Efficacy and safety of three inflation methods of the laryngeal mask airway Ambu® Auraonce™: a randomized controlled study.

The laryngeal mask airway (LMA) is commonly used for airway management. Cuff hyperinflation has been associated with complications, poor ventilation and increased risk of gastric insufflation. This study was designed to determine the best cuff inflation method of AuraOnce™ LMA during bronchoscopy and EBUS (Endobronquial Ultrasound Bronchoscopy) procedure. We designed a Randomized controlled, doble-blind, clinical trial to compare the efficacy and safety of three cuff inflation methods of AuraOnce™ LMA. 210 consenting patients scheduled for EBUS procedure under general anesthesia, using AuraOnce™ LMA were randomized into three groups depending on cuff insufflation: residual volume (RV), half of the maximum volume (MV), unchanged volume (NV). Parameters regarding intracuff pressure (IP), airway leak pressure (OLP), leakage volume (LV) were assessed, as well as postoperative complications (PC). 201 (95.7%) patients completed the study. Mean IP differed between groups (MV: 59.4 ± 32.4 cm H2O; RV: 75.1 ± 21.1 cm H2O; NV: 83.1 ± 25.5 cmH20; P < 0.01). The incidence of IP > 60 cmH2O was lower in the MV group compared to the other two (MV: 20/65(30.8%); RV:47/69 (68.1%); NV 48/67 (71.6%); p < 0.01). The insertion success rate was 89,6% (180/201) at first attempt, with no difference between groups (p = 0.38). No difference between groups was found either for OLP (p = 0.53), LV (p = 0.26) and PC (p = 0.16). When a cuff manometer is not available, a partial inflation of AuraOnce™ LMA cuff using MV method allows to control intracuff pressure, with no significant changes of OLP and LV compared to RV and NV insufflation method.Registration clinical trial: NCT04769791.

The Effect of Prolonged Face Mask Ventilation on Gastric Insufflation: A Prospective Observational Study.

BACKGROUND: Pulmonary aspiration is a potentially lethal perioperative complication that can be precipitated by gastric insufflation. Face mask ventilation (FMV), a ubiquitous anesthetic procedure, can cause gastric insufflation. FMV with an inspiratory pressure of 15 cm H2O provides the best balance between adequate pulmonary ventilation and a low probability of gastric insufflation. There is no data about the effects of FMV > 120 seconds. OBJECTIVES: To investigate the effect of prolonged FMV on gastric insufflation. METHODS: We conducted a prospective observational study at a tertiary medical center with female patients who underwent oocyte retrieval surgery under general anesthesia FMV. Pre- and postoperative gastric ultrasound examinations measured the gastric antral cross-sectional area to detect gastric insufflation. Pressure-controlled FMV with an inspiratory pressure of 15 cm H2O was continued from the anesthesia induction until the end of the surgery. RESULTS: The study comprised 49 patients. Baseline preoperative gastric ultrasound demonstrated optimal and good image quality. All supine measurements were feasible. The median duration of FMV was 13 minutes (interquartile range 9-18). In the postoperative period, gastric insufflation was detected in only 2 of 49 patients (4.1%). There was no association between the duration of FMV and delta gastric antral cross-sectional area (ß -0.01; 95% confidence interval -0.04 to 0.01, P = 0.31). CONCLUSIONS: Pressure-controlled FMV with an inspiratory pressure of 15 cm H2O carries a low incidence of gastric insufflations, not only as a bridge to a definitive airway but as an alternative ventilation method for relatively short procedures in selective populations.

The Effect of Clonidine Premedication on Hemodynamic Changes Following Tracheal Intubation and Co2 Gas Insufflation and Postoperative Shivering In Patients Undergoing Laparoscopic Cholecystectomy; a Randomized Clinical Trial.

