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Introduction: Per-oral endoscopic myotomy (POEM) is an effective modality for the management of achalasia. Tension pneumoperitoneum is a significant complication that causes hemodynamic instability, generally within the periprocedural period., Methods: Here, we report 2 cases of delayed tension pneumoperitoneum that was recognized and treated several hours after uncomplicated POEM., Results: These cases illustrate the importance of continued vigilance for this complication outside of the immediate periprocedural period as well as the utility of computed tomography-guided aspiration in managing it., Discussion: When discharging patients after POEM, caregivers should be aware of this rare complication and alert patients to return for immediate care when it happens., (Copyright © 2020 by The American College of Gastroenterology.)

We hypothesized that deep neuromuscular blockade (NMB) with low-pressure pneumoperitoneum (PP) would improve respiratory mechanics and reduce biotrauma compared to moderate NMB with high-pressure PP in a steep Trendelenburg position. Seventy-four women undergoing robotic gynecologic surgery were randomly assigned to two equal groups. Moderate NMB group was maintained with a train of four count of 1-2 and PP at 12 mmHg. Deep NMB group was maintained with a post-tetanic count of 1-2 and PP at 8 mmHg. Inflammatory cytokines were measured at baseline, at the end of PP, and 24 h after surgery. Interleukin-6 increased significantly from baseline at the end of PP and 24 h after the surgery in moderate NMB group but not in deep NMB group (P group*time  = 0.036). The peak inspiratory, driving, and mean airway pressures were significantly higher in moderate NMB group than in deep NMB group at 15 min and 60 min after PP (P group*time  = 0.002, 0.003, and 0.048, respectively). In conclusion, deep NMB with low-pressure PP significantly suppressed the increase in interleukin-6 developed after PP, by significantly improving the respiratory mechanics compared to moderate NMB with high-pressure PP during robotic surgery.

Background: Laparoscopic surgeries are a risk factor for raised intracranial **pressure and neurological complications. Even though rare, the consequences may be severe., Methods: One hundred and one patients of laparoscopic cholecystectomy were enrolled and were randomized into two groups: low-pressure 8 mm Hg (Group A) and high-pressure 14 mm Hg (Group B) carbon dioxide pneumoperitoneum during surgery. Fifty patients were in group A and 51 patients were in group B. Intracranial pressure was measured by measuring the optic nerve sheath diameter (ONSD) using ultrasound examination. Baseline ONSD was recorded followed by ONSD recording at various intervals: at the induction of anesthesia; 30 min, 45 min, at the end of surgery; and 30 min post surgery., Results: The groups were comparable in terms of demographics and comorbidities. The mean age of group A was 45 years and for group B it was 45.75 years. Most common indication for surgery was symptomatic gall stone disease. Baseline ONSD in group A was 0.427 ± 0.0459 mm, whereas it was 0.412 ± 0.0412 mm in group B. There was a significant rise of ONSD (p < 0.05) 30 min after induction of pneumoperitoneum and up to 30 min post anesthesia. In the low-pressure group 7 (14%) patients had a significant rise of ICP, whereas in the high-pressure group 20 (39%) patients had a significant rise of ICP (p < 0.05)., Conclusions: High-pressure pneumoperitoneum causes significant rise in intracranial pressure in comparison to low-pressure pneumoperitoneum during laparoscopic cholecystectomy, which can be monitored by ONSD measurement by ultrasound examination and is totally non-invasive.

Objective: To compare changes in microcirculation blood flow (MCBF) between pulsatile and continuous flow insufflation. Transanal total mesorectal excision (TaTME) was developed to improve the quality of the resection in rectal cancer surgery. The AirSeal IFS® insufflator facilitates the pelvic dissection, although evidence on the effects that continuous flow insufflation has on MCBF is scarce., Methods: Thirty-two pigs were randomly assigned to undergo a two-team TaTME procedure with continuous (n = 16) or pulsatile insufflation (n = 16). Each group was stratified according to two different pressure levels in both the abdominal and the transanal fields, 10 mmHg or 14 mmHg. A generalized estimating equations (GEE) model was used., Results: At an intra-abdominal pressure (IAP) of 10 mmHg, continuous insufflation was associated with a significantly lower MCBF reduction in colon mucosa [13% (IQR 11;14) vs. 21% (IQR 17;24) at 60 min], colon serosa [14% (IQR 9.2;18) vs. 25% (IQR 22;30) at 60 min], jejunal mucosa [13% (IQR 11;14) vs. 20% (IQR 20;22) at 60 min], renal cortex [18% (IQR 15;20) vs. 26% (IQR 26;29) at 60 min], and renal medulla [15% (IQR 11;20) vs. 20% (IQR 19;21) at 90 min]. At an IAP of 14 mmHg, MCBF in colon mucosa decreased 23% (IQR 14;27) in the continuous group and 28% (IQR 26;31) in the pulsatile group (p = 0.034)., Conclusion: TaTME using continuous flow insufflation was associated with a lower MCBF reduction in colon mucosa and serosa, jejunal mucosa, renal cortex, and renal medulla compared to pulsatile insufflation.

Background: Capnoperitoneum during laparoscopy leads to cranial shift of the diaphragm, loss in lung volume, and risk of impaired gas exchange. Infants are susceptible to these changes and bedside assessment of lung volume during laparoscopy might assist with optimizing the ventilation. Thus, the primary aim was to investigate the monitoring value of a continuous end-expiratory lung volume (EELV) assessment method based on CO 2 dynamics ( EELV CO 2 ) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELV He )., Methods: Intra-abdominal pressure (IAP) was randomly varied between 0, 6, and 12 mm Hg with CO 2 insufflation, while positive end-expiratory pressure (PEEP) levels of 3, 6, and 9 cm H 2 O were randomly applied in eight anesthetized and mechanically ventilated chinchilla rabbits. Concomitant EELV CO 2 and EELV He and lung clearance index (LCI) were obtained under each experimental condition., Results: Significant correlations were found between EELV CO 2 and EELV He before capnoperitoneum (r = .85, P < .001), although increased IAP distorted this relationship. The negative influence of IAP was counteracted by the application of PEEP 9, which restored the correlation between EELV CO 2 and EELV He and resulted in 100% concordance rate between the methods regarding changes in lung volume. EELV He and LCI showed a curvilinear relationship, and an EELV He of approximately 20 mL kg -1 , determined with a receiver operating characteristic curve, was associated with near-normal LCI values., Conclusion: In this animal model of pediatric capnoperitoneum, reliable assessment of changes in EELV based on EELV CO 2 requires an open lung strategy, defined as EELV above approximately 20 mL kg -1 ., (© 2020 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.)

