Respiratory

Respiratory Lecture: Key Terminology

• Tidal Volume ($V_T$): The amount of air moved in or out of the lungs with each breath.

• Set Respiratory Rate: The number of breaths the ventilator is programmed to deliver per minute.

• Ventilation Modes:

  • Pressure Control Ventilation (PCV)

  • Volume Control Ventilation (VCV)

• Pressure Support (PSV): Additional pressure provided to assist spontaneous breaths.

• PEEP (Positive End-Expiratory Pressure): Positive pressure maintained in the lungs at the end of expiration to keep alveoli open.

• End-Tidal $CO<em>2$ ($ETCO</em>2$): Checks the efficiency of diffusion by measuring $CO_2$ coming out of the patient.

• PIP (Peak Inspiratory Pressure): The maximum pressure reached during inspiration.

  • High PIP is undesirable and indicates an obstructive problem.

  • A high pressure alarm will sound if PIP is too high.

• PPlat (Plateau Pressure): Measures how compliant or elastic the lungs are (their ability to open and close).

  • Low PPlat is associated with conditions like ARDS (Acute Respiratory Distress Syndrome).

• $V_e$ (Volume every minute or Minute Volume): The total volume of air exhaled per minute.

• VAP (Ventilator-Associated Pneumonia): A common complication of mechanical ventilation.

• $SaO<em>2$ and $SvO</em>2$:

  • $SaO_2$: Arterial oxygen saturation.

  • $SvO_2$: Mixed venous oxygen saturation (representing oxygen saturation in the veins).

Artificial Airways

• Purposes:

  • Establish an airway.

  • Protect the airway.

  • Facilitate airway clearance.

  • Facilitate mechanical ventilation.

• Types of Airways:

  • Oropharyngeal Airway (OPA)

  • Nasopharyngeal Airway (NPA)

  • Endotracheal Tube (ETT)

  • Tracheostomy

Oropharyngeal Airway (OPA)

• Placement:

  • Insert with the "C" curve facing up (towards the hard palate).

  • Once it reaches the back of the throat, rotate $180^ ext{o}$ so the "C" curve faces down, resting over the tongue.

  • Measure the correct size from the corner of the mouth to the angle of the jaw or earlobe.

• Function:

  • Prevents the tongue from falling back and obstructing the airway.

  • Allows for suctioning.

• Important Contraindication: NEVER place in a conscious, alert, or semi-conscious patient with an intact gag reflex due to the high risk of gagging, vomiting, and aspiration.

• Description: A hard plastic device inserted through the mouth, extending to the pharynx.

• Nursing Care:

  • Monitor airway patency.

  • Listen to breath sounds.

  • Suction as needed.

Nasopharyngeal Airway (NPA) “Trumpet”

• Description: A flexible tube inserted nasally, extending to the base of the tongue.

• Function:

  • Allows for suctioning through its internal opening, maintaining airway patency.

  • Can be used in conscious patients.

  • Useful when frequent nasotracheal suctioning is required.

• Nursing Care:

  • Ensure the patient has no bleeding issues: Assess for risk of epistaxis (nosebleed) or coagulopathy (e.g., patient on Coumadin, blood thinners, or with bleeding disorders).

  • High PT/PTT or clotting time increases bleeding risk; use with caution if no other choice.

  • Do NOT connect to a ventilator; it is only for airway management.

Endotracheal Tube (ETT)

• Description: A semi-rigid tube inserted nasally or orally, extending into the trachea.

• Purpose:

  • Provides airway protection.

  • Used with direct mechanical ventilation; ONLY an ETT or tracheostomy can be connected to a ventilator.

• Cuff:

  • Located at the distal end of the tube.

  • Purpose: Protects the lower airway from upper airway secretions (reduces aspiration risk).

  • Note: The cuff does NOT hold the tube in place.

• Placement:

  • Inserted by personnel with advanced training.

  • Placed through the mouth (oral, more common) or nose (nasal).

  • Securing the ETT:

    • Tied around the patient’s mouth or secured using specialized ETT holders/tapes.

    • Size: Refers to the diameter of the tube (a bigger number indicates a bigger size).

    • Lip Line: Indicates how deep the tube is inserted. The lip line number must be documented every shift to monitor for migration.

