Diaphragm pacing improves respiratory mechanics in acute cervical spinal cord injury

[S3 Guideline: Treating Chronic Respiratory Failure with Non-invasive Ventilation]

The S3 guideline on non-invasive ventilation as a treatment for chronic respiratory failure was published on the website of the Association of the Scientific Medical Societies in Germany (AWMF) in July 2024. It offers comprehensive recommendations for the treatment of chronic respiratory failure in various underlying conditions, such as COPD, thoraco-restrictive diseases, obesity-hypoventilation syndrome, and neuromuscular diseases. An important innovation is the separation of the previous S2k guideline dating back to 2017, which included both invasive and non-invasive ventilation therapy. Due to increased scientific evidence and a significant rise in the number of affected patients, these distinct forms of therapy are now addressed separately in two different guidelines.The aim of the guideline is to improve the treatment of patients with chronic respiratory insufficiency using non-invasive ventilation and to make the indications and therapy recommendations accessible to all involved in the treatment process. It is based on the latest scientific evidence and replaces the previous guideline. This revised guideline provides detailed recommendations on the application of non-invasive ventilation, ventilation settings, and the subsequent follow-up of treatment.In addition to the updated evidence, important new features of this S3 guideline include new recommendations on patient care and numerous detailed treatment pathways that make the guideline more user-friendly. Furthermore, a completely revised section is dedicated to ethical issues and offers recommendations for end-of-life care. This guideline is an important tool for physicians and other healthcare professionals to optimize the care of patients with chronic respiratory failure. This version of the guideline is valid for three years, until July 2027.

Diaphragm pacing compared with mechanical ventilation in patients with chronic respiratory failure caused by diaphragmatic dysfunction: a systematic review and meta-analysis

BACKGROUND

The effectiveness of diaphragmatic electrical stimulation (DES) compared to mechanical ventilation (MV) in improving clinical outcomes such as quality-of-life (QOL) and hospital stay remains inconsistent.

METHODS

We conducted a systematic review and meta-analysis by searching PubMed, Scopus, Google Scholar, LILACS, and IEEE Xplore. We included comparative studies (randomized controlled trials and observational studies) of DES administered via the phrenic nerve or intramuscular electrodes, compared with MV in adults with diaphragmatic paralysis or paresis. Two authors independently extracted data and assessed bias, with discrepancies resolved by a senior author. Results were pooled using the inverse variance method.

RESULTS

Out of 1,290 articles, nine were included in the systematic review, totaling 852 subjects. In spinal cord injury (SCI), one study reported lower mortality with DES, while three found no difference compared to MV. In these patients, DES was associated with shorter hospital stay, similar QOL, and heterogeneous results on respiratory infections. In amyotrophic lateral sclerosis (ALS), DES was associated with higher mortality and similar QOL compared to MV. Most SCI studies had a serious risk of bias.

CONCLUSION

DES shows potential in reducing hospital stay and respiratory infections in SCI but is associated with higher mortality in ALS.

Randomized study of temporary diaphragm pacing for enhanced recovery after surgery in cardiac surgery patients at risk of prolonged mechanical ventilation

Objective

Prolonged mechanical ventilation after cardiac surgery significantly increases morbidity and mortality. The aim of this study is to establish the role of diaphragmatic pacing to decrease mechanical ventilation burden in high-risk patients undergoing cardiac surgery.

Methods

This is a prospective, randomized trial of temporary diaphragmatic pacing electrode use in patients undergoing cardiac surgery (NCT04899856). Prognostic enrichment strategy was used to identify patients at higher risk of prolonged mechanical ventilation by having inclusion criteria of prior open cardiac surgery, left ventricular ejection fraction less than 30%, history of stroke, intra-aortic balloon pump, or history of chronic obstructive pulmonary disease. Two electrodes were placed in each hemidiaphragm intraoperatively. On arrival to the intensive care unit, patients were randomized to immediate diaphragmatic pacing or standard of care.

Results

Forty patients received implants, with 19 in the treatment group and 21 in the standard of care group. Only 1 patient in the treatment group was on mechanical ventilation at 24 hours versus 4 patients in the standard of care group, resulting in a relative risk reduction of 71% being on mechanical ventilation at 24 hours postoperatively. Predictive enrichment strategy was used to identify patients most likely to respond to therapy of diaphragmatic pacing. In this analysis, median time on mechanical ventilation was 17.7 hours (interquartile range, 8.3-23.4) for the 15 patients in the standard of care group and 9.4 hours (interquartile range, 7.14-12.5) for the 13 patients in the treatment group, for an improvement of 8 hours with diaphragm pacing (P < .05).

Conclusions

Temporary diaphragmatic pacing improved weaning from mechanical ventilation by 8 hours with a significant reduction of prolonged mechanical ventilation. Multicenter randomized trials confirming diaphragmatic pacing as an Enhanced Recovery After Surgery tool to decrease mechanical ventilation may reduce length of stay, postoperative infections, and additive costs.

