transfusion rates and significantly lower incidence of neurological events (5.2% vs. 2.4%) in the centrifugal pump group (NNT 100). Interestingly, there was no difference in the rate of haemolysis and also no mortality difference. This study was sponsored by the manufacturers of the centrifugal pump.
Scott et al. [6,7] randomised 113 elective coronary artery bypass patients and compared the effects of pump type on blood loss, transfusion requirements and also neuropsychometric testing. No difference in blood product usage, haemoglobin, platelet numbers and chest tube drainage were detected. In addition, no differences in neuropsychometric testing were found.
Driessen et al. [13] enrolled 50 elective patients undergoing coronary artery bypass grafting. They were unable to demonstrate any significant haemodynamic differences, or differences in ICU stay, Hb level or platelet count. However, they detected a need for greater amounts of sodium nitroprusside during cardiopulmonary bypass in the roller pump group.
Hansbro et al. [8] performed a randomised study in 60 patients, looking at standard roller pumps, non-occlusive roller pumps and centrifugal pumps. They found no increase in rates of haemolysis, haemoglobin levels, or white cell count after the study, although the numbers were small.
Ashraf et al. [9] studied 40 patients randomised to centrifugal pump or a non-occlusive roller pump. Blood loss and haemodynamics were recorded and there was no significant difference between the groups. In contrast to other studies, neutrophil count, IL-6, and elastase release were higher in the centrifugal pump group suggesting an increase in inflammatory response using the centrifugal pump. In a separate paper Ashraf [10] also measured S-100 Beta in these patients as a marker of brain injury but found no significant difference.
Andersen et al. [11] performed a PRCT in 34 patients, looking at the inflammatory effects of cardiopulmonary bypass with particular emphasis on platelet activation. No clinical differences were found and only a marginal increase in platelet aggregates were seen in the roller pump group. No differences in haemolysis, single platelets, or platelet fragments were seen.
Baufreton et al. [12] sought to demonstrate reduced inflammation with a centrifugal pump. In fact in a randomised study of 29 patients they showed a higher neutrophil and complement activation level in the centrifugal pump group. No other differences were shown, either clinically or in levels of interleukins or TNF.
Macey et al. [14] measured the levels of CD11b, Cd18, CD14, Cd64 and L selectin in 46 patients randomised to either roller or centrifugal pumps. All measured rises in inflammatory mediators were independent of pump type used.
Lindholm et al. [15] studied 2 groups of elderly patients randomised to either a closed system, heparin bonded circuit with a centrifugal pump or a standard circuit with a roller pump. They found significantly decreased levels of 3 out of 4 complement activation measures, IL-8, and Elastase on rewarming. However, there were no differences in TNF, IL-6, C4d, TAT, D-Dimer, or t-PA at any stage, and all markers were at similar levels by 24 h.
Mullen et al. [16] randomised 90 patients to roller pump, centrifugal pump with heparin circuit and either normal or low heparinization. They found no clinical differences in bleeding, transfusion requirements or clinical outcomes between groups.
7. Clinical bottom line
The two largest studies, a large RCT of 1000 patients and a cohort study of 4000 patients, both demonstrated a halving in the incidence of neurological events with numbers needed to treat of 37 and 91. However, the remaining much smaller RCTs and cohort studies that we assessed failed to show significant differences in either clinical or biochemical markers.
References
Dunning J, Prendergast B, Mackway-Jones K. Towards evidence-based medicine in cardiothoracic surgery: best BETS. Interactive CardioVasc Thorac Surg 2003; 2:405–409.
Alamanni F, Parolari A, Zanobini M, Porqueddu M, Dainese L, Bertera A, Costa C, Fusari M, Spirito R, Biglioli P. Centrifugal pump and reduction of neurological risk in adult cardiac surgery. J Extra Corporeal Technol 2001; 33:4–9.
Parolari A, Alamanni F, Naliato M, Spirito R, Franze V, Pompilio G, Agrifoglio M, Biglioli P. Adult cardiac surgery outcomes: role of the pump type. Eur J Cardiothorac Surg 2000; 18:575–582.
Klein M, Dauben HP, Schulte HD, Gams E. Centrifugal pumping during routine open heart surgery improves clinical outcome. Artif Organs 1998; 22:326–336.
M E, Mahoney CB, Probst C, Schulte HD, Gams E. Blood product use during routine open heart surgery: the impact of the centrifugal pump. Artif Organs 2001; 25:300–305.
Scott DA, Silbert BS, Doyle TJ, Blyth C, Borton MC, O'Brien JL, de LH. Centrifugal versus roller head pumps for cardiopulmonary bypass: effect on early neuropsychologic outcomes after coronary artery surgery. J Cardiothorac Vasc Anesth 2002; 16:715–722.
Scott DA, Silbert BS, Blyth C, O'Brien J, Santamaria J. Blood loss in elective coronary artery surgery: a comparison of centrifugal versus roller pump heads during cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2001; 15:322–325.
