How should induction and paralysis dosing be adjusted in obese or pregnant patients?

• A. Always use fixed doses regardless of weight
• B. Use lower doses only
• C. Use weight-based dosing with consideration of body habitus; consider ideal body weight for tidal volumes; adjust for pregnancy hemodynamics and airway edema
• D. Avoid induction in obese and pregnant patients

Answer: (C)

In obese or pregnant patients, dosing for induction and paralysis must be individualized based on body size and physiologic changes, not fixed amounts. Obesity changes how drugs distribute and are cleared because there’s a larger volume in which the drug can distribute and changes in organ perfusion and protein binding. Pregnancy adds its own shifts: expanded plasma volume and cardiac output alter distribution and clearance, and airway edema plus faster oxygen consumption change both how you optimize induction and how you secure the airway.

So, dosing should be weight-based and tailored to the person’s body habitus, rather than a one-size-fits-all amount. Use ideal body weight (rather than total body weight) when setting tidal volumes for ventilation to protect the lungs, and adjust induction and paralysis considering the pregnancy-related hemodynamic changes and potential airway edema. The key is titrating to effect with careful airway and hemodynamic monitoring, rather than relying on fixed doses.