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Background: Longitudinal incision is the commonly used incision for entry into the submucosal space during peroral endoscopic myotomy (POEM) for esophageal motility disorders. Transverse incision is another alternative for entry and retrospective data suggest it has less operative time and chance of gas-related events. Methods: This was a single-center, randomized trial conducted at a tertiary care hospital. Patients undergoing POEM for esophageal motility disorders were randomized into group A (longitudinal incision) and group B (transverse incision). The primary objective was to compare the time needed for entry into the submucosal space. The secondary objectives were to compare the time needed to close the incision, number of clips required to close the incision, and development of gas-related events. The sample size was calculated as for a non-inferiority design using Kelsey method. Results: Sixty patients were randomized (30 in each group). On comparing the 2 types of incisions, there was no difference in entry time [3 (2, 5) vs 2 (1.75, 5) min, p = 0.399], closure time [7 (4, 13.5) vs 9 (6.75, 19) min, p = 0.155], and number of clips needed for closure [4 (4, 6) vs 5 (4, 7), p = 0.156]. Additionally, the gas-related events were comparable between the 2 groups (capnoperitoneum needing aspiration—5 vs 2, p = 0.228, and development of subcutaneous emphysema—3 vs 1, p = 0.301). Conclusion: This randomized trial shows comparable entry time, closure time, number of clips needed to close the incision, and gas-related events between longitudinal and transverse incisions. Registration number: CTRI/2021/08/035829. [ABSTRACT FROM AUTHOR]

Laparoscopic access, a critical yet challenging step in surgical procedures, often leads to complications. Existing systems, such as improved Veress needles and optical trocars, offer limited safety benefits but come with elevated costs. In this study, a prototype of a novel technology for guiding needle interventions based on vibroacoustic signals is evaluated in porcine cadavers. The prototype consistently detected successful abdominal cavity entry in 100% of cases during 193 insertions across eight porcine cadavers. The high signal quality allowed for the precise identification of all Veress needle insertion phases, including peritoneum puncture. The findings suggest that this vibroacoustic-based guidance technology could enhance surgeons' situational awareness and provide valuable support during laparoscopic access. Unlike existing solutions, this technology does not require sensing elements in the instrument's tip and remains compatible with medical instruments from various manufacturers. [ABSTRACT FROM AUTHOR]

Laparoscopic access, a critical yet challenging step in surgical procedures, often leads to complications. Existing systems, such as improved Veress needles and optical trocars, offer limited safety benefits but come with elevated costs. In this study, a prototype of a novel technology for guiding needle interventions based on vibroacoustic signals is evaluated in porcine cadavers. The prototype consistently detected successful abdominal cavity entry in 100% of cases during 193 insertions across eight porcine cadavers. The high signal quality allowed for the precise identification of all Veress needle insertion phases, including peritoneum puncture. The findings suggest that this vibroacoustic-based guidance technology could enhance surgeons’ situational awareness and provide valuable support during laparoscopic access. Unlike existing solutions, this technology does not require sensing elements in the instrument’s tip and remains compatible with medical instruments from various manufacturers.

Background: Per-oral endoscopic myotomy (POEM) has become an accepted minimally invasive alternative to Heller myotomy for the treatment of achalasia and other disorders of esophageal dysmotility. One associated adverse event is the inadvertent creation of capnoperitoneum. A proposed mechanism is that extension of the submucosal tunnel below the esophageal hiatus and onto the gastric wall leads to transmural perforation. We hypothesized that the use of impedance planimetry with the endoscopic functional luminal imaging probe (EndoFLIP) more accurately identifies the esophagogastric junction and helps to better define the myotomy's ideal limits, thus lowering the incidence of inadvertent capnoperitoneum. Methods: This is a single-center, retrospective review of consecutive POEM cases from 06/11/2011 to 08/08/2022, with EndoFLIP introduced in 2017. Patient and procedural characteristics, including the incidence of clinically significant capnoperitoneum and decompression, were analyzed using univariate and multivariable linear regression statistics. Results: There were 140 POEM cases identified, 74 (52.9%) of which used EndoFLIP. Clinically significant capnoperitoneum was encountered in 26 (18.6%) cases, with no differences in patient characteristics between those who had capnoperitoneum and those who did not. There was a decreased incidence of capnoperitoneum in cases using EndoFLIP compared to those without (n = 6, 23% vs n = 20, 77%, p = 0.001), with zero instances in the final 56 cases. After adjusting for potentially confounding factors, EndoFLIP use was associated with a − 15.93% (95% confidence interval − 30.68%, − 1.18%) decrease in procedure duration. Conclusions: The routine use of EndoFLIP during POEM was associated with decreased incidence of clinically significant capnoperitoneum, potentially due to improved myotomy tailoring and decreased duration of insufflation with shorter procedure times. [ABSTRACT FROM AUTHOR]