An Implantable Self-Driven Diaphragm Pacing System Based on a Microvibration Triboelectric Nanogenerator for Phrenic Nerve Stimulation

Spinal cord injury poses considerable challenges, particularly in diaphragm paralysis. To address limitations in existing diaphragm pacing technologies, we report an implantable, self-driven diaphragm pacing system based on a microvibration triboelectric nanogenerator (MV-TENG). Leveraging the efficient MV-TENG, the system harvests micromechanical energy and converts this energy into pulses for phrenic nerve stimulation. In vitro tests confirm a stable MV-TENG output, while subcutaneous implantation of the device in rats results in a constant amplitude over 4 weeks with remarkable energy-harvesting efficacy. The system effectively induces diaphragmatic motor-evoked potentials, triggering contractions of the diaphragm. This proof-of-concept system has potential clinical applications in implantable phrenic nerve stimulation, presenting a novel strategy for advancing next-generation diaphragm pacing devices.

Diaphragm pacing and independent breathing in individuals with severe Pompe disease

Introduction

Pompe disease is an inherited disease characterized by a deficit in acid-α-glucosidase (GAA), an enzyme which degrades lysosomal glycogen. The phrenic-diaphragm motor system is affected preferentially, and respiratory failure often occurs despite GAA enzyme replacement therapy. We hypothesized that the continued use of diaphragm pacing (DP) might improve ventilator-dependent subjects' respiratory outcomes and increase ventilator-free time tolerance.

Methods

Six patients (3 pediatric) underwent clinical DP implantation and started diaphragm conditioning, which involved progressively longer periods of daily, low intensity stimulation. Longitudinal respiratory breathing pattern, diaphragm electromyography, and pulmonary function tests were completed when possible, to assess feasibility of use, as well as diaphragm and ventilatory responses to conditioning.

Results

All subjects were eventually able to undergo full-time conditioning via DP and increase their maximal tolerated time off-ventilator, when compared to pre-implant function. Over time, 3 of 6 subjects also demonstrated increased or stable minute ventilation throughout the day, without positive-pressure ventilation assistance.

Discussion

Respiratory insufficiency is one of the main causes of death in patients with Pompe disease. Our results indicate that DP in Pompe disease was feasible, led to few adverse events and stabilized breathing for up to 7 years.

Observational study of early diaphragm pacing in cervical spinal cord injured patients to decrease mechanical ventilation during the COVID-19 pandemic

BACKGROUND

Decreasing the burden of mechanical ventilation for spinal cord injuries was never more relevant than during the COVID-19 pandemic. Data have shown diaphragm pacing can replace mechanical ventilation, decrease wean times, improve respiratory mechanics, and decrease hospital costs for patients with spinal cord injuries. This is the largest report of diaphragm pacing during the pandemic.

METHODS

This is a retrospective analysis of prospective Institutional Review Board approved databases of nonrandomized interventional experience at a single institution. Subgroup analysis limited to traumatic cervical spinal cord injuries that were implanted laparoscopically with diaphragm electrodes within 30 days of injury.

RESULTS

For the study group of early implanted traumatic cervical spinal cord injuries, 13 subjects were identified from a database of 197 diaphragm pacing implantations from January 1, 2020, to December 31, 2022, for all indications. All subjects were male with an average age of 49.3 years (range, 17-70). Injury mechanisms included falls (6), motor vehicle accident (4), gunshot wound (2), and diving (1). Time from injury to diaphragm pacing averaged 11 days (range, 3-22). Two patients are deceased and neither weaned from mechanical ventilation. Nine of the remaining 11 patients weaned from mechanical ventilation. Four patients never had a tracheostomy and 3 additional patients had tracheostomy decannulation. Three of these high-risk pulmonary compromised patients survived COVID-19 infections utilizing diaphragm pacing.

CONCLUSION

Diaphragm pacing successfully weaned from mechanical ventilation 82% of patients surviving past 90 days. Forty-four percent of this group never underwent a tracheostomy. Only 22% of the weaned group required long term tracheostomies. Early diaphragm pacing for spinal cord injuries decreases mechanical ventilation usage and tracheostomy need which allows for earlier placement for rehabilitation.

The effects of external diaphragmatic pacing on diaphragm function and weaning outcomes of critically ill patients with mechanical ventilation: a prospective randomized study

BACKGROUND

Diaphragmatic pacing can improve diaphragm function, which is beneficial for the prognosis of patients treated with prolonged mechanical ventilation (MV). While most previous studies have focused on the role of implanted diaphragm pacing (IDP), our study is the first to examine the effects of external diaphragmatic pacing (EDP) in mechanically ventilated patients. Specifically, the effect of EDP on diaphragm function, the success rate of weaning, the duration of MV (DMV), and the intensive care unit (ICU) length of stay (ILOS) were assessed.

