Staff

The work makes special demands on nursing and medical personnel. The nurse has greater responsibility than in an ordinary ward, and will often have to act quickly and initiate a prearranged programme of treatment. The staff must be fully trained and continuously available. The pace of events and the inevitable failures in treatment have an effect on morale. It is important that an atmosphere of calm and cheerfulness is created. The medical management also presents problems, and it must be clear to everyone concerned which consultant is responsible for the management of each patient. The skills of the anaesthetist are often required. The unit can conveniently be administered by a specialist in intensive care, an anaesthetist, or a chest physician. Regular consultation with other experts is essential.

Environment

The environment of the intensive care unit is highly significant, because most patients will have difficulty in concentrating on any activity other than their own treatment for longer than a few minutes. The room should provide adequate space, be well lit, and, if possible, have views that preserve contact with normal activities. In should be quiet and situated away from noisy corridors. Buzzers and flashing lights should be reduced to a minimum.

Observation and monitoring

Charting of the pulse rate, blood pressure, respiratory rate, core and skin temperature and fluid balance is usually a routine. The frequency of observations will vary with the case, and computer systems are useful for on-line recording.

Skin temperature is conveniently recorded using a thermocouple, and core temperature with a probe in the external auditory meatus or lower oesophagus. Rectal temperature measurements carry some risk of spread of infection. A continuous display of the cardiograph on an oscilloscope is useful. Central venous pressure can be monitored with a catheter in the right atrium. Chest radiographs must be easily obtained, usually with portable equipment. The blood pressure can be recorded continuously if an intra-arterial catheter is used.

These are basic requirements, but computers provide more elaborate records and automatic alarm signals. Closed-circuit television is no substitute for the presence of staff adjacent to the bed.

While these facilities can be expected in a unit, many aspects of intensive care impinge on daily management of patients who do not require all the facilities of the special unit. Some of these will now be considered in a general way to avoid repetitive discussion later in the book. No attempt is made to cover all aspects of the subject, and only points of special significance for the neurological patient will be discussed.

Monitoring of intracranial pressure

The harmful effects of raised intracranial pressure have long been recognized but continuous monitoring is a recent development. Lumbar puncture is potentially dangerous in these patients. The pressure may be measured by using a catheter inserted through a burr hole into the frontal horn of the lateral ventricle. The manometer system is attached to a transducer with a chart for continuous recording. Observations of this type show that very marked and sometimes rapid changes in pressure may occur in patients with intracranial tumour or haemorrhage (Figure 1.1 and Figure 1.2).

The normal intracranial pressure with the patient lying flat is usually 0–10 mmHg or 0–13.6 cm H2O (7.5 mmHg = 1 kPa) and may increase tenfold during coughing or straining. The wave pattern is altered by arterial pulsation and respiration.

A rise in pressure to 40 mmHg may be regarded as moderate but it may reach much higher levels. Plateau waves rising abruptly to 50 mmHg and persisting for 30–60 minutes strongly suggest an intracranial mass lesion. A rise in pressure may be due to obstruction of cerebrospinal fluid (CSF) flow but brain oedema, stiffness of brain tissue, tentorial herniation, CO2 retention, hypoxia, restless sleep, pyrexia and general anaesthesia are important contributory factors. High CSF pressure interferes with blood flow and if it equals the arterial pressure brain perfusion ceases.

Treatment directed towards control of the pressure is likely to be needed if the level reaches 30 mmHg and action may be required at lower levels when other clinical signs show progression.

Pressure monitoring is most often required in severe head injury, cerebral haemorrhage, hydrocephalus and brain tumour.

Rising intracranial pressure not caused by airway obstruction, jugular compression, hypoxia, or postural change may be due to an expanding lesion which requires urgent surgical relief. As a temporary measure intravenous mannitol infusion of 200 ml of 20% solution may be used. This may be combined with intermittent positive pressure respiration and closed drainage of the ventricular fluid.

Recognition of change

The general observation and monitoring of the patient are designed to ensure early recognition of any deterioration.

In assessing conscious level, it is best to record the type of response, rather than rely on numerical or other grading which may vary in significance according to different observers. It is useful to record the patient’s conscious level in such terms as: alert, responding readily to command, responding to command but tending to lapse into a drowsy state when not stimulated (stupor), responsive to pinch or pinprick, response to supraorbital pressure, or unresponsive.

The Glasgow Coma Scale has been used mainly in the management of head injuries and was designed to monitor progress and provide a numerical index of prognosis. It is based on the ability of the patient to obey commands, speak, and open the eyes when these functions are not disturbed by local causes such as superficial haematoma or tracheostomy. The aggregate score (Figure 1.3) is in the range 3–15.

The motor response to command must be distinguished from a grasp reflex or spinal reflex response. The best response is recorded. A pencil applied to the nail or skin is a suitable stimulus to induce pain. A localizing response to pain is based on retraction of a limb when stimulated at more than one site. An extensor response to pain is abnormal and found in decerebrate states.

The verbal responses are useful where the speech mechanism is intact and expression in words allows classification into ‘orientated’, ‘confused’, and...