Percutaneous vascular cannulation for ... - SAGE Journals

Int J Artif Organs 2010 ; 33 ( 8): 553- 557

case report

Percutaneous vascular cannulation for extracorporeal life support (ECLS): A modified technique Giacomo Grasselli1, Antonio Pesenti2,1, Roberto Marcolin1, Nicolò Patroniti2,1, Stefano Isgró2,1, Paola Tagliabue1, Alberto Lucchini1, Roberto Fumagalli2,1 1 2

Department of Perioperative Medicine and Intensive Care, San Gerardo Hospital, Monza - Italy Department of Experimental Medicine, University of Milano-Bicocca, Milan - Italy

ABSTRACT Purpose: Vascular access and cannulation are crucial issues to maximize the efficiency of extracorporeal circulation techniques and to preserve patients’ safety. Techniques of cannulation have changed over the years, from surgical cutdown to percutaneous approaches, which are now considered standard practice. We describe an original modified percutaneous cannulation technique developed in our Department and we report our clinical experience and complications observed. Methods: A Seldinger technique utilizing 3 guidewires with passage of a dilator over each guidewire was used. Two concentric pursestring sutures, prepared before cannulation, minimize procedureassociated bleeding. Cannulation is performed under direct fluoroscopic control. Results: From 1997 to 2009, 38 patients (31 VV-ECLS, 7 VA-ECLS) have been cannulated using our technique, resulting in a total of 69 venous cannulations. Average external caliber of venous cannulae was 23 Fr (15-29 Fr). Mean duration of the entire cannulation procedure was 40 minutes (20-60 min). Adverse events occurred in 3 patients. Conclusions: The technique described is safe and feasible and the incidence of procedure-related complications is very low, but it may require longer time to be performed. Key words: Extracorporeal life support (ECLS), Extracorporeal techniques, Percutaneous vessel cannulation Accepted: July 7, 2010

INTRODUCTION Acute respiratory distress syndrome (ARDS) is a form of acute respiratory failure characterized by impairment of pulmonary gas exchange caused by diffuse injury to the alveolar-capillary barrier (1). Mechanical ventilation is a lifesaving maneuver, but it has been demonstrated that an inappropriate ventilatory strategy contributes to worsening and perpetuation of lung damage (known as “ventilatory-induced lung injury”) (2, 3). A seminal study by the ARDS Network cooperative group has shown that a “lung protective ventilation” with low tidal volumes results in a significant decrease of mortality (4). In cases of refrac-

tory hypoxemia and hypercapnia despite optimization of the ventilatory mode and application of rescue strategies (such as recruitment maneuvers, pronation, nitric oxide inhalation), the use of an extracorporeal cardiopulmonary support has been proposed as salvage-therapy. Extracorporeal support technology was developed in the field of cardiac surgery in the 1940s (5) and its successful use in an adult patient with ARDS was first described in 1971 by Hill (6). Since then, different techniques have been described: we will use the term “extracorporeal life support” (ECLS) coined by Bartlett (7) to encompass all the techniques using an artificial lung to support respiratory or cardiac function.

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The concept is apparently very simple: blood is diverted from the patient to an artificial lung for gas exchange (oxygenation and CO2 removal) and then returned into the patient’s circulation once arterialized. The bypass may be veno-arterial (VA), veno-venous (VV) or arterovenous (AV). In the first two cases, a roller or centrifugal pump is needed to drain blood from the patient, whereas in AV bypass the driving force of blood flow is the patient’s arteriovenous pressure gradient (“pumpless extracorporeal interventional lung assist”, iLA) (8). Several technical aspects of extracorporeal techniques are of paramount importance to maximize the efficiency of the system and preserve patient safety. Among these, vascular access and cannulation are crucial. In adults, the femoro-femoral access is the first choice; axillary and subclavian vessels, internal jugular vein and carotid artery are alternative choices. Drainage and return of blood are realized using heparin-coated, spiral-armed cannulae. Cannulae must have a thin wall to minimize resistance to flow and must be available in various diameters. In general, the size of arterial cannulae is 13-21 Fr, whereas venous cannulae are 21-28 Fr in size to allow a blood flow as high as 6 l/min. Techniques of cannulation have changed over the years. Initially, surgical cutdown was required but this approach was time-consuming and frequently flawed by complications. For these reasons, percutaneous techniques have been implemented and are now considered standard practice. In this article, we will describe an original modified procedure developed in our department, aimed at obtaining a safe and uneventful percutaneous vascular access; we will also describe our clinical experience with this technique and the complications observed.

