Respiratory Anatomy and Tests Flashcards
Respiratory System (2 parts)
- Upper respiratory tract: nose, nasal passages, pharynx, and larynx.
- Lower respiratory tract: trachea, bronchi, their branches or bronchioles, and alveoli.
Pharinx & Larynx
- Pharinx: from the upper end of the esophagus to the soft palate of the mouth and the posterior aspect of the nasal cavity.
- Larynx (Adam’s apple): is a section of the pharynx that acts as a cartilaginous sphincter device situated in the lower part of the pharynx.
Aspiration to the lungs
Happens when the muscles that control the action of the larynx don’t work:
- Vagus nerve can become inactive after neuro events (i.e. CVA or general anaesthesia)
- When trying to speak and eat at the same time.
Pulmonary circulation
Pulmonary artery carries deoxygenated blood from heart to lungs.
Pulmonary vein carries oxygenated blood from lungs to the LA, then pumped via LV.
Ribs movement
During inhalation (negative pressure): up and out.
During exhalation (positive pressure): down and in.
Top ribs: pump handle.
Lower ribs: bucket handle.
Surface Marking for the Respiratory System
- Apices: 2.5 cm sup to clavicles.
- Medial border of R lung: sternoclavicular joint to xiphisternum.
- Extent of inf border R lung: xiphisternum to 6th rib in midclavicular line; 8th rib in midaxillary line; 10th rib from midscapular line (with arm at rest by the side)
- Extent of med border L lung: sternoclavicular joint to mid sternum and then deviates for heart (cardiac notch) at level of 5 and 6 costal cartilages, then similar to R lung.
- Bifurcation of trachea: sternal notch anteriorly; level of 5th Tx vertebra posteriorly.
Breathing Patterns
Normal resting rate of ventilations (inhalation+exhalation) is 12-20 breaths/min (bpm) = EUPNEA
Bradypnea = below 10 bpm
Tachypnea = above 24 bpm
Apnea = cessation of breathing
*In newborn 25-50 bpm is normal and reduces with age. 3yo 20-30 bpm; 16yo 15-20 bpm.
Abnormal Breathing Patterns
Cheyne-Stokes breathing: irregular exhalation and inhalation with some deep breaths and some shallow. Associated with heart failure and patients that are dying.
Ataxic breathing: irregular depth of breaths. Associated with cerebellar dysfunction.
Apneustic breathing: prolonged inhalation phase. Associated with brain damage.
Lung Capacities (definitions and volume of air in normal adult males)
- Tidal Volume (TV): air inhaled/exhaled, each breath, in normal, quiet breathing. 500 mL (7-8% TLC)
- Inspiratory Reserve Volume (IRV): extra air that can be inhaled over TV. 2500 mL (±60% TLC)
- Expiratory Reserve Volume (ERV): extra air that can be exhaled over TV. 1000 mL (±20% TLC)
- Residual Volume (RV): air that stays in lungs after forced expiration. 1500 mL (±20% TLC)
- Inspiratory Capacity (IC): TV + IRV. 3000 mL
- Functional Residual Capacity (FRC): amount of gas left in lungs after normal exhalation. 2500 mL (±40% TLC)
- Vital Capacity (VC) or Forced Vital Capacity (FVC): IRV + TV + ERV - max amount of air exhaled after a maximal inhalation. 4000 mL
- Forced Expiratory Volume in 1 sec (FEV1): volume of air that is forcibly expired after max inspiration in 1”, usually 80% of VC if healthy. 3200 mL
- Total Lung Capacity (TLC) = VC+RV: all lung volumes added together, i.e. total amount of air after a deep inspiration. 5500 mL
- Minute Ventilation (V): TV x rate of ventilation. 500x15=7500 mL
Gaseous exchange concepts
- Ventilation / external respiration: air into lungs and CO2 from lungs.
- True respiration / internal respiration: exchange of O2 within the cells.
- Diffusion: process by which O2 is carried into the red blood cells from the alveoli.
- Perfusion: blood in the pulmonary vessels that supplies the lung tissue.
- Ventilation-perfusion ratio or quotient (V/Q ratio): in healthy adult is 0.8 (80%). Relationship from perfusion in the lung and lung capacity to diffuse O2 into the blood. Changes in the ratio enable you to evaluate the need to administer O2.
Acidosis / Alkalosis
When lungs don’t function fully, the CO2 is not removed, and because it is acid, it causes a drop in the normal pH of the lung causing acute respiratory acidosis.
If a patient hyperventilates, this can cause an increase in the pH level, leading to acute respiratory alkalosis.
Muscles of ventilation
- Quiet or resting inhalation: diaphragm and external intercostal muscles.
- Accessory muscles for inhalation: sternocleidomastoids, scalenes, serratus anterior, pectoralis major and minor, trapezius, and erector spinae.
- Quiet or resting exhalation: diaphragm and internal intercostal muscles.
- Accessory muscles for exhalation: abdominals (especially rectus abdomini).
Diaphragm
- Main muscle of inhalation.
- Dome-shaped, separates abdominal and thoracic cavities. Attaches to the xiphoid process of the sternum, the internal aspects of the lower 4 ribs, and the bodies of L1-3.
- The esophagus, aorta, and sup vena cava pass through.
- Phrenic nerve innervates the diaphragm. It arises from Cx root levels 3, 4, and 5.
- Patients with some spinal cord injuries might only be able to do diaphragmatic breathing.
- Up to 2/3 of VC is created by flattening the diaphragm. In babies, diaphragm is responsible for most of the ventilation.
- Parietal pleura is attached to it so that when the diaphragm contracts, it pulls the pleura with it and assists with the increased negative pressure.
Tests for Respiratory Function
- Subjective: those learn directly from the patient.
- Objective: include those signs and symptoms associated with respiratory conditions than the PT can observe:> Excursion: measurement of chest expansion. In healthy, young adult 20-30 yo, is approx 8.5 cm @ xiphoid level. This measurement can be misleading in patients with advanced stages of COPD because of hyperinflated thoracic cavity.> Intercostal indrawing: of the spaces between the ribs, occurs in individuals with marked resistance to airflow during inhalation. Is the result of an increased negative pressure in the Tx cavity.> Breath sounds: detected using auscultation techniques.
Abnormal breath sounds
Detected following systemic pattern (6 different spots doing figure 2 between scapulas):
- Tracheal sounds heard over lung tissue areas that may be due to pneumonia when fluid is present in the lungs.
- Absence of any sound may occur in cases of pleural effusion, collapsed lung, or pneumothorax. In cases of asthma episodes, clinicians may not hear any breath sounds because of the obstruction of the bronchi and bronchioles.
- Unusual sounds over the lungs a.k.a. adventitious or extra sounds:> Wheezing and rhonchi = obstruction of bronchi and bronchioles.> Crepitations and crackles: detected on inhalation and are short-duration sounds resulting from opening and closed airways.> Pleural rub or friction rub: heard as a squeak on both inhalation and exhalation. Is the result of either rubbing together of inflamed pleura or presence of a neoplasm in the pleura.
- If whisper sounds can be heard = disease active causing hardening or consolidation of the lung tissue. Otherwise, voice can’t be heard clearly.
