S-Index assessment improves inspiratory muscle performance

S-Index stands for Strength-Index. It is one of the POWERbreathe K-Series’ test modes. Its purpose is to calculate inspiratory muscle strength based upon peak inspiratory flow.

Peak Inspiratory Flow (PIF)

We can evaluate improvements in inspiratory muscle strength by monitoring changes in a person’s peak inspiratory flow.

Peak Inspiratory Flow is a measure which reflects the ability of the inspiratory muscles (the muscles we use to breathe in) to contract rapidly and overcome the inherent resistance and elastance of the respiratory system.

Another of the K-Series’ test modes is the measurement of maximal inspiratory pressure (MIP). In fact, MIP is the most common measure in use for gauging inspiratory muscle strength. It is used as a diagnostic tool and an independent predictor of all-cause mortality.

Purpose of study

Currently, the most common test for assessing inspiratory muscle performance is the maximum ‘quasi-static’ inspiratory pressure (PImax).

However, the K-Series’ S-Index test has since become available for ‘dynamically’ evaluating the maximum inspiratory pressure.

In fact, it is suggested that the S-Index might be more appropriate for measuring inspiratory muscle performance than PImax.

Therefore, this study investigates this premise. It also assesses its reliability and whether an inspiratory muscle warm-up effects strength—index assessment.

Measurement validity of the K-Series

There are, in fact, current studies that have independently verified the measurement validity of the K-Series. Consequently, findings from these previous studies demonstrate its accuracy to measure dynamic inspiratory muscle pressure 1,2.

Therefore, this study feels that a proper assessment and the reliability of the S-Index should be addressed. In particular, it investigates the variability in response to repeated measurements. Furthermore, it evaluates whether an inspiratory muscle warm-up effects strength-index assessment. It is investigating whether using strength-index assessment improves clinical outcomes by reducing the bias effect.

Reliable values of the S-Index

What this study demonstrates is that at least 8 inspiratory manoeuvres are necessary to reach maximum and reliable values of the S-Index. Moreover, it also shows that specific inspiratory muscle warm-up could improve inspiratory muscle performance.

The authors believe this to be the first study to evaluate S-Index reliability in healthy subjects. Furthermore, they believe it to be the first study to investigate the effect of inspiratory warm-up in strength-index assessment.

In conclusion, inspiratory muscle warm-up should be used for detecting the true maximum values of the S-Index to evaluate the performance of inspiratory muscles for any intervention.

Assessment of Maximum Dynamic Inspiratory Pressure >

References

  1. Measurement validity of an electronic inspiratory loading device during a loaded breathing task in patients with COPD
  2. Repeated-Sprint Cycling Does Not Induce Respiratory Muscle Fatigue in Active Adults: Measurements from The POWERbreathe Inspiratory Muscle Trainer 

Influence Of IMT On Changes In Sleep Architecture In Older Adult

“This project aims to investigate the influence of inspiratory muscle training through the Threshold® on sleep disorders and involved the participation of 38 older adult volunteers of both genders with sleep disorders.”

Conclusion:

“Results suggested that inspiratory muscle training can be a good help in the treatment of sleep-related breathing disorders.”

Read Influence of Inspiratory Muscle Training on Changes in Sleep Architecture in Older Adult – Epidoso Projects >

A New Device For IMT In Patients With Tracheostomy Tube In ICU: A Randomized Trial

The objective of this randomised controlled trial was to compare the inspiratory muscle strength between two groups of tracheostomy patients: Inspiratory Muscle Training with POWERbreathe and breathing through a humidified t-piece (T-tune).

Conclusion:

“The Inspiratory Muscle Training with POWERbreathe in tracheostomy patients promotes increased muscle strength.”

Read A new device for inspiratory muscle training in patients with tracheostomy tube in ICU: A randomized trial >

IMT In Mechanical Ventilation: Suitable Protocols And Endpoints, The Key To Clear Results – A Critical Review

“Forty percent of the overall time spent in the ICU was reported to be devoted to weaning of MV. The major cause of weaning failure is the imbalance between the imposed load on the respiratory system and its capacity to overcome that.”

Conclusion:

“Inspiratory Muscle Training on mechanically ventilated patients seems to be a promissory treatment despite controversial results. Randomised Controlled Trials should be carried out to verify the efficacy of the high intensity training during a suitable period of training using electronic kinetic devices in mechanically ventilated patients.”

Read Inspiratory muscle training in mechanical ventilation: suitable protocols and endpoints, the key to clear results – a critical review >

IMT in mechanical ventilation: suitable protocols and endpoints

RESEARCH:

Inspiratory muscle training in mechanical ventilation: suitable protocols and endpoints, the key to clear results – a critical review

Silva, Paulo Eugênio

This research from Faculdade de Educação Física, Universidade de Brasília looked into whether Inspiratory Muscle Training (IMT) led to a shorter duration of mechanical ventilation, improved weaning success, or improved survival.

The purpose of this critical review was to determine:

1. What is the ideal prescription of IMT for patients on MV?
2. What is the best time to measure treatment effect?
3. Which kind of device should be used to IMT?
4. What are the best endpoints to evaluate the effects of IMT on the process of discontinuing from MV?

Which kind of device should be used to IMT? POWERbreathe K-Series.

“The biggest challenge in the training of mechanically ventilated patients is the use of conventional devices to impose loads on the respiratory muscles. When training starts, the patient must be disconnected from the ventilator and the respiratory monitoring is lost.”

“A new class of device is now available that is possible to monitor respiratory variables during the training. One example of this is the POWERbreathe K-Series (POWERbreathe-HaB UK) an electronic K-device with feedback software that helps professionals to understand what is happening with patients during their training. This device provides automatically processed information on external inspiratory work. Moreover, power and breathing patterns during loaded breathing tasks is shown, thus the onset of fatigue can be detected earlier.”

“POWERbreathe K-Series was externally evaluated by Belgian researchers and they concluded that the K-Series technology provides automatically processed and valid estimates of physical units of energy during loaded breathing tasks. Recently, de Souza et al. published a case report showing good results using the same technology to train a prolonged mechanically ventilated patient.”

“Another great advantage of this kind of technology is the capacity of load adjustment (1 cmH2O per 1 cmH2O) reaching 3 to 200 cmH2O. Beyond that, the device can adjust the load dynamically, imposing higher load at the beginning of inspirations and lower load close to vital capacity. Thus, a greater range of motion can be reached improving the effectiveness of the training.”

CONCLUSION:

“This review demonstrated the necessity of new RCTs despite of some well designed RCTs have already been published. Many evidences point out that a high intensity training with loads ≥ 50% of MIP in 5 to 6 sets, aiming to reach thirty breathes, one or twice a day, seven days per week is a suitable protocol to improve performance on mechanical ventilation. Patients must be trained at least for two weeks in order to IMT promotes clinically significant effects. It is possible, that outcomes such as the onset of weaning process, duration and success on the weaning, have higher correlation with IMT.” “In conclusion, IMT on mechanically ventilated patients seems to be a promissory treatment despite controversial results. RCTs should be carried out to verify the efficacy of the high intensity training during a suitable period of training using electronic kinetic devices in mechanically ventilated patients.”

Read Inspiratory muscle training in mechanical ventilation: suitable protocols and endpoints, the key to clear results – a critical review