Postoperative cognitive dysfunction (POCD) is a common complication after surgery, especially in aged patients. Neuroinflammation has been closely associated with the development of POCD. While the contribution of pneumoperitoneum to the systemic inflammation has been well documented, the effect of pneumoperitoneal pressure on neuroinflammation and postoperative cognitive function remains unclear. In this study, we showed that high-pressure pneumoperitoneum promoted the postoperative neuroinflammation and microglial activation in the hippocampus and aggravated the postoperative cognitive impairment in aged mice. These results support the requirement to implement interventions with lower intra-abdominal pressure, which allows for adequate exposure of the operative field rather than a routine pressure., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Bo Lu et al.)

Background: Pneumoperitoneum for laparoscopic surgery is associated with a rise of driving pressure. The authors aimed to assess the effects of positive end-expiratory pressure (PEEP) on driving pressure at varying intraabdominal pressure levels. It was hypothesized that PEEP attenuates pneumoperitoneum-related rises in driving pressure., Methods: Open-label, nonrandomized, crossover, clinical trial in patients undergoing laparoscopic cholecystectomy. "Targeted PEEP" (2 cm H2O above intraabdominal pressure) was compared with "standard PEEP" (5 cm H2O), with respect to the transpulmonary and respiratory system driving pressure at three predefined intraabdominal pressure levels, and each patient was ventilated with two levels of PEEP at the three intraabdominal pressure levels in the same sequence. The primary outcome was the difference in transpulmonary driving pressure between targeted PEEP and standard PEEP at the three levels of intraabdominal pressure., Results: Thirty patients were included and analyzed. Targeted PEEP was 10, 14, and 17 cm H2O at intraabdominal pressure of 8, 12, and 15 mmHg, respectively. Compared to standard PEEP, targeted PEEP resulted in lower median transpulmonary driving pressure at intraabdominal pressure of 8 mmHg (7 [5 to 8] vs. 9 [7 to 11] cm H2O; P = 0.010; difference 2 [95% CI 0.5 to 4 cm H2O]); 12 mmHg (7 [4 to 9] vs.10 [7 to 12] cm H2O; P = 0.002; difference 3 [1 to 5] cm H2O); and 15 mmHg (7 [6 to 9] vs.12 [8 to 15] cm H2O; P < 0.001; difference 4 [2 to 6] cm H2O). The effects of targeted PEEP compared to standard PEEP on respiratory system driving pressure were comparable to the effects on transpulmonary driving pressure, though respiratory system driving pressure was higher than transpulmonary driving pressure at all intraabdominal pressure levels., Conclusions: Transpulmonary driving pressure rises with an increase in intraabdominal pressure, an effect that can be counterbalanced by targeted PEEP. Future studies have to elucidate which combination of PEEP and intraabdominal pressure is best in term of clinical outcomes.

Background: Airway closure causes lack of communication between proximal airways and alveoli, making tidal inflation start only after a critical airway opening pressure is overcome. The authors conducted a matched cohort study to report the existence of this phenomenon among obese patients undergoing general anesthesia., Methods: Within the procedures of a clinical trial during gynecological surgery, obese patients underwent respiratory/lung mechanics and lung volume assessment both before and after pneumoperitoneum, in the supine and Trendelenburg positions, respectively. Among patients included in this study, those exhibiting airway closure were compared to a control group of subjects enrolled in the same trial and matched in 1:1 ratio according to body mass index., Results: Eleven of 50 patients (22%) showed airway closure after intubation, with a median (interquartile range) airway opening pressure of 9 cm H2O (6 to 12). With pneumoperitoneum, airway opening pressure increased up to 21 cm H2O (19 to 28) and end-expiratory lung volume remained unchanged (1,294 ml [1,154 to 1,363] vs. 1,160 ml [1,118 to 1,256], P = 0.155), because end-expiratory alveolar pressure increased consistently with airway opening pressure and counterbalanced pneumoperitoneum-induced increases in end-expiratory esophageal pressure (16 cm H2O [15 to 19] vs. 27 cm H2O [23 to 30], P = 0.005). Conversely, matched control subjects experienced a statistically significant greater reduction in end-expiratory lung volume due to pneumoperitoneum (1,113 ml [1,040 to 1,577] vs. 1,000 ml [821 to 1,061], P = 0.006). With airway closure, static/dynamic mechanics failed to measure actual lung/respiratory mechanics. When patients with airway closure underwent pressure-controlled ventilation, no tidal volume was inflated until inspiratory pressure overcame airway opening pressure., Conclusions: In obese patients, complete airway closure is frequent during anesthesia and is worsened by Trendelenburg pneumoperitoneum, which increases airway opening pressure and alveolar pressure: besides preventing alveolar derecruitment, this yields misinterpretation of respiratory mechanics and generates a pressure threshold to inflate the lung that can reach high values, spreading concerns on the safety of pressure-controlled modes in this setting.

Objective: Pneumoperitoneum and the head-up position reportedly stimulate the sympathetic nervous system, potentially increasing the risk of cardiac arrhythmia. We evaluated the effects of a long duration of pneumoperitoneum in the head-up position on the heart rate-corrected QT (QTc) interval during robotic gastrectomy., Methods: This prospective observational study involved 28 patients undergoing robotic gastrectomy. The QTc interval was recorded at the following time points: before anaesthetic induction (baseline); 10 minutes after tracheal intubation; 1, 5, 30, 60, and 90 minutes after pneumoperitoneum induction in the head-up position; after pneumoperitoneum desufflation in the supine position; and at the end of surgery. The primary outcome was the QTc interval, which was measured 90 minutes after pneumoperitoneum combined with the head-up position., Results: Compared with baseline, the QTc interval was significantly prolonged at 1 and 60 minutes after pneumoperitoneum, peaked at 90 minutes, and was sustained and notably prolonged until the end of surgery. However, no considerable haemodynamic changes developed., Conclusion: A long period of carbon dioxide pneumoperitoneum application in a head-up position significantly prolonged the QTc interval during robotic gastrectomy. Therefore, diligent care and close monitoring are required for patients who are susceptible to developing ventricular arrhythmia. Trial Registration: Registered at ClinicalTrials.gov; https://clinicaltrials.gov/ct2/show/NCT02604979 ; Registration number NCT02604979.

