RRT-ACCS common mistakes
RRT-ACCS · Understand the traps and how to avoid them.
Labels an ABG as a single primary disorder without running the compensation check - e.g., calls a pH 7.22/PaCO2 28/HCO3 11 a 'respiratory alkalosis' or 'mixed' disorder instead of a primary metabolic acidosis with appropriate respiratory compensation.
Candidates pattern-match on the single most abnormal number (usually the PaCO2) instead of working the algorithm: pH first, then primary driver, then expected compensation, then anion gap and delta ratio.
What to do instead
Before answering any acid-base item, write out four lines on scratch paper: (1) pH acidemic/alkalemic, (2) primary disorder from the direction of PaCO2 vs HCO3, (3) expected compensation from the standard formulas (Winter's, 0.7/1.0/0.1 rules), (4) gap and delta-delta if metabolic acidosis. Only then read the answer options.
Attributes a rising peak airway pressure to 'decreased compliance' and reaches for a bronchodilator or a PEEP change without ever computing the plateau pressure or looking at the flow-time scalar.
Peak pressure is the number displayed most prominently; candidates skip the PIP-minus-Pplat step and skip scanning the flow tracing for auto-PEEP or the pressure-time curve for a swallowed/effort breath.
What to do instead
Train a fixed sequence for every high-pressure item: check Pplat and compute the gradient. Gradient >5-10 cmH2O points to resistance (secretions, bronchospasm, kinked or bitten tube); a high Pplat with a normal gradient points to compliance (ARDS, pneumothorax, mainstem intubation, abdominal distension). Confirm auto-PEEP by an expiratory hold or by expiratory flow that does not return to zero before the next breath.
Computes derived oxygenation/shunt indices with the wrong assumptions - e.g., calculates a P/F ratio on a patient on 100% oxygen and calls it ARDS, or computes an A-a gradient using an assumed FiO2 that is not the one in the stem.
Formulas are memorized as isolated equations without the qualifying conditions: P/F staging assumes PEEP of at least 5 cmH2O, and PAO2 requires the actual inspired oxygen, barometric pressure, and an RQ of 0.8.
What to do instead
Attach the conditions to the formula when you memorize it: PAO2 = FiO2(Pb - 47) - PaCO2/0.8; A-a gradient only meaningful on the stated FiO2; P/F only interpretable with a documented PEEP of 5 cmH2O or more and no confounding (e.g., altitude, methemoglobin). Re-derive the number from stem values rather than recalling a 'typical' value.
Sets tidal volume from the documented actual body weight - e.g., programs 8 mL/kg on a 110 kg patient, yielding roughly 880 mL, and then defends it as '8 mL/kg.'
The stem supplies a weight and the mental shortcut is to multiply it; predicted body weight requires height and sex, and the formula is often only vaguely remembered under time pressure.
What to do instead
Memorize predicted body weight: male = 50 + 2.3(inches over 60); female = 45.5 + 2.3(inches over 60). Compute it explicitly on scratch paper before touching the tidal volume, then target 6 mL/kg PBW initially (range 4-8) with plateau pressure at or below 30 cmH2O. Treat any option that states a volume in mL/kg of actual weight as a distractor.
Sees a hypotensive, tachypneic, obstructed patient with a rising pressure tracing and increased PEEP is chosen as the fix, or a tidal volume is left unchanged while the team searches for a cause.
Auto-PEEP is treated as a waveform curiosity rather than a hemodynamic emergency; candidates do not connect breath stacking to reduced venous return and obstructive shock.
What to do instead
When the scenario shows an obstructed or tachypneic patient with hypotension, the priority is to reduce hyperinflation: increase expiratory time (lower rate, higher inspiratory flow, shorter inspiratory time), treat the obstruction, and disconnect from the ventilator briefly to allow a full exhalation. Recognize that the hypotension resolves with exhalation, not with fluid or higher PEEP.
Continues noninvasive ventilation or high-flow oxygen in a patient who is failing, or conversely intubates a patient who is not yet a failure, because the decision is based on the starting numbers rather than a reassessment interval.
Candidates fixate on the mode choice and forget that NIV and high-flow trials have defined reassessment windows and defined failure predictors (no improvement in pH or PaCO2, persistent tachypnea, rising work of breathing, inability to protect the airway).
What to do instead
Build an explicit 30-120 minute reassessment checkpoint into every NIV/high-flow item: gas exchange, respiratory rate and work of breathing, mental status, hemodynamics, and patient tolerance. If the prespecified endpoints are not met, escalate to intubation rather than prolonging the trial.
Declares a patient ready for extubation on the basis of a passing ABG or a passing spontaneous breathing trial alone, ignoring cough strength, secretion burden, cuff leak, and mental status.
The SBT and the gas are the most visible data in the stem; the airway and secretion assessment is scattered across the history and easy to overlook.
What to do instead
Use a checklist for every extubation item: passed SBT, adequate cough, manageable secretions (and suction frequency), cuff leak present when risk factors for edema exist, Richmond Agitation-Sedation Scale in an acceptable range, and hemodynamic stability. If any element is missing, the correct answer is usually to address that element rather than to extubate.
In an alarm or deterioration scenario, troubleshoots the device first - checks the circuit, swaps a flow sensor, calls biomedical engineering - while the patient remains unventilated.
The question is presented as an equipment problem because the alarm is an equipment alarm, and candidates answer the question that was described rather than the question that was asked (what do you do first?).
What to do instead
Anchor on the rule that the patient is evaluated before the machine: disconnect from the ventilator and manually ventilate with a bag-valve (with PEEP valve and, if indicated, 100% oxygen), assess for displacement, obstruction, pneumothorax, equipment failure, and stacking (DOPES), then return to the ventilator once the patient is stable.
Manages the ventilator circuit in ways that break the VAP prevention bundle - schedules a routine circuit change every 48-72 hours, disconnects the circuit to suction, or keeps the humidifier filled from a bag that has been at room temperature.
Older habit patterns and a focus on the ventilator settings rather than the infection-prevention practices that surround them; the bundle elements are learned as a list but not applied when the item is framed as a ventilator-management question.
What to do instead
Memorize the bundle as behaviors rather than a slogan: change circuits only when visibly soiled or malfunctioning, use closed suction when available and do not break the circuit routinely, keep the head of bed at 30-45 degrees, use sterile technique with condensate drained away from the patient, and provide daily sedation interruption with spontaneous breathing assessment.
Chooses the definitive treatment or the diagnostic study when the item asks for the immediate next action in an unstable patient, or chooses the stabilizing step when the patient is stable and the question asks for the diagnosis.
The stem is read for the clinical diagnosis and the last line is read too quickly; candidates answer 'the right thing to do' instead of 'the right thing to do next, given the stability described.'
What to do instead
Re-read the final clause of every stem and underline the time qualifier (first, next, most appropriate, initial). Then triage the options into stabilization steps versus definitive steps and select the one that matches the time frame and the stability described in the vignette.