# AI miscalculates IV pump rate for dopamine infusion using patient's actual body weight instead of ideal body weight, leading to potential overdose in obese patients

- **ID:** `medical/iv-pump-rate-miscalculation-weight`
- **Domain:** medical
- **Category:** runtime_error
- **Error Code:** `DOPAMINE_DOSE_IBW`
- **Verification:** ai_generated
- **Fix Rate:** 91%

## Root Cause

Dopamine dosing for hemodynamic support is based on ideal body weight (IBW) because it acts on the heart and vasculature, not on adipose tissue. Using actual body weight in obese patients (BMI >30) can result in doses 2-3 times higher than intended.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| IV-pump:Alaris-PCU-2024 | active | — | — |
| IV-pump:Baxter-Sigma-Spectrum-2023 | active | — | — |

## Workarounds

1. **Calculate ideal body weight (IBW) using the Devine formula: For males: IBW (kg) = 50 + 2.3 * (height in inches - 60). For females: IBW (kg) = 45.5 + 2.3 * (height in inches - 60). Use this IBW for dopamine dose calculation. Example: For a 5'6" female: IBW = 45.5 + 2.3 * (66 - 60) = 45.5 + 13.8 = 59.3 kg. For a dopamine drip at 5 mcg/kg/min, dose = 5 * 59.3 = 296.5 mcg/min. Convert to mL/hr based on concentration.** (95% success)
   ```
   Calculate ideal body weight (IBW) using the Devine formula: For males: IBW (kg) = 50 + 2.3 * (height in inches - 60). For females: IBW (kg) = 45.5 + 2.3 * (height in inches - 60). Use this IBW for dopamine dose calculation. Example: For a 5'6" female: IBW = 45.5 + 2.3 * (66 - 60) = 45.5 + 13.8 = 59.3 kg. For a dopamine drip at 5 mcg/kg/min, dose = 5 * 59.3 = 296.5 mcg/min. Convert to mL/hr based on concentration.
   ```
2. **If the patient's actual weight is greater than 30% above IBW, use IBW for initial dosing and titrate based on clinical response (blood pressure, heart rate). Monitor for signs of overdose (tachycardia, hypertension, arrhythmias). Re-calculate if patient's weight changes significantly.** (90% success)
   ```
   If the patient's actual weight is greater than 30% above IBW, use IBW for initial dosing and titrate based on clinical response (blood pressure, heart rate). Monitor for signs of overdose (tachycardia, hypertension, arrhythmias). Re-calculate if patient's weight changes significantly.
   ```
3. **Use a weight-based dosing calculator that explicitly asks for IBW or automatically calculates it from height and gender. Many hospital electronic medical records (EMRs) have this functionality; ensure the correct weight type is selected.** (92% success)
   ```
   Use a weight-based dosing calculator that explicitly asks for IBW or automatically calculates it from height and gender. Many hospital electronic medical records (EMRs) have this functionality; ensure the correct weight type is selected.
   ```

## Dead Ends

- **Assuming that all weight-based medications use actual body weight** — Many vasoactive drugs (dopamine, dobutamine, norepinephrine) are dosed on IBW because they do not distribute into fat. Using actual weight in obesity causes overdose. (70% fail)
- **Using a 'standard' weight of 70 kg for all adult patients to simplify calculations** — This ignores both underweight and obese patients, leading to underdosing in small patients and overdosing in large patients. IBW calculation is patient-specific. (65% fail)
- **Believing that the IV pump's built-in drug library automatically corrects for weight** — The pump's drug library requires the user to input the correct weight (IBW vs actual). If the user enters actual weight, the pump calculates based on that input, not automatically adjusting to IBW. (50% fail)