Animal studies suggest that dynamic predictors remain useful in patients with pneumoperitoneum, but human data is conflicting. Our aim was to determine predictive values of pulse pressure variation (PPV) and stroke volume variation (SVV) in patients with pneumoperitoneum using LiDCORapid™ haemodynamic monitor. Standardised fluid challenges of colloid were administered to patients undergoing laparoscopic procedures, one fluid challenge per patient. Intra-abdominal pressure was automatically held at 12 mmHg. Fluid responsiveness was defined as an increase in nominal stroke index (nSI) ≥ 10%. Linear regression was used to assess the ability of PPV and SVV to track the changes of nSI and logistic regression and area under the receiver operating curve (AUROC) to assess the predictive value of PPV and SVV for fluid responsiveness. Threshold values for PPV and SVV were obtained using the "gray zone" approach. A p < 0.05 was considered as statistically significant. 56 patients were included in analysis. 41 patients (73%) responded to fluids. Both PPV and SVV tracked changes in nSI (Spearman correlation coefficients 0.34 for PPV and 0.53 for SVV). Odds ratio for fluid responsiveness for PPV was 1.163 (95% CI 1.01-1.34) and for SVV 1.341 (95% CI 1.10-1.63). PPV achieved an AUROC of 0.674 (95% CI 0.518-0.830) and SVV 0.80 (95% CI 0.668-0.932). The gray zone of PPV ranged between 6.5 and 20.5% and that of SVV between 7.5 and 13%. During pneumoperitoneum, as measured by LiDCORapid™, PPV and SVV can predict fluid responsiveness, however their sensitivity is lower than the one reported in conditions without pneumoperitoneum. Trial registry number: (with the Australian New Zealand Clinical Trials Registry): ACTRN12612000456853.

Simultaneous pneumoperitoneum and pneumomediastinum is a rare clinical occurrence. It has been reported in the literature as a complication of various medical and dental procedures. To our knowledge, we present the first case of a non-iatrogenic and traumatic simultaneous pneumoperitoneum and pneumomediastinum in a previously independent 91-year-old man who presented to hospital with back and chest wall pain following mechanical fall from standing. A new radiological diagnosis of diverticular disease with possible perforation was made following admission. Despite appropriate management and supportive measures, the patient died 12 days after admission from a kidney injury.

Background: Although air has traditionally been considered a barrier to sonographic imaging, when encountered in unusual settings it can serve as an important indicator of various pathologic states as well. Clinician recognition and thorough understanding of the characteristic pattern of artifacts generated by air are critical for making a number of important diagnoses., Case Series: We present five emergency department cases in which air was visualized in a pathologic location. Pneumothorax, pneumoperitoneum, necrotizing fasciitis, or Fournier's gangrene, and subcutaneous emphysema and pneumomediastinum, can be rapidly and easily identified on ultrasound by the presence of air artifacts. The relevant sonographic findings are described and discussed in this article. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Due to its inherent impedance mismatch with other human tissues, air has a characteristic appearance on ultrasound that includes irregular hyperechoic structures, "dirty shadowing," A-lines, and decreased visualization of deeper structures. Knowledge of the sonographic appearance of air artifacts can assist the physician in making a diagnosis, selecting appropriate additional imaging, and enlisting specialist consultation., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Each different gas that is used to induce a pneumoperitoneum (PP) exhibits individual effects within the peritoneal cavity. This might include adverse effects such as pain and/or inflammatory reactions. The acute effects of ozonized oxygen (O 3 /O 2 ), a highly oxidative gas mixture, after being insufflated into the peritoneal cavity are analysed in this study. Using the abdominal constriction response ('writhing') assay of chemical nociception in C57BL6/N mice, O 3 /O 2 -PP was found not to be associated with visible pain responses and did not alter the c-fos expression in the spinal cord. In addition, mRNA expression levels of the pro-inflammatory cytokines, interleukin (IL)-1β and IL-6, were found unaltered in the spleen 2 h after insufflation. In conclusion, O 3 /O 2 -PP is free of adverse pain and does not trigger inflammatory immune responses.

Objective: A pulmonary recruitment maneuver (PRM) can effectively reduce post-laparoscopic shoulder pain (PLSP). However, a high-pressure PRM may cause pulmonary barotrauma. This study aimed to evaluate the efficacy and safety of a PRM using two different maximum inspiratory pressures (40 and 60cmH 2 O) for reducing PLSP., Study Design: Patients undergoing gynecologic laparoscopy were randomly allocated to a control group (n=30), a 40 cmH 2 O PRM group (n=30), and a 60 cmH 2 O PRM group (n=30). In the control group, residual carbon dioxide was removed by passive exsufflation through the port site. In the two intervention groups, the PRM consisting of five manual pulmonary inflations was performed at the end of surgery with a maximum pressure of 40 cmH 2 O or 60 cmH 2 O, respectively. Shoulder pain and wound pain were recorded using a visual analogue scale at 24 and 48h postoperatively., Results: Wound pain scores at 24 and 48h post-surgery were not different between the three groups. The PLSP scores in the two intervention groups were significantly lower than that seen in the control group at 24 and 48h postoperatively (P=0.006 and P<0.001, respectively). However, there were no statistically significant differences in the PLSP scores between the two intervention groups., Conclusion: A low-pressure PRM (40cmH 2 O) is as effective as a high-pressure PRM (60cmH 2 O) for removing residual gas from the peritoneal cavity. PRM using a maximal inspiratory pressure of 40cmH 2 O is safe and efficacious for the reduction of PLSP., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Background: The laparoscopic approach is becoming increasingly frequent for many different surgical procedures. However, the combination of pneumoperitoneum and Trendelenburg positioning associated with this approach may increase the patient's risk for elevated intracranial pressure (ICP). Given that the gold standard for the measurement of ICP is invasive, little is known about the effect of these common procedures on ICP., Methods: We prospectively studied 40 patients without any history of cerebral disease who were undergoing laparoscopic procedures. Three different methods were used for non-invasive estimation of ICP: ultrasonography of the optic nerve sheath diameter (ONSD); transcranial Doppler-based (TCD) pulsatility index (ICP PI ); and a method based on the diastolic component of the TCD cerebral blood flow velocity (ICP FVd ). The ONSD and TCD were measured immediately after induction of general anaesthesia, after pneumoperitoneum insufflation, after Trendelenburg positioning, and again at the end of the procedure., Results: The ONSD, ICP FVd , and ICP PI increased significantly after the combination of pneumoperitoneum insufflation and Trendelenburg positioning. The ICP FVd showed an area under the curve of 0.80 [95% confidence interval (CI) 0.70-0.90] to distinguish the stage associated with the application of pneumoperitoneum and Trendelenburg position; ONSD and ICP PI showed an area under the curve of 0.75 (95% CI 0.65-0.86) and 0.70 (95% CI 0.58-0.81), respectively., Conclusions: The concomitance of pneumoperitoneum and the Trendelenburg position can increase ICP as estimated with non-invasive methods. In high-risk patients undergoing laparoscopic procedures, non-invasive ICP monitoring through a combination of ONSD ultrasonography and TCD-derived ICP FVd could be a valid option to assess the risk of increased ICP., (© The Author 2016. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Non-invasive measurement of ICP (nICP) can be warranted in patients at risk for developing increased ICP during pneumoperitoneum (PP). Our aim was to assess available data on the application of nICP monitoring during these procedures and to present a patient assessed with an innovative combination of noninvasive tools. Literature review of nICP assessment during PP did not find any studies comparing different methods intraprocedurally and only few studies of any nICP monitoring were available: transcranial Doppler (TCD) studies used the pulsatility index (PI) as an estimator of ICP and failed to detect a significant ICP increase during PP, whereas two out of three optic nerve sheath diameter (ONSD) studies detected a statistically significant ICP increase. In the case study, we describe a 52 year old man with a high grade thalamic glioma who underwent urgent laparoscopic cholecystectomy. Considering the high intraoperative risk of developing intracranial hypertension, he was monitored through parallel ONSD ultrasound measurement and TCD derived formulae (flow velocity diastolic formula, FVdnICP, and PI). ONSD and FVdnICP methods indicated a significant ICP increase during PP, whereas PI was not significantly increased. Our experience, combined with the literature review, seems to suggest that PI might not detect ICP changes in this context, however we indicate a possible interest of nICP monitoring during PP by means of ONSD and of TCD derived FVdNICP, especially for patients at risk for increased ICP.

