Lung Rapid Recovery Procurement Combined with Abdominal Normothermic Regional Perfusion in Controlled Donation after Circulatory Death

Summary

The protocol combines a lung cooling rapid recovery technique with abdominal normothermic regional perfusion for abdominal graft procurement in controlled asystole donors, which is a safe and useful method to expand the donor pool.

Abstract

Controlled donation after circulatory death (cDCD) has contributed to increasing donor numbers all over the world. Experiences published in the last years confirm that the outcomes after lung transplantation from cDCD are similar to those from brain death donors; however, the utilization of lungs from asystole donors remains low. Several reasons may be involved: different legal frameworks among countries and centers with different premortem interventions, inadequate lung donor care before procurement, or even poor experience with cDCD procedures and protocols.

Initially, the rapid recovery technique was commonly employed for the procurement of thoracic and abdominal organs in cDCD, but, in the last decade, abdominal normothermic regional perfusion (ANRP) with extracorporeal membrane oxygenation devices has become a useful method to restore blood flow to abdominal organs, allowing their quality improvement and their functional assessment prior to transplantation. This makes the donation procedure more complex and generates doubts about injury to the grafts due to dual temperature.

The aim of this article is to describe a protocol based on a single center experience with Maastricht III donors combining lung cooling rapid recovery in the thorax and abdominal normothermic regional perfusion. Tips and tricks focused on premortem interventions and lung procurement procedure techniques are explained. This may help to minimize the reluctance among professionals to use this combined technique and encourage other donor centers to use it, despite the increased complexity of the procedure.

Introduction

Donation after circulatory death (DCD) started in Spain with uncontrolled donors. In 1996, the first national consensus document on DCD was published as a guide for the practice of uncontrolled donation after circulatory death¹ (uDCD), also setting a moratorium on controlled donation after circulatory death (cDCD). In 2012, a new consensus emerged establishing the basis and the legislative framework for the practice of both uDCD and cDCD². Currently, Spain is one of the most active countries in DCD, reaching the highest rate of donors after circulatory death in the world³. This type of donor represented nearly 35% of the total donors in 2021 in the country, with a marked decrease in uDCD and donors being exclusively cDCD⁴.

Organ procurement in cDCD is commonly performed using the super-rapid recovery technique⁵. After the declaration of death and when the non-touch period has elapsed, a rapid sternotomy and laparotomy is performed. The abdominal aorta and pulmonary artery are cannulated and flushed with cold perfusion solutions to preserve the abdominal and thoracic organs, plus topical cooling is conducted before retrieval⁶. In this situation, cDCD is characterized by the unpredictable consequences of warm ischemia, after the withdrawal of life-sustaining therapy. The ischemic damage during this period of agonic hypotension and progressive hypoxia, followed by the non-touch period after cardiac arrest, is further exacerbated by the later period of cold ischemia⁷. This combination of warm and cold ischemia seems to be detrimental, especially to abdominal grafts^8,9,10, generating more reluctance among professionals in the use of these organs from cDCD donors.

To minimize these risks, an in situ preservation model, based on previous experiences from Spanish teams working in uCDC¹¹, has been developed with growing interest. The use of extracorporeal membrane oxygenation (ECMO) systems to restore blood flow after death and before graft recovery can reverse the metabolic deviations resulting from ischemia and restore cellular physiology¹². Abdominal normothermic regional perfusion (ANRP) can improve the quality of ischemic-damaged organs in cDCD¹³. Organ function can be assessed and improved, allowing a better selection of abdominal grafts for transplantation.

Recent international multicenter experiences provide evidence that ANRP versus the rapid recovery (RR) technique helps overcome traditional limitations in cDCD, reducing rates of post-transplant biliary complications, facilitating successful transplantation of older livers, and improving liver graft survival^14,15. In kidneys, it seems to improve short-term outcomes with a lower delayed graft function and higher 1 year graft survival rates¹⁶. With this evidence, ANRP in cDCD has gained advantages over the rapid recovery technique for abdominal graft procurement and is now applied in several European countries and other parts of the world^17,18.

The use of lungs from cDCD donors, however, was promptly adopted worldwide. A lung functional warm ischemic time of up to 60 min does not seem to affect survival¹⁹. In the last decade, several centers and multi-institutional experiences have reported outcomes after lung transplant from cDCD comparable to those from DBD^20,21. The RR technique is the routine method for lung procurement: lungs are cooled topically and removed after being flushed with cold preservation solution²².