• Confirming Placement:

  • Capnography ($CO<em>2$ detector): The most immediate and reliable indicator of placement. A change in the $O</em>2$ detector from purple to yellow indicates the presence of $CO_2$, confirming tracheal placement.

  • Chest X-ray: The definitive confirmation of ETT placement. The tube should be $3-4 ext{ cm}$ above the carina (the bifurcation of the bronchi).

  • Auscultation: Listen for bilateral breath sounds.

  • Bilateral Chest Rise: Observe symmetrical chest movement.

  • End-tidal $CO<em>2$ device: Confirms exhaled $CO</em>2$.

  • Lip line number: Note the number at the patient's lip line to monitor for tube migration; this number should remain constant during shift changes.

• Inline Suctioning:

  • Allows suctioning without disconnecting the patient from the ventilator circuit.

  • Advance the catheter, press the suction button, and withdraw.

• Intubation Medications: Given before ETT placement to facilitate the procedure and minimize patient discomfort.

  • Paralytics: Succinylcholine (short-acting), Rocuronium (longer-acting) – used to prevent involuntary muscle twitches/tremors.

  • Sedatives: Etomidate, Ketamine – used to calm the patient.

  • Note: If a patient is pulseless and apneic, do NOT administer sedatives as they are already unconscious and do not require sedation.

• Nursing Care:

  • Confirm equipment and suction are working properly.

  • Preoxygenate the patient for intubation.

  • Administer medications for intubation.

  • Provide good oral hygiene.

  • Reposition the tube from side to side.

  • Suction when needed.

  • Note markings on the tube to ensure proper position is maintained.

• Complications:

  • Trauma from insertion.

  • Infection/Ventilator-Associated Pneumonia (VAP).

    • Prevention: Oral hygiene, hand hygiene, suctioning PRN, HOB elevated $30^ ext{o}$. If an NG tube is present, check gastric residuals Q4H (high residuals, e.g., >$2 imes$ feeding rate, increase aspiration risk), repositioning the patient side-to-side.

  • Mucosal swelling.

  • Tracheoesophageal fistula (rare, but severe).

Tracheostomy

• Description: A surgical opening in the trachea, typically used for patients requiring extended mechanical ventilation (e.g., >$3-7$ days).

• Advantages (over ETT for long-term airway management):

  • Less traumatic.

  • Oral feeding is possible.

  • Improves patient comfort.

  • Improved ability to communicate.

  • Facilitates weaning.

• Placement: Inserted directly into the trachea through a stoma in the neck.

• Components:

  • Inner cannula: Can be disposable or reusable (removed, cleaned, reinserted).

  • Ties: Secure the tracheostomy tube in place around the neck.

  • Obturator: A smooth, curved guide inserted into the outer cannula during insertion/reinsertion.

    • Purpose: Smoothens the end of the tracheostomy tube, making reinsertion easier and preventing trauma.

    • Crucial: Always keep an obturator and a new tracheostomy tube (same size or smaller) at the patient’s bedside.

• Nursing Care:

  • Clean site every $8$ to $12$ hours.

  • Replace inner cannula daily following facility policy.

  • Change tracheal ties as needed.

  • Suction PRN.

• Accidental Decannulation:

  • First $7$ days: May require reintubation before an emergency tracheostomy can be done. If reinsertion is difficult, cover the stoma with sterile gauze and ventilate the patient with a bag-mask device over the mouth and nose. Call for immediate assistance (physician, RT).

  • After approx. $7$ days: The tract is formed, and the trach can be reinserted into the stoma using the obturator.

Suctioning

• Types:

  • Oral suctioning: Removal of posterior oropharyngeal secretions.

  • Nasotracheal suctioning: A sterile procedure using a flexible red rubber catheter passed through the nostril to the nasopharynx.

  • Endotracheal and Tracheostomy suctioning: Performed using inline suction catheters.

• Note: Instillation of normal saline to facilitate removal of thick secretions is NOT recommended.

• Indications for Suctioning:

  • Visualization of secretions in the airway.

  • Auscultation of crackles, rhonchi, or indication of mucus plugs, or productive coughing.

  • Increase in peak airway pressure.

  • Decrease in tidal volume.

  • Hypoxia.

Ventilation

Manual Ventilation

• Device: Ambu Bag, bag-valve-mask (BVM) device.

  • Always connect to $100\%$ oxygen.

  • The force of the squeeze determines the tidal volume.

