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Respiratory Therapy · Therapeutic Intervention

Noninvasive Ventilation and Specialized Respiratory Therapies

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On this page 7 sections
  1. In 30 seconds
  2. Why this matters
  3. The college version
  4. Eli explains
  5. Worked example
  6. Key takeaway
  7. Study tools

In 30 seconds

delivers positive pressure through a mask or interface rather than an artificial airway. Bi-level NIV pairs an inspiratory pressure () that assists each breath with an expiratory pressure () that holds airways open, used mainly for COPD exacerbation, cardiogenic pulmonary edema, and patients who decline intubation (DNI). applies one constant pressure to splint the upper airway open in . is a selective pulmonary vasodilator requiring and monitoring; heliox (80/20 or 70/30 helium-oxygen) lowers gas density to cut airway resistance; is given prophylactically or as rescue for neonatal respiratory distress syndrome.

Why this matters

The therapist's role is assessment, monitoring, and implementation per order and protocol—not independent selection of pressures, gas blends, or medications. Inhaled nitric oxide, heliox, and surfactant are high-consequence therapies demanding meticulous monitoring. All pressure targets, gas concentrations, correction factors, monitoring thresholds, and practices here are conceptual and educational only; they must be verified against the current NBRC detailed content outline, candidate handbook, AARC clinical practice guidelines, facility protocols, state licensure requirements, provider orders, and manufacturer instructions for use (IFU).

The college version

1. NIV indications and pressure concepts

NIV applies positive pressure through a mask (nasal, oronasal, full-face, or helmet) without an endotracheal tube or tracheostomy. The three exam-highlighted indications:

  • COPD exacerbation — bi-level NIV lowers work of breathing, improves alveolar ventilation, and reduces PaCO2 in acute hypercapnic respiratory failure.
  • Cardiogenic pulmonary edema / CHF — CPAP or bi-level decreases preload and afterload on the failing heart and recruits flooded alveoli.
  • DNI — for a patient who declines intubation, NIV is a ceiling-of-care support to relieve dyspnea, not a substitute for invasive ventilation.

IPAP (inspiratory positive airway pressure) is the pressure during inspiration—the ventilatory assist (larger tidal volume, more CO2 removal). EPAP (expiratory positive airway pressure) is the baseline pressure during expiration—it recruits alveoli and improves oxygenation, functionally like PEEP, and offsets intrinsic PEEP. Their difference (IPAP − EPAP) is the effective pressure support. CPAP is one unchanging pressure all cycle long; it does not actively assist ventilation but keeps the upper airway and alveoli open—the core therapy for OSA, repetitive upper-airway collapse during sleep.

2. Inhaled nitric oxide

Inhaled nitric oxide (iNO) selectively relaxes pulmonary vascular smooth muscle only in the ventilated alveoli it reaches, improving ventilation-perfusion matching and lowering pulmonary artery pressure without systemic hypotension. Its classic use is persistent pulmonary hypertension of the newborn (PPHN). Two monitors are essential: nitrogen dioxide (NO2), a toxic byproduct formed when NO meets oxygen (a delivery-side hazard), and methemoglobin, NO-bound hemoglobin that cannot carry oxygen (a patient-side hazard). Weaning is gradual as oxygenation improves, because abrupt withdrawal can cause rebound pulmonary hypertension.

3. Heliox and surfactant replacement

Heliox mixes helium (about one-seventh the density of air) with oxygen, reducing turbulent airflow resistance through narrowed airways. Common blends are 80/20 (80% helium / 20% oxygen) and 70/30 (70% helium / 30% oxygen). The key equipment concept is : a standard oxygen flowmeter, calibrated for denser air/oxygen, under-reads with helium—the actual flow is higher than the gauge shows, so a correction factor (about 1.8 for 80/20, 1.6 for 70/30) is applied.

Surfactant replacement supplies exogenous surfactant to premature neonates whose immature lungs produce too little, causing respiratory distress syndrome (RDS) with alveolar collapse. Prophylactic administration is given shortly after birth to high-risk infants before significant disease; rescue (treatment) is given after RDS is established.

How it works

  1. A blower delivers positive pressure through a sealed or vented interface.
  2. Bi-level pressure rises to IPAP on inspiration and falls to EPAP on expiration.
  3. IPAP adds volume and unloads muscles; EPAP maintains patency at end-expiration; CPAP holds one pressure to keep the airway or alveoli open.
  4. iNO dilates vessels only where gas reaches; helium lowers density; surfactant coats alveoli to reduce surface tension.

Common confusions

Do not confuseWithDifference
IPAPEPAPIPAP acts during inspiration (ventilation); EPAP during expiration (oxygenation/patency)
CPAPBi-level (IPAP/EPAP)CPAP is one constant pressure; bi-level has two
NIVInvasive ventilationNIV uses a mask, no airway; cannot protect airway or ventilate apnea
Heliox 80/20Heliox 70/3080/20 has more helium (less density); 70/30 delivers more oxygen
Prophylactic surfactantRescue surfactantProphylactic is before disease; rescue is after
NO2MethemoglobinNO2 is a delivery byproduct; methemoglobin is a blood effect

Memory aids

"IPAP Inspires, EPAP Expires." IPAP pushes air in with inspiration; EPAP props the airway open during expiration.

