Unprotected Airway Research Articles

Outcomes and evaluation of endoscopic retrograde cholangiopancreatography via Gastro-Laryngeal Tube in adult patients: a prospective randomised control study

ABSTRACT Objectives In conventional endoscopic retrograde cholangiopancreatography (ERCP), the patient lies prone or in a semi-prone position under deep sedation and maintains spontaneous ventilation. Sedative-induced respiratory depression and unprotected airway compromise patients’ safety. The gastro-laryngeal tube (G-LT) is a novel reusable supraglottic airway device with two separate ports for endoscopy and ventilation. This study attempts to evaluate the performance characteristic of G-LT. Methods One hundred and forty patients undergoing ERCP were enrolled and randomized. In Group G, patients underwent ERCP with G-LT, whereas Group S patients underwent ERCP conventionally. G-LT insertion attempts, esophageal visualization times, vital parameters, propofol consumption, endoscopists’ and anesthesiologists’ satisfaction scores, time to achieve Modified Aldrete Score of ≥ 9, and complications were recorded. Results Both groups showed similar demographic parameters and 100% procedure completion rates. G-LT group showed shortened esophageal visualization times (4.71 ± 1.687 s vs 7.37 ± 1.515 s) and increased propofol consumption (423.14 ± 106.982 mg vs 178.00 ± 100.125 mg). Group G showed better endoscopic maneuvrability and lesser hemodynamic variability. Sore throat, dysphagia, and mucosal trauma were higher in the G-LT group. Conclusion G-LT provides less intra-procedural hemodynamic changes, quicker esophageal visualization, and better scope maneuvrability at the cost of higher propofol consumption, sore throat, dysphagia, and mucosal trauma. Trial Registration Clinical Trial Registry of India CTRI/2021/06/034212 (Registered on: 14/06/2021)

Intubation for patients with overdose: Time to move on from the Glasgow Coma Scale.

Patients frequently present to the ED with drug overdose and reduced conscious level leading to coma. There is considerable practice variation around which patients require intubation. Indications include: (i) respiratory failure (including airway obstruction); (ii) to facilitate specific therapies or intubation as a therapy in itself; and (iii) for airway protection in the unprotected airway. We argue that intubating a patient purely for (iii) is outdated and that most patients can be safely observed. There is a paucity of good quality research in the area of drug overdose with reduced consciousness. Teaching may be outdated and based on the use of the Glasgow Coma Scale in head trauma. Current low quality research suggests observation is safe. We recommend that patients undergo an individualised risk assessment of the need for intubation. We propose a flow diagram to aid clinicians in safely observing comatose overdose patients. This can be applied if the drug is unknown, or there are multiple drugs involved.

ELEVATIONS IN END TIDAL CO2 WITH CO2 USE DURING PEDIATRIC ENDOSCOPY WITH AIRWAY PROTECTION: IS THIS PHYSIOLOGICALLY SIGNIFICANT?

Inflation of the gastrointestinal lumen is vital for proper visualization during endoscopy. Air, insufflated via the endoscope, is gradually being replaced with carbon dioxide (CO2) in many centers, with the intention of minimizing post-procedural discomfort due to retained gas. Recent studies suggest that the use of CO2 during pediatric esophagogastroduodenoscopy (EGD) with an unprotected airway is associated with transient elevations in exhaled CO2 (end-tidal CO2, EtCO2), raising safety concerns. One possible explanation for these events is eructation of insufflation gas from the stomach. To distinguish eructated vs absorbed CO2 by sampling EtCO2 from a protected airway with either laryngeal mask airway (LMA) or endotracheal tube (ETT), and to observe for changes in minute ventilation (MV) to exclude hypoventilation events. Double-blinded, randomized clinical trial of CO2 versus air insufflation for EGD with airway protection by either LMA or ETT. Tidal volume, respiratory rate, MV, and EtCO2 were automatically recorded every minute. Cohort demographics were described with descriptive characteristics. Variables including the percent of children with peak, transient EtCO2 ≥ 60mmHg were compared between groups. 195 patients were enrolled for 200 procedures. Transient elevations in EtCO2 of ≥ 60mmHg were more common in the CO2 group, compared to the air group (16% vs. 5%, p=0.02), but were mostly observed with LMA and less with ETT. Post-procedure pain was not different between groups, but flatulence was reported more with air insufflation. (p=0.004). Transient elevations in EtCO2 occur more often with CO2 than with air insufflation during pediatric EGD despite protecting the airway with an LMA or, to a lesser degree, with ETT. These elevations were not associated with changes in MV. Although no adverse clinical effects from CO2 absorption were observed, these findings suggest that caution should be exercised when considering the use of CO2 insufflation, especially since the observed benefits of using this gas were minimal.