The first experiences combining ANRP and RR of lungs in cDCD were reported by two United Kingdom groups^23,24. Years later, a variation of this technique adding premortem interventions was published²⁵. Results present this dual procurement technique as safe and effective for both abdominal and thoracic grafts²⁶. Obviously, the donation procedure becomes more complex. It requires technological and human resources, sufficient organizational capabilities, and has a higher economic cost. All of this may discourage professionals from starting a program. The aim of this study is to present a protocol especially focused on premortem interventions, cannulation, and aortic occlusion balloon placement, with tips and tricks learned from experience, and comment the different technical details to consider during lung retrieval when ARNP is used. At present, in the Center, cDCD donors have become the main source of grafts for thoracic and abdominal transplantation.

Protocol

These interventions are undertaken at the bedside in the intensive care unit (ICU). This protocol follows the guidelines of the University Hospital Marqués de Valdecilla ethics committee and is in accordance with the Spanish legal framework regarding donation procedures. Informed consent was obtained from next of kin for video recording of the procedures for research. cDCD is considered in patients with catastrophic brain damage or a terminal heart or a neurodegenerative disease for whom the decision to withdraw life-sustaining therapy (WSLT) has been made. Exclusion criteria and lung evaluation are the same as with brain death donors (Table 1).

1. Premortem interventions in the donor

1. Heparinization: administer intravenously a bolus of 300-500 UI/kg of heparin to the donor.
2. Cannulation
   NOTE: Cannulation is performed by the cardiovascular surgeon and is a sterile procedure.
   1. Prepare a sterile instrumentation table, with all the equipment necessary (ECMO kit and surgical tools), as well as the electrocautery and suction system.
   2. Prepare a surgical field on the selected groin with disinfectant solution and sterile drapes.
   3. Make an 8-10 cm longitudinal incision with a no. 23 blade, controlling bleeding with electrocautery and Liga clips. Separate the wound edges with a retractor and proceed with dissection to expose the femoral artery and vein. Embrace both vessels with vessel loops for bleeding control.
   4. Select the appropriate cannula diameters according to the vessel sizes and large enough to provide a sufficient flow for organ perfusion and to prevent low-flow problems (usually 21 French).
   5. Cannulate the femoral vein, introducing first a metal wire as a guide, followed by progressive dilators to finally introduce the cannula. If bleeding is observed, perform a peri cannula 4-0 polypropylene purse string suture for control.
   6. Proceed in the same way with the femoral artery, using in this case a double lumen cannula.
   7. Cut off a 10 cm piece of the ECMO input line. Insert a straight connector with a Luer lock with a three-way stopcock assembled at one end of the piece and connect the other end of the piece to the arterial cannula (Figure 1).
   8. Purge the ECMO lines. Employ an irrigation pear with saline to fill the lines while connecting with cannulas. Connect the output ECMO line to the venous cannula and the input ECMO line to the straight connector with the three-way stopcock previously assembled to the arterial cannula. The three-way stopcock can be used for purging the system (Figure 2).
   9. Keep the ECMO lines clamped. Fix both cannulas to the groin with size 1 silk sutures to avoid displacement during transfer.
   10. Place a monitored pressure line in the femoral artery cannula and in donor's left radial artery.
3. Aortic occlusion balloon placement
   1. Take, as a reference, the distance between the xiphoid process of the donor and the distal end of the arterial cannula and determine the length of the catheter to be inserted to reach the thoracic descending aorta. Set a reference mark in the balloon with a silk suture or a marker.
   2. Introduce a metal wire guide through the free lumen of the femoral artery cannula. Continue with the catheter in the same way, guided by the metal wire, and introduce it until the referenced mark.
   3. Confirm the correct position of the occlusion balloon with portable chest radiography or fluoroscopy (check radiopaque marks of the catheter above the diaphragm).
   4. Check the correct function of the occlusion balloon by filling it with a 50 cc cone syringe with saline just for 4-5 s, confirming that arterial pressure from the femoral cannula disappears while the pressure from the left radial artery is maintained (Figure 3).
   5. When the femoral pulse disappears, record the filling volume as the minimum volume to be used to block the thoracic aorta during ARNP. If flow is detected in the femoral cannula, check again for correct positioning or filling.

