W6 Resp POST PDF

10/11/2023 1 Respiratory illness in the critical care setting 2 Objectives  The student will understand basic principles of ventilator support  The student will be able to interpret Arterial blood gases and the expected response from ventilator support.  The student will understand the physio...

10/11/2023 1 Respiratory illness in the critical care setting 2 Objectives  The student will understand basic principles of ventilator support  The student will be able to interpret Arterial blood gases and the expected response from ventilator support.  The student will understand the physiology and management of respiratory failure, acute lung injury (ALI) and acute respiratory distress syndrome (ARDS).  3 Quick definition of terms  Volume- amount of substance that occupies an enclosed area With gas- we measure this in mL  Pressure- physical force exerted on an object/surface With Gas- we measure this in cmH20,  Compliance- an objects ability to undergo elastic deformation 4 Oxygen Therapy  Principles of oxygen delivery Oxygen is a drug Both detrimental and beneficial effects Ordered in liters per minute (L/min) flow or O2 percentage (FiO2) Primary indication is hypoxemia Goal of therapy: PaO2 greater than 60 mm Hg SaO2 greater than 90%  5 Oxy-Hemoglobin dissociation curve 6 Escalation of Treatment/Decompensation of Patient  Guinevere Tibbals presents to ED with Shortness of breath. HPI: she was diagnosed with pneumonia at an urgent care the day prior.   Supplemental O2 is applied, patient failing to show improvement: Tachypneic, tachycardic, blood pressure dropping, cyanotic  Supplemental O2 is escalated, patient fails to improve   Patient is intubated   Treatment targets respiratory disease   Patient is extubated and sent to progressive unit 7 Oxygen Therapy (continued)  Methods of oxygen delivery Low-flow systems 1 10/11/2023 Low-flow systems ≤8 L/min flow (nasal cannula) Reservoir systems Simple face mask Partial rebreathing mask Non-rebreathing mask High-flow systems – air/o2 blending system Air entrainment mask  BiPap High Flow nasal cannula 8 Simple/Partial/Non-Rebreather 9 High flow nasal cannula 10 Oxygen Therapy (continued)  Complications Oxygen toxicity More than 50% FIO2 for more than 24 hours Carbon dioxide retention Patients with chronic obstructive pulmonary disease at risk Absorption atelectasis Washes out the nitrogen Oxygen replaces nitrogen in the alveoli Alveoli shrink and collapse 11 Oxygen toxicity 12 Artificial Airways –(Avoiding Intubation)  Pharyngeal airways Prevent tongue from obstructing upper airway Oropharyngeal airway Nasopharyngeal airway 13 Artificial Airways (continued) 14 INVASIVE MECHANICAL VENTILATION  Indications Facilitate transport of oxygen and carbon dioxide between atmosphere and alveoli Via Positive pressure ventilation Airway protection  Types of ventilators Positive pressure Negative pressure (“Iron Lung”)  ETT Tubes: Oral ETT Nasal ETT  2 10/11/2023  15 Endotracheal Tubes (continued) 16 Endotracheal Tubes (continued) 17 INTUBATION Procedure Positioning Preoxygenation and ventilation (NRB or Ambubag) • Suction on Standby IV Access to blunt gag reflex/sedate patient Also will need steroids, Abx, IV fluid, pressors, continuous sedation, etc. Limit attempt to 30 seconds Monitoring Auscultation of breath sounds Disposable end-tidal CO2 detector Chest radiograph 18 Intubation 19 Airway Maintenance 20 Airway Maintenance  Humidification  Cuff management Cuff inflation/Cuff Pressure  Suctioning - maintain proper technique Keeping the airway patent Avoiding Complications Technique changes based on: Open (trach) versus closed (ETT/vent) suction systems 21 Suctioning Complications Hypoxemia Bradycardia secondary to vagal nerve stimulation Pain Trauma  22 Airway trauma 23 Indications for Suctioning:  Q8 hours or PRN for episodes of hypoxemia Course crackle over the trachea Elevated peak inspiratory pressure 3 10/11/2023 Decreased tidal volume Visible secretions Suspected aspiration  Assess the strength of cough  24 Contraindications of Suctioning:  Mostly relative: Hypoxia Tissue trauma to tracheal mucosa Severe hypertension Elevated intracranial pressure Pulmonary bleeding Cardiac Dysrhythmias 25 Suctioning: Suction protocols Hyperoxygenation Vents often have ‘suction’ buttons which provide 100% FiO2 for 15-30 seconds Proper cuff inflation Catheter external diameter size No greater than 120 mm Hg suction 26 Suction Catheter VS ETT Size: 27 SUCTIONING:  Instillation of normal saline may contribute to hypoxemia and lower airway colonizationEvidence states to avoid.  