Critical Care Emergencies 11CARDIOPULMONARY RESUSCITATION(d) sometimes aspirating as little as 50 mL restores the cardiac
output, although immediate resuscitative thoracotomy is
usually indicated in cases resulting from trauma (see p. 237).
(vii) Toxins/poisons/drugs
(a) many substances cause cardiorespiratory arrest following
accidental or deliberate ingestion, such as poisoning with
tricyclic antidepressants (see p. 174), calcium-channel
blocking drugs (see p. 183) or -blockers (see p. 182), and
hydrofluoric acid burns (see p. 190)
(b) consider these based on the history, recognize early, and treat
supportively or with antidotes where available.
(viii) Thromboembolism with mechanical circulatory obstruction
(a) perform external cardiac massage, which may break up a
massive pulmonary embolus (PE), and give a fluid load of
20 mL/kg
(b) give thrombolysis such as alteplase (recombinant tissue
plasminogen activator [rt-PA]) 100 mg i.v. if clinical
suspicion is high and there are no absolute contraindications
(c) consider performing CPR for at least another 60–90 min
before termination of the resuscitation.8 The prognosis is usually hopeless if a patient is still in asystole. However,
consider pacing if P waves or any other electrical activity, such as a severe
bradycardia, are present with poor perfusion:
(i) Use an external (transcutaneous) pacemaker to maintain the
cardiac output until a transvenous wire is inserted.
(ii) A temporary transvenous pacemaker wire should ideally be
passed under X-ray guidance, but may be inserted blind via a
central vein.
9 Post-resuscitation care
It is important to continue effective CPR until the heartbeat is strong enough
to produce a peripheral pulse, and/or there are signs of life.
(i) Titrate oxygen delivery to maintain oxygen saturation 94–98%.
Avoid hyperoxaemia.
(ii) Check the ABG to exclude hypocarbia from over-ventilation,
which causes cerebral vasoconstriction with decreased cerebral
blood flow
(a) adjust ventilation to aim for normocarbia with a PaCO 2 from
35 to 45 mmHg (4.5 to 6 kPa).
(iii) Insert a gastric tube to decompress the stomach.
(iv) Contact the cardiology service urgently after cardiac arrest in
a suspected acute coronary syndrome, such as a cardiac arrest
following chest pain
(a) immediate percutaneous coronary intervention (PCI) may be
possible