Gas embolism during laparoscopic liver resection in a pig model: frequency and severity

A portent of catastrophic carbon dioxide embolism in laparoscopic hepatectomy: A case report

INTRODUCTION

Laparoscopic hepatectomy (LH) poses a high risk of carbon dioxide embolism due to extensive hepatic transection, long surgery duration, and dissection of the large hepatic veins or vena cava.

PATIENT CONCERNS

A 65-year-old man was scheduled to undergo LH. Following intraperitoneal carbon dioxide (CO2) insufflation and hepatic portal occlusion, the patient developed severe hemodynamic collapse accompanied by a decrease in the pulse oxygen saturation (SpO2).

DIAGNOSIS

Although a decrease in end-tidal carbon dioxide (ETCO2) was not observed, CO2 embolism was still suspected because of the symptoms.

INTERVENTIONS AND OUTCOMES

The patient was successfully resuscitated after the immediate discontinuation of CO2 insufflation and inotrope administration. CO2 embolism must always be suspected during laparoscopic surgery whenever sudden hemodynamic collapse associated with decreased pulse oxygen saturation occurs, regardless of whether ETCO2 changes. Instant arterial blood gas analysis is imperative, and a significant difference between PaCO2 and ETCO2 is indicative of carbon dioxide embolism.

CONCLUSION

Instant arterial blood gas analysis is imperative, and a significant difference between PaCO2 and ETCO2 is indicative of carbon dioxide embolism.

Low Pneumoperitoneum Pressure Reduces Gas Embolism During Laparoscopic Liver Resection: A Randomized Controlled Trial

OBJECTIVE

To compare the effect of low and standard pneumoperitoneal pressure (PP) on the occurrence of gas embolism during laparoscopic liver resection (LLR).

BACKGROUND

LLR has an increased risk of gas embolism. Although animal studies have shown that low PP reduces the occurrence of gas embolism, clinical evidence is lacking.

METHODS

This parallel, dual-arm, double-blind, randomized controlled trial included 141 patients undergoing elective LLR. Patients were randomized into standard ("S," 15 mm Hg; n = 70) or low ("L," 10 mm Hg; n = 71) PP groups. Severe gas embolism (≥ grade 3, based on the Schmandra microbubble method) was detected using transesophageal echocardiography and recorded as the primary outcome. Intraoperative vital signs and postoperative recovery profiles were also evaluated.

RESULTS

Fewer severe gas embolism cases (n = 29, 40.8% vs n = 47, 67.1%, P = 0.003), fewer abrupt decreases in end-tidal carbon dioxide partial pressure, shorter severe gas embolism duration, less peripheral oxygen saturation reduction, and fewer increases in heart rate and lactate during gas embolization episodes was found in group L than in group S. Moreover, a higher arterial partial pressure of oxygen and peripheral oxygen saturation were observed, and fewer fluids and vasoactive drugs were administered in group L than in group S. In both groups, the distensibility index of the inferior vena cava negatively correlated with central venous pressure throughout LLR, and a comparable quality of recovery was observed.

CONCLUSIONS

Low PP reduced the incidence and duration of severe gas embolism and achieved steadier hemodynamics and vital signs during LLR. Therefore, a low PP strategy can be considered a valuable choice for the future LLR.

Changes in lung mechanics and ventilation-perfusion match: comparison of pulmonary air- and thromboembolism in rats

BACKGROUND

Pulmonary air embolism (AE) and thromboembolism lead to severe ventilation-perfusion defects. The spatial distribution of pulmonary perfusion dysfunctions differs substantially in the two pulmonary embolism pathologies, and the effects on respiratory mechanics, gas exchange, and ventilation-perfusion match have not been compared within a study. Therefore, we compared changes in indices reflecting airway and respiratory tissue mechanics, gas exchange, and capnography when pulmonary embolism was induced by venous injection of air as a model of gas embolism or by clamping the main pulmonary artery to mimic severe thromboembolism.

METHODS

Anesthetized and mechanically ventilated rats (n = 9) were measured under baseline conditions after inducing pulmonary AE by injecting 0.1 mL air into the femoral vein and after occluding the left pulmonary artery (LPAO). Changes in mechanical parameters were assessed by forced oscillations to measure airway resistance, lung tissue damping, and elastance. The arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were determined by blood gas analyses. Gas exchange indices were also assessed by measuring end-tidal CO2 concentration (ETCO2), shape factors, and dead space parameters by volumetric capnography.