  • The number of squeezes per minute determines the respiratory rate.

  • Force and rate together influence the peak flow.

• Procedure:

  • Ensure a proper seal and gentle squeezing.

  • Watch for bilateral chest rise.

  • Allow for complete exhalation between breaths.

  • Monitor for abdominal distention.

• Risks:

  • Pneumothorax: Caused by bagging with too much air or excessive pressure.

  • Abdominal Distention: Air entering the stomach instead of the lungs.

Mechanical Ventilation

• Indications for Respiratory Failure:

  • pH < $7.25$

  • $PaCO_2$ > $50 ext{ mmHg}$

  • $PaO_2$ < $50 ext{ mmHg}$

• Goals:

  • Maintain alveolar ventilation.

  • Correct hypoxemia.

  • Correct respiratory acidosis.

  • Rest ventilatory muscles.

  • Maximize oxygen transport.

• Mechanism: Pushes air (oxygenated) into the patient's lungs, relying on the patient's lungs to expel air.

ECMO (Extracorporeal Membrane Oxygenation)

• Description: Oxygenates the patient's blood outside the body (similar to dialysis for oxygen), then returns it.

• Use: Employed for severe lung/heart failure.

Laryngeal Mask Airway (LMA)

• Description: A supraglottic airway device that sits over the larynx.

• Placement: Can be placed blindly.

• Function: Covers both the trachea and esophagus to provide a seal for ventilation.

Modes of Positive-Pressure Ventilation

• Volume Ventilation: A preset volume of air is delivered with each breath.

• Pressure Ventilation: A preset driving pressure is delivered and sustained throughout the inspiratory phase of ventilation.

• High-Frequency Ventilation: Delivers a small volume of air at a very fast rate (mimicking panting).

Lung Injury Risk with Positive-Pressure Ventilation

• Barotrauma: Lung injury due to excessive pressure, which can lead to pneumothorax.

• Volutrauma: Lung injury due to excessive tidal volume.

• Atelectrauma: Lung injury resulting from the repeated opening and closing of alveoli.

• Biotrauma: Lung injury caused by inflammatory mediators (e.g., in sepsis).

• VILI (Ventilator-Induced Lung Injury) / VALI (Ventilator-Associated Lung Injury): General terms for lung damage related to mechanical ventilation.

Ventilator Settings

• $FiO_2$ (Fraction of Inspired Oxygen):

  • The percentage of oxygen delivered in the inspired air.

  • Range: Room air is $21\%$; ventilators can deliver up to $100\%$.

• Tidal Volume ($V_T$):

  • The amount of air delivered with each breath.

  • Recommended: $5-8 ext{ mL/kg}$ of body weight.

• Respiratory Rate:

  • Set Rate: The number of breaths the ventilator is programmed to deliver per minute.

  • Total Rate: The patient's observed respiratory rate (includes machine-delivered breaths + spontaneous breaths).

  • Spontaneous Rate: The number of breaths the patient initiates on their own ($ext{Total Rate - Set Rate}$).

  • Always assess the patient's actual breathing effort in addition to the ventilator settings.

• Positive End-Expiratory Pressure (PEEP):

  • Positive pressure maintained in the lungs at the end of expiration.

  • Purpose: To keep alveoli open (prevent alveolar collapse) and promote the diffusion of oxygen and $CO_2$.

  • Caution: High PEEP can decrease BP due to increased intrathoracic pressure, which reduces venous return to the right atrium, leading to lower CVP and decreased cardiac output ($CO$).

• Peak Flow: The velocity of gas flow per unit of time, expressed as liters per minute.

• Inspiratory Pressure Limit (High Pressure Alarm):

  • The highest pressure allowed in the ventilator circuit.

  • Causes of high inspiratory pressures include coughing, secretions, or kinked tubing.

• Sensitivity: Controls the amount of patient effort required to initiate a breath.

• Inspiratory:Expiratory (I:E) Ratio:

  • Normal is $1:2$ or $1:3$. This ratio allows adequate time for air to passively exit the lungs.

  • An inverse I:E ratio improves oxygenation by allowing longer inspiratory times and more opportunity for gas exchange.

Ventilator Alarms

• High Pressure Alarm (Indicates obstruction to airflow):

  • Causes: Kinked ETT, patient biting on the tube, secretions/mucus plug, coughing, gagging, or fighting the ventilator, pneumothorax, bronchospasm, decreased lung compliance (e.g., ARDS, pulmonary edema).

