Carbon dioxide absorption and elimination in breath during minimally invasive surgery

Carbon footprints in minimally invasive surgery: Good patient outcomes, but costly for the environment

Advancements in technology and surgical training programs have increased the adaptability of minimally invasive surgery (MIS). Gastrointestinal MIS is superior to its open counterparts regarding post-operative morbidity and mortality. MIS has become the first-line surgical intervention for some types of gastrointestinal surgery, such as laparoscopic cholecystectomy and appendicectomy. Carbon dioxide (CO2) is the main gas used for insufflation in MIS. CO2 contributes 9%-26% of the greenhouse effect, resulting in global warming. The rise in global CO2 concentration since 2000 is about 20 ppm per decade, up to 10 times faster than any sustained rise in CO2 during the past 800000 years. Since 1970, there has been a steady yet worrying increase in average global temperature by 1.7 °C per century. A recent systematic review of the carbon footprint in MIS showed a range of 6-814 kg of CO2 emission per surgery, with higher CO2 emission following robotic compared to laparoscopic surgery. However, with superior benefits of MIS over open surgery, this poses an ethical dilemma to surgeons. A recent survey in the United Kingdom of 130 surgeons showed that the majority (94%) were concerned with climate change but felt that the lack of leadership was a barrier to improving environmental sustainability. Given the deleterious environmental effects of MIS, this study aims to summarize the trends of MIS and its carbon footprint, awareness and attitudes towards this issue, and efforts and challenges to ensuring environmental sustainability.

Premedication with acetazolamide: Is its use for postoperative pain and stress control after laparoscopic ovariectomy in dogs ruled out?

BACKGROUND

Studies in human medicine have concluded that acetazolamide reduces pain associated with carbon dioxide insufflation during laparoscopic surgery. However, there are no published reports regarding the use of acetazolamide for this purpose in companion animals, despite the increasing popularity of laparoscopic techniques in veterinary medicine due to their advantages over open surgeries.

OBJECTIVES

Thirty mixed-breed female dogs were included in the study and randomly assigned to one of three groups: OVE (median celiotomy ovariectomy; n = 10), OVEL (laparoscopic ovariectomy, n = 10) and OVELA (laparoscopic ovariectomy with acetazolamide preoperative administration; n = 10). Experienced surgeons performed all procedures, and the anaesthetic and analgesic protocols were identical for all animals. Acetazolamide was administered orally (at a dose of 25 mg/kg) 2 h prior to induction in the OVELA group. Postoperative pain was evaluated using serum cortisol, salivary cortisol, and the University of Melbourne Pain Scale (UMPS) Score.

RESULTS

Any statistical differences were observed in the UMPS scores when the OVELA group was compared to the OVEL group at 1 h after surgery (p = 0.515), 12 h (p = 0.375) and 24 h (p = 0.242). Animals undergoing open surgery (OVE group) had significantly higher pain scores at all times after surgery when compared with OVEL and OVELA groups. A high positive correlation (r = 0.792; p = 0.01) was found between serum and saliva cortisol concentrations. Mean saliva cortisol concentration was not significantly lower for the OVELA group compared to the other groups.

CONCLUSIONS

This study found evidence that preoperative administration of acetazolamide may be beneficial in managing postoperative pain in dogs after laparoscopic surgeries. However, further research with a larger sample size is needed to confirm this and to determine if acetazolamide should be included in a multimodal postoperative analgesia protocol for laparoscopic ovariectomy in dogs.

Automated control for investigation of the insufflation-ventilation interaction in experimental laparoscopy

In laparoscopic surgery the abdominal cavity is insufflated with pressurized carbon dioxide gas to create workspace. This pressure is exerted through the diaphragm onto the lungs, competing with ventilation and hampering it. In clinical practice the difficulty of optimizing this balance can lead to the application of harmfully high pressures. This study set out to create a research platform for the investigation of the complex interaction between insufflation and ventilation in an animal model. The research platform was constructed to incorporate insufflation, ventilation and relevant hemodynamic monitoring devices, controlling insufflation and ventilation from a central computer. The core of the applied methodology is the fixation of physiological parameters by applying closed-loop control of specific ventilation parameters. For accurate volumetric measurements the research platform can be used in a CT scanner. An algorithm was designed to keep blood carbon dioxide and oxygen values stable, minimizing the effect of fluctuations on vascular tone and hemodynamics. This design allowed stepwise adjustment of insufflation pressure to measure the effects on ventilation and circulation. A pilot experiment in a porcine model demonstrated adequate platform performance. The developed research platform and protocol automation have the potential to increase translatability and repeatability of animal experiments on the biomechanical interactions between insufflation and ventilation.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery

BACKGROUND

This is the second update of a Cochrane Review first published in 2013 and last updated in 2017. Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum.