Quick review

Topic Recap

NIV supports breathing through a mask without an artificial airway. Bi-level pairs IPAP (inspiratory/ventilation) with EPAP (expiratory/oxygenation) for COPD exacerbation, cardiogenic pulmonary edema, and DNI; CPAP holds one pressure to treat OSA and recruit alveoli in CHF. Specialized therapies each carry a signature concept: iNO needs NO2 and methemoglobin monitoring with gradual weaning; heliox lowers gas density and needs flowmeter correction; surfactant is prophylactic (before RDS) or rescue (after RDS).

Knowledge Check

  1. Which bi-level pressure component functions most like PEEP?
  2. Which single-pressure mode is used for OSA?
  3. Why must a standard flowmeter be corrected when heliox is delivered?
  4. Which two values are monitored for safety in iNO therapy?
  5. Surfactant given shortly after birth before RDS develops is classified as what?

Answers and Rationales

  1. EPAP — the expiratory baseline pressure that recruits alveoli and improves oxygenation, like PEEP.
  2. CPAP — one constant pressure splints the collapsing airway open.
  3. Because helium is less dense than air, the flowmeter under-reads; actual flow is higher, so a correction factor is applied.
  4. NO2 and methemoglobin — delivery-system toxicity and reduced blood oxygen-carrying capacity.
  5. Prophylactic — given before significant disease; rescue occurs after RDS is established.
Eli, the EliExplains learning guide

Eli explains

The same idea, in plain words

Explain it like I’m 10

NIV is like a fan that keeps a floppy straw open by blowing air through it, instead of forcing a rigid pipe down its center. The machine assists a person's own breaths through a snug mask rather than taking over breathing like an invasive ventilator. Bi-level support is a helper who pushes harder while you breathe in (IPAP) and eases off—but not all the way—while you breathe out (EPAP), so the airways never fully collapse. CPAP is a steady breeze that simply prevents collapse during sleep.

Where this stops being exact: NIV cannot protect the airway or ventilate someone who is apneic, and the actual pressure numbers are clinician-selected, so this note stays at what each pressure does, not what to set.

Simple Example

A person in a COPD flare works hard to breathe with a rising CO2. A bi-level mask pushes a bigger breath in (IPAP, lowering CO2 and effort) while EPAP keeps small airways propped open to empty fully. At a single pressure (CPAP), the same idea holds a person's throat open through the night in OSA.

Worked example

  1. Recognize the failure type. Ventilation failure (rising PaCO2, fatigue, COPD pattern) points to bi-level; airway-collapse or alveolar-recruitment problems point to CPAP.
  2. Match pressure to the job. IPAP addresses ventilation; EPAP addresses oxygenation and patency. This is the cleanest way to keep them straight.
  3. Read the safety monitors as a pair. For iNO, NO2 is the delivery-side hazard and methemoglobin the patient-side hazard; expect gradual weaning. For heliox, remember the gauge under-reads.
  4. Classify surfactant by timing. Prophylactic = before disease (delivery room); rescue = after RDS is diagnosed.

Key takeaways

  • High yield: IPAP = inspiratory/ventilation; EPAP = expiratory/oxygenation; their difference is the pressure support.
  • High yield: COPD exacerbation and cardiogenic pulmonary edema are the classic NIV indications; DNI is ceiling-of-care, not guaranteed success.
  • High yield: CPAP does not actively assist ventilation—it maintains airway patency (OSA) and recruits alveoli (CHF).
  • High yield: Heliox flowmeters under-read; actual flow is higher than indicated.
  • High yield: Monitor NO2 and methemoglobin together for iNO; wean gradually to avoid rebound.
  • High yield: Prophylactic surfactant = before RDS; rescue = after RDS.

Keep learning

Ready to build on this? Continue to the next lesson.

Practice Respiratory Therapy

This lesson has no separate scored set. Practice draws from the subject’s question bank.

Study tools & related lessonsYou’ll learn to · Key vocabulary · Related

You’ll learn to

  • Identify the primary indications for noninvasive ventilation (NIV): COPD exacerbation, cardiogenic pulmonary edema/CHF, and do-not-intubate (DNI) situations.
  • Distinguish IPAP from EPAP and explain the role of CPAP in obstructive sleep apnea (OSA).
  • Describe the monitoring concepts for inhaled nitric oxide (NO2 and methemoglobin) and the rationale for heliox mixtures and flowmeter correction.
  • Contrast prophylactic and rescue surfactant replacement.

Key vocabulary

NIV
Positive pressure via mask, no artificial airway
IPAP
Inspiratory pressure assisting each breath
EPAP
Expiratory baseline pressure (PEEP-like)
CPAP
One constant pressure all cycle
OSA
Repetitive upper-airway collapse in sleep
Inhaled nitric oxide
Selective pulmonary vasodilator gas
NO2
Toxic NO + oxygen byproduct
Methemoglobin
NO-bound, non-oxygen-carrying hemoglobin
Heliox 80/20 / 70/30
80% or 70% helium with oxygen
Flowmeter correction
Adjusting gauge reading for helium
Surfactant replacement
Exogenous surfactant for neonatal RDS
Prophylactic vs rescue
Before vs after RDS develops

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