• Low Pressure Alarm (Indicates leak in the system):

  • Causes: Disconnection of tubing (ETT or ventilator tubing), a hole in the tubing, ETT cuff leak, or accidental extubation.

Ventilator Volume Modes

• Assist-Control (A/C) Mode:

  • Provides full ventilatory support.

  • Respiratory rate and tidal volume are preset.

  • A preset tidal volume is delivered with each breath, including both preset and spontaneous breaths.

  • If the patient initiates a spontaneous breath, the ventilator "assists" by delivering the full preset tidal volume (or pressure) for that breath as well.

  • Use: Ideal for patients who are sedated, paralyzed, or have minimal to no spontaneous breathing effort and are fully dependent on the ventilator.

  • Pressure Support: Not typically used as a separate setting in AC mode, as every breath already receives full ventilatory support.

  • Problem: If a patient on AC mode starts taking many spontaneous breaths (e.g., a total rate of $40$ with a set rate of $12$), they can become hyperventilated and develop respiratory alkalosis.

  • Troubleshooting: Sedate the patient to reduce spontaneous breaths, or decrease the set tidal volume.

• Synchronized Intermittent Mandatory Ventilation (SIMV) Mode:

  • Respiratory rate and tidal volume are preset for mandatory breaths.

  • Breaths initiated above the preset rate are at the patient’s own spontaneous tidal volume.

  • Use: Commonly employed for weaning patients off the ventilator.

Ventilator Pressure Modes

• General Characteristics of Pressure Modes:

  • A maximum peak inspiratory pressure is preset.

  • The ventilator delivers a breath until the pressure limit is reached and then stops.

  • Respiratory rate, inspiratory pressure limit, and I:E ratio are preset (NOT tidal volume).

  • Tidal volume varies with each breath, depending on lung compliance.

• Volume Control (VC):

  • The ventilator delivers a preset tidal volume ($V_T$) with each breath.

  • Settings: Tidal volume and respiratory rate are set.

  • Pressure: Inspiratory pressure varies based on lung compliance and airway resistance.

  • Analogy: Think of filling a bucket with a set amount of water.

• Pressure-Controlled Ventilation (PCV):

  • The ventilator delivers a preset inspiratory pressure with each breath.

  • Settings: Inspiratory pressure and respiratory rate are set.

  • Volume: Tidal volume varies based on lung compliance.

  • Analogy: Think of filling a bucket to a certain level, regardless of the volume of water needed.

  • Key Principle: You cannot set both volume and pressure simultaneously; you must choose one as the primary control.

• Pressure Support Ventilation (PSV):

  • Assists spontaneous breaths with a preset inspiratory pressure level.

• Inverse Ratio Ventilation (IRV):

  • Inspiratory time is greater than or equal to expiratory time.

• Airway Pressure Release Ventilation (APRV):

  • High and low pressures are timed during the inspiration phase.

• Volume-Guaranteed Pressure Options (VGPO):

  • Delivers a preset tidal volume by utilizing a pressure control mode.

• Continuous Positive Airway Pressure (CPAP):

  • Description: The patient breathes entirely spontaneously (on their own).

  • Mechanism: Provides a continuous level of positive pressure throughout the breathing cycle.

  • Settings: No set tidal volume or respiratory rate. The patient determines their own rate and volume.

  • Function: Keeps alveoli open and improves oxygenation.

  • Use: Commonly used as a weaning mode and for treating sleep apnea.

  • Pressure Support: CPAP is a form of pressure support ventilation as it provides continuous positive pressure.

• Noninvasive Bi-Level Positive-Pressure (BiPAP):

  • Delivered through a face mask, nasal prongs, or nasal mask.

  • Provides both an inspiratory pressure and an expiratory (PEEP) pressure.

Ventilator Mode Comparison

Ventilator Nursing Care

• Maintain airway patency.

• Monitor vital signs, arterial oxygenation saturation ($SaO_2$), mental status, respiratory status, and arterial blood gases (ABGs).

• Monitor ventilator settings and alarms.

• Suction as needed.

• Provide psychosocial support.

• Manage nasogastric or orogastric tubes.

• Check endotracheal tube cuff inflation.

• Elevate the head of the bed to $30^ ext{o}$.

