Chapter 19 Respirations

Apnea

Absence of breathing for several seconds Associated factors are Respiratory distress, obstructive sleep apnea.

Assessment of Respirations

Assessment of respirations always includes measurement of the breathing rate, depth, and rhythm, and it routinely includes measurement of levels of oxygen saturation by pulse oximetry. Before assessing respirations, the nurse needs to be aware of the patient's normal respiratory pattern, how the patient's health status affects respirations, any medications that may affect respirations, and the impact of cardiovascular system factors on the respiratory system. The assessment of respirations begins with observing the chest and abdominal movements for effort and symmetry (Skill 19-3). The rate is assessed by counting the number of breaths taken per minute. One inspiration and expiration cycle is counted as one breath. On inspiration, the rib cage raises and the diaphragm lowers, allowing air to fill the lungs. The muscles relax in expiration, causing the rib cage to lower and the diaphragm to rise, forcing the air out of the lungs. A complete respiratory assessment, including abnormal respiratory sounds, is described in Chapter 20.

Planning

Goals related to respiratory rate assessment focus on ensuring adequate level of oxygen to meet the physiologic needs of the body. Examples are: • Patient will exhibit regular breathing pattern with assistance from ventilator while in the ICU. • Patient will be free of signs of hypoxia with ABGs within the patient's normal range within 8 hours of admission. • Patient will demonstrate ability to complete activities of daily living with no increase in dyspnea before discharge. • Patient will be able to cough up secretions within 24 hours of beginning respiratory treatments.

Implementation and Evaluation

Changes in respiratory rate and rhythm are a sign of many physiologic and emotional disorders. Interventions for the underlying disorder should improve an altered respiratory pattern, and they include positioning, supplemental oxygen, suctioning, and medications such as bronchodilators. A watch with a sweep second hand is needed to count respirations for 1 minute. To ensure an accurate measurement, respirations are counted when the patient is unaware of the procedure to prevent voluntary control of breathing by the patient. If respirations are shallow and slow, a stethoscope may be needed to auscultate breath sounds. Respirations can be palpated by placing a hand on the lower chest or abdomen and counting the breaths felt. An apnea monitor is used to monitor chest movement with leads that are placed on the chest and set off an alarm according to preset parameters. Apnea monitors are used for ill or preterm infants, as well as adults who may have periods of apnea, especially during sleep. Apnea monitors may be used in the home or during hospital admissions. Evaluation of respiration must be done in conjunction with the other vital signs obtained and the medical status of the patient. A respiratory rate significantly above or below normal, any notable changes in pattern, and inadequate oxygenation must be reported to the PCP. Appropriate follow-up to prescribed interventions, such as evaluating the response to oxygen therapy, medications, and positioning, is essential.

orthopnea

Difficulty breathing experienced in positions other than sitting or standing

hypercapnia

High levels of carbon dioxide.

Factors Affecting Respiration

Inspiration and expiration should be smooth and without conscious effort. Environmental or physiologic factors may cause increases or decreases in respiratory rate or depth. Factors that affect respiratory rate and depth include age, exercise, respiratory and cardiovascular disease, alterations in fluid and electrolyte balance acid-base disturbances, medications, pain, and emotions. • Age: Respiratory rate decreases with age through late adolescence, when it stabilizes. • Exercise: Respiratory rate and depth increase with exercise. • Illness processes: Cardiovascular disease and hematologic disorders such as anemia cause an increased respiratory rate. Sickle cell disease reduces the ability of hemoglobin to carry oxygen, resulting in increased respiratory rate and depth. Respiratory diseases can be manifested by difficulty breathing, use of accessory muscles, increased rate, and shallower depth. Smoking alters airways, resulting in an increased rate. • Acid-base balance: Acidosis results in increased rate and depth of respirations in an attempt to rid the body of excess carbon dioxide. Alkalosis results in decreased respiratory rate as the body tries to retain carbon dioxide. • Medications: Some medications, such as narcotics and general anesthesia, slow respirations. Alternatively, drugs such as amphetamines and cocaine increase respirations. Bronchodilators slow the respiratory rate by dilating the airways. • Pain: Acute pain increases respiratory rate while decreasing respiratory depth. • Emotions: Fear or anxiety can cause increased respiratory rate and decreased depth.

Arterial Blood Gases

Measurement of arterial blood gases (ABGs) is a way of assessing the respiratory component of acid-base balance and the adequacy of oxygenation. ABG values include the carbon dioxide level and pH, and they are used to determine the need for and response to treatment. (Refer to Chapter 39 for a detailed discussion of ABG results.) Arterial blood is used for assessment because values for venous blood gases are highly variable, depending on the metabolic demands of the tissues that empty into the vein where the sample is drawn. ABG studies are used to establish baseline values, identify respiratory disorders, and evaluate the effectiveness of interventions. ABG samples also are drawn to monitor patients who are critically ill.

