Autonomic Nervous System Implantation

Eight dogs were intubated and anesthetized with isoflurane. A left thoracotomy was performed for the implantation of a radiotransmitter (D70EEE, Data Sciences International, St. Paul, MN) to record SGNA and VNA according to methods reported previously.^{1 (link)–4 (link)} A third pair of bipolar electrodes was placed in the subcutaneous space through the same thoracotomy wound. In the first 7 dogs, one electrode was inserted approximately 5–10 cm cranially into the subcutaneous tissues of the upper thorax, while the other was inserted caudally for the same distance into the subcutaneous tissues of the left abdomen. The inserted device and leads were fixed into the subcutaneous pocket with multiple interrupted sutures to minimize the movements of the electrodes. In an 8^th dog, we used the second pair of electrodes to record closely spaced (approximately 4 cm apart) SCNA instead of VNA 10 days after left thoracotomy. After 2 weeks of recovery, the radiotransmitter was turned on to continuously record from all 3 electrodes at a sampling rate of 1,000/s.