Nonpulsatile Group Research Articles

Pulsatile Right Ventricle to Pulmonary Artery Extracorporeal Membrane Oxygenation in a Pigs

Background: We investigated the impact of right ventricle to pulmonary artery extracorporeal membrane oxygenation in acute respiratory dysfunction with or without pulsatile flow. Methods: We used bronchoalveolar lavage with intrapulmonary administration of warm saline to establish a severe acute respiratory distress syndrome model (ratio of partial pressure of oxygen in arterial blood to the fraction of inspiratory oxygen concentration ratio <200) in eight piglets (mean body weight: 8.45±1.24 kg). The piglets were categorized into the pulsatile (N=4) and non-pulsatile extracorporeal membrane oxygenation groups (N=4). We started right ventricle to pulmonary artery extracorporeal membrane oxygenation with a 60 mL/kg/min flow to support the animals for 6 hours. We monitored hemodynamic data and blood gas levels for assessing base excess, and performed arterial blood sampling and electrocardiogram. Interleukin-6 and endotherlin-1 concentrations in blood plasma were evaluated before and after right ventricle to pulmonary artery extracorporeal membrane oxygenation. We compared the lung wet/dry weight ratio as a measure of pulmonary edema and collected lung tissue samples for the pathologically evaluating pneumocytes before and after right ventricle to pulmonary artery extracorporeal membrane oxygenation. Results: We maintained stable hemodynamics and extracorporeal membrane oxygenation flow above an arterial oxygen saturation of 85% in both groups. Pneumocyte evaluation showed clearly less pulmonary edema, pulmonary fibrosis, and inflammation. Interleukin-6 concentration was less in the pulsatile group than in the non-pulsatile group. Conclusions: Pulsatile right ventricle to pulmonary artery extracorporeal membrane oxygenation was less vasoconstrictive and maintained more effective oxygenated pulmonary flow. It ameliorates pulmonary circulation and facilitates recovery from acute respiratory failure.

The effects of pulsatile versus nonpulsatile flow on cerebral pulsatility index, mean flow velocity at the middle cerebral artery, regional cerebral oxygen saturation, cerebral gaseous microemboli counts, and short-term clinical outcomes in patients undergoing congenital heart surgery

ObjectiveThe objective of this retrospective review was to evaluate whether or not pulsatile flow improves cerebral hemodynamics and clinical outcomes in pediatric congenital cardiac surgery patients. MethodsThis retrospective study included 284 pediatric patients undergoing congenital cardiac surgery with cardiopulmonary bypass support utilizing nonpulsatile (n = 152) or pulsatile (n = 132) flow. Intraoperative cerebral gaseous microemboli counts, pulsatility index, and mean blood flow velocity at the right middle cerebral artery were assessed using transcranial Doppler ultrasound. Clinical outcomes were compared between groups. ResultsPatient demographics and cardiopulmonary bypass characteristics between groups were similar. Although the pulsatility index during aortic crossclamping was consistently higher in the pulsatile group (P < .05), a significant degree of pulsatility was also observed in the nonpulsatile group. No significant differences in mean cerebral blood flow velocity, regional cerebral oxygen saturation, or gaseous microemboli counts were observed between the perfusion modality groups. Clinical outcomes, including intubation duration, intensive care unit and hospital length of stay, and mortality within 180 days were similar between groups. ConclusionsAlthough the pulsatility index was greater in the pulsatile group, other measures of intraoperative cerebral perfusion and short-term outcomes were similar to the nonpulsatile group. These findings suggest that while pulsatile perfusion represents a safe modality for cardiopulmonary bypass support, its use may not translate into detectably superior clinical outcomes.