BACKGROUND: Laparoscopic cholecystectomy is a proper treatment for cholecystitis but the Carbon dioxide gas which is used in surgery stimulates the sympathetic system and causes hemodynamic changes and postoperative shivering in patients undergoing operations. This study was conducted to evaluate the effects of clonidine on reducing hemodynamic changes during tracheal intubation and Carbon dioxide gas insufflation and postoperative shivering in patients undergoing laparoscopic cholecystectomy. MATERIAL AND METHODS: This prospective, randomized, triple-blind clinical trial was conducted on 60 patients between the 18-70 years-old age group, who were candidates of laparoscopic cholecystectomy surgery. The patients randomized into two groups (30 patients received 150 µg oral clonidine) and 30 patients received 100 mg oral Vitamin C). Heart rate and mean arterial pressure of patients were recorded before anesthesia, before and after laryngoscopy, before and after Carbon dioxide gas insufflation. Data were analyzed using Chi-2, student t-test, and analysis of variance by repeated measure considering at a significant level less than 0.05. RESULTS: The findings of this study showed that both heart rate and mean arterial pressure in clonidine group after tracheal intubation and Carbon dioxide gas insufflation were lower than patients in the placebo group, but there was not any statistically significant difference between the two groups (p>0.05) and also postoperative shivering was not different in groups. There was no significant statistical difference in postoperative shivering between the two groups (p>0.05). CONCLUSION: Using 150 µg oral clonidine as a cheap and affordable premedication in patients undergoing laparoscopic cholecystectomy improves hemodynamic stability during operation.

Transnasal Humidified Rapid Insufflation Ventilatory Exchange Augments Oxygenation in Children With Juvenile Onset Recurrent Respiratory Papillomatosis During Surgery: A Prospective Randomized Crossover Controlled Trial.

BACKGROUND: Evidence is lacking regarding the efficacy of transnasal humidified rapid insufflation ventilatory exchange (THRIVE) in tubeless anesthesia, especially in pediatric patients. This study aimed to evaluate the use of THRIVE for juvenile onset recurrent respiratory papillomatosis (JORRP) patients. METHODS: Twenty-eight children aged 2 to 12 years with JORRP, abnormal airways, and ASA physical status II-III that presented for surgical treatment under general anesthesia were included in this study. Each patient received 2 interventions in random order, with a 5-minute washout period between treatments: apnea without oxygen supplementation and apnea with THRIVE intervention. The primary outcome apnea time was defined as the duration from withdrawal of intubation to reintubation and resumption of controlled ventilation. The secondary outcomes were the mean transcutaneous carbon dioxide (tc co2 ) increase rate, the minimum pulse oxygen saturation (Sp o2 ) during apnea, and the occurrence of unexpected adverse effects. RESULTS: The median apnea time in the THRIVE period was significantly longer than that in the control period (8.9 [8.6-9.4] vs 3.8 [3.4-4.3] minutes; mean difference [95% confidence interval (CI)], 5.0 [4.4-5.6]; P < .001) for all patients. The rate of CO 2 change in the control period was higher than that in the THRIVE period both for patients aged 2 to 5 years old (6.29 [5.19-7.4] vs 3.22 [2.92-3.76] mm Hg min -1 ; mean difference [95% CI], 3.09 [2.27-3.67]; P < .001) and for patients aged 6 to 12 years old (4.76 [3.7-6.2] vs 3.38 [2.64-4.0] mm Hg min -1 ; mean difference [95% CI], 1.63 [0.75-2.56]; P < .001). The minimum Sp o2 was significantly higher in the THRIVE period than in the control period (mean difference [95% CI], 19.7 [14.8-22.6]; P < .001). CONCLUSIONS: Our findings demonstrate that THRIVE safely increased the apnea time among children with JORRP undergoing surgery and decreased the rate of carbon dioxide increase. THRIVE is clinically recommended as an airway management technique for tubeless anesthesia in apneic children.

Mechanical Insufflation-Exsufflation: The Rest of the Story.

Mechanical insufflation-exsufflation has been reported to decrease pneumonia rates by about 90% for patients with Duchenne muscular dystrophy now living into their 40s and 50s without tracheotomy tubes. It greatly reduces respiratory complications and hospitalization rates to less than one per 10 patient-years for advanced spinal muscular atrophy type 1, through 25-30 years of age. It is most successful from the point at which small children become able to cooperate with it, generally from 3 to 5 years of age. However, since the 1950s, successful use to extubate and decannulate ventilator "unweanable" patients with little to no measurable vital capacity without resorting to tracheostomy has always been at pressures of 50-60 cm H2O via oronasal interfaces and at 60-70 cm H2O via airway tubes when present. It must usually also be used in conjunction with up to continuous noninvasive positive pressure ventilatory support. Centers that use these effectively have eliminated need to resort to tracheotomies for people with muscular dystrophies and spinal muscular atrophies, including unmedicated patients with spinal muscular atrophy type 1. Barotrauma has been rare despite dependence on it and noninvasive ventilatory support. Despite this, noninvasive respiratory management continues to be widely underutilized.