Oropharyngeal swallowing physiology and safety in patients with Idiopathic Pulmonary Fibrosis: a consecutive descriptive case series

IntroductionDysphagia occurs in multiple respiratory pathophysiologies, increasing the risk of pulmonary complications secondary to aspiration. Reflux associated aspiration and a dysregulated lung microbiome is implicated in Idiopathic Pulmonary Fibrosis (IPF), but swallowing dysfunction has not been described. We aimed to explore oropharyngeal swallowing in IPF patients, without known swallowing dysfunction.MethodsFourteen consecutive outpatients with a secure diagnosis of IPF were recruited and the 10-item Eating Assessment Tool (Eat 10) used to assess patient perception of swallowing difficulty. Oropharyngeal swallowing was assessed in ten patients using Videofluoroscopy Swallow Studies (VFSS). The studies were rated using validated scales: Penetration-Aspiration Scale (PAS); standardised Modified Barium Swallow Impairment Profile (MBSImP).ResultsEAT-10 scores indicated frank swallowing difficulty in 4/14 patients. Videofluoroscopy Studies showed that 3/10 patients had airway penetration, and one aspirated liquid without a cough response. Median MBSImp for oral impairment was 5, range [3–7] and pharyngeal impairment 4, range [1–14] indicating, overall mild alteration to swallowing physiology.ConclusionWe conclude that people with IPF can show a range of swallowing dysfunction, including aspiration into an unprotected airway. To our knowledge, this is the first report on swallowing physiology and safety in IPF. We believe a proportion of this group may be at risk of aspiration. Further work is indicated to fully explore swallowing in this vulnerable group.

High-flow nasal oxygen does not increase the volume of gastric secretions during spontaneous ventilation

BackgroundHigh-flow, heated, and humidified nasal oxygen therapy (HFNO) is frequently used in critical care and perioperative settings for a range of clinical applications. Much of the benefit of HFNO is attributed to generation of modest levels of positive airway pressure. Concern has been raised that this positive airway pressure may cause gastric insufflation, potentially increasing the risk of regurgitation and aspiration in an unprotected airway. MethodsA prospective, interventional, assessor-blinded study was undertaken to evaluate the effects of HFNO on gastric content and gastric distension in healthy fasted adult volunteers assessed by ultrasonography. The primary outcome was the volume of gastric secretions. The secondary outcomes were the incidence of gastric air insufflation and the distribution of gastric antral grades. ResultsSixty subjects were enrolled. No subject was found to have air gastric distension either at baseline or after treatment with HFNO. All subjects had either a Grade 0 or Grade 1 antrum, with similar distribution of antral grades and similar volume of gastric secretions before and after treatment with HFNO. ConclusionsThere was no evidence that treatment with HFNO at flow rates of up to 70 L min−1 for 30 min resulted in gastric distension or an increase in gastric secretions in healthy individuals breathing spontaneously. The generalisability of these findings to subjects under anaesthesia and patients with incompetence of the lower oesophageal sphincter or impaired gastric emptying requires further investigation. Clinical trial registrationNCT03134937.

Lavage or not to lavage – hazards due to deviation from National Guidelines

Self-poisoning with organophosphorus (OP) compounds has contributed to a large number of deaths in the developing world over many decades. While, most deaths are due to the inherent properties of the OP compounds, an important sub group of patients die due to iatrogenic causes, prevention of which will reduce death rates. In most developing countries, there is no continuous medical education of doctors who deliver primary care in rural villages which lead to iatrogenic deaths and disability. We present two patients who presented unconscious to primary care units following ingestion of OP compounds. Both patients received gastric lavage by medically unqualified personnel, with unprotected airways and without informed consent. Both patients were transferred to a specialized unit with an unprotected airway and both aspirated gastric contents which lead to mechanical ventilation and prolonged hospital stay. In both cases, the medical management deviated from accepted good clinical practice and National Guidelines. Reducing deaths from pesticide self-poisoning would require a coordinated effort involving new antidote development and optimizing medical care given to these patients at both primary and tertiary care units. Minimizing iatrogenic causes of morbidity and mortality would require a National approach at undergraduate and postgraduate levels. New mechanisms to improve knowledge of resuscitation, airway management and adherence to good clinical practice by primary care doctors should be initiated.

Fast or Slow Rescue Ventilations: A Predictive Model of Gastric Inflation.