OBJECTIVES

To assess the safety, benefits, and harms of different gases (e.g. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic abdominal or gynaecological pelvic surgery.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, Ovid Embase, four other databases, and three trials registers on 15 October 2021 together with reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 10 RCTs, randomising 583 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (four trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. All the RCTs were single-centre studies. Four RCTs were conducted in the USA; two in Australia; one in China; one in Finland; one in Iran; and one in the Netherlands. The mean age of the participants ranged from 27.6 years to 49.0 years. Four trials randomised participants to nitrous oxide pneumoperitoneum (132 participants) or carbon dioxide pneumoperitoneum (128 participants). None of the trials was at low risk of bias. The evidence is very uncertain about the effects of nitrous oxide pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto odds ratio (OR) 2.62, 95% CI 0.78 to 8.85; 3 studies, 204 participants; very low-certainty evidence), or surgical morbidity (Peto OR 1.01, 95% CI 0.14 to 7.31; 3 studies, 207 participants; very low-certainty evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (4 studies, 260 participants; very low-certainty evidence). Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. The evidence is very uncertain about the effects of helium pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto OR 1.66, 95% CI 0.28 to 9.72; 3 studies, 128 participants; very low-certainty evidence), or surgical morbidity (5 studies, 177 participants; very low-certainty evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (3 studies, 128 participants; very low-certainty evidence). One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at high risk of bias. There were no cardiopulmonary complications, serious adverse events, or deaths observed related to either room air or carbon dioxide pneumoperitoneum.    AUTHORS' CONCLUSIONS: The evidence is very uncertain about the effects of nitrous oxide, helium, and room air pneumoperitoneum compared to carbon dioxide pneumoperitoneum on any of the primary outcomes, including cardiopulmonary complications, surgical morbidity, and serious adverse events. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established, especially in people with high anaesthetic risk.

Severe portal and systemic acidosis during CO2-laparoscopy compared to helium or gasless laparoscopy and laparotomy in a rodent model: an experimental study

BACKGROUND AND AIMS

This experimental study assesses the influence of different gases and insufflation pressures on the portal, central-venous and peripheral-arterial pH during experimental laparoscopy.

METHODS

Firstly, 36 male WAG/Rij rats were randomized into six groups (n = 6) spontaneously breathing during anaesthesia: laparoscopy using carbon dioxide or helium at 6 and 12 mmHg, gasless laparoscopy and laparotomy. 45 and 90 min after setup, blood was sampled from the portal vein, vena cava and the common femoral artery with immediate blood gas analysis. Secondly, 12 animals were mechanically ventilated at physiological arterial pH during 90 min of laparotomy (n = 6) or carbon dioxide laparoscopy at 12 mmHg (n = 6) with respective blood gas analyses.

RESULTS

Over time, in spontaneously breathing rats, carbon dioxide laparoscopy caused significant insufflation pressure-dependent portal acidosis (pH at 6 mmHg, 6.99 [6.95-7.04] at 45 min and 6.95 [6.94-6.96] at 90 min, pH at 12 mmHg, 6.89 [6.82-6.90] at 45 min and 6.84 [6.81-6.87] at 90 min; p < 0.05) compared to laparotomy (portal pH 7.29 [7.23-7.30] at 45 min and 7.29 [7.20-7.30] at 90 min; p > 0.05). Central-venous and peripheral-arterial acidosis was significant but less severely reduced during carbon dioxide laparoscopy. Laparotomy, helium laparoscopy and gasless laparoscopy showed no comparable acidosis in all vessels. Portal and central-venous acidosis during carbon dioxide laparoscopy at 12 mmHg was not reversible by mechanical hyperventilation maintaining a physiological arterial pH (pH portal 6.85 [6.84-6.90] (p = 0.004), central-venous 6.93 [6.90-6.99] (p = 0.004), peripheral-arterial 7.29 [7.29-7.31] (p = 0.220) at 90 min; Wilcoxon-Mann-Whitney test).

