Taking the laparoscope to the laboratory for ventilatory research

Area of Science:

• Biomedical Engineering
• Surgical Innovation
• Respiratory Physiology

Background:

• Phrenic nerve stimulation for chronic ventilatory support is limited by risks of permanent nerve injury.
• Previous research indicated safety and efficacy of direct muscle stimulation for extended durations.

Purpose of the Study:

• To evaluate the safety and feasibility of laparoscopic diaphragm pacing electrode implantation in canines.
• To establish a foundation for clinical trials of diaphragm pacing as a ventilatory support method.

Main Methods:

• A laparoscopic technique was employed for direct implantation of diaphragm pacing electrodes in 16 canines (10 acute, 6 chronic).
• Electrodes were inserted via 19-gauge needles under laparoscopic visualization into both hemidiaphragms.
• Evaluated parameters included tidal volume, transdiaphragmatic pressure, arterial blood gas, impedance, cardiac activation, and histology.

Main Results:

• Maximal evoked tidal volume reached approximately 400% of resting tidal volume in both acute and chronic models.
• Chronic pacing was sustained for up to 179 days with 24-hour per day stimulation.
• No instances of cardiac ectopy were observed during the study.
• Histological examination confirmed the safety of electrode placement sites.

Conclusions:

• Laparoscopic diaphragm pacing is a safe and feasible method for direct muscular activation, offering a viable alternative for chronic ventilatory support.
• This technique minimizes risks associated with phrenic nerve stimulation.
• The study supports progression to human clinical trials and suggests broader applications for laparoscopic electrode placement.