- Email: [email protected]
ECMO retrieval in NSW and beyond
Current Anaesthesia & Critical Care 21 (2010) 282e286
Contents lists available at ScienceDirect
Current Anaesthesia & Critical Care journal homepage: www.elsevier.com/locate/cacc
POINTS OF VIEW: MEDICAL TRANSFER
ECMO retrieval in NSW and beyond C. Jones a, *, C. Hommers b, B. Burns b, P. Forrest c a
CareFlight (NSW) Limited, 4 Barden St, Northmead, Sydney, NSW 2145, Australia Greater Sydney Area eHelicopter Emergency Medical Service (GSA-HEMS), Australia c Royal Prince Alfred Hospital (RPAH) Sydney, Australia b
s u m m a r y Keywords: Extracorporeal membrane oxygenation ECMO retrieval
This article discusses the background, logistics and safety of ECMO retrieval in New South Wales, Australia. We look at the experiences of a well established, high volume medical retrieval service and the challenges presented during the recent H1N1 swine flu pandemic. In outlining the referral and retrieval process utilised in NSW we hope that other retrieval services can gain from our experience. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction Extracorporeal membrane oxygenation (ECMO) is a modification of cardiopulmonary bypass technology used to support potentially reversible, life-threatening forms of acute respiratory or cardiac failure which are unresponsive to conventional therapy. Despite descriptions of ECMO use as early as the mid 1970s, evidence of benefit had until recently, been limited to acute respiratory and cardiac failure in neonates. However, the persisting high mortality and morbidity of adults with acute respiratory distress syndrome (ARDS) as well as developments in perfusion technology have continued to generate interest in ECMO as a meaningful therapeutic modality in these settings. In a recent Australasian report, adults with severe H1N1 pneumonia who were treated with ECMO had a 78% survival rate, which is the highest reported adult survival rate in the literature to date.1 2. Background NSW has challenging demographic and geographical considerations for a medical retrieval service. It covers 809,444 km2 (which is roughly three times the size of UK) but has a population of only 6.1 million, 4 million of whom live in the greater Sydney area. The Aeromedical and Medical Retrieval Service (AMRS) was established to provide central coordination of all hospital transfers within NSW by road, rotary wing or fixed wing. Greater Sydney Area-Helicopter Emergency Medical Service (GSA-HEMS) is one arm of AMRS conducting both road and rotary wing transfers and
* Corresponding author. Tel.: þ61 (0)7899894389. E-mail address: [email protected] (C. Jones). 0953-7112/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.cacc.2010.07.004
operates a doctor/paramedic medical crew. The service performs on average 2500 retrievals annually, 70% are inter-hospital and 30% are pre-hospital. Prior to 2009, GSA-HEMS retrieved in total 7 patients on ECMO within NSW, all by road. However, this service was unfunded and provided on an ad-hoc basis. With small numbers it was difficult to adequately train up large numbers of retrieval doctors and transfers were therefore only undertaken by experienced senior retrieval doctors. As part of the 2008/09 adult intensive care services funding enhancement, The NSW Department of Health agreed to support the NSW ECMO medical retrieval strategy, with capital and recurrent funding for up to 10 ECMO retrievals per year. The strategy included the promulgation of indications for ECMO referral (Fig. 1) which were formulated by an expert clinical group. The NSW ECMO Retrieval Service was formally established in May 2009. The service is provided by the GSA-HEMS, Royal Prince Alfred Hospital (RPAH) and St Vincent’s Hospital (SVH) in Sydney. These hospitals are the designated destination hospitals (out of 7 tertiary ICUs that are able to provide ECMO services). Retrievals are coordinated through AMRS and are performed by dedicated ECMO retrieval teams. The NSW ECMO Retrieval Service was introduced one month prior to the onset of the H1N1 Influenza A pandemic in Australia and New Zealand, which during the winter of 2009 placed huge demands upon the retrieval, ambulance and ICU services.3 Between June 1st to August 31st 722 patients with confirmed infection were admitted to ICU in NSW, 456 required mechanical ventilation and 24 received ECMO. Of these patients, 19 patients were retrieved on ECMO. (Median age 34, IQR 26-42, male patients 50%). In total, during 2009, 31 ECMO retrievals for all indications were performed in NSW by GSA-HEMS and CareFlight Ltd (a private, not for profit company providing fixed wing medical retrieval and also
C. Jones et al. / Current Anaesthesia & Critical Care 21 (2010) 282e286
283
Fig. 1. The Indications for ECMO referral in NSW.