A Randomized Clinical Trial of Perfusion Modalities in Pediatric Congenital Heart Surgery Patients

BackgroundThe objective of this randomized clinical trial was to investigate the effects of perfusion modalities on cerebral hemodynamics, vital organ injury, quantified by the Pediatric Logistic Organ Dysfunction-2 (PELOD-2) Score, and clinical outcomes in risk-stratified congenital cardiac surgery patients. MethodsThis randomized clinical trial included 159 consecutive congenital cardiac surgery patients in whom pulsatile (n = 83) or nonpulsatile (n = 76) perfusion was used. Cerebral hemodynamics were assessed using transcranial Doppler ultrasound. Multiple organ injury was quantified using the PELOD-2 score at 24, 48, and 72 hours. Clinical outcomes, including intubation time, intensive care unit length of stay (LOS), hospital LOS, and mortality, were also evaluated. ResultsThe Pulsatility Index at the middle cerebral artery and in the arterial line during aortic cross-clamping was consistently better maintained in the pulsatile group. Demographics and cardiopulmonary bypass characteristics were similar between the 2 groups. While risk stratification with The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) Mortality Categories was similar between the groups, Mortality Categories 1 to 3 demonstrated more patients than Mortality Categories 4 and 5. There were no differences in clinical outcomes between the groups. The PELOD-2 scores showed a progressive improvement from 24 hours to 72 hours, but the results were not statistically different between the groups. ConclusionsThe Pulsatillity Index for the pulsatile group demonstrated a more physiologic pattern compared with the nonpulsatile group. While pulsatile perfusion did not increase plasma-free hemoglobin levels or microemboli delivery, it also did not demonstrate any improvements in clinical outcomes or PELOD-2 scores, suggesting that while pulsatile perfusion is a safe method, it not a “magic bullet” for congenital cardiac operations.

Efficacy of Pulsatile Flow Perfusion in Adult Cardiac Surgery: Hemodynamic Energy and Vascular Reactivity.

Background: The role of pulsatile (PP) versus non-pulsatile (NP) flow during a cardiopulmonary bypass (CPB) is still debated. This study’s aim was to analyze hemodynamic effects, endothelial reactivity and erythrocytes response during a CPB with PP or NP. Methods: Fifty-two patients undergoing an aortic valve replacement were prospectively randomized for surgery with either PP or NP flow. Pulsatility was evaluated in terms of energy equivalent pressure (EEP) and surplus hemodynamic energy (SHE). Systemic (SVRi) and pulmonary (PVRi) vascular resistances, endothelial markers levels and erythrocyte nitric-oxide synthase (eNOS) activity were collected at different perioperative time-points. Results: In the PP group, the resultant EEP was 7.3% higher than the mean arterial pressure (MAP), which corresponded to 5150 ± 2291 ergs/cm3 of SHE. In the NP group, the EEP and MAP were equal; no SHE was produced. The PP group showed lower SVRi during clamp-time (p = 0.06) and lower PVRi after protamine administration and during first postoperative hours (p = 0.02). Lower SVRi required a higher dosage of norepinephrine in the PP group (p = 0.02). Erythrocyte eNOS activity results were higher in the PP patients (p = 0.04). Renal function was better preserved in the PP group (p = 0.001), whereas other perioperative variables were comparable between the groups. Conclusions: A PP flow during a CPB results in significantly lower SVRi, PVRi and increased eNOS production. The clinical impact of increased perioperative vasopressor requirements in the PP group deserves further evaluation.

The effect of pulsatile versus non-pulsatile flow during cardiopulmonary bypass on cerebral oxygenation: A randomized trial.

The present study aims to compare regional oxygen supply determined by Near-Infrared Spectroscopy in the course of pulsatile perfusion with non-pulsatile perfusion during cardiopulmonary bypass in patients undergoing valvular heart surgery. In this prospective randomized single-blinded trial, we enrolled adult subjects aged 18-65 years scheduled for elective valvular heart repair/replacement surgery with non-stenotic carotid arteries, employing a consecutive sampling method. Eligible patients were then randomly assigned in a 1:1 ratio to pulsatile or non-pulsatile perfusion during aortic cross-clamp. The primary outcome was regional cerebral oxygenation monitored by Near-Infrared Spectroscopy in each group. Seventy patients were randomly assigned, and each group comprised 35 patients. Mean age was 46.8 and 46.5 years in pulsatile and non-pulsatile groups, respectively. There were no significant between-group differences in regional cerebral oxygen saturation at different time points of cardiopulmonary bypass (p-value for analysis of variance repeated measures: 0.923 and 0.223 for left and right hemispheres, respectively). Moreover, no significant differences in regional cerebral oxygen saturation levels from baseline between pulsatile and non-pulsatile groups at all desired time points for the left (p = 0.51) and right (p = 0.22) hemispheres of the brain were detected. Pulsatile perfusion during cardiopulmonary bypass does not offer superior regional cerebral oxygenation measured by Near-Infrared Spectroscopy than non-pulsatile perfusion during cardiopulmonary bypass. Nonetheless, the efficacy of pulsatile flow in the subgroup of patients in whom cerebral blood flow is impaired due to carotid artery stenosis needs to be explored and evaluated by this method in future studies.