Background: Pneumomediastinum is the presence of free air around mediastinal structures, which may be spontaneous or secondary, and can occur in 10% of patients with blunt chest trauma, with the Macklin effect being its main pathophysiology., Clinical Case: A 21 year old male, hit by motor vehicle, with alvéolopalatal fracture and blunt chest trauma, who, 72 hrs after admission, shows subcutaneous emphysema in the anterior chest. A simple tomography of the chest and abdomen was performed, finding a pneumomediastinum, bilateral pulmonary contusions and pneumoperitoneum. Oesophageal, tracheobronchial or intra-abdominal viscera injuries were ruled out, establishing the cause of pneumomediastinum and pneumoperitoneum due to the Macklin effect. This required conservative management in intensive care unit, with a favourable clinical course and discharged after a 10 day hospital stay., Discussion: Macklin effect is caused by dissection of air medially along the bronchoalveolar sheath (interstitial emphysema), secondary to alveolar breakdown and extending into mediastinal and other anatomical structures (pneumoperitoneum). It has been documented in blunt trauma, as well as in acute asthma, positive pressure ventilation, or after Valsalva manoeuvres. The imaging method of choice is computed tomography, and its characteristic findings, interstitial emphysema adhering to a bronchus and pulmonary blood vessel., Conclusions: In the presence of pneumomediastinum and pneumoperitoneum is necessary to rule out oesophageal and tracheobronchial injury before establishing the Macklin effect as its cause. The diagnosis is made with computed tomography and managed conservatively., (Copyright © 2015 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.)

Background: Increased intra-abdominal pressure and hemodynamic variations during hyperthermic intraperitoneal chemotherapy (HIPEC) are expected to be comparable to pneumoperitoneum with decreased Cardiac Index (CI) and increased Systemic Vascular Resistance Index (SVRI). We hypothesized that despite comparable increased intra-abdominal pressure, hemodynamic changes during HIPEC would substantially differ from those described in laparoscopic surgery., Methods: In this prospective observational clinical study, after obtaining written informed consent, we assessed intra-abdominal pressure and hemodynamic and respiratory changes during HIPEC in 10 consecutive patients. Intra-abdominal pressure as the primary endpoint was continuously measured with a catheter placed in the abdominal cavity. Secondary endpoints were hemodynamic changes measured by pulse contour analysis and respiratory alterations. Fluid management was based on stroke volume variation., Results: The mean intra-abdominal pressure was constantly elevated during HIPEC at a level of 14.2 mmHg (P=0.002 compared to baseline). The mean SVRI dropped from 1716 dyn*sec/cm³/m² to 1490 dyn*sec/cm⁵/m² at the end of HIPEC (P<0.05). Mean CI increased from 3.2 to 3.45 L/m² (P<0.001) and Horovitz index decreased from 548 to 380 (P=0.001). Median fluid intake was 7000 mL. No patient developed acute kidney injury., Conclusions: Increased intra-abdominal pressure during HIPEC was comparable to pneumoperitoneum. Hemodynamic changes however were opposed with a decrease in SVRI and a compensative increase in CI. Current guidelines for anesthetic management in patients undergoing HIPEC are mainly based on findings from laparoscopic surgery and should therefore be reconsidered critically.

Background: The FloTrac/Vigileo™ system does not thoroughly reflect variable arterial tones, due to a lack of external calibration. The ability of this system to measure stroke volume and track its changes after fluid administration has not been fully evaluated in patients with the high systemic vascular resistance that can develop during laparoscopic surgery., Methods: In 42 patients undergoing laparoscopic prostatectomy, the stroke volume derived by the third-generation FloTrac/Vigileo™ system (SV-Vigileo), the stroke volume measured using transesophageal echocardiography (SV-TEE) as a reference method, and total systemic vascular resistance were evaluated before and after 500 ml fluid administration during pneumoperitoneum combined with the Trendelenburg position., Results: Total systemic vascular resistance was 2159.4 ± 523.5 dyn·s/cm5 before fluid administration. The SV-Vigileo was significantly higher than the SV-TEE both before (68.8 ± 15.9 vs. 57.0 ± 11.0 ml, P < 0.001) and after (73.0 ± 14.8 vs. 64.9 ± 12.2 ml, P = 0.003) fluid administration. During pneumoperitoneum combined with the Trendelenburg position, Bland-Altman analysis for repeated measures showed a 53.8% of percentage error between the SV-Vigileo and the SV-TEE. Four-quadrant plot (69.2% of a concordance rate) and polar plot analysis (20.6° of a mean polar angle, 16.4° of the SD of a polar angle, and ±51.5° of a radial sector containing 95% of the data points) did not indicate a good trending ability of the FloTrac/Vigileo™ system., Conclusions: The third-generation FloTrac/Vigileo™ system may not be useful in patients undergoing laparoscopic surgery, based on unreliable performance in measuring the stroke volume and in tracking changes in the stroke volume after fluid administration during pneumoperitoneum combined with the Trendelenburg position.

