430 exam 2

• Type 1 Alveolar Cells:

  • Make up 90% of the total alveolar surface
  • Chief structural cells of the alveolar wall
  • Play a major role in the gas-blood barrier and gas exchange
  • Thin and susceptible to injury
  • Inflamed when exposed to inhaled toxins
• Type 2 Alveolar Cells:

  • Produce, store, and secrete pulmonary surfactant
  • After injury, type 2 cells rapidly divide to line the surface and later differentiate into type 1 cells
• Alveolar Capillary Membrane (ACM):

  • Vessels of the ACM form a network around each alveolus
  • Large enough so each red blood cell membrane touches the capillary wall, allowing for efficient gas exchange
  • Hemoglobin is brought from its normal venous blood saturation level of 75% to its arterial saturation of more than 96%
• • Ventilation: movement of air into lungs (inhalation) and out of the lungs (exhalation.) 
• • Ventilation perfusion relationships: “V/Q”, should be equally matched at ACM level for optimal gas exchange. Not the case, so normal v/q ratio is 4:5 or 0.8
• three main causes of hypoxemia: alveolar hypoventilation, ventilation - perfusion mismatch, intrapulmonary shunting
• • Hypoxic vasoconstriction: typically blood vessels in the body dilate in response to hypoxia, the pulmonary vessels constrict when PaO2 is less than 60mmhg. 
  • Occurs when portion of pulmonary capillaries perfuse un/under ventilated alveoli. 
  • Thought to be a compensatory response to limit return of unoxygenated blood to the left side of the heart. If prolonged and generalized through the lungs, pulmonary hypertension results.  
• • Lack of surfactant: Pulmonary surfactant functions to lower the surface tension of the alveoli -> stabilized the alveoli, increase lung compliance, eases the work of breathing. Disrupted  -> lungs less compliant, work of breathing increases. Severe loss results in alveolar instability and collapse and impairment of gas exchange
• • Air leak disorders: conditions that result in extra alveolar air accumulation.  
  • 2 categories:
  • Pneumothorax: accumulation of air or other gas into the pleural space
  • Barotrauma/volutrauma: result of excessive pressure in the alveoli that can lead to extreme alveolar wall stress and damage to the ACM, causing air to escape into the surrounding spaces 
• • Pulmonary embolus: a clot lodges in the pulmonary artery system, disrupting the blood flow to a region of the lungs, a massive PE occurs with the blockage of a lobar or larger artery, resulting in occlusion of the pulmonary vascular bed.
  • Pulmonary consequences: increased alveolar dead space, bronchoconstriction, compensatory shunting 
  • Hemodynamic consequences: increase in pulmonary resistance and right ventricular workload 
• Oxygen Therapy: Methods of delivery include low-flow systems and high-flow systems

  • Low-flow systems provide supplemental oxygen directly into the patient’s airway at a flow of 8 L/min or less
  • Reservoir systems incorporate a device to collect and store oxygen between breaths
  • High-flow systems deliver oxygen in an amount sufficient to meet all inspiratory volume requirements
• Oxygen Therapy Goal:

  • Ensure adequate cellular oxygenation
  • Oxygen is considered a medication and requires a physician’s order
  • Indication: Hypoxemia
  • Dose-response method: Administer the lowest possible level of oxygen that will achieve a satisfactory PaO2 or SaO2
• Oxygen Therapy Complications:

  • Oxygen toxicity
  • Carbon dioxide retention
  • Absorption atelectasis
  • Nursing management includes confirming the device is properly positioned, replacing it if dislodged, and monitoring oxygen saturation with a pulse oximeter
• Artificial Airways:

  • Types include pharyngeal airways, oropharyngeal airways, and nasopharyngeal airways
  • Endotracheal tubes (ETT) are used for short-term airway management
  • Rapid Sequence Intubation (RSI) involves several steps for intubation and post-intubation management
• Artificial Airways:

  • Tracheostomy tubes are used for long-term intubation
  • Indications include avoiding complications from oral, nasal, pharyngeal, and laryngeal intubation
  • Complications of tracheostomy tubes include displacement, bleeding, infection, and more
• Artificial Airways Nursing Management:

  • Involves humidification, cuff management, suctioning, and communication
  • Closed tracheal suction systems (CTSS) are used for suctioning
  • Passy-Muir® valve aids in communication
• Invasive Mechanical Ventilation:

  • Indications, types of ventilators, ventilator mechanics, modes of ventilation, and complications are important aspects
  • Ventilator-induced lung injury, barotrauma, volutrauma, and other complications can occur
• Invasive Mechanical Ventilation Weaning:

  • Factors for weaning, weaning methods, and nursing management during weaning are crucial
  • Synchronized intermittent mandatory ventilation (SIMV) trials and pressure support ventilation (PSV) trials are common methods
• Invasive Mechanical Ventilation Nursing Management:

