NBRC Therapist Multiple-Choice (TMC) Practice Exam

In the context of mechanical ventilation, the principle of setting the tidal volume is crucial for ensuring adequate ventilation while minimizing the risk of ventilator-induced lung injury. For adult patients requiring mechanical ventilation, an initial tidal volume setting of 4-6 mL/kg of predicted body weight is recommended. This range is designed to provide sufficient ventilation without overdistending the lungs, which can lead to complications such as barotrauma or volutrauma.

The goal of using predicted body weight rather than actual body weight is to tailor the tidal volume to the patient's lung capacity and to mitigate the effects of obesity on ventilatory mechanics. This approach helps to optimize gas exchange while minimizing potential harm to the lungs.

In contrast, higher tidal volumes (like the 8-10 mL/kg range) may be appropriate in certain cases but can increase the risk of lung injury, especially in patients with pre-existing respiratory conditions. Therefore, starting at a lower tidal volume is generally considered a safer practice.

The other options, such as tidal volumes above this initial setting or those measured in liters per minute, do not align with the standard approach for calculating tidal volume based on body weight, emphasizing why the 4-6 mL/kg recommendation is the preferred method for initial ventilatory