Gastric insufflation and surgical view according to mask ventilation method for laparoscopic cholecystectomy: a randomized controlled study.

BACKGROUND: Proper mask ventilation is important to prevent air inflow into the stomach during induction of general anesthesia, and it is difficult to send airflow only through the trachea without gastric inflation. Changes in gastric insufflation according to mask ventilation during anesthesia induction were compared. METHODS: In this prospective, randomized, single-blind study, 230 patients were analyzed to a facemask-ventilated group (Ventilation group) or no-ventilation group (Apnea group) during anesthesia induction. After loss of consciousness, pressure-controlled ventilation at an inspiratory pressure of 15 cmH2O was performed for two minutes with a two-handed mask-hold technique for Ventilation group. For Apnea group, only the facemask was fitted to the face for one minute with no ventilation. Next, endotracheal intubation was performed. The gastric cross-sectional area (CSA, cm2) was measured using ultrasound before and after induction. After pneumoperitoneum with carbon dioxide, gastric insufflation of the surgical view was graded by the surgeon for each group. RESULTS: Increase of postinduction antral CSA on ultrasound were not significantly different between Ventilation group and Apnea group (0.04 ± 0.3 and 0.02 ± 0.28, p-value = 0.225). Additionally, there were no significant differences between the two groups in surgical grade according to surgeon's judgement. CONCLUSIONS: Pressure-controlled ventilation at an inspiratory pressure of 15 cmH2O for two minutes did not increase gastric antral CSA and insufflation of stomach by laparoscopic view. TRIAL REGISTRATION: http://cris.nih.go.kr (KCT0003620) on 13/3/2019.

Gastric Point-of-Care Ultrasound in Acutely and Critically Ill Children (POCUS-ped): A Scoping Review.

Introduction: Point-of-care ultrasound (POCUS) use is increasing in pediatric clinical settings. However, gastric POCUS is rarely used, despite its potential value in optimizing the diagnosis and management in several clinical scenarios (i.e., assessing gastric emptying and gastric volume/content, gastric foreign bodies, confirming nasogastric tube placement, and hypertrophic pyloric stenosis). This review aimed to assess how gastric POCUS may be used in acute and critically ill children. Materials and Methods: An international expert group was established, composed of pediatricians, pediatric intensivists, anesthesiologists, radiologists, nurses, and a methodologist. A scoping review was conducted with an aim to describe the use of gastric POCUS in pediatrics in acute and critical care settings. A literature search was conducted in three databases, to identify studies published between 1998 and 2022. Abstracts and relevant full texts were screened for eligibility, and data were extracted, according to the JBI methodology (Johanna Briggs Institute). Results: A total of 70 studies were included. Most studies (n = 47; 67%) were conducted to assess gastric emptying and gastric volume/contents. The studies assessed gastric volume, the impact of different feed types (breast milk, fortifiers, and thickeners) and feed administration modes on gastric emptying, and gastric volume/content prior to sedation or anesthesia or during surgery. Other studies described the use of gastric POCUS in foreign body ingestion (n = 6), nasogastric tube placement (n = 5), hypertrophic pyloric stenosis (n = 8), and gastric insufflation during mechanical ventilatory support (n = 4). POCUS was performed by neonatologists, anesthesiologists, emergency department physicians, and surgeons. Their learning curve was rapid, and the accuracy was high when compared to that of the ultrasound performed by radiologists (RADUS) or other gold standards (e.g., endoscopy, radiography, and MRI). No study conducted in critically ill children was found apart from that in neonatal intensive care in preterms. Discussion: Gastric POCUS appears useful and reliable in a variety of pediatric clinical settings. It may help optimize induction in emergency sedation/anesthesia, diagnose foreign bodies and hypertrophic pyloric stenosis, and assist in confirming nasogastric tube placement, avoiding delays in obtaining confirmatory examinations (RADUS, x-rays, etc.) and reducing radiation exposure. It may be useful in pediatric intensive care but requires further investigation.