Pulsatility protects the endothelial glycocalyx during extracorporeal membrane oxygenation.

Pulsatile flow protects vital organ function and improves microcirculatory perfusion during extracorporeal membrane oxygenation (ECMO). Studies revealed that pulsatile shear stress plays a vital role in microcirculatory function and integrity. The objective of this study was to investigate how pulsatility affects wall shear stress and endothelial glycocalyx components during ECMO. Using the i-Cor system, sixteen canine ECMO models were randomly allocated into the pulsatile or the non-pulsatile group (eight canines for each). Hemodynamic parameters, peak wall shear stress (PWSS), serum concentration of syndecan-1, and heparan sulfate were measured at different time points during ECMO. Pulsatile shear stress experiments were also performed in endothelial cells exposed to different magnitudes of pulsatility (five plates for each condition), with cell viability, the expressions of syndecan-1, and endothelial-to-mesenchymal transformation (EndMT) markers analyzed. The pulsatile flow generated more surplus hemodynamic energy and preserved higher PWSS during ECMO. Serum concentrations of both syndecan-1 and heparan sulfate were negatively correlated with PWSS, and significantly lower levels were observed in the pulsatile group. Besides, non-pulsatility triggered EndMT and endothelial cells exposed to low pulsatility had the lowest possibility of EndMT. The maintenance of the PWSS by pulsatility during ECMO possesses beneficial effects on glycocalyx integrity. Moreover, pulsatility prevents EndMT in endothelial cells, and low pulsatility exhibits the best protective effects. The augmentation of pulsatility may be a plausible future direction to improve the clinical outcome in ECMO.

The Pulsatile Modification Improves Hemodynamics and Attenuates Inflammatory Responses in Extracorporeal Membrane Oxygenation.

BackgroundCOVID-19 is still a worldwide pandemic and extracorporeal membrane oxygenation (ECMO) is vital for extremely critical COVID-19 patients. Pulsatile flow impacts greatly on organ function and microcirculation, however, the effects of pulsatile flow on hemodynamics and inflammatory responses during ECMO are unknown. An in vivo study was launched aiming at comparing the two perfusion modes in ECMO.MethodsFourteen beagles were randomly allocated into two groups: the pulsatile group (n=7) and the non-pulsatile group (n=7). ECMO was conducted using the i-Cor system for 24 hours. Hemodynamic parameters including surplus hemodynamic energy (SHE), energy equivalent pressure (EEP), oxygenator pressure drop (OPD), and circuit pressure drop (CPD) were monitored. To assess inflammatory responses during ECMO, levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8, and transforming growth factor-β1 (TGF-β1) were measured.ResultsEEP and SHE were markedly higher in pulsatile circuits when compared with the conventional circuits. Between-group differences in both OPD and CPD reached statistical significance. Significant decreases in TNF-α were seen in animals treated with pulsatile flows at 2 hours, 12 hours, and 24 hours as well as a decrease in IL-1β at 24 hours during ECMO. The TGF-β1 levels were significantly higher in pulsatile circuits from 2 hours to 24 hours. The changes in IL-6 and IL-8 levels were insignificant.ConclusionThe modification of pulsatility in ECMO generates more hemodynamic energies and attenuates inflammatory responses as compared to the conventional non-pulsatile ECMO.

