Acute severe asthma

This is characterized by any one of: • Severe breathlessness:

• an inability to complete a sentence in one breath; •a silent chest; • cyanosis.

•Tachypnoea: respiratory rate >25 breaths/min. •Tachycardia: heart rate >110 beats/min. • Peak expiratory flow (PEF) 33–50% of best or predicted.

Acute severe asthma is considered life threatening in a patient with any one of the following: • feeble respiratory effort; • PEF <33% of best or predicted; • SpO2<92%;

• PaO2<8kPa; • normal PaCO2

(4.6–6.0 kPa); • cyanosis; • bradycardia, arrhythmias, hypotension; • exhaustion, confusion, coma.

Immediate management

• High-flow oxygen. • High-dose beta-2 agonists via oxygen driven nebulizer. • Salbutamol 5mg, terbutaline 10 mg. • Ipratropium bromide, 0.5 mg via oxygen driven nebulizer. • Prednisolone 40–50mg orally, or hydrocortisone 100mg IV, or both.

Monitor

• PEF, 15–30 min intervals. • Pulse oximetry: maintain SpO

> 92%. • Arterial blood gases. •A chest X-ray is only indicated if:

• there is suspected pneumothorax or pneumomediastinum; • there is suspected consolidation; • there is failure to respond to therapy; • mechanical ventilation is required.

Subsequent management

If the patient is improving: • continue oxygen therapy; • give IV hydrocortisone 100 mg 6 hourly or 40– 50mg orally daily; • give nebulized salbutamol and ipratropium 4–6 hourly. If the patient is not improving: • continue oxygen therapy; • give nebulized salbutamol 5 mg more frequently, every 15–30mins or 10mg continuously hourly; • continue ipratropium 0.5 mg 4–6 hourly; • give magnesium sulphate 1.2–2.0g IV as slow infusion over 20 mins; • consider IV beta-2 agonist or aminophylline; • consider need for tracheal intubation and mechanical ventilation. Discuss with Critical Care team if there is: • need for tracheal intubation and ventilatory support; • continuing failure to respond to treatment; •a deteriorating PEF; • persistent or worsening hypoxia;

• hypercapnia; • development of acidosis (fall in pH or increase in hydrogen ion concentration); • exhaustion; • drowsiness or confusion; • coma; • respiratory arrest.

a) Hypoxémie

: Intubation sélective, œsophagienne, dimension du tube d’intubation non conforme, défaut du respirateur, du système d’approvisionnement en O2

b) Hémodynamique

: Hypotension (surdosage des AA, MP), choc anaphylactique (allergie à l’ATB, CR, AA, SR histamine- libérateurs)

Hypertension (AA, M insuffisantes)

Severe hypotension

Hypotension is a result of a reduction in either the cardiac output or the peripheral resistance, alone or in combination (blood pressure = cardiac output ¥ peripheral resistance). Severe hypotension may

be defined as a systolic pressure 40% less than the preoperative value.

Etiologies des l’hypotensions systemiques

Hypovolaemia• Dehydration/inadequate fluid intake • Haemorrhage • Severe vomiting/diarrhoea • Burns • Abnormal fluid losses into the gut • High output fistula of the small bowel

Cardiogenic causes• Acute myocardial ischaemia/infarction • Severe valvular heart disease • Cardiomyopathy • Acute myocarditis • Constrictive pericarditis

Sepsis• Any cause of systemic sepsis

Neurogenic• High spinal cord injury

Anaphylaxis

Date: 2016-01-05; view: 687