doctors for GSA-HEMS). Transportation was by a combination of road, rotary and fixed wing (including 3 international retrievals from New Caledonia).11 In common with other authors 4,5 we found that the transport of adults patients on ECMO was safe, despite a few potentially serious retrieval related complications (including one pump battery failure requiring manual pump operation e see Fig. 2, one case of air entrainment into the circuit and one patient who became hypothermic at 32.2 C). 3. ECMO ECMO is a modified heart-lung bypass circuit used to support life-threatening acute respiratory or cardiac failure. In these cases, it is usually used in venovenous (VV) or venoarterial (VA) configurations via the femoral vessels. VV ECMO is used for respiratory failure; VA ECMO is used if cardiac support is also required. Despite a 30 year history and an established role in neonates, the use of ECMO in adults has been controversial. Early randomised trials failed to demonstrate a survival benefit and the highly specialised
and expensive nature of ECMO have limited expertise.12 However, adult survival rates have been improving, which may be due to improvements in ECMO technology. The most important of these advances include polymethylpentene (PMP) oxygenators,6,7 centrifugal pumps8 and surface- modified circuit components that together increase the durability of the circuits (to weeks instead of days), reduce haemolysis, cause less activation of the systemic inflammatory response and decrease the requirement for anticoagulation to prevent circuit thrombus formation.9,10 Patients who require ECMO support are often too unstable to transfer by conventional means, particularly when distances are long and travel times/delays are protracted. In the recently published CESAR trial 180 patients with severe ARDS were randomised to receive ECMO at Glenfield Hospital (UK) or conventional treatment at a participating tertiary care centre.2 They demonstrated a 16% survival benefit without severe disability in the ECMO referral group (63% vs. 47%). Of note, all patients were transported conventionally. Five patients that had been randomised to the ECMO group died before they could receive it (3 died before
284
C. Jones et al. / Current Anaesthesia & Critical Care 21 (2010) 282e286
Fig. 2. The manual hand pump.
transport, 2 in transit). It is therefore possible that the survival rate in the ECMO group may have been higher if ECMO had been established at the referring hospital. 4. ECMO referral and retrieval process The NSW Indications for ECMO Referral were promulgated throughout all the ICUs in the State by the Department of Health in April 2009. The referring hospital referred directly to the destination hospital (SVH or RPAH) or via the AMRS. A conference call was set-up between the referring clinician, on-call consultant intensivist at RPAH or SVH and the on-call AMRS consultant. RPAH and SVH alternate ECMO on-call on a weekly basis. Once the patient was
confirmed as meeting criteria for ECMO, the AMRS liased with the retrieval team and the ECMO team via teleconference. The retrieval team consisted of an experienced senior retrieval doctor and flight paramedic who would be told the clinical information, timings of insertion of ECMO and retrieval teams, plus modality of transport. The ECMO team consisted of a cardiothoracic surgeon, a medical perfusionist (cardiac anaesthetist) þ/ a clinical perfusionist from the receiving hospital. The flight crew (rotary and fixed wing) would also be informed at the earliest opportunity to enable aircraft configuration, crew resource management and flight planning. All of the logistics of the retrieval were coordinated centrally by the state-wide AMRS. The ECMO team (with necessary equipment) are transported first to the referring hospital by either road ambulance or fixed wing charter flight, depending on the distance involved. They established the patient on ECMO prior to the arrival of the retrieval team. The arrival of the retrieval team was timed to coincide with the estimated establishment of ECMO. The mission as a whole can often be protracted and so fatigue must be factored into the planning of the job. All patients were cannulated peripherally at the ICU bedside (percutaneous or cut-down) after a bolus of unfractionated heparin (5000 U). Anticoagulation was maintained with Heparin infusions and monitored using Activated Clotting Times (150e180 s). A portable i-stat machine (Abbott Laboritories IL, USA) was used to monitor ACT’s. Access to the IVC/SVC was established via the femoral vein or right internal jugular vein; and oxygenated blood returned to either right atrium (via the femoral vein (VV)) or to the femoral artery (VA). Echocardiography was used in all patients (TOE when available, otherwise TTE) to determine the mode of ECMO employed and to assist with cannula placement (radiographic imaging was not performed). VV ECMO was used for all respiratory indications, unless the patient also had severe left ventricular dysfunction (VA was used in a total of 3 patients). All cannulae and tubing are heparin-bonded. Medtronic cannula (Medtronic Perfusion Systems USA) were used in all but one case, (femoral access lines 19e25F, femoral return lines 17e23F, RIJ
Fig. 3. The centrifugal pump and oxygenator attached to the stretcher bridge system. Note this system includes a monitor, ventilator and 3 infusion pumps.
