Pharmacological management of the aroused patient

Essentials

1
Benzodiazepines and antipsychotics, often used most effectively in combination, are the first-line drugs for sedation of the aroused patient.
2
As much information as possible should be collected before the patient is sedated.
3
The risks involved in administering sedative drugs need to be considered, particularly at higher doses.
4
Dose adjustments are necessary in the older or medically compromised patient.

Acknowledgements

The chapter authors of this edition would like to acknowledge the important contribution of the author of previous editions, including Dr. Simon Byrne.

Introduction

Aroused patients who present to the emergency department (ED) of their own accord can generally be best assisted by verbal reassurance and prompt mental health evaluation. Reducing the waiting time and arriving quickly at an action plan will provide the best response to the patient’s anxiety and agitation.

For highly aroused patients who have been brought to the hospital reluctantly, the immediate need is to gain control of the situation to permit further evaluation, while ensuring the safety of the patient, the staff and the public.

Where possible, it is desirable to collect some information about the patient before sedation. The patient should be approached in a calm manner in a safe, observed area of the ED, with security staff in the background if necessary. The patient should be asked about his or her understanding of the problems and listened to attentively, even if the account is incoherent. This attention will be reassuring to the patient and helps in building rapport. During this process observations can be made about the mental state. If possible, vital signs should be recorded and a brief physical examination carried out, with particular attention to signs of injury, intoxication or overdose.

In the hostile or frightened uncooperative patient, it will often be necessary to proceed to rapid tranquilization. This is a familiar procedure to the emergency physician and the practice can be enhanced by attention to the basic principles of care, an awareness of the risks and knowledge of the characteristics of the available drugs.

Pharmacological management should always be tailored to the particular patient. The medically compromised patient will be at greater risk of the complications of sedation. In elderly patients, decreased and delayed metabolism and elimination can result in prolonged therapeutic and adverse effects. Dose adjustments and agents with shorter half-lives and more favourable side-effect profiles must be considered for these patients.

General principles of rapid tranquillization

The general principles of care are:

Use sedative benzodiazepines and/or antipsychotics as the first-line agents.
Should the situation allow, oral dosing is the least distressing approach for patients and staff.
Treating physicians should use agents with which they are familiar. In particular, they should be aware of maximal safe dosing and expected adverse effects.
The endpoint should be a calm cooperative patient. Sedation to the point of loss of airway protection is dangerous.
The patient should be nursed in a quiet, calm and gently lit environment if possible.
Sedated patients should be monitored with basic observations; a 12-lead electrocardiogram (ECG) should be performed on any patient being administered repeat doses of antipsychotics.
Supportive care, such as hydration, indwelling catheterization, pressure care and deep vein thrombosis prophylaxis, are essential for patients requiring ongoing sedation. This is particularly relevant in overcrowded EDs and if patients are detained in the ED for prolonged periods.
Maintenance of patient dignity by using single rooms and limiting visual exposure of the patient to the public is often forgotten but should be a basic standard of care.

Risks of rapid tranquillization

There are inherent risks in attempting to gain control of the aroused patient, including risks of injury to the staff and patient. If physical restraint is necessary to administer parenteral medication, adequate staff, trained in restraint procedures should be on hand. Sometimes mechanical (padded strap) restraint may be necessary in the early stages or to limit the dose of medication if the patient is developing toxic effects. Mechanical restraint should not be maintained in the absence of chemical sedation due to the risks of physical injury and rhabdomyolysis, as well as for ethical reasons.

The risks of adverse events from medication administration are well recognized.

Over-sedation and resultant respiratory depression and pulmonary aspiration are relatively common and for the most part avoidable with proper care.

Sudden cardiac death, particularly with agents that prolong the QT interval and precipitate torsade des pointes and ventricular tachycardia (VT), is a rare but catastrophic complication of rapid tranquilization. This risk is heightened in the aroused patient with increased circulating catecholamines and in patients with pre-existing heart disease or conduction disturbance. Antipsychotics combined with other medications that prolong the QT interval pose an increased risk. The agents most associated with risk of sudden death are thioridazine and clozapine. Droperidol and haloperidol are associated with QT prolongation but rarely with the risk of torsade des pointes. Quetiapine and chlorpromazine are associated with QT prolongation but this is probably less clinically significant than with the above agents. The atypical agent olanzapine appears to be relatively safe from this perspective.

Hypotension can occur with administration of any agent with alpha blockade effects, but is especially associated with chlorpromazine (particularly when given intravenously). Dystonic reactions are seen with all antipsychotics, most frequently with the butyrophenones, such as haloperidol, and less commonly with atypical agents, such as olanzapine. Neuroleptic malignant syndrome is a risk with any antipsychotic agent, even following a single dose.

Anticholinergic effects, such as delirium and urinary retention, are risks with virtually all antipsychotics and are generally seen at high doses. Delirium is also caused by high doses of benzodiazepines, particularly diazepam, which accumulates with recurrent dosing. All antipsychotics have the potential to lower the seizure threshold.

Elderly patients are at significantly greater risk of drug accumulation and adverse effects. They are also at far greater risk of delirium, particularly with the combination of possible underlying cognitive impairment and environment change. Age-related reductions in hepatic metabolism and renal function make it reasonable to assume that all agents will have prolonged elimination half-lives in these patients. Even small doses of benzodiazepines can produce significant and prolonged respiratory depression in the elderly. Standard doses of antipsychotics, such as haloperidol, may result in prolonged extrapyramidal effects that impair mobility for days to weeks post-administration.

Specific agents

Benzodiazepines

Midazolam

This water-soluble benzodiazepine has major benefits over diazepam in that it produces fewer site reactions and can be given intramuscularly. It has a rapid effect by intramuscular (IM) or IV injection (2 to 5 minutes), with a half-life of 1 to 3 hours. The active metabolite has a similar half-life. The elimination half-life is significantly prolonged in the elderly. The major adverse effect is respiratory depression. It is available in ampoules (5 mg/mL, 15 mg/3 mL, 5 mg/5 mL and 50 mg/10 mL).

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here