2. Withdrawal of life-sustaining therapy (WLST) and declaration of death

1. Transfer the donor connected to the ECMO system to the operation room. Prepare and drape the donor in a sterile fashion.
2. Have the lung and abdominal preservation solutions and lines set and ready. Keep the surgical team scrubbed and sterile and ready in the adjacent operating room.
3. Use a chronometer to register warm ischemic times.
   NOTE: Functional warm ischemic time (FWIT), defined as the time from systolic blood pressure <60 mmHg to ANRP is started for abdominal grafts and the administration of lung preservation solution through the pulmonary artery for lungs (5 min no-touch period is included). Upper limits of 30 min for the liver and pancreas and 60 min for the kidneys and lungs are considered.
4. Allow relatives to be with their loved one during WLST until the declaration of death.
5. Initiate WLST. Extubating is optional according to the relative's wishes. After the declaration of death, lead the relatives out from the surgical area.
6. After the 5 min non-touch period, fill the aortic occlusion balloon with the previously determined minimum volume that ensures descending thoracic aortic block.
7. If pressure from the left radial artery disappears, initiate ANRP. The pressure from the femoral cannula will turn into a continuous non-pulsatile flow provided by the ECMO.
8. If flow in the radial line increases parallel to femoral pressure, stop ANRP and check the correct position and filling or clamp the thoracic aorta after another 5 min non-touch period before restoring ANRP. ANRP is not started until aortic occlusion is fully confirmed.
   ​NOTE: WLST can be performed in the operation room or in the ICU following the preference of relatives and loved ones. If it is performed in the ICU, after the 5 min no-touch period, the balloon is filled and function checked, ARNP is initiated, and the donor is transferred to the operation room where the surgical team is ready to start. If occlusion balloon malfunction is detected, ARNP is stopped until the thoracic aorta is clamped in the operation room.

3. Lung recovery and procurement technique

NOTE: Lung recovery and procurement techniques are performed by the thoracic surgeon and the transplant coordinator (Figure 4).

