Clinical effectiveness of centrifugal pump to produce pulsatile flow during cardiopulmonary bypass in patients undergoing cardiac surgery

Although the centrifugal pump has been widely used as a nonpulsatile pump for cardiopulmonary bypass (CPB), little is known about its performance as a pulsatile pump for CPB, especially on its efficacy in producing hemodynamic energy and its clinical effectiveness. We performed a study to evaluate whether the Rotaflow centrifugal pump produces effective pulsatile flow during CPB and whether the pulsatile flow in this setting is clinically effective in adult patients undergoing cardiac surgery. Thirty-two patients undergoing CPB for elective coronary artery bypass grafting were randomly allocated to a pulsatile perfusion group (n = 16) or a nonpulsatile perfusion group (n = 16). All patients were perfused with the Rotaflow centrifugal pump. In the pulsatile group, the centrifugal pump was adjusted to the pulsatile mode (60 cycles/min) during aortic cross-clamping, whereas in the nonpulsatile group, the pump was kept in its nonpulsatile mode during the same period of time. Compared with the nonpulsatile group, the pulsatile group had a higher pulse pressure (P < 0.01) and a fraction higher energy equivalent pressure (EEP, P = 0.058). The net gain of pulsatile flow, represented by the surplus hemodynamic energy (SHE), was found much higher in the CPB circuit than in patients (P < 0.01). Clinically, there was no difference between the pulsatile and nonpulsatile groups with regard to postoperative acute kidney injury, endothelial activation, or inflammatory response. Postoperative organ function and the duration of hospital stay were similar in the two patient groups. In conclusion, pulsatile CPB with the Rotaflow centrifugal pump is associated with a small gain of EEP and SHE, which does not seem to be clinically effective in adult cardiac surgical patients.     

Fluid and pain management in liver surgery (MILESTONE): A worldwide study among surgeons and anesthesiologists

Background

Fluid and pain management during liver surgery (eg, low central venous pressure) is a classic topic of controversy between anesthesiologists and surgeons. Little is known about practices worldwide. The aim of this study was to assess perioperative practices in liver surgery among and between surgeons and anesthesiologists worldwide that could guide the design of future international studies.

Troubleshooting the rat model of cardiopulmonary bypass: Effects of avoiding blood transfusion on long-term survival,inflammation and organ damage

IntroductionRat models of cardiopulmonary bypass (CPB) have been used to examine the mechanisms of associated organ damage and to test intervention strategies. However, these models only partly mimic the clinical situation, because of the use of blood transfusion and arterial inflow via the tail artery. Thus a model using arterial inflow in the aorta and a miniaturized CPB circuit without need of transfusion was validated by examining intra-procedure characteristics, mortality and the effects of CPB on biomarkers of inflammation and cerebral injury during 5 days follow-up.MethodsMale Wistar rats (n = 95) were anesthetized with isoflurane (2.5%) and fentanyl/midazolam during CPB. Animals were assigned to Control (n = 6), Sham (n = 40) or normothermic CPB (n = 49) groups. Both Sham and CPB were cannulated in the aorta via the left carotid artery and in the right common jugular vein for access into the right heart. Extracorporeal circulation (ECC) was instituted for 60 min only in CPB at a flow rate of 120 mL kg^? 1 min^? 1 employing a CPB circuit of 15 ml primed with 6% hydroxyethyl starch 60 mg ml^? 1 solution. Rats were sacrificed at either 1 h or 1, 2 or 5 days after Sham or weaning from CPB. Plasma IL-6 and s100Beta levels were measured and blood cell counts were performed.ResultsMortality in CPB animals (3 out of 49) and Sham (4 out of 40) did not differ (chi-square = 0.46, dF = 1, P > 0.5). Compared to baseline (1.87 ± 0.46 1 10^9 cells/L), Sham procedure (cannulation and anesthesia) significantly increased blood neutrophil count at the end of the period matching ECC (6.34 ± 2.36 1 10^9 cells/L, P < 0.05). CPB induced neutrophilia which persisted during 24 h recovery. Also, CPB caused a rapid and prominent increase in plasma IL-6 from the first hour of the postoperative period (~ 1200 pg/ml) with continuation (50–90 pg/ml) up to 5th day of recovery. S100Beta levels were above detection level only in 3 out of 42 samples from CPB animals.DiscussionOur rat model of CPB without homologous blood transfusion produces a reproducible and reliable systemic inflammatory response, with low mortality rates on long term follow up. The model more closely mimics the human situation in respect to arterial inflow site and avoidance of blood transfusion. Thus, our CPB model is suitable to study its influence on systemic inflammation, ischemia–reperfusion injury, microcirculation and vascular dysfunction in vivo, and to evaluate potential therapeutic interventions.     

The use of neuromuscular blocking agents in noncardiac surgery after dynamic cardiomyoplasty

Dynamic cardiomyoplasty is a surgical treatment to improve cardiac performance in patients with end-stage heart failure by wrapping the latissimus dorsi muscle around the heart. The use of skeletal muscle raises concerns about the safety of neuromuscular blocking agents used during general anaesthesia in noncardiac surgery in patients after cardiomyoplasty. We describe the administration of rocuronium to a patient undergoing carotid endarterectomy 18 months after cardiomyoplasty. No clinically relevant effects on haemodynamics were observed. We conclude that the use of nondepolarising neuromuscular blocking agents for noncardiac surgery in patients after cardiomyoplasty does not compromise cardiac performance in a clinically relevant way, although the time between the cardiomyoplasty procedure and the use of nondepolarising neuromuscular blocking agents remains a concern.     

