Risk of gas embolism in hand-assisted versus total laparoscopic hepatic resection

Laparoscopic hepatic resection represents an alternative to open surgery in patients with advanced underlying hepatic disease. Management of haemorrhage and the risk of gas embolism are the major problems in laparoscopic liver surgery. In this study, safety and efficacy of liver dissection using ultrasonic energy was investigated in hand-assisted versus total laparoscopic surgery. The study had a special emphasis on evaluating the risk of gas embolism during both procedures. Female pigs were divided into two groups for A) total laparoscopic (n=7), and B) hand-assisted laparoscopic (n=7) hepatic resection. For tissue dissection, an ultrasound aspirator (CUSA) was used in both groups. Laparoscopic procedure was performed under a CO2 pneumoperitoneum (intraperitoneal pressure: 12 mmHg). Before dissection, a Pringle manoeuver was carried out. The anaesthetized pigs were monitored haemodynamically by an arterial line and Swan-Ganz catheter. Transoesophageal echocardiography (TEE) was performed with special attention to the right atrium and ventricle. Gas emboli were graded according to size and correlated with haemodynamic and blood-gas data. In both groups, the ultrasound-aspirator enabled an effective tissue dissection. In total laparoscopic hepatic resection, TEE monitoring disclosed gas embolism in 5/7 (71%) animals. In 3/7 (42%) animals, gas embolism was accompanied by a sequence of cardiac arrhythmia. No direct correlation was noted between episodes of embolism and blood-gas variables. None of the pigs died after episodes of embolization. In hand-assisted liver resection, no air embolism was noted. The internal hand impressively facilitated organ exposure and provided an immediate and efficient haemorrhage control. The use of an ultrasound aspirator system enables an effective laparoscopic hepatic dissection. Total laparoscopic liver dissection is at increased risk for gas embolism, whereas hand-assisted laparoscopic procedure appears to reduce this risk. Due to tactile response and facilitated retraction of the liver parenchyma, the hand-assisted procedure shows impressive advantages in laparoscopic liver surgery.