Evaluation of adequacy of ventilation and gastric insufflation at three levels of inspiratory pressure for facemask ventilation during induction of anaesthesia: A randomised controlled trial.

BACKGROUND: In this study, we aimed to compare three inspiratory pressures during facemask ventilation in paralysed patients regarding the subsequent incidence of gastric insufflation and the adequacy of lung ventilation. METHODS: In this randomised controlled trial, we included adult patients undergoing elective surgery under general anaesthesia. The patients were randomly allocated to receive positive inspiratory pressure (PIP) of 10, 15, or 20 cmH2O during pressure-controlled mask ventilation. Antral cross-sectional area (CSA) was assessed by ultrasound at baseline before mask ventilation and after endotracheal intubation and gastric insufflation was defined as increased CSA after endotracheal intubation > 30% of the baseline measurement. The primary outcome was the incidence of gastric insufflation. Other outcomes included the tidal volume, and the incidence of adequate ventilation (tidal volume of 6-10 mL/kg predicted body weight). RESULTS: We analysed data from 36 patients in each group. The number of patients with gastric insufflation was the lowest in the PIP 10 group (0/36 [0%]) in comparison with PIP 15 (2/36 [19%] and PIP 20 36/36 [100%] groups (P-values of 0.019 and < 0.001, respectively). The probability of adequate ventilation at any time point was the highest in PIP 10, followed by PIP 15, and was the lowest in the PIP 20 group. CONCLUSION: An inspiratory pressure of 10 cmH2O in paralysed patients provided the least risk of gastric insufflation with adequate ventilation during induction of general anaesthesia compared to inspiratory pressure of 15- and 20 cmH2O.

Comparison of Effectiveness of CE Technique and Jaw Thrust Technique for Mask Ventilation on Apneic Anesthetized Adults: A Randomized Controlled Trial.

Background: The two most common techniques for mask ventilation are CE and jaw thrust (JT) technique. However, few studies have validated their efficiency in terms of tidal volume (TV). Aims: This study aimed to compare the effectiveness of the CE technique and JT technique during pressure-controlled ventilation (PCV) by the mean of returned TV on apneic anesthetized adults. Design: This was a prospective, randomized cross over study. Settings: This study was conducted in a tertiary care hospital. Methods: Ethical Committee approval from our institution was taken (ss-1/EC 049/2017) and was registered in Clinical Trials Registry of India (CTRI/2018/04/012958). Sixty-five American Society of Anesthesiologists Physical Status classes I and II adult patients were enrolled in the study. After induction and muscle relaxation, mask ventilation was performed with CE and JT technique on PCV mode (Pinsp 15 cm H2O, respiratory rate 15) for 1 min each. The mean of returned TV of last 12 breaths, gastric insufflation, audible mask leak, and operator comfort in each technique were compared. Statistical Analysis: Statistical software namely IBM SPSS 22.0 and R environment version 3.2.2 (IBM Corp. SPSS Statistics for Windows, Version 22.0. Armonk, NY, USA) were used for data analysis. Microsoft Excel was used to generate graphs and tables. Data were expressed as mean ± standard deviation for continuous variables and number (%) for categorical variables. Student's t-test (two tailed, independent) was used to find the significance of the study parameters on a continuous scale. Chi-square/Fisher's exact test was used to find the significance of the study parameters on a categorical scale between two or more groups. Results: There was a significant increase in mean TV generated by JT technique over CE technique (591.46 ± 140.27 mL vs. 544.59 ± 159.08 mL; P < 0.001). Gastric insufflation (12.9% vs. 14.5%) and mask leak (11.3% vs. 38.7%) were more in CE technique. Operator comfort (79% vs. 19.4%) was more in JT technique. Conclusion: A two-handed JT technique is more effective than a one-handed CE technique for mask ventilation in apneic anesthetized adults.