Laparoscopic surgery with capnoperitoneum brings many advantages to patients, but also emphasizes the negative impact of anesthesia and mechanical ventilation on the lungs. Even though many studies use electrical impedance tomography (EIT) for lung monitoring during these surgeries, it is not clear what the best position of the electrode belt on the patient's thorax is, considering the cranial shift of the diaphragm. We monitored 16 patients undergoing a laparoscopic surgery with capnoperitoneum using EIT with two independent electrode belts at different tomographic levels: in the standard position of the 4th–6th intercostal space, as recommended by the manufacturer, and in a more cranial position at the level of the axilla. Functional residual capacity (FRC) was measured, and a recruitment maneuver was performed at the end of the procedure by raising the positive end-expiratory pressure (PEEP) by 5 cmH2O. The results based on the spectral analysis of the EIT signal show that the ventilation-related impedance changes are not detectable by the belt in the standard position. In general, the cranial belt position might be more suitable for the lung monitoring during the capnoperitoneum since the ventilation signal remains dominant in the obtained impedance waveform. FRC was significantly decreased by the capnoperitoneum and remained lower also after desufflation. [ABSTRACT FROM AUTHOR]

Hyun Jung Lee,1 Ji Seon Chae,2 Sang-Mee An,2 Hye-Won Oh,1 Youn Jin Kim,1 Jae Hee Woo1 1Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, Seoul, South Korea; 2Department of Anesthesiology and Pain Medicine, Ewha Womans University Seoul Hospital, Seoul, South KoreaCorrespondence: Jae Hee Woo, Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, 260 Gonghangdaero, Gangseo-gu, Seoul, 07804, South Korea, Tel +82-2-6986-4300, Fax +82-2-6986-4960, Email jheewoo@ewha.ac.krPurpose: Monitoring end-tidal carbon dioxide partial pressure (PETCO2) is a noninvasive, continuous method, but its accuracy is reduced by prolonged capnoperitoneum and the steep Trendelenburg position in robot-assisted radical prostatectomy (RARP). Transcutaneous carbon dioxide partial pressure (PTCCO2) monitoring, which is not affected by ventilator–perfusion mismatch, has been suggested as a suitable alternative. We compared the agreement of noninvasive measurements with the arterial carbon dioxide partial pressure (PaCO2) over a long period of capnoperitoneum, and investigated its sensitivity and predictive power for detecting hypercapnia.Patients and Methods: The patients who underwent RARP were enrolled in this study prospectively. Intraoperative measurements of PETCO2, PTCCO2, and PaCO2 were analyzed. The primary outcome was the agreement of noninvasive monitoring with PaCO2 during prolonged capnoperitoneum. Bias and precision between noninvasive measurements and PaCO2 were assessed using Bland–Altman analysis. The bias and mean absolute difference were compared using a two-tailed Wilcoxon signed-rank test for pairs. The secondary outcome was the sensitivity and predictive power for detecting hypercapnia. To assess this, the Yates corrected chi-square test and the area under the receiver operating characteristic curve were used.Results: The study analyzed 219 datasets from 46 patients. Compared with PETCO2, PTCCO2 had lower bias, greater precision, and better agreement with PaCO2 throughout the RARP. The mean absolute difference in PETCO2 and PaCO2 was larger than that of PTCCO2 and PaCO2, and continued to exceed the clinically acceptable range of 5 mmHg after 1 hour of capnoperitoneum. The sensitivity during capnoperitoneum and overall predictive power of PTCCO2 for detecting hypercapnia were significantly higher than those of PETCO2, suggesting a greater contribution to ventilator adjustment, to treat hypercapnia.Conclusion: PTCCO2 monitoring measured PaCO2 more accurately than PETCO2 monitoring during RARP requiring prolonged capnoperitoneum and a steep Trendelenburg position. PTCCO2 monitoring also provides more sensitive measurements for ventilator adjustment and detects hypercapnia more effectively than PETCO2 monitoring.Keywords: intraoperative carbon dioxide monitoring, capnoperitoneum, robotic surgery, end-tidal carbon dioxide monitoring, general anesthesia

Laparoscopic surgery with capnoperitoneum brings many advantages to patients, but also emphasizes the negative impact of anesthesia and mechanical ventilation on the lungs. Even though many studies use electrical impedance tomography (EIT) for lung monitoring during these surgeries, it is not clear what the best position of the electrode belt on the patient’s thorax is, considering the cranial shift of the diaphragm. We monitored 16 patients undergoing a laparoscopic surgery with capnoperitoneum using EIT with two independent electrode belts at different tomographic levels: in the standard position of the 4th–6th intercostal space, as recommended by the manufacturer, and in a more cranial position at the level of the axilla. Functional residual capacity (FRC) was measured, and a recruitment maneuver was performed at the end of the procedure by raising the positive end-expiratory pressure (PEEP) by 5 cmH2O. The results based on the spectral analysis of the EIT signal show that the ventilation-related impedance changes are not detectable by the belt in the standard position. In general, the cranial belt position might be more suitable for the lung monitoring during the capnoperitoneum since the ventilation signal remains dominant in the obtained impedance waveform. FRC was significantly decreased by the capnoperitoneum and remained lower also after desufflation.

