Critical Care, Mechanical Ventilation, and Airway Management Rotations

Critical Care, Mechanical Ventilation, and Airway Management Rotations

This rotation places you at the bedside of some of the most acutely ill patients in the hospital. Your role is to assist credentialed respiratory therapists (RTs) in managing mechanical ventilators, maintaining safe airways, and guiding patients toward liberation from ventilatory support. Every action you take in the ICU must be performed under continuous preceptor supervision and within your assigned scope as a student.

Setting Initial Ventilator Parameters

When a patient is placed on mechanical ventilation, the ordering provider prescribes the mode, tidal volume (Vt), respiratory rate, FiO₂, and PEEP. Your job is to translate that order into a correctly configured ventilator setup and verify that all alarms are active and appropriately set before leaving the bedside.

Common starting points for adults include a tidal volume of approximately 6–8 mL/kg of ideal body weight (IBW), with lung-protective strategies (often 6 mL/kg IBW) used for patients with or at risk for acute respiratory distress syndrome (ARDS). For neonatal and pediatric patients, parameters are calculated differently and the ranges are much smaller—always confirm with your preceptor before making any adjustment.

After initiation, assess the patient: observe chest rise, auscultate bilaterally, check SpO₂ and ETCO₂, and document your baseline findings.

Interpreting Waveforms and Alarm Conditions

Modern ventilators display pressure–time, flow–time, and volume–time waveforms. Key patterns to recognize include:

• Flow starvation: the patient's inspiratory effort exceeds the set flow, causing a scooped pressure waveform—signals a need to increase flow or change mode.
• Auto-PEEP (intrinsic PEEP): incomplete exhalation shown by a non-zero flow at end-expiration—common in obstructive disease; increases risk of air trapping and hemodynamic compromise.
• Dyssynchrony: mismatches between patient effort and ventilator delivery, visible as irregular waveform patterns.

When an alarm activates, follow a systematic DOPE approach as a first check: Displacement, Obstruction, Pneumothorax, Equipment failure. Never silence an alarm without identifying and correcting its cause.

Calculating Static Compliance and Airway Resistance

These two measurements help you assess the mechanical properties of the respiratory system.

Static compliance (Cst) reflects lung and chest wall distensibility:

> Cst = Vt ÷ (Plateau pressure − PEEP)

Normal adult Cst is roughly 60–100 mL/cmH₂O. Decreasing compliance suggests worsening lung stiffness (e.g., ARDS, pulmonary edema).

Airway resistance (Raw) reflects opposition to airflow in the conducting airways:

> Raw = (Peak inspiratory pressure − Plateau pressure) ÷ Flow (L/s)

Elevated resistance may indicate bronchospasm, secretions, or a kinked or too-small endotracheal tube. Reporting trends to the supervising therapist helps guide bronchodilator therapy and airway care.

Adjusting FiO₂ and PEEP

Adjustments to FiO₂ and PEEP are made to optimize oxygenation while minimizing oxygen toxicity and ventilator-induced lung injury. You make no adjustment without explicit direction from the supervising therapist. After any change, reassess SpO₂, hemodynamics, and patient comfort within a few minutes and document the time, the change made, and the patient's response.

Non-invasive ventilation (NIV) modes—BiPAP and CPAP—are used for patients who can protect their airway and maintain some respiratory drive. Proper mask fit is essential; pressure points, leaks, and patient tolerance must be reassessed every visit.

Airway Management

As a student you will observe, assist, or perform assigned portions of airway procedures. Key safety rules:

• Cuff pressure should be maintained in the range recommended by your program and AARC guidelines—typically 20–30 cmH₂O—to prevent aspiration above the cuff and tracheal mucosal injury from excessive pressure. Measure with a calibrated cuff manometer, not by feel.
• Suctioning is performed only when clinically indicated (not on a fixed schedule), using appropriate catheter size and suction pressure, with pre- and post-oxygenation as needed.
• After any intubation or tube repositioning, confirm placement by auscultation, waveform capnography, and chest X-ray before securing the tube.
• Tracheostomy care follows sterile or clean technique per facility policy; report any signs of site infection or tube displacement immediately.

Always have a manual resuscitator (BVM) connected to oxygen within arm's reach of every ventilated patient.

Spontaneous Awakening Trials and Spontaneous Breathing Trials

Ventilator liberation is a collaborative process. The SAT (spontaneous awakening trial) involves the nursing team reducing or stopping sedation; the SBT (spontaneous breathing trial) tests whether the patient can sustain adequate breathing with minimal or no ventilator support.

Your role is to perform the readiness screen: check pass/fail safety criteria, then calculate the Rapid Shallow Breathing Index (RSBI):

> RSBI = Respiratory rate (breaths/min) ÷ Tidal volume (liters)

An RSBI below 105 breaths/min/L is generally associated with successful weaning, though clinical judgment and the full patient picture guide the final decision. Document your RSBI result, whether the patient met pass criteria, and your recommendation—then discuss with the supervising therapist before any order is placed.

Safety and Professional Conduct

• Stop and notify your preceptor immediately if a patient deteriorates, a device malfunctions, or you are unsure of any step.
• You may not independently adjust a ventilator, perform airway procedures, or enter orders—these require a licensed RT and/or provider.
• Document every intervention accurately and promptly; falsifying or omitting clinical records is a serious violation with legal and licensure consequences.
• Maintain standard precautions and follow your site's infection-control protocols for all airway work.