• Provide oral hygiene.

• Ensure nutritional support.

• Provide eye care.

Weaning from Mechanical Ventilation

Successful Weaning Principles

• Utilize a multidisciplinary approach.

• Follow standardized weaning protocols and critical pathways.

• Initiate weaning in the morning.

• Medicate the patient for comfort.

• Raise the head of the bed.

• Provide support and reassurance to the patient.

Methods of Weaning

• T-piece trial (flow-by): The patient breathes through the endotracheal tube without a ventilator.

• SIMV (Synchronized Intermittent Mandatory Ventilation): Gradually decrease the number of delivered breaths.

• CPAP (Continuous Positive Airway Pressure): Decreases the patient’s work of breathing.

• PSV (Pressure Support Ventilation): Progressively decrease the amount of pressure support.

Extubation

• Weaning Process: Patients are typically weaned from AC (Assist-Control) to SIMV (Synchronized Intermittent Mandatory Ventilation), then to CPAP (Continuous Positive Airway Pressure), gradually reducing ventilatory support.

• $FiO<em>2$ Reduction: Gradually decrease the $FiO</em>2$ before extubation. Do NOT extubate a patient on $100\%$ $FiO_2$.

• Post-Extubation Complication: Stridor

  • Definition: A high-pitched, harsh sound indicating narrowing of the upper airway, often due to laryngeal edema.

  • Assessment: Auscultate over the neck/trachea, not the chest.

  • Treatment: Administer racemic epinephrine (a bronchodilator) via nebulizer and corticosteroids (to reduce swelling).

Arterial Blood Gas (ABG) Interpretation

ABG Components and Normal Values

• pH: $7.35 - 7.45$ (Acidic to Alkaline)

• $PaCO_2$: $35 - 45 ext{ mmHg}$ (Respiratory component, acidic)

• $HCO_3$ (Bicarbonate): $22 - 26 ext{ mEq/L}$ (Metabolic component, alkaline)

Steps for ABG Interpretation

1. Step 1: Look at the pH.

   • Determine if it is acidic (<$7.35$), normal ($7.35-7.45$), or alkalotic (>$7.45$).

   • This step identifies the primary acid-base disorder.

2. Step 2: Look at the $PaCO_2$ (Respiratory Component).

   • $CO_2$ is acidic.

   • High $CO_2$ (>$45$) = Respiratory Acidosis.

   • Low $CO_2$ (<$35$) = Respiratory Alkalosis.

3. Step 3: Look at the $HCO_3$ (Metabolic Component).

   • $HCO_3$ is alkaline.

   • High $HCO_3$ (>$26$) = Metabolic Alkalosis.

   • Low $HCO_3$ (<$22$) = Metabolic Acidosis.

4. Step 4: Determine Compensation.

   • Uncompensated: pH is abnormal, and one of the other values ($PaCO<em>2$ or $HCO</em>3$) is normal.

   • Partially Compensated: pH is abnormal, and both $PaCO<em>2$ and $HCO</em>3$ are abnormal and moving in the same direction (e.g., both high or both low) in an attempt to normalize the pH.

   • Fully Compensated: pH is within the normal range ($7.35-7.45$), but both $PaCO<em>2$ and $HCO</em>3$ are abnormal. The body has successfully corrected the pH.

     • To determine if it's compensated respiratory or metabolic, check which side of normal the pH leans (e.g., pH $7.36$ with high $CO<em>2$/$HCO</em>3$ suggests compensated respiratory acidosis).

Clinical Application of ABGs

• Respiratory Acidosis (High $CO<em>2$) on a Ventilator: Increase the ventilator's respiratory rate to "blow off" more $CO</em>2$.

• Metabolic Acidosis: May require bicarbonate administration (a temporary fix; the underlying cause must be addressed).

• ABGs are a definitive test for acid-base balance, but clinical assessment is crucial for immediate action.

$PaO_2$ Values (Hypoxemia)

• $PaO_2$ of $60-79 ext{ mmHg}$: Mild hypoxemia.

• $PaO_2$ of $40-79 ext{ mmHg}$: Moderate hypoxemia. (Note: The range overlaps with mild, typically $40-59$ is moderate).