Changes in intraocular pressure during coronary artery bypass graft surgery: an observational study

BackgroundIn this study, the effects of pulsatile and non-pulsatile on-pump Coronary Artery Bypass Graft surgery (CABG) and off-pump CABG techniques on the intraocular pressure were investigated. MethodsForty-five patients who planned to elective coronary artery bypass surgery with on-pump pulsatile (n=15), non-pulsatile (n=15), or off-pump (n=15) were included. Intraocular Pressure (IOP) measurements were performed on both eyes at nine time-points: 1) Before the operation, 2) After anesthesia induction, 3) 3 minutes after heparin administration Left Internal Mammary Artery (LIMA) harvesting, 4) End of the first anastomosis, 5) End of LIMA anastomosis, 6) 3 minutes after protamine administration, 7) End of the operation, and 8) Second hour in Intensive Care Unit (ICU), 9) Fifth hour in ICU. Mean Arterial Pressure (MAP) and Central Venous Pressure (CVP) were also recorded at the same time points as IOP. ResultsIn Cardiopulmonary Bypass (CPB) groups (pulsatile or non-pulsatile CPB) with the beginning of CPB, there were significant decreases in IOP values when compared to baseline (p=0.012). This decrease was more prominent in the non-pulsatile group when compared to the pulsatile group (T4 IOP values: pulsatile, 9.7±2.6; non-pulsatile, 6.8±1.9; p=0.002; T5 IOP values: pulsatile, 9.5±1.9; non-pulsatile, 6.7±2.1; p=0.004). At the end of the surgery (T7), IOP values returned to the baseline and stayed stable at the remaining time-points. In-off pump group, IOP values significantly increased with a head-down position (T4 IOP values: off-pump surgery, 19.7±5.2; p=0.015). IOP values remained high until the normalization of head-down position (T6) and stayed stable through the rest of all remaining time-points. ConclusionDuring cardiac surgery regardless of the technique (on-pump CABG, off-pump CABG), intraocular pressures remain in the normal ranges. It should be kept in mind that patients should be avoided from long and extreme Trendelenburg position, low CVP, and MAP levels during cardiac surgery to prevent eye-related complications.

Post-Fontan pulmonary artery growth in patients with a bidirectional cavopulmonary shunt with additional antegrade pulsatile blood flow.

Patients with antegrade pulmonary blood flow after a bidirectional cavopulmonary shunt (Glenn) may have better pulmonary artery growth. This study evaluated pulmonary artery growth in patients with and without prior additional pulsatile antegrade flow in a Glenn shunt at midterm follow-up after a Fontan procedure. We reviewed 212 patients who had single-ventricle palliation in a 10-year period;103 (33 in pulsatile group 1 and 70 in nonpulsatile group 2) were selected for analysis. Data on demographics, procedures, perioperative course, and midterm follow-up after the Fontan procedure were compared. Echocardiography data were collected. Pulmonary artery sizes measured at cardiac catheterization and follow-up echocardiograms were used to calculate the Nakata index. Perioperative details were comparable in both groups, mean pulmonary artery pressure and systemic oxygen saturations were higher in group 1 compared to group 2. Venovenous collaterals were increased in group 1. There was a significant difference in the pre-Fontan and follow-up Nakata index between groups. There was a significant increase in the Nakata index in group 1 between the pre-Glenn and pre-Fontan assessments as well as the Nakata index between the pre-Fontan and midterm follow-up. There was no significant change in the Nakata index in group 2 between assessments. A pulsatile Glenn shunt is associated with better pulmonary artery growth which continues long after the additional pulsatile flow is eliminated. It is possible that the effects of anterograde pulmonary blood flow on pulmonary artery growth in early life continue long after the Fontan completion.

Sleep Quality after Coronary Artery Bypass Graft Surgery: Comparing Pulsatile and Nonpulsatile Pump Flow