Creating surgical access is a critical step in laparoscopic surgery. Surgeons have to insert a sharp instrument such as the Veress needle or a trocar into the patient's abdomen until the peritoneal cavity is reached. They solely rely on their experience and distorted tactile feedback in that process, leading to a complication rate as high as 14% of all cases. Recent studies have shown the feasibility of surgical support systems that provide intraoperative feedback regarding the insertion process to improve laparoscopic access outcomes. However, to date, the surgeons' requirements for such support systems remain unclear. This research article presents the results of an explorative study that aimed to acquire data about the information that helps surgeons improve laparoscopic access outcomes. The results indicate that feedback regarding the reaching of the peritoneal cavity is of significant importance and should be presented visually or acoustically. Finally, a solution should be straightforward and intuitive to use, should support or even improve the clinical workflow, but also cheap enough to facilitate its usage rate. While this study was tailored to laparoscopic access, its results also apply to other minimally invasive procedures. [ABSTRACT FROM AUTHOR]

Peroral endoscopic myotomy (POEM) is natural orifice transluminal endoscopic surgery to treat esophageal achalasia. During POEM, cardiovascular dynamics can be impaired by capnoperitoneum, capnomediastinum, and systemic carbon dioxide accumulation. We systematically investigated changes in cardiovascular dynamics during POEM. We included 31 patients having POEM in this single-center prospective observational study. Before and every 5 min during POEM we measured mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), stroke volume index (SVI), and systemic vascular resistance index (SVRI) using non-invasive finger cuff-derived pulse wave analysis. During POEM, the median MAP was higher than the median baseline MAP of 77 (67;86) mmHg. HR (median at baseline: 67 (60;72) bpm), CI (2.8 (2.5;3.2) L/min/m2), SVI (42 (34;51) mL/m2), and SVRI (1994 (1652; 2559) dyn × s × cm−5 × m−2) remained stable during POEM. Mixed model-derived 95% confidence limits of hemodynamic variables during POEM were 72 to 106 mmHg for MAP, 65 to 79 bpm for HR, 2.7 to 3.3 L/min/m2 for CI, 37 and 46 mL/m2 for SVI, and 1856 and 2954 dyn × s × cm−5 × m−2 for SVRI. POEM is a safe procedure with regard to cardiovascular dynamics as it does not markedly impair MAP, HR, CI, SVI, or SVRI. [ABSTRACT FROM AUTHOR]

Background and Aims: During laparoscopic surgery, a capnoperitoneum is created to optimize the operating space for surgeons. One effect of this is abdominal pressure which alters the physiological thoraco-abdominal configuration and pushes the diaphragm and lungs cranially. Since the lung image acquired by electrical impedance tomography (EIT) depends on the conditions within the thorax and abdomen, it is crucial to know the diaphragm position to determine the effect of diaphragm shift on EIT thorax image. Methods: The presence of diaphragm in the region of EIT measurement was determined by ultrasound in 20 patients undergoing laparoscopic surgery. Data were obtained in the supine position during spontaneous breathing in a mechanically ventilated patient under general anesthesia with muscle relaxation and in a mechanically ventilated patient under general anesthesia with muscle relaxation during capnoperitoneum. Results: The diaphragm was shifted cranially during capnoperitoneum. The diaphragm detection rate rose by 10% during capnoperitoneum at the fifth intercostal space, from 55% to 65% and by 10% from 0% at mid-sternal level compared to mechanical ventilation without capnoperitoneum. Conclusion: The diaphragm was detected in the area contributing to the creation of the thoracic EIT image. Considering the cranial shift of diaphragm caused by excessive intra-abdominal pressure, the impedance changes in the abdomen and the principle of EIT, we assume there could be a significant impact on EIT image of the thorax acquired during capnoperitoneum. For this reason, for lung monitoring using EIT during capnoperitoneum, the manufacturer's recommendation for electrode belt position is not appropriate. The study was registered in ClinicalTrials.gov with an identifier NCT03038061.

Objective: To review the effects of carbon dioxide pneumoperitoneum during laparoscopy, evaluate alternative techniques to establishing a working space and compare this to current recommendations in veterinary surgery. Study Design: Literature review. Sample Population: 92 peer-reviewed articles. Methods: An electronic database search identified human and veterinary literature on the effects of pneumoperitoneum (carbon dioxide insufflation for laparoscopy) and alternatives with a focus on adaptation to the veterinary field. Results: Laparoscopy is the preferred surgical approach for many human and several veterinary procedures due to the lower morbidity associated with minimally invasive surgery, compared to laparotomy. The establishment of a pneumoperitoneum with a gas most commonly facilitates a working space. Carbon dioxide is the preferred gas for insuffation as it is inert, inexpensive, noncombustible, colorless, excreted by the lungs and highly soluble in water. Detrimental side effects such as acidosis, hypercapnia, reduction in cardiac output, decreased pulmonary compliance, hypothermia and post-operative pain have been associated with a pneumoperitoneum established with CO2 insufflation. As such alternatives have been suggested such as helium, nitrous oxide, warmed and humidified carbon dioxide and gasless laparoscopy. None of these alternatives have found a consistent benefit over standard carbon dioxide insufflation. Conclusions: The physiologic alterations seen with CO2 insufflation at the current recommended intra-abdominal pressures are mild and of transient duration. Clinical Significance: The current recommendations in veterinary laparoscopy for a pneumoperitoneum using carbon dioxide appear to be safe and effective. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to evaluate the effects of pneumoperitoneum on liver function during and after laparoscopic cholecystectomy.Methods: This prospective study comprised a total of 165 patients, who were divided into two groups: The first group had low-pressure pneumoperitoneum (12 mm Hg; N = 78) and the second group had high-pressure pneumoperitoneum (14 mm Hg; N = 87). A detailed statistical analysis included sex, age, operation time, and liver function tests including total bilirubin, gamma-glutamyl transferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, fibrinogen, and lactate dehydrogenase (LDH), which were obtained preoperatively and 24 h, 7 days, and 30 days postoperatively. The statistical hypotheses were tested with a t test, Mann-Whitney test, chi-square test, Friedman test, and Wilcoxon's test.Results: There was no statistical difference between the two groups considering age, gender, and operation time (p = 0.740, p = 0.255, and p = 0.480, respectively). There was also no statistical difference in the median values of bilirubin, AST, GGT, LDH, albumin, and fibrinogen between the two groups. There was a significant statistical difference between the two groups in the median values of ALT on the 30th postoperative day (p = 0.045). There was a statistical difference for all hematochemical parameters as a function of time, independent of the level of intra-abdominal pressure (IAP).Conclusion: There were no statistically significant differences in the values of parameters of structural damage to the liver between the two groups, but within the groups themselves. From this we conclude that both values of elevated IAP cause microstructural and functional damage to the liver. [ABSTRACT FROM AUTHOR]