• $PaO_2$ of less than $40 ext{ mmHg}$: Severe hypoxemia.
  (Values may differ slightly in some books)

Priority Interventions for Acid-Base Imbalance (Key Questions)

• $CO<em>2$ vs $HCO</em>3$? (Identifying the primary component)

• Are there airway issues?

• Is this a kidney issue?

• Is the condition acute or chronic?

• What is the immediate fix versus the eventual cause treatment?

• What are the associated disorders?

Unexpected Decompensation (DOPE Mnemonic)

• To evaluate unexpected patient decompensation:

  • D – Displaced ETT (Endotracheal Tube).

  • O – Obstruction (e.g., secretions, kinked tube, patient biting).

  • P – Pneumothorax.

  • E – Equipment failure.

Lung Trauma from Ventilation

• Barotrauma: Lung injury due to excessive pressure. Can lead to pneumothorax.

• Volutrauma: Lung injury due to excessive tidal volume.

• Atelectrauma: Lung injury from repeated opening and closing of alveoli.

• Biotrauma: Lung injury caused by inflammatory mediators (e.g., in sepsis).

• VILI (Ventilator-Induced Lung Injury) / VALI (Ventilator-Associated Lung Injury): General terms for lung damage related to mechanical ventilation.

Treatment for Hyperkalemia (C BIG KD Mnemonic)

• C - Calcium (Calcium Gluconate/Chloride):

  • Function: Protects cardiac muscle from high potassium (K) levels by stabilizing the cardiac cell membrane to prevent life-threatening arrhythmias.

  • Note: Calcium does NOT lower K levels; it buys time for other treatments.

• B - Bicarb (Sodium Bicarbonate):

  • Function: Decreases acidosis associated with high K. Potassium and acid are linked; more alkalotic states tend to cause hypokalemia as K shifts into cells.

• I - Insulin (Fast-acting regular insulin):

  • Function: Drives K into cells, quickly reducing serum K levels.

• G - Glucose:

  • Function: Administered with insulin to prevent the patient from developing hypoglycemia. Glucose also goes into cells, taking potassium with it.

• K - Kayexalate (Sodium polystyrene sulfonate):

  • Function: A group of medications used to treat high blood potassium by binding K in the gastrointestinal tract for excretion.

• D - Diuretics:

  • Function: Promotes urination, increasing renal excretion of potassium.

Ethical and Legal Considerations in Respiratory Care

• Patient Discomfort: Being intubated and restrained can be highly distressing for the patient.

• Communication: Intubated patients cannot speak. Nurses must anticipate needs and advocate for appropriate sedation if agitation is due to discomfort rather than a medical issue.

• Restraints: Often necessary to prevent accidental extubation but must be managed carefully, ethically, and according to policy.

• Advocacy: Nurses must advocate for appropriate sedation and effective communication with both patients and their families.

• Interprofessional Team: In emergent conditions, a multidisciplinary team is crucial, including Intensivist, MD, Palliative care RN, Social worker, RN, Chaplain, Family, Organ donation coordinator, and Case Management RN.

• Important Considerations: Cultural, spiritual, developmental, ethical, and legal factors significantly affect the plan of care for adult patients with complex alterations.

• Geriatric/Bariatric Considerations: Healthcare providers must be respectful, human, kind, empathetic, and non-judgmental. They must also be aware of legal ramifications and follow all national and hospital protocols and policies.

• Developmental Factors: Factors such as genetics, gender, hormones, diet, environment, family history, and ethnicity influence a person's growth, development, and disease process.

Intubation Drugs

• Note: Pulseless and apneic or severely obtunded patients can (and should) be intubated without pharmacologic assistance as they are already unconscious. Other patients require sedating and paralytic drugs to minimize discomfort and facilitate intubation (termed rapid sequence intubation).

• Sedatives/Hypnotics (Usually Given First):

  1. Etomidate: A nonbarbiturate hypnotic; typically given first for sedation.

  2. Fentanyl: An opioid with sedative properties that causes no cardiovascular depression. Higher doses may lead to chest wall rigidity.

  3. Ketamine: An anesthetic with cardio-stimulatory properties. May cause hallucinations or bizarre behavior upon awakening.

  4. Propofol: A sedative and amnesic commonly used, but it can cause cardiovascular depression leading to hypotension.

  5. Thiopental and Methohexital: Effective but can cause hypotension; used less often.

• Neuromuscular Blockers (Paralytics):

  6. Succinylcholine: A depolarizing neuromuscular blocker.

     • Has the most rapid onset ($30 ext{ sec}$ to $1 ext{ min}$) and shortest duration ($3$ to $5 ext{ min}$).

