Manual vs. pressure-controlled facemask ventilation for anaesthetic induction in paralysed children: a randomised controlled trial

Comparison between pressure-controlled and manual ventilation during anesthetic induction in patients with expected difficult airway: A prospective randomized controlled trial

BACKGROUND

Gastric insufflation can cause gastric regurgitation, which may be exacerbated in patients who are expected to have difficult airways. The purpose of this study was to investigate the difference in respiratory parameters and the frequency of gastric insufflation according to the ventilation mode during the anesthestic induction on patients who were predicted to have difficult facemask ventilation.

METHODS

A total of eighty patients with expected airway difficulties were included. Patient were allocated to 2 groups (n = 40 each). In the manual ventilation group, ventilation was performed by putting a mask on the patient's face with 1-hand and adjusting the pressure limiting valve to 15 cm H2O. In the pressure-controlled ventilation group, a mask was held in place using 2-handed jaw-thrust maneuver. The pressure-controlled ventilation was applied and peak inspiration pressure was adjusted to achieve a tidal volume of 6 to 8 mL/kg. The primary outcome was the difference of the peak airway pressure between 2 groups every 30 seconds for 120 seconds duration of mask ventilation. We also evaluated respiratory variables including peak airway pressure, End-tidal carbon dioxide and also gastric insufflation using ultrasonography.

RESULTS

The pressure-controlled ventilation group demonstrated lower peak airway pressure than the manual ventilation group (P = .005). End-tidal carbon dioxide was higher in the pressure-controlled ventilation group (P = .012). The incidence of gastric insufflation assessed by real-time ultrasonography of the gastric antrum was higher in the manual ventilation group than in the pressure-controlled ventilation group [3 (7.5%) vs 17 (42.5%), risk ratio (95% confidence interval): 0.06 to 0.56, P = .003].

CONCLUSIONS

Pressure-controlled ventilation during facemask ventilation in patients who were expected to have difficult airways showed a lower gastric insufflation rate with low peak airway pressure compared to manual ventilation.

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.

Effect of spontaneous breathing on atelectasis during induction of general anaesthesia in infants: A prospective randomised controlled trial

BACKGROUND

Atelectasis occurs commonly during induction of general anaesthesia in children, particularly infants.

OBJECTIVES

We hypothesised that maintaining spontaneous ventilation can reduce atelectasis formation during anaesthetic induction in infants. We compared spontaneous ventilation and manual positive-pressure ventilation in terms of atelectasis formation in infants.

DESIGN

Randomised controlled study.

SETTING

Single tertiary hospital in Seoul, Republic of Korea, from November 2018 to December 2019.

PATIENTS

We enrolled 60 children younger than 1 year of age undergoing general anaesthesia, of whom 56 completed the study. Exclusion criteria were history of hypoxaemia during previous general anaesthesia, development of a respiratory tract infection within 1 month, current intubation or tracheostomy cannulation, need for rapid sequence intubation, preterm birth, age within 60 weeks of the postconceptional age and the presence of contraindications for rocuronium or sodium thiopental.

INTERVENTION

Patients were allocated randomly to either the 'spontaneous' group or 'controlled' group. During preoxygenation, spontaneous ventilation was maintained in the 'spontaneous' group while conventional bag-mask ventilation was provided in the 'controlled' group. After 5 min of preoxygenation, a lung ultrasound examination was performed to compare atelectasis formation in the two groups.

RESULTS

Atelectasis after preoxygenation was seen in seven (26.9%) of 26 patients in the 'spontaneous' group and 22 (73.3%) of 30 patients in the 'controlled' group (P = 0.001). The relative risk of atelectasis in the 'spontaneous' group was 0.39 (95% CI 0.211 to 0.723). Regarding ultrasound pictures of consolidation, the total score and sum of scores in the dependent regions were significantly lower in the 'spontaneous' group than in the 'controlled' group (P = 0.007 and 0.001, respectively).

CONCLUSION

Maintaining spontaneous ventilation during induction of general anaesthesia has a preventive effect against atelectasis in infants younger than 1 year of age, particularly in the dependent portions of the lungs.

TRIAL REGISTRATION

Clinicaltrials.gov (identifier: NCT03739697).

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.

Effect of facemask ventilation with different ventilating volumes on gastric insufflation during anesthesia induction in patients undergoing laparoscopic cholecystectomy

Objectives:

To compare the occurrence of gastric insufflation during anesthesia induction in patients undergoing laparoscopic cholecystectomy, using facemask ventilation with different ventilation volumes.

Methods:

This is a prospective study of 54 patients undergoing laparoscopic cholecystectomy under general anesthesia between January 2018 and June 2018. Facemask ventilation with volume mode controlled at 6 ml/kg (group V6), 8 ml/kg (group V8) or 10 ml/kg (group V10) was applied for 120 seconds (sec) during anesthesia induction. Before facemask ventilation and at 120 sec of facemask ventilation, gastric insufflation was determined by ultrasonography. Gastric insufflation was also evaluated using direct vision of laparoscopy. Respiratory parameters were monitored.

Results:

The incidence of gastric insufflation in group V10 (55.6%) was significantly higher than that in groups V6 (11.1%) and V8 (16.7%). However, it showed no significant difference between groups V6 and V8. During facemask ventilation for 120 sec, carbon dioxide accumulation trend occurred in group V6, and group V10 exhibited evidence of hyper-ventilation. Group V8 might be considered the best balance between low gastric insufflation and effective lung ventilation.

Conclusion:

Facemask ventilation with a ventilation volume of 8 ml/kg seems to have adequate preoxygenation and avoid excessive gastric insufflation during anesthesia induction in laparoscopic cholecystectomy.

Manual vs pressure-controlled facemask ventilation during the induction of general anesthesia in children: A prospective randomized controlled study

BACKGROUND

Gastric insufflation frequently occurs during facemask ventilation in children. In the present study, we compared the incidence of gastric insufflation between pressure-controlled facemask ventilation and manual facemask ventilation during general anesthesia induction in children.

METHODS

Children in the pressure-controlled ventilation group (n = 76) received pressure-controlled facemask ventilation at an inspiratory pressure of 13 cm H₂ O. In the manual ventilation group (n = 75), facemask ventilation was manually performed by anesthesiologists, who tried to maintain an inspiratory pressure of 13 cm H₂ O. The adjustable pressure limiting valve was set at 13 cm H₂ O. The incidence of gastric insufflation during 90 seconds after the initiation of ventilation was assessed using epigastric auscultation and gastric ultrasonography.

RESULTS

The incidence of gastric insufflation was significantly higher in the manual  facemask ventilation group than in the pressure-controlled ventilation group (48% vs 12%, respectively; odds ratio 7.78, 95% confidence interval [CI] 3.38-17.9; P < 0.001). The mean peak airway pressure during ventilation was significantly higher in the manual ventilation group than in the pressure-controlled ventilation group (16.1 [3.0] cm H₂ O vs 13.0 [0.1] cm H₂ O; 95% CI of differences, 2.36-3.71 cm H₂ O; P < 0.001). The manual ventilation group exhibited a wide peak airway pressure  range (11-26 cm H₂ O) and a wide variation of tidal volume (0-7.0 mL/kg) compared with those of the pressure-controlled ventilation group (13-14 cm H₂ O and 0.6-16.0 mL/kg, respectively).

CONCLUSION

At an inspiratory pressure of 13 cm H₂ O, pressure-controlled ventilation may be more effective than manual ventilation in preventing gastric insufflation while providing stable ventilation in children.

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