Traumatic brain injury (TBI) and cerebral vascular hemorrhage are acute neurological emergencies that require intensive monitoring and immediate life-saving procedures. However, the neurological damage from acute brain injury (ABI) does not only occur just at the moment of impact but evolves over hours and days after the primary injury. Secondary brain injury (SBI) can be caused by ischemia, hypotension, hypoxia, hypercapnia, and cerebral edema. Despite the etiology of the neurological injury, the treatment of ABI focuses on preventing or minimizing the extent of SBI. The SBI can manifest as intracranial hypertension, insufficient cerebral perfusion pressure, and poor cerebral oxygenation. These conditions can lead to greater neurological dysfunction and increased morbidity and mortality (Brain Trauma Foundation et al., 2007).
A study by Papson, Russel, and Taylor (2007) indicated that 68% of unexpected events were associated with transports of critical ill patents. Hypotension and inadequate sedation and paralysis were among of the common causes for the unexpected events. In 8.9% of the transfers, unexpected events such as severe hypotension, respiratory distress requiring intubation, increased intracerebral pressure (ICP), and cardiac arrest occurred. In a study of intrahospital transports of patients with brain injury conducted by Swanson and Mascitelli (2010), the authors reported that more than 50% of the transported comatose patients showed a greater than 5% decrease in brain tissue oxygen and long episodes of brain tissue hypoxemia posttransport. In a prospective study of 50 patients with brain injuries who were transported from the intensive care unit (ICU), adverse effects in 51% of the patients were observed (Andrews, Piper, Dearden, & Miller, 1990). These adverse effects included hypotension, hypertension, hypoxia, and increased intracranial pressure. In addition, Andrew et al. reported that the adverse effects resulted from the transports significantly increased on the patients with high severity scores. The findings of these studies indicate that considerable risks are associated with transportation of patients with ABI.
However, intrahospital transport is deemed necessary when benefits to the patient clearly outweigh the potential risks involved. Thorough resuscitation and stabilization of the patient before transport is the key to avoid complications during the transport. This must be balanced with the need to quickly obtain diagnostic imaging so that treatment to save the patient’s life or prevent further brain injury can be initiated. Rapid detection of differential types of intracranial injury including hemorrhage is important, as life-saving neurosurgical intervention may be required. Typically, early diagnosis prompts early intervention leading to better long-term outcomes.
Patients with ABI frequently require diagnostic or therapeutic procedures in areas located outside of the ICU. Transports can be risky for patients with ABI without proper preparation, execution protocols, and emergency response procedures. The purpose of this article is to review the risks associated with the transportation of critical ill patients out of the ICU and recommend appropriate strategies that can be applied to minimize the risk of SBI.
Strategies for Safe Transport of Patients With SBI
Organizing for a transfer, to ensure appropriate preparation, is necessary. Appropriate equipment, monitoring, and trained staff should be available. Continued reassessment of the patient’s clinical status during transfer is mandatory. Ideally, the level of monitoring and the frequency of measurement of physiological parameters should be the same as it would be in the ICU. Most of the principles of safe transfer are common to all seriously ill patients, but there are some specific features that apply in particular to those with ABI.
Establishment and maintenance of a patent airway is always the first priority for all patients. Some of the most high-risk patients who have not yet shown any indication for intubation require a diagnostic study. These patients could deteriorate during the transport and diagnostic procedure and require an ICU level of care (Kue, Brown, Ness, & Scheulen, 2011). Association of Anesthetists of Great Britain and Ireland (AAGBI, 2006) recommends that patients, who are with a Glasgow Coma Scale (GCS) score of 8 or less and have a significantly deteriorated conscious level, require intubation before transfer. Patients with ABI who are mechanically ventilated should be appropriately sedated and receive adequate pain management to prevent discomfort and anxiety. Agitation in patients with ABI increases the cerebral metabolic rate for oxygen consumption. Increased ICP can negatively affect SBI. Nevertheless, sedation and analgesia should be used more selectively, and amounts given should be titrated to ensure that the lowest effective dose is given in patients with ABI to allow neurological examinations. Propofol and fentanyl are the preferred agents because of their short durations of action and predictable rapid recovery (Uren, Lowell, & Silbergleit, 2009).
As soon as a patient’s airway is secured, care must be given to maintain adequate ventilation. Suctioning to clear the endotracheal tube of secretions before transport is needed to prevent ventilator-associated pneumonia and maintain airway potency (Bercault, Wolf, Runge, Fleury, & Boulain, 2005). Vasoconstriction associated with hyperventilation should be avoided as it can result in decreased cerebral blood flow and precipitate further cerebral ischemia. Guidelines for the management of severe TBI from the Brain Trauma Foundation et al. (2007) recommend that, for most patients, a normocapnia level of 35–40 mm Hg should be maintained. Uren et al. (2009) suggested the use of end-tidal carbon dioxide monitoring and transport ventilators for patients with TBI to allow consistent titratable ventilation to prevent hyperventilation or hypoventilation.