     • Should be avoided in patients with burns, muscle crush injuries > $1$ to $2$ days old, spinal cord injury, neuromuscular disease, renal failure, or possibly penetrating eye injury.

     • Approximately $1/15,000$ children (and fewer adults) have a genetic susceptibility to malignant hyperthermia due to succinylcholine. Monitor potassium (K) levels.

     • In children, succinylcholine should always be given with atropine because pronounced bradycardia may occur.

     • Fasciculations: Involuntary muscle twitches that can sometimes be seen by medical staff after giving succinylcholine (patients may feel them but are too weak to move extremities). Rocuronium is sometimes given with succinylcholine (e.g., to reduce fasciculations).

  7. Alternative Nondepolarizing Neuromuscular Blockers: Have a longer duration of action (> $30 ext{ min}$) but also have a slower onset unless used in high doses that significantly prolong paralysis.

     • Drugs include atracurium, mivacurium, rocuronium, and vecuronium (typically injected over $60 ext{ sec}$).

• Topical Anesthesia for Intubation (Moll, $2018$).
  (Please refer to a drug book for more details, updates, and accuracy on these drugs.)

Management of Pneumothorax/Hemothorax

• General Treatment: Chest tubes and drain systems.

• Chest Tube Drain (Referencing Getinge Education):

  • Excessive bubbling may indicate a leak or air coming out continuously.

  • If a chest tube comes out accidentally, DO NOT PUT IT BACK IN! Reinsertion must be guided, not blindly, to prevent complications like pleural effusion.

  • If the tube comes out, immediately cover the site with Vaseline gauze to prevent air from entering the pleural space.

• Tru Close Drain (Video Reference):

  • A chamber with a one-way valve inserted into the intercostal space (ICS).

  • Used for minor pneumothoraxes; it's a small device that patients can potentially go home with.

• Chest Tube (CT) Removal: Involves applying Vaseline gauze after removal.

Flail Chest

• Definition:

  • Results from mass trauma to the chest, potentially causing ribs to puncture the lung.

  • Can be caused by trauma, falls, or bone diseases.

  • Characterized by two or more contiguous rib fractures with two or more breaks per rib.

  • May involve internal bleeding and lead to respiratory shutdown.

  • It is a life-threatening and very unstable condition.

• Manifestations:

  • Severe chest pain.

  • Shortness of breath (SOB).

  • Paradoxical Breathing: A hallmark sign of respiratory distress where, instead of the chest wall moving out when taking a breath, the chest wall or abdominal wall moves inward.

• Management:

  • Manage deoxygenation, often requiring mechanical ventilation.

  • Blood pressure (BP) and pain management are critical.

  • Stabilize the patient before sending to surgery (OR).

  • Interventions include a chest brace, immobilization, intubation, ventilator support, and chest tube insertion.

  • Surgery may be required to stabilize the fractures.

Management of Pulmonary Embolism (PE)

• Types of PE:

  • Thrombus: Arising from Deep Vein Thrombosis (DVT).

  • Fat Embolism: Mobilized from bone marrow after a fracture or from trauma.

  • Amniotic Fluid Embolism: Enters the maternal circulation after rupture of membranes at the time of delivery.

• Diagnosis: Chest X-ray (CXR), D-dimer test, CT scan (CT angiogram is definitive).

• Prevention:

  • Anticoagulant therapy.

  • Heparin: Administered as a bolus followed by a continuous drip (monitor PTT). Antidote: Protamine sulfate.

  • Coumadin (Warfarin): Used for long-term prevention (monitor PT). Antidote: Vitamin K.

  • PT (Prothrombin Time): Evaluates the presence of factors VII, V, and X, prothrombin, and fibrinogen (extrinsic pathway).

  • PTT (Partial Thromboplastin Time): Measures the integrity of the intrinsic system (Factors XII, XI, VIII, IX) and common clotting pathways. aPTT is activated PTT.

• Treatment of PE:

  1. TPA (Alteplase/Activase): $100 ext{ mg}$ over $2$ hours, or $50 ext{ mg}$ over $2$ hours (weight-based dose).

     • Check for absolute versus relative contraindications.

