Mechanical insufflation-exsufflation has been reported to decrease pneumonia rates by about 90% for patients with Duchenne muscular dystrophy now living into their 40s and 50s without tracheotomy tubes. It greatly reduces respiratory complications and hospitalization rates to less than one per 10 patient-years for advanced spinal muscular atrophy type 1, through 25–30 years of age. It is most successful from the point at which small children become able to cooperate with it, generally from 3 to 5 years of age. However, since the 1950s, successful use to extubate and decannulate ventilator “unweanable” patients with little to no measurable vital capacity without resorting to tracheostomy has always been at pressures of 50–60 cm H2O via oronasal interfaces and at 60–70 cm H2O via airway tubes when present. It must usually also be used in conjunction with up to continuous noninvasive positive pressure ventilatory support. Centers that use these effectively have eliminated need to resort to tracheotomies for people with muscular dystrophies and spinal muscular atrophies, including unmedicated patients with spinal muscular atrophy type 1. Barotrauma has been rare despite dependence on it and noninvasive ventilatory support. Despite this, noninvasive respiratory management continues to be widely underutilized.

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Mitropoulos G. et al.’s “Home use of mechanical insufflation-exsufflation (MIE) in adult patients in Western Switzerland,” a multicenter study on the subjective acceptability, impressions of efficacy, and use patterns of MIE, published in this issue, is an important step to increase interest in this vitally important intervention. MIE can literally spare patients, who are too weak to breathe or cough, from ever needing an invasive airway tube. However, MIE has been used since 1953 in centers in the USA but was approved for sale in Europe only in November 2004 [1, 2]. It was first used in Portugal and England, and presumably later in Switzerland, so an historical perspective is warranted.

Dr. Alvin Barach, along with Bickerman, Siegel, Gustav Beck, and engineer William Smith, developed MIE. They reported numerous studies on its efficacy and safety from 1953 through 1967 [2–5], always using it at 40 mm Hg via oronasal interfaces and mouthpieces with barotrauma being rare [5]. It went off the market because, in the absence of Iron Lungs, Danish physicians urged tracheotomies on post-poliomyelitis patients there [2–6], and the practice shifted to the USA to mobilize patients from Iron Lungs. No one reported using MIE via airway tubes until the 1980s [7].

With MIE already on the US market and always used at 40 mm Hg pressures to effectively “cough out” airway debris, the majority of iron lung users in centers in Los Angeles and New York used the ventilator tubing, meant to connect to tracheostomy tubes, to receive air via simple mouthpieces for up to continuous noninvasive ventilatory support (CNVS) since 1953 [8]. The original MIE device, when used at 40 mm Hg pressures, was so effective at preventing pneumonia [9] that many of the 257 patients who left iron lungs in 1957 for mouthpiece CNVS have never been hospitalized for any respiratory issues and continued to be CNVS dependent in 2017 and even today [10, 11].

The “Cof-flator™” was the original MIE device. People who had access to them, after 1967, shared them during intercurrent respiratory tract infections. Two patients published an open letter in 1988 demanding its re-manufacture, as shown in Figure 1. After being rejected by every ventilator manufacturer in the USA, I convinced Jack Emerson to re-manufacture it, and he gave us his prototype In-exsufflator™ 2 months later in November 1988. It was immediately put to use via airway tubes at pressures of 60–70 cm H2O to extubate and decannulate the tubes of ventilator-dependent patients to CNVS and MIE [12–14].

A patient using a 1967 Cof-flator™ (OEM Co., Hartford, Ct) and 2 patients’ plea to put mechanical in-exsufflation back on the market in 1988.

