Utility of central venous pressure measurement in renal transplantation: Is it evidence based?

Anesthesia and intensive care unit care in pediatric kidney transplantation: An international survey

BACKGROUND

Despite the high perioperative risk profile, international guidelines for anesthesia and intensive care unit (ICU) care in pediatric kidney transplantation do not exist. Optimizing hemodynamics can be challenging in these patients, while scientific data to guide decisions in hemodynamic monitoring, hemodynamic targets, and perioperative fluid management are lacking. The limited annual number of pediatric kidney transplantations, even in reference centers, necessitates the urge for international collaboration to share knowledge and develop research and guidelines. The aim of this study was to collect data on current perioperative anesthesia and ICU care practices in pediatric kidney transplantation.

METHODS

An international survey with an anonymized link was sent from a validated electronic data capture system (Castor). Inclusion criteria were: medical doctor in anesthesia, (ICU), or pediatric nephrology working in a pediatric kidney transplantation specialized center; and signed informed consent. Data were analyzed using descriptive statistics.

RESULTS

Thirty-three records were analyzed. Responders were anesthesiologists (58%), pediatric nephrologists (30%), and pediatric intensivists (12%), representing 13 countries worldwide. About half of the centers (48%) performed more than 10 pediatric kidney transplantations a year. Perioperative hemodynamic support was guided by intra-arterial blood pressure (88%), central venous pressure (CVP; 88%), and cardiac output (CO; 39%). The most variation was seen in the hemodynamic targets CVP and CO, fluid administration, and inotrope/vasopressor use. The protocolized use of furosemide (46%) and mannitol (61%) also varied between centers. Postoperative care for the youngest recipients occurred in the pediatric intensive care unit at all centers.

CONCLUSION

The results of this survey reveal a large variation in anesthesia and ICU care in pediatric kidney transplantation centers worldwide, particularly in CVP and CO targets, hemodynamic therapy, and the use of furosemide and mannitol. These data identify areas for further research and can be a starting point for international research collaboration and guideline development.

A comparative study of pulse pressure variation, stroke volume variation and central venous pressure in patients undergoing kidney transplantation

Introduction

Optimal intraoperative fluid management guided by central venous pressure (CVP), a traditional intravascular volume status indicator, has improved transplanted graft function during kidney transplantation (KT). Pulse pressure variation (PPV) and stroke volume variation (SVV) - dynamic preload indexes - are robust predictors of fluid responsiveness. This study aimed to compare the accuracy of PPV and CVP against SVV in predicting fluid responsiveness in terms of cost-effectiveness after a standardised empiric volume challenge in KT patients.

Methods

36 patients undergoing living-donor KT were analysed. PPV, SVV, CVP and cardiac index (CI) were measured before and after fluid loading with a hydroxyethyl starch solution (7 mL/kg of ideal body weight). Patients were classified as responders (n = 12) or non-responders (n = 24) to fluid loading when CI increases were ≥10% or <10%, respectively. The ability of PPV, SVV and CVP to predict fluid responsiveness was assessed using receiver operating characteristic (ROC) curves.

Results

SVV and CVP measured before fluid loading were correlated with changes in CI caused by fluid expansion (ρ = 0.33, P = 0.049 and ρ = -0.37, P = 0.026) in contrast to PPV (ρ = 0.14, P = 0.429). The ROC analysis showed that SVV and CVP predicted response to volume loading (area under the ROC curve = 0.781 and 0.727, respectively; P < 0.05).

Conclusion

Under the conditions of our study, SVV and CVP exhibited similar performance in predicting fluid responsiveness and could inform fluid management during KT as compared with PPV.

Anesthetic Challenges and Perioperative Factors Affecting Delayed Graft Function in Robotic-Assisted Kidney Transplant: A Review of a Single-Center Experience of 100 Cases

Background and objective

The advent of robot-assisted kidney transplant (RAKT) has ushered in a new set of challenges. In this single-center retrospective observational study, we aimed to highlight the anesthetic challenges and analyze perioperative parameters to identify the risk factors for delayed graft function (DGF) in RAKT.