Background: Pneumoperitoneum is defined as the existence of extraluminal air in the abdominal cavity. In 80-90% of cases is due to perforation of a hollow organ. However, in 10-15% of cases, it is nonsurgical pneumoperitoneum., Objective: The case of a patient undergoing mechanical ventilation, developing abdominal compartment syndrome tension pneumoperitoneum is reported., Clinical Case: Female, 75 years old asking for advise due to flu of long term duration. Given her respiratory instability, admission to the Intensive Care Unit is decided. It is then intubated and mechanically ventilated. Chest x-ray revealed a large pneumoperitoneum but no pneumothorax neither mediastinum; and due to the suspicion of viscera perforation with clinical instability secondary to intra-abdominal hypertension box, emergency surgery was decided., Conclusions: When discarded medical history as a cause of pneumoperitoneum, it is considered that ventilation is the most common cause. Benign idiopathic or nonsurgical pneumoperitoneum, can be be treated conservatively if the patient agrees. But if intraabdominal hypertension prevails, it can result in severe respiratory and hemodynamic deterioration, sometimes requiring abdominal decompression to immediately get lower abdominal pressure and thus improve hemodynamic function., (Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.)

Objective: To compare the effects of pneumoperitoneum on lung mechanics, end-tidal CO2 (ETCO2), arterial blood gases (ABG), and oxidative stress markers in blood and bronchoalveolar lavage fluid (BALF) during laparoscopic cholecystectomy (LC) by using lung-protective ventilation strategy., Materials and Methods: Forty-six patients undergoing LC and abdominal wall hernia (AWH) surgery were assigned into 2 groups. Measurements and blood samples were obtained before, during pneumoperitoneum, and at the end of surgery. BALF samples were obtained after anesthesia induction and at the end of surgery., Results: Peak inspiratory pressure, ETCO2, and pCO2 values at the 30th minute were significantly increased, while there was a significant decrease in dynamic lung compliance, pH, and pO2 values in LC group. In BALF samples, total oxidant status (TOS), arylesterase, paraoxonase, and malondialdehyde levels were significantly increased; the glutathione peroxidase levels were significantly decreased in LC group. The serum levels of TOS and paraoxonase were significantly higher at the end of surgery in LC group. In addition, arylesterase level in the 30th minute was increased compared to baseline. Serum paraoxonase level at the end of surgery was significantly increased when compared to AWH group., Conclusions: Our study showed negative effects of pneumoperitoneum in both lung and systemic levels despite lung-protective ventilation strategy.

Objective: Increased pneumoperitoneum pressure during laparoscopic surgery can result in acute kidney injury. We aimed to clarify whether intraabdominal pressure tolerance is modified in various degrees of unilateral kidney hydronephrosis in rabbits., Methods: A total 90 rabbits were randomly allocated to three groups (group PN, PM and PS, i.e. rabbits with no, mild and severe hydronephrosis, respectively, subjected to intraabdominal pressures). Rabbits in group PM (n=30) and group PS (n=30) underwent a surgical procedure inducing a mild or severe left hydronephrosis. Rabbits in all groups were then allocated to 5 subgroups. Then, they were subjected to intraabdominal pressures of 0, 6, 9, 12, and 15 mm Hg, respectively. Acute kidney injury was assessed by measuring serum creatinine (Scr), blood urea nitrogen (BUN), tubular cell apoptosis, kidney injury molecule-1 (KIM-1) and cysteine-rich 61 (Cyr-61/CCN1) expression., Results: Acute kidney injury with increased tubular apoptosis and KIM-1 and Cyr-61 expression occurred when intraabdominal pressure reached 15, 15 and 9 mm Hg in PN, PM and PS groups, respectively. The Scr and BUN levels were similar in all groups., Conclusions: In rabbits, kidneys with severe hydronephrosis were more likely to suffer acute injury when they were exposed to pneumoperitoneal pressure., (© 2014 S. Karger AG, Basel.)

Purpose: Surgical navigation based on preoperative images partly overcomes some of the drawbacks of minimally invasive interventions - reduction of free sight, lack of dexterity and tactile feedback. The usefulness of preoperative images is limited in laparoscopic liver surgery, as the liver shifts due to respiration, induction of pneumoperitoneum and surgical manipulation. In this study, we evaluated the shift and deformation in an animal liver caused by respiration and pneumopertioneum using intraoperative cone beam CT., Material and Methods: 3D cone beam CT scans were acquired with arterial contrast. The centerlines of the segmented vessels were extracted from the images taken at different respiration and pressure settings. A non-rigid registration method was used to measure the shift and deformation. The mean Euclidean distance between the annotated landmarks was used for evaluation., Results: A shift and deformation of 44.6 mm on average was introduced due to the combined effect of respiration and pneumoperitoneum. On average 91% of the deformations caused by the respiration and pneumoperitoneum were recovered., Conclusion: The results can contribute to the use of intraoperative imaging to correct for anatomic shift so that preoperative data can be used with greater confidence and accuracy during guidance of laparoscopic liver procedures.

Laparoscopic surgery techniques have been increasingly preferred to classic laparotomy by surgeons since 1987. However, this method may have some side effects on different intraabdominal organs including kidneys. The aim of this study is to evaluate the effects of different pressures of CO2 on p53 related apoptosis in kidneys. Totally 24 male rats were divided into four equal groups. CO2 is insufflated into rats' intraabdominal cavity in two different pressures of 10 and 20 mmHg during 1 h. However, in sham group, only cannula was inserted, but no gas was insufflated. After 1 h, 30 min reperfusion was applied. At last, the kidneys were excised and p53 expression and apoptosis were evaluated immunohistochemically. All the data revealed that the number of apoptotic cell in kidney' tubular cells significantly increases in proportion to CO2 pressure level. On the other hand, p53 expression was detected only in the highest pressure. Because the low CO2 pressured group' rats had no p53 expression in kidneys, we suggest that this method can be safely used for abdominal surgery. At the same time, increasing in the number of apoptotic cells parallel to pressure also suggest that CO2 pressure level and application time are very important parameters during CO2 pneumoperitoneum.