28 SUCTIONING:  Only insert to 0.5cm beyond the tip of the ETT Once at the designated depth, apply suction to the catheter Withdraw in a smooth motion while suction is applied Evidence suggests intermittent suction (Lifting up and down on the suction button) may cause tracheal injury Rotating the suction catheter may be done but is not necessary as suction catheters are fenestrated around the circumference of the tube Withdrawal should take no more than 10 seconds Limit to 3 attempts then give the patient a period of rest 29 Sputum Samples: 30 ORAL CARE: 4 10/11/2023  Chlorhexidine or peroxide based cleansers are preferred (Above toothbrush/tooth paste or saline based products)  Should be done every 3 hours and as needed  Oral secretions should be removed with Yankauer suction catheter or suction swab  Significantly reduces VAP (Ventilator associated pneumonia) and subsequent ‘ventilator days’  Other benefits include increased comfort and decreased nausea 31 Where to focus oral care: 32 Endotracheal Tubes (Other complications)  Complications Tube obstruction Tube displacement Sinusitis and nasal injury Tracheoesophageal fistula Mucosal lesions Move tube laterally each day Laryngeal or tracheal stenosis Cricoid abscess 33 34 Tracheostomy Tubes  Indications Preferred for long-term intubation If patient intubated with ETT for more than 7 to 10 days Can be stretched Upper airway obstruction or trauma Neuromuscular diseases 35 Tracheostomy Tubes (continued) 36 37 Communication on a ventilator  Verbal  Nonverbal  Paper or tablet writing boards  Passy-Muir valve 38 Positive Pressure Ventilation 39 40 41 42 Invasive Mechanical Ventilation SETTING**IMPORTANT SLIDE**  Ventilator settings Respiratory rate will see on a vent 5 10/11/2023 Respiratory rate will see on a vent (12-20 (depending on patient condition) Tidal volume (Vt) will see on a vent, use height to get an ideal body weight Dependent on IDEAL BODY WEIGHT Oxygen concentration (FIO2) – 21-100% Peak Pressure- (High P) Ideally limit to 30cmH20, >40cm may be seen with ARDS (Risking barotrauma) Positive end-expiratory pressure (PEEP) Used to improve oxygenation on ventilator To keep alveoli open to decrease shunt Can cause hypotension and pneumothorax 5cmH20= standard vent initiation, maintins normal residual volume Pressure support (PS) Adjusts for resistance of non-flexible tubing 5-20cm H2O 43 iCLICKER  PEEP Can Cause Hypotension when high levels are being used WHY IS THIS??!?!!??!?!? 44 Invasive Mechanical Ventilation MODES**IMPORTANT SLIDE**  Volume Ventilation Modes Assist Control/CMV Synchronized Intermittent Mandatory Ventilation (SIMV)  Pressure Ventilation Modes Pressure Controlled Mode (PCV) Pressure Support Mode (PSV) APRV VGPO 45 Volume Ventilation Modes  Ventilator modes (frequently used clinically) Assist-control (A/C) (also referred to as CMV- Controlled mandatory volume) Synchronized Intermittent mandatory ventilation (SIMV)  46 Assist Control (AC)/CMV  Volume-control mode  Controlled rate is selected If patient breathes faster the ventilator will trigger to deliver full tidal volume (full-volume breath)  Used when patient is first intubated or during anesthesia (ie. During surgery)  Complications: Air trapping, hyperventilation 47 AC waveform 6 10/11/2023 48 Air trapping 49 Assist Control (AC) - EXAMPLE  VENT SETTINGS ON A/C RR = 12 Vt = 500. (based on weight/height) FiO2 = 50% PEEP = 5 Patient will get 500ml 12x/min if they don’t breathe Total minute volume would be: 6000ml/min OR 6L/min If a patient breathes 30x/min, each breath will be supported for a Vt of 500ml Total minute volume would be: 15,000ml/min or 15L/min 50 Synchronized Intermittent Mandatory Ventilation Mode (SIMV)  Rate and tidal volume are preset  If patient wants to breathe above rate, but the tidal volume is varied and dependent on patient’s spontaneous effort.  