<prompt> Shoulder pain post laparoscopy is due toSubphrenic abscessCO2 retentionPositioning of the patientCompression of the lung  <response>: Laparoscopy Needle used for pneumoperitoneum : Veress needle Most commonly used gas: CO2 Flow of gas : 1Lmin Intra abdominal pressure : 12-15mmHg Trocar is inseed at or just below the umbilicus penetrating skin, superficial deep fascia, fascia transversalis parietal peritoneum Post-laparoscopy shoulder pain is due a to CO2 retention causing irritation of diaphragm referred pain to the shoulder through phrenic nerve Ref: Sabiston 20th edition Pgno : 394-396 