RESULTS

In the presence of a uniform decrease in ETCO2 in the two embolism models, marked elevations in the bronchial tone and compromised lung tissue mechanics were noted after LPAO, whereas AE did not affect lung mechanics. Conversely, only AE deteriorated PaO2, and PaCO2, while LPAO did not affect these outcomes. Neither AE nor LPAO caused changes in the anatomical or physiological dead space, while both embolism models resulted in elevated alveolar dead space indices incorporating intrapulmonary shunting.

CONCLUSIONS

Our findings indicate that severe focal hypocapnia following LPAO triggers bronchoconstriction redirecting airflow to well-perfused lung areas, thereby maintaining normal oxygenation, and the CO2 elimination ability of the lungs. However, hypocapnia in diffuse pulmonary perfusion after AE may not reach the threshold level to induce lung mechanical changes; thus, the compensatory mechanisms to match ventilation to perfusion are activated less effectively.

An abrupt decrease in arterial blood pressure may predict a high level carbon dioxide embolism in retroperitoneoscopic surgery: case report and a literature review

BACKGROUND

Carbon dioxide (CO₂) embolism is the primary suspect in most cases of intraoperative "cardiovascular" collapse. However, there are few reports about CO₂ embolism in retroperitoneal laparoscopy.

CASE PRESENTATION

An abrupt decrease in arterial blood pressure was noted in time of retroperitoneoscopic adrenalectomy in a 40 years old male patient with adrenal adenoma. The end-tidal carbon dioxide (EtCO₂) and saturation of oxygen were stable with normal cardiography until anesthesiologists found the change of resistant of peripheral circulation, then they gave us a hint of hemorrhage. However, the blood pressure had no reaction to one bolus of epinephrine administration when trying to improve the circulation. Five minutes later, a sudden fall of blood pressure was noted, and then we stopped the processing of cutting tissue and trying to coagulate any bleeding in the operation field. Further vasopressor support proved to be completely ineffective. With the help of transesophageal echocardiography, we found the bubbles in the right atrium, which confirmed the diagnosis of an intraoperative gas embolism (Grade IV). We stopped the carbon dioxide insufflation and deflated the retroperitoneal cavity. All the bubbles in the right atrium totally disappeared and the blood pressure, resistance of peripheral circulation and cardiac output returned to normal 20 min later. We continued the operation and completed it in 40 min with the 10 mmHg air pressure.

CONCLUSION

CO₂ embolism may occour during retroperitoneoscopic adrenalectomy, and an acute decrease in arterial blood pressure should alert both the urologists and anesthesiologists to this rare and fatal complication.

Treatment of hepatic venous system hemorrhage and carbon dioxide gas embolization during laparoscopic hepatectomy via hepatic vein approach

With the improvement of laparoscopic surgery, the feasibility and safety of laparoscopic hepatectomy have been affirmed, but intraoperative hepatic venous system hemorrhage and carbon dioxide gas embolism are the difficulties in laparoscopic hepatectomy. The incidence of preoperative hemorrhage and carbon dioxide gas embolism could be reduced through preoperative imaging evaluation, reasonable liver blood flow blocking method, appropriate liver-breaking device, controlled low-center venous pressure technology, and fine-precision precision operation. In the case of blood vessel rupture bleeding in the liver vein system, after controlling and reducing bleeding, confirm the type and severity of vascular damage in the liver and venous system, take appropriate measures to stop the bleeding quickly and effectively, and, if necessary, transfer the abdominal treatment in time. In addition, to strengthen the understanding, prevention and emergency treatment of severe CO2 gas embolism in laparoscopic hepatectomy is also the key to the success of surgery. This study aims to investigate the methods to deal with hepatic venous system hemorrhage and carbon dioxide gas embolization based on author's institutional experience and relevant literature. We retrospectively analyzed the data of 60 patients who received laparoscopic anatomical hepatectomy of hepatic vein approach for HCC. For patients with intraoperative complications, corresponding treatments were given to cope with different complications. After the operation, combined with clinical experience and literature, we summarized and discussed the good treatment methods in the face of such situations so that minimize the harm to patients as much as possible.

