Preliminary Study on the Effect of Blood Purification Therapy with Dual-Cannula in Jugular-Femoral Venous: A Report of 2 Cases

The aim of the study is to investigate whether the multistage draining cannula strategy inserted via the femoral vein and with blood return to the jugular vein can improve the therapeutic efficiency in patients with vena cava drainage disorder compared to traditional hemodialysis therapy. This study was approved by the Review Board of the Ethics Committee of Zhongshan Hospital, Fudan University (No. B2022-380), and the need for obtaining signed informed consent was waived for this retrospective analysis. Two adult patients with acute vena cava reflux disorder were analyzed retrospectively in the study. To minimize recirculation, a multistage draining cannula strategy in a suitable position inserted via the femoral vein and with blood return to the jugular vein was used in patients with vena cava obstruction. Study endpoints included vasopressors equivalent dose, ICU outcome and other clinical outcomes. The results showed that blood purification based on dual-cannula in jugular-femoral venous was able to improve the hemodynamic state, reduce the vasopressors dosage and improve the outcome for critically ill patients with acute vena cava reflux disorder. Blood purification therapy with dual-cannula in jugular-femoral venous may be an effective and feasible strategy for patients with acute superior or inferior vena cava “obstruction”.


Introduction
In critically ill patients, acute kidney failure (AKI) is one of the most important causes of morbidity and mortality [1,2]. The treatment of AKI usually requires renal support such as continuous renal replacement therapy (CRRT), intermittent hemodialysis (IHD) and prolonged intermittent renal replacement therapies (PIRRTs) [3]. However, the efficiency of blood purification may be affected by the recirculation of double-lumen cannulation for special cases including patients with acute vena cava reflux disorder from massive abdominal tumor or ascites [4]. Recirculation is defined as the return of dialyzed blood to the arterial segment of the access bypassing the systemic circulation [5]. When recirculation is present, the dialyzed blood flow is composed of recirculated blood flow. Hence the existing dual-lumen catheter could not enable an adequate dialysis dose due to the high recirculation and diminish the dialysis dose. For extreme cases like patients with acute vena cava disconnection or severe obstruction, the traditional blood purification treatment cannot work effectively [6]. In the study reported here, we successfully treated two patients using dual-cannula in jugular-femoral venous for blood purification ( Fig. 1A and B) and found that it can improve dialysis adequacy and circulation status (Table 1)

Case 1
A 66 year-old female was diagnosed with retroperitoneal tumor. She was admitted to intensive care unit (ICU) after the surgical removal of the tumor together with the partial resection of inferior vena cava. On ICU admission, she occurred with hypovolemic shock, multiple organ dysfunction and disorder of consciousness (Fig. S1A). Due to the partial resection of inferior vena cava, postoperative cardiovascular complications including venous drainage obstruction and lower limb swelling occurred. To prevent the further injury from femoral venous catheterization to the stump of inferior vena cava, hemodialysis with one cannula in jugular venous was performed at first. However, the circulation status deteriorated and the dosage of vasopressors remained high. Given the situation, we considered one draining cannula in jugular venous ineffective for the recirculation in jugular venous. Therefore, we chose to drain the blood through femoral venous catheter and return the blood through jugular venous catheter to improve the perfusion of systemic circulation. The hemodynamic status improved greatly and then we gradually reduce the dosage of vasopressors. (Fig. 1C). Abdominal CT (computed tomography) showed that hepatic injury and intestinal swelling also improved (Fig. S1B). One week later, she successfully weaned from mechanical ventilation, transited to intermittent hemodialysis with only jugular venous catheter.

Case 2
A 58 year-old male was diagnosed with pancreatic neoplasm and radical pancreatoduodenectomy was performed 5 days after admission. On day 1 after operation, the patient was admitted into our ICU for sudden convulsion and severe shock. Computed tomography angiography (CTA) showed extensive thrombosis in superior mesenteric vein and portal vein after surgery (Fig. S1C). The possibility of portal vein obstruction was considered. Besides, the patient encountered oliguria with elevated creatinine, abnormal central venous pressure, tachycardia and high body temperature. To promote venous drainage into the inferior vena cava and improve circulation status, the patient was treated with dual-cannula hemodialysis via jugular-femoral venous. 24 h of urine volume and creatine level were recorded to evaluate the efficacy of dual-cannula hemodialysis. After 3 days of continuous hemodialysis, the renal function recovered, and the dosage of norepinephrine was reduced gradually with the improvement in circulation status (Fig. 1D). The oliguria and refractory ascites associated with portal vein obstruction decreased after the procedure. Abdominal CT showed intestinal edema was significantly improved (Fig. S1D). Given the clinical improvement, the patient was transformed from CRRT to intermittent hemodialysis for another 2 days.

Conclusion
Blood purification therapy with dual-cannula in jugularfemoral venous may be an effective and feasible strategy for patients with acute superior or inferior vena cava "obstruction".

Discussion
The renal function and hemodynamic status was improved in both patients (Table 2). Case 1 was successfully weaned from vasopressors, mechanical ventilation and endured another two operations, although she died of intestinal fistula after surgery two weeks later; case 2 was totally recovered and discharged from hospital. Both patients occurred severe shock due to the acute inferior vena cava reflux disturbance after operation. Consequently, current single-tube venous catheterization strategy could not effectively convey the blood from inferior vena cava to right atrium. Besides, severe congestion of abdominal organs and lower extremity swelling arose. Based on the two cases, we propose that dual-lumen catheters inserted in the femoral vein and with blood return to the jugular vein could recirculate less than just single catheter placement in femoral or jugular vein. Our work allows us to conclude that blood purification therapy with dual-cannula in jugular-femoral venous may be an effective and feasible strategy for patients with acute superior or inferior vena cava "obstruction".
Acute kidney injury (AKI) is defined as an abrupt decline in kidney function and is assessed based on the glomerular filtration rate [7]. Acute kidney injury in critically ill patients is associated with high morbidity and mortality. Over the past decades, in most critically ill patients with severe acute kidney injury (AKI) and acute liver failure, continuous renal replacement therapy (CRRT) and intermittent hemodialysis has developed into major treatment therapy. Venous double-lumen dialysis catheters in an internal jugular vein or femoral vein are introduced as vascular access in CRRT [8]. However, the use of double-lumen catheters in either jugular or femoral vein may increase the recirculation in critically ill patients with vena cava reflux disorder or severe disconnection. Recirculation consists of having some newly dialyzed blood flowing into the same RRT circuit. It occurs when the input lumen extracts the dialyzed blood from the outflow lumen [9]. Access recirculation remains to be an underrecognized phenomenon in dialysis. For patients with acute vena cava disconnection or severe obstruction, the pressure from the outflow segment may diminish the effective overall dialysis dose. In this setting, CRRT partially loses it efficiency. To improve the circulation status and minimize recirculation, cannulation in two separated insertion sites via femoral vein and jugular vein was used. This multistage draining cannula strategy enables an adequate dialysis dose with a relative low recirculation rate. This modality can act as an extracorporeal bypass with less recirculation and more stable hemodynamics for these patients. Cost can also be reduced by reducing the need for blood sampling and laboratory analysis and ensuring the hemodialysis adequacy. Moreover, such modality can provide the patients with enough time to establish collateral circulation. A prospective controlled study with a large sample size is initiated to explore the exact impact of the blood purification treatment on circulation status, inflammatory response and outcome for such patients and to identify indications for such treatment in patients with AKI. (NCT05510713). Data availability All data, models, and code generated or used during the study appear in the submitted article.

Conflict of interest
The authors declare that they have no competing interests.

Ethics Approval and Consent to Participate
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