Efficacy of left parapharyngeal pressure combined with cricoid pressure in preventing gastric insufflation during positive pressure ventilation by facemask / 中华麻醉学杂志

Objective:To compare the efficacy of left parapharyngeal pressure (PLP) combined with cricoid pressure in preventing gastric insufflation during positive pressure ventilation by facemask.Methods:Two hundred and forty patients of both sexes, aged 18-75 yr, of American Society of Anesthesiologists physical status Ⅰ or Ⅱ, undergoing surgery under general anesthesia requiring endotracheal intubation, were selected and randomly divided into 4 groups ( n=60 each) using a random number table method: cricoid pressure group (group CP), left PLP group (group LP), cricoid pressure combined with left PLP7 group (group CP+ LP), and control group (group C). The gastric antrum cross-sectional area (CSA) was measured by ultrasound in all the patients before induction of anesthesia, and facemask ventilation in pressure-controlled mode with suction pressure of 25 cmH 2O was applied, the patients in 4 groups were treated with different manipulations, and 3 min later the CSA of gastric antrum was measured again.The gastric antrum CSA before and after ventilation and the difference were recorded.The occurrence of gastric insufflation was examined by ultrasound after ventilation. Results:Compared with the baseline before ventilation, the CSA of gastric antrum was increased after ventilation in C, CP and LP groups ( P<0.01), and no significant change was found in the CSA after ventilation in CP+ LP group ( P>0.05). The difference of gastric antrum CSA was decreased in turn in C, CP, LP and CP+ LP groups ( P<0.05 or 0.01). The incidence of gastric insufflation were 53%, 30%, 12% and 0 in C, CP, LP and CP+ LP groups, respectively.Compared with group C, the incidence of gastric insufflation was significantly decreased in LP and CP+ LP groups ( P<0.05), and no significant change was found in group CP ( P>0.05). Compared with group CP, the incidence of gastric insufflation was significantly decreased in group CP+ LP ( P<0.05), and no significant change was found in group LP ( P>0.05). Conclusion:The combination of left PLP and cricoid pressure can effectively prevent gastric insufflation during positive pressure ventilation by facemask.

[Ultrasound assessment of gastric insufflation in obese patients receiving transnasal humidified rapid-insufflation ventilatory exchange during general anesthesia induction].

OBJECTIVE: To assess the effect of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) on gastric insufflation during general anesthesia induction in obese patients. METHODS: Ninety obese patients (BMI 30-39.9 kg/m2) undergoing laparoscopic cholecystectomy under general anesthesia were randomized into 3 groups (n=30) to receive facemask pre- oxygenation followed by face mask ventilation (FMV) after administration of anesthetics (Group M), oxygenation with THRIVE (Group T), or pre-oxygenation with facemask combined with THRIVE followed continuous oxygenation with both FMV and THRIVE after administration of anesthetics (Group M+T). The patients in the latter two groups received continuous oxygen via THRIVE during tracheal intubation. All the patients received real-time ultrasound monitoring of the gastric antrum, and positive gastric insufflation (GI+) was defined by the presence of comet-tail artifacts. The cross-sectional area of the gastic antrum (CSA-GA) was measured by ultrasound before and after pre-oxygenation and after intubation. The patients' SpO2, PaO2, and PaCO2 at admission (T1), 5 min after pre-oxygenation (T2), 5 min after medication (T3), and immediately after intubation (T4) were recorded, and the incidence of postoperative adverse events was assessed. RESULTS: The incidence of gastric insufflation was significantly higher in Group M and Group M+T than in Group T (P < 0.05). The CSA-GA was significantly greater at T4 than at T1 in Group M and Group M+T and in their GI+s ubgroups. The GI+ subgroups in Group M and Group M+ T had significantly larger CSA-GA at T4 than the GI- subgroups (P < 0.05). CSA-GA did not vary significantly during anesthesia induction in Group T (P>0.05). The incidence of grade Ⅰ gastric distension was lower but grade Ⅱ gastric distention was higher in Group M and Group M+T than in Group T (P < 0.05). Group M showed significantly greater variations of PaO2 at T3 and T4 than Group T and Group M+T (P < 0.05). CONCLUSIONS: Ultrasound monitoring of the comet tail sign and the changes of CSA-GA in the gastric antrum is feasible and reliable for detecting gastrointestinal airflow, and in obese patients, the application of THRIVE for induction of anesthesia can ensure the oxygenation level without further increasing gastric insufflation.