Effect of transnasal humidified rapid-insufflation ventilatory exchange on gastric insufflation during anaesthesia induction: A randomised controlled trial and multivariate analysis.

BACKGROUND: Mask ventilation during anaesthesia induction is generally used to provide adequate oxygenation but improper mask ventilation can result in gastric insufflation. It has been reported that oxygen administered by transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) during anaesthesia induction can maintain oxygenation but its effect on gastric insufflation is unknown. OBJECTIVES: The primary aim of this study was to evaluate whether THRIVE provided adequate oxygenation without gastric insufflation. The secondary aim was to explore the change in cross-sectional area of the antrum (CSAa) during anaesthesia induction. Other potential risk factors of gastric insufflation were also explored. DESIGN: A prospective, randomised, double-blind study. SETTING: Single centre, Department of Anaesthesiology, 1 st Affiliated Hospital, Wenzhou Medical University, China, from May 2022 to September 2022. PATIENTS: A total of 210 patients (age >18 years, ASA classification I to III) scheduled to undergo general anaesthesia were enrolled. INTERVENTIONS: For induction of general anaesthesia, patients were randomised into two groups: THRIVE and pressure-controlled facemask ventilation (PCFV). The THRIVE group received high-flow nasal oxygen with no additional ventilation. The PCFV group had pressure-controlled positive pressure ventilation from the anaesthesia machine via a tight fitting facemask. Gastric insufflation was detected using real-time ultrasonography. The CSAa was measured from ultrasonography images obtained before anaesthesia induction and at 0, 1, 2 and 3 min after loss of consciousness. MAIN OUTCOME MEASURES: The incidence of gastric insufflation during the period from loss of consciousness until intubation. RESULTS: The THRIVE group had a lower incidence of gastric insufflation during anaesthesia induction than the PCFV group (13.0 vs. 35.3%, odds ratio (OR) = 0.27, 95% confidence interval (CI), 0.14 to 0.56, P  < 0.001). Increase in the CSA after anaesthesia induction was significantly correlated with gastric insufflation (OR = 5.35, 95% CI, 2.90 to 9.89, P  < 0.001). Multivariate logistic regression analysis showed that advancing age (OR = 1.04, 95% CI, 1.01 to 1.07), obstructive sleep apnoea syndrome (OR = 2.43, 95% CI, 1.24 to 4.76), higher Mallampati score (OR = 2.66, 95% CI, 1.21 to 5.85) and PCFV (OR = 4.78, 95% CI, 2.06 to 11.06) were important independent risk factors for gastric insufflation. CONCLUSION: During anaesthesia induction, the THRIVE technique provided adequate oxygenation with a reduced incidence of gastric insufflation. PCFV, advancing age, obstructive sleep apnoea syndrome and the Mallampati score were found to be independent risk factors for gastric insufflation during anaesthesia induction. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR200059555.

A prospective randomized controlled trial of the safety and efficacy of carbon dioxide insufflation compared with room air insufflation during gastric endoscopic submucosal dissection.

BACKGROUND AND AIM: Carbon dioxide (CO2 ) insufflation during gastric endoscopic submucosal dissection (GESD) under sedation can be used instead of room air insufflation. Appropriate monitoring of the partial pressure of CO2 during GESD is necessary due to the impaired respiration. The aim of this study was to assess the safety and efficacy of CO2 insufflation during GESD compared with conventional room air insufflation. METHODS: Patients with a gastric epithelial neoplasm or early gastric cancer were enrolled. A total of 76 consecutive patients were randomly assigned to the CO2 insufflation group (CO2 group) or the room air insufflation group (air group). The primary outcome was the mean difference of end-tidal CO2 (EtCO2 ) between two groups. RESULTS: The upper bound of the 95% CI for the mean EtCO2 difference between the two groups before the procedure and at 15, 30 and 45 min after insufflation met the criteria for noninferiority. In a subgroup analysis of patients 70 years and older, the mean difference of EtCO2 was not significantly different between two groups. However, the air group received more analgesics than the CO2 group after the procedure (67.6% vs 35.1%, P = 0.005). In addition, in terms of improvement of abdominal pain or bowel gas after 24 h of GESD, CO2 group showed better results than air group (both P < 0.05). CONCLUSIONS: CO2 insufflation during GESD is as safe as using room air, and patients, including elderly patients, receiving CO2 achieve more rapid relief of abdominal pain and intra-abdominal residual gas during and after the procedure.