Oxygen Saturation

Measurement of respiratory rate is not a measurement of how much oxygen actually enters the bloodstream. The SpO2, which reflects the percentage of hemoglobin that combines with oxygen, normally is 95% to 100%. Factors that affect the SpO2 include lung disease, decreased circulation, and hypotension. Cyanosis , bluish discoloration of the skin and mucous membranes, results from decreased oxygen levels in arterial blood. The level of consciousness is affected by changes in oxygen levels. Patients displaying signs of reduced oxygen require additional assessment of mental status, activity tolerance, and measurement of oxygen saturation. Measurement of oxygen saturation is performed noninvasively and painlessly by means of pulse oximetry. A pulse oximeter is a small device that is clipped to a fingertip, a toe, the nose, or an earlobe. The most desirable site is the fingertip; alternate sites are used only when use of the fingertip is not appropriate. The device has an electronic display for oxygen saturation and pulse rate. Infrared light from one side of the sensor is read by a photo detector on the other side, which measures the amount of light absorbed by oxygenated and deoxygenated hemoglobin. Cold or injury to extremities, peripheral edema, and jaundice interfere with obtaining an accurate value. Movement at the site of sensor attachment, shivering, and some types of nail polish also affect the accuracy of the reading. Skill 19-4 explains how to measure oxygen saturation. The role of oxygen saturation readings in identifying changes in patient status is critical. It is important to maintain vigilance in monitoring the patient's clinical condition, especially when abnormalities in vital signs or changes in vital sign measurements are present; any significant change must be reported promptly.

eupnea

Normal respiration with a normal rate and depth for the patient's age

Kussmaul's breathing

Respirations abnormally deep, regular, and increased in rate. Associated factors are Diabetic ketoacidosis.

Biot's breathing

Respirations abnormally shallow for two or three breaths, followed by irregular period of apnea. Associated factors are Meningitis, severe brain injury.

Nursing Diagnosis

Respiratory assessment data are a defining characteristic of many nursing diagnoses, including: • Ineffective Breathing Pattern related to increased intracranial pressure from traumatic head injury as evidenced by hypoventilation • Impaired Gas Exchange related to alveolar changes as evidenced by oxygen saturation of 89% on room air • Activity Intolerance related to decreased oxygenation levels as evidenced by dyspnea on exertion • Ineffective Airway Clearance related to thick secretions as evidenced by inability to clear sputum with cough

Physiology and Regulation of Breathing and Ventilation

Respiratory centers in the medulla and pons are stimulated by impulses from chemoreceptors located throughout the body. Chemoreceptors located in the aortic arch and carotid arteries are especially sensitive to low oxygen levels in the blood. Receptors in the medulla are especially sensitive to high levels of carbon dioxide and changes in pH. Additional stretch receptors in the lungs and receptors in muscles and joints provide input to the medulla and pons. Respiratory rate and depth change on the basis of input from these receptors, but the strongest respiratory stimulant is an increase in carbon dioxide, which causes an increase in respiratory rate and depth. The cerebral cortex of the brain allows voluntary control of breathing, for example, when singing.

Cheyne-Stokes respirations

Rhythmic respirations, going from very deep to very shallow or apneic periods. Associated factors are Heart failure, renal failure, drug overdose, increased intracranial pressure, impending death.

Safe Practice Alert

Signs of respiratory distress include the use of accessory muscles of the chest and neck and/or an exaggerated effort to breathe. Children and infants may exhibit nasal flaring or sternal retractions if they are having trouble breathing.

oxygen saturation

amount of oxygen in the arterial blood

Tachypnea

an increase in respiratory rate to more than 24 BPM in the adult. Any condition that causes an increased need for oxygen or an increased metabolic rate (e.g., high altitude or fever) or an increase in carbon dioxide levels (e.g., chronic lung disease) will cause tachypnea.

Cyanosis

bluish discoloration of the skin and mucous membranes, results from decreased oxygen levels in arterial blood.

Bradypnea

is a decrease in respiratory rate to less than 10 BPM in the adult. Bradypnea can be caused by medications, especially opioids, metabolic disorders, or brain injury.

Hypoventilation

is characterized by shallow respirations; it is associated with drug overdose and obesity, as well as COPD and cervical spine injury.

Dyspnea

is difficult, labored breathing, usually with a rapid, shallow pattern, that may be painful. Anxiety usually is present as well. Accessory muscles in the chest and neck are used in dyspneic breathing. Many patients experiencing dyspnea find it easier to breath in an upright position, in which gravity lowers the organs of the abdomen away from the diaphragm, giving the diaphragm room to expand downward as the lungs expand with inspiration.

Hyperventilation

is exhibited by deep, rapid respirations; it is often caused by stress or anxiety. Different respiratory patterns have characteristic rates, rhythms, and depths.

hypoxemia

low oxygen levels in the blood

respiration

the act of breathing. Breathing (pulmonary ventilation) is the movement of air into and out of the lungs: Inspiration (inhalation) is the act of breathing in, and expiration (exhalation) is the act of breathing out. To survive, cells of the body must receive enough oxygen to meet metabolic requirements and release carbon dioxide. The purpose of respiration is to allow the exchange of oxygen and carbon dioxide among the alveoli, circulating blood, and tissue cells. Several physiologic events work together to meet the gas exchange needs of the body. Nurses assess for signs of changes in gas exchange. The process that is measured as a vital sign is pulmonary ventilation, or respirations. A normal respiratory rate is 12 to 20 BPM for an adult.