Respiratory Care in Immunocompromised Patients

Home Mechanical Ventilation

• Goals: Extend lifespan, enhance quality of life, reduce morbidity, improve physiological function, obtain normal routines, reduce health care costs.

Indications

• Respiratory pump disorders: Neuromuscular diseases, chest wall conditions, spinal cord injuries.
• Airway obstructions: Obstructive diseases, craniofacial abnormalities, hypotonia, obesity, chronic obstructive pulmonary disease (COPD), asthma.
• Lung parenchymal diseases: Interstitial lung disease (ILD), cystic fibrosis.
• Control of respiration disorders: Central hypoventilation syndrome.
• Inability to wean from mechanical ventilation: After and acute illness, after prolonged ventilation for chronic disease, progressive chronic respiratory failure, sleep disturbance (central or obstructive, apnea or hypopnea).

Indications/Symptoms

• Shortness of breath: Especially on exertion or lying down.
• Morning headache and insomnia.
• Fatigue and lethargy.
• Increased respiratory rate.
• Restlessness and anxiety.
• Forced vital capacity < 50% predicted.
• Maximal inspiratory pressure < 60.
• ABG pCO2 > 45.
• Moderate to severe sleep apnea.

Patients

• Cardiopulmonary stability: Positive trend in nutrition/maintenance.
• Stamina for daily activities: Freedom from active/recurrent infection, fever, and deterioration.

Interfaces

• Noninvasive vs. Invasive: Age, cognitive ability, body habitus, ventilatory needs, anticipated length of ventilation, patient/family preference.

Definition of Noninvasive Ventilation (NIV)

• NIV: A ventilatory mode delivering mechanical support without an endotracheal tube/surgical airway. Uses a tight-fitting face or nasal mask.

• Decision to intubate: Made solely on clinical grounds without delay for laboratory evaluation.

• Types: Continuous positive airway pressure (CPAP), Bilevel positive airway pressure (BiPAP).

• CPAP: Does not directly increase tidal volume or minute ventilation.

• BiPAP: Provides supplemental inspiratory tidal volume.

Indications for NIV Use

• Respiratory failure: COPD exacerbation, pulmonary edema, respiratory failure in immunocompromised patients (e.g. AIDS, malignancy), weaning from conventional ventilation, and prevention of reintubation in high-risk patients.
• Specific conditions: Asthma, idiopathic pulmonary fibrosis, obesity hypoventilation, neuromuscular respiratory diseases.
• Do-not-intubate status: In terminal illness or malignancies.

Relative Contraindications

• Cardiac instability: Shock, need for pressor support, ventricular dysrhythmias, complicated acute myocardial infarction.
• Gastrointestinal (GI) bleeding: Intractable emesis and/or uncontrollable bleeding.
• Inability to protect airway: Impaired cough or swallowing, poor clearance of secretions, depressed sensorium and lethargy.
• Status epilepticus.
• Potential for upper airway obstruction: Extensive head/neck tumors, other tumors with extrinsic airway compression, angioedema or anaphylaxis causing airway compromise.

Absolute Contraindications

• Coma.
• Cardiac arrest.
• Respiratory arrest.
• Any condition requiring intubation.
• Non-compliant patient.

Guidelines for Providing NIV

• Duration of treatment starts: With the first 4 hours of treatment.
• Time of minimum treatment: Should receive NIV for as long as possible (a minimum of 6 hours) during the first 24 hours.
• Duration of treatment: Should last until the acute cause is resolved, typically after about 3 days
• Success Criteria: Successful NIV (pH > 7.35, resolution of cause, normal RR) after 24 hours indicates planning for weaning..

Protocol for Initiation of NIV

• Location: Appropriately monitored.
• Patient Position: Bed or chair sitting at > 30-degree angle.
• Mask Type: Full-face mask used for first 24 hours; nasal mask, if preferred.
• Patient Encouragement: Encourage patient to hold the mask.
• Harness and Tension: Apply a harness; avoid excessive strap tension.
• Ventilator Connection: Connect interface to ventilator tubing, turn on ventilator.
• Leak Check and Adjustments: Check for air leaks; readjust straps.

