Respiratory, GI and Liver Revision Flashcards
What is the normal blood pH range?
7.35-7.45. Above 7.45= alkalosis. Below 7.35= Acidosis. Outside 6.8 and 7.7=cell death
What are the possible causes of respiratory acidosis (hypoventilation Pco2 >45mmHg; pH <7.35).
Impaired lung function such as chronic bronchitis, CF, emphysema= impaired gas exchange or alveolar ventilation.
Impaired ventilator movement: paralysed respiratory muscles, chest injury, extreme obesity.
Narcotic or barbiturate overdose or injury to brain stem: depression of respiratory centres, resulting in hypoventilation and respiratory arrest.
What are the possible causes of respiratory alkalosis (hypoventilation PCo2 <35mmHg, pH >7.45))
Strong emotions- pain, fear, panic attack.
Hypoxemia: Asthma, pneumonia, high altitude, represents efforts to raise P02 at the expense of excessive Co2 excretion
Brain tumour or injury: abnormal respiratory controls
What are the possible causes of metabolic acidosis? (HCO2 <22, PH <7.35)
Severe diarrhoea: bicarb rich intestinal and pancreatic secretions rushed through the digestive tract before their solutes can be reabsorbed; bicarbonate ions are replaced by renal mechanisms that generate new bicarb ions.
Renal disease: failure of kidneys to rid body of acids formed by normal metabolic processes
Untreated diabetes mellitus: lack of insulin or inability of tissue cells to respond to insulin, resulting in inability to use glucose; fats are used as primary energy fuel, and KA occurs
Starvation: lack of dietary nutrients for cellular fuels; body proteins and fat reserves are used for energy- both yield acidic metabolites as they are broken down for energy
Excess alcohol ingestion: results in excess acids in blood
Metabolic alkalosis (HCo2 >26, pH >7.45).
Vomiting or gastric suctioning: loss of stomach HCL requires that H- be withdrawn from blood to replace stomach acid: thus H+ decreases and HC02 increases.
Selected diuretics: K+ depletion and H20 loss. Low K+ directly stimulates tubule cells to secrete H+. Reduced blood volume elicits the renin-angiotensin-aldosterone mechanism, which stimulates Na+ reabsorption and H+ secretion.
Ingestion of excessive sodium bicarb (antacid): bicarb moves easily into ECF, where it enhances natural alkaline reserve
Excess aldosterone (eg adrenal tumours)- promotes excessive reabsorption of Na+, which pulls increased amount of H+ into urine. Hypovolemia promotes the same relative effect because aldosterone secretion is increased to enhance Na+ and H20 reabsorption.
What are restrictive defects?
Those that decrease compliance of the lungs or chest wall
What are obstructive defects?
Those that block the exchange of air to and from the lungs
What are some ventilator function tests?
Spirometer; FEv1 (the forced expiratory volume in one second- the normal value for this is 80%); Forced Vital Capacity- the maximal amount of air that can be expired
What is COPD?
Chronic Obstructive Pulmonary Disease- recurrent chronic productive cough for min of 3 months over the past 2 years; characterised by progressive development of airflow limitation, that is not fully reversible and destruction of the lung parenchyma. Airflow limitation is progressive and associated with an inflammatory response of the lung to noxious particles or gases
What is asthma?
A chronic inflammatory disorder of the airways characterised by reversible airflow obstruction and resulting in cough, wheeze, chest tightness and SOB
What is emphysema?
Decrease of elastic recall, destruction of alveolar walls produce dilated air spaces, less surface area for gas exchange, unsupported airways tend to collapse on expiration, obstruction small bronchioles, air trapping, exertion dyspnoea, weight loss, accessory muscle breathing
What happens during an asthma attack?
Bronchial hyperactivity (abnormal sensitivity to normal stimuli by an antigen). The smooth muscle cells in the bronchi constricts, the airways become inflamed (oedema) and swollen, increase in mucous production to produce mucus plugs. Breathing becomes difficult (dyspnoea), turbulent air produces a wheeze, SOB, chest tightness, dry, irritating cough
What is the management of obstructive lung disorder?
Nutritional intervention- chronic resp disease increases calorie required due to WOB; drugs- bronchodilators (short and long-acting), corticosteroids, antibiotics for infections, flu vac; pressured metered dose inhalers, nebs, ventilators, o2 therapy, self-management
What are the acquired GI disorders?
Gastritis, peptic ulcers, oesophageal ulcers, gastric ulcers, duodenal ulcers, ulcerative colitis, diverticulitis, polyps, cancer, adhesions, hernias
What is gastritis?
Inflammation of the gastric mucosa. May be acute or chronic, erosive or non-erosive. Erosive does not cause significant inflammation but can wear away the stomach lining- bleeding, erosions, ulcers.
What is the most common cause of erosive gastritis?
NSAIDS- eg aspirin and ibuprofen. Other agents include alcohol, cocaine, radiation, burns, major surgery or critical illness (stress induced).
What is the most common cause of non-erosive gastritis?
Helicobacter pylori (H.pylori) infection- infect the stomach lining.
What are the diagnostic tests for gastritis?
Endoscopy with a biopsy of the stomach. Other tests may include upper GI series: barium, xray to show changes in the stomach lining such as erosions of ulcers; Blood tests: anemia may be a sign of chronic bleeding in the stomach; stool test: presence of blood in the stool (melena); tests for H.pylori infection
What does the treatment for Gastritis include?
Medications that reduce the amount of stomach acid or treat cause including: Antacids, H2 Blockers, proton pump inhibitors, reduce dose of NSAIDs/switch to other class of pain meds, treat H.pylori infection.