Hansbro SD, Sharpe DA, Catchpole R, Welsh KR, Munsch CM, McGoldrick JP, Kay PH. Haemolysis during cardiopulmonary bypass: an in vivo comparison of standard roller pumps, nonocclusive roller pumps and centrifugal pumps. Perfusion 1999; 14:3–10.
Ashraf S, Butler J, Tian Y, Cowan D, Lintin S, Saunders NR, Watterson KG, Martin PG. Inflammatory mediators in adults undergoing cardiopulmonary bypass: comparison of centrifugal and roller pumps. Ann Thorac Surg 1998; 65:480–484.
Ashraf S, Bhattacharya K, Zacharias S, Kaul P, Kay PH, Watterson KG. Serum S100 beta release after coronary artery bypass grafting: roller versus centrifugal pump. Ann Thorac Surg 1998; 66:1958–1962.
Andersen KS, Nygreen EL, Grong K, Leirvaag B, Holmsen H. Comparison of the centrifugal and roller pump in elective coronary artery bypass surgery – a prospective, randomised study with special emphasis upon platelet activation. Scand Cardiovasc J 2003; 37:356–362.
Baufreton C, Intrator L, Jansen PG, te Velthuis H, Le Besnerais P, Vonk A, Farcet JP, Wildevuur CR, Loisance DY. Inflammatory response to cardiopulmonary bypass using roller or centrifugal pumps. Ann Thorac Surg 1999; 67:972–977.
Driessen JJ, Fransen G, Rondelez L, Schelstraete E, Gevaert L. Comparison of the standard roller pump and a pulsatile centrifugal pump for extracorporeal circulation during routine coronary artery bypass grafting. Perfusion 1991; 6:303–311.
Macey MG, McCarthy DA, Trivedi UR, Venn GE, Chambers DJ, Brown KA. Neutrophil adhesion molecule expression during cardiopulmonary bypass: a comparative study of roller and centrifugal pumps. Perfusion 1997; 12:293–301.
Lindholm L, Westerberg M, Bengtsson A, Ekroth R, Jensen E, Jeppsson A. A closed perfusion system with heparin coating and centrifugal pump improves cardiopulmonary bypass biocompatibility in elderly patients. Ann Thorac Surg 2004; 78:2131–2138.
Mullen JC, Bentley MJ, Gelfand ET, Koshal A, Modry DL, Guenther CR, Etches WS, Stang LJ, Lopushinsky SR. Coronary artery bypass surgery with heparin-coated perfusion circuits and low-dose heparinization. Can J Surg 2002; 45:166–172.
Babin-Ebell J, Misoph M, Mullges W, Neukam K, Elert O. Reduced release of tissue factor by application of a centrifugal pump during cardiopulmonary bypass. Heart Vessels 1998; 13:147–151.
Wheeldon DR, Bethune DW, Gill RD. Vortex pumping for routine cardiac surgery: a comparative study. Perfusion 1990; 5:135–143.
Zirbel GM, Letson ME, Kauffman JN, Walker CT, Guyton RA. Hematologic derangements of cardiopulmonary bypass: a comparison of two perfusion systems. J Extra Corporeal Technol 1990; 22:15–19.
Misoph M, Babin-Ebell J, Schwender S. A comparative evaluation of the effect of pump type and heparin-coated surfaces on platelets during cardiopulmonary bypass. Thorac Cardiovasc Surg 1997; 45:302–306.
Murakami F, Usui A, Hiroura M, Kawamura M, Koyama T, Murase M. Clinical study of totally roller pumpless cardiopulmonary bypass system. Artif Organs 1997; 21:803–807.
Moen O, Fosse E, Dregelid E, Brockmeier V, Andersson C, Hogasen K, Venge P, Mollnes TE, Kierulf P. Centrifugal pump and heparin coating improves cardiopulmonary bypass biocompatibility. Ann Thorac Surg 1996; 62:1134–1140.
Yoshikai M, Hamada M, Takarabe K, Okazaki Y, Ito T. Clinical use of centrifugal pumps and the roller pump in open heart surgery: a comparative evaluation. Artif Organs 1996; 20:704–706.
Perttila J, Salo M, Peltola O. Comparison of the effects of centrifugal versus roller pump on the immune response in open-heart surgery. Perfusion 1995; 10:249–256.
Steinbrueckner BE, Steigerwald U, Keller F, Neukam K, Elert O, Babin-Ebell J. Centrifugal and roller pumps – are there differences in coagulation and fibrinolysis during and after cardiopulmonary bypass. Heart Vessels 1995; 10:46–53.
Nishinaka T, Nishida H, Endo M, Miyagishima M, Ohtsuka G, Koyanagi H. Less blood damage in the impeller centrifugal pump: a comparative study with the roller pump in open heart surgery. Artif Organs 1996; 20:707–710.
Jakob HG, Hafner G, Thelemann C, Sturer A, Prellwitz W, Oelert H. Routine extracorporeal circulation with a centrifugal or roller pump. ASAIO Trans 1991; 37:M487–M489.(Julius Asante-Siaw, James)