CONCLUSION

Carbon dioxide laparoscopy led to insufflation pressure-dependent severe portal and less severe central-venous acidosis not reversible by mechanical hyperventilation.

Is thoracoscopic esophageal atresia repair safe in the presence of cardiac anomalies?

BACKGROUND

Esophageal atresia (EA) is often associated with congenital heart disease (CHD). Repair of EA by the thoracoscopic approach places physiological stress on a newborn with CHD. This paper reviews the outcomes of infants with CHD who had undergone thoracoscopic EA repair, comparing their outcomes to those without CHD.

METHODS

This was a review of infants who underwent thoracoscopic EA repair from 2009 to 2017 at one institution. Operative time and outcomes were analyzed in relation to CHD status.

RESULTS

Twenty five infants underwent thoracoscopic EA repair during the study period. Seventeen (68%) had associated anomalies of whom 9 (36%) had cardiac anomalies. The mean operative time was 217 min. There was no difference in operative time between CHD and non-CHD cases (estimate 20 min longer operative time in the presence of a cardiac anomaly [95% CI -20 to 57]). Two cases were converted to open thoracotomy; both were non-CHD. There was no difference in the time to feeding, time in intensive care unit or time in hospital between CHD and non-CHD cases. Five patients developed an anastomotic leak (two CHD and three non-CHD) of which two were clinical; all were managed conservatively. There was no case of recurrent fistula.

CONCLUSIONS

This pilot study did not find evidence that thoracoscopic EA repair compromised outcomes in children with congenital heart disease. A prospective multicenter study with long-term follow-up is recommended to confirm whether thoracoscopic repair in CHD is truly equivalent to the open operation.

TYPE OF STUDY

Therapeutic.

LEVEL OF EVIDENCE

Level III.

Insufflation in minimally invasive surgery: Is there any advantage in staying low?

AIM

Minimally invasive repair of esophageal atresia with tracheoesophageal fistula (EA/TEF) and congenital diaphragmatic hernia (CDH) is feasible and confers benefits compared to thoracotomy or laparotomy. However, carbon dioxide (CO₂) insufflation can lead to hypercapnia and acidosis. We sought to determine the effect of lower insufflation pressures on patients' surrogate markers for CO₂ absorption - arterial partial pressure of CO₂ (PaCO₂), end tidal CO₂ (EtCO₂) and pH.

METHODS

Single center retrospective review, including neonates without major cardiac anomaly. Selected patients formed 2 groups: Historical pressure (HP) group and low pressure (LP) group. We reported on the patients' preoperative characteristics that potentially confound the degree of CO₂ absorption or elimination. Outcome measures were perioperative PaCO₂, EtCO₂, arterial pH and anesthetic time.

RESULTS

30 patients underwent minimally invasive surgery for CDH and 24 patients for EA/TEF with similar distribution within the HP and LP group. For CDH patients as well as for EA/TEF patients, there were no significant differences in their preoperative characteristics or surgery duration comparing HP and LP groups. With a decrease in insufflation pressure in CDH patients, there were a significant decrease (p = 0.002) in peak PaCO₂ and an improvement in nadir pH (p = 0.01). For the EA/TEF patients, the decrease in insufflation pressure was associated with a significant decrease (p = 0.03) in peak EtCO₂. Considering all 54 patients, we found EtCO₂ to be highly significantly inversely correlated with pH and positively correlated with intraoperative PaCO₂ (p < 0.001). Baseline Hb was inversely correlated with mean EtCO₂ (p < 0.001).

CONCLUSION

With lower insufflation pressures, CDH patients had significantly improved hypercapnia and acidosis, while EA/TEF patients had significantly reduced EtCO₂. EtCO₂ was correlated with acidosis and hypercapnia.

TYPE OF STUDY

Retrospective case control study.

LEVEL OF EVIDENCE

Level III.

Thoracoscopic aortopexy for symptomatic tracheobronchomalacia

AIM

Symptomatic tracheobronchomalacia can be fatal. Successful treatment includes aortopexy. We report outcomes of the thoracoscopic approach in a single centre.

METHODS

All patients undergoing thoracoscopic aortopexies from 2009 to 2018 were retrospectively reviewed. Data was reported as median (interquartile range). Risk factors for subsequent tracheostomy were analyzed with logistics regression model, p < 0.05 as significant.