Adding pressure support during spontaneous breaths can minimize risk of increased work  Has been used as a method of weaning – By decreasing the amount of mandatory breaths 51 Synchronized Intermittent Mandatory Ventilation Mode (SIMV) - EXAMPLE  Settings: RR=14, Vt=400ml, FiO2=50%, PEEP=5 Patient is guaranteed to receive 14 breaths per minute @ 400ml Additional breaths by the patient will not receive support for extra volume beyond the predetermined PEEP Patient take a 100ml breath, vent will NOT push the breath to a full 400ml 52 53 Pressure Ventilation Modes  Pressure-Support Ventilation Mode (PSV)  Pressure-Controlled Ventilation Mode (PCV) Prevents elevated pressure in the lungs (Ideal is below 40 cmH2O)   Airway Pressure release Ventilation Mode (APRV)*  Volume-Guaranteed Pressure Options (VGPO) Mode* 54 Principles of Pressure Modes  Pressure will be set to allow oxygen to be delivered during inspiration.  Lung compliance will influence tidal volume  Weaning occurs by reducing the amount of pressure. 55 Pressure-Support Ventilation Mode (PSV)  Used in conjunction SIMV mode, but here we apply a pressure goal instead of volume   Spontaneous breaths are assisted with pressure to overcome resistance to endotracheal tube during weaning trials 7 10/11/2023 during weaning trials   Often used in weaning, requires intact respiratory center  56 Pressure-Controlled Ventilation Mode (PCV)  Used to control plateau pressures in patients at risk for barotrauma, such as with ARDS or Pulmonary Fibrosis   Pressure is the goal (As opposed to volume as with AC/SIMV) IE If pressure goal is 25cm H20 RR VT- ???  Extends inspiratory time to match expiratory time in order to maintain alveolar expansion Normal inspiratory:expiratory ratio is 1:2 or 1:3 PCV can expand it from 1:1 to 4:1   VT (Volume) will change with lung compliance 57 58 APRV + VGPO  Airway Pressure release Ventilation Mode (APRV)  Volume-Guaranteed Pressure Options (VGPO) Mode   Used when ARDS is untreatable to more conventional modes 59 APRV 60 Apart from changing the Mode to match the problem…  Remember that other settings can be changed: FiO2 – Gives more O2 PEEP – Keeps alveoli open longer, opens collapsed ones, improves aeration RR – Can be augmented to improve gas exchange Pressure Support – Mostly used in weaning trials to overcome diaphragmatic weakness   Remember that some settings are set by the patients demands: Vt – largely based upon ideal body weight and left alone Peak pressure – set at levels that would prevent trauma RR – Can be augmented to improve gas exchange  61 NONINVASIVE POSITIVE PRESSURE 62 NONINVASIVE Bilevel Positive-Pressure Ventilation Mode (BiPAP)  With airtight mask patient receives two different pressure support levels Inspiratory pressure support (IPAP) ie. 12 cmH20 Expiratory pressure support (EPAP), same as CPAP or PEEP 8 10/11/2023 Ie. 5cmH20.  Used in patients with worsening hypoventilation and hypercapnia to prevent intubation  63 Noninvasive Mechanical Ventilation  Define Noninvasive (not intubated) method to administer positive-pressure ventilation  Advantages Decreased frequency of HAP Increased comfort No sedation required   Disadvantages Significant drying of oral mucosa Requires intact respiratory center Pt. must initiate breath Uncomfortable  64 Noninvasive Mechanical Ventilation (continued)  Contraindications/Disadvantages Hemodynamic instability Dysrhythmias Apnea Uncooperativeness / Intolerance of mask Recent upper airway or esophageal surgery Inability to maintain patent airway, clear secretions, or properly fit mask 65 66 Other Non-Invasive Modes:   CPAP (continuous positive airway pressure) Assist spontaneous breathing to improve oxygenation by increasing end-expiratory pressure One level of pressure support, often used with OSA   AVAPS (Average Volume-assured pressure support) – Novel mode on Bipap machine Targets a volume based on preset parameters 67 Ventilator Alarms  Troubleshooting ventilator alarms: if you can not find the problem, take patient off ventilator and manually bag the patient – iClicker time! Low exhaled volume Low inspiratory pressure Low exhaled minute volume Low PEEP/CPAP pressure High respiratory rate 9 10/11/2023 High pressure limit Low pressure oxygen inlet I:E ratio and temperature 68 Care of the Intubated Patient  Nursing management Pulmonary assessment ANTERIOR AND POSTERIOR Arterial blood gas assessment  Oral Care