Purpose: Peroral endoscopic myotomy (POEM) is a novel technique for treating esophageal achalasia. During POEM, carbon dioxide (CO2) is insufflated to aid surgical dissection, but it may inadvertently track into surrounding tissues, causing systemic CO2 uptake and tension capnoperitoneum. This in turn may affect cardiorespiratory function. This study quantified these cardiorespiratory effects and treatment by hyperventilation and percutaneous abdominal needle decompression (PND).
Methods: One hundred and seventy-three consecutive patients who underwent POEM were included in this four-year retrospective study. Procedure-related changes in peak inspiratory pressure (pmax), end-tidal CO2 levels (etCO2), minute ventilation (MV), mean arterial pressure (MAP), and heart rate (HR) were analyzed. We also quantified the impact of PND on these cardiorespiratory parameters.
Results: During the endoscopic procedure, cardiorespiratory parameters increased from baseline: pmax 15.1 (4.5) vs 19.8 (4.7) cm H2O; etCO2 4.5 (0.4) vs 5.5 (0.9) kPa [34.0 (2.9) vs 41.6 (6.9) mmHg]; MAP 73.9 (9.7) vs 99.3 (15.2) mmHg; HR 67.6 (12.4) vs 85.3 (16.4) min-1 (P < 0.001 for each). Hyperventilation [MV 5.9 (1.2) vs 9.0 (1.8) L·min-1, P < 0.001] was applied to counteract iatrogenic hypercapnia. Individuals with tension capnoperitoneum treated with PND (n = 55) had higher peak pmax values [22.8 (5.7) vs 18.4 (3.3) cm H2O, P < 0.001] than patients who did not require PND. After PND, pmax [22.8 (5.7) vs 19.9 (4.3) cm H2O, P = 0.045] and MAP [98.2 (16.3) vs 88.6 (11.8) mmHg, P = 0.013] decreased. Adverse events included pneumothorax (n = 1), transient myocardial ischemia (n = 1), and subcutaneous emphysema (n = 49). The latter precluded immediate extubation in eight cases. Postanesthesia care unit (PACU) stay was longer in individuals with subcutaneous emphysema than in those without [74.9 min (34.5) vs 61.5 (26.8 min), P = 0.007].
Conclusion: Carbon dioxide insufflation during POEM produces systemic CO2 uptake and increased intra-abdominal pressure. Changes in cardiorespiratory parameters include increased pmax, etCO2, MAP, and HR. Hyperventilation and PND help mitigate some of these changes. Subcutaneous emphysema is common and may delay extubation and prolong PACU stay.