Oxygenation, Pneumonia, Sleep Apnea Notes

Vocabulary flashcards covering key terms from respiratory anatomy, gas exchange, pneumonia, and sleep apnea as presented in the lecture notes.

Parietal pleura

Lining that covers the chest wall and is part of the pleural membranes surrounding the lungs.

Visceral pleura

Membrane that encases the lungs and covers their surface.

Pleural space

The potential space between the parietal and visceral pleura where membranes slide during respiration.

Alveolar unit

Functional gas exchange unit, consisting of alveoli and surrounding pulmonary capillaries.

Ventilation

Process of moving air into and out of the lungs (inhalation and exhalation).

Inspiration

Active phase of ventilation involving diaphragmatic and intercostal muscle contraction to draw air in.

Expiration

Usually passive phase of ventilation during which air leaves the lungs due to elastic recoil.

Diaphragm

Primary muscle of inspiration that increases thoracic cavity volume when it contracts.

Intercostal muscles

Muscles between the ribs that help elevate the chest during inspiration.

Scalene muscles

Accessory inspiratory muscles that lift the first and second ribs to enlarge the chest.

Intrathoracic pressure

Pressure within the thoracic cavity; decreases during inspiration, facilitating air inflow.

Air flow direction (pressure gradient)

Air moves from higher atmospheric pressure to lower intrathoracic pressure during inspiration.

Dead space

Portions of the respiratory system where air is ventilated but gas exchange does not occur.

Physiologic dead-space air

The portion of each breath that does not participate in gas exchange (around 150 ml in the conducting airways).

Surfactant

Phospholipoprotein secreted by type II pneumocytes that lowers alveolar surface tension, increases compliance, and prevents alveolar collapse.

Compliance

Ease of lung/chest wall expansion; high means easy inflation, low means stiff lungs.

Atelectasis

Collapse or closure of alveoli leading to reduced gas exchange.

Asthma

Chronic inflammatory airway disease with episodic reversible airway obstruction and mucus plugging.

Work of breathing

Effort required to breathe; increases with disease, lower compliance, or obstructed airways.

Central respiratory center

Brainstem (medulla and pons) that generates and coordinates breathing; cortex provides voluntary control.

Medulla

Brainstem region that regulates rhythmic breathing and basic ventilatory pattern.

Pons

Brainstem region that modulates and coordinates breathing patterns.

Cortex

Cerebral region enabling voluntary control of breathing.

Central chemoreceptors

Receptors in the brain that sense H+ and CO2 in CSF to regulate ventilation; less responsive to chronically high H+.

Peripheral chemoreceptors

Aortic and carotid bodies that are highly sensitive to PaO2; drive ventilation when PaO2 falls.

Irritant receptors

Lung receptors that trigger bronchoconstriction and increased respiratory rate in response to irritants.

Stretch receptors

Airway receptors that respond to stretch and can decrease ventilatory rate and volume.

Juxta-pulmonary capillary receptors

Receptors sensitive to pulmonary capillary pressure; can increase respiratory rate with high pressure.

Autonomic control of airway caliber

Sympathetic causes bronchodilation; parasympathetic (vagus) causes bronchoconstriction.

Nasal filtration

Nasal hairs filter particles larger than about 5 micrometers as the first defense in respiration.

Muco-ciliary clearance

Cilia move mucus and trapped particles out of the airways; traps particles 1–5 μm.

Ciliary impairment

Diminished ciliary function due to smoking, dehydration, high oxygen, infection, anesthetics, or certain drugs.

Alveolar macrophage

Primary immune defense in the alveoli; phagocytes that remove inhaled particles; impaired by smoking.

Cough reflex

Protective reflex that clears substances from the large airways.

Oxyhemoglobin saturation (O2 Sat.)

Percentage of hemoglobin bound with oxygen; normally ~96–100%.

PaO2

Partial pressure of oxygen in arterial blood; normal range ~80–100 mmHg.

SpO2

Oxygen saturation measured by pulse oximetry; reflects percent of Hb with O2.

Oxyhemoglobin association/dissociation

Process of Hb binding O2 in the lungs and releasing O2 to tissues; influenced by pH, CO2, temperature, etc.

Ventilation/Perfusion (V/Q) ratio

Ratio of air actually reaching alveoli to blood flow through the pulmonary capillaries; essential for gas exchange.

Normal V/Q ratio

Approximately 0.8 to 1.0 in healthy adults.

Shunt unit

Ventilated poorly or not at all but still perfused; very little or no gas exchange.

Dead space unit

Ventilated but not perfused alveoli; gas exchange does not occur.

Pneumonia

Infection and inflammation of lung tissue causing alveolar filling with exudate; can be bacterial, viral, fungal.

Community-acquired pneumonia (CAP)

Pneumonia acquired outside the healthcare setting or within 48 hours of hospital admission.

Hospital-acquired pneumonia (HAP)

Pneumonia occurring 48 hours or more after admission not incubating at admission.

Ventilator-associated pneumonia (VAP)

Pneumonia that develops after endotracheal intubation, typically after 48 hours.

Healthcare-associated pneumonia (HCAP)

Pneumonia in patients with recent healthcare exposure (not hospitalized at onset).

Pneumonia clinical manifestations

Fever, chills, productive cough with sputum, SOB, chest pain, crackles, consolidation on imaging.

Pneumonia complications

Respiratory failure, pleural effusion, atelectasis, bacteremia, empyema, among others.

Pneumonia vaccines

Vaccines such as pneumococcal vaccine; COVID-19 vaccine; recommended for at-risk groups.

Sleep Apnea

Sleep disorder characterized by recurrent pauses in breathing (apneas) during sleep.

Obstructive sleep apnea syndrome (OSAS)

Obstruction of the upper airway during sleep, with snoring and apneic events, causing hypoxia and arousal.

Risk factors for sleep apnea

Enlarged soft tissue structures, enlarged jaw, obesity, large neck circumference, family history.

Mechanisms of OSA

Relaxation of pharyngeal muscles leading to tongue and airway collapse; obstruction causes apnea and arousal.

Management of OSA

Weight reduction, sleep position, avoid alcohol/sedatives/tobacco; humidification; CPAP/BiPAP.

Nursing interventions for OSA in hospital

Headgear as prescribed, room near nurse’s desk, careful monitoring with pain meds and sedation.