The feasibility, safety and optimization of multiple prolonged breath-holds for radiotherapy

Abstract

Background & purpose: Multiple, short breath-holds are now used in single radiotherapy treatment sessions. Here we investigated the feasibility and safety of multiple prolonged breath-holds in a single session. We measured how long is a second breath-hold if we prematurely terminate a single, prolonged breath-hold of >5 min either by using a single breath of oxygen (O 2), or by reintroducing preoxygenation and hypocapnia. We also investigated the feasibility and safety of undertaking 9 prolonged breath-holds in a row. Materials & methods: 30 healthy volunteers with no previous breath-holding experience were trained to perform single prolonged breath-holds safely. Results: Their mean single, prolonged breath-hold duration was 6.1 ± 0.3 se minutes (n = 30). In 18/18 subjects, premature termination (at 5.1 ± 0.2 min) with a single breath of 60% O 2 , enabled a 2nd safe breath-hold lasting 3.3 ± 0.2 min. In 18/18 subjects, premature termination at 5.3 ± 0.2 min) by reintroducing preoxygenation and hypocapnia, enabled a 2nd safe breath-hold lasting 5.8 ± 0.3 min. 17/17 subjects could safely perform 9 successive prolonged breath-holds, each terminated (at 4.3 ± 0.2 min) by reintroducing preoxygenation and hypocapnia for 3.1 ± 0.2 min. The 9th unconstrained breath-hold (mean of 6.0 ± 0.3 min) lasted as long as their single breath-hold. Conclusions: Multiple prolonged breath-holds are possible and safe. In a $19 min treatment session, it would therefore be possible to have $13 min for radiotherapy treatment (3 breath-holds) and $6 min for setup and recovery. In a 65 min session, it would be possible to have 41 min for radiotherapy and 25 min for setup and recovery.

The dosimetric benefit of in‐advance respiratory training for deep inspiration breath holding is realized during daily treatment in left breast radiotherapy: A comparative retrospective study of serial surface motion tracking

“…9,[14][15][16] While it has been recognized that a learning curve exists for patients to acquire the complex physical and cognitive skills to perform DIBH manoeuvres well, 17 only very few studies have explored alternative preparatorytraining approaches to boost patients' DIBH performance and tolerance. 13,[18][19][20][21] Logistically the timing of respiratory training can be expanded farther into the pre-radiation therapy phase, enabling earlier, preparatory and thereby more intensified DIBH training regimens that provide longer time for patients to practice and improve their DIBH skills. Results of these very few studies show promise that a strategy of early preparatory DIBH training and practice, implemented well in advance of the first DIBH performance at the simulation procedure, can measurably decrease procedure time spent in CT simulation, 13 lengthen the sustained DIBH 19,20 and broaden the range of breath-hold manoeuvres performed.…”

“…13,[18][19][20][21] Logistically the timing of respiratory training can be expanded farther into the pre-radiation therapy phase, enabling earlier, preparatory and thereby more intensified DIBH training regimens that provide longer time for patients to practice and improve their DIBH skills. Results of these very few studies show promise that a strategy of early preparatory DIBH training and practice, implemented well in advance of the first DIBH performance at the simulation procedure, can measurably decrease procedure time spent in CT simulation, 13 lengthen the sustained DIBH 19,20 and broaden the range of breath-hold manoeuvres performed. 21 Among these investigations, our previous comparison study was the first to demonstrate that cardiac dose can be further reduced by in-advance preparatory DIBH training and practice.…”

“…However, none of the early training studies 13,[18][19][20][21] evaluated whether the training-induced DIBH "stretch performance" was maintained during the entire treatment course. This is an important question to answer because, if DIBH performance erodes after the training regimen concludes, during the simulation-treatment start interval and/or during daily therapy, the gains from the improved DIBH would be reduced or lost.…”

Hypocapnia Alone Fails to Provoke Important Electrocardiogram Changes in Coronary Artery Diseased Patients

“…Non-invasive mechanical hyperventilation by facemask is a superior technique for inducing long and stable periods of severe hypocapnia. We have already established that this is easy for conscious, unmedicated and healthy subjects, and for patients with breast cancer (Parkes et al, 2016b), and produces long periods (up to 1 hr) of stable hypocapnia as severe as can safely be applied to patients (Cooper et al, 2003(Cooper et al, , 2004Rutherford et al, 2005;Sheppard et al, 2011;Parkes et al, 2019). Since mechanically induced hypocapnia is so simple, cheap and comfortable (for patients) to perform, it is potentially viable as a diagnostic modality for identifying patients with fixed coronary stenoses.…”

Defining short and prolonged breath-holds

“… 3 Furthermore, we have also developed techniques involving preoxygenation and hypocapnia to enable breast cancer patients to achieve safely “prolonged” breath-holds (>5 min), 4 and for healthy volunteers to perform multiple “prolonged” breath-holds (nine successive breath-holds of >4 min). 5 …”