Dear Editor,

The source of an idea that gives rise to a new discovery can be hard to pinpoint [1], but no difficulty arises in tracking the origin of the idea for including a 24-h rest arm in the above-cited randomized clinical trial.

The truncated left axis on the figure of Esteban and colleagues betrays their misunderstanding of the origin of that idea.

From 1982 onwards, Tobin had been undertaking research on the influence of the respiratory controller and respiratory muscles on mechanical ventilation and weaning. His laboratory presented this research annually (Table 1). Studies revealed a Janus-like relationship: too much ventilation risked atrophy, too little hindered recovery from fatigue.

Table 1 Chronology of events pertaining to 24-h rest arm in RCT of weaning techniques
Full size table

To determine optimal rest, Tobin’s laboratory investigated the pace of diaphragm recovery after incurring fatigue. In spring 1992, Laghi began experiments which showed the diaphragm needed 24 h to recover from fatigue. This work was submitted to ATS in November 1992. These facts belie Esteban and colleagues’ claim that the results “were probably obtained in the late 1993 or early 1994.”

In May 1991, Brochard’s group presented an RCT of three weaning techniques: T-tube trials repeated several times a day, SIMV, pressure support. Rest between each failed T-tube trial could be as brief as 1 h. When published, Brochard’s group did not mention that longer rest between T-tube trials might be beneficial.

When Tobin first met Esteban in August 1992, he already knew the diaphragm required 24 h of rest to recover from fatigue, and that T-tube trials in Brochard’s RCT entailed as little as 1 h rest. On the basis of years of researching the respiratory muscles, Tobin impressed upon Esteban the importance of a 24-h rest period in the design of an RCT of weaning techniques.

Three arms in the Spanish RCT were largely a copy of the Brochard design (Benito was an author on both), thus entailing zero novelty. Research lacking originality is, of course, otiose. The only novelty in the Spanish RCT was the idea for the fourth arm: patients who failed a T-tube trial would not undergo another until they had rested on assist-control ventilation for 24 h.

For unclear reasons, Esteban and colleagues believe that a sentence in the NEJM paper supports their claim to priority of ideas. That sentence simply provides a scientific base to the observation that a daily challenge, followed by 24 h of rest, enhances muscle plasticity. Deciphering the author of the sentence hardly requires expertise in stylometric forensics.

They note that the RCT paper does not reference the twitch paper. The reason is simple. The NEJM and JAP manuscripts moved in parallel, not in series (Table 1).

They preface their letter with lines from Lepera; more apt might be Tacitus, “Men are more ready to repay an injury than a benefit because gratitude is a burden and revenge a pleasure.”

The above chronology and litany of facts should be enough to allow each reader of ICM to form his or her own conclusion as to the source of the idea for including the 24-h rest arm in the RCT.