Guidelines for Providing BiPAP

• Initial pressures: IPAP of 10 cm H2O & EPAP of 4-5 cm H2O.
• IPAP increases: Increased by 2-5 cm increments at a rate of approximately 5 cm H2O every 10 minutes, with a usual target of 20 cm H2O.
• Oxygen adjustment: O2 entrained into circuit & flow adjusted to SpO2 >88-92%.

Oxygenation and Humidification

• Oxygen: Titrated to desired oxygen saturation 90-92%.
• Oxygen delivery: Use of oxygen blenders, and adjusting liter flow via oxygen tubing connected directly to the mask or ventilator circuit.
• Heated vaporizer: Use of heated blow over vaporizer if longer application intended.

Bronchodilators

• Administration: Preferably administered outside of the NIV.
• Placement: If necessary, entrain between expiration port and face mask.
• Effect on NIV: Delivery of both oxygen and nebulized solutions is affected by NIV settings.
• Nasogastric tube (NGT): If an NGT is present, a fine bore tube is recommended to avoid mask leakage.

Criteria for Terminating NIV and Switching to Mechanical Ventilation

• Deteriorating pH/PaCO2 levels.
• Tachypnea (>30 bpm).
• Hemodynamic instability.
• Low SpO2 (<90%).
• Decreased level of consciousness.
• Inability to clear secretions.
• Failure to tolerate the interface.

Weaning Strategy

• Day 2: Continue NIV for 16 hours.
• Day 3: Continue NIV for 12 hours, including 6-8 hours overnight use.
• Day 4: Discontinue NIV unless clinically indicated.

Complications of NIV

• Facial and orthodontic changes.
• Aerophagia (PIP > 25 cmH2O).
• Nasal drying/congestion: Humidification.
• Volutrauma (air leak).
• Inadequate ventilation.
• Other issues: • Facial and orthodontic changes, • Aerophagia (PIP > 25 cmH2O), • Nasal drying/congestion (humidify), • Volutrauma (air leak), • Inadequate ventilation, • Gastric distention, • Drying of mucous membranes of nose, nasal congestion, & thick secretions. • Aspiration of gastric contents, • General discomfort, • Claustrophobia,

Ventilator Settings

• Initiation: IPAP/EPAP start with 10/5 cm H2O, with goal to VT 6-7ml/kg.
• IPAP Adjustments: Increased in 2 cm increments up to a maximum of 20-25 cm H2O
• EPAP adjustments: Increase by 2 cm H2O if hypoxia; keep max at 10-15 cm H2O.
• Respiratory rate: Back up respiratory rate increased to 12-16/minute.
• Oxygen adjustment: Adjust FiO2 to achieve SaO2 90-92%.
• Other parameters: Most machines generate a maximum pressure of 20-23 cmH2O; if higher pressures are required, mask leakage will likely be a problem and conventional invasive ventilation will likely need to be prioritized.

FiO2 and Settings

• Initial FiO2: Start with FiO2 a little higher for that prior to NIV
• SaO2 targeting: Aim for SaO2 above 92%.
• Hypoxic patients: In hypoxic patients, increasing the FiO₂ on a BiPAP circuit likely wont improve hypoxia because the decreased FiO₂ is likely caused by increased gas flow through the circuit.

Monitor patient response

• Patient's feelings: The most helpful indicator is how the patient is feeling.
• Compliance: Patient compliance is a key indicator.
• ABGs: Use arterial blood gases (ABGs) to monitor oxygenation and CO₂ clearance.
• Trial of ventilation: A trial (1-2 hours) will typically show a decrease in PaCO₂ (>8 mmHg) increase in pH (>0.06) indicating successful NIV.

