Use of diaphragm pacing in the management of acute cervical spinal cord injury

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.

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.

Diaphragm Pacing: A Safety, Appropriateness, Financial Neutrality, and Efficacy Analysis of Treating Chronic Respiratory Insufficiency

OBJECTIVES

This study aimed to evaluate the safety and applicability of treating chronic respiratory insufficiency with diaphragm pacing relative to mechanical ventilation.

MATERIALS AND METHODS

A literature review and analysis were conducted using the safety, appropriateness, financial neutrality, and efficacy principles.

RESULTS

Although mechanical ventilation is clearly indicated in acute respiratory failure, diaphragm pacing improves life expectancy, increases quality of life, and reduces complications in patients with chronic respiratory insufficiency.

CONCLUSION

Diaphragm pacing should be given more consideration in appropriately selected patients with chronic respiratory insufficiency.

Diaphragm Pacing in Spinal Cord Injury Can Significantly Decrease Mechanical Ventilation in Multicenter Prospective Evaluation

BACKGROUND

Cervical spinal cord injury (SCI) can lead to dependence on mechanical ventilation (MV) with significant morbidity and mortality. The diaphragm pacing system (DPS) was developed as an alternative to MV.

METHODS

We conducted a prospective single arm study of DPS in MV dependent patients with high SCI and intact phrenic nerves. Following device acclimation, pacing effectiveness to provide ventilation was evaluated. The primary endpoint was the number who could use DPS to breathe for four continuous hours without MV. Secondary endpoints included the number of patients that could use DPS 24 hours/day free of MV and the ability of DPS to maintain clinically acceptable tidal volume (Vt). In addition, we conducted a meta-analysis that included the prospective study along with data from four recently published studies to evaluate DPS hourly use.

RESULTS

Fifty-three patients were implanted in the prospective study. Most were male (77.4%) with a median time from injury to treatment of 28.3 (IQR 12.1, 83.3) months. Four- and 24-hour use occurred in 96.2% (95%CI - 87.0%, 99.5%) and 58.5% (95% CI - 44.1%, 74.9%), respectively. Four and 24-hour results in the meta-analysis cohort (n=196) exhibited similar results 92.2% (95% CI - 82.6%,96.7%) and 52.7% (95% CI - 36.2%,68.6%) using DPS for four and 24 hours, respectively. DPS use significantly exceeded the calculated basal tidal volume requirements by a mean of 48.4% (95% CI - 37.0, 59.9%; p<0.001).

CONCLUSIONS

This study demonstrates that in most ventilator-dependent patients, diaphragm pacing can effectively supplement or completely replace the need for MV and support basal metabolic requirements.

Diaphragm Pacing in Patients with Spinal Cord Injury: A European Experience

BACKGROUND

Patients with high spinal cord injury (SCI) are unable to breathe on their own and require mechanical ventilation (MV). The long-term use of MV is associated with increased morbidity and mortality. In patients with intact phrenic nerve function, patients can be partially or completely removed from MV by directly stimulating the diaphragm motor points with a diaphragm pacing system (DPS).

OBJECTIVES

We describe our multicenter European experience using DPS in SCI patients who required MV.

METHODS

We conducted a retrospective study of patients who were evaluated for the implantation of DPS. Patients evaluated for DPS who met the prospectively defined criteria of being at least 1 year of age, and having cervical injury resulting in a complete or partial dependency on MV were included. Patients who received DPS implants were followed for up to 1 year for device usage and safety.

RESULTS

Across 3 centers, 47 patients with high SCI were evaluated for DPS, and 34 were implanted. Twenty-one patients had 12 months of follow-up data with a median DPS use of 15 h/day (interquartile range 4, 24). Eight patients (38.1%) achieved complete MV weaning using DPS 24 h/day. Two DPS-related complications were surgical device revision and a wire eruption. No other major complications were associated with DPS use.

CONCLUSIONS

Diaphragm pacing represents an attractive alternative stand-alone treatment or adjunctive therapy compared to MV in patients with high SCI. After a period of acclimation, the patients were able to reduce the daily use of MV, and many could be completely removed from MV.

Diaphragm pacing improves respiratory mechanics in acute cervical spinal cord injury

BACKGROUND

Cervical spinal cord injury (CSCI) is devastating with ventilator-associated pneumonia being a main driver of morbidity and mortality. Laparoscopic diaphragm pacing implantation (DPS) has been used for earlier liberation from mechanical ventilation. We hypothesized that DPS would improve respiratory mechanics and facilitate liberation.

METHODS

We performed a retrospective review of acute CSCI patients between January 2005 and May 2017. Routine demographics were collected. Patients underwent propensity score matching based on age, Injury Severity Score, ventilator days, hospital length of stay, and need for tracheostomy. Patients with complete respiratory mechanics data were analyzed and compared. Those who did not have DPS (NO DPS) had spontaneous tidal volume (Vt) recorded at time of intensive care unit admission, at day 7, and at day 14, and patients who had DPS had spontaneous Vt recorded before and after DPS. Time to ventilator liberation and changes in size of spontaneous Vt for patients while on the ventilator were analyzed. Bivariate and multivariate logistic and linear regression statistics were performed using STATA v10.

RESULTS

Between July 2011 and May 2017, 37 patients that had DPS were matched to 34 who did not (NO DPS). Following DPS, there was a statistically significant increase in spontaneous Vt compared with NO DPS (+88 mL vs. -13 mL; 95% confidence interval, 46-131 mL vs. -78 to 51 mL, respectively; p = 0.004). Median time to liberation after DPS was significantly shorter (10 days vs. 29 days; 95% CI, 6.5-13.6 days vs. 23.1-35.3 days; p < 0.001). Liberation prior to hospital discharge was not different between the two groups. The DPS placement was found to be associated with a statistically significant decrease in days to liberation and an increase in spontaneous Vt in multivariate linear regression models.

