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Communications to the Editor |

# Does the Predicted Postoperative FEV1 Formula Reflect the Real Value?FREE TO VIEW

Erkan Yildirim
Author and Funding Information

Ankara Numune Education and Research Hospital Ankara, Turkey

Correspondence to: Erkan Yildiram, MD, Asagiövecler Mh, 79.Sk, 8/3 06460 Dikmen-Ankara, Turkey; e-mail: erseyda@yahoo.com

Chest. 2003;124(6):2409. doi:10.1378/chest.124.6.2409
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Published online

To the Editor:

I have just read the article by Beckles et al1 titled “The Physiologic Evaluation of Patients With Lung Cancer Being Considered for Resectional Surgery.” There was described a formula for calculating the percentage of predicted postoperative (ppo) FEV1 after lobectomy: ppoFEV1 = preoperative FEV1 × (No. of segments remaining/total No. of segments). For lobectomy, there is a strong correlation between the postoperative FEV1 expressed as percentage of predicted and the actual values when the calculation is made depending upon the number of segments to be removed at lobectomy. The calculation needs to be modified if any segments are obstructed2 :

where epo = estimated postoperative, and where a = the number of obstructed segments to be resected and b = the number of unobstructed segments to be resected, which can easily be determined by bronchoscopy.

In the first formula, the calculated ppo FEV1 values are always almost 150 to 250 mL less than the values calculated by the second formula upon the existence of obstructed segments. In both situations, the preoperative FEV1 values are the same. This condition is very important for the patients with borderline preoperative FEV1 values. The patients who are accepted inoperable according to the first formula may indeed be in the operable group. For example, a patient is being planned to undergo left upper lobectomy: a:2 and b:3. Preoperative FEV1 value is 1.6 L. According to the first formula, ppo FEV1 = 1.184 L; according to the second formula, epo FEV1 = 1.318 L. The difference is 134 mL. The obstructed segments to be resected do not have any contribution to the preoperative FEV1. So, only the unobstructed segments to be removed should be taken into account while calculating the epo FEV1. As a result, the first formula does not reflect the real value. In conclusion, the second formula should be used to calculate the percentage of ppo FEV1 in order to give the chance of operability to the patients with borderline respiratory functions.

## References

Beckles, MA, Spiro, SG, Colice, GL, et al (2003) The physiologic evaluation of patients with lung cancer being considered for resectional surgery.Chest123,1055-1145

British Thoracic Society and Society of Cardithoracic Surgeons of Great Britain and Ireland Working Pary. Guidelines on the selection of patients with lung cancer for surgery.Thorax2001;56,89-108. [CrossRef] [PubMed]

## References

Beckles, MA, Spiro, SG, Colice, GL, et al (2003) The physiologic evaluation of patients with lung cancer being considered for resectional surgery.Chest123,1055-1145

British Thoracic Society and Society of Cardithoracic Surgeons of Great Britain and Ireland Working Pary. Guidelines on the selection of patients with lung cancer for surgery.Thorax2001;56,89-108. [CrossRef] [PubMed]

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