C. Jones et al. / Current Anaesthesia & Critical Care 21 (2010) 282e286
285
Fig. 4. Patient loaded in MPV. Note mobile stand attached to floor of MPV, supporting ECMO circuit, console and its own back up oxygen supply.
access line 19e23F, one patient had an Avalon double lumen 31F cannula in RIJ). There were no cannula insertion related complications reported. A Jostra Rotaflow centrifugal pump and Maquet Quadrox D (polymethylpentene) oxygenator (Maquet Cardiopulmonary AG, Germany) were used in all cases. These were attached to the stretcher bridge system (see photo 2). The service has recently upgraded to a Maquet CARDIOHELP portable ECMO device. This will come on-line in July 2010. During movement of the
patient, the oxygenator and pump were secured to a mobile stand at the side foot end of the stretcher. Oxygen is supplied to the oxygenator via a rotameter. The ECMO pump has an internal battery, which if properly maintained and charged can power the pump for about 90 min (Fig. 3). Inside the vehicle, the ECMO device and retrieval bridge are connected to AC power inverters. A ‘protective’ lung ventilation strategy was continued throughout the retrieval process (low tidal volume, low fraction inspired
Fig. 5. Position of ECMO console strapped to the floor of the helicopter, between seats for the perfusionist and retrieval doctor.
286
C. Jones et al. / Current Anaesthesia & Critical Care 21 (2010) 282e286
oxygen, and high PEEP), with inspired oxygen and minute ventilation titrated down to an acceptable SaO2. Once the patient has been stabilised on ECMO, the overall clinical responsibility falls jointly to the retrieval doctor and the medical perfusionist, who assumes management and responsibility of the ECMO equipment; while the paramedic supervises the logistical movement of the patient throughout the retrieval process. The surgeon and remaining consumables are then transferred back to Sydney separately from the rest of the team following ECMO insertion. 5. Retrieval platforms 5.1. Road ASNSW has five multi-purpose vehicles (MPV) in different parts of NSW at its disposal. These vehicles were designed and built primarily for the transportation of bariatric patients. They have a large custom body mounted on the chassis of a Mercedes Sprinter vehicle. It has a specialised electrically operated “Megalift” stretcher (DHS Emergency, NSW) which has a safe working load of up to 400 kg. The MPVs have sufficient power for the ECMO pump, but not for the portable ECMO heater as well. Therefore it is vital to minimise heat-loss during transfer and the use of Space-blankets þ/ forced air warmers should be considered. A transfer bridge was developed to secure all of the ECMO components to the stretcher during loading. The patient is loaded into the rear of the vehicle head first, the ECMO console is then removed from the transfer bridge and fixed to the floor with tiedowns to the Douglas tracking (see Fig. 3). The retrieval doctor is positioned at the patient’s head, with the perfusionist at the patient’s foot (providing access to the ECMO equipment and to the manual pump) (Fig. 2). 5.2. Rotary wing The Augusta Westland 139 is a twin-turbine, single main rotor helicopter. It underwent an accelerated process to configure the aircraft for aeromedical ECMO retrieval which was completed in August 2009 (after the majority of H1N1 cases had already been transported by road). A standard operating procedure was designed and written by senior medical and paramedical staff at GSA-HEMS. A maximum patient weight of 135 kg is possible for rotary wing transfer on ECMO. Purpose-built brackets were designed for securing the ECMO control box to the floor and the pump and oxygenator to the stretcher bridge (see Figs. 4 and 5). All powered electrical equipment was tested for electro-magnetic interference and all of the above equipment met Civil Aviation Safety Authority (CASA) crash-rating tests approval before becoming operational. The stretcher is positioned East to West and placed feet first. The perfusionist sits next to the ECMO control box and within reach of the motor pump (so again in case of an emergency he can access the manual pump), (Fig. 2). 5.3. Fixed wing These were utilised for the long distance retrievals. There were 4 interstate and 3 international jobs (from New Caledonia, which is