Background: A standardized large animal model for controlled ICP manipulation within a relevant range and repetitive ICP measurements is missing. We sought to develop such a model on the base of controlled IPP changes induced by capnoperitoneum., Methods: We utilized six female pigs (mean body weight 59.5 ± 18.4 kg) for experiments. A ventricular catheter connected with a burr hole reservoir was implanted. ICP was measured directly as cm H2O within a riser tube after percutaneous cannulation of the reservoir. A noninvasive intraperitoneal pressure (IPP) measurement was established (intravesical). Animals were placed in lateral position and a capnoperitoneum was induced. Measurements of ICP, IPP, MAP and respiratory parameters were performed at baseline IPP and after CO2 insufflation to IPP levels of 20 and 30 mmHg., Results: Baseline IPP in lateral position referenced to median line was 9.8 (±2) mm Hg, while corresponding ICP was 10 (±2.2) mm Hg. After IPP elevation to 20 mmHg, ICP increased to 18.8 (±1.9) mm Hg. At 30 mmHg IPP, ICP increased to 22.8 (±2.8) mm Hg. Except peak airway pressure, all other parameters were kept constantly. Mean ICP variation in the individual subject was 13.4 (±2.5) mm Hg, while a ICP range from minimum 9 to maximum 31 mmHg was documented., Conclusions: We report a large animal model that allows (1) repeated measurement of the ICP and (2) manipulation of the ICP within a large pressure range by controlled IPP changes due to capnoperitoneum.

Background: This study was designed to determine the impact of the degree of obesity on respiratory mechanics and simple hemodynamic parameters at laparoscopic bariatric surgery., Methods: The patients were divided into two groups, each of which included 24 patients (a morbidly obese group and a super obese group) undergoing laparoscopic bariatric surgery. Dynamic respiratory compliance, respiratory resistance, and peak inspiratory pressures were measured at four time points: 10 min after anesthesia induction (T1: induction), 10 min after pneumoperitoneum (T2: pneumoperitoneum), 10 min after terminating pneumoperitoneum (T3: end-pneumoperitoneum), and before extubation (T4: extubation). The systolic, diastolic, and mean arterial pressures and the heart rate values were measured noninvasively in T0 (10 min before operation)., Results: Obesity was found to cause a statistically significant increase in respiratory resistance and a peak inspiratory pressure and a decrease in dynamic respiratory compliance. In the morbidly obese group, the lowest dynamic respiratory compliance was 37 ± 12 mL/cm H(2)O, but it was 33 ± 13 mL/cm H(2)O in the super obese group. The systolic pressure, diastolic pressure, and mean arterial pressure were found to decrease significantly in both groups., Conclusions: Morbid obesity and super obesity have negative effects on hemodynamics and respiratory mechanics.

The results of ultrasound (US) and X-ray studies were retrospectively studied in the diagnosis of circumscribed peritonitis in case of microperforation from duodenal ulcers at different stages of emergency medical care. Analysis of the findings has demonstrated that on admission and in its first hours the most effective diagnostic method is plain radiography that enables free gas accumulation to be found under the diaphragm and US study is of low informative value. Repeat targeted US study using expert-class scanners, with the well stated task based on clinical laboratory findings, is a high-informative diagnostic technique for circumscribed peritonitis in case of duodenal perforations.

An 18-month-old male infant was placed on high-frequency oscillatory ventilation for profound hypoxemia and subsequently developed tension pneumoperitoneum. He underwent a bedside exploratory laparotomy for suspected perforated viscus. No intestinal perforation was identified, and a diagnosis of tension pneumoperitoneum secondary to pneumatosis cystoides intestinalis was made. To our knowledge, this is the only report of a pediatric patient developing tension pneumoperitoneum from high-frequency oscillatory ventilation. A review of the literature examines the differential diagnosis, physiology, and treatment of tension pneumoperitoneum., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Background: To investigate whether the compartment pressure of the rectus sheath (CPRS) reflects the intra-abdominal pressure (IAP) under various conditions of intra-abdominal hypertension (IAH) in a pig model., Design: Prospective experimental study with in vivo pressure measurements., Setting: Institute for Clinical and Experimental Surgery, University of Saarland., Animals: Seven domestic male pigs (body weight 34.8+/-2.5 kg)., Interventions: Stepwise increase and decrease of IAP by means of CO(2) pneumoperitoneum. Continuous direct measurement of the IAP and correspondent indirect IAP measurement techniques including analysis of intravesical pressure (IVP), femoral vein pressure (FVP), and CPRS., Results: Bland-Altman analysis comparing direct IAP measurement with correspondent CPRS showed good agreement for IAP between 12 mm Hg and 30 mm Hg (bias -0.5 mm Hg, lower and upper limits of agreement (LLA/ULA) -3.5/2.5 mm Hg). FVP (bias -0.3 mm Hg, LLA/ULA -2.3/1.6 mm Hg) and IVP (bias 0.4 mm Hg, LLA/ULA -2.1/2.9 mm Hg) demonstrated similar results compared with direct IAP measurement. Agreement was worse for all indirect IAP measurement techniques for IAP<12 mm Hg., Conclusions: CPRS accurately reflects IAP for IAP> or =12 mm Hg. Accuracy is similar to established indirect IAP measurement techniques., (Copyright 2010 Elsevier Inc. All rights reserved.)