Methods

A descriptive analysis of perioperative factors of the first 100 cases of RAKT at our center was performed. Data were retrieved from the hospital's electronic medical records (EMR) of donors and adult patients who underwent RAKT between July 2015 and December 2020. The data analyzed included demographics, preoperative optimization, intraoperative and postoperative management, and complications. DGF was defined as a requirement of dialysis within one week of transplant. The Fisher’s exact test, independent sample t-test, and the Mann-Whitney test were used to analyze data.

Results

Among a total of 193 renal transplants performed during the study period, 100 patients underwent RAKT, which included 27 females and 73 males. Of these, 91 were live while the remaining involved deceased-donor transplants. Pneumoperitoneum and steep Trendelenburg position required various “anesthetic maneuvers” to maintain hemodynamics and respiratory parameters. Optimal fluid management, with frusemide and mannitol, ensured good urine output (UOP) (93%). Post-reperfusion, the release of pneumoperitoneum, maintenance of adequate perfusion pressures, immunosuppression, and regional hypothermia helped in ensuring adequate graft function (93%). The incidence of DGF in our series was 7% and the mortality rate was 3%. Recipient age (p=0.045), dyslipidemia (p=0.021), and diabetes mellitus (p=0.023) were identified as significant risk factors for DGF.

Conclusion

Advanced recipient age, diabetes, and dyslipidemia were factors significantly associated with DGF in RAKT in our series of 100 cases. However, the duration of the steep Trendelenburg position, docking of robot/pneumoperitoneum (console time), fluid management, warm and cold ischemia times, rewarming time, and type of graft did not influence DGF. Awareness of the systemic involvement in RAKT, proper preoperative optimization, and knowledge of potential problems are essential for the efficient anesthetic management of RAKT.

Influence of Intraoperative Hemodynamic Parameters on Outcome in Simultaneous Pancreas-Kidney Transplant Recipients

Objectives: Adequate organ perfusion, as well as appropriate blood pressure levels at the time of unclamping, is crucial for early and long-term graft function and outcome in simultaneous pancreas−kidney transplantation (SPKT). However, the optimal intraoperative mean arterial pressure (MAP) level has not well been defined. Methods: From a prospectively collected database, the medical data of 105 patients undergoing SPKT at our center were retrospectively analyzed. A receiver operating characteristic (ROC) analysis was preliminarily performed for optimal cut-off value for MAP at reperfusion, to predict early pancreatic graft function. Due to these results, we divided the patients according to their MAP values at reperfusion into <91 mmHg (n = 47 patients) and >91 mmHg (n = 58 patients) groups. Clinicopathological characteristics and outcomes, as well as early graft function and long-term survival, were retrospectively analyzed. Results: Donor and recipient characteristics were comparable between both groups. Rates of postoperative complications were significantly higher in the <91 mmHg group than those in the >91 mmHg group (vascular thrombosis of the pancreas: 7 (14%) versus 2 (3%); p = 0.03; pancreatitis/intraabdominal abscess: 10 (21%) versus 4 (7%); p = 0.03; renal delayed graft function (DGF): 11 (23%) versus 5 (9%); p = 0.03; postreperfusion urine output: 106 ± 50 mL versus 195 ± 45 mL; p = 0.04). There were no significant differences in intraoperative volume repletion, central venous pressure (CVP), use of vasoactive inotropic agents, and the metabolic outcome. Five-year pancreas graft survival was significantly higher in the >91 mmHg group (>91 mmHg: 82% versus <91 mmHg: 61%; p < 0.01). No significant differences were observed in patient and kidney graft survival at 5 years between both groups. Multivariate Cox regression analysis affirmed MAP < 91 mmHg as an independent prognostic predictor for renal DGF (HR 3.49, 1.1−10.8, p = 0.03) and pancreas allograft failure (HR 2.26, 1.0−4.8, p = 0.01). Conclusions: A MAP > 91 mmHg at the time point of reperfusion was associated with a reduced rate of postoperative complications, enhancing and recovering long-term graft function and outcome and thus increasing long-term survival in SPKT recipients.