1. Perform a medium sternotomy: proceed with a median vertical skin incision from the suprasternal notch to the tip of the xiphoid process. Extend the incision to the pectoral fascia and sternal periosteum using electrocautery.
2. Divide the interclavicular ligament and create a plane by finger dissection behind the sternum, both at the level of the suprasternal notch and the xiphoid process. Divide the sternum with an electric saw. Place a sternal retractor and open carefully, releasing the pericardium from the posterior surface of the sternum. Control any bleeding point with electrocautery.
3. At the same time, reintubate and ventilate the donor with 100% oxygen and a positive end-expiratory pressure of 5 cm H₂O.
4. If bronchoscopy was not performed during the donor's ICU stay as a critical patient management maneuver, it can be performed at this point by the second surgeon of the thoracic team. For the bronchoscopy, introduce a flexible bronchoscope through the endotracheal tube and evaluate the anatomy, mucosal appearance, and clear secretions.
5. Open both the pleural cavities by longitudinal incisions in the mediastinal pleura.
6. If there are doubts or problems about an adequate block of the supra-aortic vessels with the occlusion balloon, retract the left lung medially to expose and clamp the thoracic aorta as low as possible under direct vision.
7. Examine the lungs performing visual and palpatory assessment. Inspect for bullae, contusion, atelectasis, pneumonia, and occult tumors. Deliver 1 L of 4 °C saline in both pleural cavities.
8. Reduce the inspired fraction of oxygen to 50%. Open the pericardium with an inverted T incision. Retract laterally the edges of the pericardium with 2-0 silk sutures fixed to the skin with mosquito forceps to expose the heart structures.
9. Place a 4-0 polypropylene purse string suture on the main pulmonary artery below the bifurcation. Perform an arteriotomy with a no. 11 blade and dilate with curved mosquito forceps.
10. Cannulate the pulmonary artery (PA) with a right-angled straight cannula clamped at the end. Connect the pulmonary artery cannula to the irrigation system line, assembling a straight connector with a Luer lock and a three-way stopcock. Connect the irrigation system to the lung preservation solution. Purge the lines.
11. Start flushing 50-60 mL/kg of cold preservation solution in an antegrade fashion. Start flushing 500 µg of prostaglandin diluted in 100 mL of saline at the same time through the three-way stopcock.
12. Open the left atrial appendage or left atrium directly to allow free drainage. If areas of atelectasis are found, recruit them with short inspiratory holds at 25-30 cm H₂O pressure.
13. Once preservation is finished, remove the PA cannula. Announce to the rest of the team the intention to clamp the cava vein and start heart excision.
14. Administer 1-1.2 L of saline solution to the donor before clamping the cava veins to avoid a decrease in pump flow due to the loss of blood venous return from the thorax.
15. Place a cross-clamp in the inferior cava vein, making sure there is enough stump for the liver. Ligate and divide the inferior cava vein with no. 3 silk strand.
16. Tie and divide the superior cava vein caudal to azygous with no. 3 silk strand. Secure the distal stump with a clamp.
17. Leave the clamps remaining in the surgical field, being careful not to remove them by accident, as otherwise ANRP will be compromised. Excise the rest of the heart in a standard fashion.
18. After heart excision, remove the lungs following the same procedure as with brain death donors, as described below.
    1. Divide the inferior pulmonary ligaments, open the posterior pericardium, and expose the esophagus. Free the posterior mediastinal attachments of the lung with blunt dissection, ensuring cautious hemostasis.
    2. Dissect the pulmonary arteries away from the aorta. Isolate the trachea above the carina and pass a TA stapler around.
    3. Inflate the lungs to 50%-60% of tidal volume before withdrawing the endotracheal tube and divide the trachea. Remove any remaining attachment and extract the lung block from the donor.
19. Carefully check the thoracic cavity to detect any bleeding point, especially ligation of the azygos vein and cauterization of the vessels or capillaries from the posterior mediastinum, paratracheal structures, and surrounding tissues. Continuous blood loss may decrease the pump flow.
20. Take the lung block to the back table and proceed with bench surgery. Separate the left and right lungs.
21. With a Foley catheter with an inflated bulb at the tip, perform sequentially, through each pulmonary vein, a retrograde flush with 0.2-0.25 L of cold preservation solution.
22. Pack each lung into a first sterile bag containing cold preservation solution only, surrounded by two other plastic bags, and store in a portable fridge containing ice-cold saline at 4 °C.
23. When an ex vivo lung perfusion system is indicated, follow the steps below for device connections to the pulmonary artery and trachea during lung procurement.
    1. Preserve the main trunk of the pulmonary artery and not only its bifurcation during procurement.
    2. If it is not possible, take a 3-4 cm piece of the aorta to posteriorly suture it to the pulmonary artery bifurcation to replace the pulmonary artery trunk.
    3. Divide the trachea four to five rings above the carina to have enough length for intubation.
    4. Keep and store the lungs in block.

4. Abdominal normothermic regional perfusion

1. Initiate ANRP after filling the aortic occlusion balloon and checking for correct function.
2. Set the following monitoring target points: pump flow = 2-2.5 L/min, continuous pressure of 60-65 mmHg in the femoral artery cannula, temperature = 37 °C, pH = 7.35-7.45, hematocrit >25%.
3. Obtain blood samples from the femoral artery cannula with a 10 mL syringe after starting ANRP and every 30 min for hepatic and renal biochemistry analysis, serum lactate levels, blood arterial gas, and hematocrit values. Maintain ARNP for at least for 90-120 min.
4. Discard the liver if alanine transaminase (ALT) or aspartate transaminase (AST) values are more than four times the upper normal limit during ANRP.

5. Liver and renal recovery

NOTE: Liver and renal recovery are performed by the hepatic surgeon and kidney surgeon, respectively.

1. Perform medium laparotomy: proceed with a median vertical skin incision along the linea alba, from the xiphoid process (join to the previous sternotomy) to the pubis, curving the incision around the umbilicus. Use electrocautery to dissect the subcutaneous fat and superficial fascial layers down to the rectus sheath.
2. Dissect through the anterior and posterior components of the rectus sheath and open the peritoneum to access the peritoneal cavity. Widen the incision by sticking the fingers into the hole created, taking care not to injure the underlying structures. Place retractors to have adequate exposure of the abdomen.
3. Assess the macroscopic quality of the abdominal organs by performing visual and palpatory assessments. A liver biopsy can be taken if any concern is raised, as with brain death donors.
4. If the chemistry values are correct and the macroscopic appearance is normal, validate the organs.
5. Stop the ECMO device. Flush preservation solution for the abdominal organs via the femoral arterial cannula and use the femoral venous cannula for exsanguination.
6. Procure abdominal organs suitable for transplantation in a standard fashion as in DBD^27,28.

