Chapter 4 Transport of the critically ill
All intensive care units (ICUs) are required to move critically ill patients for investigations or procedures that cannot be performed in the ICU. These patients have reduced or absent physiological reserves and even short trips can result in significant adverse events.1,2 These events can be reduced by the use of trained personnel.3,4
In addition, ICU personnel are frequently involved in the stabilisation and transfer of critically ill patients into an ICU,5 and some units may be involved in the transport of patients from the site of a prehospital incident, or between hospitals.6,7 The interhospital transfer could be due to the increasing sophistication of critical care facilities in tertiary hospitals compared with district or rural hospitals, different subspecialty capabilities, local bed shortages3 or, in certain health systems, for insurance or financial reasons. In some cases, the complexity of these interhospital transfers can be further complicated by the need for rapid transport, or the distances involved. All patient movement is associated with an increase in mortality or morbidity, but with an integrated approach using high-level clinical personnel who have the correct equipment and undertake sufficient planning, adverse events can be reduced.3,4,6–8 Regular ambulances or untrained hospital staff should not be expected to manage ICU patients. Compared with specialist transport teams, standard ambulances with junior doctor escorts are associated with more cases of hypotension, acidosis and death.9
The hospital of the future has been described as the critical care hub of a dispersed network of facilities linked by information systems and critical care transport services.10 Critical care transport should be part of a regional intensive care network and adhere to promulgated minimum standards for transport of the critically ill.11,12
INTERHOSPITAL TRANSPORT
Patients are generally moved from the ICU for two reasons:
COMPUTED TOMOGRAPHY SCANNING
The most common diagnostic investigation necessitating transport is computed tomography (CT). On most occasions very little planning and preparation is required for what is almost a routine procedure. The exceptions are patients with head injuries, the administration of nasogastric contrast and the increased aspiration risk in patients with decreased gastric motility. Repeated CT scanning of head-injury patients is common. In those patients with decreased cerebral compliance, movement and changes in body position or PaCO2 can result in marked changes in intracranial pressure (ICP). Prior to transport, EtCO2 should be measured on the transport monitor while the patient remains connected to the ICU ventilator. ICP changes caused by ventilator-induced variations in PaCO2 when switching to the transport ventilator can be reduced by adjusting the minute volume to maintain a stable EtCO2. Adequate sedation will also decrease movement-induced rises in ICP. Ideally, the ICP should be measured on the transport monitor but this is often not possible. Whether a staff member remains in the scanner room or views the patient and monitor from outside depends on patient stability. Radiation exposure is small and is not considered a risk, and depends on where personnel stand in relation to the scanner’s ‘doughnut’, from where the radiation is emitted.
MAGNETIC RESONANCE IMAGING SCANNING
MRI units vary in policy, from prohibiting any equipment in the room to having minimal equipment that is placed as far away from the magnet as possible. The ability of ventilators and infusion pumps to function in the MRI scan room must have been tested prior to any patient being scanned, as some modern transport ventilators have failed in the MRI. Ideally, the equipment should be left outside the room with extensions added to the infusion and ventilator tubing, but this increases the risk of disconnection. There is one reported case of the external part of a pulmonary artery catheter burning through during an MRI scan,16 probably caused by the development of radiofrequency eddy currents. Thermodilution pulmonary artery catheters are probably safe, but although patients with internal defibrillators and permanent pacemakers have been scanned with no consequence, deaths have been reported. Prior discussion with individual MRI units on how ICU patients can be scanned is required.
INTERHOSPITAL TRANSPORT
ORGANISATIONAL ASPECTS
Provision of critical care transport services needs to be a part of regional ICU services. The staffing of critical care transport teams will depend on the workload, with around 300 per year being the threshold for a specific transport roster, depending on transport duration and regulations affecting duty times. Other factors include regional demographics, resources and geography. A team from within that unit, or from another ICU, or an emergency department, or a stand-alone transport service may provide transport of patients to a particular ICU. The merits of each system have been summarised.17 Whatever arrangement is chosen, staff should not be conscripts but selected from those interested in critical care transport, and should be appropriately trained. Use of junior inexperienced staff is associated with increases in preventable mortality and morbidity.18,19 Rostering of teams needs to be appropriate for the workload and take into account the potential for significant overtime hours when urgent requests occur near shift changeovers. If personnel are also allocated to other clinical duties, they need to be readily relieved when required. Equipment should be prechecked and the team should have a practised routine to enable prompt departure.