a French protectorate about 3.5 h flight time from Sydney), performed by CareFlight (NSW) Limited. The aircraft used was a chartered Westwind 1124 jet, which has a range of 2500 nautical miles and is pressurised to 8000 feet. This aircraft can only accommodate a 3-person medical team and a patient up to about 110 kgs, depending on body shape. The retrieval team for these cases comprised a senior retrieval doctor, a medical perfusionist and a surgeon, so that all members of the team could be returned in the same aircraft. This would be taken into account prior to departure in the planning phase. The jet contains a Spectrum stretcher base system (Spectrum Aeromed North Dakota), which has an H-size cylinder concealed within in the system along with four 240 V power outlets and two 12 V cigarette lighter outlets (which accommodate the power transformer for the stretcher bridge containing all the monitoring equipment). 6. Conclusion The recent H1N1 virus outbreak put an enormous strain on the NSW retrieval and intensive care services. We were fortunate to have an already established high volume medical retrieval service in place, along with a recently established ECMO retrieval component. ECMO retrievals, with proper planning and coordination were found to be safe, with no major clinical complications. Conflict of interest statement None. References 1. The Australia and New Zealand Extracorporeal Membrane Oxygenation (ANZ ECMO) Influenza Investigators. Extracorporeal membrane oxygenation for 2009 Influenza A (H1N1) acute respiratory distress syndrome. J Am Med Assoc 2009;302(17):1888e95. 2. Peek G, Mugford M, Tiruvoipati R, Wilson A, Allen E, Thalanany M, et al. Efficacy and economic assessment of conventional ventilator support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multi centre randomised control trial. Lancet 2009;374(9698):1351e63. 3. The ANZIC. Influenza investigators. critical care services and 2009 H1N1 influenza in Australia and New Zealand. N Eng J Med 2009;361(7):680e9. 4. Wagner K, Sangolt G, Risnes I, Karlsen H, Nilsen J, Strand T, et al. Transportation of critically ill patients on extracorporeal membrane oxygenation. Perfusion 2008;23:101e6. 5. Foley DS, Pranikoff T, Younger JG, Swaniker F, Hemmila MR, Remenapp RA, et al. A Review of 100 patients transported on extracorporeal life support. ASAIO J 2002;48:612e9. 6. Thiara A, Hoel T, Kristiansen F, Karlon HM, Fiane AE, Svennevig JL. Evaluation of oxygenators and centrifugal pumps for long term pediatric extracorporeal membrane oxygenation. Perfusion 2007;22:323e6. 7. Khoshbin E, Roberts N, Harvey C, Machin D, Killer H, Peek GJ, et al. Polymethylpentene oxygenators have improved gas exchange capability and reduced transfusion requirements in adult extracorporeal membrane oxygenation. ASAIO J 2005;51:281e7. 8. Lawson D, Ing R, Cheifetz IM, Walczak R, Craig D, Schulman S, et al,. Haemolytic characteristics of three commercially available centrifugal blood pumps. 9. Moen O, Hogasen K, Fosse E, Dregelid E, Brockmeier V, Venge P, et al. Attenuation of changes in Leukocyte surface markers and complement activation with heparin-coated cardiopulmonary bypass. Ann Thorac Surg 1997;63: 105e11. 10. Fosse E, Moen O, Johnson E, Semb G, Brockmeier V, Mollnes TE, et al. Reduced complement and granulocyte activation with heparin-coated cardiopulmonary bypass. Ann Thorac Surg 1994;58:472e7. 11. Unpublished data from GSA-HEMS. 2009 12. Zapol WM, Snider MT, Hill JD, Fallat RJ, Bartlett RH, Edmunds LH, et al. Extracorporeal membrane oxygenation in severe acute respiratory failure. A randomized prospective study. JAMA 1979;242:2193e6.