Results

We performed a descriptive analysis of 30 lung transplants performed at University Hospital Marqués de Valdecilla with lungs obtained from cDCD donors in the last 2 years, 2020 and 2021. Donor and recipient demographic characteristics, technical data, postoperative outcomes, and short-term results are presented here. These results are presented as absolute numbers and percentages for categorical variables and as measures of central tendency and dispersion for continuous variables. The Kolmogorov-Smirnov test was used to ...

Discussion

Though the use of simultaneous lung cold perfusion with ARNP in cDCD was first published in 2014, very few experiences have been described for this^25,26,29. Moreover, the utilization of cDCD lungs, regardless of the technique used, remains low in most countries.

The critical steps within this protocol are the use of premortem interventions; a specific methodology to ensure coronary and cerebral perfus...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Vial 5 mL Heparin 1000 UI/mL	ROVI		For donor heparinization
ECMO KIT (MATERIALS FOR CANNULATION)
Artery pressure lines	BEXEN MEDICAL	137.15	Artery pressure line por radial artery and femoral cannula
Bandage scissors	SURGIMEDIC	BC-881R	Shear to cut ECMO lines
Bio-medicus Venous cannula 21 Fr (7.0 mm) x 27.5 in (69.9 cm)	MEDTRONIC	96670-121	Venous cannula
Clhorhexidine solution 2%			Disinfectant solution
ECMO device Maquet Rotaflow	Maquet, Rasttat, Germany		ECMO system
Electrocautery handle	DEXTRO	SW12200
EndoReturn Arterial Cannula Kit  21-23F	Edwards Lifesciences	ER21B, ER23B	Arterial cannula with a doble lumen to ECMO connection and to introduce aortic oclussion balloon
Ethicon LigaClip med/short 20 titanium medium	ETHICON	MCS30	Ligaclips for control bleeding during groin dissection
Ethicon LigaClip med/short 20 titanium small	ETHICON	MCS20	Ligaclips for control bleeding during groin dissection
Insertion Kit Bio-medicus 180cm	MEDTRONIC	96551	Insertion Kit for ECMO cannulas, with catheter, metal wire guide and dilators
Irrigation pear	MEDLINE	DYNDE 20125	Pear to be filled with saline and purge ECMO lines at the site of connection with cannulas
Luer cone syringe 50cc	CARDIONATUR	60ML	Syringe filled with saline to fill occlusion balloon
Mersilk no 1, LR-60 CONV , 75 cm	ETHICON	W562H	Silk curved suture for ECMO cannulas fixation
Prolene 4/0	ETHICON	W8355	polypropylene suture for purse string in femoral vessels or vascular suture
Prolene 5/0 , 60 cm	ETHICON	8325	polypropylene suture for vascular suture
Prolene 5/0, 90 cm	ETHICON	8720	polypropylene suture for vascular suture
Reliant Stent Graft Balloon Catheter 12F	Medtronic, Ireland	AB46	Aortic occlusion balloon introduced through femoral artery. It is used as an endoclamp
Scalpel blade no 11	INTRAVEN	150011
Scapel blade no 23	INTRAVEN	150023
Silicone tube	IBERHOSPITEX	0027224-P	Silicone tube to connect suction system
Sofsilk braided silk no 1 strands	COVIDIEN	L-12	Silk strand for ligation or bleeding control
Sofsilk braided silk no 3 strands	COVIDIEN	L-115	Silk strand for ligation or bleeding control
straight connector 3/8"x3/8" with Luer lock	ANDOCOR	04CS0022	Piece to connect arterial cannula with ECMO line and the three way stop-cock for pressure line and blood sampling
Surgical pads pack	TEXPOL	146500
Surgical stapler	COVIDIEN	8886803712	Stapler to close surgical wound
Three-way stopcock	BD CONNECTA	394501	Three way stop-cock to connect farterial cannula with pressure line