Position changes  Manual rebreather mask at bedside for emergencies Monitor for respiratory muscle fatigue Educate patient (if appropriate, ie. Prior to surgery) and family about function of mechanical ventilation 69 Weaning  1. Intubation  2. Positive pressure/ventilator therapy  3. Weaning from ventilator support  4. Extubation 70 Nursing Assessment: Monitor for respiratory muscle fatigue Intercostal retractions Bradypnea Diaphoresis Tachycardia Change in mental status- tripoding/anxious to somnolent Lack of airflow Educate patient (if appropriate, ie. Prior to surgery) and family about function of mechanical ventilation  Bag/Valve mask at the Bedside:  71 72 Readiness Criteria Cause of Respiratory failure has improved  Hemodynamically stable NSR or Tachycardia less than 140, 10 10/11/2023 No shock states requiring vasopressor management No active ischemia or pulmonary edema  73 Readiness Criteria SaO2 >90% on FiO2: 40% or less, PEEP 5 cm  Chest x-ray reviewed for correctable factors and treated  Metabolic indicators (serum pH, major electrolytes) within normal limits   74 Readiness Criteria HCT>25%, Hgb >8 (7 is the newer trend)  Core temp 36-39 degree  Adequate management of pain/anxiety/agitation  No residual neuromuscular blockade  ABG values normalized or at patient’s baseline   75 Contraindications:  Cardiovascular instability  Open abdomen –OR- plans to return to Operating Room within 24 hours  Ongoing therapeutic hypothermia  Glasgow coma scale of less than 8  Any acute brain injury with invasive intracranial pressure monitoring   Patients who aren’t doing well… PaO2/FiO2 ratio less than 150, still requiring high PEEP, High FiO2, Minute Volume >15L per minute, RSBI (Rapid Shallow breathing index) over 105 (tachypnea with low minute volume). (This last bullet is very technical- not necessary to memorize, but should make logical sense)    76 *PaO2/FiO2 Ratio* 11 10/11/2023  PaO2/FiO2 ratioNormal: PaO2 ~100mmHg Normal: FiO2 ~.21 PaO2/FiO2 ration: 100/.21 = 476   Poor ratio example: PaO2 – 75 FiO2 - .50 Ratio – 75/.5 = 150. 77 SBT (Spontaneous Breathing Trials) – Techniques used: T-Tube Trial- Opening the end of the ventilator circuit so patient is doing all the work, still gets humidified O2.  Pressure Support Ventilation- Gives the patients extra pressure to theoretically overcome the resistance of the ETT lumen Automatic Tube Compensation- Modern technique, similar to PSV but the ventilator automates the pressure support.  Continuous Positive Airway Pressure (CPAP Mode)- provides continuous pressure support and may increase the functional residual capacity of the lungs. Potential risk of left ventricular dysfunction upon extubation if using high PEEP.  Automated Weaning- Similar to automated tube compensation- but the vent will increase the PSV if minute volume drops or respirations increase.       78 79 Weaning process: SBT (Spontaneous Breathing Trials) If the patient meets the discussed criteria… Transfer to PSV (Pressure support ventilation) or CPAP mode, etc, adjust support level to maintain patient’s respiratory rate at less than 35 RR Drive pressure should start at 5 – 8 cmH20 Observe for 30 - 120 minutes for signs and symptoms of early failure Tachypnea Low TV for patient size 12 10/11/2023 Low TV for patient size Tachycardia  If patient fails tolerance criteria, increase PSV as needed to achieve ‘rest’ settings. Goal RR <20 –   80 Weaning process: Repeat SBT attempt on PSV 10 cm after rest period. If patient fails second weaning trial, implement strategy for long term ventilation  Long-term ventilator weaning requires repeated trials of PSV.  Provide patient with ‘rest’ settings at night for at least 6 hours at night on full vent support    81 Failure to Wean  Tolerance Criteria: if patient displays any of the following, return to rest settings.  Sustained RR > 35 breaths/per minute  SaO2 <90%  Tidal volume of 5 ml/kg or less  82 Failure to Wean Sustained minute ventilation greater than 200 ml/kg/min  Evidence of respiratory or hemodynamic distress  Labored breathing Increased anxiety diaphoresis or both Sustained HR > 20% higher or lower than baseline Systolic BP exceeding 18- mmHg or less than 90 mm Hg    83 Extubation candidate: Mental status alert and cooperative  Good cough and gag reflex and able to protect airway and clear secretions 13 10/11/2023   NG tube/OGT feedings should be on hold for several hours prior to extubation  For long-term ventilated patient, success is defined as maintaining spontaneous ventilation for 24 hours. 