Crystalloid fluids and delayed graft function in kidney transplant: A cohort study

Background:

Normal saline is commonly used in the perioperative kidney transplant period; its high chloride content can cause hyperchloremic metabolic acidosis giving a possible advantage to balanced electrolyte solutions due to their lower chloride content. The evidence regarding the best practices in fluid management during kidney transplantation and its effect on the incidence of delayed graft function (DGF) is still limited.

Materials and Methods:

One hundred thirty-eight patients were included and followed up for seven days after surgery. Administered crystalloid type and volume were compared among patients with and without DGF, along with additional patient and surgical variables. To investigate whether intraoperative fluid type/amount influence DGF, patients were categorized into three groups: those who received mainly (>50%) lactated Ringer's solution, normal saline, or plasmaLyte. A logistic regression analysis was used to define variables independently correlated with DGF, and odds ratios (OR) with a 95% confidence interval (CI) were reported.

Results:

The incidence of DGF was 8.7%. Cold ischemia time independently increased the odds of DGF (OR = 1.006 (95% CI: 1.002–1.011) while fluid type (saline versus PlasmaLyte OR = 5.28, 95% CI: 0.76–36.88) or amount (OR = 1.00, 95% CI: 1.00–1.01) did not significantly modify the odds of DGF. Central venous pressure, systolic blood pressure, and mean arterial pressure were higher in the non-DGF group, but this was not statistically significant (P > 0.05). Significant intraoperative acidosis developed in patients who received normal saline compared to those in PlasmaLyte and lactated Ringer's groups; however, acid–base balance and electrolytes did not vary significantly between the DGF and non-DGF groups.

Conclusion:

DGF was primarily influenced by surgical factors such as cold ischemia time, whereas intraoperative fluid type or amount did not affect DGF incidence.

A randomized comparison between pulse pressure variation and central venous pressure in patients undergoing renal transplantation

Background and Aims:

Intraoperative fluid management is important in renal transplant recipients with end-stage renal disease. Conventionally, central venous pressure (CVP) has been used to guide perioperative fluid administration but with high incidence of poor graft outcome. There is a requirement of reliable parameter to guide the fluid therapy in these patients so as to minimize the perioperative complications and improve the outcome. Hence, this study was conducted.

Material and Methods:

This prospective study included 75 patients of chronic kidney disease undergoing renal transplantation. Patients were divided into two groups. Group A (control group): Intraoperative fluids were guided by CVP; Group B: Intraoperative fluids were guided by pulse pressure variation (PPV). Primary outcome measure of this study was incidence of delayed graft functioning, i.e., need of hemodialysis within 7 days of renal transplant. Secondary outcome measures were incidence of perioperative hypotension, post-transplant pulmonary edema, tissue edema, and lactic acidosis.

Results:

Total amount of fluid before reperfusion was significantly greater in the control group (P = 0.005). However, the total amount of fluid required at the end of surgery was comparable. Delayed graft functioning was seen only in CVP group, although it was not statistically significant. The postoperative tissue edema was more in CVP group (P = 0.03). The postoperative nausea and vomiting, pulmonary edema, and mechanical ventilation were more in CVP group but not statistically significant. Increase in lactate value was more in CVP group.

Conclusion:

Perioperative fluid guidance by PPV is better than central venous pressure in renal transplant patients.

