Luca Meacci

Evaluation of an uncalibrated arterial pulse contour cardiac output monitoring system in cirrhotic patients undergoing liver surgery

BACKGROUND The pulmonary artery catheter is invasive and may cause serious complications. A safe method of cardiac output (CO) measurement is needed. We have assessed the accuracy and reliability of a recently marketed self-calibrating arterial pulse contour CO monitoring system (FloTrac/Vigileo) in end-stage liver failure patients undergoing liver transplant. The pattern of alterations known as cirrhotic cardiomyopathy, and the transplant procedure itself, provided an evaluation under varying clinical conditions. METHODS The cardiac index was measured simultaneously by thermodilution (CI(TD): mean of four readings) using a pulmonary artery catheter and pulse contour analysis (CI(V): mean value computed by the FloTrac/Vigileo over the same time period). Readings were made at 10 time-points during liver transplant surgery (T1-T5) and on the intensive care unit (T6-T10). CI(V) was computed using the latest Vigileo software version 01.10. RESULTS A total of 290 paired readings from 29 patients were collected. Mean (SD) CI(TD) was 5.2 (1.3) and CI(V) was 3.9 (0.9) litre min(-1) m(-2), with a corrected for repeated measures bias between readings of 1.3 (0.2) litre min(-1) m(-2) and 95% limits of agreement of -1.5 (0.2) to 4.1 (0.3) litre min(-1) m(-2). The percentage error (2SD(Bias)/meanCI(TD)) was 54%, which exceeded a 30% limit of acceptance. Low peripheral resistance and increasing bias were related (r=0.69; P<0.001). The Vigileo system failed to reliably trend CI data, with a concordance compared with thermodilution below an acceptable level (at best 68% of sequential readings). CONCLUSIONS In cirrhotic patients with hyperdynamic circulation, the Vigileo system showed a degree of error and unreliability higher than that considered acceptable for clinical purposes.

Evaluation of a new software version of the FloTrac/Vigileo (version 3.02) and a comparison with previous data in cirrhotic patients undergoing liver transplant surgery.

BACKGROUND: Reliable cardiac output monitoring is particularly useful in the cirrhotic patient undergoing liver transplant surgery, because cirrhosis of the liver is associated with a vasodilated and high output state, known as cirrhotic cardiomyopathy, that challenges the reliability of pulse contour cardiac output technology. The contractility of the ventricle in cirrhosis is impaired, which is tolerated even though the ejection fraction and cardiac output are elevated because of the low peripheral resistance. However, during surgery the cirrhotic patient can decompensate because of the physiological changes and stress of surgery. Recently, we showed that the FloTrac/Vigileo™ failed to perform in cirrhotic patients undergoing transplant surgery. In response, the company upgraded their software. Therefore, we have assessed the accuracy and reliability of this new third-generation (version 3.02) FloTrac/Vigileo algorithm software in the same setting. METHODS: The cardiac index was measured simultaneously by single-bolus thermodilution (CITD), using a pulmonary artery catheter, and pulse contour analysis, using the FloTrac/Vigileo (CIV). Readings were made at 10 time points during and after liver transplant surgery in 21 patients. Comparisons with data from our 2009 study, which used second-generation (version 01.10) software, were also made. RESULTS: Our new data show that version 3.02 software significantly reduced the adverse effect on pulse contour cardiac output reading bias in low peripheral resistance states, and thus improves the overall precision and trending ability of the system. Regression analysis between CITD and CIV showed that the correlation was moderate (r =0.67, 95% confidence interval, 0.40 to 0.86). The Bland and Altman analysis showed that bias was 0.4 L.min−1 · m−2, and the percentage error was 52% (95% confidence interval, 49% to 55%). Trending ability of the new software also was improved but was still well below the current benchmarks. CONCLUSION: The new software (version 3.02) provided substantial improvements over the previous versions with better overall precision and trending ability. Further algorithm refinements will increase this technology’s reliability to be extensively used in the highly complex setting of cirrhotic patients undergoing liver transplantation.

Use of fenoldopam to control renal dysfunction early after liver transplantation.