Trends in Minimally Invasive Approaches for Liver Resections-A Systematic Review

BACKGROUND

SILS (single incision laparoscopic surgery) and NOTES (natural orifice transluminal endoscopic surgery) are considered breakthroughs in minimally invasive surgery, the first consisting in the surgeon working via a single entrance site and the second via a natural orifice (e.g., oral cavity).

METHODS

Since 2000 until 2022, the original articles published in the online databases were analyzed. Eligible studies included information about the current therapy of patients with liver surgical pathology and how the two new techniques improve the surgical approach.

RESULTS

A total of 798 studies were identified. By applying the exclusion criteria, nine studies remained to be included in the review. Two out of nine studies examined the NOTES approach in liver surgery, whereas the other seven focused on the SILS technique. The age of the patients ranged between 24 and 83 years. Liver resections for hepatocellular carcinoma or colorectal metastases were undertaken and biliary or hydatid cysts were removed. The mean procedure time was 95 to 205 min and the average diameter of the lesions was 5 cm.

CONCLUSIONS

When practiced by multidisciplinary teams, transvaginal liver resection is feasible and safe. The goals of SILS and NOTES are to be less intrusive, more easily tolerated and aesthetic.

New 5-mm laparoscopic pneumodissector device to improve laparoscopic dissection: an experimental study of its safety in a swine model

BACKGROUND

To improve the laparoscopic surgical dissection, the aim of the study was to assess the safety of burst of high-pressure CO₂ using a 5-mm laparoscopic pneumodissector (PD) operating at different flow rates and for different operating times regarding the risk of gas embolism (GE) in a swine model.

METHODS

The first step was to define the settings use of the PD device ensuring no GE. Successive procedures were conducted by laparotomy: cholecystectomy, the PD was placed 10 mm deep in the liver and the PD was directly introduced into the lumen of the inferior vena cava. Different PD flow rates of 5, 10, and 15 mL/s were used. The second step was to assess the safety of the device (PD group) during a laparoscopic dissection task (cystic and hepatic pedicles dissection, cholecystectomy and right nephrectomy) in comparison with the use of a standard laparoscopic hook device (control group). PD flow rate was 10 mL/s and consecutive burst of high-pressure CO₂ was delivered for 3-5 s.

RESULTS

In the first step (n = 17 swine), no GE occurred during cholecystectomy regardless of the PD flow rate used. When the PD was placed in the liver or into the inferior vena cava, no severe or fatal GE occurred when a burst of high-pressure CO₂ was applied for 3 or 5 s with PD flow rates of 5 and 10 mL/s. In the second step (PD group, n = 10; control group, n = 10), no GE occurred in the PD group. The use of the PD did not increase operative time or blood loss. The quality of the dissection was significantly improved compared to the control group.

CONCLUSIONS

The 5-mm laparoscopic PD appears to be free from CO₂ GE risk when consecutive bursts of high-pressure CO₂ are delivered for 3-5 s with a flow rate of 10 mL/s.

Comparison of a new gasless method and the conventional CO2 pneumoperitoneum method in laparoendoscopic single-site cholecystectomy: a prospective randomized clinical trial

To avoid CO₂ pneumoperitoneum-associated cardiopulmonary side-effects during conventional laparoscopic surgeries, we have developed a gasless laparoscopic operation field formation (LOFF) device for laparoendoscopic single-site surgery. The aim of this study is to analyze the safety and efficacy of the LOFF device for laparoendoscopic single-site cholecystectomy and to verify its advantage of avoiding CO₂ pneumoperitoneum-associated complications. In this prospective, randomized, observer-blinded clinical trial, eligible participants were randomized in a 1:1 ratio to undergo either conventional CO₂ pneumoperitoneum assisted laparoendoscopic single-site cholecystectomy (LESS) or the new gasless LOFF device assisted laparoendoscopic single-site cholecystectomy (LOFF-LESS). Outcomes including intra-operative respiratory and hemodynamic parameters, operation time, conversion rate, complication rate, et al were compared between the two groups. A total of 100 patients were randomized to the LESS group [n = 50; mean (SD) age, 49.5 (13.9) years; 24 (48.0%) women] and the LOFF-LESS group [n = 50, mean (SD) age, 47.4 (13.3) years; 27 (54.0%) women]. Compared with the LOFF-LESS group, the LESS group witnessed significant fluctuations in intra-operative respiratory and hemodynamic parameters. The tracheal extubation time of the LESS group was significantly longer (P = 0.001). The gasless LOFF device is safe and feasible for simple laparoscopic cholecystectomy and has a predominance of avoiding CO₂ pneumoperitoneum-associated cardiopulmonary side-effects. Trial registration number: ChiCTR2000033702.