RESULTS

Twenty-one patients with mid to distal tracheomalacia (n = 17) and bronchial involvement (n = 4) were determined on bronchoscopy, tracheobronchogram, or CT thorax. Preoperative patient demographics and comorbidities, e.g., gastro-oesophageal reflux disease, prematurity, and cardiac anomalies were recorded. Indications for thoracoscopic aortopexy were apparent life-threatening event(s) (n = 14), recurrent chest infections (n = 5), and failure to wean invasive ventilation (n = 2). Thoracoscopic aortopexies (n = 20) with conversion to open (n = 1) were performed. Intraoperative bleeding (n = 2) occurred, and chest tube (n = 1) was inserted for monitoring. Intraoperative bronchoscopy (n = 17) confirmed improvement of tracheomalacia. Anesthetic time was 140 (90-160) minutes. Postoperatively, 2 patients had dehiscence of the aorta from the sternum. They underwent redo open aortopexy with posterior tracheopexy, and 1 required subsequent tracheostomy. Another 2 patients required tracheostomies. Potential risk factors for subsequent tracheostomy were investigated, and only the association of tracheobronchomalacia was close to significance (OR 16 (95% CI 0.95-267.03), p = 0.05). Follow up duration was 365 (72-854) days. Symptoms resolution occurred in n = 17 (81%) of patients.

CONCLUSION

Different modalities were used to delineate the site of tracheobronchomalacia and its etiology. Tracheomalacia with bronchial involvement may be a risk factor for subsequent tracheostomy.

LEVEL OF EVIDENCE

Level 3 (Case Series).

Intraoperative acidosis and hypercapnia during thoracoscopic repair of congenital diaphragmatic hernia and esophageal atresia/tracheoesophageal fistula

BACKGROUND

Intraoperative hypercapnia and acidosis have been associated with thoracoscopic repair of both congenital diaphragmatic hernia and esophageal atresia/tracheoesophageal fistula.

AIM

The aim of the present study was to investigate whether thoracoscopic repair of congenital diaphragmatic hernia or esophageal atresia/tracheoesophageal fistula was associated with acidosis and hypercapnia in a large group of neonates, and to analyze the effects of acidosis and hypercapnia on early postoperative outcomes.

METHODS

We reviewed the charts of neonates who underwent open or thoracoscopic congenital diaphragmatic hernia or esophageal atresia/tracheoesophageal fistula repair (2004-2014). Patients with available intraoperative arterial gas values were included. Data (PaCO₂ : mm Hg) were compared using paired/unpaired tests and are reported as difference [95% confidence interval].

RESULTS

Congenital diaphragmatic hernia: 187 neonates underwent open (n=153) or thoracoscopic (n=34) repair. Intraoperative arterial gas values were recorded in 96 open and in 23 thoracoscopic operations. Both groups had similar preoperative pH and PaCO₂ , and developed intraoperative acidosis (open -0.08 [-0.11, -0.05] P<.001, thoracoscopic -0.14 [-0.24, -0.04] P=.01) and hypercapnia (open: 7.8 [3.2, 12.4], P=.002; thoracoscopic: 20.2 [-2.5, 43, P=.07). Intraoperatively, neonates undergoing thoracoscopic repair developed lower pH than those having open surgery (-0.06 [-0.01, -0.10] P=.018), but maintained similar levels of PaCO₂ (-4.0 [-9.0, 4.4] P=.39). Esophageal atresia/tracheoesophageal fistula: 205 neonates underwent open (n=180) or thoracoscopic (n=25) repair. Intraoperative arterial gas values were recorded in 62 open and in 14 thoracoscopic operations. Both groups had similar preoperative pH and PaCO₂ , and developed intraoperative acidosis (open: -0.09 [-0.14, -0.04], P<.001; thoracoscopic: 0.21 [-0.28, -0.14], P<.001) and hypercapnia (open: 9.2 [2.6, 15.7] P=.008; thoracoscopic: 15.2 [1.6, 28.7], P=.03). Intraoperatively, neonates undergoing thoracoscopic repair developed lower pH than those having open surgery (difference 0.08 [0.01, 0.15], P=.02) but maintained similar levels of PaCO₂ (difference -1 [-9, 3], P=.35).