Evaluation of Different Positive End-Expiratory Pressures Using Supreme™ Airway Laryngeal Mask during Minor Surgical Procedures in Children.

Background and objectives: The laryngeal mask is the method of choice for airway management in children during minor surgical procedures. There is a paucity of data regarding optimal management of mechanical ventilation in these patients. The Supreme™ airway laryngeal mask offers the option to insert a gastric tube to empty the stomach contents of air and/or gastric juice. The aim of this investigation was to evaluate the impact of positive end-expiratory positive pressure (PEEP) levels on ventilation parameters and gastric air insufflation during general anesthesia in children using pressure-controlled ventilation with laryngeal mask. Materials and Methods: An observational trial was carried out in 67 children aged between 1 and 11 years. PEEP levels of 0, 3 and 5 mbar were tested for 5 min in each patient during surgery and compared with ventilation parameters (dynamic compliance (mL/cmH2O), etCO2 (mmHg), peak pressure (mbar), tidal volume (mL), respiratory rate (per minute), FiO2 and gastric air (mL)) were measured at each PEEP. Air was aspirated from the stomach at the start of the sequence of measurements and at the end. Results: Significant differences were observed for the ventilation parameters: dynamic compliance (PEEP 5 vs. PEEP 3: p < 0.0001, PEEP 5 vs. PEEP 0: p < 0.0001, PEEP 3 vs. PEEP 0: p < 0.0001), peak pressure (PEEP 5 vs. PEEP 3: p < 0.0001, PEEP 5 vs. PEEP 0: p < 0.0001, PEEP 3 vs. PEEP 0: p < 0.0001) and tidal volume (PEEP 5 vs. PEEP 3: p = 0.0048, PEEP 5 vs. PEEP 0: p < 0.0001, PEEP 3 vs. PEEP 0: p < 0.0001). All parameters increased significantly with higher PEEP, with the exception of etCO2 (significant decrease) and respiratory rate (no significant difference). We also showed different values for air quantity in the comparisons between the different PEEP levels (PEEP 5: 2.8 ± 3.9 mL, PEEP 3: 1.8 ± 3.0 mL; PEEP 0: 1.6 ± 2.3 mL) with significant differences between PEEP 5 and PEEP 3 (p = 0.0269) and PEEP 5 and PEEP 0 (p = 0.0209). Conclusions: Our data suggest that ventilation with a PEEP of 5 mbar might be more lung protective in children using the Supreme™ airway laryngeal mask, although gastric air insufflation increased with higher PEEP. We recommend the use of a laryngeal mask with the option of inserting a gastric tube to evacuate potential gastric air.

Comparison of gastric insufflation using LMA-supreme and I-gel versus tracheal intubation in laparoscopic gynecological surgery by ultrasound: a randomized observational trial.

BACKGROUND: The application of bedside ultrasound to evaluate gastric content and volume can assist in determining aspiration risk. Applying positive pressure ventilation via supraglottic airway devices (SAD) can result in a degree of gastric insufflation. This study assessed and compared the antral cross-sectional area (CSA) in patients undergoing laparoscopic gynecological surgery when managed with different SAD. METHODS: One hundred American Society of Anesthesiologists I or II female patients were assessed for inclusion in this study and divided into three groups of different ventilation devices. Patients were randomly allocated into three groups to receive LMA-Supreme (Group S), I-gel (Group I) or tracheal tube (Group T). The primary outcome was the antral cross-sectional area and secondary outcomes included haemodynamic parameters and postoperative morbidity such as sore throat, hoarseness, dry throat, nausea and vomiting. RESULTS: The antral CSA was not significantly different among three groups before induction (P = 0.451), after induction (P = 0.456) and at the end of surgery (P = 0.195). The haemodynamic variables were significantly higher in the tracheal tube group than in the LMA-Supreme and I-gel groups after insertion (P < 0.0001) and after removal (P < 0.01). Sore throat was detected in none in the I-gel group compare to two patients (6.7%) in the LMA-Supreme group and fifteen patients (50%) in the tracheal tube group. Hoareness was detected in one (3.3%) in the I-gel group compare to two patients (6.7%) in the LMA-Supreme group and eleven patients (36.7%) in the tracheal tube group. CONCLUSIONS: The SADs do not cause obvious gastric insufflation. Thus, LMA-Supreme and I-gel can be widely used as alternative to endotracheal intubation for the short laparoscopic gynecological surgery. TRIAL REGISTRATION: This trial was registered at the Chinese Clinical Trial Registry (ChiCTR1800018212, data of registration, September 2018).