METHODS

From September 2019 to December 2020, a total of 51 mechanically ventilated patients in the ICU of the Sun Yat-sen Memorial Hospital, Sun Yat-sen University were enrolled and randomly divided into an EDP group of 27 patients and a control group of 24 patients. The control group received routine treatment, and the EDP group received EDP treatment in addition to routine treatment. The diaphragm excursion (DE), diaphragm thickening fraction (DTF), DMV, ILOS, and average survival time were recorded to evaluate efficacy.

RESULTS

Patients treated with EDP had increased DE [exp(B) =1.86, 95% CI: 1.39 to 2.50, P<0.001] and DTF [exp(B) =1.35, 95% CI: 1.05 to 1.76, P=0.022], shortened weaning time (P=0.026) and prolonged average survival time (P<0.001) compared to patients who did not receive EDP therapy. Especially in cases with difficult weaning, the improvement of DE and DTF in the EDP treatment group was more obvious than that in the control group (P=0.013 and P=0.032). Moreover, the DTF upon attempted spontaneous breathing trial (SBT) was negatively correlated with the fraction of inspired oxygen (FiO2) [r=-0.54; 95% confidence interval (CI): -0.77 to -0.19; P=0.004], the arterial partial pressure of oxygen (PaO2) (r=-0.58; 95% CI: -0.79 to -0.25; P=0.001), the PaO2/FiO2 ratio (r=-0.52; 95% CI: -0.75 to -0.16; P=0.006), and the serum lactate concentration (Lac) (r=-0.39; 95% CI: -0.68 to 0.003; P=0.046).

CONCLUSIONS

EDP treatment can effectively reduce the DMV and prolong the average survival time of mechanically ventilated patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR1900024096.

Diaphragm Pacing and a Model for Respiratory Rehabilitation After Spinal Cord Injury

BACKGROUND AND PURPOSE

Cervical spinal cord injury (CSCI) can cause severe respiratory impairment. Although mechanical ventilation (MV) is a lifesaving standard of care for these patients, it is associated with diaphragm atrophy and dysfunction. Diaphragm pacing (DP) is a strategy now used acutely to promote MV weaning and to combat the associated negative effects. Initial reports indicate that DP also may promote neuromuscular plasticity and lead to improvements in spontaneous diaphragm activation and respiratory function. These outcomes suggest the need for reevaluation of respiratory rehabilitation for patients with CSCI using DP and consideration of new rehabilitation models for these patients and their unique care needs.

SUMMARY OF KEY POINTS

This article discusses the rationale for consideration of DP as a rehabilitative strategy, particularly when used in combination with established respiratory interventions. In addition, a model of respiratory rehabilitation and recovery (RRR) is presented, providing a framework for rehabilitation and consideration of DP as an adjuvant rehabilitation approach. The model promotes goals such as respiratory recovery and independence, and lifelong respiratory health, via interdisciplinary care, respiratory training, quantitative measurement, and use of adjuvant strategies such as DP. Application of the model is demonstrated through a description of an inpatient rehabilitation program that applies model components to patients with CSCI who require DP.

RECOMMENDATIONS FOR CLINICAL PRACTICE

As DP use increases for patients with acute CSCI, so does the need and opportunity to advance rehabilitation approaches for these patients. This perspective article is a critical step in addressing this need and motivating the advancement of rehabilitation strategies for CSCI patients. (See Video Abstract, Supplemental Digital Content, available at: http://links.lww.com/JNPT/A348).

Spinal cord injury level and Phrenic Nerve Conduction Studies do not predict diaphragm pacing success or failure- all patients should undergo diagnostic laparoscopy

BACKGROUND

Diaphragm Pacing(DP) demonstrates benefits over mechanical ventilation(MV) for spinal cord injured(SCI) patients. The hypothesis of this report is that phrenic nerve conduction study(PNCS) results cannot differentiate success or failure in selection of patients for DP. Direct surgical evaluation of the diaphragm should be performed.

METHODS

Observational report of prospective databases of patients undergoing laparoscopic evaluation of their diaphragms to assess for ability to stimulate to cause contraction for ventilation.

RESULTS

In 50 SCI patients who could not be weaned from MV, PNCS results showed latencies in stimulated patients (n = 44) and non-stimulated(n = 6) overlapped (7.8 ± 2.5 ms vs 9.4 ± 2.8 ms) and the null hypothesis cannot be rejected (p-value>0.05). Amplitudes overlapped (0.4 ± 0.2 mV vs 0.2 ± 0.2 mV) and the null hypotheses cannot be rejected (P-value >0.05). In 125 non SCI patients with diaphragm paralysis, there were 78(62.4%) with false negative PNCS.

CONCLUSION

PNCS are inadequate pre-operative studies. Direct laparoscopic evaluation should be offered for all SCI patients to receive the benefit of DP.