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

BACKGROUND AND AIMS: This experimental study assesses the influence of different gases and insufflation pressures on the portal, central-venous and peripheral-arterial pH during experimental laparoscopy. METHODS: Firstly, 36 male WAG/Rij rats were randomized into six groups (n = 6) spontaneously breathing during anaesthesia: laparoscopy using carbon dioxide or helium at 6 and 12 mmHg, gasless laparoscopy and laparotomy. 45 and 90 min after setup, blood was sampled from the portal vein, vena cava and the common femoral artery with immediate blood gas analysis. Secondly, 12 animals were mechanically ventilated at physiological arterial pH during 90 min of laparotomy (n = 6) or carbon dioxide laparoscopy at 12 mmHg (n = 6) with respective blood gas analyses. RESULTS: Over time, in spontaneously breathing rats, carbon dioxide laparoscopy caused significant insufflation pressure-dependent portal acidosis (pH at 6 mmHg, 6.99 [6.95-7.04] at 45 min and 6.95 [6.94-6.96] at 90 min, pH at 12 mmHg, 6.89 [6.82-6.90] at 45 min and 6.84 [6.81-6.87] at 90 min; p < 0.05) compared to laparotomy (portal pH 7.29 [7.23-7.30] at 45 min and 7.29 [7.20-7.30] at 90 min; p > 0.05). Central-venous and peripheral-arterial acidosis was significant but less severely reduced during carbon dioxide laparoscopy. Laparotomy, helium laparoscopy and gasless laparoscopy showed no comparable acidosis in all vessels. Portal and central-venous acidosis during carbon dioxide laparoscopy at 12 mmHg was not reversible by mechanical hyperventilation maintaining a physiological arterial pH (pH portal 6.85 [6.84-6.90] (p = 0.004), central-venous 6.93 [6.90-6.99] (p = 0.004), peripheral-arterial 7.29 [7.29-7.31] (p = 0.220) at 90 min; Wilcoxon-Mann-Whitney test). CONCLUSION: Carbon dioxide laparoscopy led to insufflation pressure-dependent severe portal and less severe central-venous acidosis not reversible by mechanical hyperventilation.

Preperitoneal insufflation pressure of the abdominal wall in a porcine model.

BACKGROUND: Most complications and adverse events during laparoscopic surgery occur during initial entry into the peritoneal cavity. Among them, preperitoneal insufflation occurs when the insufflation needle is incorrectly placed, and the abdominal wall is insufflated. The objective of this study was to find a range for static pressure which is low enough to allow placement of a Veress needle into the peritoneal space without causing preperitoneal insufflation, yet high enough to separate abdominal viscera from the parietal peritoneum. METHODS: A pressure test was performed on twelve fresh porcine carcasses to determine the minimum preperitoneal insufflation pressure and the minimum initial peritoneal cavity insufflation pressure. Each porcine model had five needle placement categories. One category tested the initial peritoneal cavity insufflation pressure beneath the umbilicus. The four remaining categories tested the preperitoneal insufflation pressure at four different anatomical locations on the abdomen that can be used for initial entry. The minimum initial insufflation pressures from each carcass were then compared to the preperitoneal insufflation pressures to obtain an optimal range for initial insufflation. RESULTS: Increasing the insufflation pressure increased the probability of preperitoneal insufflation. Also, there was a statistically significant difference (p < 0.05) between the initial peritoneal cavity insufflation pressures (8.83 ± 4.19 mmHg) and the lowest preperitoneal pressures (32.54 ± 7.84 mmHg) (mean ± SD). CONCLUSION: Pressures greater than 10 mmHg resulted in initial cavity insufflation and pressures greater than 20 mmHg resulted in preperitoneal insufflation in porcine models. By knowing the minimum pressure required to separate the layers of the abdominal wall, the risk of preperitoneal insufflation can be mitigated while obtaining safe and efficient entry into the peritoneal cavity. The findings in this research are not a guideline for trocar or Veress needle placement, but instead reveal preliminary data which may lead to more studies, technology, etc.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery.