  • Includes patient assessment, ventilator assessment, patient safety, and readiness to wean
  • The ABCDEF bundle is used for symptom management
• Noninvasive Ventilation:

  • Advantages, indications, and nursing management are key points
  • Close monitoring, proper mask fitting, and patient positioning are important
• Positioning Therapy:

  • Involves prone positioning and rotation therapy
  • Prone positioning helps mobilize secretions and profuse less damaged areas of the lungs
  • Rotation therapy involves turning the patient at least 40 degrees per side for at least 18 hours a day
• Pharmacology:

  • Includes bronchodilators, steroids, antibiotics, sedatives, analgesics, and neuromuscular blocking agents
• • PaO2/FIO2 ratio (PF ratio)
  • Ratio of partial pressure of oxygen in arterial blood to the fraction of inspiratory oxygen concentration 
  • Normal: greater than 286 -> lower the value = worse the lung function
• Type I: Hypoxemic Normocapnic

  • no ventilation failure- may need intubated to distribute oxygen better
  • intrapulmonary issues
• Type II: Hypoxemic Hypercapnic

  • ventilation failure- poor ventilation or severe hypoxemia
  • extrapulmonary issues
• Intrapulmonary issues --> inside the lungs & type 1 

  • Lower airways and alveoli: COPD, asthma, bronchiolitis, pneumonia, pulmonary edema, cystic fibrosis (TYPE 2)
  • Pulmonary circulation: PE
  • ACM: ARDS, inhalation of toxic gases, near-drowning
• Extrapulmonary issues --> outside the lungs & type 2

  • Brain – brain damage, anesthesia, drug OD
  • Spinal cord – Polio, ALS, injury
  • Neuromuscular – MG, MS, muscular dystrophy
  • Thorax – massive obesity, chest trauma
  • Pleura – pleural effusion, pneumothorax, malignancy 
  • Upper airways – sleep apnea, epiglottitis, tracheal obstruction 
• Alveolar hypoventilation

  • Results from extrapulmonary disorders + type 2 --> not enough oxygen is being brought into the alveoli… not enough ventilation 
  • Alveoli are normal,  just not enough for gas exchange 
  • TX: can give O2 (doesn’t correct low ventilation), control pain, demonstrate deep breathing, IS
• Ventilation/Perfusion mismatch 

  • Most common cause is partially collapsed alveoli/atelectasis or partially filled alveoli or pulmonary edema (type 1) 
  • Ventilation and blood flow are mismatched in various regions of the lung… blood flow goes by under ventilated alveoli or no blood to alveoli to pick up oxygen
  • Tx: supplemental O2
• Intrapulmonary shunting 

  • Blood goes to arterial system without ventilation because most of the alveoli are filled with fluid or collapsed. (type 1) 
  • Tx: need PEEP, BiPAP is no acidosis, minimal O2 
• ALF ABGs: 

  • PaO2 less than 60
  • PaCO2 greater than 45 
  • pH < 7.35 
• ALF Ventilation: maintain pH level

  • no acidosis: bipap or no bipap = bipap
  • if acidotic/ pH < 7.25: NIV or intubate = intubate
• ALF nur interventions- positioning

  • good lung down
  • or HOB up
• ALF nur interventions- prevent desat

  • perform procedures as needed
  • hyper oxygenate before suction
  • rest and recovery time
  • minimize oxygen consumption (limit activity, sedation, control fever)
  • monitor with pulse oximeter
• ARDS diagnosis according to the Berlin Definition:

  • Timing: within 1 week of known clinical insult or new or worsening respiratory symptoms
  • Chest imaging: bilateral opacities (fluids) not fully explained by effusions, lobar/lung collapse, or nodules
  • Origin of edema: respiratory failure not fully explained by heart failure or fluid overload
• Classification of ARDS dependent on oxygen levels:

  • Mild: PaO2/FiO2 ratio of 200-300, PEEP 5 or more
  • Moderate: PaO2/FiO2 ratio of 100-200, PEEP of 5 or more
  • Severe: PaO2/FiO2 ratio < 100, PEEP of 5 or more
• ABG findings in ARDS:

  • Low PaO2 despite supplemental O2 leads to refractory hypoxemia
  • PaCO2 initially low from hyperventilation (alkalosis) but eventually increases as the patient fatigues (hypoventilation/acidosis)
• ALF nur interventions - secretion control

  • hydration
  • humidify oxygen
  • cough and suction
  • incentive spirometry
• ARDS:

  • Direct injury: aspiration, near-drowning, pulmonary contusion, pneumonia, covid
  • indirect injury: sepsis, shock, embolism, pancreatitis, non-thoracic trauma
• ARDS exudative phase patho:

  • within 72 hours, injury to pulmonary capillaries --> increases capillary permeability --> fluid leaking that lymph system cant drain --> fluid accumulation in alveoli --> alveolar edema
  • CM: hypoxemia, increased WOB, decreased lung compliance, decreased CO, normal chest x-ray