Carbon dioxide embolism with severe hypotension as an initial symptom during laparoscopy: a case report

Laparoscopy is widely used because it induces minimal postoperative pain and facilitates rapid recovery. However, carbon dioxide (CO₂) embolism is a rare but potentially fatal complication of laparoscopic surgery. Earlier reports have shown that decreased end-tidal CO₂ (ETCO₂) and increased partial pressure of CO₂ might be useful indicators of CO₂ embolism. We herein report a case of CO₂ embolism after the freed bladder neck was released during laparoscopic radical prostatectomy. Sudden hemodynamic disorder and increased ETCO₂ combined with immediate arterial blood gas analysis led us to suspect CO₂ embolism, which was confirmed by the aspiration of foamy blood from the central venous catheter. The patient was successfully resuscitated and recovered well. This case illustrates that hemodynamic collapse accompanied by increased ETCO₂ can indicate CO₂ embolism.

Robotic hepatic parenchymal transection: a two-surgeon technique using ultrasonic dissection and irrigated bipolar coagulation

Liver transection is the most challenging part of hepatectomy due to the risk of hemorrhage which is associated with postoperative morbidity and mortality and reduced long-term survival. Parenchymal ultrasonic dissection (UD) with bipolar coagulation (BPC) has been widely recognized as a safe, effective, and standard technique during open and laparoscopic hepatectomy. We here introduce our technique of robotic liver transection using UD with BPC and report on short-term perioperative outcomes. From a single-institution prospective liver surgery database, we identified patients who underwent robotic liver resection. Demographic, anesthetic, perioperative, and oncologic data were analyzed. Fifty patients underwent robotic liver resection using UD and BPC for liver malignancies (n = 42) and benign lesions (n = 8). The median age of the patients was 67 years and 28 were male. According to the difficulty scoring system, 60% (n = 30) of liver resection were considered difficult. Three cases (6%) were converted to open surgery. The median operative time was 240 min, and the median estimated blood loss was 200 ml; 2 patients required operative transfusions. The overall complication rate was 38% (grade I, 29; grade II, 15; grade III, 3; grade IV, 1). Seven patients (14%) experienced biliary leakage. The median length of hospital stay post-surgery was 7 (range 3-20) days. The R0 resection rate was 92%. Robotic parenchymal transection using UD and irrigated BPC appears a simple, safe, and effective technique. However, our results must be confirmed in larger series or in randomized controlled trials.

An abnormal capnography trace due to air embolism in the lateral position

Venous air embolism occurs when air is entrained into the venous system and travels to the right heart and pulmonary circulation, and commonly occurs as a complication in laparoscopic, neurosurgical and cardiac surgeries. We present a case of abnormal end-tidal carbon dioxide capnography tracing in the lateral position in a laparoscopic major liver procedure and discuss the potential novel use of this as a red flag in aiding the medical practitioner to diagnose air embolism.

Infrahepatic inferior vena cava clamping with Pringle maneuvers for laparoscopic extracapsular enucleation of giant liver hemangiomas

Background

This study aimed to determine the feasibility of the extracapsular enucleation method for giant liver hemangiomas by infrahepatic inferior vena cava (IVC) clamping and the Pringle maneuver to control intraoperative bleeding under laparoscopic hepatectomy.

Methods

From January 2012 to January 2016, 36 patients underwent laparoscopic extracapsular enucleation of giant liver hemangiomas. Patients were divided into two groups: infrahepatic IVC clamping + Pringle maneuvers group (IVCP group, n = 15) and the Pringle maneuvers group (Pringle group, n = 21). Operative parameters, postoperative laboratory tests, and morbidity and mortality were analyzed.

