bsa_calculator.py•9.26 kB
"""
Body Surface Area (BSA) Calculator
体表面积计算器的 FastMCP 2.0 实现
"""
import math
from typing import Dict, Any
from medcalc import (
BaseCalculator,
CalculatorInfo,
Parameter,
ParameterType,
ValidationResult,
CalculationResult,
register_calculator
)
from medcalc.utils import round_number
@register_calculator("bsa")
class BSACalculator(BaseCalculator):
"""体表面积计算器实现"""
def get_info(self) -> CalculatorInfo:
return CalculatorInfo(
id=60,
name="Body Surface Area (BSA)",
category="anthropometry",
description="Calculate body surface area using the Mosteller formula",
parameters=[
Parameter(
name="height",
type=ParameterType.NUMERIC,
required=True,
unit="cm",
min_value=30,
max_value=300,
description="Height in centimeters"
),
Parameter(
name="weight",
type=ParameterType.NUMERIC,
required=True,
unit="kg",
min_value=1,
max_value=500,
description="Weight in kilograms"
),
Parameter(
name="height_unit",
type=ParameterType.CHOICE,
required=False,
default="cm",
choices=["cm", "m", "in", "ft"],
description="Unit for height"
),
Parameter(
name="weight_unit",
type=ParameterType.CHOICE,
required=False,
default="kg",
choices=["kg", "g", "lb", "lbs", "oz"],
description="Unit for weight"
)
]
)
def _parse_parameter(self, value: Any) -> tuple[float, str]:
"""解析参数，支持字符串格式如 '175cm' 或 '70kg'"""
if isinstance(value, (int, float)):
return float(value), ""
if isinstance(value, str):
import re
# 匹配数字和单位
match = re.match(r'^([0-9]*\.?[0-9]+)\s*([a-zA-Z]*)$', value.strip())
if match:
num_str, unit = match.groups()
return float(num_str), unit.lower()
# 处理英制高度格式如 "5ft 9in"
ft_in_match = re.match(r'^([0-9]+)\s*ft\s*([0-9]+)\s*in$', value.strip())
if ft_in_match:
feet, inches = ft_in_match.groups()
total_inches = int(feet) * 12 + int(inches)
return float(total_inches), "in"
raise ValueError(f"Cannot parse parameter value: {value}")
def _get_height_explanation(self, value: float, unit: str, height_cm: float) -> str:
"""生成高度转换的解释说明"""
if unit == "cm":
return f"The patient's height is {value} cm."
elif unit == "m":
return f"The patient's height is {value} m, which is {value} m * 100 cm/m = {height_cm} cm."
elif unit == "ft":
return f"The patient's height is {value} ft, which is {value} ft * 30.48 cm/ft = {height_cm} cm."
elif unit == "in":
return f"The patient's height is {value} in, which is {value} in * 2.54 cm/in = {height_cm} cm."
else:
return f"The patient's height is {height_cm} cm."
def _get_weight_explanation(self, value: float, unit: str, weight_kg: float) -> str:
"""生成重量转换的解释说明"""
if unit == "kg":
return f"The patient's weight is {value} kg."
elif unit in ["lb", "lbs"]:
return f"The patient's weight is {value} lbs so this converts to {value} lbs * 0.453592 kg/lbs = {weight_kg} kg."
elif unit == "g":
return f"The patient's weight is {value} g so this converts to {value} g * 1 kg/1000 g = {weight_kg} kg."
elif unit == "oz":
return f"The patient's weight is {value} oz so this converts to {value} oz * 0.0283495 kg/oz = {weight_kg} kg."
else:
return f"The patient's weight is {weight_kg} kg."
def validate_parameters(self, params: Dict[str, Any]) -> ValidationResult:
"""验证输入参数"""
errors = []
warnings = []
# 检查必需参数
if "height" not in params:
errors.append("Height is required")
if "weight" not in params:
errors.append("Weight is required")
if errors:
return ValidationResult(is_valid=False, errors=errors)
# 验证数值范围（考虑单位转换）
for param_name in ["height", "weight"]:
if param_name in params:
try:
value, unit = self._parse_parameter(params[param_name])
except ValueError as e:
errors.append(f"Invalid {param_name} format: {e}")
continue
# 获取单位并转换为标准单位进行验证
if param_name == "height":
height_unit = unit or params.get("height_unit", "cm")
try:
# 转换为厘米进行验证
height_cm = self.unit_converter.convert(value, height_unit, "cm")
if height_cm < 30 or height_cm > 300:
errors.append(f"Height {value} {height_unit} is outside valid range (30-300 cm)")
except ValueError as e:
errors.append(f"Invalid height unit: {height_unit}")
elif param_name == "weight":
weight_unit = unit or params.get("weight_unit", "kg")
try:
# 转换为千克进行验证
weight_kg = self.unit_converter.convert(value, weight_unit, "kg")
if weight_kg < 1 or weight_kg > 500:
errors.append(f"Weight {value} {weight_unit} is outside valid range (1-500 kg)")
# 添加警告（使用转换后的数值）
if weight_kg > 200:
warnings.append("Weight is very high, please verify")
except ValueError as e:
errors.append(f"Invalid weight unit: {weight_unit}")
return ValidationResult(
is_valid=len(errors) == 0,
errors=errors,
warnings=warnings
)
def calculate(self, params: Dict[str, Any]) -> CalculationResult:
"""计算体表面积"""
# 验证参数
validation = self.validate_parameters(params)
if not validation.is_valid:
raise ValueError(f"Invalid parameters: {', '.join(validation.errors)}")
# 解析参数值
height_value, height_unit_parsed = self._parse_parameter(params["height"])
weight_value, weight_unit_parsed = self._parse_parameter(params["weight"])
# 获取单位（优先使用解析出的单位）
height_unit = height_unit_parsed or params.get("height_unit", "cm")
weight_unit = weight_unit_parsed or params.get("weight_unit", "kg")
# 转换为标准单位（cm, kg）
height_cm = self.unit_converter.convert(height_value, height_unit, "cm")
weight_kg = self.unit_converter.convert(weight_value, weight_unit, "kg")
# 使用 Mosteller 公式计算体表面积
# BSA = sqrt((weight * height) / 3600)
bsa = math.sqrt((weight_kg * height_cm) / 3600)
bsa_rounded = round_number(bsa)
# 构建解释说明（遵循原始代码风格）
height_explanation = self._get_height_explanation(height_value, height_unit, height_cm)
weight_explanation = self._get_weight_explanation(weight_value, weight_unit, weight_kg)
explanation = (
f"For the body surface area computation, the formula is sqrt((weight (in kgs) * height (in cm))/3600), "
f"where the units of weight is in kg and the units of height is in cm.\n\n"
f"{height_explanation}\n"
f"{weight_explanation}\n\n"
f"Therefore, the patient's BSA is sqrt(({weight_kg} (in kgs) * {height_cm} (in cm))/3600) = "
f"sqrt({weight_kg * height_cm}/3600) = sqrt({weight_kg * height_cm / 3600:.4f}) = {bsa_rounded} m²."
)
return CalculationResult(
value=bsa_rounded,
unit="m²",
explanation=explanation,
metadata={
"height_cm": height_cm,
"weight_kg": weight_kg,
"formula": "Mosteller",
"original_height": f"{height_value} {height_unit}",
"original_weight": f"{weight_value} {weight_unit}"
}
)