**3.4 Management of advanced limb ischemia**

Fasciotomy is a decompression manoeuvre performed on the limb with acute compartment syndrome, a surgical emergency. Release of pressure allows reperfusion of the ischemic muscles potentially avoiding amputation. A recent metanalysis consisting 1886 patients found 10% incidence of compartment syndrome requiring fasciotomy [13].

**Figure 5.** *Protocol for management of limb ischemia.*

**180**

*ipsilateral* venous cannula.

**3.3 Change of cannulation site**

*Advances in Extracorporeal Membrane Oxygenation - Volume 3*

any impact on the patient survival [35].

15.6% and 15.4 vs. 6.25%, respectively) [11].

prophylactic DPC are among others: failed percutaneous insertion, atherosclerotic plaque palpated in open cut-down and need to return to the intensive care unit for patient stabilisation. In a metanalysis reviewing 22 retrospective studies comparing peripheral ECLS with or without DPC, the presence of a DPC was associated with at least a 15.7% absolute reduction in the incidence of limb ischemia; although without

Several cannulas from an introducer sheath up to a paediatric arterial cannula are recommended in the literature for this purpose. An ideal is the one that is resistant to bending and thrombosis and offering a least resistance to flow. We found the incidences of limb ischemia and limb ischemia requiring surgical intervention were significantly higher for the introducer sheath compared with the 10–12F Bio-Medicus® paediatric seldinger cannula utilised for distal limb perfusion (30.6 vs.

To introduce the DPC percutaneously, the superficial femoral artery may be visualised distal to the systemic cannula via Ultrasound. If this is not possible, a cut-down insertion should be performed. If introduced bedside, especially percuta-

Any ECLS circuit exposes blood to non-biological surfaces and is in itself throm-

Due to the discrepancy in size of the aorta and distal superficial femoral artery as well as resistance between the systemic cannula and the DPC, there is a significant discrepancy in the flow rate between them, sometimes resulting in very little or almost no flow through the for DPC. In these cases, a gate clamp on the systemic arm can be helpful; however, it may cause flow turbulence, is potentially thrombo-

Alternatively, and already mentioned above, Epoprostenol, a potent vasodilator, which is established in the treatment of peripheral vascular disease, can be delivered directly into the limb via DPC side-port in order to induce peripheral vasodilatation and increase perfusion. Some paediatric aortic cannulas have a sideport that can be readily used for this purpose [10]. Otherwise, a 3/8–3/8″ connector with a side-port can be inserted into the arm feeding the DPC. In some patients this may result in an increased requirement of vasopressors to maintain central arterial pressure. As a word of caution, selective infusion of vasodilators may also result in hyper-perfusion and clinically relevant oedema, especially in presence of an

Peripheral access for ECLS seek mainly due to urgency or bedside scenario is converted to central access once patient is stabilised or develops complication due to peripheral cannulation. One of the strategies in suspected or established limb involves shifting the arterial cannulation site followed by embolectomy and, if necessary, repair of the vessel. In many cases this may be the ascending aorta, as this offers

bogenic. Therefore, adequate anticoagulation, usually achieved by continuous intravenous delivery of unfractionated heparin is essential to prevent complications such as thrombus formation and clotting of the circuit and stroke, limb and bowel ischemia. Conventionally heparin is delivered via a central venous catheter. As the small arteries of the distal limb are specifically at risk of micro-thrombotic clotting complications a targeted delivery of anticoagulants may offer a strategy to prevent distal ischemia. Continuous heparin delivery in the ECLS circuit before oxygenator

at beginning of ECLS should be considered in any institutional protocol.

genic and increases driving pressure in the system.

neously, the position of the DPC should be confirmed via x-ray.

**3.2 Continuous infusion of anticoagulants and vasodilator drugs**

 Several authors confirm that the procedure is effective provided it is performed as soon as the diagnosis of compartment syndrome is established. It can be performed bedside under local anaesthesia [36, 37]. Four chamber fasciotomies essentially involve decompression of anterior and posterior compartment of the thigh and anterolateral and posteromedial compartments of lower leg. Primary closure of these wounds can be performed following explantation of ECLS and decrease of limb swelling.

A last and unfortunate resort in the management of advanced limb ischemia to save a life is to give up a limb. Irreversible ischemic damage to skin and muscles causes rhabdomyolysis, acute kidney injury, and metabolic acidosis. In such cases, amputation of the limb remains the only option to save the patient's life. Contemporary retrospective observational studies report incidence of lower limb amputation in patients supported with ECLS between 1 to 10% [11, 13, 15, 20, 21, 38]. However, some prospective studies with utilisation of newer technology and ideas such as NIRS for early detection of ischemia and distal arterial pressure based or pre-emptive introduction of DPC reported no amputations [23, 24, 31]. However, apart from the obvious benefit of these newer techniques, patients in studies focusing on limb ischemia may have received significant additional attention and care to prevent and treat limb ischemia at early stage. This in itself may have had a profound effect, further corroborating that early detection of limb ischemia with expectant monitoring and protocol-based prompt intervention may avoid its catastrophic consequences (**Figure 5**).

### **4. Conclusions**

Care of the cannulated limb with maintenance of adequate perfusion to avoid ischemia is as important as the preservation of vital organ function. Limb ischemia plays a seminal role in the fate of a patient supported on ECLS. Vascular complications, particularly limb ischemia negatively affect survival in patients on ECLS. Expectant continuous monitoring utilising NIRS, if used, a flow monitored distal perfusion cannula and hourly surveys of flow in distal arteries and signs of ischemia are key in timely detection of limb ischemia. A prophylactic distal perfusion cannula should always be used in patients with risk factors for development of limb ischemia and can most likely be avoided in others if a small calibre systemic cannula is used. Acceptance of lower ECLS flow, maintenance of pulsatility and avoidance of vasopressors are additional important elements. Prompt intervention to re-establish adequate blood supply after suspicion of limb ischemia is essential to avoid its catastrophic consequences. The safest method of prophylactic or therapeutic introduction of a distal perfusion cannula remains the open cut-down and exposure. Percutaneously inserted distal perfusion cannulas should be checked for their position by fluoroscopy. Also, change of cannulation site and bridging ECLS to a substantive therapy should be part of any strategy for patients on ECLS. If properly integrated into an institutional protocol and adhered to, these strategies allow for successful treatment of patients in need of extracorporeal life support with low complication and high success rates.

#### **Acknowledgements**

Authors are not funded for preparation of this manuscript. Authors thank Olaf Maunz for helping with manuscript editing.

**183**

**Author details**

United Kingdom

provided the original work is properly cited.

Prashant N. Mohite\* and André R. Simon

\*Address all correspondence to: p.mohite@rbht.nhs.uk

*Isn't Limb as Precious as Life?*

*DOI: http://dx.doi.org/10.5772/intechopen.86391*

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

Royal Brompton and Harefield NHS Foundation Trust, Harefield Hospital,

#### **Conflict of interest**

Authors do not have any conflicts of interest.

*Isn't Limb as Precious as Life? DOI: http://dx.doi.org/10.5772/intechopen.86391*
