Why aspirate gastric contents

Subsequent clinical courses followed 3 patterns: 12 per cent of the patients died shortly after aspiration; 62 per cent had rapid clinical and radiologic improvement, with clearing, on average, within 4.

Treatment from the outset by adrenocortical steroids or antimicrobial agents had no demonstrable effect on the outcome. The clinical features of aspiration of gastric contents are characteristic and distinguish it from other forms of aspiration-related lung disease.

Altered physiological states such as pregnancy, labour, abdominal pain, gastrointestinal orders, renal failure and diabetes will alter the rate of gastric emptying, as well as drugs such as opioids. As suggested above, patients at greatest risk are those undergoing unplanned surgery, but also inadequate level of anaesthesia, those with abdominal pathology or the obese. Other examples are found below:. Table 1: Predisposing factors for aspiration under general anaesthesia. This usually occurs in two phases — firstly desquamation of the bronchial epithelium causing increased alveolar permeability.

This results in interstitial oedema, reduced compliance and VQ mismatch. The second stage, occurring within 2 to 3 hours, is due to an acute inflammatory response, mediated by proinflammatory cytokines such as tumour necrosis factor alpha and interleukin 8 and reactive oxygen products. Clinically, this may be asymptomatic, or present as tachypnoea, bronchospasm, wheeze, cyanosis and respiratory insufficiency.

This occurs either as a result of inhaling infected material or secondary bacterial infection following chemical pneumonitis. It is associated with typical symptoms of pneumonia such as tachycardia, tachypnoea, cough and fever, and may be evidenced by segmental or lobar consolidation classically right middle lobe on chest radiography. The disease process is similar to a community acquired pneumonia although the complication rate is higher, with cavitation and lung abscess occurring more commonly.

If particulate matter is aspirated, acute obstruction of small airways will lead to distal atelectasis. If large airways are obstructed, immediate arterial hypoxaemia may be rapidly fatal. Unnecessarily prolonged nil by mouth NBM orders lead to dehydration and possibly hypoglycaemia, with resultant thirst, hunger, discomfort and irritability. Current guidelines are 2 hours for clear fluids, 4 hours for breast milk, and 6 hours for a light meal, sweets, milk including formula and non clear fluids.

Histamine H 2 antagonists and proton pump inhibitors PPIs are commonly used to increase gastric pH, although they do not affect the pH of fluid already in the stomach. Oral sodium citrate solution reliably elevates gastric pH above 2.

H 2 antagonists act by blocking H 2 receptors of gastric parietal cells, thereby inhibiting the stimulatory effects of histamine on gastric acid secretion.

An oral H 2 antagonist must be given hours before anaesthesia, and a PPI, 12 hours in advance. A recent meta-analysis by Clark et al suggested that ranitidine was superior to PPIs in both reducing gastric fluid volume and acidity. Its use is recommended in patients at risk of aspiration only, not routinely. Metoclopramide has a prokinetic effect promoting gastric emptying, but there is little evidence to support its use.

Chest , 57 , Pulmonary fibrosis associated with tracheobronchial aspiration. A study of the frequency of hiatal hernia and gastroesophageal reflux in interstitial pulmonary fibrosis of obscure etiology. Chest , 69 , Aspiration resulting from gastroesophageal reflux. A cause of chronic bronchopulmonary disease. Chest , 93 , Surfactant alterations in acute inflammatory lung injury from aspiration of acid and gastric particulates.

Effects of gastric alkalinization on bacterial colonization in critically ill patients. Critical Care Medicine , — The role of intragastric acidity and stress ulcus prophylaxis on colonization and p. Pulmonary aspiration of gastric content. American Reviews in Respiratory Diseases , , High-dose corticosteroides in patients with the adult respiratory distress syndrome.

New England Journal of Medicine , , Early methylprednisolone treatment for septic syndrome and the adult respiratory distress syndrome. Chest , 94 , Physiological effects of corticosteroids in foodstuff aspiration.

Archives of Surgery , , Bartlett JC. Anaerobic bacterial infections of the lung and pleural space. Clinical Infectious Diseases , 16 Suppl.

Microbiology of severe aspiration pneumonia in institutionalized elderly. Reappraisal of clindamicyn IV monotherapy for treatment of mild-to-moderate aspiration pneumonia in elderly patients.

Chest , , Reflex airway reaction to fluid aspiration. Journal of Applied Physiology , 17 , Intermittent enteral feeding: the influence on respiratory and digestive tract colonization in mechanically ventilated intensive care unit patients. Continuous enteral feeding counteracts preventive measures for gastric colonization in intensive care unit patients.

Critical Care Medicine , 22 , All Rights Reserved. Under the terms of the licence agreement, an individual user may print out a PDF of a single chapter of a title in Oxford Medicine Online for personal use for details see Privacy Policy and Legal Notice. Oxford Medicine Online. Publications Pages Publications Pages. Recently viewed 0 Save Search. Oxford Textbook of Critical Care 2 ed. Read More. Your current browser may not support copying via this button.

Subscriber sign in You could not be signed in, please check and try again. Username Please enter your Username. Password Please enter your Password. Forgot password? Don't have an account? Sign in via your Institution. You could not be signed in, please check and try again. Sign in with your library card Please enter your library card number. Disclaimer Oxford University Press makes no representation, express or implied, that the drug dosages in this book are correct. Top Next Introduction Aspiration is defined as the inhalation of oropharyngeal or gastric contents into the larynx and lower respiratory tract.

Top Previous Next Clinical syndromes Aspiration pneumonitis Pathophysiology The term aspiration pneumonitis refers to the aspiration of substances that are toxic to the lower airways, independent of bacterial infection. Clinical features and diagnosis The diagnosis of acid pneumonitis is usually presumptive.

Aspiration pneumonia Pathophysiology Aspiration pneumonia develops after the inhalation of colonized oropharyngeal material. This can cause blockage of the airways and inflammation and infection of the lungs. It is more likely if there is a problem with the normal swallowing or gag reflexes. Symptoms may include coughing while eating, wheezing and shortness of breath. Toddlers and the elderly tend to aspirate more commonly, as do people who have had a stroke or brain injury, or who have other neurologic conditions.

The outcome after aspirating depends on the substance aspirated, the age of the person affected and the presence of complications following the aspiration. This condition tends to be more common among toddlers and the elderly.