Results

The mean size of liver hemangiomas was 13.3 cm (range 10–25 cm). Infrahepatic IVC clamping + the Pringle maneuvers with laparoscopic extracapsular enucleation significantly reduced intraoperative blood loss (586.7 vs 315.3 mL, p < 0.001) and transfusion rates (23.8 vs 6.7%, p = 0.001), compared with the Pringle maneuver alone. The gallbladder was retained in both groups. The mean arterial pressure (MAP) in Pringle group remained virtually stable before and after clamping of hepatic portal, while it was significantly decreased after IVC clamping in IVCP group than that pre-clamping (p < 0.001). The heart rate of all patients was significantly increased after clamping when compared to pre-clamping heart rates (p < 0.001). Once vascular occlusion was released, MAP returned to normal levels within a few minutes. There were no significant differences in postoperative complications between two groups. The vascular occlusion techniques in both groups had no serious effect on postoperative of hepatic and renal function.

Conclusions

Extracapsular enucleation with infrahepatic IVC clamping + the Pringle maneuver is a safe and effective surgical treatment to control bleeding for giant liver hemangiomas in laparoscopic hepatectomy.

Transumbilical single-incision laparoscopic resection of focal hepatic lesions

Background and Objectives:

Transumbilical single-incision laparoscopic surgery (SILS) is gaining in popularity as a minimally invasive technique. The reduced pain and superior cosmetic appearance it affords make it attractive to many patients. For this study, we focused on SILS, analyzing the outcomes of transumbilical single-incision laparoscopic liver resection (SILLR) achieved at our institution between January 2010 and February 2013.

Patients and Methods:

Pre- and postoperative data from 17 patients subjected to transumbilical SILLR for various hepatic lesions (8 hemangiomas, 2 hepatocellular carcinomas, 2 metastases, 2 calculi of left intrahepatic duct, and 3 adenomas) were assessed. Altogether, eight wedge resections, seven left lateral lobectomies, a combination wedge resection/left lateral lobectomy, and a proximal left hemihepatectomy segmentectomy were performed, as well as four simultaneous laparoscopic cholecystectomies. In each instance, three ports were installed through an umbilical incision. Once vessels and bleeding were controlled, the lesion(s) were resected with 5-mm margins of normal liver. Resected tissues were then bagged and withdrawn through the umbilical incision. The follow-up period lasted for a minimum of 6 months.

Results:

All 17 patients were successfully treated through a single umbilical incision. The procedures required 55 to 185 minutes to complete, with blood loss of 30 to 830 mL. Subjects regained bowel activity 0.8 to 2.3 days postoperatively and were discharged after 3 to 10 days. There were few complications (23.5%), limited to pleural effusion, wound infection, and incisional hernia.

Conclusions:

Transumbilical SILLR is challenging to perform through conventional laparoscopic instrumentation. The risk of bleeding and technical difficulties is high for lesions of the posterosuperior hepatic segment. Surgical candidates should be carefully selected to optimize the benefits of this technique.

Laparoscopic liver resection: Experience based guidelines

Laparoscopic liver resection (LLR) has been progressively developed along the past two decades. Despite initial skepticism, improved operative results made laparoscopic approach incorporated to surgical practice and operations increased in frequency and complexity. Evidence supporting LLR comes from case-series, comparative studies and meta-analysis. Despite lack of level 1 evidence, the body of literature is stronger and existing data confirms the safety, feasibility and benefits of laparoscopic approach when compared to open resection. Indications for LLR do not differ from those for open surgery. They include benign and malignant (both primary and metastatic) tumors and living donor liver harvesting. Currently, resection of lesions located on anterolateral segments and left lateral sectionectomy are performed systematically by laparoscopy in hepatobiliary specialized centers. Resection of lesions located on posterosuperior segments (1, 4a, 7, 8) and major liver resections were shown to be feasible but remain technically demanding procedures, which should be reserved to experienced surgeons. Hand-assisted and laparoscopy-assisted procedures appeared to increase the indications of minimally invasive liver surgery and are useful strategies applied to difficult and major resections. LLR proved to be safe for malignant lesions and offers some short-term advantages over open resection. Oncological results including resection margin status and long-term survival were not inferior to open resection. At present, surgical community expects high quality studies to base the already perceived better outcomes achieved by laparoscopy in major centers’ practice. Continuous surgical training, as well as new technologies should augment the application of laparoscopic liver surgery. Future applicability of new technologies such as robot assistance and image-guided surgery is still under investigation.