CONCLUSION

Neonates undergoing operative repair of congenital diaphragmatic hernia and esophageal atresia/tracheoesophageal fistula develop intraoperative acidosis and hypercapnia, regardless of the approach used. However, this phenomenon is more severe during thoracoscopic repair. Novel modalities to reduce intraoperative gas derangements, particularly during thoracoscopic repair, need to be established.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery

BACKGROUND

This is an update of the review published in 2013.Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. People with high anaesthetic risk are more likely to experience cardiopulmonary complications and adverse events, for example hypercapnia and acidosis, which has to be avoided by hyperventilation. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum.

OBJECTIVES

To assess the safety, benefits, and harms of different gases (i.e. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic general abdominal or gynaecological pelvic surgery.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2016, Issue 9), Ovid MEDLINE (1950 to September 2016), Ovid Embase (1974 to September 2016), Science Citation Index Expanded (1970 to September 2016), Chinese Biomedical Literature Database (CBM) (1978 to September 2016), ClinicalTrials.gov (September 2016), and World Health Organization International Clinical Trials Registry Platform (September 2016).

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors identified the trials for inclusion, collected the data, and assessed the risk of bias independently. We performed the meta-analyses using Review Manager 5. We calculated risk ratio (RR) for dichotomous outcomes (or Peto odds ratio for very rare outcomes), and mean difference (MD) or standardised mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI). We used GRADE to rate the quality of evidence, MAIN RESULTS: We included nine RCTs, randomising 519 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (three trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. Three trials randomised participants to nitrous oxide pneumoperitoneum (100 participants) or carbon dioxide pneumoperitoneum (96 participants). None of the trials was at low risk of bias. There was insufficient evidence to determine the effects of nitrous oxide and carbon dioxide on cardiopulmonary complications (RR 2.00, 95% CI 0.38 to 10.43; two studies; 140 participants; very low quality of evidence), or surgical morbidity (RR 1.01, 95% CI 0.18 to 5.71; two studies; 143 participants; very low quality of evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (three studies; 196 participants; very low quality of evidence). We could not combine data from two trials (140 participants) which individually showed lower pain scores (a difference of about one visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain) with nitrous oxide pneumoperitoneum at various time points on the first postoperative day, and this was rated asvery low quality .Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. There was insufficient evidence to determine the effects of helium or carbon dioxide on cardiopulmonary complications (RR 1.46, 95% CI 0.35 to 6.12; three studies; 128 participants; very low quality of evidence) or pain scores (visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain; MD 0.49 cm, 95% CI -0.28 to 1.26; two studies; 108 participants; very low quality of evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (three studies; 128 participants; very low quality of evidence).One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at unclear risk of bias. There were no cardiopulmonary complications or serious adverse events observed related to either room air or carbon dioxide pneumoperitoneum (both outcomes very low quality of evidence). The evidence of lower hospital costs and reduced pain during the first postoperative day with room air pneumoperitoneum compared with carbon dioxide pneumoperitoneum (a difference of about one visual analogue score on a scale of 1 to 10 with lower numbers indicating less pain, was rated as very low quality of evidence.

AUTHORS' CONCLUSIONS

The quality of the current evidence is very low. The effects of nitrous oxide and helium pneumoperitoneum compared with carbon dioxide pneumoperitoneum are uncertain. Evidence from one trial of small sample size suggests that room air pneumoperitoneum may decrease hospital costs in people undergoing laparoscopic abdominal surgery. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established.Further trials on this topic are needed, and should compare various gases (i.e. nitrous oxide, helium, argon, nitrogen, and room air) with carbon dioxide under standard pressure pneumoperitoneum with cold gas insufflation for people with high anaesthetic risk. Future trials should include outcomes such as complications, serious adverse events, quality of life, and pain.

The first 100 infant thoracoscopic lobectomies: Observations through the learning curve and comparison to open lobectomy

OBJECTIVE

The objective of the study is to describe our initial 100 attempted infant thoracoscopic lobectomies for asymptomatic, prenatally diagnosed lung lesions, and compare the results to contemporaneous age-matched patients undergoing open lobectomy.

BACKGROUND

Infant thoracoscopic lobectomy is a technically challenging procedure, which has only gained acceptance worldwide in recent years.

METHODS

This is a retrospective review of all patients undergoing thoracoscopic or open lung lobectomy between March 2005 and January 2014. Included were all asymptomatic infants younger than 4months. Excluded were patients undergoing emergent lobectomy and patients with isolated extralobar bronchopulmonary sequestrations.

