4.3 Specialty Procedures
Key Takeaways
- Chest tubes drain air or fluid from the pleural space through a three-chamber system; the water seal is filled to about 2 cm and suction control is typically set at -20 cmH2O
- Tidaling in the water seal is normal and confirms a patent tube; continuous bubbling signals an air leak; never clamp a chest tube without a physician order (risk of tension pneumothorax)
- Arterial sampling: perform the modified Allen test first, use a pre-heparinized syringe, expel air bubbles immediately, hold pressure 5+ minutes, and ice the sample if analysis is delayed beyond 15 minutes
- Air bubbles in an ABG falsely raise PaO2 and falsely lower PaCO2 by equilibrating with room air
- During bronchoscopy the RT manages the airway and continuously monitors SpO2, ETCO2, ECG, and vitals while assisting with lavage and biopsy
- Polysomnography records EEG, EOG, EMG, ECG, airflow, respiratory effort, SpO2, position, and snoring; the Apnea-Hypopnea Index grades OSA severity
- CPAP is the gold-standard treatment for obstructive sleep apnea, with titration typically between 5 and 20 cmH2O
- Neonatal/pediatric care: surfactant via the ETT for RDS, neonatal/bubble CPAP, HFOV at 180-900 breaths/min, uncuffed ETT = (age/4)+4, and the pediatric assessment triangle
Chest Tubes and Arterial Sampling
Respiratory therapists assist with and perform a range of specialized procedures, and the TMC exam probes the indications, technique, monitoring, and complication recognition for each. Master the normal-versus-abnormal findings — that is where the scored questions live.
Chest Tube Management
A chest (thoracostomy) tube drains air, blood, or fluid from the pleural space. Indications include pneumothorax (spontaneous, traumatic, iatrogenic), pleural effusion, hemothorax, empyema, and post-thoracic-surgery drainage. The classic disposable drainage unit has three chambers:
| Chamber | Function |
|---|---|
| Collection | Collects and measures drained fluid |
| Water seal | Filled to ~2 cm of water; one-way valve preventing air re-entry |
| Suction control | Regulates applied negative pressure, typically -20 cmH2O |
RT responsibilities and the findings you must interpret:
- Tidaling (water-seal level rising with inspiration and falling with expiration in a spontaneously breathing patient) is normal and confirms a patent tube. Loss of tidaling can mean the lung has re-expanded or the tube is obstructed or kinked.
- Continuous bubbling in the water seal signals an air leak — at the patient (ongoing pneumothorax, bronchopleural fistula) or in the system (loose connections). Intermittent bubbling with cough or exhalation can be normal.
- Keep the unit below chest level to prevent fluid back-flow.
- Never clamp a chest tube without a physician order — clamping a tube with an active air leak can cause a tension pneumothorax.
- Report sudden cessation of drainage, new respiratory distress, or subcutaneous emphysema (crepitus).
Arterial Blood Sampling (ABG Draw)
Begin with the modified Allen test to confirm collateral ulnar circulation: the patient clenches the fist while you occlude both the radial and ulnar arteries; the open hand blanches; you release the ulnar artery while holding radial pressure. A positive (normal) test is re-coloring within 5-15 seconds — proceed. If the hand stays blanched (negative test), do not puncture the radial artery on that side.
Use a pre-heparinized syringe, puncture the radial artery at ~45 degrees (brachial 60 degrees, femoral 90 degrees), and let arterial pressure fill the barrel without forceful aspiration. Expel all air bubbles immediately — trapped room air equilibrates with the blood and falsely raises PaO2 and falsely lowers PaCO2. Hold firm pressure for at least 5 minutes (15+ minutes if anticoagulated), and ice the sample only if analysis will be delayed beyond ~15 minutes; otherwise run it promptly.
Bronchoscopy, Sleep Studies, and Neonatal/Pediatric Care
Bronchoscopy Assistance
During flexible bronchoscopy the RT is the airway and monitoring lead. Responsibilities: manage the airway (especially in the intubated patient, where the scope passes through a swivel adapter while ventilation continues), continuously monitor SpO2, ETCO2, ECG, and vital signs, deliver supplemental oxygen, assist with topical lidocaine anesthesia, and help collect specimens via bronchoalveolar lavage (BAL), brushings, and biopsy. Watch for and report procedural complications — hypoxemia, bronchospasm, bleeding, laryngospasm, and pneumothorax (particularly after transbronchial biopsy).