Anesthesia for Endoscopy

Anesthesia for endoscopic surgery can be challenging depending on surgical manipulations and patient comorbidity. Anesthetists must understand the possible systemic changes and complications that are associated with endoscopic surgery. Pneumoperitoneum induces vasoconstriction, reduces cardiac output, and decreases functional residual capacity in the cardiopulmonary system. Both hypoventilation caused by the thoracoscopic procedure and CO2 insufflation increase Paco2. To prevent the problems associated with high Paco2, monitoring of end-tidal CO2 (ETco2) and capability of positive pressure ventilation are crucial. Sudden changes of ETco2 should be monitored closely. Endoscopic surgery should be a less invasive procedure; however, appropriate analgesia remains necessary.

High-frequency jet ventilation shortened the duration of gas embolization during laparoscopic liver resection in a porcine model

BACKGROUND

Positive pressure mechanical ventilation causes rhythmic changes in thoracic pressure and central blood flow. If entrainment occurs, it could be easier for carbon dioxide to enter through a wounded vein during laparoscopic liver lobe resection (LLR). High-frequency jet ventilation (HFJV) is a ventilating method that does not cause pronounced pressure or blood flow changes. This study aimed to investigate whether HFJV could influence the frequency, severity, or duration of gas embolism (GE) during LLR.

METHODS

Twenty-four anaesthetized piglets underwent lobe resection and were randomly assigned to either normal frequency ventilation (NFV) or HFJV (n=12 per group). During resection, a standardized injury to the left hepatic vein was created to increase the risk of GE. Haemodynamic and respiratory variables were monitored. Online blood gas monitoring and transoesophageal echocardiography were used. GE occurrence and severity were graded as 0 (none), 1 (minor), or 2 (major), depending on the echocardiography results.

RESULTS

GE duration was shorter in the HFJV group (P=0.008). However, no differences were found between the two groups in the frequency or severity of embolism. Incidence of Grade 2 embolism was less than that found in previous studies and physiological responses to embolism were variable.

CONCLUSION

HFJV shortened the mean duration of GE during LLR and was a feasible ventilation method during the procedure. Individual physiological responses to GE were unpredictable.

Laparoscopic major hepatectomy: a systematic literature review and comparison of 3 techniques

OBJECTIVE

This review assesses the current status of laparoscopic liver resection.

BACKGROUND

The trend in laparoscopic liver resection has been moving from limited resections toward major hepatectomy. The surgical techniques for laparoscopic major hepatectomy include pure laparoscopic, hand-assisted laparoscopic, and laparoscopy-assisted methods. We performed a literature search and systematic review to assess the current status of laparoscopic major hepatectomy.

METHODS

Our literature review was conducted in Medline using the keywords "laparoscopy" or "laparoscopic" combined with "liver resection" or "hepatectomy." Articles written in English containing more than 10 cases of laparoscopic major hepatectomy were selected.

RESULTS AND CONCLUSIONS

Twenty-nine articles were selected for this review. The laparoscopic major hepatectomies achieved similar patient and economic outcomes compared with open liver resections in selected (noncirrhotic) patients. Surgeon experience with the techniques affected the results; thus, a learning period is mandatory. Of these 3 techniques, the pure laparoscopic method is suitable for experienced surgeons to achieve better cosmetic outcomes, whereas the hand-assisted laparoscopic method was associated with better perioperative outcomes; the laparoscopy-assisted method is used by surgeons for unique resections such as resection of cirrhotic livers, laparoscopic resection of tumors in unfavorable locations, and living donor hepatectomies. In addition, the laparoscopic major hepatectomy-specific, long-term oncologic outcomes remain to be addressed in future publications.

Resuscitation by hyperbaric exposure from a venous gas emboli following laparoscopic surgery

Venous gas embolism is common after laparoscopic surgery but is only rarely of clinical relevance. We present a 52 year old woman undergoing laparoscopic treatment for liver cysts, who also underwent cholecystectomy. She was successfully extubated. However, after a few minutes she developed cardiac arrest due to a venous carbon dioxide (CO₂) embolism as identified by transthoracic echocardiography and aspiration of approximately 7 ml of gas from a central venous catheter. She was resuscitated and subsequently treated with hyperbaric oxygen to reduce the size of remaining gas bubbles. Subsequently the patient developed one more episode of cardiac arrest but still made a full recovery. The courses of events indicate that bubbles had persisted in the circulation for a prolonged period. We speculate whether insufficient CO₂ flushing of the laparoscopic tubing, causing air to enter the peritoneal cavity, could have contributed to the formation of the intravascular gas emboli. We conclude that persistent resuscitation followed by hyperbaric oxygen treatment after venous gas emboli contributed to the elimination of intravascular bubbles and the favourable outcome for the patient.