RESULTS

A total of 100 attempted thoracoscopic lobectomies were compared with 188 open lobectomies. In the thoracoscopic group, mean age and weight at surgery were 7.3weeks and 4.8kg, mean operative time was 185minutes, and mean hospital stay was 3days. Twelve cases were converted to open (12%). Ten conversions occurred within the first third of the series and none in the last third. There were no mortalities. There were no differences between the thoracoscopic and open groups in perioperative complications or hospital stay. There was a significant difference in the operative time: 111minutes vs. 185minutes (open vs. thoracoscopic; p<0.001). There was a higher mean end-tidal carbon dioxide (ETCO2) and lower mean peripheral capillary oxygen saturation (SpO2) in the thoracoscopic group versus the open group (51.7 versus 38.6mmHg and 97.5 versus 99.1%, respectively).

CONCLUSION

In high volume centers, the learning curve of thoracoscopic lobectomy can be overcome and the procedure can be performed with equivalent outcomes and, in our opinion, superior cosmetic results to open lobectomy.

Hypercapnia and acidosis during the thoracoscopic repair of oesophageal atresia and congenital diaphragmatic hernia

Thoracoscopic operations in neonates, such as repair of oesophageal atresia and tracheooesophageal fistula or congenital diaphragmatic hernia, can be associated with intraoperative acidosis and hypercapnia in the absence of hypoxia. These derangements in intraoperative gas exchanges seem to be related to the insufflation and absorption of medical CO2. The effects on the developing brain are unknown, and further prospective investigations are needed to elucidate whether different strategies should be implemented to avoid these intraoperative problems.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery

BACKGROUND

Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Many other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum.

OBJECTIVES

To assess the safety, benefits, and harms of different gases for establishing pneumoperitoneum in patients undergoing laparoscopic abdominal surgery.

SEARCH METHODS

We searched The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, and Chinese Biomedical Literature Database (CBM) until September 2012.

SELECTION CRITERIA

We only included randomized controlled trials comparing different gases for establishing pneumoperitoneum in patients undergoing laparoscopic abdominal surgery under general anaesthesia.

DATA COLLECTION AND ANALYSIS

Two review authors identified the trials for inclusion, collected the data, and assessed the risk of bias independently. We performed the meta-analyses using Review Manager 5. We calculated the risk ratio (RR) for dichotomous outcomes and the mean difference (MD) or standardized mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI).

MAIN RESULTS

Carbon dioxide pneumoperitoneum versus nitrous oxide pneumoperitoneum Three trials randomized 196 participants (the majority with low anaesthetic risk) to carbon dioxide pneumoperitoneum (n =96) or nitrous oxide pneumoperitoneum (n =100). All of the trials were of high risk of bias. Two trials (n=143) showed lower pain scores in nitrous oxide pneumoperitoneum at various time points on the first post-operative day. One trial (n=53) showed no difference in the pain scores between the groups. There were no significant differences in cardiopulmonary complications, surgical morbidity, or cardiopulmonary changes between the groups. There were no serious adverse events related to either carbon dioxide or nitrous oxide pneumoperitoneum. Carbon dioxide pneumoperitoneum versus helium pneumoperitoneum Four trials randomized 144 participants (the majority with low anaesthetic risk) to carbon dioxide pneumoperitoneum (n =75) or helium pneumoperitoneum (n =69). All of the trials were of high risk of bias. Fewer cardiopulmonary changes were observed with helium pneumoperitoneum than carbon dioxide pneumoperitoneum. There were no significant differences in cardiopulmonary complications, surgical morbidity, or pain scores. There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum. Carbon dioxide pneumoperitoneum versus any other gas pneumoperitoneum There were no randomized controlled trials comparing carbon dioxide pneumoperitoneum to any other gas pneumoperitoneum.

AUTHORS' CONCLUSIONS

1. Nitrous oxide pneumoperitoneum during laparoscopic abdominal surgery appears to decrease post-operative pain in patients with low anaesthetic risk.2. Helium pneumoperitoneum decreases the cardiopulmonary changes associated with laparoscopic abdominal surgery. However, this did not translate into any clinical benefit over carbon dioxide pneumoperitoneum in patients with low anaesthetic risk.3. The safety of nitrous oxide and helium pneumoperitoneum has yet to be established. More randomized controlled trials on this topic are needed. Future trials should include more patients with high anaesthetic risk. Furthermore, such trials need to use adequate methods to reduce the risk of bias.