Vessel loop large	MEDLINE	VLMAXR	Vascular loop to embrace femoral artery and vein for bleeding control.
Vessel loop small	MEDLINE	VLMINR	Vascular loop to embrace femoral artery and vein for bleeding control.
Yankauer suction terminal 50 V	DEXTROMEDICA	349701	Suction terminal for suction while surgical dissection
SURGICAL TOOLS FOR CANNULATION
Adson retractor 20 cm adn 33 cm
Aortic clamp
Boyd Scissors 18 cm
Dissection forceps without jaws 21 cm
Farabeuf retractor small
Mayo scissors straight 14 cm and 16 cm
Metzembaum scissors 18 cm, 20 cm and 23 cm
Mosquito forceps straigth and curved
Needle holder 18 cm and 23 cm
Russ dissection forceps 15 cm
Scalpel handle no 23 and no 21,  21 cm
Surgical Dissector 23 cm
MATERIALS FOR LUNG PROCUREMENT
10 cc syringe	BD DISCARDIT	309110
Alprostadil 500 mcgs injectable solution	PFIZER		Prostaglandin injected with lung preservation solution
Disposable GIA cartridge Steril 6/Ca	MEDTRONIC	1141634
Disposable GIA stapler 60/3.8 3/Ca	MEDTRONIC	2802122	Stapler for trachea and bronquial division
Foley catheter 18 Ch Folysil	Folysil, Coloplast	AA6118	urinary catheter employed to canulated pulmonary veins for retrograde perfusion
Lung preservation solution Perfadex 1000 mL	Medisan, Uppsala, Sweeden	19811 ( box of 10 units)	Lung preservation solution
Mersilk no 1, LR-60 CONV , 75 cm	ETHICON	W562H	Silk curved suture for pericardium sutures
Paediatric Venous cannula	SORIN GROUP	V132-12	Cannula used for pulmonary artery cannulation
Prolene 4/0	ETHICON	W8355	polypropylene suture for purse string in pulmonary artery
Scalpel blade no 11	INTRAVEN	150011
Sofsilk braided silk no 1 strands	COVIDIEN	L-12	Silk strand to fix arterial cannula with the tourniquet
Sofsilk braided silk no 3 strands	COVIDIEN	L-115	Silk strand for vessel ligation
Sterile bags			To keep and store lungs.
Straigth connector 1,4"/1,4" with luer lock	ANDOCOR	04CS0032	Piece to connect pulmonary artery arterial cannula with preservation line and the three way stop-cock for prostaglandin
Three-way stopcock	BD CONNECTA	394501	Three way stop-cock to connect farterial cannula with pressure line
Uromatic set for irrigation double lead	MEDISAVE	TRC4007N	Irrigation system for lung preservation solution
Uromatic set for irrigation single lead	MEDISAVE	TRC4002	Irrigation system for lung preservation solution
SURGICAL TOOLS FOR LUNG PROCUREMENT
Aortic cross- clamp
Battery-powered surgical saw
Cooley vascular clamp
Dissecting forceps 18 cm and 27,9 cm
Finochietto sternal retractor
Metzembaum scissors 20 cm and 23 cm
Mosquito forceps curved 12,5 cm
Vascular clamps
SURGICAL TOOLS FOR ABDOMINAL ORGAN PROCUREMENT
Adson articulated retractors
Allis forceps 16 cm
Aortic cross-clamps
Boyd scissors 17 cm
Castroviejo needle holder
Cooley Vascular clamps
Crile forceps curved 18 cm
Davis retractor 24.5 cm
DeBakey dissecting forceps 19.7 cm adn 24.1 cm
DeBakey vascular clamps
Dissecting forceps 18 cm and 27.9 cm
Duval forceps 23 cm
Farabeuf retractors
Kidney Trays 300 cc and 500 cc
Kocher forceps straigth 18 cm
Langenbeck retractors 21 cm and 23 cm
Mayo scissors straigth and curved , 17 cm
Mosquito forceps straigth and curved, 12.5 cm
Needle holders 15 cm, 18 cm, 23 cm and 23 cm.
Pean forceps 16 cm
Potts scissors 19cm
Rochester forceps curved 24 cm
Rochester forceps straigth 24 cm
Russ dissection forceps 15 cm and 20 cm
Scalpel handles
Senn-mueller retractor 16 cm