Laparoscopy is a growing field in veterinary medicine, although guidelines are lacking. The objective of this study was to evaluate the pressure–volume curve during capnoperitoneum in cats. A total of 59 female cats were scheduled for routine laparoscopy. Pressure and volume data were recorded and processed, and the yield point of the curve was calculated using a method based on a capacitor discharging function. For the remaining 40 cats, a linear-like pressure–volume curve was observed until a yield point with a mean cutoff pressure (COP) of 6.44 ± 1.7 mmHg (SD) (range, 2.72–13.00 mmHg) and a mean cutoff volume (COV) of 387 ± 144.35 mL (SD) (range, 178.84–968.43 mL) was reached. The mean mL/kg CO2 value in cats was 208 ± 34.69 mL/kg (range, 100.00–288.46 mL/kg). The COV correlated with COP and body weight but not with body condition score (BCS). COP correlated only with the COV. This study suggests that feline patients have a pressure–volume curve similar to that of canine patients, and the same pressure limit recommendations can be used for both species. After a yield point of 6.44 mmHg is reached, the increment in volume decreases exponentially as the intra-abdominal pressure (IAP) increases.

Objective: To review the effects of carbon dioxide pneumoperitoneum during laparoscopy, evaluate alternative techniques to establishing a working space and compare this to current recommendations in veterinary surgery. Study Design: Literature review. Sample Population: 92 peer-reviewed articles. Methods: An electronic database search identified human and veterinary literature on the effects of pneumoperitoneum (carbon dioxide insufflation for laparoscopy) and alternatives with a focus on adaptation to the veterinary field. Results: Laparoscopy is the preferred surgical approach for many human and several veterinary procedures due to the lower morbidity associated with minimally invasive surgery, compared to laparotomy. The establishment of a pneumoperitoneum with a gas most commonly facilitates a working space. Carbon dioxide is the preferred gas for insufflation as it is inert, inexpensive, noncombustible, colorless, excreted by the lungs and highly soluble in water. Detrimental side effects such as acidosis, hypercapnia, reduction in cardiac output, decreased pulmonary compliance, hypothermia and post-operative pain have been associated with a pneumoperitoneum established with CO2 insufflation. As such alternatives have been suggested such as helium, nitrous oxide, warmed and humidified carbon dioxide and gasless laparoscopy. None of these alternatives have found a consistent benefit over standard carbon dioxide insufflation. Conclusions: The physiologic alterations seen with CO2 insufflation at the current recommended intra-abdominal pressures are mild and of transient duration. Clinical Significance: The current recommendations in veterinary laparoscopy for a pneumoperitoneum using carbon dioxide appear to be safe and effective.

Respiratory and cardiovascular changes in normocapnic dogs undergoing laparoscopic ovariectomy are described in this report. To-date, changes during a standardised ventilation pattern, irrespective of end-tidal CO2 (EtCO2) levels, have not been reported. This study was undertaken to describe these changes. Forty bitches undergoing laparoscopic ovariectomy were enrolled in a prospective double-blind randomised clinical trial. They were first anaesthetised with medetomidine-butorphanol-propofol and then maintained with isoflurane in oxygen-air. Ventilation pattern was pressure-controlled, volume-limited. After stabilisation, atracurium 0.4 mg/kg (ATR group, n = 20) or saline 0.04 ml/kg (SAL group, n = 20) was administered intravenously. Capnoperitoneum was then established with an intra-abdominal pressure setting of 10 mmHg. Collected data included heart rate (HR), non-invasive blood pressure, EtCO2, oxygen saturation of haemoglobin, and tidal volume and neuromuscular blockade (train-of-four). Data were recorded before administration of atracurium or saline, and at 2, 5, and 10 min thereafter. Subsequently, insufflation of CO2 was commenced. After capnoperitoneum was established, data were recorded at 2, 5 and 10 min. Time of capnoperitoneum induction and duration, time of ovary searching and excision and total time of capnoperitoneum and surgery were also recorded. For statistical analysis, the Shapiro Wilk test, ANOVA with repeated measures and Student's t-test for independent samples were used (P < 0.05). Significant increases in EtCO2 were observed in patients 5 min after atracurium administration and 5 min after capnoperitoneum was established in the ATR group, when compared to the SAL group. No other differences were found. Administration of atracurium in dogs undergoing laparoscopic ovariectomy with a standardised ventilation pattern did not result in clinically important differences in selected cardiovascular and respiratory variables and surgical times in comparison with non-relaxed dogs. Thus, the use of atracurium in laparoscopic ovariectomy does not result in any benefit for patients or surgeons.