84 EXTUBATION Preparation  Preparation for extubation begins on the day of intubation!   85 Extubation/Decannulation  2 RN’s should be at bedside, along with the intensivist/MD in some cases  Instruct patient about the procedure  Hyperoxygenate with 100% FiO2  Suction trachea (then oral airway)  Deflate cuff  Tell patient to breath around ETT  Remove ETT  Administer oxygen – Nasal Cannula to Non-Rebreather  Monitor vital signs 86 Extubation/Decannulation (continued)  Suction airway as needed   Monitor for respiratory distress   Observe for signs of airway occlusion   Encourage voice rest for 4 to 8 hours   Monitor ability to swallow and talk 87 Keeping the patient off the ventilator:  Ensure oxygenation is adequate Hi Flow O2 BiPap or CPAP  Secretion management via coughing, deep breathing and suctioning  Bronchodilators as needed  Sitting upright and mobilize if no contraindications  88 Post extubation Stridor Occurs in less than 10% of ventilated ICU patients  High pitched upper airway whistling  Occurs more often in older patients (80+), asthmatics, following aspiration and prolonged 14 10/11/2023 intubation (6+ Days)   Tx with steroids IV or nebulized epinephrine   Consider reintubation if airway occlusion is imminent 89 Extubation/Decannulation (continued)  At this time is is appropriate to: Remove Foley catheter Remove wrist restraints Address removal of central line Address removal of arterial monitoring catheters  NGT may or may not stay in – OGT must be removed with ETT 90 Self Extubation  Case by case scenario  Oxygenate the patient with bag valve mask  Assess stability   Young patients who are weaned from sedation typically do better than geriatric counterparts   Assess for tracheal/vocal chord trauma  91 Overcoming barriers to ventilator weaning in the elderly  Sleep deprivation  Imbalance of nutrition less than body requirements and risk for fluid volume imbalance  Acute pain, anxiety and acute confusion  Risk for constipation and diarrhea  Risk for activity intolerance and impaired med mobility or impaired physical mobility 92 Case  Mr. Sanders is an 81-year-old male with a history of COPD. He was admitted 1 week ago for bilateral pneumonia/acute respiratory failure and was intubated in the ER. Following a week of IV antibiotics his chest X-ray shows improvement and his FiO2 requirements are decreasing.   The plan today is to wean the patient from the ventilator.   As the nurse, you start by withholding sedation and describing the weaning process to the patient. When the patient is switched to ’Pressure support mode’ we quickly notice alarms saying ‘Low Minute Volume’. The patient is also becoming tachypneic, tachycardic and diaphoretic. His pulse ox is also dropping below 90%, which is where he was when we started weaning.  What is going on the with patient? 93 BREAK 94 Critical Respiratory Disorders -ACUTE RESPIRATORY FAILURE 15 10/11/2023 -ACUTE RESPIRATORY FAILURE -ACUTE RESPIRATORY DISTRESS SYNDROME 95 Acute Respiratory Failure - ARF  Sudden and life-threatening deterioration in pulmonary gas exchange   Inadequate oxygenation with PaO2 <50mmHg. PaCO2>50 mmHg and pH<7.35 O2 depletion, CO2 retention  Baseline ABGs are assumed normal 96  Etiology Intrinsic Lung/Airway Disease Large Airway Obstruction Bronchial Diseases Parenchymal Diseases Cardiovascular Disease 97 Acute Respiratory Failure (continued) Extrapulmonary Disorders Disease of the Pleura and the Chest Wall Disorders of the Respiratory Muscles and Neuromuscular Junction Disorder of the Peripheral Nerves and Spinal Cord Disorder of the CNS 98  Classified as Acute Hypoxemic Respiratory Failure - Needs O2, presents with: Low PaO2 Low PaCO2   Classified as Acute Hypercapnic Respiratory Failure – Needs to expel CO2, presents with: Marked elevation of carbon dioxide Preserved PaO2 levels   Combined Acute Hypoxemic and Hypercapnic respiratory failure Low PaO2, High PaCO2 99  Need of intubation Dyspnea Depressed mental status or coma Severe respiratory distress Extremely low or agonal respiratory rate Obvious