CONCLUSION

The DPS implantation in acute CSCI patients produces significant improvements in spontaneous Vt and reduces time to liberation from mechanical ventilation. Prospective comparative studies are needed to define the clinical benefits and potential cost savings of DPS implantation.

LEVEL OF EVIDENCE

Therapeutic IV.

An observation of the clinical efficacy of combining Riluzole with mannitol and hyperbaric oxygen in treating acute spinal cord injury

Objective:

To examine the clinical efficacy of combining Riluzole with mannitol and hyperbaric oxygen therapy in treating thoracolumbar vertebral fracture-induced acute spinal cord injury (ASCI).

Methods:

From June 2015 to May 2018, 80 patients with thoracolumbar fractures and ASCI who were treated at Baoding First Central Hospital were selected. All patients underwent posterior laminectomy and screw fixation, and they were randomly divided into two groups using a random number table method. The control group received conventional postoperative treatment, while the experimental group was treated with riluzole combined with mannitol and hyperbaric oxygen on the basis of conventional treatment. The recovery of nerve function which included motor function and sensory function, and the changes of serum IL-6, CRP, BDNF, BFGF and other factors before treatment and four weeks after treatment of the two groups of patients were observed and evaluated.

Results:

After treatment, the motor function scores and sensory function scores of the two groups of patients were improved compared with those before treatment (p<0.05). Compared with the control group, the experimental group improved significantly, and the difference was statistically significant (p<0.05). The levels of IL-6, BDNF and NFGF in the experimental group were significantly lower than those in the control group (p<0.05).

Conclusions:

For patients with thoracolumbar fractures and ASCI undergoing laminar decompression and fixation, the comprehensive treatment plan of riluzole combined with mannitol and hyperbaric oxygen has certain advantages. Compared with the conventional therapy, it may significantly improve the movement and sensory functions of patients, relieve the inflammatory response of spinal cord, and promote recovery from the injury.

Diaphragm pacing decreases hospital charges for patients with acute cervical spinal cord injury

Background

Cervical spinal cord injury (CSCI) is devastating and costly. Previous research has demonstrated that diaphragm pacing (DPS) is safe and improves respiratory mechanics. This may decrease hospital stays, vent days, and costs. We hypothesized DPS implantation would facilitate liberation from ventilation and would impact hospital charges.

Methods

We performed a retrospective review of patients with acute CSCI between January 2005 and May 2017. Routine demographics were collected. Patients underwent propensity matching based on age, injury severity score, ventilator days, hospital length of stay, and need for tracheostomy. We then adjusted total hospital charges by year using US Bureau of Labor Statistics annual adjusted Medical Care Prices. Bivariate and multivariate linear regression statistics were performed using STATA V.15.

Results

Between July 2011 and May 2017, all patients with acute CSCI were evaluated for DPS implantation. 40 patients who had laparoscopic DPS implantation (DPS) were matched to 61 who did not (NO DPS). Following DPS implantation, there was a statistically significant increase in spontaneous Vt compared with NO DPS (+88 mL vs −13 mL; 95% CI 46 to 131 vs −78 to 51 mL, respectively; p=0.004). Median time to liberation after DPS was significantly shorter (10 vs 29 days; 95% CI 6.5 to 13.6 vs 23.1 to 35.3 days; p<0.001). Adjusted hospital charges were significantly lower for DPS on multivariate linear regression models controlling for year of injury, sex, race, injury severity, and age (p=0.003).

Discussion

DPS implantation in patients with acute CSCI produces significant improvements in spontaneous Vt and reduces time to liberation, which translated into reduced hospital charges on a risk-adjusted, inflation-adjusted model. DPS implantation for patients with acute CSCI should be considered.

Level of evidence

Level III.

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.

Early use of an implantable diaphragm pacing stimulator for a child with severe acute flaccid myelitis-a case report

Introduction

Acute Flaccid Myelitis (AFM) is a recently recognized, polio-like illness of children that can be functionally devastating. Severe cases can lead to ventilatory failure. Incomplete phrenic nerve injuries in other populations has been shown to respond to diaphragmatic stimulation. We therefore proposed an early assessment for incomplete denervation by laparoscopic direct stimulation of the diaphragm and placement of a diaphragmatic pacing system to enhance diaphragm function.

Case presentation

A 3 year-old girl presented with AFM with clinically and electrodiagnostically severe involvement of all four limbs and muscles of respiration. Direct stimulation of the diaphragm demonstrated contraction and a diaphragmatic stimulator was placed at 3 weeks post presentation. The patient was immediately able to tolerate short bouts of reduced ventilation settings. Electromyography via the pacing wires demonstrated intact motor units consistent with partial denervation/reinnervation in the left hemidiaphragm, and no motor units in the right hemidiaphragm. At three months, she tolerated 6 h of pacing on pressure support setting. At 5 months she demonstrated larger tidal volumes with active pacing than without.

Discussion

In our experience, AFM patients who require chronic ventilator support are rarely able to be weaned. Despite clinical and surface electrodiagnostic evidence of complete phrenic nerve involvement, the patient's diaphragm responded to direct stimulation. The patient preferred pacing over non-pacing times and showed improved ventilatory ability with pacing as opposed to without, though remains ventilator-dependent. These findings support augmentation of diaphragm function and possible enhanced recovery of spontaneous function.