BACKGROUND: This is the second update of a Cochrane Review first published in 2013 and last updated in 2017. Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum. OBJECTIVES: To assess the safety, benefits, and harms of different gases (e.g. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic abdominal or gynaecological pelvic surgery. SEARCH METHODS: We searched CENTRAL, Ovid MEDLINE, Ovid Embase, four other databases, and three trials registers on 15 October 2021 together with reference checking, citation searching, and contact with study authors to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included 10 RCTs, randomising 583 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (four trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. All the RCTs were single-centre studies. Four RCTs were conducted in the USA; two in Australia; one in China; one in Finland; one in Iran; and one in the Netherlands. The mean age of the participants ranged from 27.6 years to 49.0 years. Four trials randomised participants to nitrous oxide pneumoperitoneum (132 participants) or carbon dioxide pneumoperitoneum (128 participants). None of the trials was at low risk of bias. The evidence is very uncertain about the effects of nitrous oxide pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto odds ratio (OR) 2.62, 95% CI 0.78 to 8.85; 3 studies, 204 participants; very low-certainty evidence), or surgical morbidity (Peto OR 1.01, 95% CI 0.14 to 7.31; 3 studies, 207 participants; very low-certainty evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (4 studies, 260 participants; very low-certainty evidence). Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. The evidence is very uncertain about the effects of helium pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto OR 1.66, 95% CI 0.28 to 9.72; 3 studies, 128 participants; very low-certainty evidence), or surgical morbidity (5 studies, 177 participants; very low-certainty evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (3 studies, 128 participants; very low-certainty evidence). One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at high risk of bias. There were no cardiopulmonary complications, serious adverse events, or deaths observed related to either room air or carbon dioxide pneumoperitoneum.    AUTHORS' CONCLUSIONS: The evidence is very uncertain about the effects of nitrous oxide, helium, and room air pneumoperitoneum compared to carbon dioxide pneumoperitoneum on any of the primary outcomes, including cardiopulmonary complications, surgical morbidity, and serious adverse events. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established, especially in people with high anaesthetic risk.

Incidence of gastric insufflation at high compared with low laryngeal mask cuff pressure: A randomised controlled cross-over trial.

BACKGROUND: The success of ventilation with a laryngeal mask depends crucially on the seal between the mask and the periglottic tissue. Increasing the laryngeal mask's cuff volume is known to reduce oral air leakage but may lead to gastric insufflation. OBJECTIVE: We hypothesised that a lower cuff pressure would result in less gastric insufflation. We sought to compare gastric insufflation with laryngeal mask cuff pressures of 20 cmH2O (CP20) and 60 cmH2O (CP60) during increasing peak airway pressures in a randomised controlled double-blind cross-over study. We also evaluated the incidence of gastric insufflation at the recommended peak airway pressure of 20 cmH2O or less and during both intermittent positive airway pressure and continuous positive airway pressure. METHODS: After obtaining ethics approval and written informed consent, 184 patients ventilated via laryngeal mask received a stepwise increase in peak airway pressure from 15 to 30 cmH2O with CP20 and CP60 in turn. Gastric insufflation was determined via real-time ultrasound and measurement of the cross-sectional area of the gastric antrum. The primary endpoint was the incidence of gastric insufflation at the different laryngeal mask cuff pressures. RESULTS: Data from 164 patients were analysed. Gastric insufflation occurred less frequently at CP20 compared with CP60 (P < 0.0001). Gastric insufflation was detected in 35% of cases with CP20 and in 48% with CP60 at a peak airway pressure of 20 cmH2O or less. Gastric insufflation occurred more often during continuous than during intermittent positive airway pressures (P < 0.01). CONCLUSION: A laryngeal mask cuff pressure of 20 cmH2O may reduce the risk of gastric insufflation during mechanical ventilation. Surprisingly, peak airway pressure of 20 cmH2O or less may already induce significant gastric insufflation. Continuous positive airway pressure should be avoided due to an increased risk of gastric insufflation. CLINICAL TRIAL REGISTRATION: The study was registered in the German Clinical Trials Register (DRKS00010583) https://www.drks.de.