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.

Gastric insufflation during cardiopulmonary resuscitation: A study in human cadavers.

INTRODUCTION: Bag-valve-mask ventilation is the first-line ventilation method during cardiopulmonary resuscitation (CPR). Risks include excessive volume delivery and gastric insufflation, the latter increasing the risk of pneumonia. The efficacy of ventilation can also be reduced by airway closure. We hypothesized that continuous chest compression (CC) could limit the risk of gastric insufflation compared to the recommended 30:2 interrupted CC strategy. This experimental study was performed in human "Thiel" cadavers to assess the respective impact of discontinuous vs. continuous chest compressions on gastric insufflation and ventilation during CPR. METHODS: The 30:2 interrupted CC technique was compared to continuous CC in 5 non-intubated cadavers over a 6 min-period. Flow and Airway Pressure were measured at the mask. A percutaneous gastrostomy allowed measuring the cumulative gastric insufflated volume. Two additional cadavers were equipped with esophageal and gastric catheters instead of the gastrostomy. RESULTS: For the 7 cadavers studied (4 women) median age of death was 79 [74-84] years. After 6 min of CPR, the cumulative gastric insufflation measured in 5 cadavers was markedly reduced during continuous CC compared to the interrupted CC strategy: (1.0 [0.8-4.1] vs. 5.9 [4.0-5.6] L; p < 0.05) while expired minute ventilation was slightly higher during continuous than interrupted CC (1.9 [1.4-2.8] vs. 1.6 [1.1-2.7] L/min; P < 0.05). In 2 additional cadavers, the progressive rise in baseline gastric pressure was lower during continuous CC than interrupted CC (1 and 2 cmH2O vs. 12 and 5.8 cmH2O). CONCLUSION: Continuous CC significantly reduces the volume of gas insufflated in the stomach compared to the recommended 30:2 interrupted CC strategy. Ventilation actually delivered to the lung is also slightly increased by the strategy.

Effect of laryngeal mask and endotracheal tube ventilation on gastric insufflation during general anesthesia with ultrasound evaluation / 上海交通大学学报（医学版）

Objective • To observe the correlation between streamlined liner of pharynx airway (SLIPA) and gastric insufflation. Methods • Seventy patients who underwent elective general anesthesia in Jiading District Central Hospital Affiliated to Shanghai University of Medicine & Health Sciences from September 2017 to May 2018 were included. They were randomly divided into SLIPA group (S group, n=35) and endotracheal tube group (T group, n=35). The gastric antrum ultrasonography was performed at four time points before induction, immediately after intubation (insertion of laryngeal mask), before extubation (laryngeal mask), and immediately after extubation (laryngeal mask), to measure the cross sectional area (CSA) of gastric insufflation. Gastric intake was assessed by ultrasonic measurement of CSA and "comet tail sign" in ultrasound imaging. Pulse oxygen saturation (SpO2), end-tidal pressure of carbon dioxide (PETCO2), peak inspiratory pressure (PIP) and CSA were recorded and compared at the corresponding time points. Results • There was no significant difference in gastric insufflation rate between the two groups during anesthesia (P=0.894). There was no significant difference in SpO2 at each time point between the two groups (all P>0.05). At the end of surgery, PETCO2 in group S was significantly higher than that in group T (P=0.000). Conclusion • Compared with endotracheal tube, the SLIPA does not increase gastric insufflation during general anesthesia.