We first used nasal CNVS for patients with less than 200 mL of vital capacity (VC) in 1984 and for a multiple sclerosis patient with 100 mL of VC and no ventilator-free breathing ability in 1986 [15]. After her O2 saturation was normalized by using MIE via the tube in 1988, a 72-year-old spinal cord injured woman with 180 mL of VC was also extubated to nasal CNVS with her daughter then using MIE to clear her airways in the critical care unit to re-normalize every ambient air O2 desaturation below 95% [12]. In 1990, Alba and Bach described the oximetry feedback MIE protocol, using MIE for every ambient air O2 desaturation below 95% when awake to prevent pneumonia and to facilitate extubations and decannulations [15]. Because of MIE, we have had a 99% success rate at extubating over 300 ventilator unweanable patients in our pediatrics and adult critical care units, including pre-Nusinersen infants with severe spinal muscular atrophy type 1, who are today up to 29 years old with only residual eye movements and 0 mL of VC [11, 16, 17]. Since Mitropoulos et al. noted that many patients did not have oximeters, they are essentially being used “blindly” to avoid pneumonia during respiratory tract infections. Yet, oximeters can be had online for under $10 to guide MIE use.

The MIE meta-analyses and article reviews in the current literature are all without merit since they report the use of MIE at pressures of 40 cm H2O or less with arbitrary MIE time settings [18]. When the In-exsufflator™ came onto the US market in February 1993, I wrote review articles stating that it was identical to the Cof-flator™. However, the latter was calibrated in mm Hg but the former in cm H2O. I mistakenly noted that it should be used the same way but 40 mm Hg equals 54.1 cm H2O. Perhaps, at least in part as a result of my error, the CoughAssist™ has been used suboptimally ever since. Leith et al. [19] reported that effective coughs average 2.3 ± 0.3 L. This volume must be achieved quickly. In data, we have submitted on over 200 patients with ventilatory pump failure, all myopathy and lower motor neuron disease patients generated the greatest MIE-exsufflation flows (MIE-EF) at pressures of 50–60 cm H2O in and out. Even our 25- to 30-year-old spinal muscular atrophy type 1 patients with 0 mL of VC and only residual eye movements generate MIE-EF of 250–380 L/m.

When considering MIE use patterns, it should be noted that there are two potential reasons for using it. One is to augment cough flows when needed. The other is for passive lung volume recruitment (LVR) when “air stacking,” or active LVR, is not possible because of impaired glottis closure. Arbitrarily set pressures and regimens are unnecessary. For automatic cycling, insufflation times should be set to the time for full clinical chest expansion and exsufflation times set by time for full retraction, generally about 2.5 s in and 1.5 s out ±0.5 s. The higher the set pressures, the shorter the times. One of our extubated, unweanable CNVS users subsequently underwent scoliosis surgery in a New York City hospital where her effective 60 cm H2O settings were changed to 10 s in and 10 s out at 30 cm H2O pressure. Obviously, she could not survive at 3 breaths per minute and could not even get through the first 10 s phase of a single cycle.

Perhaps the many papers reviewed by Mitropoulos et al., including papers by Chatwin, used MIE at suboptimal pressures because their machines have not had expiratory flow measures. Low pressures are not always inappropriate for upper motor neuron disease patients with stridorous closure of the upper airways. Flows of 50–60 cm H2O create the highest flows and are virtually always, however, more effective for others. Requesting “high-quality studies,” in this day and age, implies control studies. However, breathing (mechanical ventilation) and coughing are vital bodily functions that cannot be matched to placebos. Anyone with bronchitis who cannot clear the airways will likely be dead in an hour or two. Comparing NVS or MIE to placebos is absurd, not to mention, unethical [20].

Except for patients with upper motor neuron diseases, whose MIE-EF may be greater at less than 50–60 cm H2O pressures via noninvasive interfaces, ventilatory pump failure patients with myopathic or lower motor neuron diseases tend to have the greatest MIE-EF flows and, therefore, the most effective cough flows, when MIE is used at 50–60 cm H2O pressures, as it was by using the original MIE device, the Cof-flatorTM, since the 1950s. Also, besides being useful for effective cough flows, it is useful for passive LVR for patients who cannot close their glottises for effective active LVR by “air stacking.” In this case, at least the insufflation pressure needs to be used at 50–60 or even 70 cm H2O about three times per day, as patients have been doing so since 1957 without untoward effects.

There are no ethical issues pertanent to these statements of simple facts.

The authors have no conflicts of interest to declare regarding this work.

There was no external funding.

J.B. and W.C. wrote the paper.

All the clinical facts presented in this paper are derived from the publications that make reference to them.

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