Postpyloric Balloon Occlusion to Increase Technical Success during Pediatric Percutaneous Gastrostomy/Gastrojejunostomy Tube Placement.

Gastric distension through insufflation is a key step in creating a safe percutaneous window during gastrostomy/gastrojejunostomy (G/GJ) placement; however, poor or incomplete gastric distention can occur, despite the use of glucagon, and lead to rapid egress of air from the stomach into the duodenum. This report describes the adjunctive technique using postpyloric balloon occlusion in 29 patients to maximize gastric insufflation during G/GJ tube placement after failure of conventional methods. Balloon occlusion was successful in salvaging 23 of 29 (79.3%) of G/GJ tube placements without any complications.

Efficacy and Safety of Carbon Dioxide Versus Air Insufflation for Colonoscopy in Deeply Sedated Pediatric Patients.

OBJECTIVES: Studies have shown the advantages of carbon dioxide (CO2) over air insufflation in the adult population during colonoscopies. This study was designed to investigate the efficacy and safety of CO2 insufflation in deeply sedated children undergoing colonoscopy. METHODS: This was a prospective, randomized, double-blind clinical trial. We recruited 100 consecutive pediatric patients who had colonoscopy under deep sedation for various indications. Patients were first randomized by history of abdominal pain and then randomly assigned to either CO2 or air insufflation. Postprocedural abdominal pain scores were registered on a 10-point visual analog rating scale and significant pain was defined as a score of 3 or higher. Abdominal circumferences and end tidal CO2 (ETCO2) levels were measured. Complications during and after the procedure were recorded. RESULTS: We did not find statistically significant difference between CO2 and air insufflation on univariate analysis because of low number of children experiencing significant pain after colonoscopy. After adjusting for baseline pain, we found that pain was significantly lower in patients after CO2 versus air insufflation on multivariable analysis (P = 0.03). The significant factors related to pain were duration of the procedure (P = 0.006), history of abdominal pain (P = 0.002) and previous abdominal surgery (P = 0.02). CO2 insufflation was associated with decreased abdominal circumference after colonoscopy (P = 0.002). Girls were more likely to have pain regardless of intervention (P = .04). CONCLUSIONS: Most children tolerate endoscopic procedures without significant pain. Our study was underpowered to show significant difference between air and CO2 on univariate analysis. CO2 insufflation during colonoscopy, however, may reduce postprocedural abdominal pain. Significant factors for increased pain on multivariate analysis included colonoscopy length over 30 minutes, history of abdominal pain, and previous abdominal surgery.

Transthoracic echocardiography-monitored CO2-insufflation esophageal endoscopy for diagnosis of Atrioesophageal fistula and prevention of iatrogenic air embolism: a case report.

BACKGROUND: Atrioesophageal fistula (AEF) is the most fatal complication associated with catheter ablation for atrial fibrillation and cannot be easily detected when thoracic contrast-enhanced computed tomography (CT) is normal. CASE PRESENTATION: In this report, we described a diagnostic tool for detecting AEF with doubtful chest CT in which we introduced CO2-insufflation esophageal endoscopy with transthoracic echocardiography monitoring. Using this modified esophageal endoscopy, AEF was established due to the presence of both esophageal lesions and bubbles into the left atrium. That way, our patient accepted to be operated in time with good clinical prognosis. CONCLUSIONS: This modified esophageal endoscopy is an alternative tool for early detection of AEF when normal or doubtful CT findings present.

Gentle facemask ventilation during induction of anesthesia.

BACKGROUND: To determine the level of inspiratory pressure minimizing the risk of gastric insufflation while providing adequate pulmonary ventilation. METHODS: In this prospective, randomized, double-blind study, patients were allocated to one of the two groups (P10, P15) defined by the inspiratory pressure applied during controlled-pressure ventilation: 10 and 15 cm H2O. Anesthesia was induced using propofol and sufentanil; no neuromuscular-blocking agent was administered. Once loss of eyelash reflex occurred, facemask ventilation was started for a 2-min period. The cross-sectional antral area was measured using ultrasonography before and after facemask ventilation. Respiratory parameters were recorded. RESULTS: Forty patients were analyzed. Mean tidal volume was about 7 ml/kg in group P10, and was >11 ml/kg in group P15 in the same period. As indicated by ultrasonography test, the antral area in P15 group was markedly incresed compared with P10 group. CONCLUSION: Inspiratory pressure of 10 cm H2O allowed for reduced occurrence of gastric insufflation with proper lung ventilation during induction of anesthesia with sufentanil and propofol in nonparalyzed and nonobese patients.