A coordination centre should be used in systems involving multiple requests and transport teams.
PERSONNEL
The aim of the transport team is at least to maintain but preferably to enhance the level of care. This requires transport teams to have diagnostic and procedural skills to provide the full complement of care for the full range of patients transported. Ideally, the personnel caring for the patient in transit should be equivalent to the ‘front-line’ clinical team at the destination, implying a physician-based team, although transport of well-stabilised patients by non-physician teams has been reported.20
The transport team should be a minimum of two people. For multiple patients a formula of n + 1 personnel for n critical patients has been suggested.21 Multidisciplinary teams of physicians, nurse and/or ambulance officers offer advantages of a wider range of skills and training than a team from any single profession. In certain circumstances, other specialised staff may need to be taken, for example a surgeon or obstetrician.6 It is preferable and safer to add a specialist to the standard team because of the latter’s familiarity with the practicalities of the transport environment. Other desirable attributes in staff include: good teamwork and communication skills; adaptability; reasonable body habitus and physical condition; and no significant visual or auditory impairment or susceptibility to motion sickness. Travel sickness medications such as hyoscine (scopolamine) are of limited value, needing to be taken up to 4 hours pretransport and possibly causing significant side-effects.22
PATIENT SELECTION
Both receiving hospitals and ambulance services need to be alert to possible cases where critical care transport is indicated, but not identified by the referring team. A mechanism that is highly sensitive and specific at identifying patients unsuitable for standard ambulance transport is required. Triage mechanisms and tables to aid in patient selection have been described.23,24
COMMUNICATIONS
A systematic approach is necessary to ensure a smooth response when the need for transport of a critically ill patient is identified. A single toll-free telephone number with conference call capability is the ideal. Facsimile and teleradiology capabilities may also be of value. The one call for assistance should result in the provision of clinical advice if required, the dispatch of a transport team, and finding a bed in an appropriate hospital. Concise, simple clinical advice appropriate for the capabilities of the referring hospital by either the receiving hospital or the transport service is paramount. No matter how fast the transport team’s response, without some interim care the patient with major airway, breathing or circulatory compromise will not survive.6,7 Ongoing advice, including stabilisation and preparation of the patient for transport, may be required prior to the arrival of the transport team. The provision to referring hospitals of a checklist for patient management and preparation for transport may assist.
EQUIPMENT
GENERAL CONSIDERATIONS
Minimum standards for supplies, equipment and monitoring for critical care transport have been developed.10,17 Equipment selection is a compromise between providing for every conceivable scenario and being mobile. The aim should be to have a core set of equipment plus optional items for specific scenarios plus some back-up redundancy for vital supplies and equipment such as oxygen, airway devices and basic circulatory monitoring. A suggested equipment schedule is given in Table 4.1. Meticulous checking of equipment after each use and on a regular basis is essential.
Respiratory equipment |
Intubation kit |
Endotracheal tubes and connectors – adult and paediatric sizes |
Introducers, bougies, Magill forceps |
Laryngoscopes, blades, spare globes and batteries |
Ancillaries: cuff syringe and manometer, clip forceps, ‘gooseneck’ tubing, heat moisture exchanger/filter(s), securing ties, lubricant |
Alternative airways: |
Simple: Guedel and nasopharyngeal |
Supraglottic: laryngeal masks and/or Combitube |
Infraglottic: cricothyrotomy kit and tubes |
Oxygen masks (including high-FiO2 type), tubing, nebulisers |
Suction equipment: |
Main suction system – usually vehicle-mounted |
Spare (portable) suction – hand, O2 or battery-powered |
Suction tubing, handles, catheters and spare reservoir |
Self-inflating hand ventilator, with masks and positive end-expiratory pressure (PEEP) valve |
Portable ventilator with disconnect and overpressure alarms |
Ventilator circuit and spares |
Spirometer and cuff manometer |
Capnometer/capnograph. |
Pleural drainage equipment: |
Intercostal catheters and cannulae |
Surgical insertion kit and sutures (see below) |
