Multivisceral transplantation (MVTx) have gained acceptance as therapeutic modalities for patients with: intestinal failure with life-threatening complications of parenteral nutrition (PN), rare cases of vascular abdominal catastrophes and some cases of low-grade neoplastic tumors and desmoids involving the mesenteric root. This prolonged procedure, associated with significant blood loss, metabolic abnormalities, temperature fluctuations, fluid and electrolyte shifts, and coagulopathy. Malnutrition, dehydration, reduced physiologic reserves due to long-standing intestinal failure, and liver dysfunction make these challenges more difficult to overcome (3). These pathophysiologic considerations underpin the anesthetic plan for the patients undergoing multi-visceral transplantation (4). In this case series, the anesthetic aspects of five MVT cases at a referral single center were discussed.
In addition to peripheral access, a large-bore introducer should be embedded in the right internal jugular vein for fluid resuscitation, blood products transfusion and vasopressor infusion. Patients presenting for multi-visceral transplantation are critically ill, and long-term parenteral nutrition increases the risk of prior venous thrombosis. Therefore, using bedside ultrasound is recommended to identify the target vein (5). A radial arterial catheterization is suggested for the beat-to-beat evaluation of mean arterial blood pressure, measurement of systolic pressure variations in estimating intravascular volume status, and the continuous evaluation of blood gasses, hemoglobin, and electrolytes (6, 7). During MVT, wide temperature fluctuations secondary to prolonged exposure of the viscera is common, so the maintenance of normothermia is essential, which prevents coagulopathy and cardiac instability followed by hypothermia (5, 8). Accordingly, we measured core body temperature through the esophageal probe and considered pre-warming of resuscitation fluids. Blood glucose (BS) monitoring is necessary in all cases recently had undergone TPN, and supplemental dextrose is required to prevent hypoglycemia following abrupt discontinuation of TPN.
Fluid resuscitation is crucial because of the prolonged operation time, significant blood loss, and excessive third-space losses. Therefore, conservative fluid management and application of a pulse counter cardiac output (PICCO) system are the recommended fluid management strategies to restore intravascular volume (9). In this study, PICCO was used to evaluate pulse pressure variation (PPV) and stroke volume variation (SVV) which predict the preload volume and fluid responsiveness.
Colloid solutions are more effective plasma volume expanders than crystalloids and reduce the severity of bowel edema. Studies suggest that the optimal crystalloid-to-colloid volume ratio is approximately 60:40. A balanced fluid strategy is a well-directed technique to maintain mean arterial pressure (MAP) > 60 mm Hg and target CVP >10-12 mm Hg), it aims to stabilize hemodynamic status and improve organ perfusion (10). To prevent bowel edema, we considered a conservative fluid strategy that maintains the target CVP < 10 mm Hg with the concomitant administration of vasopressor infusions (norepinephrine, vasopressin, and/or epinephrine) if the MAP was < 60 mmHg. It should be noted that the mean ±SD of total volume administration was 15±1 cc/kg/h which were given as normal saline solution 0.9% /albumin 20% (60%/40%).
Some researchers have suggested that Rotational thromboelastometry (ROTEM) can be applied for the evaluation of coagulation status in MTX (6). Using intra-operative ROTEM analysis in our center revealed that the majority of patients were in a ‘hypercoagulable status’ and there was no need for fresh frozen plasma (FFP), cryoprecipitate ,and platelet except the fourth case, whom we transfused FFP, cryoprecipitate ,and platelet to correct microvascular bleeding after massive transfusion.
Bleeding during the MVTx procedure would be either surgical or coagulopathic or both. It might be more severe in patients with adhesions from previous abdominal surgeries, portal hypertension, or portal vein thrombosis (PVT) (11).We had an average of 2600 cc blood loss during these MVTx procedure. To achieve adequate tissue oxygenation, the hemoglobin level should be maintained at the range of 7-10 g/dl. On the other hand, overcorrection of hemoglobin may enhance the risk of vascular graft thrombosis and should be avoided (12). In our study, the average Hb level was 10.62 g/dl and the average transfusion of packed red blood cells was 4±1 bag in the series.
About 47% of patients undergoing small bowel transplants experience post-reperfusion syndrome (PRS) (13). PRS is the largest hemodynamic disorder due to the amount of reperfused organs. It is characterized by marked decreases in MAP, and systemic vascular resistance, as well as moderate increases in pulmonary arterial pressure and central venous pressure. This syndrome may also develop when the mean arterial pressure (MAP) is less than 60 mm Hg or 30% below the pre-unclamping baseline value, lasting for at least 1 min, within 10 min after unclamping (8, 14, 15). The PRS occurred among all these five cases but severe PRS which needed continuous vasopressin and norepinephrine infusion happened in only one case. It is well-documented that several factors contribute to PRS development (i.e., hyperkalemia, acidosis, sudden hypothermia, vasoactive substances like free radicals, endotoxin, inﬂammatory cytokines, and acidotic compounds produced by the graft or intestine) (15) Aortic cross clump and PRS may also contribute to renal injury. Studies suggested that the risk of post-transplant renal failure was 50% in MVTx (16). We did not observe any case of CRRT or dialysis-requiring acute kidney injury. It might be related to maintaining MAP > 60 mmHg and improving kidney perfusion pressure with infusion minimum dose of vasopressor during the clumping and unclamping phase (16, 17).
Indeed, TPN supplement contain potassium, on the other hand, concomitant liver graft reperfusion may enhance the intensity of hyperkalemia. Serial measurements of plasma potassium have suggested to keep the potassium level below 4 mmol/L before un-clumping phase and revascularization (18). Treatment options for hyperkalemia include the simultaneous administration of insulin and hypertonic-glucose, calcium gluconate, insulin, sodium bicarbonate, and diuretics (19-21).
In this study, methylprednisolone was administered simultaneously in the beginning of vascular anastomosis. A Wide range of antibiotics are a part of our center’s protocol to prevent infection and immunosuppression infusion (thymoglobin), but MVTx procedure are associated with considerable risk of immunomodulation and immunosuppression, so patients are more likely to experience a postoperative infection. Recent advances in surgical techniques and immunosuppressive treatments, have increased knowledge about immunologic responses, and critical post-operative services have made MVTx an effective lifesaving intervention for cases having already adopted other treatment interventions.
Considering the limited and retrospective nature of the data herein discussed, there may be some concerns regarding the potential bias or overestimation of management. However, to the best of our knowledge, this is the first study in Iran presenting a series of patients undergoing MVTx and future studies are still recommended to assay other aspects of this technique.