Comparison of Carbon Dioxide Absorption Rates in Gynecologic Laparoscopy with a Valveless versus Standard Insufflation System: Randomized Controlled Trial.

STUDY OBJECTIVE: The primary objective was to compare carbon dioxide (CO2) absorption rates in patients undergoing gynecologic laparoscopy with a standard versus valveless insufflation system (AirSeal; ConMed, Utica, NY) at intra-abdominal pressures (IAPs) of 10 and 15 mm Hg. Secondary objectives were assessment of surgeons' visualization of the operative field, anesthesiologists' ability to maintain adequate end-tidal CO2 (etCO2), and patients' report of postoperative shoulder pain. DESIGN: A randomized controlled trial using an equal allocation ratio into 4 arms: standard insufflation/IAP 10 mm Hg, standard insufflation/IAP 15 mm Hg, valveless insufflation/IAP 10 mm Hg, and valveless insufflation/IAP 15 mm Hg. SETTING: Single tertiary care academic institution. PATIENTS: Women ≥ 18 years old undergoing nonemergent conventional or robotic gynecologic laparoscopic surgery. INTERVENTIONS: A standard or valveless insufflation system at IAPs of 10 or 15 mm Hg. MEASUREMENTS AND MAIN RESULTS: One hundred thirty-two patients were enrolled and randomized with 33 patients per group. There were 84 robotic cases and 47 conventional laparoscopic cases. CO2 absorption rates (mL/kg*min) did not differ across groups with mean rates of 4.00 ± 1.3 in the valveless insufflation groups and 4.00 ± 1.1 in the standard insufflation groups. The surgeons' rating of overall visualization of the operative field on a 10-point Likert scale favored the valveless insufflation system (median visualization, 9.0 ± 2.0 cm and 9.5 ± 1.8 cm at 10 and 15 mm Hg, respectively) over standard insufflation (7.0 ± 3.0 cm and 7.0 ± 2.0 cm at 10 and 15 mm Hg, respectively; p <.001). The anesthesiologists' ability to maintain adequate etCO2 was similar across groups (p = .417). Postoperative shoulder pain scores were low overall with no significant difference across groups (p >.05). CONCLUSION: CO2 absorption rates, anesthesiologists' ability to maintain adequate etCO2, and postoperative shoulder pain did not differ based on insufflation system type or IAP. Surgeons' rating of visualization of the operative field was significantly improved when using the valveless over the standard insufflation system.

The AirSeal® insufflation device can entrain room air during routine operation.

BACKGROUND: Surgical procedures that use insufflation carry a risk of gas embolism, which is considered relatively harmless because of the high solubility of carbon dioxide. However, an in vitro study suggested that valveless insufflation devices may entrain non-medical room air into the surgical cavity. Our aim was to verify if this occurs in actual surgical procedures. METHODS: The oxygen percentage in the pneumoperitoneum or pneumorectum/pneumopelvis of eight patients operated with use of the AirSeal® was continuously measured, to determine the percentage of air in the total volume of the surgical cavity. RESULTS: Basal air percentage in the surgical cavity was 0-5%. During suctioning from the operative field air percentage increased to 45-65%. CONCLUSIONS: The AirSeal® valveless insufflation device maintains optimal distension of the surgical cavity not only by insufflating carbon dioxide, but also by entraining room air, especially during suctioning from the operative field. This may theoretically lead to air embolism in patients operated on with this device.

Efficacy and safety of water-exchange enteroscopy compared to carbon dioxide insufflation during enteroscopy.