Predict failure

• Patient's feelings: Increasing tiredness or deteriorating ABGs despite optimal settings indicates a need for intubation and mechanical ventilation.
• Early intervention: Promptly recognize failure to respond, so that management strategies can be implemented prior to patient collapse.
• Indicators of failure: •Acidosis (pH <7.25) •Hypercapnia (>80 and PH <7.25) •APACHE II score higher than 20. •Neurologic score > 4 •Encephalopathy score >3 •Glasgow Coma Scale score less than 8

BiPAP Limitations

• Augmentation, not primary ventilation: BiPAP only augments respiratory function; not a primary ventilation method.
• Dependent factors: Tidal volume depends upon airway resistance, lung/chest wall compliance, patient synchrony with machine and absence of mask leakage.

Monitoring

• Vitals monitoring: Blood pressure, respiratory rate, heart rate, rhythm, oxygen saturation, level of consciousness.
• Treatment tolerance: Initial monitoring occurs every 15 minutes for 1 hour, every 30 minutes for 2 hours, every hour for 2 hours, and then every 4 hours thereafter..
• Oxygen saturation should be 94-98% (or 88-92% in CO2 retainers)
• Blood gas analysis (ABGs) before commencing treatment, after 1 hour, and within 1 hour of any change in ventilator settings. Further ABGs are performed as clinically indicated.

Advantages of NIV

• Lower intubation rate and mortality: reduced incidence of intubation and mortality in various patients..
• Reduced intensive care unit and hospital stays: reduced time in ICU and hospital.
• Prevention of ventilator-associated complications: Avoid complications of ventilator.

Complications of NIV

• Facial and nasal pressure injury.
• Gastric distension.
• Drying of mucous membranes, nasal congestion, and thick secretions.
• Aspiration of gastric contents.
• General discomfort.
• Claustrophobia.

Literature Review

• 1995 study: BiPAP reduced endotracheal intubation, hospital stay, and mortality in acute COPD patients. Key factors included PaO2 < 45 mmHg, pH< 7.35 and Respiratory Rate>30 bpm.
• 2003 Cochrane review: BiPAP decreased mortality, incidence of ventilator-associated pneumonia, ICU stay, and hospital stay in COPD patients.

Strong/Less Strong Evidence Levels

• Level A: Acute hypercapnic COPD, acute cardiogenic pulmonary edema, patients Immunocompromised.
• Level B: Asthma, Community Acquired Pneumonia, COPD; Weaning in COPD; Avoidance of extubation failure; Post Operative Respiratory Failure; Do not intubate patients.
• Weak/No Benefit: ARDS, Community acquired pneumonia (not COPD), Cystic fibrosis, Weaning (not COPD), OSA/Obstructive Sleep Apnea/Obesity Hypoventilation, Trauma.
• Not indicated: Acute deterioration in ILD, severe ARDS with multi organ failure, post op upper airway or esophageal surgery.

Present Status of NIV

• Increasing use: Application of mechanical ventilator support through a mask is increasingly accepted in emergency departments and ICUs.

Summary of COPD

• Suitable condition: COPD is the optimal condition for NIV
• Effectiveness: Most effective in patients with moderate-to-severe COPD.
• Best responders: Patients with hypercapnic respiratory acidosis (pH 7.20-7.30) are often the best candidates.
• Effectiveness variation dependent on pH: Noninvasive ventilation is also effective in patients with pH of 7.35-7.30, however there is no additional benefit if pH value is greater than 7.35. The lowest threshold for effective treatment is not well-defined but has been demonstrated with success in some patients with as low as 7.10 pH.
• Obtunded patients: Obtunded COPD patients respond better to treatment, but with a lower overall success rate.
• Improved after trial: Improvement after a 1-2 trial period may suggest successful NIV treatment in some patients.

Ventilator Choice Decisions

• Factors for choice: Portability, battery life, setting capabilities, reliability, and community support are key considerations.

