Medicine Digests
Synopsis of Important Principles
- Critical illnesses are often associated with circulatory, respiratory, hepatic and/or renal dysfunction that may alter the pharmacokinetics and/or pharmacodynamics of drugs.
- Decisions about routes of administration and doses of drugs used during medical emergencies must consider the physiological status of the patient, the pharmacokinetic and pharmacodynamic characteristics of the particular drug, and how the two interact.
- Adverse drug reactions and interactions are more likely in critically ill patients due to the effect of the disease on drug kinetics, the decreased toxic-therapeutic ratio due to severe underlying illness, and the large number of medications that such patients receive. Adverse reactions to drugs should be considered when unexplained deterioration or failure to respond to therapy are encountered.
- Preservation of function of vital organs is a fundamental concept of critical care therapeutics. Preservation of cardiovascular functions requires attention to fluid and electrolyte status, prompt correction of arrhythmias and shock, and measures to preserve the myocardium against ischaemic injury.
- Preservation of respiratory function requires protection of the airway, cautious use of fluids and oxygen, and prompt recognition and management of infection.
- Preservation of cerebral function requires maintaining cerebral blood flow with adequate oxygen and glucose sufficient to meet the metabolic demands of the brain. This entails maintaining adequate systemic circulation, control of intracranial hypertension, and prompt control of seizures and hyperthermia.
- Critically ill patients are particularly susceptible to infections, gastric stress erosions and ulcers, adult respiratory distress syndrome, pulmonary emboli, and haemostatic disorders. The risks of such complications may be reduced by meticulous care of catheters, pulmonary toilet, cautious use of fluids, prompt treatment of infection when it occurs, and selective prophylactic drug therapies.
- Shock can be produced by many different processes including myocardial infarction, hypovolaemia, sepsis, drug overdose, burns, hypothermia, spinal cord transsection and anaphylaxis. Optimum treatment of shock depends on knowledge of the pathophysiology of the shock state and the pharmacology of the drugs.
- Features of acute drug intoxication include coma, agitated delirium, seizures, hypo- and hyperthermia, shock, arrhythmias, aspiration and pulmonary oedema. Successful therapy of acute drug intoxication depends on the integration and application of knowledge of the pharmacology of both the intoxicating drug and the drugs used in therapy, as well as the principles of supportive critical care.
Blood, Critical Care, Critical Illness, Disease, Dosage, Drug, Effect, Glucose, Hypertension, Infection, Medical Emergencies, Medication, Respiratory, Syndrome, Therapeutic, Therapy, Toxic, Treatment