Confirmation of hemodynamic stability before transportation is also critical. Intravenous volume loading should be undertaken with crystalloid or colloid fluids to initially maintain and restore cerebral perfusion, blood pressure, and urine output. Hypovolumic patients tend to tolerate transfer poorly. Thus, the circulating volume needs to be normal or supranormal before transfer. Thorough resuscitation and stabilities must be complete before transfer to avoid adverse events during transport (AAGBI, 2006). Critical checkpoints, including airway, breathing, circulation, and disability as summarized in Table 1, for pretransport assessment should be implemented to warrant a high quality transfer and the best outcome for the transport of ABI patients.
Monitoring During Transport
Monitoring the partial pressure of oxygen and end-tidal carbon dioxide is recommended for ensuring proper oxygenation during transport. A central venous catheter may be useful to optimize filling pressures and for the administration of drugs and fluids during the transfer. Vascular access sites should remain accessible during the transfer (Day, 2010).
For patients with severe ABI with a GCS score range of 3–8, the Brain Trauma Foundation recommended that ICP, cerebral perfusion pressure, and brain tissue partial pressure of oxygen are to be monitored. Elevated ICP is especially a concern for patients with ABI because it impedes cerebral blood flow and is associated with ischemia and hypoxia. During the transfer, patient management should be focused on minimizing rises in the ICP level. Therefore, administration of hyperosmolar (mannital and hypertonic saline) for patients with severe brain injury before and during the transfer to reduce/control ICP should be considered (AANN, 2011).
During the transportation, external ventricular drains (EVDs) must be closed to prevent cerebral spine fluid over drainage and reopened at the ordered level when patient is once again settled (AANN, 2011). If the patent is unstable, EVD should be secured and checked on a regular basis (e.g., every 5–15 minutes to check the ICP). In addition, to reduce ICP, the patients’ head should be maintained midline to prevent impairment of blood flow in the external jugular veins, and head of bed should be elevated to 30°. When patients are transferred back to the unit, the EVD should be rechecked for patency and releveled with the tragus of the ear.
Evidence suggests that transports performed by trained personnel reduce adverse events and improve patient outcome (Beckmann, Gillies, Berenholtz, Wu, & Pronovost, 2004; Fanara, Manzon, Barbot, Desmettre, & Capellier, 2010; Papson et al., 2007). Nurses and respiratory therapists frequently accompany patients during intrahospital transport. Transfer of patients with ABI who require an EVD should be closely monitored by competent nurses (e.g., those with the certification and strong experience in critical care) to assess and manage neurological patients, especially those with drains. A patient with severe ABI with unstable physiology and those at risk of acute deterioration should be accompanied by a physician during transport (AAGBI, 2006).
A checklist as the one presented in Table 1 should be prepared, implemented, and documented to ensure a high-quality transfer of patients with ABI and better outcomes. The checklist should be practical and evidence based. The transfer checklist for ABI, as given in Table 1, summaries the main points that need to be verified including preparation, pretransport assessment (airway, breathing, circulation, and disability), standard of monitoring during transport, and documentation (AAGBI, 2006; Day, 2010; Fanara et al., 2010; Ferdinande, 1999; Jarden & Quirke, 2010; Warren, Fromm, Orr, Rotello, & Horst, 2004).
Recordings of vital signs, ICP, ICP waveforms, GCS, and neurological status should be made at regular intervals during and after the transport. Any events and interventions that occurred during the transport should be documented as well. In some cases, the hazards of transporting patients with severe brain injury could be avoided by using bedside tests or procedures in the ICU. For example, diagnostic modalities such as computed tomography, echocardiography, and ultrasound can be done at the bedside (Peris et al., 2010). Procedures such as tracheostomy, endoscopic gastrostomy, and placement of an inferior vena filter can also be performed in the ICU.
Because computed tomography imaging is universally performed for patients with ABI, the decision to repeat a scan must weigh the knowledge to be against the risk of additional SBI as well as the long-term effects of radiation exposure (Brenner & Hall, 2007). Portable computed tomography is feasible, easy to use, and safe. Portable scans provide adequate radiological quality for diagnostic purposes. Their use should lead to decreased transport-related mobility while helping to improve rapid decision making in the ICU, operation, and other location (Carlson & Yonas, 2012).
Transfer of patients with ABI is potentially hazardous if poorly executed. Patients with ABI are physically and neurologically unstable. Deterioration can occur during transport including hemodynamic instability, increased ICP, and oxygen desaturation. The SBI may occur during transport or worsen in patients with ABI. Preparation and management are crucial steps for safe patient transport. Patients with ABI should be stable before leaving the ICU. The technical aspects of transporting a patient as well as the human factors such as careful decision making require consideration and organization to avoid adverse events associated with transport. A checklist as the one presented in Table 1 should be prepared, implemented, and documented to ensure a high-quality transfer of patients with ABI and better outcomes.
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