Full Ventilation Description

• Types: Noninvasive or invasive ventilator systems. Pressure-cycled or volume-cycled ventilators.
• Adjustments possible: Allows for pressure support, PEEP, inspiratory time, flow to be altered and manipulated.

Control Mode vs. SIMV

• Control Mode: Fully supports every breath; weaning is not possible by reducing the rate. Risk of hyperventilation in agitated patients.
• SIMV Mode: Vent synchronizes with patient efforts, patients take breaths in between ventilator breaths, and increased work of breathing compared to control mode.

Specific Ventilator Techniques - Pressure vs. Volume

• Pressure Control: Set pressure, volume is variable; better control of oxygenation, generally better for younger, non-compliant lungs.
• Volume Control: Set volume, pressure is variable; better control of ventilation, generally better for older, more compliant lungs.

Pressure Support

• Trigger mechanism: Triggered by the patient, provides inspiratory flow during inspiration.
• Mimics BiPAP mode: Given to add breaths to other modes like IMV, or alone without a set rate, creating a BiPAP-like mode.

Bilevel Mode

• Mechanism: Pressure supported ventilation that imitates the actions of BiPAP. It does not have a backup rate.
• Application: Mimicked BiPAP without a backup rate.

Supporting Equipment

• External support (PEEP): Equipment required to provide external support and pressure.
• Monitoring: Alarms, pulse oximetry, apnea monitor, capnography
• Humidification: Humidification equipment.
• External heater: External heaters for humidification use.
• HME: Heat and Moisture Exchanger.
• Airway clearance: Airway clearance equipment/techniques (suctioning, vest, cough assist, and talking devices).

Discharge Criteria

• Stable airway: The presence and maintenance of a stable airway.
• Oxygen requirements: Oxygen requirements (FiO2 less than 40%).
• Carbon dioxide levels: Maintaining carbon dioxide levels (PCO2) within a safe range.
• Nutritional intake: Meeting optimal nutritional intake.
• Other medical conditions: Other medical conditions well-controlled.
• Palliative care adjustments: above may need adjustments for palliative care patients.
• Discharged preparation: Goal clarity with family; family/respite care givers are trained for ventilator use, nursing is arranged for nighttime; equipment lists, supply, and funding issues are addressed.

Continuing Assessment

• Titration sleep studies: Titration and sleep studies need to be continued as per patient needs,.
• Blood gas analyses: Continuation of blood gas analyses are performed.
• Bronchoscopy: Bronchoscopies may be required in certain situations.
• Home monitoring: Ongoing home monitoring will be necessary through assessment and re-evaluation..
• Weaning and Decannulation: Ongoing assessment and evaluation will be necessary during weaning and decannulation.

Complications

• Ventilator failure.
• Tracheostomy related issues.
• Decannulation/blockage/infections.
• Mask-related issues.
• Pressure sores.
• Facial growth concerns.
• Under- or over-ventilation.

Outcomes

• Underlying disease dependence: Outcomes dependent on underlying disease severity and patient factors.
• High survival rates: Over 70% of patients survive 10 years after home mechanical ventilation.

Quality of Life

• Generally good: Patients often report good quality of life.
• Fewer hospitalizations: Fewer hospitalizations compared to other treatment methods..
• Better sleep quality: Improved sleep quality may be reported..
• Improved daytime functionality: Daily functionality may be improved.
• Potential caregiver stress: Some stress related for patients/caregivers are related to care and support needs.

Home Ventilation Reality

• Individualized approach: Every patient's ventilation needs are unique.
• Guidelines vs. Rules: The guidelines are helpful but not absolute rules.
• Patient goals: Goal-setting and teamwork to achieve optimal health and quality of life.

This quiz covers key topics related to respiratory failure, management strategies in high-risk patients, and best practices for mask usage in post-procedure care. Test your knowledge on pulmonary conditions and the critical factors affecting respiratory health, particularly in immunocompromised individuals.