respiratory muscle fatigue Peripheral cyanosis Impending cardiopulmonary arrest 100 16 10/11/2023 Acute Respiratory Failure (continued)  Presentation Dyspnea Cyanosis Restlessness Confusion Anxiety Delirium Tachypnea Tachycardia Hypertension Cardiac dysrhythmias Tremor Somnolence 101  Diagnosis Uses arterial blood gas (ABG) analysis PaO2 less than 60 mm Hg (central cyanosis) PaCO2 greater than 45 mm Hg (headache and dyspnea) Confusion Somnolence  In patients with chronically elevated PaCO2 levels, the pH is considered (pH < 7.35) 102  Medical management Oxygenation Oxygen therapy is given to correct hypoxemia Maintain oxygen saturation at more than 90% Meet needs of tissues Avoid oxygen toxicity 103 Ventilation Noninvasive ventilation Invasive mechanical ventilation Initial ventilator settings individualized for 17 10/11/2023 Initial ventilator settings individualized for Underlying condition, patient size, and severity of respiratory failure Usually started on volume ventilation in the assist-control mode 104  Pharmacology Bronchodilators: open airways (Albuterol) Anticholinergic agents: Ipratropium Bromide Sedatives: comfort, decrease work of breathing Analgesics: pain control Neuromuscular blockade: paralysis Facilitate optimal ventilation Decrease oxygen consumption 105  Medical management Acidosis Respiratory acidosis is often corrected with effective oxygenation and ventilation iCLicker: What vent setting could we augment to improve CO2 exhalation???  Sodium bicarbonate not recommended even with pH less than 7.1 106  Avoid both malnutrition and overfeeding Enteral route is preferred Parenteral route = Infection risk Initiate nutrition before day 3 on ventilator if well nourished and within 24 hours on ventilator if malnourished 107 Complications of ARF Ischemic-anoxic encephalopathy Cardiac dysrhythmias Venous thromboembolism*** Gastrointestinal bleeding*** Artificial airway complications Mechanical ventilation complications Enteral and parenteral nutrition complications Keep feeding running to maintain patency Peripheral arterial cannulation complications 108  Positioning Position patient to best match V/Q. (Ventilation/Perfusion)  Place least affected area of lung in a dependent position 18 10/11/2023 Place least affected area of lung in a dependent position Good lung down, bad lung up promotes drainage  Position at least every 2 hours  Sitting up in chair  early mobilization 109 Promoting secretion clearance Systemic hydration Humidifying supplemental oxygen Suctioning Elevate the head of bed 30 to 45 degrees When extubated: deep breathing and use of incentive spirometer; coughing if secretions are present 110 CASE 2  23 year old female presents to ER with asthma attack that is refractory to ‘home treatment’.  Patients mother states she has been sick for the past couple days and tried 3 ‘neb’ treatments prior to arrival.  Current meds include: one puff twice daily Advair (Fluticasone/salmeterol), 2 puffs as needed beta-agonist (Albuterol) (nebulizer is part of patients action plan).  Patient presents sitting up in stretcher, holding on to the side rails, accessory muscle use present, RR =30, wheezing audible from the doorway.  Neuro: Anxious, but oriented x3  Resp: diminished wheezes  Cardiac: ST on monitor, rate of 140’s 111 112 Acute Respiratory Distress Syndrome - ARDS  Description Pulmonary injury due to secondary effects--> ie. Septic Shock Pulmonary manifestation of multiple organ dysfunction syndrome-result of release of cellular and biochemical mediators  Characterized by **Diffuse pulmonary infiltrates on chest x-ray and hypoxemia **Lung fibrosis unlike other disease **alterations of lung epithelium and vascular tissue **Increased pulmonary edema and impaired gas exchange. 