Aspiration of gastric contents

RISQUES et COMPLICATIONS en ANESTHESIE

I. Selon la période d’anesthésie

: Induction-intubation, période per opératoire et postopératoire.

II. Selon le type de Chirurgie

: Majeur, Modéré, Mineur.

III. Selon le type d’anesthésie

: Anesthésie générale, loco-générale.

IV. Selon les atteintes Systémiques

: Cardiovasculaire, Respiratoire, digestif, neurologique, hépatique, Rénale, pancréatique, système sanguin, hydroélectrique, acido-basique.

V. Classification ASA

I. Selon la période d’anesthésie

1) Induction –intubation

a) Obstruction des voies aériennes

Acute Airway obstruction

This may present in a variety of ways:

Conscious patient

• Usually distressed and unwilling to lie down. • Marked respiratory effort, using accessory muscles (e.g. sternomastoids). •Indrawing of intercostal and supraclavicular regions and a tracheal tug. • Stridor. If inspiratory, consider obstruction above the larynx. •Tachycardia and hypertension secondary to hypoxia and hypercarbia. • The history, if available, may indicate the cause; for example inhaled foreign body, oedema (allergic reaction, inhalational injury), infection (epiglottitis), tumour or trauma.

Unconscious patient

• Usually secondary to unrelieved obstruction causing hypoxaemia and hypercarbia. • Minimal respiratory effort. • Paradoxical movement of the chest and abdomen (see-saw ventilation). • Minimal or no breath sounds (silent chest). • Hypotension, a variety of arrhythmias, cyanosed.

Management

Whatever the circumstances, the aim is to secure a patent airway to allow adequate oxygenation. • Increase the inspired oxygen concentration to 100%. • Get help urgently. • If not already available, request the emergency airway equipment.

In the conscious patient• If safe to do so, transfer rapidly to the anaesthetic room in theatre. • If ventilation is reasonable, induce anaesthesia using an inhalational anaesthetic in oxygen. Increasing the inspired concentration too rapidly may cause coughing and worsen the obstruction. • Gentle manual supplementation of ventilation may be possible. •When anaesthesia is adequate perform direct laryngoscopy. • Intubate if possible. • If this fails, and the airway is adequate, carry out formal tracheostomy. • If this fails, and the airway is inadequate, carry out needle cricothyroidotomy. Under some circumstances it may be safer initially to carry out needle cricothyroidotomy under local anaesthesia to allow oxygenation before inducing anaesthesia and direct laryngoscopy.

In the unconscious patient

• Attempt ventilation with 100% oxygen. • Perform direct laryngoscopy quickly, once only. If possible: •Remove any foreign bodies under direct vision using Magill’s forceps. • Pass a small-diameter (5.0 mm) tracheal tube past the obstruction into the larynx. • If this fails, proceed rapidly to either needle or surgical cricothyroidotomy. • Once oxygenation is restored, the patient may recover consciousness rapidly. Sedation and neuromuscular blocking drugs may be required while the airway is formally assessed.

In the anaesthetized patient

• Attempt to ventilate with 100% oxygen. • Perform direct laryngoscopy. • If possible pass a small-diameter (5.0 mm) tracheal tube past the obstruction into the larynx. • If unsuccessful, proceed to cricothyroidotomy.

: Estomac plein->NV

Aspiration of gastric contents

The greatest risk is during induction of anaesthesia, but some patients are also at risk during extubation and recovery. Postoperative patients on the ward who have received liberal amounts of opiates for pain relief or have impaired pharyngeal reflexes may also aspirate. The incidence of complications appears to be related to both the volume (>25mL) and pH (<2.5) of the material aspirated.

Factors predisposing to aspiration include: •delayed gastric emptying; • obstetric patients; • drugs, especially opiates; • trauma patients, particularly head injury; • intestinal obstruction or peritoneal irritation; • blood in the stomach;

sympathetic stimulation, pain and anxiety; •a full stomach:

• an inadequate period of starvation; • distension with mask ventilation;

•a history of gastro-oesophageal reflux or a hiatus hernia;obesity; •head-down position;presence of a bulbar palsy; •oesophageal pouch or stricture. Signs suggesting aspiration include:coughing during induction or recovery from anaesthesia;the presence of gastric contents in the pharynx at laryngoscopy or around the edge of the facemask;progressive hypoxia;bronchospasm;respiratory obstruction, if severe;occasionally, aspiration may go completely unnoticed during anaesthesia, with the development of hypoxia, hypotension and respiratory failure postoperatively.

Date: 2016-01-05; view: 729