Poor postoperative sleep quality is a common problem in patients undergoing coronary artery bypass graft surgery (CABG). The purpose of this study was to compare the effect of pulsatile and nonpulsatile pump flow on sleep quality of these patients. In this clinical trial, 52 patients undergoing on pump CABG surgery with the roller pump were randomly divided into two equal groups of 26 patients: group 1 using pulsatile pump flow and group 2 nonpulsatile pump flow while the heart was arrested. Sleep score of both groups was evaluated by Pittsburgh Sleep Quality Index questionnaire 2 days before operation and 1 month after operation, and they were compared with each other. Analysis was performed with SPSS software version 22 (SPSS for Windows Inc., Chicago, IL) using the independentt-test, chi-square test, and Fisher exact test. Both groups were the same in demographic characteristics and risk factors such as age, gender, diabetes mellitus, hypertension, hyperlipidemia, smoking, body mass index, and preoperative ejection fraction. Operation data showed no difference between two groups considering cardiopulmonary bypass time and cardiac arrest time. Preoperative sleep quality score of both groups had no significant difference (p= .84). One month postoperative sleep quality score of the pulsatile group was significantly better than that of the nonpulsatile group (p= .04). Using pulsatile flow cardiopulmonary bypass can effectively decrease postoperative sleep disorders in comparison to nonpulsatile flow.

Sleep Quality after Coronary Artery Bypass Graft Surgery: Comparing Pulsatile and Nonpulsatile Pump Flow.

Poor postoperative sleep quality is a common problem in patients undergoing coronary artery bypass graft surgery (CABG). The purpose of this study was to compare the effect of pulsatile and nonpulsatile pump flow on sleep quality of these patients. In this clinical trial, 52 patients undergoing on pump CABG surgery with the roller pump were randomly divided into two equal groups of 26 patients: group 1 using pulsatile pump flow and group 2 nonpulsatile pump flow while the heart was arrested. Sleep score of both groups was evaluated by Pittsburgh Sleep Quality Index questionnaire 2 days before operation and 1 month after operation, and they were compared with each other. Analysis was performed with SPSS software version 22 (SPSS for Windows Inc., Chicago, IL) using the independent t-test, chi-square test, and Fisher exact test. Both groups were the same in demographic characteristics and risk factors such as age, gender, diabetes mellitus, hypertension, hyperlipidemia, smoking, body mass index, and preoperative ejection fraction. Operation data showed no difference between two groups considering cardiopulmonary bypass time and cardiac arrest time. Preoperative sleep quality score of both groups had no significant difference (p = .84). One month postoperative sleep quality score of the pulsatile group was significantly better than that of the nonpulsatile group (p = .04). Using pulsatile flow cardiopulmonary bypass can effectively decrease postoperative sleep disorders in comparison to nonpulsatile flow.

Investigation of the Effect of Pulsatile and Nonpulsatile Flow on Kidney in Coronary Surgery With NIRS.

Acute renal insufficiency is a significant cause of morbidity and mortality after coronary artery bypass grafting performed with cardiopulmonary bypass. Functional near-infrared spectroscopy (fNIRS) is an emerging brain-imaging technique that can be used to detect organ perfusions in adults. This study aims to determine the effects of pulsatile and nonpulsatile flow on renal circulation by using functional near-infrared spectroscopy and biochemical markers. Forty patients, who had undergone isolated CABG between March 2014 and July 2014 in the authors' clinic, were included in the study. Patients were divided in the pulsatile and nonpulsatile groups by simple randomization. Urine outputs statistically were higher in the pulsatile group, during CPB (P = .045). Renal perfusion measurements via fNIRS intra-operatively statistically were parallel between the groups. When we compared biochemical markers within the groups, in the nonpulsatile group, creatinin statistically is higher on the postoperative first day (P = .003), and BUN statistically is higher on the postoperative first (P = .015), second (P = .001), and fifth (P = .020) days, according to preoperative value. In the pulsatile group, only the postoperative second day BUN is higher (P = .007). fNIRS is being used to track cerebral functions. During operation, it also provides a correct observation for blood feeding of somatic organs, such as the kidneys, but it requires more clinical study to be accepted as routine.

Pulsatile Versus Nonpulsatile Flow During Cardiopulmonary Bypass: Extent of Hemolysis and Clinical Significance.