Ultrasound assessment of gastric insufflation in obese patients receiving transnasal humidified rapid-insufflation ventilatory exchange during general anesthesia induction / 南方医科大学学报

OBJECTIVE@#To assess the effect of transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) on gastric insufflation during general anesthesia induction in obese patients.@*METHODS@#Ninety obese patients (BMI 30-39.9 kg/m@*RESULTS@#The incidence of gastric insufflation was significantly higher in Group M and Group M+T than in Group T (@*CONCLUSIONS@#Ultrasound monitoring of the comet tail sign and the changes of CSA-GA in the gastric antrum is feasible and reliable for detecting gastrointestinal airflow, and in obese patients, the application of THRIVE for induction of anesthesia can ensure the oxygenation level without further increasing gastric insufflation.

Comparison of the changes of antrum and fundus cross‐sectional area measured by bedside ultrasonography on gastric insufflation during general anesthesia in non‐obese women / 中华超声影像学杂志

Objective To compare the changes of antrum and fundus cross‐sectional area ( CSA ) measured by bedside ultrasonography on gastric insufflation during anesthesia induction in non‐obese female patients and analyze the relationships between these changes as well as postoperative nausea and vomiting ( PONV ) . Methods Fourty‐six patients scheduled for elective gynecological laparoscopic operations were enrolled in the study . T he patients w ho appeared the comet‐tail artifacts were defined as gastric insufflation positive group( GI+ group) ,w hile the ones without comet‐tail artifacts were defined as gastric insufflation negative group( GI‐ group) . Blood oxygen saturation ( SPO 2 ) ,end‐expiratory partial pressure of CO 2 ( PET CO2 ) ,tidal volume( T V ) were recorded after 180 seconds ventilation in both groups . T he longitudinal and anteroposterior diameters of gastric antrum and fundus were measured before and after facemask ventilation respectively and the corresponding CSA were calculated . T he cutoff values of prediction of gastric insufflation were determined according to the ROC curve and the corresponding sensitivity and specificity were calculated . PONV of the two groups were also recorded . Results T he analysis was based on the remaining 41 data sets actually . T here were 13 patients in GI‐group and 28 ones in GI+ group . Compared with GI‐group ,the changes of T V and fundus CSA in GI+ group had significantly differences( P ＜0 .05) ; w hile compared with before mask ventilation ,the changes of antrum and fundus CSA in both groups had significantly differences ( P ＜0 .05).T he areas of antrum and fundus CSA under the ROC curve (95% CI) were 0 .67 and 0 .80 ,with cut‐off value 3 .19 cm2 and 24 .90 cm2 ,sensitivity 0 .93 and 0 .93 and specificity 0 .39 and 0 .69 ,respectively .T he incidence of PONV in GI+ group was higher than that in GI‐group( P ＜0 .05). Conclusions Changes of fundus CSA by ultrasonography might be superior to antrum CSA in gastric insufflation caused by 20 cm H2 O peak airway pressure of facemask ventilation during anesthesia induction . Gastric insufflation caused by positive pressure ventilation is related with PONV for young female patients undergoing gynecological laparoscopic operation .

Assessment of effectiveness of cricoid pressure in preventing gastric insufflation during bag and mask ventilation: A randomized controlled trial.