Rescue ventilations are given during respiratory and cardiac arrest. Tidal volume must assure oxygen delivery; however, excessive pressure applied to an unprotected airway can cause gastric inflation, regurgitation, and pulmonary aspiration. The optimal technique provides mouth pressure and breath duration that minimize gastric inflation. It remains unclear if breath delivery should be fast or slow, and how inflation time affects the division of gas flow between the lungs and esophagus. A physiological model was used to predict and compare rates of gastric inflation and to determine ideal ventilation duration. Gas flow equations were based on standard pulmonary physiology. Gastric inflation was assumed to occur whenever mouth pressure exceeded lower esophageal sphincter pressure. Mouth pressure profiles that approximated mouth-to-mouth ventilation and bag-valve-mask ventilation were investigated. Target tidal volumes were set to 0.6 and 1.0 L. Compliance and airway resistance were varied. Rapid breaths shorter than 1 s required high mouth pressures, up to 25 cm H2O to achieve the target lung volume, which thus promotes gastric inflation. Slow breaths longer than 1 s permitted lower mouth pressures but increased time over which airway pressure exceeded lower esophageal sphincter pressure. The gastric volume increased with breath durations that exceeded 1 s for both mouth pressure profiles. Breath duration of ∼1.0 s caused the least gastric inflation in most scenarios. Very low esophageal sphincter pressure favored a shift toward 0.5 s. High resistance and low compliance each increased gastric inflation and altered ideal breath times. The model illustrated a general theory of optimal rescue ventilation. Breath duration with an unprotected airway should be 1 s to minimize gastric inflation. Short pressure-driven and long duration-driven gastric inflation regimens provide a unifying explanation for results in past studies.

Emergency Airway Management in Neck Trauma

Airway management in patients who have sustained direct trauma to the airway is among the most challenging problems for emergency clinicians. Blunt or penetrating injuries to the head, oropharynx, neck, or upper chest can result in immediate or delayed airway obstruction. Immediate, definitive airway management is needed when the patient cannot protect his airway or is unable to sufficiently oxygenate or ventilate. Emergent or urgent airway management is specified when a patient develops respiratory distress or when symptoms are progressing rapidly. In addition, airway management often is indicated when the patient appears clinically stable, but the clinician anticipates clinical decline (e.g., smoke inhalation, edema, subcutaneous air, hematoma) or feels that an unprotected airway presents a risk to the patient who requires transport to another facility or to radiology for extensive diagnostic studies. The higher rate of complicated airways in this population mandates that the clinician has to be prepared to use advanced airway techniques, including a surgical airway.

The risk factors of intraoperative anesthesia adverse events in children with laryngeal diseases

BackgroundThis study aimed to investigate the risk factors of intraoperative anesthesia adverse events (IAAEs) in children with laryngeal diseases. MethodsWe retrospectively recruited 118 children with laryngeal diseases who underwent surgical therapy. Based on medical history and preoperative imaging diagnosis, the baseline data, including sex, age, weight, onset age, the number of operation, the degree of airway obstruction, the nature of disease, the location of disease, complications, tracheotomy, and trachea intubation, were defined and recorded. IAAEs, such as pulse oxygen saturation (SpO2) decline, heart rate (HR) decline, emergency orotracheal intubation, emergency tracheotomy, and remaining intubated postoperatively, were also recorded. The risk factors for IAAEs were identified using multivariate logistic regression model. ResultsIncreasing severity of airway obstruction and the presence of pneumonia were risk factors for SpO2 and HR decline in children with laryngeal diseases. Older age, supraglottic rather than subglottic disease, and trachea intubation rather than unprotected airway during surgery were protective factors for SpO2 decline. Furthermore, severe airway obstruction increased risks of emergency orotracheal intubation and remaining intubated postoperatively, whereas supraglottic rather than subglottic disease were protective factors for emergency orotracheal intubation and remaining intubated postoperatively. Only HR decline was found to be associated with the presence of congenital heart disease. ConclusionsThe severe airway obstruction increases the risk of SpO2 decline and HR decline as well as the possibility of perioperative emergency orotracheal intubation and remaining intubated postoperatively, whereas supraglottic surgery and surgery performed under endotracheal intubation reduce the incidence rates of these IAAEs in children with laryngeal diseases.

Effects of Stomach Inflation on Cardiopulmonary Function and Survival During Hemorrhagic Shock: A Randomized, Controlled, Porcine Study.