Technique Before puncture of the femoral vein, the diameter of the vessel is measured by ultrasound to select a cannula of appropriate caliber (usually two-thirds of the actual vessel diameter to ensure adequate blood flow around the cannula and avoid leg ischemia). The entire procedure is performed in aseptic conditions and involves the following steps (Fig. 1): 1. an 8 Fr catheter sheath introducer with an hemostasis valve is introduced into the vessel with the usual Seldinger technique; 2. two concentric pursestring sutures are prepared in the 554

subcutaneous tissue around the insertion point of the introducer: these will be used to limit blood loss during the procedure and at the moment of decannulation; 3. two 80 cm and one 150 cm long stainless-steel, jshaped guidewires are passed through the 8 Fr introducer into the vessel; proper insertion of each guidewire is confirmed by direct fluoroscopic control; 4. the 8 Fr introducer is removed while an assistant keeps under tension the internal pursestring suture to avoid excessive blood loss from the insertion site; 5. a vessel dilator is then passed over each guidewire: to obtain proper dilation of the percutaneous tract, the sum of the calibers of the three dilators should approximate the diameter of the cannula chosen for the bypass (e.g., if a 24 Fr cannula is to be inserted, an 8 Fr dilator is passed over each guidewire); 6. to avoid kinking of the guidewire and subsequent exit of a dilator from the vessel, it is important to ensure that the wire moves freely within the dilator during dilation; in any case, entry of each dilator tip into the vessel lumen is confirmed by direct radioscopic control; 7. after dilation is achieved, all dilators and the two short guidewires are removed while an assistant holds the internal pursestring suture to avoid excessive blood loss from the insertion site; at the end of this step only the 150 cm guidewire is left in the vessel; 8. the extracorporeal cannula with its dilator is finally inserted over the guidewire into the vessel, still under direct radioscopic control; 9. after entry into the vessel is confirmed, the dilator and the guidewire are removed and the cannula is advanced into the vessel; 10. the cannula is secured to the skin by appropriate fixation stitches (Fig. 2). In ARDS patients we usually institute a VV femorofemoral bypass which, compared to the femoro-jugular access, carries a higher risk of blood recirculation: for this reason proper positioning of the cannulae is crucial and confirmed by direct fluoroscopy. The tip of the drainage cannula is usually placed at L1-L2 (below the origin of renal veins), while the reimmission cannula is advanced up to the junction between the inferior vena cava and the right atrium (T10-T11). With this approach, blood recirculation (which is calculated at least once daily) is acceptably low (on average 11%).


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Fig. 1 - Panel a) a vascular introducer is placed over a guidewire in a femoral vein; b) two concentric pursestring sutures are realized around the insertion site; c) the inner suture is temporally tightened to minimize bleeding; d) fluoroscopic confirmation of proper insertion of the guidewires; e) a vessel dilator is passed over each guidewire; f) detail of a cannula after fixation. The outer pursestring is left loose for further utilization (i.e., at decannulation).

Our experience From 1997 to 2009, the method described in this article has been used in 38 patients: a VV bypass was used in 31 cases and a VA bypass in 7 cases. In this patient population, a total of 69 venous cannulations were performed using our technique. The average caliber of the venous cannulae was 23 Fr (range 15-29 Fr) and the mean duration of the entire cannulation procedure was 40 minutes (range 20 to 60 min). In these patients, the extracorporeal support lasted on average 25 days (range 0.5 to 139).