Background: Minimally invasive surgery (MIS) has gained increasing importance in neonatal surgery but the effects on neonatal physiology remain unclear. We aimed to characterize the impact of capnoperitoneum on physiologic parameters in a small animal model for neonatal MIS.Material and Methods: Twenty-four 10-day-old Sprague Dawley rats underwent inhalative anesthesia (1% isoflurane in 100% O2 250 mL/minutes) and were allowed to breathe spontaneously. CO2 was insufflated into the abdominal cavity for 1 hour via a 24G cannula. Anesthetized litter mates without insufflation served as sham controls, those without any treatment as external controls. Continuous monitoring included O2-saturation, heart and respiration rate, pulse and breath distension. After euthanasia, blood gas analysis was performed.Results: All animals survived the experiment. Capnoperitoneum was best tolerated at a pressure of 2 mmHg and a flow of 0.5 L/minutes. A significant decrease in heart rate was observed within the first 30 minutes of insufflation comparing the CO2 and sham group (P < .05). In both, the CO2 and sham group, postmortem pH-levels were lower and pCO2 levels were higher compared to external controls (P < .05). Additionally, levels of pCO2 were higher but pH levels remained unchanged in the CO2 compared to sham group (P < .05).Conclusion: We established a small animal model for neonatal laparoscopy. A pressure of 2 mmHg and flow of 0.5 L/minutes induced physiologic alterations but was well tolerated by the animals. These settings can be used in future studies on the impact of the capnoperitoneum in neonatal MIS. [ABSTRACT FROM AUTHOR]

Background and Aims. During laparoscopic surgery, a capnoperitoneum is created to optimize the operating space for surgeons. One effect of this is abdominal pressure which alters the physiological thoraco-abdominal configuration and pushes the diaphragm and lungs cranially. Since the lung image acquired by electrical impedance tomography (EIT) depends on the conditions within the thorax and abdomen, it is crucial to know the diaphragm position to determine the effect of diaphragm shift on EIT thorax image. Methods. The presence of diaphragm in the region of EIT measurement was determined by ultrasound in 20 patients undergoing laparoscopic surgery. Data were obtained in the supine position during spontaneous breathing in a mechanically ventilated patient under general anesthesia with muscle relaxation and in a mechanically ventilated patient under general anesthesia with muscle relaxation during capnoperitoneum. Results. The diaphragm was shifted cranially during capnoperitoneum. The diaphragm detection rate rose by 10% during capnoperitoneum at the fifth intercostal space, from 55% to 65% and by 10% from 0% at mid-sternal level compared to mechanical ventilation without capnoperitoneum. Conclusion. The diaphragm was detected in the area contributing to the creation of the thoracic EIT image. Considering the cranial shift of diaphragm caused by excessive intra-abdominal pressure, the impedance changes in the abdomen and the principle of EIT, we assume there could be a significant impact on EIT image of the thorax acquired during capnoperitoneum. For this reason, for lung monitoring using EIT during capnoperitoneum, the manufacturer's recommendation for electrode belt position is not appropriate. The study was registered in ClinicalTrials.gov with an identifier NCT03038061. [ABSTRACT FROM AUTHOR]

Background: Our previous work in a laparoscopic setting in piglets revealed that the systolic femoral artery pressure was approximately 5 % higher than its carotid counterpart, whereas the mean and diastolic values showed no significant difference. This remained idem when the intraabdominal pressure (IAP) was gradually increased. In this study, we aimed to investigate the effect of (1) intermittent IAP elevations and (2) a low cardiac output (CO) on the blood pressure (BP) difference cranially (carotid artery) and caudally (femoral artery) of a capnoperitoneum (ΔP = P a fem-P a carot).Methods: A total of twenty-two piglets (mean body weight 11.0 kg; range 8.9-13.3 kg) were studied. Of these, 14 underwent intermittent IAP elevations at 8 and 16 mmHg, and ΔP was measured. In another 8 piglets, a model of reduced CO was created by introducing an air embolism (2 ml/kg over 30 s) in the inferior caval vein (VCI) at 12 mmHg IAP to further assess the influence of this variable on ΔP.Results: Systolic ΔP remained at a mean of 5.6 mmHg and was not significantly affected by insufflation or exsufflation up to an IAP of 16 mmHg. Diastolic and mean values showed no differences between P a carot and P a fem. P a fem, systol remained higher than its carotid counterpart as long as the cardiac index (CI) was above 1.5 l/min/m2, but fell significantly below P a carot, systol at a low CI. There was no CO-dependent effect on diastolic and mean ΔP. Repeated IAP elevations do not significantly influence ΔP.Conclusions: Intermittent IAP elevations do not significantly influence ΔP. Despite of a CO-dependent inversion of systolic ΔP, mean BP measurements at the leg during laparoscopy remain representative even at low CO values. [ABSTRACT FROM AUTHOR]

