Reply to the Letter to the Editor: The “Cough Trick” Reduces Pain During Removal of Closed-suction Drains after Total Knee Arthroplasty: A Randomized Trial

To the Editor,

The authors thank Tiwari and colleagues for their thoughtful critique of our study [5], which included concerns about tethering or entrapment of drains [1-4].

In their letter, the authors noted that joint movements and muscular spasms while coughing might cause drain entrapment. When we designed the study protocol, we chose unsuccessful drain removal at bedside as one of the exclusion criteria because we were concerned about factors such as the unintentional suture of the drain tube, which might lead to the unsuccessful removal of the drain. Admittedly, we did not think about muscle spasms or joint movement while coughing as factors that might lead to the unsuccessful removal of the drain. Fortunately, all of the patients in our study experienced a successfully removal of the drain using this procedure. Additionally, in our practice experience, more than 300 patients who underwent TKA have had their drains removed successfully with this maneuver without any complications. We also performed this procedure while the patient lay supine with his or her knee in full extension. This position stabilizes the knee joint and relaxes the knee muscles. In our study, we did not observe any meaningful knee joint movement or vigorous contraction of the quadricep muscle while coughing, which might have made the drain removal unsuccessful. Still, we agree that applying this maneuver in other operations where it has never been employed before might require caution and awareness of potential associating complications.

Regarding our patient’s pain levels dropping below the baseline level by coughing, this is a question that many surgeons usually ask us in conferences. We believe that the pain level before drain removal and the pain during drain removal are two different things. The pain before drain removal refers to the baseline pain that the patient feels because of the overall treatment effect, whereas the pain during drain removal concerns the pain that the patient feels just at the moment when the drain is removed. Therefore, when reporting the pain score during drain removal, the patient might focus on only the pain (s)he feels while the drain is being removed—not the overall pain (s)he feels related to TKA. We realize that our data might be misunderstood as the “cough trick” being able to decrease baseline pain because, incidentally, the pain levels in the control group before and during drain removal were nearly the same; however, as explained above, we maintain that baseline pain and drain removal pain refer to two separate pain experiences. Nevertheless, we believe that if we had recorded the pain score again after the drain was removed, it would return to the baseline level.