BACKGROUND: Rapid sequence induction and intubation (RSII) with application of "Cricoid pressure" and avoidance of "facemask ventilation" (FMV) is believed to minimize the risk of pulmonary aspiration of gastric contents during general anesthesia. However, some patients may be at risk of developing hypoxemia and may benefit from FMV during RSII. The purpose of this study was to assess the effectiveness of "cricoid pressure" in preventing gastric insufflation during FMV using gastric ultrasonography. MATERIALS AND METHODS: Eighty-four adult patients were randomized to receive cricoid pressure (CP) or no cricoid pressure (NCP), during FMV after induction of general anesthesia. Gastric antral cross-sectional area (CSA) was measured with ultrasonography before and after FMV in supine and right lateral decubitus positions (LDP). Appearance of "comet tail" artifacts created by acoustic shadows of gas in the gastric antrum was noted. RESULTS: The incidence of insufflation indicated by "comet tail" artifacts during FMV was lower in group CP (17 vs 71%; P < 0.001). The lowest P aw at which gastric insufflation occurred was higher in group CP (20 vs 14 cmH2O). The change in mean gastric antral CSA was significantly lower in group CP than in group NCP in supine (0.02 vs 0.36 cm2, P = 0.012) and right LDP (0.03 vs 0.67 cm2, P < 0.001). CONCLUSION: Cricoid pressure is effective in preventing gastric insufflation during FMV at P aw less than 20 cmH2O. Observation of comet tail artifacts in gastric antrum along with measurement of change in antral CSA on ultrasound examination is a feasible and reliable method to detect gastric insufflation.

Ultra-modified rapid sequence induction with transnasal humidified rapid insufflation ventilatory exchange: Challenging convention.

During positive pressure ventilation, gastric inflation and subsequent pulmonary aspiration can occur. Rapid sequence induction (RSI) technique is an age-old formula to prevent this. We adopted a novel approach of RSI for patients with high risk of aspiration and evaluated it further in patients undergoing laparoscopic surgeries. We believe that, in patients with risk of gastric insufflation and pulmonary aspiration, transnasal humidified rapid-insufflation ventilatory exchange can be useful in facilitating pre- and apnoeic oxygenation till tracheal isolation is achieved.

Determination of the optimal inspiratory pressure providing adequate ventilation while minimizing gastric insufflation using real-time ultrasonography in Chinese children: a prospective, randomized, double-blind study.

BACKGROUND: During facemask ventilation, gastric insufflation is defined as appearance of a comet-tail or an acoustic shadow on ultrasonography. Ultrasonographic measurement of antral cross-section area (CSA) may reflect an insufflated antrum and provide interesting semi-quantitative data in regard to the gastric insufflation. This study aimed to determine the appropriate level of inspiratory pressure sufficient to provide adequate pulmonary ventilation with a lower occurrence of gastric insufflation during facemask pressure-controlled ventilation using real-time ultrasonography in paralyzed children. METHODS: Ninety children, ASA I-II, aged from 2 to 4 years, scheduled for general anesthesia were enrolled in this randomized and double-blinded study. Children were randomized into one of the five groups (P8, P10, P12, P14, and P16) defined by the applied inspiratory pressure during facemask ventilation: 8, 10, 12, 14, and 16 cm H2O. Anesthesia induction was conducted with fentanyl and propofol. Rocuronium was administrated as a muscle relaxant. After rocuronium administration, facemask ventilation was performed for 120 s. Gastric insufflation (GI+) was detected by ultrasonography, and the antral CSA before and after facemask ventilation were also measured using ultrasonography. Respiratory variables were monitored. RESULTS: Gastric insufflation was detected in 32 children (3/18 in group P8, 5/18 in group P10, 7/18 in group P12, 8/16 in group P14, and 9/14 in group P16). The antral CSA after facemask ventilation statistically increased in subgroups P14 GI+ and P16 GI+ for whom gastric insufflation was detected by ultrasonography, whereas it did not change statistically in other groups. Lung ventilation was inadequate for group P8 or P10. CONCLUSION: We concluded that an inspiratory pressure of 12 cm H2O is sufficient to provide adequate ventilation with a lower occurrence of gastric insufflation during induction of general anesthesia in paralyzed Chinese children aged from 2 to 4 years old. TRIAL REGISTRATION: ( ChiCTR-IPR-16007960 ). Registered 21 February 2016 Conclusion heading: Ultrasound for determining gastric insufflation.