A 70-year-old man comes to the emergency room for worsening leg pain and a rash consistent with wet gangrene. He has no history of skin infections but has type 2 diabetes mellitus and has smoked 2 packs of cigarettes daily for 20 years. Three days after admission, he becomes increasingly hypoxic and tachypneic. He is emergently intubated and ventilatory support is initiated. He is 180 cm (5 ft 11 in) tall and weighs 90 kg (198 lb); BMI is 27.8 kg/m2. His pulse is 112/min and his blood pressure is 95/60 mmHg. The ventilator is set at an FIO2 of 100%, tidal volume of 540 mL, respiratory rate of 20/min, and positive end-expiratory pressure (PEEP) of 5 cm H2O. On pulmonary examination, there are diffuse crackles. Cardiac examination shows no abnormalities. Hemoglobin is 11.5 g/dL, serum lactate is 4.0 mmol/L, and serum creatinine is 2.5 mg/dL. An arterial blood gas checked 30 minutes after intubation shows a PaCO2 of 50 mm Hg and a PaO2 of 55 mm Hg. An x-ray of the chest shows new bilateral infiltrates.
The formula for computing Cockcroft-Gault is given by CrCl = ((140 - age) * adjusted weight * (gender_coefficient)) / (serum creatinine * 72), where the gender_coefficient is 1 if male, and 0.85 if female. The serum creatinine concentration is in mg/dL.
The patient's gender is male, which means that the gender coefficient is 1.
The patient is 70 years old. 
The concentration of creatinine is 2.5 mg/dL. 
The formula for computing the patient's BMI is (weight)/(height * height), where weight is the patient's weight in kg and height is the patient's height in m.
The patient's height is 180.0 cm, which is 180.0 cm * 1 m / 100 cm = 1.8 m. The patient's weight is 90.0 kg. The patient's bmi is therefore 90.0 kg / (1.8 m * 1.8 m) = 27.778 kg/m^2.The patient's BMI is 27.8, indicating they are overweight/obese.
Because the patient is overweight/obese, we use the adjusted body weight formula to get the adjusted weight used for Cockroft-Gault Equation. Shown below is the computation for IBW (ideal body weight).
The patient's gender is Male.
The patient's height is 180.0 cm, which is 180.0 cm * 0.393701 in/cm = 70.866 in. 
For males, the ideal body weight (IBW) is calculated as follows:
IBW = 50 kg + 2.3 kg * (height (in inches) - 60)
Plugging in the values gives us 50 kg + 2.3 kg * (70.866 (in inches) - 60) = 74.992 kg.
Hence, the patient's IBW is 74.992 kg.Shown below is the computation for ABW (adjusted body weight).
To compute the ABW value, apply the following formula: ABW = IBW + 0.4 * (weight (in kg) - IBW (in kg)). ABW = 74.992 kg + 0.4 * (90.0 kg  - 74.992 kg) = 80.995 kg. The patient's adjusted body weight is 80.995 kg.

Using the Cockcroft-Gault equation:
CrCl = ((140 - age) * adjusted weight * gender_coefficient) / (serum creatinine * 72).
Plugging the patient's values gives us ((140 - 70) * 80.995 * 1) / (2.5 * 72) = 31.498 mL/min. Hence, the patient's creatinine clearance is 31.498 mL/min.