Contents lists available at ScienceDirect
Current Anaesthesia & Critical Care journal homepage: www.elsevier.com/locate/cacc
POINTS OF VIEW: MEDICAL TRANSFER
ECMO retrieval in NSW and beyond C. Jones a, *, C. Hommers b, B. Burns b, P. Forrest c a
CareFlight (NSW) Limited, 4 Barden St, Northmead, Sydney, NSW 2145, Australia Greater Sydney Area eHelicopter Emergency Medical Service (GSA-HEMS), Australia c Royal Prince Alfred Hospital (RPAH) Sydney, Australia b
s u m m a r y Keywords: Extracorporeal membrane oxygenation ECMO retrieval
This article discusses the background, logistics and safety of ECMO retrieval in New South Wales, Australia. We look at the experiences of a well established, high volume medical retrieval service and the challenges presented during the recent H1N1 swine flu pandemic. In outlining the referral and retrieval process utilised in NSW we hope that other retrieval services can gain from our experience. Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction Extracorporeal membrane oxygenation (ECMO) is a modification of cardiopulmonary bypass technology used to support potentially reversible, life-threatening forms of acute respiratory or cardiac failure which are unresponsive to conventional therapy. Despite descriptions of ECMO use as early as the mid 1970s, evidence of benefit had until recently, been limited to acute respiratory and cardiac failure in neonates. However, the persisting high mortality and morbidity of adults with acute respiratory distress syndrome (ARDS) as well as developments in perfusion technology have continued to generate interest in ECMO as a meaningful therapeutic modality in these settings. In a recent Australasian report, adults with severe H1N1 pneumonia who were treated with ECMO had a 78% survival rate, which is the highest reported adult survival rate in the literature to date.1 2. Background NSW has challenging demographic and geographical considerations for a medical retrieval service. It covers 809,444 km2 (which is roughly three times the size of UK) but has a population of only 6.1 million, 4 million of whom live in the greater Sydney area. The Aeromedical and Medical Retrieval Service (AMRS) was established to provide central coordination of all hospital transfers within NSW by road, rotary wing or fixed wing. Greater Sydney Area-Helicopter Emergency Medical Service (GSA-HEMS) is one arm of AMRS conducting both road and rotary wing transfers and
* Corresponding author. Tel.: þ61 (0)7899894389. E-mail address: [email protected] (C. Jones). 0953-7112/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.cacc.2010.07.004
operates a doctor/paramedic medical crew. The service performs on average 2500 retrievals annually, 70% are inter-hospital and 30% are pre-hospital. Prior to 2009, GSA-HEMS retrieved in total 7 patients on ECMO within NSW, all by road. However, this service was unfunded and provided on an ad-hoc basis. With small numbers it was difficult to adequately train up large numbers of retrieval doctors and transfers were therefore only undertaken by experienced senior retrieval doctors. As part of the 2008/09 adult intensive care services funding enhancement, The NSW Department of Health agreed to support the NSW ECMO medical retrieval strategy, with capital and recurrent funding for up to 10 ECMO retrievals per year. The strategy included the promulgation of indications for ECMO referral (Fig. 1) which were formulated by an expert clinical group. The NSW ECMO Retrieval Service was formally established in May 2009. The service is provided by the GSA-HEMS, Royal Prince Alfred Hospital (RPAH) and St Vincent’s Hospital (SVH) in Sydney. These hospitals are the designated destination hospitals (out of 7 tertiary ICUs that are able to provide ECMO services). Retrievals are coordinated through AMRS and are performed by dedicated ECMO retrieval teams. The NSW ECMO Retrieval Service was introduced one month prior to the onset of the H1N1 Influenza A pandemic in Australia and New Zealand, which during the winter of 2009 placed huge demands upon the retrieval, ambulance and ICU services.3 Between June 1st to August 31st 722 patients with confirmed infection were admitted to ICU in NSW, 456 required mechanical ventilation and 24 received ECMO. Of these patients, 19 patients were retrieved on ECMO. (Median age 34, IQR 26-42, male patients 50%). In total, during 2009, 31 ECMO retrievals for all indications were performed in NSW by GSA-HEMS and CareFlight Ltd (a private, not for profit company providing fixed wing medical retrieval and also
C. Jones et al. / Current Anaesthesia & Critical Care 21 (2010) 282e286
283
Fig. 1. The Indications for ECMO referral in NSW.
