Relative Importance of Flow versus Pressure in Splanchnic Perfusion during Cardiopulmonary Bypass in Rabbits (original) (raw)
Related papers
British Journal of Anaesthesia, 1999
Decreased gut perfusion has been reported during cardiopulmonary bypass (CPB). Studies of treatments to avoid splanchnic ischaemia during CPB have given conflicting results. We studied 12 rabbits during mild hypothermic non-pulsatile CPB. Tissue blood flow in three different splanchnic areas (gastric, jejunum and ileum) was measured by laser Doppler velocimetry (LDV) before CPB (T0), after steady state (T1), after administration of dopexamine 2 µg kg -1 min -1 (T2) and 4 µg kg -1 min -1 (T3), and after return to baseline (T4). Splanchnic blood flow decreased during CPB. Dopexamine increased significantly jejunum LDV (100% at T1 to mean 271 (SD 210)% at T2) and ileum LDV (100% at T1 to 187 (112)% at T2). Gastric LDV was not altered by infusion of dopexamine during CPB. This could partly explain the conflicting results on the value of gastric tonometry as an index of splanchnic injury. Br J Anaesth 1999; 82: 104-9 References 1 Mythen MG, Webb AR. The role of gut mucosal hypoperfusion in the pathogenesis of postoperative organ dysfunction. Intensive Care Med 1994; 20: 203-9 2 Andersen LW, Landow L, Baek L, Jansen E, Baker S. Association between gastric intramucosal pH and splanchnic endotoxin, antibody to endotoxin, and tumor necrosis factor-alpha concentrations in patients undergoing cardiopulmonary bypass. Crit Care Med 1993; 21: 210-17 3 Bastien O, Piriou V. The immune response to cardiopulmonary bypass. Curr Opin Anesthesiol 1996; 9: 76-80 4 Hall RI, Smith MS, Rocker G. The systemic inflammatory response to cardiopulmonary bypass: pathophysiological, therapeutic and pharmacological considerations. Anesth Analg 1997; 85: 766-82 5 Booker PD, Prosser DP, Franks R. Effect of hypothermia on rectal mucosal perfusion in infants undergoing cardiopulmonary bypass. Br J Anaesth 1996; 77: 591-6 6 Lazenby WD, Ko W, Zelano JA, et al. Effects of temperature and flow rate on regional blood flow and metabolism during cardiopulmonary bypass. Ann Thorac Surg 1992; 53: 957-64 7 Ohri SK, Becket J, Brannan J, Keogh BE, Taylor KM. Effects of cardiopulmonary bypass on gut blood flow, oxygen utilization, and intramucosal pH. Ann Thorac Surg 1994; 57: 1193-9 8 Ohri SK, Somasundaram S, Koak Y, et al. The effect of intestinal hypoperfusion on intestinal absorption and permeability during cardiopulmonary bypass. Gastroenterology 1994; 106: 318-23 9 Uusaro A, Ruokonen E, Takala J. Gastric mucosal pH does not reflect changes in splanchnic blood flow after cardiac surgery. Br J Anaesth 1995; 74: 149-54 10 Mackay JH, Feerick AE, Woodson LC, et al. Increasing organ blood flow during cardiopulmonary bypass in pigs: comparison of dopamine and perfusion pressure. Crit Care Med 1995; 23: 1090-8 11 Meier-Hellmann A, Bredle DL, Specht M, et al. The effects of low-dose dopamine on splanchnic blood flow and oxygen uptake in patients with septic shock. Intensive Care Med 1997; 23: 31-7
Acta Anaesthesiologica Scandinavica, 2005
An imbalance between splanchnic oxygen supply and demand occurs during cardiopulmonary bypass (CPB) in man, which might disrupt the intestinal mucosal barrier function. The aim of the present study was to evaluate the effects of mild hypothermic CPB on intestinal mucosal perfusion in man undergoing cardiac surgery. Additionally we aimed to identify variables, which independently could predict changes of intestinal mucosal microcirculatory variables during CPB. Jejunal mucosal perfusion (JMP), jejunal mucosal hematocrit (JMHt), red blood cell (RBC) velocity and arteriolar vasomotion using endoluminal jejunal laser Doppler flow metry were studied in eight cardiac surgical patients before and during CPB at a temperature of 34 degrees C. Cardiopulmonary bypass and the accompanied hemodilution (25-30%) induced a 44% increase in JMP (P < 0.05) and a 42% increase in RBC velocity (P < 0.01), with no change in JMHt. The oscillation amplitude of JMP, at a fundamental frequency of 2.8 cycles min(-1), increased with 175% (P < 0.05) during CPB. Splanchnic oxygen extraction increased by 64% during CPB (P < 0.05). Stepwise multiple regression analysis identified systemic hematocrit, arterial O2 and CO2 tension and splanchnic oxygen extraction as independent predictors of RBC velocity during CPB (R2=0.63, P < 0.001). The oscillation amplitude of JMP was predicted by RBC velocity and splanchnic oxygen extraction (R2= 0.68, P <0.0001). The increase in RBC velocity and enhanced arteriolar vasomotion, as well as maintained jejunal mucosal hematocrit, are microcirculatory, compensatory mechanisms for the splanchic oxygen supply/demand mismatch seen during cardiopulmonary bypass in humans.