113 Statistics Related to ARDS  Mortality rate of 40%+  Greatest risk for development: Sepsis 19 10/11/2023 Sepsis Age older than 65 years Severe acute illness Preexisting chronic disorder Definition of ARDS 114   Diagnosis of ARDS requires 4 criteria:  Acute onset Bilateral infiltrates (on CXR) PAOP of <18mmHg  PaO2/FiO2 Ratio of: 200-300 = Mild ARDS 100-200 – Moderate ARDS <100 – Severe ARDS 115 ARDS 116 COVID ARDS 117 ARDS 118 Healthy CXR 119 120 Physiological Effects of ARDS 121  Impaired Ventilation and Oxygenation  Resulting Pulmonary vasoconstriction Pulmonary hypertension Reduced blood flow  Decrease lung compliance and increase airway resistance  Fluid-filled alveoli  Alveolar collapse  Bronchoconstriction Acute Resp Distress 122 1 Direct injury 2 Aspiration Post Drowning Infectious pneumonia Lung contusions with trauma Inhalation injury Neurogenic pulmonary edema 20 10/11/2023 Neurogenic pulmonary edema 3 Indirect injury 4 Sepsis Burns Trauma Blood transfusion Drug or alcohol overdose Acute pancreatitis Multiple fractures Venous air embolism Amniotic fluid embolism  123 ARDS  Exists in 3 stages 124 STAGE 1 – Early Exudative Stage  First 7-10days result in diffuse alveolar damage (DAD)   Mediator-induced disruption of vascular bed  Increased interstitial and alveolar edema Increasingly permeable to proteins (much like vascular bed during septic shock)  Acute inflammation of the lung parenchyma   125 STAGE 2 – Fibroproliferative stage  After the first week  Pulmonary Edema resolves  Cellular changes occur  Collagen and myofibroblasts cells used for healing, resulting in scar tissue  126 STAGE 3 – Fibrotic stage  Fibrosis and Scarring of the lung fields  Decreases in PaO2, Increases in PaCO2  Multiorgan involvement, SIRS  Progressive lung fibrosis Ventilation management difficulties Increased airway pressures Pneumothoraces  127 Physical Examination During ARDS  Hemodynamically unstable  Hypotension, tachycardia  Temp dysregulation  Hyperthermia or hypothermia 21 10/11/2023 Temp dysregulation Hyperthermia or hypothermia  Hypoxemia  Tachypnea, dyspnea   Restlessness and agitation Lethargy ominous sign  Crackles 128 Arterial Gas Analysis  Refractory hypoxemia Low PaO2 despite high FiO2 delivery  Early—decreased PaCO2 Respiratory alkalosis   Hypercapnia develops later. Respiratory acidosis 129 Development of Intrapulmonary Shunt  Perfusion without ventilation (shunt)  Ventilation without perfusion (dead space)   Combination of both in ARS ARDS more than 15% shunt  PaO2: FiO2 ratio Normal > 300 200 associated with 15% to 20% intrapulmonary shunt 100 associated with more than 20% intrapulmonary shunt 130 iCLICKER!!!!!  What is another disease process that manifests as “Shunting” in the lungs? Ie. Perfusion w/o ventilation 131 iCLICKER!!!!!  What is a disease process that manifests as “Dead Space” in the lungs? Ie. Ventilation without perfusion 132 VALI  Ventilator Associated Lung Injury  Also referred to as Barotrauma (Injury secondary to pressure)  Occurs due to low compliance of the lungs secondary to fibrosis 133 Ventilation Strategies  Permissive hypercapnia more concerned with oxygenation than CO2 retention  Pressure-controlled ventilation Lower Volume and Less trauma to the lungs, accommodates for reduced compliance  Inverse-ratio ventilation Longer inspiratory phase  Limit plateau pressures,  Increase PEEP 22 10/11/2023 Increase PEEP Keeps alveoli open  Airway pressure release ventilation (APRV) 134 Novel Ventilation Strategies  HFOV (High frequency oscillatory venilation)   Extracorporeal lung-assisted technology* ECMO 135 Positioning  Frequent position changes Continuous lateral rotation  HOB elevated to prevent VAPS  Prone positioning May improve gas exchange 136 Treatment of ARDS  5 P’s of ARDS therapy   Peeing Diuresis to keep lungs less full of fluid  Positioning (Proning) Allow consolidated areas to drain  Protective lung strategies Expanded I:E ratio, PCV  Perfusion Vasopressors for hemodynamic instability  Prednisone (Steroids) Reduce/limit inflammation 137 Pharmacological Therapy  Antibiotics, if indicated Huge risk of Nosocomial infections  Bronchodilators and mucolytics Albuterol, Xopenex  IV corticosteroids Always taper off  Nitric oxide gas via mechanical ventilator  Sedation + Paralytics Facilitates mechanical ventilation, decreases O2 demands 138 Nutritional Support  Enteral feeding benefits  Balanced caloric, protein, carbohydrate, and fat intake Ordered by Registered Dietician  Usually require 35 to 45 kcal/kg/d Most people require half of that to maintain weight 23 10/11/2023 Most people require half of that to maintain weight  Theoretically - High carbohydrates avoided to prevent excess carbon dioxide production 139 Complications of ARDS  Sepsis/SIRS  Barotrauma Pneumothorax Pneumomediastinum  VAP**  Immobility  