To the Editor:
We read with much interest the editorial on protective ventilation by Hedenstierna and Edmark in the December issue of Anesthesiology.1 We agree with most of the ideas put forward. However, as thoracic anesthesiologists, we strongly believe in the importance, during one-lung ventilation, of low tidal volume based on ideal body weight.2,3
Many authors still recommend using the gender-specific Acute Respiratory Distress Syndrome Network (ARDSnet) formulas to calculate ideal body weight.4 Ideal body weight is computed in men as 50 + (0.91 × [height in centimeters − 152.4]) and in women as 45.5 + (0.91 × [height in centimeters − 152.4]). A simple alternative would be to compute ideal body weight as the weight corresponding to an ideal body mass index of 22 kg/m2. Ideal body weight is then simply calculated as 22 × ([the actual patient’s height in meters]^2) or by using body mass index charts available on our anesthesia cart.5 We chose 22 kg/m2 as the ideal body mass index after comparing the ideal body weight corresponding to body mass indices ranging from 20 to 25 to ideal body weight calculated from ADRSnet formulas. For example, a 1.75-m man would have an ideal body weight of 67 kg (22 × [1.75^2]) compared to 71 kg if using ARDSnet; a 1.60-m woman would have an ideal body weight of 56 kg (22 × [1.60^2]) compared to 52 kg if using ARDSnet.
The method we propose is simple and easy to remember. The same computation applies for both men and women and involves simple arithmetic.
The authors declare no competing interests.