doctors for GSA-HEMS). Transportation was by a combination of road, rotary and fixed wing (including 3 international retrievals from New Caledonia).11 In common with other authors 4,5 we found that the transport of adults patients on ECMO was safe, despite a few potentially serious retrieval related complications (including one pump battery failure requiring manual pump operation e see Fig. 2, one case of air entrainment into the circuit and one patient who became hypothermic at 32.2 C). 3. ECMO ECMO is a modified heart-lung bypass circuit used to support life-threatening acute respiratory or cardiac failure. In these cases, it is usually used in venovenous (VV) or venoarterial (VA) configurations via the femoral vessels. VV ECMO is used for respiratory failure; VA ECMO is used if cardiac support is also required. Despite a 30 year history and an established role in neonates, the use of ECMO in adults has been controversial. Early randomised trials failed to demonstrate a survival benefit and the highly specialised
and expensive nature of ECMO have limited expertise.12 However, adult survival rates have been improving, which may be due to improvements in ECMO technology. The most important of these advances include polymethylpentene (PMP) oxygenators,6,7 centrifugal pumps8 and surface- modified circuit components that together increase the durability of the circuits (to weeks instead of days), reduce haemolysis, cause less activation of the systemic inflammatory response and decrease the requirement for anticoagulation to prevent circuit thrombus formation.9,10 Patients who require ECMO support are often too unstable to transfer by conventional means, particularly when distances are long and travel times/delays are protracted. In the recently published CESAR trial 180 patients with severe ARDS were randomised to receive ECMO at Glenfield Hospital (UK) or conventional treatment at a participating tertiary care centre.2 They demonstrated a 16% survival benefit without severe disability in the ECMO referral group (63% vs. 47%). Of note, all patients were transported conventionally. Five patients that had been randomised to the ECMO group died before they could receive it (3 died before
284
C. Jones et al. / Current Anaesthesia & Critical Care 21 (2010) 282e286
Fig. 2. The manual hand pump.
transport, 2 in transit). It is therefore possible that the survival rate in the ECMO group may have been higher if ECMO had been established at the referring hospital. 4. ECMO referral and retrieval process The NSW Indications for ECMO Referral were promulgated throughout all the ICUs in the State by the Department of Health in April 2009. The referring hospital referred directly to the destination hospital (SVH or RPAH) or via the AMRS. A conference call was set-up between the referring clinician, on-call consultant intensivist at RPAH or SVH and the on-call AMRS consultant. RPAH and SVH alternate ECMO on-call on a weekly basis. Once the patient was
confirmed as meeting criteria for ECMO, the AMRS liased with the retrieval team and the ECMO team via teleconference. The retrieval team consisted of an experienced senior retrieval doctor and flight paramedic who would be told the clinical information, timings of insertion of ECMO and retrieval teams, plus modality of transport. The ECMO team consisted of a cardiothoracic surgeon, a medical perfusionist (cardiac anaesthetist) þ/ a clinical perfusionist from the receiving hospital. The flight crew (rotary and fixed wing) would also be informed at the earliest opportunity to enable aircraft configuration, crew resource management and flight planning. All of the logistics of the retrieval were coordinated centrally by the state-wide AMRS. The ECMO team (with necessary equipment) are transported first to the referring hospital by either road ambulance or fixed wing charter flight, depending on the distance involved. They established the patient on ECMO prior to the arrival of the retrieval team. The arrival of the retrieval team was timed to coincide with the estimated establishment of ECMO. The mission as a whole can often be protracted and so fatigue must be factored into the planning of the job. All patients were cannulated peripherally at the ICU bedside (percutaneous or cut-down) after a bolus of unfractionated heparin (5000 U). Anticoagulation was maintained with Heparin infusions and monitored using Activated Clotting Times (150e180 s). A portable i-stat machine (Abbott Laboritories IL, USA) was used to monitor ACT’s. Access to the IVC/SVC was established via the femoral vein or right internal jugular vein; and oxygenated blood returned to either right atrium (via the femoral vein (VV)) or to the femoral artery (VA). Echocardiography was used in all patients (TOE when available, otherwise TTE) to determine the mode of ECMO employed and to assist with cannula placement (radiographic imaging was not performed). VV ECMO was used for all respiratory indications, unless the patient also had severe left ventricular dysfunction (VA was used in a total of 3 patients). All cannulae and tubing are heparin-bonded. Medtronic cannula (Medtronic Perfusion Systems USA) were used in all but one case, (femoral access lines 19e25F, femoral return lines 17e23F, RIJ
Fig. 3. The centrifugal pump and oxygenator attached to the stretcher bridge system. Note this system includes a monitor, ventilator and 3 infusion pumps.