Laparoscopy is not widely used as a tool to perform assisted reproduction techniques in South American cervids; thus, scarce information in literature is available regarding its effects and appropriate anesthetic protocols to perform it. This study evaluated the effect of laparoscopy on heart rate (HR), respiration rate (RR), saturation of oxyhemoglobin (SpO2) and rectal temperature (RT) of six female brown brocket deer (Mazama gouazoubira) anesthetized with ketamine (5mg/kg), xylazine (0.3mg/kg), midazolam (0.5mg/kg) combination i.v. and isoflurane. Twelve laparoscopies were performed and each animal was used twice with a 40-day interval. After anesthetized, the animals were placed in dorsal recumbency to perform laparoscopy procedure using abdominal CO2 insufflations (14.2 ± 2.39mmHg; M ± SE). The main events of the laparoscopy procedure were divided into three periods: animal without (P1) and with abdominal insufflation (P2) and abdominal insufflation with the hips raised at 45º (P3). As a control, the animals were anesthetized again 40 days after the last laparoscopy, and were maintained in a dorsal recumbency for the same average duration of the previous anesthesia and no laparoscopy procedure was conducted. The period of anesthesia for the controls was also divided into P1, P2, and P3 considering the average duration of these periods in previous laparoscopies performed. Data were analyzed through the (ANOVA) variance analysis followed by Tukey test and values at PA laparoscopia ainda é pouco utilizada como ferramenta para técnicas de reprodução assistida em cervídeos sul-americanos, não havendo informações sobre seus efeitos e protocolos anestésicos seguros para sua realização. Objetivaramse avaliar as possíveis alterações na freqüência cardíaca (FC), respiratória (FR), saturação de oxihemoglobina (SpO2) e temperatura retal (TR) durante a laparoscopia para visualização dos órgãos reprodutivos de seis fêmeas de veado-catingueiro (Mazama gouazoubira) anestesiadas com a associação cetamina (5mg/kg), xilazina (0,3mg/kg), midazolam (0,5mg/kg) e isofluorano. Cada animal, após anestesiado, foi posicionado em decúbito dorsal para realização de duas laparoscopias com insuflação abdominal de CO2 (14,2 ± 2,39mmHg; M ± EPM) com intervalo de 40 dias. Para avaliar os principais eventos da laparoscopia, esta foi dividida em três períodos: animal sem insuflação abdominal (P1), com insuflação abdominal (P2) e insuflação abdominal com os quadris elevados a 45º (P3). O controle foi realizado após 40 dias da última laparoscopia, para isto, cada animal foi novamente anestesiado e mantido em decúbito dorsal por um período de tempo igual ao tempo médio de duração das anestesias realizadas nas laparoscopias, sem que o procedimento laparoscópico fosse realizado. O tempo de anestesia dos controles foi também dividido em P1, P2 e P3, respeitando o tempo médio de duração de cada um destes períodos das laparoscopias. Para análise dos dados foi usado o teste de análise de variância (ANOVA) seguido do teste de Tukey e valores de P

Carbon dioxide (CO2) is the most commonly used insufflation gas to provide exposure in the abdominal cavity during laparoscopic surgery. This study investigated the results of hepatic and renal function tests after different capnoperitoneum intraabdominal pressures in dogs. Twenty-four beagle dogs (12 males and 12 females) were used (n = 6 dogs). The intraabdominal pressure was maintained for 60 minutes, and urinalysis, hepatic and renal function tests were carried out at designed times. No surgery was performed on any of the dogs during the capnoperitoneum. In this study, whether low or high pressure, significant increases of gamma-glutamyltransferase, alkaline phosphatase, aspartate aminotransferase and creatinine levels were observed after pneumoperitoneum. However, our results showed a trend toward higher serum concentrations of some enzymes in dogs at an insufflation pressure of 15 mmHg compared to that of the other groups, although these differences did not reach statistical significance. Therefore, low pressure capnoperitoneum should be considered for dogs with compromised splanchnic function, particularly those undergoing prolonged laparoscopic surgery. [ABSTRACT FROM AUTHOR]

Respiratory and cardiovascular changes in normocapnic dogs undergoing laparoscopic ovariectomy are described in this report. To-date, changes during a standardised ventilation pattern, irrespective of end-tidal CO2 (EtCO2) levels, have not been reported. This study was undertaken to describe these changes. Forty bitches undergoing laparoscopic ovariectomy were enrolled in a prospective double-blind randomised clinical trial. They were first anaesthetised with medetomidine-butorphanol-propofol and then maintained with isoflurane in oxygen- air. Ventilation pattern was pressure-controlled, volume-limited. After stabilisation, atracurium 0.4 mg/kg (ATR group, n = 20) or saline 0.04 ml/kg (SAL group, n = 20) was administered intravenously. Capnoperitoneum was then established with an intra-abdominal pressure setting of 10 mmHg. Collected data included heart rate (HR), non-invasive blood pressure, EtCO2, oxygen saturation of haemoglobin, and tidal volume and neuromuscular blockade (train-of-four). Data were recorded before administration of atracurium or saline, and at 2, 5, and 10 min thereafter. Subsequently, insufflation of CO2 was commenced. After capnoperitoneum was established, data were recorded at 2, 5 and 10 min. Time of capnoperitoneum induction and duration, time of ovary searching and excision and total time of capnoperitoneum and surgery were also recorded. For statistical analysis, the Shapiro Wilk test, ANOVA with repeated measures and Student's t-test for independent samples were used (P < 0.05). Significant increases in EtCO2 were observed in patients 5 min after atracurium administration and 5 min after capnoperitoneum was established in the ATR group, when compared to the SAL group. No other differences were found. Administration of atracurium in dogs undergoing laparoscopic ovariectomy with a standardised ventilation pattern did not result in clinically important differences in selected cardiovascular and respiratory variables and surgical times in comparison with non-relaxed dogs. Thus, the use of atracurium in laparoscopic ovariectomy does not result in any benefit for patients or surgeons. [ABSTRACT FROM AUTHOR]

