Neurocritical Care

28. Decisions in Persistent Vegetative State

A 17-year-old teenager remained comatose 2 weeks after a severe traumatic brain injury. During the first days following the accident, he was treated for refractory increased intracranial pressure associated with multiple frontal and temporal lobe contusions. A frontal decompressive craniectomy was needed at some point. His clinical course was complicated by seizures, pulmonary infection, and bacteriemia. Early decubital redness appeared. After resolution of the intracranial hypertension no change in his neurologic examination was noted, and he has stayed comatose. He has not developed sleep and wake cycles. On examination, he has his eyes open at times, but is not tracking a finger, nor fixating on his parents when they are in the room. A loud handclap does not produce any reaction. He grinds his teeth. There is spontaneous extensor posturing. He may sweat profusely occasionally.

All clinical indicators point toward the development of a persistent vegetative state. The nursing staff has not noticed any signs of awareness, but the family is not so sure. Long-term support is desired. There are questions by the family members whether improvement can occur and at what level the patient might be able to function.

What do you do now?

Outcome prediction in young patients after severe traumatic brain injury is a necessary task for neurosurgeons and neurologists. When patients display clinical signs of a persistent vegetative state and also have neuroimaging documentation of severe brain injury, the need for long-term care will come up and decisions will have to be made.

There are multiple prediction models in head injury. The largest database of traumatic head injury (IMPACT; International Mission for Prognosis and Analysis of Clinical trials in Traumatic brain injury) uses admission characteristics to calculate a prognosis estimate. These are age, motor response, pupil responses, presence of hypoxia and hypotension, CT categorization into severity of lesions and presence of a mass lesion, presence of traumatic subarachnoid hemorrhage, epidural mass, and also serum glucose and hemoglobin values (calculator at www.tbi-impact.org). In our patient example, the predicted 6 months mortality is 64% and predicted 6 months unfavorable outcome (death, vegetative state, and severe disability) is 83%. Hopeful parents will be encouraged by these numbers. Physicians will express serious doubt. Every physician involved with long-term care of traumatic brain injury will know that we can never be certain and prediction in young comatose patients with intact brainstem reflexes has serious limitations.

The general guide is that if the clinical findings of persistent vegetative state are still present after 3 months in nontraumatic coma (i.e., anoxic-ischemic encephalopathy, hypoglycemia, CNS infections, status epilepticus) substantial recovery of awareness is not anticipated. In traumatic brain injury, 12 months are needed for reasonable certainty, but recovery to a minimally conscious state may occur beyond this time limit.

There has been renewed interest in persistent vegetative state and the accuracy of the clinical diagnosis. The diagnosis of persistent vegetative state is well defined (Table 28.1). The common questions have been: Is persistent vegetative state truly persistent? Is our neurologic examination reliable? Do we have better ways to assess “consciousness?” Can functional MRI scans predict recovery? Can functional MRI scans find evidence of some awareness not detected clinically? The reliability of neurological examination has withstood the test of time, although errors by non-neurologists are still considerable. Some of the above questions cannot be answered yet with certainty. Functional MRI scan remains a research tool, but brain activation on a functional MRI does not mean consciousness.

TABLE 28.1 Clinical Signs of Persistent Vegetative State

Breathing regular (with tracheostomy in place)

Bronchial hypersecretion

Blood pressure stable

Immobile

Flexion-extension contractures

Eyes closed or open

No evidence of focus or holding attention

No eye movements to examiner (except briefly when suddenly confronting)

Eyes roving, nystagmoid, gaze preference changing, no eye contact for more than 5 seconds

Eyes may move upward or downward or assume lateral gaze for 1–2 minutes

No sound (if not made impossible with tracheostomy)

Spontaneous teeth grinding

Spontaneous clonus, or shivering

Once long-term care has been decided, a tracheostomy and percutaneous endoscopic gastrostomy (PEG) should be placed, often simultaneously (Table 28.2). Common contraindications for a PEG are: active coagulopathy, inability to perform endoscopy (pharyngeal obstruction), prior abdominal surgery involving the stomach, and most importantly, uncertainty about need for long-term care (it is poor medical practice to place a tracheostomy and PEG if care is withdrawn weeks later).