Elevated PEEP without effect upon gas embolism frequency or severity in experimental laparoscopic liver resection

BACKGROUND

Carbon dioxide (CO(2)) embolism is a potential complication in laparoscopic liver surgery. Gas embolism (GE) is thought to occur when central venous pressure (CVP) is lower than the intra-abdominal pressure (IAP). This study aimed to investigate whether an increased CVP due to induction of PEEP could influence the frequency and severity of GE during laparoscopic liver resection.

METHODS

Twenty anaesthetized piglets underwent laparoscopic left liver lobe resection and were randomly assigned to either 5 or 15 cm H(2)O PEEP (n=10 per group). During resection, a standardized injury to the left hepatic vein [venous cut (VC)] was created to increase the risk of GE. Haemodynamic and respiratory variables were monitored, and online arterial blood gas monitoring and transoesophageal echocardiography (TOE) were used. The occurrence and severity of embolism was graded as 0 (none), 1 (minor), or 2 (major), depending on the TOE results.

RESULTS

No differences were found between the two groups regarding the frequency or severity of GE, during either the VC (P=0.65) or the rest of the surgery (P=0.24). GE occurred irrespective of the CVP-IAP gradient.

CONCLUSIONS

Mechanisms other than the CVP-IAP gradient seemed during laparoscopic liver surgery to contribute to the formation of CO(2) embolism. This is of clinical importance to the anaesthetists.

Laparoscopic liver surgery: new frontiers

Laparoscopic liver resection (LHR) has shown classical advantages of minimally invasive surgery over open counterpart. In spite of introduction in early 1990's only few centres worldwide adapted LHR to routine practice. It was due to considerable technical challenges and uncertainty about oncologic outcomes. Surgical instrumentation and accumulation of surgical experience has largely enabled to solve many technical considerations. Intraoperative navigation options have also been improved. Consequently indications have been drastically expanded nearly reaching criteria equal to open liver resection in expert centres. Recent studies have verified oncologic integrity of LHR. However, mastering of LHR is still a quite demanding task limiting expansion of this patient friendly technique. This emphasizes the necessity of systematic training for laparoscopic liver surgery. This article reviews the state of the art of laparoscopic liver surgery lightening burning issues of research and clinical practice.

High intra-abdominal pressure during experimental laparoscopic liver resection reduces bleeding but increases the risk of gas embolism

BACKGROUND

Various recommendations exist regarding intra-abdominal pressure (IAP) during laparoscopic liver resection. A high IAP may reduce bleeding but at the same time increase the risk of gas embolism. This study investigated the effects of two different IAPs during laparoscopic left liver lobe resection in piglets.

METHODS

Sixteen piglets underwent laparoscopic left liver lobe resection using carbon dioxide pneumoperitoneum of either 8 or 16 mmHg (8 per group). A combination of CUSA System 200™ and LigaSure™ instruments was used for parenchymal division. During resection, a standard injury to the left liver vein was also created to increase the risk of bleeding and/or gas embolism during the operation. Heart rate, cardiac output, and arterial, pulmonary arterial, pulmonary capillary wedge and central venous pressures were measured. Arterial blood gases were monitored continuously. Transoesophageal echocardiography was video recorded to detect and quantify gas embolism within the right cardiac ventricle. The duration of operation and bleeding were noted.

RESULTS

High IAP resulted in reduced bleeding (P = 0·016), but gas embolism occurred more frequently (P = 0·001) than with low IAP. Gas embolism disturbed gas exchange, with an increase in arterial pressure of carbon dioxide, and a decrease in arterial partial pressure of oxygen and pH. These effects were sustained for at least 30 min after surgery.

CONCLUSION

High IAP reduces the amount of bleeding but increases the risk of gas embolism. Monitoring for gas embolism is therefore indicated if a high IAP is used during laparoscopic liver resection.