To compare intraoperative goal directed fluid therapy by trans-oesophageal Doppler vis-à-vis FloTrac™ in patients undergoing living related renal transplantation-a prospective randomised controlled study

Background:

Optimal intra-operative fluid therapy in renal transplantation (RT) is essential to ensure adequate graft function while preventing fluid overload related complications. This RCT was to compare the intraoperative goal directed fluid therapy (GDFT) based either on corrected flow time (CFT), measured by trans oesophageal Doppler (TED) or on the stroke volume variation (SVV), by FloTrac in patients undergoing living donor RT.

Methods:

This prospective, randomised controlled trial (RCT) was done on 60 end stage renal disease (ESRD) patients, American Society of Anaesthesiologists(ASA) grade III–IV, age 18 to 65 years of either sex, scheduled for living donor RT under general anaesthesia. They were randomly divided into two groups: TED group (n = 30) and FloTrac™ group (n = 30) and administered GDFT, based upon CFT (TED) and SVV (FloTrac™). The primary outcome was to compare the total fluid and number of fluid boluses administered intraoperatively, while the secondary outcomes were to compare any postoperative complications due to fluid overload and allograft function, assessed by serial serum creatinine levels up to 90 days postoperatively.

Results:

The mean total intra-operative fluid [3991.67 ± 856.32 vs. 3543.33 ± 1131.35, P = 0.089] and the amount of fluid administered per kg body weight per hour [13.32 ± 4.67 vs. 11.82 ± 4.76, P = 0.222] were lesser in the FloTrac compared to TED group, though not statistically significant. However, the postoperative incidence of allograft dysfunction, including rejection (P = 0.743) and acute tubular necrosis (ATN) (P = 0.999), and other complications (P = 0.643) were comparable.

Conclusions:

Both TED and FloTrac devices can be used effectively to guide GDFT in RT, However, lesser total fluid was required in the FloTrac group, which may lead to a lesser number of fluid-related postoperative complications.

Cardiac output-guided hemodynamic therapy for adult living donor kidney transplantation in children under 20 kg: A pilot study

BACKGROUND

A living-donor (adult) kidney transplantation in young children requires an increased cardiac output to maintain adequate perfusion of the relatively large kidney. To achieve this, protocols commonly advise liberal fluid administration guided by high target central venous pressure. Such therapy may lead to good renal outcomes, but the risk of tissue edema is substantial.

AIMS

We aimed to evaluate the safety and feasibility of the transpulmonary thermodilution technique to measure cardiac output in pediatric recipients. The second aim was to evaluate whether a cardiac output-guided hemodynamic therapy algorithm could induce less liberal fluid administration, while preserving good renal results and achieving increased target cardiac output and blood pressure.

METHODS

In twelve consecutive recipients, cardiac output was measured with transpulmonary thermodilution (PiCCO device, Pulsion). The algorithm steered administration of fluids, norepinephrine and dobutamine. Hemodynamic values were obtained before, during and after transplantation. Results are given as mean (SD) [minimum-maximum].

RESULTS

Age and weight of recipients was 3.2 (0.97) [1.6-4.9] yr and 14.1 (2.4) [10.4-18] kg, respectively. No complications related to cardiac output monitoring occurred. After transplantation, cardiac index increased with 31% (95% CI = 15%-48%). Extravascular lung water and central venous pressure did not change. Fluids given decreased from 158 [124-191] mL kg^-1 in the first 2 patients to 80 (18) [44-106] mL kg^-1 in the last 10 patients. The latter amount was 23 mL kg^-1 less (95% CI = 6-40 mL kg^-1 ) than in one recent study, but similar to that in another. After reperfusion, all patients received norepinephrine (maximum dose 0.45 (0.3) [0.1-0.9] mcg kg^-1  min^-1 ). Patient and graft survivals were 100% with excellent kidney function at 6 months post-transplantation.

CONCLUSION

Transpulmonary thermodilution-cardiac output monitoring appeared to be safe and feasible. Using the cardiac output-guided algorithm led to excellent renal results with a trend toward less fluids in favor of norepinephrine.