Effects of cardiopulmonary bypass on gut blood flow, oxygen utilization, and intramucosal pH
Annals of Thoracic Surgery, 1994
Studies documenting rises in endotoxin after cardiopulmonary bypass (CPB) have postulated gut mucosal hypoperfusion. We have investigated alterations in jejunal blood flow by laser Doppler flow measurement, intramucosal pH (plHi) by tonometry, and oxygen utilization in a canine model of hypothermic CPB (n = 11 dogs). After 10 minutes of hypothermic CPB, despite no major reduction in superior mesenteric artery flow, mucosal laser Doppler flow decreased to -38.2% f 9.3% of levels obtained before bypass ( p = 0.008) and serosal laser Doppler flow, to -47.3% : k 11.4% (p = 0.006). During the hypothermic phase, mescmteric oxygen consumption fell from 0.18 2 0.01 to 0.098 f 0.01 mL * min-' * kg-' (p = 0.005), and mesenteric oxygen delivery fell from 1.97 2 0.39 to 1.14 2 0.12 mL emin-'. kg-' ( p = 0.05). There was no change in jejunal pHi. During the rewarming phase, he gastrointestinal tract has been acknowledged as a
Journal of Thoracic and Cardiovascular Surgery, 1995
Impaired gut mucosal perfusion has been reported during cardiopulmonary bypass. To better define the adequacy of gut blood flow and oxygenation during cardiopulmonary bypass, we measured overall gut blood flow and ileal mucosal flow and their relationship to mucosal pH, mesenteric oxygen delivery and oxygen consumption in immature pigs (n = 8). Normothermic, noncrossclamped, right atrium-to-aorta cardiopulmonary bypass was maintained at 100 ml/kg per minute for 120 minutes. Animals were instrumented with an ultrasonic Doppler flow probe on the superior mesenteric artery, a mucosal laser Doppler flow probe in the ileum, and pH tonometers in the stomach, ileum, and rectum. Radioactive microspheres were injected before and at 5, 60, and 120 minutes of cardiopulmonary bypass for tissue blood flow measurements. Overall gut blood flow siguificantly increased during cardiopulmonary bypass as evidenced by increases in superior mesenteric arterial flow to 134.1% _ 8.0%, 137.1% ± 7.5%, 130.3% _ 11.2%, and 130.2% -12.7% of baseline values at 30, 60, 90, and 120 minutes of bypass, respectively. Conversely, ileal mucosal blood flow significantly decreased to 53.6% _ 6.4%, 49.5% + 6.8%, 58.9% ± 11.6%, and 47.8% ± 10.0% of baseline values, respectively. Blood flow measured with microspheres was siguificantly increased to proximal portions of the gut, duodenum änd jejunum, during cardiopulmonary bypass, whereas blood flow to distal portions, ileum and colon, was unchanged. Gut mucosal pH decreased progressively during cardiopulmonary bypass and paralleled the decrease in ileal mucosal blood flow. Mesenteric oxygen delivery decreased significantly from 67.0 ± 10.0 ml/min per square meter at baseline to 42.4 ± 4.6, 44.9 ± 3.5, 46.0 _ 3.6, and 42.9 -+ 3.9 ml/min per square meter at 30, 60, 90, and 120 minutes of bypass. Despite the decrease in mesenteric oxygen delivery, mesenteric oxygen consumption increased progressively from 10.8 ± 1.4 ml/min per square meter at baseline to 13.4 ± 1.2, 15.9 ± 1.2, 16.7 ± 1.4, and 16.6 ± 1.54 ml/min per square meter, respectively. We conclude that gut mucosal ischemia during normothermic cardiopulmonary bypass results from a combination of redistribution of blood flow away from mucosa and an increased oxygen demand. (J THORAC CARDIOVASC SURG 1995;110:819-28)
The International Journal of Artificial Organs, 2005
Background Current pulsatile pumps for cardiopulmonary bypass (CPB) are far from satisfactory because of the poor pulsatility. This study was undertaken to examine the efficiency of a novel pulsatile catheter pump on pulsatility and its effect on abdominal organ perfusion during CPB. Methods Twelve pigs weighing 89±11 kg were randomly divided into a pulsatile group (n=6) and a non-pulsatile group (n=6). All animals had a CPB for 120 min, aorta clamped for 60 min, temperature down to 32°C, and a perfusion flow of 60 ml/kg/min. In the pulsatile group, a 21 Fr intra-aortic pulsatile catheter, which was connected to a 40 mL membrane pump, was placed in the descending aorta and activated by a balloon pump driver during the first 90 minutes of CPB until aortic declamping. Hemodynamics, organ blood flow, body metabolism, and blood trauma were studied during experiments. Results Compared with the non-pulsatile group during CPB, the pulsatile group had a higher systolic blood pressure (P&0.0...