Pulsatile flow has been used during cardiopulmonary bypass (CPB) for decades and its use is increasing with advancing extracorporeal technology. Pulsatile flow generates higher circuit pressures and shear forces than nonpulsatile flow at comparable pump flow and patient mean arterial pressure. Very little is known about the effect this has on erythrocytes. We included 62 adult patients (32 in the pulsatile group and 30 in the nonpulsatile group) undergoing elective coronary artery bypass grafting in this prospective observational study. Blood samples were collected at routine sampling times throughout surgery and were analyzed for the presence of free heme and globin using mass spectroscopy. Patient characteristics, CPB, and aortic cross-clamp times, pump flow as well as patient mean arterial pressure were similar in both groups. Maximum circuit pressure in the pulsatile flow group was statistically significantly higher than that in the nonpulsatile flow group (257.12 vs. 190.64 mmHg, p < 0.0001). Both heme and globin levels were higher in the pulsatile flow group. This reached statistical significance with globin at 30 minutes of CPB and with heme after aortic unclamping. We conclude that pulsatile CPB using roller pumps results in a greater extent of hemolysis. The clinical significance, however, is not yet known.

The Association Between Pulsatile Cardiopulmonary Bypass and Acute Kidney Injury After Cardiac Surgery: A Before-and-After Study

To investigate the association between pulsatile perfusion and cardiac surgery-associated acute kidney injury. An uncontrolled, retrospective before-and-after study. Single tertiary hospital. A total of 2,489 patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Pulsatile versus nonpulsatile perfusion. Data for nonpulsatile perfusion was collected from April 1, 2016, to March 31, 2017 (n = 1,223). A practice change to universal pulsatile CPB occurred on April 3, 2017. Data for pulsatile perfusion was collected from May 1, 2017, to June 30, 2018 (n = 1,266). The primary outcome was the incidence of acute kidney injury (AKI) after cardiac surgery. Multivariable analysis was carried out to adjust for known confounders. Secondary outcomes included AKI stage, stroke, length of stay, and mortality. Subgroup analyses were carried out using prolonged CPB and chronic kidney disease. The primary outcome, incidence of AKI, did not differ between the nonpulsatile control group and the pulsatile group (23.9% v 25.4%, p = 0.392). The pulsatile group was not associated with AKI in the multivariable analysis (Odds ratio 1.09, p = 0.413). There were no differences in stages of AKI in the nonpulsatile group v pulsatile group (13.6% v 14.9%, 2.9% v 4.3%, and 7.4% v 6.1% for stages 1, 2, and 3, respectively, p = 0.12). There were no differences in subgroup analyses or secondary outcomes. There was no association found between kidney injury and pulsatile perfusion. It is likely that there is either no association between pulsatile perfusion and reduced kidney injury or that the difference is extremely small.

Early Gastrointestinal Complications From Ventricular Assist Devices is Increased by Non-Pulsatile Flow

Measurements of organ flow and perfusion during cardiopulmonary bypass suggest that perfusion of the splanchnic bed can be impaired by non-pulsatile flow. We postulated that non-pulsatile flow from centrifugal ventricular assist devices might also compromise splanchnic blood flow and cause bowel ischaemia especially in the period of circulatory instability early post-implant. The aim of the present studies was to compare the incidence of gastrointestinal (GI) complications in patients having a non-pulsatile device with the incidence in those having a pulsatile device. In a pilot study, the initial 12 patients who received the Ventrassist (Ventracor, Sydney, NSW, Australia) centrifugal, non-pulsatile device during the period from June 2003 to September 2005 at the Alfred Hospital, Melbourne were compared with 11 patients who received a Thoratec (Thoratec, Pleasanton, CA, USA), pulsatile, positive displacement device and the incidence was recorded of GI complications requiring an intervention either surgical, endoscopic or by interventional radiology. This was followed by a larger (full) study of a second cohort of similar ventricular assist device (VAD) patients from January 1992 until December 2012 comparing 53 patients having non-pulsatile devices and 110 having pulsatile devices. In the pilot study, the overall incidence of complications in the non-pulsatile group (67%) was almost double that in the pulsatile group (36%) but the difference was not statistically significant (p = 0.15) because of the small number (n = 23) of participants. In the full study, all GI complications with either device occurred within the first 3 weeks post-implant. In the non-pulsatile patients, there was a higher incidence of GI bleeding, 23% vs 4% (p = 0.002), endoscopies, 24% vs 12% (p = 0.049). More patients with a non-pulsatile flow device had delayed absorption of nasogastric feeds than their pulsatile counterparts, 35% vs 7% (p < 0.0001). Patients with a non-pulsatile flow device had a higher overall rate of gastrointestinal complications than patients had with a pulsatile flow device, 56% vs 20% (p < 0.0001). After correcting for the other predictors, the odds of developing a gastrointestinal complication in the pulsatile group was significantly lower (odds ratio 0.07) than in the non-pulsatile device group (p < 0.0001). We conclude that the use of non-pulsatile centrifugal VADs compared with pulsatile positive displacement VADs is associated with a higher incidence of both haemorrhagic and ischaemic complications in the gastro-intestinal system especially in the very early post-implant period. Whether these complications could be reduced in centrifugal devices by increasing their pulsatility is not clear and merits further research.

