Dr Ray Towey FRCA,
Consultant Anaesthetist,
Bugando Medical Centre, Mwanza, Tanzania.
mailto:emach@africaonline.co.tz

Introduction		Theatre
The Case		Operation
Initial Management		Post Operative Care
Comment		An Inexpensive ICP Monitor
Anaesthetic Management		Conclusion
IV Fluid Therapy

Introduction

This is a report of a patient who has suffered a head injury. The purpose is to illustrate the practical application of the basic physiological and pharmacological principles explained before ( Neurophysiology - Intracranial Pressure and Cerebral Blood Flow, Update in Anaesthesia 1998;8:4 and  Neuropharmacology - Intracranial Pressure and Cerebral Blood Flow, Update in Anaesthesia 1998;9:7). The problem is presented with the management and a range of anaesthetic techniques. 

The Case

Cycling to work in the morning, a fit 30 year old man has an accident which causes severe damage to his head. Initially he is conscious but confused, and is taken to the local Accident Department. When he is admitted it is found that he has become unconscious. 

Initial Management

An initial assessment is performed urgently, in the sequence described below.

• A Airway control including cervical spine immobilisation with a stiff collar.
• B Breathing
• C Circulation
• D Dysfunction or Disability
• E External Examination

His airway is clear. He is breathing adequately. His blood pressure is 180/90mmHg and he has a regular pulse with a rate of 55 bpm. There was no report of blood loss at the scene. He is warm and well perfused. Thus his circulation is adequate.

Neurological dysfunction is assessed by looking at conscious level, pupils and posture. Conscious state is assessed using the Glasgow Coma Score (GCS score Table 1) or the AVPU system. Glasgow Coma score range is 3-15, if it is less than 8, the patient has serious damage with raised intracranial pressure (ICP) more than 20 mmHg (normal 5-13 mmHg).

The AVPU is simple to carry out and offers a rapid method of assessment.

Patients who are not alert and are not responding to command (P or worse) are equivalent to a GCS of around 8 which indicates a severe injury.

On examination of the pupils the right pupil is found to be fixed and dilated, the left pupil is small and reacting. He is unresponsive to pain (GCS less 8, AVPU less than P). This is a neurological emergency where delay may result in a fatal outcome or major disability. A rapid secondary survey is carried out to exclude other life threatening injuries. Although the risk of neck injury is low, it cannot be excluded and therefore the neck is kept stabilised with a semi-rigid collar and sand bags or blocks joined with tape with straps across the forehead (figure 1). An IV infusion is started with normal saline (0.9%).

Cervical spine immobilisation with a long spine board, rigid collar, lateral blocks and straps.

Comment

As soon as the patient is admitted to hospital the basic ABCDE sequence described above is rapidly carried out to detect any problems such as airway obstruction or respiratory arrest which will rapidly cause death unless treated. With head injuries, respiratory obstruction will cause hypoxia and raised carbon dioxide and will lead to increased intracranial pressure causing severe secondary damage. An adequate blood pressure is vital in a patient with raised intracranial pressure.

The patient has suffered a primary head injury from trauma. The signs indicate a rapidly rising intracranial pressure, with coning of the temporal lobe probably due, in this case to an extradural haematoma. This is a rapidly fatal condition if it is not treated urgently. When treated quickly, a good recovery may result. It is essential that further brain damage from ischaemia (due to low blood pressure and cerebral swelling) resulting from factors such as hypoxia, high carbon dioxide levels and venous congestion does not occur. Hypotension and hypoxia will increase mortality of a patient with a severe head injury by 70-80%.  

Anaesthetic Management

Whenever possible the patient should be reviewed by an anaesthetist in the receiving room or accident department. As the patient has low AVPU and GCS scores, he needs to be intubated and ventilated to ensure a clear airway, full oxygenation and low normal carbon dioxide levels before going to the CT scanner. Since there is still concern regarding a possible neck injury, further movement of the neck during intubation could cause injury to the cervical cord. Therefore intubation is carried out with the head in the neutral position and manual in-line traction to prevent neck movement (figure 2). To perform this manoeuvre, an assistant grasps the mastoid processes and the front part of the collar is removed to allow adequate mouth opening. Do not apply excessive traction as this can cause further damage to the cervical spine.

Rapid sequence induction of anaesthesia and manual in-line cervical traction in an acute trauma patient.

The mouth is clear, but as he may have eaten breakfast recently, a rapid sequence induction is necessary. He is pre-oxygenated and given an intravenous narcotic fentanyl 150 mcg, (pethidine 50 mg or morphine 5 mg would be reasonable alternatives) followed by a slightly reduced dose of thiopentone 150-200 mg to ensure anaesthesia, without causing hypotension. Many places today are now using a reduced dose of propofol 90 - 100 mg, for induction and continuing anaesthesia with a propofol infusion. Cricoid pressure is applied, he is paralysed with 100mg of suxamethonium, and intubated once fasciculation has stopped.

It is important to maintain intermittent positive pressure ventilation for neurosurgical patients to produce a moderately low normal arterial CO2 (PaCO2 35 mmHg - 4.7 kPa) which will help to reduce cerebral swelling and hence intracranial pressure.

After tying in the endotracheal tube the blood pressure is measured again. It has fallen to 80/55 mmHg. 500mls of normal saline (0.9%) is rapidly given, and a 6mg dose of ephedrine is administered IV which restores the blood pressure to 180/90 mmHg. 

(Continued ...)

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