No major undesirable events related to the procedure (like vascular laceration or fistolization) were observed. Periprocedural (i.e., within 48 hours) bleeding from the site of insertion of the cannulae was the most common side effect, but it was usually of minor intensity and required RBC transfusion only in 3 subjects. In our patient population, blood was propelled by means of centrifugal pumps. The average extracorporeal blood flow was 2.65 ± 0.9 l/min (range 0.73-4.72). The pressure before and after the artificial lung was monitored: to avoid cavitation and hemolysis, the suctioning (negative) pressure was kept in the safe range of -20 to -30 mmHg.


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Fig. 2 - A schematic representation of the procedure. See text for details.

DISCUSSION Extrathoracic cannulation for extracorporeal cardiopulmonary support was first described by Danielson in 1968 as a salvage method for stabilization of cardiac surgery patients (9). Until 1989, surgical exposure of the vessels was required. The veins needed to be cannulated both distally and proximally and bleeding from surgical sites was a serious complication requiring repeated revisions (10). After few years, the introduction of a double-lumen catheter made it possible to use a single cutdown for drainage and return of blood (10). The next step was cannulation of the femoral veins via the sapheno-saphenous approach, which was associated with reduced risk of bleeding and avoided the need of vein repair at decannulation (10). Finally, in 1988 the use of percutaneous cannulation technique was described and bleeding from cannulation site was almost completely avoided (11, 12). In 1999, Bartlett reported a series of 188 percutaneous cannulations performed in 94 patients placed on venovenous femoro-jugular bypass at the University of Michigan (13). There were 11 unsuccessful cannulation attempts. The complications were rare and consisted of arterial injury requiring operative cutdown and repair (3% 556

of patients) and cannula-site bleeding required pursestring suture reinforcement (6%); one patient died from the perforation of the superior vena cava during cannulation. Recently, Bein reported the use of pumpless femorofemoral AV bypass in 90 ARDS patients; vessels were cannulated percutaneously (8). Complications related to cannulation procedure were: formation of hematoma/aneurysm at insertion site in two patients and diffuse bleeding leading to hemorragic shock during the procedure in one patient. The high incidence of lower limb ischemia after arterial cannulation (10%) was probably related to an excessive size of the arterial cannula and/or to the low dosage of heparin used for anticoagulation. Percutaneous cannulation has the following advantages over surgical cutdown: reduced risk of bleeding, shorter operative time, easier mobilization and nursing of the patient, reduced incidence of infection of the insertion site. Reduction of bleeding episodes is particularly important in these patients, who receive high doses of heparin for complete anticoagulation. It follows that percutaneous cannulation is now considered the method of choice and that the surgical approach should be reserved to the rare cases of failure of the percutaneous procedure. In the present article we describe a modified method of


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percutaneous insertion of extracorporeal cannulae. In our experience, the advantages of this modified procedure compared to the usual Seldinger technique are the following: 1. the use of three guidewires under direct fluoroscopic control reduces the risk of inadvertent kinking of the guidewire with subsequent exit of the dilator from the vessel and laceration of the vein wall; 2. passage of a dilator over each guidewire allows a progressive and gradual dilation of the percutaneous tract and facilitates cannula insertion; 3. when a single dilator is used (classical technique), the surface of contact between the skin and the dilator is equal to the circumference of the transverse section of the dilator; the contemporary use of three smaller dilators allows a significant reduction of this surface and of the resulting friction; 4. preemptive preparation of two concentric pursestring sutures contributes to minimize procedure-associated bleeding; 5. direct radioscopic control of each step further reduces the risk of guidewires/cannula malpositioning with sub-

sequent formation of hematoma or aneurysm at insertion site. The very low incidence of procedure-related complications observed in our patients confirms the feasibility and safety of our method. A potential problem may be the longer time required for cannulation compared to the usual technique: in our experience, the average time required to complete the procedure was 40 minutes, and for this reason the technique is not suitable in situations of real emergency.

Conflict of interest statement: The authors have no conflict of interest or financial support to declare.

Address for correspondence: Giacomo Grasselli, MD Department of Perioperative Medicine and Intensive Care San Gerardo Hospital Via Pergolesi 33 20052 Monza, Italy e-mail: [email protected]

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