DVT/PE 140 Mechanical Ventilation  RECAP  Lung protective ventilation strategies Limits ventilator-associated lung injury (VALI)  Includes Low tidal volumes PEEP (Typically higher than 5) Limit plateau pressures to 30 cm H2O PCV Extended I:E ratioes 141 Acute Lung Injury/ARDS (recap continued) Oxygen therapy Lowest level possible to maintain saturation greater than 90% FIO2 preferably less than 50% Positive end-expiratory pressure (PEEP) Purpose is to open alveoli and decrease FIO2 levels Generally PEEP = 10 to 15 cm H2O If PEEP is too high, it overdistends alveoli If PEEP is too low, alveoli collapse during expiration 142 PRONING  Description Match ventilation and perfusion through redistribution of oxygen and blood flow Typically 12 hours on, 12 off  Prone positioning Acute respiratory distress syndrome P/F ratio <150 Criteria Hemodynamic stability (?) Absence of abdominal surgery or spinal cord injury PROBLEMS: Pressure injuries, Airway occlusion, tube and line dislodgement Limitations 24 10/11/2023 Limitations Mechanics of turning  143 PRONING 144 PRONING  Prone positioning Nursing management Eye care/Oral care prior to prone Tubes and drains secure Intubation cart on standby Foley secured at foot of bed May need additional sedation Patient and family education 145 Positioning Therapy (continued) 146 “ROTO PRONE BED” 147 ABG Interpretation 148 -Hypoxemia HypoxemiaPaO2 of less than 80mmHg. •  Can Improve PaO2 with: MoreFiO2 Use as little as possible Higher PEEP Risk of low BP and Barotrauma Longer I:E times Difficult for patients to tolerate Higher Volume/pressure (To a point) Increases Barotrauma risk  149 Arterial Blood Gases and Acid-Base Balance  Lungs are pivotal in acid-base balance  Hydrogen ions (H+) are formed from acids  pH is measure of the body’s hydrogen ion concentration and is inversely related Increase in hydrogen leads to decrease in pH Decrease in hydrogen leads to increase in pH  Normal arterial pH is 7.35 to 7.45  Small changes in pH lead to big physiological changes and even death   CO2 + H20 = H2CO3 = HCO3- + H+ • 25 10/11/2023 • 150 Normal Arterial Blood Gas Values (Vary by Age)   pH: 7.35 to 7.45 “Normal” decrease with age (7.26-7.43 for those >90)  PaCO2: 35 to 45 mm Hg  PaO2: 80 to 100 mm Hg Most oxygen is carried on the Hgb molecule as oxyhemoglobin so PaO2 is only one indicator of effective respirations  HCO3: 22-26mmHg  151 Balancing act… 1   Sources of Acids Glucose metabolism Fat and protein metabolism Anaerobic metabolism Cell destruction 2   Sources of Bases (HCO3) Breakdown of carbonic acid Absorption of bicarb by intestines and reabsorption by kidneys Intra cellular movement Pancreatic production of bicarb  152 How to keep that balance  Buffers   Respiratory Mechanisms: Sensitive to CO2 levels Hyperventilation: “Blow it off” to bring pH up Hypoventilation: Retain CO2 to bring pH down  Rapid response  Renal Mechanisms Slower to take effect Absorption or excretion of HCO3 Formation of acids Formation of ammonium loss of hydrogen and drop in pH  153 Acidosis v. Alkalosis 26 10/11/2023 1 Acidosis  Types Metabolic Respiratory Combined  Manifestations CNS depression Decrease in muscle tone Increased respiratory rate/depth Myocardial irritability   2 Alkalosis  Types Metabolic Respiratory Combined  Manifestations CNS excitement/seizures Tetany, cramps, twitches but weakness Myocardial irritability 154 How To Evaluate ABG’s 1. Evaluate the pH 2. 155 How To Evaluate ABG’s 1. Evaluate the pH 2. 2. Evaluate the PaCO2 (respiratory) and HCO3 (metabolic) Remember that the system will not overcompensate so the pH will represent the primary cause of the imbalance Example: pH = 7.21 (acidosis) PaCO2 = 60mm (higher, increased acid) HCO3 = 26mEqL (normal) What am I ??? 156 How To Evaluate ABG’s 3. Determine degree of compensation For example, if there is a problem with the respiratory system, the renal system will try and move the HCO3 in the opposite direction in an attempt to bring the pH back into the normal range. 27 10/11/2023 the HCO3 in the opposite direction in an attempt to bring the pH back into the normal range. Compensation can be partial or complete Example: pH = 7.3 (acidosis) PaCo2 = 60mm (high, increased acid) HCO3 = 30mEqL (high, increased alkali) What am I? 157 WHAT AM I????? 158 28