Introduction: Operative time is an accepted risk factor for the development of postoperative ileus (POI). Innovative surgical procedures such as robotic surgery and natural orifice transluminal endoscopic surgery (NOTES) will be associated with longer operative times. Although intraabdominal manipulation is a major factor for POI the impact of prolonged capnoperitoneum on postoperative gastrointestinal transit time (GIT-TT) has rarely been studied. Material and methods: IRB approved survival pilot study to assess postoperative GIT-TT using fecal collection and chromium-oxide (Cr2O3) labeling in pigs. Twelve female pigs were randomly assigned to three groups of four animals each. Group A received eight hours anesthesia and pressure-controlled high flow capnoperitoneum (15 mmHg), group B eight hours of anesthesia only and group C no intervention. No intraoperative manipulation. The pilot study was terminated after eight days. Results: None of the animals developed POI. In Group A one animal died after eight hours of general anesthesia. No differences in postoperative fecal output, Cr2O3 excretion rate or weight gain were found. Conclusion: This study is the first to investigate eight hours of capnoperitoneum in a survival model. GIT-TT is not affected by prolonged capnoperitoneum in pigs. No POI occurred with prolonged capnoperitoneum. Prolonged capnoperitoneum is safe regarding postoperative gastrointestinal function in innovative surgical procedures. [ABSTRACT FROM AUTHOR]

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 HO 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 CO 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. [ABSTRACT FROM AUTHOR]

Objective To evaluate the influence of fentanyl on intra-abdominal pressures in spontaneously breathing dogs during capnoperitoneum. Study design Prospective clinical study. Animals Eleven healthy client-owned and five healthy experimental dogs undergoing laparoscopy. Methods Dogs were premedicated with acepromazine (0.03 mg kg−1 IV) and carprofen (4 mg kg−1 IV). Anaesthesia was induced with propofol and maintained with isoflurane in oxygen. The abdomen was insufflated with CO2 (11-16 cm H2O). Intra-abdominal pressures were measured with a transducer. Respiratory variables were measured with a spirometry sensor and side-stream capnography. Following preparation, fentanyl (1 μg kg−1) was injected over 30 seconds IV. Data were recorded 5 minutes before, during and 5 minutes after treatment. The following time points were selected for statistical analysis ( anova, p < 0.05): −160, −140, −120, −100, −80, −60, −40, −20, 0, 30, 50, 70, 90, 110, 130 and 150 seconds after the start of fentanyl injection. Results Intra-abdominal pressure increased during inspiration in 15 dogs but decreased in one dog. Fentanyl treatment did not alter these patterns. Peak inspiratory and end-expiratory intra-abdominal pressures continuously decreased over time during the whole experiment and fentanyl exaggerated the decrease in inspiratory pressures but did not affect the rate of decrease in expiratory pressures. Differences between intra-abdominal pressures were stable before, but decreased after fentanyl administration from 4.1 ± 1.4 to 3.3 ± 1.2 cm H2O (at 0 and 150 seconds time points). End-tidal CO2 partial pressures increased from 6.0 ± 0.8 to 6.6 ± 0.9 kPa, respiratory rate decreased from 10.8 ± 2.6 to 7.8 ± 2.2 breaths per minute and tidal volume decreased from 13.7 ± 4.4 to 12.4 ± 2.9 mL kg−1 after fentanyl but these variables did not change before fentanyl treatment. Airway pressures did not change. Conclusions and clinical relevance Fentanyl did not increase intra-abdominal pressures in dogs. [ABSTRACT FROM AUTHOR]

Laparoscopic surgery was introduced into clinical practice in the early 1950s by gynaecologists. Technical improvements allowed its use for more complex and longer lasting procedures. Reduction of postoperative pain, more favourable cosmetic results, quicker recovery and reduced length of hospital stay proved to be advantageous when compared to open surgery. As a result progressively older patients with corresponding pulmonary and cardiovascular comorbidities and morbidly obese patients are now undergoing advanced laparoscopic surgery. Detailed knowledge of the respiratory and hemodynamic pathophysiology induced by capnoperitoneum is necessary to administer safe anaesthesia to such patients. This review addresses the most important effects of capnoperitoneum and recent research as well as the possible implications for clinical practice. [ABSTRACT FROM AUTHOR]

Background Carbon dioxide (CO2) embolism is a possible complication of capnoperitoneum during laparoscopic surgery. Experimentally induced venous CO2 embolism has been studied in pigs. In this paper we report a case of spontaneous CO2 embolism. Observations A 4-month-old Large White pig weighing 20 kg underwent experimental laparoscopic surgery under general anaesthesia. Monitoring consisted of pulse oximetry, capnography, airway pressure, electrocardiography, invasive arterial and central venous blood pressures, and arterial blood-gas analysis. Shortly after the start of laparoscopy and onset of CO2 insufflation, sudden decreases in end-tidal CO2 (Pe′CO2), haemoglobin saturation of oxygen (SpO2), systolic arterial blood pressure and heart rate were observed. Airway pressure increased and pulmonary compliance decreased simultaneously. Insufflation was immediately discontinued and epinephrine (2 mg IV), atropine (0.5 mg IV) and a 50 mL bolus of a polygeline solution were administered without effect. At this time arterial blood-gas analysis revealed a pH of 7.29 and a PaCO2 of 6.8 kPa (51.2 mmHg); PaO2 was 26.6 kPa (199.5 mmHg). After 4 minutes asystole occurred. Conclusions The sudden decrease of Pe′CO2 and lung compliance combined with the sudden decrease in systolic blood pressure, heart rate and a poor response to resuscitation suggest a case of fatal gaseous venous embolism. [ABSTRACT FROM AUTHOR]