INTRODUCTION: carbon dioxide (CO2) insufflation during enteroscopy reduces procedure time and subsequent symptoms and increases the insertion depth compared with room air. In colonoscopy, the water-exchange (WE) technique is associated with less pain compared with CO2 insufflation. The WE technique is not well studied in enteroscopy. The aim of this study was to compare the efficacy and safety of enteroscopy with WE and CO2. METHODS: a prospective, comparative and observational study was performed of double balloon enteroscopies (DBE) that were randomized in two groups. The first group used WE while the second group used CO2 insufflation. The data collected was evaluated via univariate analysis and multiple logistic regression (variables with p ≤ 0.10 according to the univariate analysis). RESULTS: forty-six DBE were included; 23 in each arm. The median age of cases was 63.5 years and 37% were female. There were no statistical differences between the groups with regard to the access route, findings, therapy and complications. Four patients (20%) in the CO2 group had adverse events (abdominal distension and pain) and one in the WE group (nausea), which was not statistically significant. The median insertion depth was greater in the CO2 group; 260 cm vs 160 cm (p = 0.048). Multiple logistic regression showed a statistically significant difference in the insertion depth using CO2 insufflation (OR 1.009, 1.001-1.017; p = 0.034). CONCLUSIONS: DBE with a CO2 insufflation technique and WE are safe with a greater insertion depth with CO2.

Pneumomediastinum, subcutaneous emphysema and pneumorrhachis following cocaine insufflation: a case report.

A case report on a 36-year-old male patient presenting to the emergency department (ED) with chest tightness, nasal sounding voice and subcutaneous emphysema 72 hours after the nasal insufflation of approximately 0.5g of cocaine. A plain radiograph of the chest demonstrated an extensive pneumomediastinum with subcutaneous emphysema extending into his neck. A computerised tomography (CT) scan confirmed the above findings, along with a pneumorrhachis of the thoracic spine. He was admitted locally for further investigation and observation. Cocaine is the second most used illicit drug in the UK. The associated complications of cocaine can vary from acute coronary syndrome to acute psychosis. Pulmonological trauma secondary to cocaine misuse is commonly associated with inhalation of cocaine; we present this rare case of subcutaneous emphysema, pneumomediastinum and pneumorrhachis secondary to nasal insufflation. It is believed that deep nasal insufflation of cocaine is followed by forceful Valsalva manoeuvre, which allows for the rapid absorption of the drug and increases the euphoric effect. This forceful inhalation can lead to barotrauma and leakage of air into the posterior mediastinum.

Carbon Dioxide Embolism Associated With Transanal Total Mesorectal Excision Surgery: A Report From the International Registries.

BACKGROUND: Carbon dioxide embolus has been reported as a rare but clinically important risk associated with transanal total mesorectal excision surgery. To date, there exists limited data describing the incidence, risk factors, and management of carbon dioxide embolus in transanal total mesorectal excision. OBJECTIVE: This study aimed to obtain data from the transanal total mesorectal excision registries to identify trends and potential risk factors for carbon dioxide embolus specific to this surgical technique. DESIGN: Contributors to both the LOREC and OSTRiCh transanal total mesorectal excision registries were invited to report their incidence of carbon dioxide embolus. Case report forms were collected detailing the patient-specific and technical factors of each event. SETTINGS: The study was conducted at the collaborating centers from the international transanal total mesorectal excision registries. MAIN OUTCOME MEASURES: Characteristics and outcomes of patients with carbon dioxide embolus associated with transanal mesorectal excision were measured. RESULTS: Twenty-five cases were reported. The incidence of carbon dioxide embolus during transanal total mesorectal excision is estimated to be ≈0.4% (25/6375 cases). A fall in end tidal carbon dioxide was noted as the initial feature in 22 cases, with 13 (52%) developing signs of hemodynamic compromise. All of the events occurred in the transanal component of dissection, with mean (range) insufflation pressures of 15 mm Hg (12-20 mm Hg). Patients were predominantly (68%) in a Trendelenburg position, between 30° and 45°. Venous bleeding was reported in 20 cases at the time of carbon dioxide embolus, with periprostatic veins documented as the most common site (40%). After carbon dioxide embolus, 84% of cases were completed after hemodynamic stabilization. Two patients required cardiopulmonary resuscitation because of cardiovascular collapse. There were no deaths. LIMITATIONS: This is a retrospective study surveying reported outcomes by surgeons and anesthetists. CONCLUSIONS: Surgeons undertaking transanal total mesorectal excision must be aware of the possibility of carbon dioxide embolus and its potential risk factors, including venous bleeding (wrong plane surgery), high insufflation pressures, and patient positioning. Prompt recognition and management can limit the clinical impact of such events. See Video Abstract at http://links.lww.com/DCR/A961.