Partial left ventriculectomy (Batista procedure) for the treatment of terminal heart failure after rejection for heart transplantation

A woman aged 64 was severely handicapped by dyspnoea due to 'terminal heart failure' resulting from idiopathic dilated cardiomyopathy. The mitral valve was seriously insufficient; the coronary vessels were normal. The patient was not eligible for heart transplantation. Partial left ventriculectomy by Batista's method was performed and the mitral valve replaced by an artificial one. The left ventricular ejection fraction increased from 0.12 before the operation to 0.35 postoperatively and to 0.43 two years later. Patient was then capable of normal exercise (New York Heart Association (NYHA): class I-II). In the Netherlands partial left ventriculectomy is the last surgical option for patients rejected for heart transplantation.     

Surgeons' assessment versus risk models for predicting complications of hepato-pancreato-biliary surgery (HPB-RISC): a multicenter prospective cohort study

Background

Several studies advise the use of risk models when counseling patients for hepato-pancreato-biliary (HPB) surgery, but studies comparing these models to the surgeons' assessment are lacking. The aim of this study was to assess whether risk prediction models outperform surgeons' assessment for the risk of complications in HPB surgery.

Pressure drop, shear stress, and activation of leukocytes during cardiopulmonary bypass: a comparison between hollow fiber and flat sheet membrane oxygenators

The membrane oxygenator is known to be superior to the bubble oxygenator, but little information is available about the difference between the hollow fiber and flat sheet membrane oxygenators with regard to pressure drop, shear stress, and leukocyte activation. In this study, we compared these 2 types of membrane oxygenators in patients undergoing cardiopulmonary bypass (CPB) surgery with special focus on leukocyte activation and pressure drop across the oxygenators. Plasma concentration of elastase, a marker indicating leukocyte activation, increased to 593+/-68% in the flat sheet oxygenator group versus 197+/-42% in the hollow fiber oxygenator group (p<0.01) at the end of CPB compared to their respective baseline concentrations before CPB. Pressure drop across the oxygenator was significantly higher in the flat sheet group than in the hollow fiber group throughout the entire period of CPB (p<0.01). High pressure drop across the oxygenator as well as the calculated shear stress was positively correlated with the release of elastase at the end of CPB (r = 0.760, p<0.01, r = 0.692, p<0.01). However, this positive correlation existed in the flat sheet oxygenator but not in the hollow fiber oxygenator. Clinically, both membrane oxygenators have satisfactory performance in O2 and CO2 transfer. These results suggest that a higher pressure drop across the flat sheet oxygenator is associated with more pronounced activation of leukocytes in patients undergoing cardiopulmonary bypass.     

The role of abdominal drainage in pancreatic resection – A multicenter validation study for early drain removal

BackgroundAbdominal drainage and the timing of drain removal in patients undergoing pancreatic resection are under debate. Early drain removal after pancreatic resection has been reported to be safe with a low risk for clinical relevant postoperative pancreatic fistula (CR-POPF) when drain amylase on POD1 is < 5000U/L. The aim of this study was to validate this algorithm in a large national cohort.MethodsPatients registered in the Dutch Pancreatic Cancer Audit (2014–2016) who underwent pancreatoduodenectomy, distal pancreatectomy or enucleation were analysed. Data on post-operative drain amylase levels, drain removal, postoperative pancreatic fistulae were collected. Univariate and multivariate analysis using a logistic regression model were performed. The primary outcome measure was grade B/C pancreatic fistula (CR-POPF).ResultsAmong 1402 included patients, 433 patients with a drain fluid amylase level of <5000U/L on POD1, 7% developed a CR-POPF. For patients with an amylase level >5000U/L the CR-POPF rate was 28%. When using a cut-off point of 2000U/L or 1000U/L during POD1-3, the CR-POPF rates were 6% and 5% respectively. For patients with an amylase level of >2000U/L and >1000UL during POD 1–3 the CR-POPF rates were 26% and 22% respectively (n = 223). Drain removal on POD4 or thereafter was associated with more complications (p = 0.004). Drain amylase level was shown to be the most statistically significant predicting factor for CR-POPF (Wald = 49.7; p < 0.001).ConclusionOur data support early drain removal after pancreatic resection. However, a cut-off of 5000U/L drain amylase on POD1 was associated with a relatively high CR-POPF rate of 7%. A cut-off point of 1000U/L during POD1-3 resulted in 5% CR-POPF and might be a safer alternative.     

A combination of buprenorphine and naloxone compared with buprenorphine administered intramuscularly in postoperative patients

Sixty patients suffering from moderate to severe pain following either orthopaedic or gynaecological surgery were treated with intramuscular buprenorphine (0.3 mg) or an intramuscular combination of buprenorphine (0.3 mg)/naloxone (0.2 mg) and the analgesic efficacy and safety of the two treatments was compared. The evaluation of efficacy showed that both treatments provided good analgesia which was apparent at the first assessment time (10 minutes) and continued for approximately 10 hours. Only seven patients suffered from unwanted side-effects with only drowsiness/sleepiness and nausea being reported by more than one patient. Over-all analysis of the results showed that there were no significant differences between the two treatments with regard to efficacy and safety.