C. Jones et al. / Current Anaesthesia & Critical Care 21 (2010) 282e286
285
Fig. 4. Patient loaded in MPV. Note mobile stand attached to floor of MPV, supporting ECMO circuit, console and its own back up oxygen supply.
access line 19e23F, one patient had an Avalon double lumen 31F cannula in RIJ). There were no cannula insertion related complications reported. A Jostra Rotaflow centrifugal pump and Maquet Quadrox D (polymethylpentene) oxygenator (Maquet Cardiopulmonary AG, Germany) were used in all cases. These were attached to the stretcher bridge system (see photo 2). The service has recently upgraded to a Maquet CARDIOHELP portable ECMO device. This will come on-line in July 2010. During movement of the
patient, the oxygenator and pump were secured to a mobile stand at the side foot end of the stretcher. Oxygen is supplied to the oxygenator via a rotameter. The ECMO pump has an internal battery, which if properly maintained and charged can power the pump for about 90 min (Fig. 3). Inside the vehicle, the ECMO device and retrieval bridge are connected to AC power inverters. A ‘protective’ lung ventilation strategy was continued throughout the retrieval process (low tidal volume, low fraction inspired
Fig. 5. Position of ECMO console strapped to the floor of the helicopter, between seats for the perfusionist and retrieval doctor.
286
C. Jones et al. / Current Anaesthesia & Critical Care 21 (2010) 282e286
oxygen, and high PEEP), with inspired oxygen and minute ventilation titrated down to an acceptable SaO2. Once the patient has been stabilised on ECMO, the overall clinical responsibility falls jointly to the retrieval doctor and the medical perfusionist, who assumes management and responsibility of the ECMO equipment; while the paramedic supervises the logistical movement of the patient throughout the retrieval process. The surgeon and remaining consumables are then transferred back to Sydney separately from the rest of the team following ECMO insertion. 5. Retrieval platforms 5.1. Road ASNSW has five multi-purpose vehicles (MPV) in different parts of NSW at its disposal. These vehicles were designed and built primarily for the transportation of bariatric patients. They have a large custom body mounted on the chassis of a Mercedes Sprinter vehicle. It has a specialised electrically operated “Megalift” stretcher (DHS Emergency, NSW) which has a safe working load of up to 400 kg. The MPVs have sufficient power for the ECMO pump, but not for the portable ECMO heater as well. Therefore it is vital to minimise heat-loss during transfer and the use of Space-blankets þ/ forced air warmers should be considered. A transfer bridge was developed to secure all of the ECMO components to the stretcher during loading. The patient is loaded into the rear of the vehicle head first, the ECMO console is then removed from the transfer bridge and fixed to the floor with tiedowns to the Douglas tracking (see Fig. 3). The retrieval doctor is positioned at the patient’s head, with the perfusionist at the patient’s foot (providing access to the ECMO equipment and to the manual pump) (Fig. 2). 5.2. Rotary wing The Augusta Westland 139 is a twin-turbine, single main rotor helicopter. It underwent an accelerated process to configure the aircraft for aeromedical ECMO retrieval which was completed in August 2009 (after the majority of H1N1 cases had already been transported by road). A standard operating procedure was designed and written by senior medical and paramedical staff at GSA-HEMS. A maximum patient weight of 135 kg is possible for rotary wing transfer on ECMO. Purpose-built brackets were designed for securing the ECMO control box to the floor and the pump and oxygenator to the stretcher bridge (see Figs. 4 and 5). All powered electrical equipment was tested for electro-magnetic interference and all of the above equipment met Civil Aviation Safety Authority (CASA) crash-rating tests approval before becoming operational. The stretcher is positioned East to West and placed feet first. The perfusionist sits next to the ECMO control box and within reach of the motor pump (so again in case of an emergency he can access the manual pump), (Fig. 2). 5.3. Fixed wing These were utilised for the long distance retrievals. There were 4 interstate and 3 international jobs (from New Caledonia, which is