Hypovolemia after bowel preparation as well as capnoperitoneum (CP) may compromise hemodynamic function during laparoscopic colonic surgery. A fall in arterial pressure after induction of anesthesia is often answered by generous fluid administration, which might impair “fast-track” rehabilitation. Intraoperative assessment of the needed infusion volume is difficult because of a lack of data regarding the volume status in these patients. Nineteen patients scheduled for laparoscopic colonic surgery after bowel preparation were prospectively monitored using the PULSION COLD Z-021 system and central venous catheter. Intrathoracic blood volume index (ITBVI), mean arterial pressure (MAP), cardiac index (CI), central venous pressure (CVP), and heart rate (HR) were measured after induction of anesthesia (M1), during CP in head-down position with an intraabdominal pressure (IAP) of 20 mmHg (M2) and 12 mmHg (M3). Although MAP (87 mmHg), HR (64 min−1), and CVP (8 mmHg) were within normal ranges at the induction of surgery, ITBVI (834 ml m−2), and CI (2.66 l m−2) were decreased, indicating a relative hypovolemia. CP with 12 mmHg increased ITBVI ( p<0.05) and CI ( p<0.01), while an IAP of 20 mmHg reduced CI ( p<0.05) compared to 12 mmHg (M3). Mean infusion during the measurements was 1,355 ml. Combination of CP with 12 mmHg, head-down position, and infusion of 1,500 ml fluids compensated relative hypovolemia during colonic surgery. With conventional monitoring, intravascular volume status might be underestimated after traditional preoperative care. [ABSTRACT FROM AUTHOR]

Simple Summary: Keyhole surgery has become a very popular form of surgery in human and veterinary medicine because of its advantages in patient recovery and smaller incision sites. The disadvantages are side effects of high intra-abdominal pressures on the circulation system. Veterinary surgeons initially adapted guidelines from human medicine with pressure limits of 15 mmHg, although little is known about pressure limits in smaller sized patients and differences in species. Most surgeons already use smaller pressure limits but very few studies exist and guidelines are often based on personal experience. This study analyzes the pressure relationship in the abdomen during keyhole surgery for neutering in 59 cats by measuring the volume inflated and the pressure from 0 to 15 mmHg and compares it to previous study results in dogs. This study shows that, similar to dogs, the intra-abdominal pressure and the insufflated volume rise until a threshold of 6.44 mmHg is reached. After this point, the volume gain decreases and pressure rises exponentially with each additional insufflation. This means insufflation over 7 mmHg in cats will result in minimal gain and should be avoided. Laparoscopy is a growing field in veterinary medicine, although guidelines are lacking. The objective of this study was to evaluate the pressure–volume curve during capnoperitoneum in cats. A total of 59 female cats were scheduled for routine laparoscopy. Pressure and volume data were recorded and processed, and the yield point of the curve was calculated using a method based on a capacitor discharging function. For the remaining 40 cats, a linear-like pressure–volume curve was observed until a yield point with a mean cutoff pressure (COP) of 6.44 ± 1.7 mmHg (SD) (range, 2.72–13.00 mmHg) and a mean cutoff volume (COV) of 387 ± 144.35 mL (SD) (range, 178.84–968.43 mL) was reached. The mean mL/kg CO2 value in cats was 208 ± 34.69 mL/kg (range, 100.00–288.46 mL/kg). The COV correlated with COP and body weight but not with body condition score (BCS). COP correlated only with the COV. This study suggests that feline patients have a pressure–volume curve similar to that of canine patients, and the same pressure limit recommendations can be used for both species. After a yield point of 6.44 mmHg is reached, the increment in volume decreases exponentially as the intra-abdominal pressure (IAP) increases. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) is the most commonly used insufflation gas to provide exposure in the abdominal cavity during laparoscopic surgery. This study investigated the results of hepatic and renal function tests after different capnoperitoneum intraabdominal pressures in dogs. Twenty-four beagle dogs (12 males and 12 females) were used (n = 6 dogs). The intraabdominal pressure was maintained for 60 minutes, and urinalysis, hepatic and renal function tests were carried out at designed times. No surgery was performed on any of the dogs during the capnoperitoneum. In this study, whether low or high pressure, significant increases of gamma-glutamyltransferase, alkaline phosphatase, aspartate aminotransferase and creatinine levels were observed after pneumoperitoneum. However, our results showed a trend toward higher serum concentrations of some enzymes in dogs at an insufflation pressure of 15 mmHg compared to that of the other groups, although these differences did not reach statistical significance. Therefore, low pressure capnoperitoneum should be considered for dogs with compromised splanchnic function, particularly those undergoing prolonged laparoscopic surgery., (Copyright © 2015 Elsevier Ltd. All rights reserved.)