With the aim of assessing whether fenoldopam can help to preserve renal function after liver transplantation, we randomized 140 consecutive recipients with comparable preoperative renal function to receive fenoldopam 0.1 μg/kg/minute (group F, 46 patients), dopamine 3 μg/kg/minute (group D, 48 patients), or placebo (group P, 46 patients) from the time of anesthesia induction to 96 hours postoperatively. There were no differences between the groups in intraoperative urinary output or furosemide administration (both P = .1). Daily recordings made during the first 4 postoperative days revealed no significant differences in urinary output (P = .1), serum creatinine (P = .5), the incidence of renal insufficiency (P = .7), the need for loop diuretics (P = .9) or vasoactive drugs (P = .8). In comparison with preoperative levels, creatinine clearance at the end of the study in the patients receiving fenoldopam remained substantially unchanged, whereas it decreased by 39 and 12.3%, respectively, in the subjects receiving placebo or dopamine (P < .001); blood cyclosporine A (CsA) levels were similar in the 3 groups (P = .1). Three subjects died in the intensive care unit (1 in each group, P = .9), 2 of them had renal failure. In conclusion, our results confirm the inefficacy of dopamine in preventing or limiting early renal dysfunction after liver transplantation, and suggest that fenoldopam may preserve creatinine clearance by counterbalancing the renal vasoconstrictive effect of CsA, as it has been reported in previous experimental studies. (Liver Transpl 2004;10:986–992.)

A new technique for total hepatectomy in the pig for testing liver support devices

BACKGROUND A large animal model of total hepatectomy is suitable to test the efficacy of any system designed to support patients in hepatic coma. The models previously described in the pig entail a significant degree of surgical trauma, which might alter the evolution of the ensuring hepatic failure and compromise the reproducibility of the model. METHODS Twenty-eight pigs underwent a total hepatectomy according to a new technique. A model was considered satisfactory when it required no blood transfusions and when hematologic and hemodynamic parameters determined before, during, and until 4 hours after hepatectomy showed no significant variations. Moreover, to revive the pattern of hepatic coma produced in the anhepatic model, 7 pigs were monitored until brain death occurred. RESULTS Twenty-five pigs (89%) underwent a smooth total hepatectomy with minimal variations of the selected parameters. They constituted a highly homogeneous group. Survival of the 7 pigs, followed up until brain death occurred, ranged from 625 to 1595 minutes (mean 1013.57 minutes). The animals remained stable until a few hours before brain death, an event heralded by a final sharp increase of the serum ammonia level and by a well-evident decline of both arterial pressure and liver-dependent clotting factors. CONCLUSIONS This technique of total hepatectomy allows the construction of a reproducible model of anhepaty suitable to test the efficacy of any system conceived to temporarily replace hepatic functions.

Solvent detergent vs. fresh frozen plasma in cirrhotic patients undergoing liver transplant surgery: a prospective randomized control study

Although orthotopic liver transplantation (OLT) is nowadays considered standard practice at experienced centres, it can still be affected by a significant risk of massive bleeding and its related complications. Solvent/detergent plasma (S/D Plasma) has been proposed as an alternative to fresh frozen plasma (FFP) to curtail such complications. This study aimed at evaluating the efficacy of S/D Plasma in OLT patients by comparing it to FFP.

Early morbidity after pancreas transplantation

This study aims to evaluate and compare the early outcome of both pancreas‐alone transplantation (PTA) and simultaneous kidney–pancreas transplantation (SPKT) focusing on the complications affecting the first month after the procedures. The records of all patients who underwent PTA or SPKT were reviewed. We considered the length of ICU stay, the need for postoperative ventilatory support, hemodynamic and metabolic data (arterial pH, serum glucose, need for exogenous insulin), infectious diseases incidence, microbiological colonization rate and any kind of postoperative complication arising during the first month after the transplantation. PTA recipients underwent a quicker surgery (P < 0.01) with shorter ICU stay (P < 0.05) and a lower need for postoperative mechanical ventilation (P < 0.05). They also had a higher hemodynamic stability (P < 0.05) with less cardiological complications (P < 0.05) in the intra‐ and postoperative phases; bacterial colonisation was also less frequent in PTA recipients (P < 0.05). On the contrary, no significant difference was noted with regard to postoperative nausea/vomiting, sudden myocardial death, ICU re‐admissions, graft function, rate of rejection, grafts explantation and re‐transplantation. PTA could be considered as preemptive for severe diabetic complications in patients with long‐lasting severe type I diabetes. However, establishing the correct timing of PTA is of paramount importance in order not to expose the patients early to risks arising from a major surgery and heavy immunosuppressive treatments.