Background: The metabolic changes associated with carbon dioxide (CO(2)) pneumoperitoneum include metabolic acidosis and lowered intra-abdominal pH values. An experimental study was performed to evaluate the effect of CO(2) pneumoperitoneum on esophageal and gastric smooth muscle sensitivity in response to several agonists., Methods: Wistar albino rats, weighing 200-250 g, were allocated into three groups. After anesthetization with ketamine hydrochloride and xylazine, abdominal esophagus, gastroesophageal junction, and gastric fundus were removed via median laparotomy in the control group. In the oxygen (O(2)) group, a 16G catheter was inserted into the abdomen above the umbilicus and insufflated with 95% O(2) and 5% CO(2) with a pressure of 10 mm Hg. In the CO(2) group, CO(2) was insufflated at the same pressure within the same time and the tissues were removed at the end of a 60 min period of pneumoperitoneum. Abdominal esophageal segment (n:6), gastroesophageal junction (n:6) and gastric fundus (n:12) were suspended under 0.5 to 2 g resting tension in Tyrode solution in organ baths. Contraction responses were obtained by carbachol and serotonin and relaxation responses were evaluated by isoproterenol in each group. All the responses were compared by nonparametric Kruskal Wallis test., Results: Carbachol and serotonin induced contractile responses of abdominal segments, gastroesophageal junction, and gastric fundus showed no difference between the control, O(2), and CO(2) groups (P > 0.05). Isoproterenol relaxation responses of the three groups were also not statistically different from each other (P > 0.05)., Conclusion: CO(2) pneumoperitoneum of 60 min has no influence on esophageal and gastric smooth muscle responses to different agonists in rats., (Copyright 2010 Elsevier Inc. All rights reserved.)

Objective: To determine the effect of CO(2) pneumoperitoneum on the ovaries in an experimental pneumoperitoneum model., Design: Experimental controlled study., Setting: University hospital., Patient(s): Sixteen adult female conventional rabbits., Intervention(s): Group I (8 rabbits) was not subjected to intra-abdominal pressure (IAP). In group II (8 rabbits), IAP insufflation was performed at 12 mm Hg. In total, 60 minutes of pneumoperitoneum and 10 minutes of reperfusion were maintained. Ovarian blood flow (OBF) was studied using laser Doppler flowmetry. The time points of OBF measurements were as follows: OBFbaseline, 10 minutes before insufflation; OBF30min, 30 minutes after pneumoperitoneum; OBF60min, 60 minutes after pneumoperitoneum; and OBFreperfusion, 10 minutes after pneumoperitoneum desufflation. Mean OBF changes during CO(2) pneumoperitoneum (OBFmean) were also assessed., Main Outcome Measure(s): Blood perfusion units, tissue malondialdehyde values, and histopathologic damage scores., Result(s): In group II, mean OBF values were significantly lower than in group I, especially for OBF30min, OBF60min, OBFreperfusion, and OBFmean. The mean tissue malondialdehyde value for group II was significantly higher than in the control group (104.48 +/- 20.07 nmol/g vs. 64.12 +/- 8.77 nmol/g, respectively). Compared with group I, in group II histologic specimens of the ovaries had higher scores for follicular cell degeneration, vascular congestion, hemorrhage, and inflammatory cell infiltration., Conclusion(s): Pneumoperitoneum, even at normal IAP levels, leads to significant oxidative stress-induced biochemical and histologic damage to the ovaries., (Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

A method to maintain organ blood flow during laparoscopic surgery has not been developed. Here we determined if ethyl nitrite, an S-nitrosylating agent that would maintain nitric oxide bioactivity (the major regulator of tissue perfusion), might be an effective intervention to preserve physiologic status during prolonged pneumoperitoneum. The study was conducted on appropriately anesthetized adult swine; the period of pneumoperitoneum was 240 minutes. Cohorts consisted of an anesthesia control group and groups insufflated with CO2 alone or CO2 containing fixed amounts of ethyl nitrite (1-300 ppm). Insufflation with CO2 alone produced declines in splanchnic organ blood flows and it reduced circulating levels of S-nitrosohemoglobin (i.e., nitric oxide bioactivity); these reductions were obviated by ethyl nitrite. In a specific example, preservation of kidney blood flow with ethyl nitrite kept serum creatinine and blood urea nitrogen concentrations constant whereas in the CO2 alone group both increased as kidney blood flow declined. The data indicate ethyl nitrite can effectively attenuate insufflation-induced decreases in organ blood flow and nitric oxide bioactivity leading to reductions in markers of acute tissue injury. This simple intervention provides a method for controlling a major source of laparoscopic-related morbidity and mortality: tissue ischemia and altered postoperative organ function.

Background: In the anesthetic management of laparoscopic surgery, hemodynamic changes appear on the skin incision and pneumoperitoneum. Remifentanil may suppress the cardiovascular changes on the pneumoperitoneum in the laparoscopic cholecystectomy (LC)., Method: One hundred-seven patients scheduled for LC were assigned into two groups; remifentanil (R), and epidural (E) groups. In R group, remifentanil was administered at 0.2 microg x kg(-1) x min(-1) from the induction of anesthesia. In E group, an epidural catheter was placed between T10-12 and 0.2% ropivacaine was infused continuously at 6 ml x hr(-1) via epidural catheter. Anesthesia was maintained by propofol at 5 mg x kg(-1) x hr(-1) following the induction by propofol and vecuronium in both groups. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and bispectral index (BIS) were compared at the entrance of the operating room, skin incision, pneumoperitoneum and extubation of the endotracheal tube between two groups., Results: At the pneumoperitoneum, statistical significance was found in HR, but there was no significant difference in blood pressure and BIS between the two groups., Conclusions: Compared with epidural anesthetic management, remifentanil suppresses significantly the elevation of heart rate, but not blood pressure at the pneumoperitoneum.

Abdominal compartment syndrome (ACS) is defined as an increased intra-abdominal pressure with adverse physiologic consequences. Abdominal compartment syndrome caused by perforated peptic ulcer is rare owing to early diagnosis and management. Delayed recognition of perforated peptic ulcer with pneumoperitoneum, bowel distension, and decreased abdominal wall compliance can make up a vicious circle and lead to ACS. We report a case of perforated peptic ulcer associated with ACS. A 74-year-old man with old stroke and dementia history was found to have distended abdomen, edema of bilateral legs, and cyanosis. Laboratory tests revealed deterioration of liver and kidney function. Abdominal compartment syndrome was suspected, and image study was arranged to find the cause. The study showed pneumoperitoneum, contrast stasis in heart with decreased caliber of vessels below the abdominal aortic level, and diffuse lymphedema at the abdominal walls. Emergent laparotomy was performed. Perforated peptic ulcer was noted and the gastrorrhaphy was done. The symptoms, and liver and kidney function improved right after emergent operation.

Pneumoperitoneum (PP), or air within the abdominal cavity, is frequently the harbinger of serious abdominal pathology and frequently represents visceral perforation. Most cases of PP ultimately need surgical exploration and intervention. In addition, cases of nonsurgical PP have also been described in the literature, and it has been suggested that these cases can be managed conservatively. This report documents the occurrence of incidentally found PP. However, it is unclear how often PP is found incidentally, and more importantly how to manage the patient with clinically unsuspected PP without peritoneal signs. Future research could help to better determine the incidence of unsuspected PP and to validate the various diagnostic and treatment algorithms in the literature.