Improved Outcome in an Animal Model of Prolonged Cardiac Arrest Through Pulsatile High Pressure Controlled Automated Reperfusion of the Whole Body.

The reperfusion period after extracorporeal cardiopulmonary resuscitation has been recognized as a key player in improving the outcome after cardiac arrest (CA). Our aim was to evaluate the effects of high mean arterial pressure (MAP) and pulsatile flow during controlled automated reperfusion of the whole body. Following 20 min of normothermic CA, high MAP, and pulsatile blood flow (pulsatile group, n = 10) or low MAP and nonpulsatile flow (nonpulsatile group, n = 6) controlled automated reperfusion of the whole body was commenced through the femoral vessels of German landrace pigs for 60 min. Afterwards, animals were observed for eight days. Blood samples were analyzed throughout the experiment and a species-specific neurologic disability score (NDS) was used for neurologic evaluation. In the pulsatile group, nine animals finished the study protocol, while no animal survived postoperative day four in the nonpulsatile group. NDS were significantly better at any given time in the pulsatile group and reached overall satisfactory outcome values. In addition, blood analyses revealed lower levels of lactate in the pulsatile group compared to the nonpulsatile group. This study demonstrates superior survival and neurologic outcome when using pulsatile high pressure automated reperfusion following 20 min of normothermic CA compared to nonpulsatile flow and low MAP. This study strongly supports regulating the reperfusion period after prolonged periods of CA.

Effect of pulsatile flow perfusion on decellularization

BackgroundDecellularized animal organs have been used as scaffolds for tissue engineering. To make a properly functioning scaffolds, the extracellular matrix (ECM) components must be preserved after decellularization. Because pulsatile flow is known to be beneficial for tissue perfusion, pulsatile perfusion of a detergent might decrease the exposure time of the tissues to the detergent used for decellularization. Using Energy Equivalent Pressure (EEP) as a pulsatility parameter, the effect of pulsatile flow in decellularization process is studied.ResultsTwelve rat hearts were decellularization with 1% sodium dodecyl sulfate (SDS) solution for 2 h. They are divided into two groups, one with pulsatile perfusion (n = 6), the other with non-pulsatile perfusion (n = 6) of SDS. The initial mean perfusion pressures were same in both group. The result indicated that the EEP and the perfusion flow were increased significantly in the pulsatile group compared to the non-pulsatile group. Photographs taken during the decellularization showed more profound decellularization in the pulsatile group. The residual DNA content in the scaffolds was significantly lower in the pulsatile group. However, the level of ECM components, collagen and GAG showed no significant differences between the groups.ConclusionsDecellularization is more efficient in pulsatile flow than in non-pulsatile flow but still preserves the ECM molecules.

Microvascular Responsiveness to Pulsatile and Nonpulsatile Flow During Cardiopulmonary Bypass