Octogenarian donors in liver transplantation grant an equivalent perioperative course to ideal young donors

BACKGROUND Use of grafts from very old donors for liver transplantation is controversial. AIM To compare the perioperative course of patients receiving liver grafts from young ideal vs octogenarian donors. METHODS Analysis of the perioperative course of patients receiving liver grafts from young, ideal (18-39 years) vs octogenarian (≥80years) deceased donors between 2001 and 2014. RESULTS 346 patients were studied: 179 (51.7%) received grafts aged 18-39 years whereas 167 (48.3%) received a graft from a donor aged ≥80years. Intra-operative cardiovascular (p=0.2), coagulopathy (p=0.5) and respiratory (p=1.0) complications and incidence of reperfusion syndrome (p=0.3) were similar. Patients receiving a young graft required more fresh frozen plasma units (p≤0.03) but did not differ for the need of packed red cells (p=0.2) and platelet (p=0.3) transfusions. Median ICU stay was identical (p=0.4). Patients receiving octogenarian vs young grafts did not differ in terms of death or re-transplant (p=1.0) during the ICU stay. Similar cardiovascular, respiratory, renal, infectious and neurological postoperative complication rates were observed in the two groups. CONCLUSIONS Octogenarian donors in liver transplantation grant an equivalent perioperative course to ideal young donors.

A single-staggered dose of calcineurin inhibitor may be associated with neurotoxicity and nephrotoxicity immediately after liver transplantation

Abstract:  The aim of the present work was to assess the incidence of neuro‐nephrotoxicity after a single‐staggered dose of calcineurin inhibitors (CI) with different immunosuppressive approaches. From January to December 2006, all liver transplantation (LT) recipients at risk of renal or neurological complications treated with extracorporeal photopheresis (ECP) + mycophenolate mofetil + steroids and staggered introduction of CI (ECP group) were compared with a historical control group on standard CI‐based immunosuppression. The ECP group included 24 patients with a mean model for end‐stage liver disease (MELD) score of 19.9 ± 11.1. The control group consisted of 18 patients with a mean MELD score of 12.5 ± 5.2 (p = 0.012). In the ECP group CI were introduced at a mean of 9.2 ± 6.2 d (4–31 d) after LT. Five patients in the ECP group presented acute neuro‐nephrotoxicity after the first CI administration on post‐transplant d 4, 5, 6, 6, and 14. Overall patient survival at one, six, and 12 months was 100%, 95.8%, and 95.8% in the ECP group vs. 94.4%, 77.7%, and 72.2% in the control group (p < 0.001). In conclusion, we showed that CI toxicity may occur after a single‐staggered dose administration, ECP seems to be a valuable tool for managing CI‐related morbidity regardless of the concomitant immunosuppressive regimen, being associated with a lower mortality rate in the early post‐transplant course.

The challenges of diagnosing thrombotic thrombocytopenic purpura in the critically ill. A case report

Thrombotic thrombocytopenic purpura (TTP) is associated with high mortality rates. TTP may have various and different presentations depending on the organs involved. It is now recognized to be the consequence of reduction of blood levels of the disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-13. Prompt diagnosis of TTP is paramount, because plasma exchange is the only treatment capable of improving patients survival with a dual mechanism: removal of anti-ADAMTS-13 auto-antibodies and infusion of the active protease available in the fresh frozen plasma. We report herein on the challenges in diagnosing TTP-like complications of post-surgical facial surgery in a young male patient.