Polysomnography (Sleep Studies)
A full attended polysomnogram (PSG) records multiple channels simultaneously:
| Channel | Measurement | Purpose |
|---|---|---|
| EEG | Brain waves | Stage sleep |
| EOG | Eye movement | Identify REM |
| EMG | Chin/leg muscle tone | REM atonia, leg movements |
| ECG | Heart rhythm | Arrhythmias |
| Airflow | Nasal/oral breathing | Detect apneas/hypopneas |
| Effort | Thoracic/abdominal bands | Obstructive vs. central events |
| SpO2 | Oxygen saturation | Desaturations |
| Position | Body orientation | Positional apnea |
| Snoring mic | Sound | Snoring severity |
Apneas and hypopneas are summed into the Apnea-Hypopnea Index (AHI) — events per hour of sleep:
| AHI | OSA Severity |
|---|---|
| <5 | Normal |
| 5-14 | Mild |
| 15-29 | Moderate |
| >=30 | Severe |
CPAP is the gold-standard treatment for obstructive sleep apnea; it pneumatically splints the upper airway open. Effective pressure (typically 5-20 cmH2O) is set during a titration study. The exam distinguishes obstructive events (effort present, airflow absent) from central events (both effort and airflow absent).
Neonatal and Pediatric Considerations
| Topic | Key Points |
|---|---|
| Surfactant | Given via the ETT for neonatal RDS; INSURE (Intubate-Surfactant-Extubate) or LISA (Less Invasive Surfactant Administration) |
| Neonatal CPAP | First-line for preterm RDS; bubble CPAP or ventilator CPAP |
| HFOV | Tiny tidal volumes at 180-900 breaths/min (3-15 Hz); gas exchange by enhanced diffusion, not bulk flow; for refractory failure |
| ETT sizing | Uncuffed = (age/4) + 4; cuffed = (age/4) + 3.5; term neonate 3.0-3.5 mm |
| Drug dosing | Weight-based (mg/kg); use the Broselow tape in emergencies |
| Pediatric assessment triangle | Appearance, Work of Breathing, Circulation to skin — a rapid first-look tool |
For a 4-year-old, the uncuffed tube is (4/4) + 4 = 5.0 mm; always stock one size larger and one smaller. Cuffed tubes are increasingly used even in young children, but the exam still tests the classic uncuffed formula. Confirm placement by bilateral chest rise, equal breath sounds, and color-change end-tidal CO2 detection, then secure and obtain a chest radiograph; the tip should sit above the carina (about T2-T3 in a neonate).
Apgar Scoring and Neonatal Resuscitation
Neonatal questions often pair specialty procedures with assessment. The Apgar score, recorded at 1 and 5 minutes, grades five signs — Appearance (color), Pulse (heart rate), Grimace (reflex), Activity (tone), and Respirations — from 0 to 2 each for a maximum of 10. A heart rate below 100/min prompts positive-pressure ventilation, and a heart rate below 60/min despite 30 seconds of effective ventilation triggers chest compressions coordinated 3:1 with breaths.
The most important first intervention in neonatal distress is establishing effective ventilation, not oxygen alone or compressions, because most neonatal arrests are respiratory in origin — a frequently tested distinction from adult resuscitation.
Before performing a radial artery puncture for ABG sampling, the respiratory therapist should perform the:
When observing a chest drainage system, continuous air bubbles in the water seal chamber indicate:
An AHI (Apnea-Hypopnea Index) of 22 events per hour on a sleep study indicates:
For a 4-year-old child, what size UNCUFFED endotracheal tube is appropriate?
Which of the following are monitored during a polysomnography (PSG) sleep study? (Select all that apply)
Select all that apply
During an ABG draw, air bubbles in the sample will cause which of the following errors?
High-frequency oscillatory ventilation (HFOV) is characterized by:
A patient on a closed in-line suction system is being suctioned through the endotracheal tube. The MOST important reason to use a closed (in-line) system rather than an open technique in a ventilated patient is that it: