Respiratory Failure Dr AbdulMonim Batiha Associate Professor Critical

Respiratory Failure Dr. Abdul-Monim Batiha Associate Professor Critical Care Nursing

Introduction: • Acute respiratory failure remains a major cause of morbidity and mortality in the intensive care setting, despite the technological advances in diagnosis, monitoring, and management • 44% of patients diagnosed with acute respiratory failure who required admission to the ICU died in the hospital.

Definition • Respiratory failure is inadequate gas exchange by the respiratory system, with the result that levels of be maintained within their norarterial oxygen, carbon dioxide or both cannot mal ranges. A drop in blood oxygenation is known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia. • It is one of the most common problem seen in critical care, with a survival rate of about 55%

• The normal reference values are: oxygen Pa. O 2 more than 80 mm. Hg , and carbon dioxide Pa. CO 2 lesser than 45 mm. Hg. • Classification into type I or type II relates to the absence or presence of hypercapnia respectively.

Types: • Type 1 respiratory failure: Is defined as hypoxemia without hypercapnia, and indeed the Pa. CO 2 may be normal or low. It is typically caused by a ventilation/perfusion (V/Q) mismatch; the volume of air flowing in and out of the lungs is not matched with the flow of blood to the lungs.

The basic defect in type 1 respiratory failure is failure of oxygenation characterized by: • Pa. O 2 decreased (< 60 mm. Hg (8. 0 k. Pa)) • Pa. CO 2 normal or decreased (<50 mm. Hg (6. 7 k. Pa))

This type of respiratory failure is caused by conditions that affect oxygenation such as: • Low ambient oxygen (e. g. at high altitude) • Ventilation-perfusion mismatch (parts of the lung receive oxygen but not enough blood to absorb it, e. g. pulmonary embolism)

This type of respiratory failure is caused by conditions that affect oxygenation such as (cont’d): • Alveolar hypoventilation (decreased minute volume due to reduced respiratory muscle activity, e. g. in acute neuromuscular disease); this form can also cause type 2 respiratory failure if severe. • Respiratory minute volume (or minute ventilation or expired minute volume) is the volume of gas inhaled (inhaled minute volume) or exhaled (exhaled minute volume) from a person's lungs per minute.

This type of respiratory failure is caused by conditions that affect oxygenation such as (cont’d): • Diffusion problem (oxygen cannot enter the capillaries due to parenchymal disease, e. g. in pneumonia or ARDS) • Shunt (oxygenated blood mixes with nonoxygenated blood from the venous system, e. g. right-to-left shunt) (A right-to-left shunt is a cardiac shunt which allows blood to flow from the right heart to the left heart)

(A right-to-left shunt is a cardiac shunt which allows blood to flow from the right heart to the left heart)

Type 2 RF • Hypoxemia (Pa. O 2 <60 mm. Hg ) with hypercapnia (Pa. CO 2 (> 50 mm. Hg ).

The basic defect in type 2 respiratory failure is characterized by: • Pa. O 2 decreased (< 60 mm. Hg (8. 0 k. Pa)) • Pa. CO 2 increased (> 50 mm. Hg (6. 7 k. Pa)) • p. H decreased

• Type 2 respiratory failure is caused by inadequate alveolar ventilation; both oxygen and carbon dioxide are affected. Defined as the build up of carbon dioxide levels (Pa. CO 2) that has been generated by the body but cannot be eliminated

Cause of type 2 RF • Increased airways resistance (chronic obstructive pulmonary disease, asthma, suffocation) • Reduced breathing effort (drug effects, brain stem lesion, extreme obesity)

Cause of type 2 RF (Cont’d) • A decrease in the area of the lung available for gas exchange (such as in chronic bronchitis) • Neuromuscular problems (Guillain-Barré syndrome, myasthenia gravis, motor neurone disease) • Deformed (kyphoscoliosis), rigid (ankylosing spondylitis), or flail chest.

• Kyphoscoliosis describes an abnormal curvature of the spine in both a coronal and sagittal plane. It is a combination of kyphosis and scoliosis.

• Ankylosing spondylitis (AS, from Greek ankylos, fused; spondylos, vertebra; -itis, inflammation), is a chronic inflammatory disease of the axial skeleton, with variable involvement of peripheral joints and nonarticular structures.

• Flail chest or paradoxical breathing is a life-threatening medical condition that occurs when a segment of the rib cage breaks under extreme stress and becomes detached from the rest of the chest wall. It occurs when multiple adjacent ribs are broken in multiple places, separating a segment, so a part of the chest wall moves independently.

Assessment • History • A complete medical and social history should be obtained from the patient or a family member to determine the patient’s baseline respiratory status on admission.

Signs and symptoms of hypoxemia • The classic symptom of hypoxemia is dyspnea, although this may be completely absent in ventilatory failure resulting from depression of the respiratory center. • Cyanosis, • Restlessness, • Confusion, • Anxiety, • Delirium, • Tachypnea, • Tachycardia, • Hypertension, • Cardiac dysrhythmias, • Tremor.

Diagnostic Tests: • Arterial Blood Gas Monitoring. • Chest X-ray. • Pulmonary Function Test.

Laboratory investigations: • Blood gases • HCT, Hb, WBC. • Electrolytes

Medical managment Is aimed at • Treating the underlying cause • Promoting adequate gas exchange • Correcting acidosis, initiating nutrition support, preventing complications

Oxygenation • Supplemental oxygen • To correct hypoxemia(maintain arterial hemoglobin o 2 saturation sao 2 at greater than 9 -%, supplying tissue needs but not producing hypercapnea or oxygen toxicity

Oxygenation • supplemental oxygen alone is ineffective. In this situation , positive pressure is necessary to open collapsed alveoli and facilitate their participation in gas exchange • Positive pressure may be delivered noninvasively via a mask , or invasively via endotracheal tube or tracheostomy tube

Ventilation • The use of noninvasive and invasive mechanical ventilation depending on the underlying cause and the severity of the acute respiratory failure, the patient may be initially treated with noninvasive ventilation. however, patients with ph less than 7. 25 at initial presentation may be more likely to need invasive mechanical ventilation.

Ventilation • The selection of ventilatory mode and settings depends on the patient’s underlying condition, severity of respiratory failure, and body size. the patient is usually started on volume ventilation in the assistcontrol mode. In the patient with chronic hypercapnea the settings should be adjusted to keep ABG values within the parameters that the patient should maintain after extubation

pharmacology • Mucolytics to help liquify secretions, which facilitates their removal • Bronchodilators, such as xanthines, B 2 agonists, and anticholinergic agents, aid in smooth muscle relaxation and are of particular benefit to patients with airflow limitations • Steroids to decrease airway inflammation and enhance the effects of the B 2 agonists

pharmacology • Sedation to assist with maintaining adequate ventilation, to comfort the patient and decrease the work of breathing, particularly if the patient is fighting the ventilator • Analgesics to control pain • Neuromuscular relaxants to facilitate optimal ventilation to decrease o 2 consumption in the severly compromised patient

Acidosis • Hypoxemia causes impaired tissue perfusion, which leads to the production of lactic acid and the development of metabolic acidosis • Impaired ventilation leads to the accumulation of carbon dioxide (co 2) and the development of respiratory acidosis/. • Once the patint is adequately oxygenated and ventilated, the acidosis should correct itself • The use of sodium bicarbonate to correct the acidosis has been shown to be of minimal benefit to the patient, although it may still be used if the acidosis persists or is severe(ph less than 7. 2

Nutritional support • The goal is to meet the overall nutritional needs of the patient while avoiding overfeeding in order to prevent nutrition delivery –related complications and to improve patient outcome • Failure to provide the patient with adequate nutrition support results in the development of malnutrition. • Both malnutrition and overfeeding can interfere with the performance of the pulmonary system, perpetuating ARF.

• Malnutrition decreases the patient’s ventilatory drive and muscle strength whereas overfeeding increases co 2 production, which then increases the patient’s ventilatory demand, resulting in respiratory muscle fatigue • The enteral route is the preferred method of nutrition administeration.

• If a patient cannot tolerate enteral feedings or cannot receive enough nutrients enterally, the patient will be started on parenteral nutrition. • Because the parenteral route is associated with a higher rate of complications, the goal is to switch to enteral feedings as soon as the patient can tolerate them. • Nutrition support should be initiated before third day of mechanical ventilation for the well nourished patient and within 24 hours for the malnourished patient.

• Nursing Diagnosis: Ineffective breathing pattern related to decreased lung compliance as evidenced by dyspnea, tachypnea and abnormal ABGs • Long term goals • Client will experience adequate perfusion as evidenced by normal arterial blood gas levels* normal for client, decreased tachycardia & dyspnea

Interventions • Monitor pulse oximetry for oxygen saturation and notify for < 90% • Oximetry readings of 90 correlate with Pa. O 2 of 60. Levels below this do not allow for adequate perfusion to tissues and vital organs.

• Monitor ABGs for changes and trends. • Provides information on acid/base status and oxygenation. • Must consider both oxygenation and ventilation.

• Maintain HOB elevation at least 30 degrees. • Elevating HOB decreases risk of aspiration and facilitates lung expansion.

• Monitor ECG changes in cardiac rhythm, dysrhythmias, or conduction defects. • Hypoxia can result in life-threatening dysrhythmias that require emergent treatments.

Promoting secretion clearance Providing adequate systemic hydration Humidifying supplemental oxygen Coughing and suctioning Postural drainage & Chest percussion and vibration have been found to be of little benefit in the critically ill patient • Deep brearhing while the head of the bed elevated at least 30 degrees • Semirecumbent position decrease the risk of aspiration and inhibit the development of nosocomial pneumonia • •

Rotation therapy • Frequent positioning (at least every 2 hours) or continuous latera

Once the patient is extubated • Deep breathing( involves having the patient take a deep breath and hold it for approximately 3 seconds or longer • Incentuive spirometry(involves having the patient take at least 10 deep, effective breaths per hour using an incentive spirometer • These actions help to prevent atelectasis and to reexpand any collapsed lung tissue

Once the patient is extubated • The chest should be auscultated during inflation to ensure that all dependent parts of the lung are well ventilated and to help the patient understand the depth of breath necessary for optimal effect • Coughing should be avoided unless secretions are present because it promotes collapse of the smaller airways

Providing patient education • The patient and family should be taught about acute respiratory failure , its etiologies and its treatment, the interventions necessary for preventing the recurrence of the precepitating disorder • The patient who smokes should be encouraged to stop smoking and be referred to a smoking cessation program • In addition , the importance of precipitating in a pulmonary rehabilitation program