Heimlich-type valves and drainage bags |
Main oxygen system (usually vehicle-mounted) of adequate capacity with flowmeters and standard wall outlets |
Portable/reserve oxygen system with flowmeter and standard outlet |
Circulatory equipment |
Defibrillator/monitor/external pacemaker, with leads, electrodes and pads |
Intravenous fluid administration equipment: |
Range of fluids: isotonic crystalloid, dextrose, colloids |
High-flow and metered-flow giving sets |
Intravenous cannulae in range of sizes: peripheral and central/long lines |
Intravenous extension sets, three-way taps and needle-free injection system |
Syringes, needles and drawing-up cannulae |
Skin preparation wipes, intravenous dressings and BandAids |
Pressure infusion bags (for arterial line also) |
Blood pressure-monitoring equipment: |
Arterial cannulae with arterial tubing and transducers |
Invasive and non-invasive (automated) blood pressure monitors |
Aneroid (non-mercury) sphygmomanometer and range of cuffs (preferably also compatible with non-invasive arterial blood pressure) |
Pulse oximeter, with finger and multisite probes |
Syringe/infusion pumps (minimum 2) and appropriate tubing |
Miscellanous equipment |
Urinary catheters and drainage/measurement bag |
Gastric tubes and drainage bag |
Minor surgical kit (for intercostal catheter, central venous lines, cricothyrotomy, etc.): |
Sterile instruments: scalpels, scissors, forceps, needle holders |
Suture material and needles |
Antiseptics, skin preparation packs and dressings |
Sterile gloves (various sizes); drapes ± gowns |
Cervical collars, spinal immobilisation kit, splints |
Pneumatic antishock garment (military antishock trousers (MAST) suit) |
Thermometer (non-mercury) and/or temperature probe/monitor |
Reflective (space) blanket and thermal insulation drapes |
Bandages, tapes, heavy-duty scissors (shears) |
Gloves and eye protection |
Sharps and contaminated waste receptacles |
Pen and folder for paperwork |
Torch ± head light |
Drug/additive labels and marker pen |
Nasal decongestant (for barotitis prophylaxis) |
Pharmacological agents |
Central nervous system drugs: |
Narcotics ± non-narcotic analgesics |
Anxiolytics/sedatives |
Major tranquillisers |
Anticonvulsants |
Intravenous hypnotics/anaesthetic agents |
Antiemetics |
Local anaesthetics |
Cardiovascular drugs: |
Antiarrhythmics |
Anticholinergics |
Inotropes/vasoconstrictors |
Nitrates |
α- and β-blockers; other hypotensives |
Electrolytes and renal agents: |
Sodium bicarbonate |
Calcium (chloride) |
Magnesium |
Antibiotics |
Oxytocics |
Potassium |
Loop diuretics |
Osmotic diuretics |
Endocrine and metabolic agents: |
Glucose (concentrate) ± glucagon |
Insulin |
Steroids |
Other agents: |
Neuromuscular blockers: depolarising and non-depolarising |
Anticholinesterases (neuromuscular block reversal) |
Narcotic and benzodiazepine antagonists |
Bronchodilators |
Antihistamines |
H2-blockers/proton pump inhibitors |
Anticoagulants |
Thrombolytics |
Vitamin K |
Tocolytics |
Diluents (saline and sterile water) |
Additional/optional equipment |
Transvenous temporary pacing kit and pacemaker |
Blood (usually O negative) and/or blood products |
Additonal infusion pumps and associated intravenous sets |
Obstetrics kit |
Additional paediatric equipment (depending on capability of basic kit) |
Antivenene (polyvalent or specific) |
Specific drugs or antagonists |
Transport monitors, infusion pumps and ventilators must work outside the transport vehicle. This requires equipment to be battery-powered and readily portable. Although newer monitors and other devices have rechargeable batteries with improved endurance, problems can still occur. The equipment-checking process includes different charging regimes. Nickel cadmium (NiCad) batteries need to be fully discharged before recharging to decrease memory effect, which reduces endurance, whereas sealed lead–acid or lithium batteries perform best when continually charged between uses.25
Portability can be addressed in two ways. Equipment can be vehicle-mounted but readily detachable to accompany the patient, either as individual devices or more conveniently as a modular unit.26 Alternatively, a mobile intensive care module can be incorporated into the stretcher, either in the base27 or as a ‘stretcher bridge’ straddling the patient.28 Such designs are now widely used and allow the patient and equipment to be assembled into one unit at the referral point; this reduces loading and unloading time, ventilator and other device disconnections, and the risk of leaving equipment behind. Minor disadvantages include the increase in weight (25–30 kg), with corresponding reduction in maximum patient weight, and slight top-heaviness of the stretcher/patient combination.