Breathing: any obvious injuries must be noted, the trachea should be checked for deviation and both sides of the chest for expansion. The thorax must be percussed, and lung apices and the axillae auscultated. If the patient has been intubated but the position of the tube is in doubt, then listening over the stomach may reveal an inadvertent oesophageal intubation. The respiratory rate must be noted. If available, a pulse oximeter is useful as it gives an indication of the adequacy of perfusion as well as arterial oxygen saturation. High concentration oxygen (6-8 litres/minute) should be administered to every patient. The following life threatening conditions need immediate treatment:

• Tension pneumothorax

• Massive haemothorax

• Flail chest

• Open chest wound

• Disruption of the tracheobronchial tree

A tension pneumothorax is suggested by a rapid respiratory rate, mediastinal (and tracheal) shift away from the affected side, and hyper-resonance and reduced breath sounds on the affected side. It should be treated initially by needle decompression of the pleural cavity at the second intercostal space in the mid clavicular line, followed by formal pleural drainage with an underwater seal. It is important to remember that a simple pneumothorax may be converted to a tension pneumothorax when a patient is ventilated and in this situation a chest drain should be inserted prophylactically prior to commencing ventilation.

A massive haemothorax is suggested by reduced breath sounds, dullness to percussion and a shift of the mediastinum away from the affected side often accompanied by cardiovascular instability. It should be treated with formal pleural drainage and if the initial volume of blood exceeds 1500mls or bleeding persists at a rate exceeding 200ml/hr thoracotomy is indicated. Before diagnosing either of these conditions in a ventilated patient, it is important to check that the endotracheal tube is in the trachea and that it has not entered the right main bronchus as this may mimic some of the above signs.

Flail chest means that part of the chest wall is able to move independently to the remainder and occurs when ribs are fractured in at least two places. It can be recognised when the flail segment falls during inspiration as the rest of the chest rises. It is always associated with significant pulmonary contusion resulting in hypoxia. If respiratory failure supervenes despite oxygen therapy and adequate analgesia (preferably epidural or intercostal blockade), then ventilation is required.

An open chest wound needs covering and sealing on three sides immediately ( figure 5). A one way valve is formed by the flapping motion of the free edge of the dressing and this prevents air being sucked into the pleural cavity from the outside.

This should be followed by formal pleural drainage and possible thoracotomy when the patient's condition has been stabilised. Once the pleural cavity is drained, the wound can be sutured or covered with an occlusive dressing.

Circulation and haemorrhage control: any major haemorrhage that is visible should be controlled by direct pressure. Tourniquets should not be used to prevent bleeding from a limb as they occlude collateral circulation causing tissue destruction. Penetrating wounds should be identified and explored formally by a surgeon. Penetrating implements should be left in situ for formal surgical exploration. A rapid assessment of the cardiovascular system should be made including pulse rate, skin colour, capillary refill (the time taken for colour to return to a finger pad after it has been briefly compressed >2 seconds is abnormal), level of consciousness and blood pressure.

An inadequate circulation is often called shock, and in multiply injured patients the most common cause is haemorrhage. It should be remembered that blood loss from a fractured humerus can be up to 800mls, from a femur up to 2000mls and from a fractured pelvis up to 3000mls. In the early stages, hypovolaemia can often be tolerated without change in the systolic blood pressure due to autonomic nervous system reflexes. To assess the status of the patient the signs of inadequate circulation and the sympathetic response to it must therefore be elicited. Hypovolaemia is often categorised into the 4 classes shown in Table 1 with their appropriate signs. It must be stressed that there is variation from this guide, particularly in the elderly, in those with previous medical conditions or those who are taking cardiovascular medications who all tolerate hypovolaemia poorly, and in fit young patients who often tolerate it well. It should also be remembered that anaesthesia will obtund the signs of sympathetic nervous system activation. The weight of the patient will need to be estimated to calculate fluid requirements.

Table 1:

Class of hypovolaemia	Class I	Class II	Class III	Class IV
Blood Loss: % Circulating volume	<15	15-30	30-40	>40
Blood Loss: Volume (mls in adults)	<750	750-1500	1500-2000	>2000
Pulse	Normal	100-120 bpm	120 bpm Weak	>120 bpm Very weak
Blood Pressure: Systolic	Normal	Normal	Low	Very Low
Blood Pressure: Diastolic	Normal	High	Low	Very Low
Capillary Refill	Normal	Slow	Slow	Absent
Mental State	Alert	Anxious	Confused	Lethargic
Respiratory Rate	Normal	Normal	Tachy- pnoeic	Tachy- pnoeic
Urine Output	>30 mls/hr	20-30 mls/hr	5-20 mls/hr	<5 mls/hr

(Continued...)

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