We appreciate the comments and questions from Drs. Dubar and Fischler regarding our article.1 

We agree that the detection of a patent foramen ovale (PFO) would have been enhanced if we had used the methods that they had recommended. Because the incidence of PFO in Koreans has been well known,2,3our focus was not the incidence of PFO in this study.

We also tried to find bubbles in the left heart, especially PFO cases and any neurologic complications after surgery, but we did not find any. However, if we had conducted postoperative cognitive function test, such as the Mini Mental State Examination,4minor neurologic complications might have been found.

Although animal studies found no benefit from the left-lateral decubitus (Durant's) position in improving hemodynamic performance, it can allow gas bubbles to rise into the apex of the right atrium. So, it may be helpful for trapping and aspirating bubbles entrained in the right atrium.

As one of the specialists in diving medicine, the corresponding author (K.J.K.) totally agrees with them that hyperbaric oxygen therapy has potential benefits for arterial air embolism and cerebral air embolism.

The major reason why systemic complications resulting from paradoxical embolism with carbon dioxide are rare may be because of the high solubility of carbon dioxide in blood (0.60 ml CO2/ml blood).5Air embolism can be rapidly transformed into a nonair embolism because of the adhesion of platelets to the bubble, as they had pointed out. However, endothelial cells are important because they can be damaged by bubbles that are small enough to pass through the blood circulation without obstructing the blood flow.

In contrast to laparotomy, laparoscopic surgery has several benefits such as improved and more rapid recovery, reduced postoperative fatigue, heightened feeling of well-being, and better maintenance of homeostasis.6–8Moreover, clinically significant carbon dioxide embolism is rare (0.001%) during laparoscopic procedures9,10unlike PFO whose incidence is relatively high. Therefore, we believe that PFO cannot be a ground for eliminating laparoscopic surgery from possible surgical treatments.

*Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea. kkj6063@yuhs.ac

Kim CS, Kim JY, Kwon JY, Choi SH, Na S, An J, Kim KJ: Venous air embolism during total laparoscopic hysterectomy: Comparison to total abdominal hysterectomy. Anesthesiology 2009; 111:50–4
Chang DI, Lee MS, Cho SH, Bu SH, Chung SH, Huh SH, Yoon KU, Ahn TB, Yoon SS, Chung KC: Incidence of patent foramen ovale in ischemic stroke patients: A transcranial Doppler study. J Korean Neurol Assoc 2005; 23:313–7
Hwang HK, Hong SK, Kim MA, Lee SH, Kim PG, Moon HS, Lee SM: Intraoperative detection of patent foramen ovale by transesophageal echocardiography. J Korean Soc Echocardiogr 1993; 1:97–101
Choi SH, Lee SJ, Jung Y, Shin YS, Jun DB, Hwang KH, Liu J, Kim KJ: Nitroglycerin- and nicardipine-induced hypotension does not affect cerebral oxygen saturation and postoperative cognitive function in patients undergoing orthognathic surgery. J Oral Maxillofac Surg 2008; 66:2104–9
Longnecker DE, Murphy FL: Introduction to Anesthesia, 9th edition. Philadelphia, WB Saunders Co, 1997, pp 130
WB Saunders Co
Jakeways MS, Mitchell V, Hashim IA, Chadwick SJ, Shenkin A, Green CJ, Carli F: Metabolic and inflammatory responses after open or laparoscopic cholecystectomy. Br J Surg 1994; 81:127–31
Delaunay L, Bonnet F, Cherqui D, Rimaniol JM, Dahan E, Atlan G: Laparoscopic cholecystectomy minimally impairs postoperative cardiorespiratory and muscle performance. Br J Surg 1995; 82:373–6
Joris J, Cigarini I, Legrand M, Jacquet N, De Groote D, Franchimont P, Lamy M: Metabolic and respiratory changes after cholecystectomy performed via laparotomy or laparoscopy. Br J Anaesth 1992; 69:341–5
Bonjer HJ, Hazebroek EJ, Kazemier G, Giuffrida MC, Meijer WS, Lange JF: Open versus closed establishment of pneumoperitonium in laparoscopic surgery. Br J Surg 1997; 84:599–602
Mintz M: Risks and prophylaxis in laparoscopy: A survey of 100.000 cases. J Reprod Med 1977; 18:269–72