Small-Incision Laparoscopy-Assisted Surgery Under Abdominal Cavity Irrigation in a Porcine Model.

BACKGROUND: Laparoscopic and robot-assisted surgeries are performed under carbon dioxide insufflation. Switching from gas to an isotonic irrigant introduces several benefits and avoids some adverse effects of gas insufflation. We developed an irrigating device and apparatus designed for single-incision laparoscopic surgery and tested its advantages and drawbacks during surgery in a porcine model. MATERIALS AND METHODS: Six pigs underwent surgical procedures under general anesthesia. A 30-cm extracorporeal cistern was placed over a 5-6-cm abdominal incision. The abdomen was irrigated with warm saline that was drained via a suction tube placed near the surgical field and continuously recirculated through a closed circuit equipped with a hemodialyzer as a filter. Irrigant samples from two pigs were cultured to check for bacterial and fungal contamination. Body weight was measured before and after surgery in four pigs that had not received treatments affecting hemodynamics or causing diuresis. RESULTS: One-way flow of irrigant ensured laparoscopic vision by rinsing blood from the surgical field. Through a retroperitoneal approach, cystoprostatectomy was successfully performed in three pigs, nephrectomy in two, renal excision in two, and partial nephrectomy in one, under simultaneous ultrasonographic monitoring. Through a transperitoneal approach, liver excision and hemostasis with a bipolar sealing device were performed in three pigs, and bladder pedicle excision was performed in one pig. Bacterial and fungal contamination of the irrigant was observed on the draining side of the circuit, but the filter captured the contaminants. Body weight increased by a median of 2.1% (range, 1.2-4.4%) of initial weight after 3-5 hours of irrigation. CONCLUSIONS: Surgery under irrigation is feasible and practical when performed via a cistern through a small abdominal incision. This method is advantageous, especially in the enabling of continuous and free-angle ultrasound observation of parenchymal organs. Adverse effects of abdominal irrigation need further assessment before use in humans.

Effects of withdrawal of phasic lung inflation during normocapnia and hypercapnia on the swallowing reflex in humans.

PURPOSE: This study was done to test the hypothesis that hypercapnia has a direct, inhibitory effect on swallowing. METHODS: We investigated changes in the frequency and timing of repeated swallows induced by continuous infusion of water into the pharynx before, during, and after transient airway occlusion at normocapnia and hypercapnia in 12 healthy volunteers. Hypercapnia was induced by adding a dead space. Ventilation was monitored using a pneumotachograph, and swallowing was identified by submental electromyogram. RESULTS: We found that hypercapnia decreased the frequency of swallows (8.2 +/- 3.7 vs 11.4 +/- 5.3 swallows.min-1 [mean +/- SD]: hypercapnia vs normocapnia; P < 0.05), together with a loss of the preponderant coupling of swallows with expiratory phase observed at normocapnia. We also found that the withdrawal of phasic lung inflation produced by airway occlusion at end-expiration suddenly increased the swallowing frequency, both at normocapnia (from 11.4 +/- 5.3 to 16.7 +/- 3.7 swallows.min-1; P < 0.01) and at hypercapnia (from 8.2 +/- 3.7 to 22.0 +/- 6.7 swallows.min-1; P < 0.01). Although the degree of increased swallowing frequency during airway occlusion was more prominent at hypercapnia than at normocapnia ( P < 0.05), the distribution of the timing of swallows in relation to the phase of the respiratory cycle during airway occlusion at hypercapnia was similar to that during airway occlusion at normocapnia. CONCLUSION: The results of our study strongly suggest that the attenuation of the swallowing reflex during hypercapnia is not due to the direct, inhibitory effect of CO2 on the swallowing center, but, rather, is due to the increased inhibitory influence of a lung-volume-related reflex.