The Journal of surgical research, 2011
BACKGROUND Utilization of thromboresistant circuits in cardiopulmonary bypass (CPB) surgery has been controversial. However, due to the advantages associated with these types of circuits, we sought to evaluate the efficacy of use of low-dose heparin in conjunction with thromboresistant surfaces, closed perfusion system, elimination of blood-gas interface, maintenance of hematocrit to >25%, and systemic normothermia, with respect to the conventional strategy of non-thromboresistant open circuits with high-dose heparin, during 3 h of CPB in an animal model. METHODS Using an open-chest swine model, animals were placed on CPB for 3 h with additional monitoring for 1 h post-CPB. Pigs were randomized into either a heparin-bonded circuit (HBC) group (n = 10) or a non-HBC (NHB) group (n = 10). Hemodynamic, hematologic, and biochemical parameters and multiphoton microscopy were used to compare the two groups. RESULTS Pigs in the HBC group showed a 38.4% reduction in post-CPB blood loss in...
Effect of Cardiopulmonary Bypass on Gastrointestinal Perfusion and Function
The Annals of thoracic …, 1994
Gastric mucosal tonometry was used to determine the adequacy of gastrointestinal perfusion in 10 patients undergoing elective myccardial revascularization. Patients were prospectively randomized to receive either pulsatile or nonpulsatile flow during cardlopulmonary ...
Low arterial pressure during cardiopulmonary bypass in piglets does not decrease fluid leakage
Acta Anaesthesiologica Scandinavica, 2005
Approaching the end of this work, I would like to thank my supervisor professor Paul Husby for his support, ideas and never failing optimism when confronted with expected and unexpected obstacles along the way. His generosity in sharing his time and experience with the group is unique and was most appreciated. I also would like to express my gratitude to my colleague and friend Marit Farstad who, besides introducing me to the laboratory, has assisted me in the conduct of most of the experiments and participated in numerous intriguing and constructive discussions. The contribution by my colleague Stig Hammersborg and Hege Brekke by taking care of many tedious tasks during the labor intensive experiments was also highly appreciated. Furthermore, I would like to acknowledge the thoracic surgeons Stein Erik Rynning and Venny Kvalheim who have provided me with excellent surgery throughout theses studies. Associate professor Olav Egil Bøe has repeatedly given us advices regarding statistical processing of the data. We are grateful for his valuable support.
The Journal of Thoracic and Cardiovascular Surgery, 2013
Objective: To evaluate how pulsed versus nonpulsed cardiopulmonary bypass influences microvascular fluid exchange in an experimental setup combining a nonpulsatile perfusion pump and an intra-aortic balloon pump. Methods: A total of 16 pigs were randomized to pulsatile cardiopulmonary bypass perfusion with an intra-aortic balloon pump switched to an automatic 80 beats/min mode after the start of cardiopulmonary bypass (pulsatile perfusion [PP] group, n ¼ 8) or to nonpulsatile cardiopulmonary bypass with the pump switched to the off position (nonpulsatile [NP] group, n ¼ 8). Normothermic cardiopulmonary bypass was initiated after 60 minutes of stabilization and continued for 3 hours. The fluid needs, plasma volume, colloid osmotic pressure in plasma, colloid osmotic pressure in interstitial fluid, hematocrit, and total tissue water content were recorded, and the protein masses and fluid extravasation rates were calculated. Results: After cardiopulmonary bypass was started, the mean arterial pressure increased in the PP group and decreased in the NP group. At 180 minutes, the mean arterial pressure of the PP and NP groups was 70.9 AE 2.7 mm Hg and 55.9 AE 2.7 mm Hg, respectively (P ¼ .004). The central venous pressure (right atrium) had decreased in the NP group (P ¼ .002). A decreasing trend was seen in the PP group. No between-group differences were present. The hematocrit and colloid osmotic pressure in plasma and interstitial fluid had decreased similarly in both study groups during cardiopulmonary bypass. The plasma volume of the PP group had decreased initially but then returned gradually to precardiopulmonary bypass levels. In the NP group, the plasma volume remained contracted (P ¼ .02). No significant differences in the fluid extravasation rate were obtained. The fluid extravasation rate of the PP group tended to stay slightly higher than the fluid extravasation rate of the NP group at all measurement intervals. The total tissue water content increased significantly in a number of organs compared with that in the control animals. However, differences in the total tissue water content between pulsed and nonpulsed perfusion were absent. Conclusions: No significant differences in the fluid extravasation rates were present between pulsed and nonpulsed cardiopulmonary bypass perfusion in the present experimental setup.