Usually a general surgeon will perform these procedures. Enteral feeding is discontinued 12 hours before surgery. Antibiotic prophylaxis to reduce peristomal infection is administered, and feeding can be started 24 hours or less after placement. Complications are quite infrequent and some can be anticipated. Pneumoperitoneum is common due to air escaping through the stomach opening and is only concerning when peritonitis occurs. Air can be obscured by concomitant pulmonary infiltrates, and upright X-ray of the chest is needed to make the diagnosis in these cases.

TABLE 28.2 Precautionary Measures with Gastrostomy and Tracheostomy

Checks with gastrostomy placement

INR < 1.5; platelets > 50,000/mm3

Discontinue intravenous heparin or antiplatelet agents (5 days)

Cefotaxime 2 gram IV single dose

Fasting for 4-6 hours

Anticipate use of midazolam (may need airway protection)

Resume tube feeding 1 hour after placement

Monitor for pneumoperitoneum with upright chest X-ray

Monitor white blood cell counts with fever

 

Checks with tracheostomy placement

BMI < 30 kg/m2

Stable cervical spine fracture

No high PEEP (< 10 cm H2O) or high FiO2 requirements

INR < 1.5; platelets > 50,000/mm3

Discontinue intravenous heparin

Anticipate oxygen desaturation

Anticipate hypotension

Anticipate bleeding at site

BMI: Body Mass index; PEEP: positive end expiratory pressure; FiO2: fraction of inspired oxygen; INR: international normalized ratio.

The advantages of tracheostomy in permanently comatose patients are substantial. These include ease of suctioning, reduced requirement of sedation, shorter duration of mechanical ventilation and ability to transfer patients to a long-term facility. Timing of tracheostomy placement has been a topic of debate. Early performance of tracheostomy (sometimes as early as within the first week of mechanical ventilation) has been proposed in patients expected to require prolonged mechanical ventilation; however, the value of this practice has not been proven. We favor the more conservative approach of proceeding with a percutaneous tracheostomy at least 10 days after the start of mechanical ventilation and when need for more than 3 weeks of mechanical ventilation is anticipated. Direct tracheostomy (i.e., without previous endotracheal intubation) may be needed in severe neck and facial trauma or when there is inability to secure an airway. Complications of percutaneous tracheostomy are very uncommon when done by skilled surgeons (less than 2%), but percutaneous tracheostomy cannot be considered in patients with possible cervical neck injury, morbid obesity, and significant coagulopathy. Continuous need for intravenous heparin may make management of the bleeding site also difficult. Eventually patients will have the tracheostomy down-sized. Uncomplicated plugging of the tube for several days (“corking”) indicates that decannulation can be considered.

Long-term care in a nursing home facility is needed, and patients are typically followed by physicians who face a continuous challenge to prevent and treat infections. Superb nursing care and physical therapy are essential to prevent early and late fatal complications.

KEY POINTS TO REMEMBER REGARDING DECISIONS IN PERSISTENT VEGETATIVE STATE

· Prognostication after traumatic head injury can be assisted by the use of large database models (such as IMPACT), but these models are far from perfect.

· Persistent vegetative state is considered permanent one year after traumatic brain injury, but already permanent 3 months after nontraumatic coma. There are exceptions.

· Tracheostomy and PEG are essentially part of the decision to maintain best long-term support of the patient and should be considered early.

Further Reading

Bernat JL. Chronic disorders of consciousness. Lancet 2006; 367:1181–1192.

Durbin CG. Tracheostomy: why, when, and how? Respir Care 2010; 55:1056–1068.

Lingsma HF, Roozenbeek B, Steyerberg EW, Murray GD, Maas AI. Early prognosis in traumatic brain injury: from prophecies to predictions. Lancet Neurol 2010; 9:543–554.

Kornblith LZ, Burlew CC, Moore EE et al One thousand bedside percutaneous tracheostomies in the surgical intensive care unit: Time to change the gold standard. J Am Coll Surg 2011;21:163–170.

Koc D, Gercek A, Gencosmanoglu R et al. Percutaneous endoscopic gastrostomy in the neurosurgical intensive care unit: complications and outcome. JPEN J Parenter Enteral Nutr 2007;31:517–520.

Loser C, Aschl G, Hebuterne X, Mathus-Vliegen EMH, Muscaritoli M, Niv Y, Rollins H, Singer P, Skelly RH. ESPEN guidelines on artificial enteral nutrition–percutaneous endoscopic gastrostomy (PEG). Clinical Nutrition 2005; 24:848–861.

Wijdicks EFM. The Comatose Patient. Oxford University Press, New York, 2008.