Background: Although aggressive fluid hydration prevents a decrease in renal cortical perfusion (RCP) during laparoscopic donor nephrectomy, excess fluid is deleterious. We assessed whether goal-directed fluid administration, based on hemodynamic measures, would maintain RCP during pneumoperitoneum with less fluid loading., Methods: In a pilot study of 7 pigs, goal-directed fluid administration was guided by monitoring of stroke volume (SV) by esophageal Doppler measurement. During 15 mmHg CO(2) pneumoperitoneum, a bolus of 5 mL/kg 0.9% NaCl was given when SV decreased to 90% of baseline. Next, 18 pigs were randomized into 3 groups: low fluid (5 mL/kg per hour), high fluid (25 mL/kg per hour) and goal directed. Urine output, heart rate, mean arterial pressure, cardiac output, SV, and RCP were recorded every 15 minutes., Results: Pilot data revealed mean RCP (mL/min per 100 g) was maintained (40 vs 39) during pneumoperitoneum using goal-directed therapy. In the randomized study, RCP was decreased in the low fluid group (43 vs 29; P= .02), but maintained in the high (46 vs 40) and goal-directed (42 vs 39) groups. Mean fluid administered in the goal-directed group during pneumoperitoneum was 10 mL/kg and only 3 of 6 of pigs required boluses. Urine output was decreased in all 3 groups., Conclusion: A goal-directed strategy during pneumoperitoneum allows for tailored fluid administration and maintains RCP with lower volumes of intravenous fluid.

Background: We have shown previously that abdominal insufflation with CO(2) increases serum levels of IL-10 and TNFalpha and increases survival among animals with lipopolysaccharide (LPS)-induced sepsis, even after a laparotomy. We demonstrated previously that the effect of CO(2) is not from changes in systemic pH, although the peritoneum is locally acidotic during abdominal insufflation with CO(2) even when systemic pH is corrected. We hypothesized that acidification of the peritoneum via means other than CO(2) insufflation would produce alterations in the inflammatory response similar to those associated with CO(2) pneumoperitoneum., Methods: In total, 42 rats were randomized into 7 groups (n = 6): 1) LPS only, 2) anesthesia control, 3) helium pneumoperitoneum, 4) CO(2) pneumoperitoneum, 5) buffered mild acid lavage, 6) buffered strong acid lavage, and 7) buffered strong acid lavage + helium pneumoperitoneum. Animals received anesthesia with vaporized isoflurane (except the LPS-only group) and their respective abdominal treatment (pneumoperitoneum and/or lavage) for 30 min followed immediately by stimulation with systemic LPS (1 mg/kg, IV). Blood was harvested via cardiac puncture 60 min after LPS injection, and serum levels of IL-10 and TNFalpha levels were determined by enzyme-linked immunosorbent assay., Results: Mean peritoneal pH decreased (P < .05) after CO(2) pneumoperitoneum, buffered strong acid lavage, and buffered strong acid lavage + helium pneumoperitoneum, and it decreased (P = .1) after helium pneumoperitoneum alone and buffered mild acid lavage. IL-10 levels were increased (P < .01), and TNFalpha levels decreased (P < .001) among animals with acidic peritoneal cavities compared with animals with pH-normal peritoneal cavities. Decreasing peritoneal pH correlated with both increasing IL-10 levels (r = -.465, P < .01) and decreasing TNFalpha levels (r = 0.448, P < .01). Among animals with peritoneal acidosis, there were no differences in levels of IL-10 or TNFalpha regardless of insufflation status (P > .05 for both cytokines)., Conclusions: Acidification of the peritoneal cavity whether by abdominal insufflation or by peritoneal acid lavage increases serum IL-10 and decreases serum TNFalpha levels in response to systemic LPS challenge. The degree of peritoneal acidification correlates with the degree of inflammatory response reduction. These results support the hypothesis that pneumoperitoneum-mediated attenuation of the inflammatory response after laparoscopic surgery occurs via a mechanism of peritoneal cell acidification.

Pneumoperitoneum is considered to be a surgical emergency as it nearly always indicates a perforated abdominal viscus. However, in rare cases, the presence of 'free gas under diaphragm' may not imply the need for emergent laparotomy, as pneumoperitoneum can occur without any gastrointestinal leakage. Here we report a rare case of a previously healthy boy with pneumoperitoneum associated with pneumonia and perform a review of the literature to explore the etiological mechanisms and the pathophysiology of non-surgical pneumoperitoneum.

Pneumoperitoneum usually indicates a surgical emergency because of visceral perforation in 85 to 95% of cases. Spontaneous pneumoperitoneum without peritonitis is a rare phenomenon which poses a dilemma for the surgeon who is faced with this problem. Some cases of pneumoperitoneum can and should be managed conservatively. We report three cases of pneumoperitoneum and describe their outcomes. Two cases were treated conservatively, and one underwent laparotomy but no perforated viscus was found. We review the aetiological mechanisms and the pathophysiology of the appearance of intra-abdominal free gas. Furthermore, a compilation of other aetiologies of pneumoperitoneum without peritonitis as reported in the literature is presented. Pneumoperitoneum, preceded by a reasonable clinical history in a patient with an adequate abdominal examination, may warrant continued observation, thus avoiding an unnecessary laparotomy.

Purpose: to study the effect of Propranolol on hemodynamic response due to airway manipulation and carbon dioxide pneumoperitoneum on laparoscopic cholecystectomy cases., Methods: 63 patients undergoing laparoscopic cholecystectomy under general anaesthesia were randomly divided into 3 groups; group 1 received 1.0 mg of Propranolol, group 2 received 0.5 mg of Propranolol and group 3 received 1 ml saline 5 minutes before induction of anaesthesia. Haemodynamic parameters were recorded for every 5 minutes from basal to 5 minutes after extubation and analyzed., Results: Balanced anaesthesia used in our set up is effective in decreasing stress response due to airway manipulation (laryngoscopy and endotracheal intubation) but not effective in that due to CO2 pneumoperitoneum. Propranolol 1 mg 5 minutes before anaesthesia is effective in decreasing stress response due to airway manipulation and CO2 pneumoperitoneum in these groups of patients., Conclusion: Propranolol effectively blunts the stress response due to CO2 pneumoperitoneum during laparoscopic cholecystectomy.