a French protectorate about 3.5 h flight time from Sydney), performed by CareFlight (NSW) Limited. The aircraft used was a chartered Westwind 1124 jet, which has a range of 2500 nautical miles and is pressurised to 8000 feet. This aircraft can only accommodate a 3-person medical team and a patient up to about 110 kgs, depending on body shape. The retrieval team for these cases comprised a senior retrieval doctor, a medical perfusionist and a surgeon, so that all members of the team could be returned in the same aircraft. This would be taken into account prior to departure in the planning phase. The jet contains a Spectrum stretcher base system (Spectrum Aeromed North Dakota), which has an H-size cylinder concealed within in the system along with four 240 V power outlets and two 12 V cigarette lighter outlets (which accommodate the power transformer for the stretcher bridge containing all the monitoring equipment). 6. Conclusion The recent H1N1 virus outbreak put an enormous strain on the NSW retrieval and intensive care services. We were fortunate to have an already established high volume medical retrieval service in place, along with a recently established ECMO retrieval component. ECMO retrievals, with proper planning and coordination were found to be safe, with no major clinical complications. Conflict of interest statement None. References 1. The Australia and New Zealand Extracorporeal Membrane Oxygenation (ANZ ECMO) Influenza Investigators. Extracorporeal membrane oxygenation for 2009 Influenza A (H1N1) acute respiratory distress syndrome. J Am Med Assoc 2009;302(17):1888e95. 2. Peek G, Mugford M, Tiruvoipati R, Wilson A, Allen E, Thalanany M, et al. Efficacy and economic assessment of conventional ventilator support versus extracorporeal membrane oxygenation for severe adult respiratory failure (CESAR): a multi centre randomised control trial. Lancet 2009;374(9698):1351e63. 3. The ANZIC. Influenza investigators. critical care services and 2009 H1N1 influenza in Australia and New Zealand. N Eng J Med 2009;361(7):680e9. 4. Wagner K, Sangolt G, Risnes I, Karlsen H, Nilsen J, Strand T, et al. Transportation of critically ill patients on extracorporeal membrane oxygenation. Perfusion 2008;23:101e6. 5. Foley DS, Pranikoff T, Younger JG, Swaniker F, Hemmila MR, Remenapp RA, et al. A Review of 100 patients transported on extracorporeal life support. ASAIO J 2002;48:612e9. 6. Thiara A, Hoel T, Kristiansen F, Karlon HM, Fiane AE, Svennevig JL. Evaluation of oxygenators and centrifugal pumps for long term pediatric extracorporeal membrane oxygenation. Perfusion 2007;22:323e6. 7. Khoshbin E, Roberts N, Harvey C, Machin D, Killer H, Peek GJ, et al. Polymethylpentene oxygenators have improved gas exchange capability and reduced transfusion requirements in adult extracorporeal membrane oxygenation. ASAIO J 2005;51:281e7. 8. Lawson D, Ing R, Cheifetz IM, Walczak R, Craig D, Schulman S, et al,. Haemolytic characteristics of three commercially available centrifugal blood pumps. 9. Moen O, Hogasen K, Fosse E, Dregelid E, Brockmeier V, Venge P, et al. Attenuation of changes in Leukocyte surface markers and complement activation with heparin-coated cardiopulmonary bypass. Ann Thorac Surg 1997;63: 105e11. 10. Fosse E, Moen O, Johnson E, Semb G, Brockmeier V, Mollnes TE, et al. Reduced complement and granulocyte activation with heparin-coated cardiopulmonary bypass. Ann Thorac Surg 1994;58:472e7. 11. Unpublished data from GSA-HEMS. 2009 12. Zapol WM, Snider MT, Hill JD, Fallat RJ, Bartlett RH, Edmunds LH, et al. Extracorporeal membrane oxygenation in severe acute respiratory failure. A randomized prospective study. JAMA 1979;242:2193e6.