Pulsatile perfusion may offer microcirculatory advantages over conventional nonpulsatile perfusion during cardiopulmonary bypass (CPB). Here, we present direct visual evidence of microvascular perfusion and vasoreactivity between perfusion modalities. A prospective, randomized cohort study of 20 high-risk cardiac surgical patients undergoing pulsatile (n= 10) or nonpulsatile (n= 10) flow during CPB was conducted. Changes in sublingual mucosal microcirculation were assessed with orthogonal polarization spectral imaging along with near-infrared spectroscopic indices of thenar muscle tissue oxygen saturation (StO2) and its recovery during a vascular occlusion test at the following time points: baseline (T0), 30 minutes on CPB (T1), 90 minutes on CPB (T2), 1 hour after CPB (T3), and 24 hours after CPB (T4). On the basis of our scoring scale, a shift in microcirculatory blood flow occurred over time. The pulsatile group maintained normal perfusion characteristics, whereas the nonpulsatile group exhibited deterioration in perfusion during CPB (T2: 74.0% ± 5.6% versus 57.6% ± 5.0%) and after CPB (T3: 76.2% ± 2.7% versus 58.9% ± 5.2%, T4: 85.7% ± 2.6% versus 69.8% ± 5.9%). Concurrently, no important differences were found between groups in baseline StO2 and consumption slope at all time points. Reperfusion slope was substantially different between groups 24 hours after CPB (T4: 6.1% ± 0.6% versus 3.7% ± 0.5%), indicating improved microvascular responsiveness in the pulsatile group versus the nonpulsatile group. Pulsatility generated by the roller pump during CPB improves microcirculatory blood flow and tissue oxygen saturation compared with nonpulsatile flow in high-risk cardiac surgical patients, which may reflect attenuation of the systemic inflammatory response and ischemia-reperfusion injury.

An Assessment of Renal Function with Pulsatile Perfusion During Proximal Graft Using Cardiac Contraction in Coronary Artery Bypass Graft Surgery

Background: Short-term pulsatile perfusion during cardio pulmonary bypass has shown higher protection for renal physiology, following standard preservation of glomerular filtration and reduction of renal tissue damage. Methods: In this randomized clinical trial study, 70 patients, who had undergone CABG surgery were divided to 2 groups; pulsatile and non-pulsatile groups. The researchers transferred continuous blood flow to pulsatile blood flow during proximal graft using cardiac contraction. Patients’ laboratory tests, such as blood urea nitrogen (BUN) and creatinine were checked preoperatively, at the arrival of the open heart intensive care unit (ICU-OH), and 24 and 48 hours after admission. Results: Both case and control groups had significantly increased BUN and creatinine. Increased creatinine on the first and second postoperative day was significantly higher in the control group. Furthermore, BUN increased on the second day in the control group and was significantly higher than the case group Conclusions: Despite the rise in BUN and creatinine in the 2 groups, there were no cases of renal failure in the patients. However, the results of this study regarding creatinine and BUN criteria were supported by the pulsatile perfusion method during the proximal graft by using a cardiac contraction in CABG surgery.

Changes in intraocular pressure during cardiopulmonary bypass.

The aim of the present study was to investigate the changes in intraocular pressures (IOP) in patients who underwent pulsatile and non-pulsatile cardiopulmonary bypass (CPB). A total of 42 patients operated for elective coronary bypass surgery (CABG) on CPB were randomly allocated to pulsatile (Group P) and non-pulsatile (Group N) groups. Pulsatile flow was applied to Group P patients during crops-clamp period. The IOP measurements were made before and after the induction of anesthesia, before the onset of CPB, on the 5th, 15th, 30th, 45th, and 60thmin of CPB, after CPB and at the end of the operation. The results of repetitive measurements were analyzed at different intervals and in two groups. The second IOP measurements of right and left eyes displayed statistically significant decreases from the baseline level [11.9±2.9 (p=0.0001) and 12.5±3.2 (p=0.0001), respectively]. The significant decrease in the IOP values persisted in the repeated measurements except for the 5thmin of CPB values [17.0±3.5 (p=0.346) and 16.7±3.6 (p=0.399)]. Comparison of two groups demonstrated significant differences at pre-CPB (right 12.8±2.3 vs. 10.8±2.4; p=0.013 and left 13.3±2.4 vs. 11.5±2.5; p=0.023), and 5thmin of CPB measurements (right 18.5±3.1 vs. 15.9±3.4; p=0.015; left 18.2±3.0 vs. 15.7±3.6; p=0.019). We noted a steady decrease in repeated IOP measurements except for the transient increase in CPB values on 5thmin. The IOP values were higher in pulsatile CPB group in pre-CPB and 5thmin of CPB measurements; however, the difference was not significant in the repeated measurements.