     • Assess if the patient has a massive PE (characterized by low BP, bradycardia, or cardiac arrest) or a submassive PE.

  2. Streptokinase: Administer $250,000 ext{ U}$ as a loading dose over $30 ext{ minutes}$, followed by $100,000 ext{ U/hr}$ over $12-24$ hours.

  3. TNKase (Tenecteplase): May be considered, although it does not have FDA approval specifically for PE, it is used for stroke and STEMI (ST-elevation myocardial infarction).

Acute Respiratory Failure (ARF) / Severe Acute Respiratory Distress Syndrome (SARS) / ARDS

• General Treatments (Dependent on extent and chronicity):

  • Oxygen therapy.

  • Endotracheal tube (ETT).

  • Tracheostomy.

  • Mechanical ventilation.

  • Noninvasive positive pressure ventilation (NPPV).

• ARDS (Acute Respiratory Distress Syndrome):

  • Characterized by pulmonary edema (non-cardiac in origin) and hypoxemia, frequently involving intrapulmonary shunting and dead lung space.

  • $PaO<em>2/FiO</em>2$ VQ Mismatch: This ratio is crucial in diagnosing ARDS (<$200$).

    • V (Ventilation) Issue: Where air entry into the lungs is diminished.

    • Q (Perfusion) Issue: Where blood flow drops, meaning blood volume cannot reach the alveoli (e.g., due to insufficient BP to perfuse alveoli).

    • Diffusion Issue: Occurs when the exchange of $O_2$ is impacted by issues within the alveoli, such as alveolar flooding.

      • Alveolar flooding results from increased capillary permeability (often due to sepsis, anaphylaxis, etc.) allowing fluids from circulation to enter the alveoli. Normally, only $O<em>2$ and $CO</em>2$ should freely exchange.

      • When alveoli disconnect, they collapse and become further from pulmonary vessels, impeding gas exchange.

    • Dead Lung Space: Refers to areas of the lung with a VQ mismatch, particularly at the bottom of the lung.

  • Diagnostic Criterion: PaO2/FiO2 < 200 in ARDS.

  • Key Characteristics: Hypoxemia and pulmonary edema that cannot be attributed to a cardiac cause.

  • Treatment: Oxygen therapy, ventilation, and PEEP.

    • PEEP Risk: High PEEP can lead to low BP.

    • Hemodynamics: Patients with ARDS are often hemodynamically unstable, frequently experiencing low BP, sepsis, requiring vasopressors, and on a ventilator. Organ systems may be shutting down.

    • VQ Mismatch Treatment: VQ mismatch cannot be treated directly; the underlying causes must be addressed.

  • Intrapulmonary Shunting: Involves deoxygenated blood flowing through both sides of the heart without effective gas exchange.

  • Goal: To maintain adequate tissue oxygenation.

• SARS (Severe Acute Respiratory Syndrome):

  • Treatment involves oxygen, PEEP, mechanical ventilation, and medications for BP support.

  • Respiratory Supportive Care: Directed toward maintenance of adequate gas exchange.

  • Airway Management: Establishment of an airway is critical.

  • Pharmacology: Use of broncho-dilating drugs and antibiotics for respiratory infections.

  • Oxygenation: Ensure adequate oxygenation.

  • Nutrition: Avoid excessive carbohydrates (as this increases $CO_2$ production). Provide $35-45 ext{ Kcal}$ per day to ARDS and SIRS patients, typically via tube feeding or Total Parenteral Nutrition (TPN).

Legal/Ethical Issues and Ventilator Alarms Summary

• Accidental Extubation (Legal/Ethical): If the tube accidentally comes out, immediately place a mask and bag the patient ($ext{Ambu Bag}$).

• Ventilator Alarms:

  • High Pressure Alarm: Interventions include suctioning, checking for kinks in the tubing, assessing for patient coughing or biting the ETT, or "bucking the ventilator." May also indicate pulmonary edema.

  • Low Pressure Alarm: Interventions include checking for leaks in the system, checking for disconnection of tubing from the patient.

  • Apnea Alarm.

  • High Respiratory Rate Alarm.

• Weaning: Focus on lowering ventilator dependency by gradually reducing $O_2$ concentration and decreasing the set respiratory rate.

• Stridor (Post-Extubation): Treatment involves systemic corticosteroids (like dexamethasone) and nebulized racemic epinephrine.