Complete cervical spinal cord injury (SCI) usually requires ventilator support. As an alternative to mechanical ventilation, stimulation of the phrenic nerve with electrodes implanted in the diaphragm is gaining acceptance. There is a need, however, to improve diaphragm stimulation and to add abdominal and upper thorax intercostal muscle stimulation for improved respiration and cough. We will test a new electrode for these applications: the PermalocTM bipolar multi-contact (P-BMC) electrode (Synapse Biomedical Inc). Respiratory responses with the new electrode will also be enhanced by using a high current respiratory stimulator and a biphasic stimulating wave form. One group of 12 acute dogs will be studied during this 1-YR investigation. Respiratory pacing studies following anesthesia will be conducted during periods of respiratory apnea following hyperventilation. Protocols will follow the order of the Aims of the study in each animal. Tracheal pressure will be the primary measure whereas airway flow will also be a primary measure. For cough and 20 min pacing tests airflow will be the primary measure. Additional respiratory measures will include esophageal and abdominal pressures. The recording of pneumobelts will provide a qualitative measure of upper-chest and abdominal muscle expansion and contractions to be recorded during airflow studies. Muscle contractile responses to stimulation will also be rated based on observation and palpation. Stimulation testing methods will include duplicate tests with random order assignment. All data will be presented as Mean + SEM. Statistical analysis will be done by ANOVA with post hoc comparisons made using the Student-Neuman-Keuls test. Results of this study are expected to contribute to technology transfer of the new electrode for cervical-level SCI patients.
Respiratory problems continue to be a primary concern for individuals with upper-level cervical spinal cord injury (SCI) with mortality most often attributed to pneumonia and usually requires ventilator support. As an alternative to mechanical ventilation, stimulation of the phrenic nerve with electrodes implanted in the diaphragm is gaining acceptance. There is a need, however, to improve diaphragm stimulation and to add abdominal and upper thorax intercostal muscle stimulation for improved respiration and cough. We will test a new electrode for these applications, the PermalocTM bipolar multi-contact (P-BMC;Synapse Biomedical Inc) in an animal model. Respiratory responses with the P-BMC will also be enhanced by using a high current respiratory stimulator and a biphasic stimulating wave form. Results of this study are expected to contribute to technology transfer of the new electrode for cervical-level SCI patient's respiratory care including Veterans Administration SCI patients.