Ventilation of an unprotected airway may result in stomach inflation. The purpose of this study was to evaluate the effect of clinically realistic stomach inflation on cardiopulmonary function during hemorrhagic shock in a porcine model. Pigs were randomized to a sham control group (n = 9), hemorrhagic shock (35 mL kg over 15 min [n = 9]), and hemorrhagic shock combined with stomach inflation (35 mL kg over 15 min and 5 L stomach inflation [n = 10]). When compared with the control group, hemorrhagic shock (n = 9) increased heart rate (103 ± 11 vs. 146 ± 37 beats min; P = 0.002) and lactate (1.4 ± 0.5 vs. 4.0 ± 1.9 mmol L; P < 0.001), and decreased mean arterial blood pressure (81.3 ± 12.8 vs. 35.4 ± 8.1 mmHg; P < 0.001) and stroke-volume index (38.1 ± 6.4 vs. 13.6 ± 4.8 mL min m; P < 0.001). Hemorrhagic shock combined with stomach inflation (n = 10) versus hemorrhagic shock only (n = 9) increased intra-abdominal pressure (27.0 ± 9.3 vs. 1.1 ± 1.0 mmHg; P < 0.001), and decreased stroke-volume index (9.9 ± 6.0 vs. 20.8 ± 8.5 mL min m; P = 0.007), and dynamic respiratory system compliance (10.8 ± 4.5 vs. 38.1 ± 6.1 mL cmH2O; P < 0.001). Before versus after stomach evacuation during hemorrhagic shock, intra-abdominal pressure decreased (27.0 ± 9.3 vs. 9.8 ± 5.4 mmHg; P = 0.042). Survival in the sham control and hemorrhagic shock group was 9 of 9, respectively, and 3 of 10 after hemorrhagic shock and stomach inflation (P < 0.001). During hemorrhagic shock stomach inflation caused an abdominal compartment syndrome and thereby impaired cardiopulmonary function and aerobic metabolism, and increased mortality. Subsequent stomach evacuation partly reversed adverse stomach-inflation triggered effects.

A multi-institutional pilot survey of anesthesia practices during proton radiation therapy

Background and purposePhysicians responsible for anesthesia and/or sedation (A/S) at emerging proton radiation therapy centers (PTCs) seek information about practices at established centers. We conducted a survey of A/S practices at established PTCs to provide this information for physicians at new PTCs. Methods and materialsA web-based survey was sent to physicians responsible for A/S at 37 established PTCs. Questions were based on practice patterns and the preferred method of A/S delivery during proton-radiation therapy. One representative per institution was surveyed. ResultsA response rate of 38%, with a combined case load of more than 15,000 anesthetics per year was obtained. Children younger than 4 years old often (72%) required A/S. The most favored A/S techniques involved total intravenous anesthesia with propofol and an unprotected airway (57%) or general anesthesia with sevoflurane and a laryngeal mask airway (36%). It was notable that 21% of facilities did not have dedicated recovery rooms. Also, anesthesia gas evacuation outlets were absent at 43% of treatment rooms. ConclusionsA/S is commonly delivered to patients undergoing proton radiation therapy, most often with total intravenous anesthesia. To avert potential obstacles to the safe delivery of care, anesthesiologists at emerging centers are encouraged to participate throughout the design and planning phases of new PTCs.

Generation of tidal volume via gentle chest pressure in children over one year old

BackgroundIn the event of cardiac arrest, cardiopulmonary resuscitation (CPR) is a well-established technique to maintain oxygenation of tissues and organs until medical equipment and staff are available. During CPR, chest compressions help circulate blood and have been shown in animal models to be a means of short-term oxygenation. In this study, we tested whether gentle chest pressure can generate meaningful tidal volume in paediatric subjects. MethodsThis prospective cohort pilot study recruited children under the age of 17 years and undergoing any surgery requiring general anaesthetic and endotracheal intubation. After induction of general anaesthesia, tidal volumes were obtained before and after intubation by applying a downward force on the chest which was not greater than the patient's weight. Mean tidal volumes were compared for unprotected versus protected airway and for type of surgery. ResultsMean tidal volume generated with an unprotected and protected airway was 2.7 (1.7) and 2.9 (2.3)mL/kg, respectively. Mean tidal volume generated with mechanical ventilation was 13.6 (4.9)mL/kg. No statistical significance was found when comparing tidal volumes generated with an unprotected or protected airway (p=0.20), type of surgery (tonsillectomy and/or adenoidectomy versus other surgery) (unprotected, p=0.09; protected, p=0.37), and when age difference between groups was taken into account (p=0.34). ConclusionsUsing gentle chest pressure, we were able to generate over 20% of the tidal volume achieved with mechanical ventilation. Our results suggest that gentle chest pressure may be a means to support temporary airflow in children.

Back To Blockers?

Back To Blockers?

Reduction of gastric inflation by use of a pressure relief valve connected to an acoustic expiration control device during mouth-to-mask ventilation of a manikin model of an unprotected airway

BackgroundGastric inflation is a significant issue when ventilation of the unprotected airway is performed. The purpose of this study was to evaluate a prototype pressure relief valve with an acoustic...

Flexible fiber CO2 laser ablation of subglottic and tracheal stenosis

Flexible fiber CO2 laser ablation of subglottic and tracheal stenosis

Allocating Scarce Resources in Disasters: Emergency Department Principles

Decisions about medical resource triage during disasters require a planned structured approach, with foundational elements of goals, ethical principles, concepts of operations for reactive and proactive triage, and decision tools understood by the physicians and staff before an incident. Though emergency physicians are often on the front lines of disaster situations, too often they have not considered how they should modify their decisionmaking or use of resources to allow the "greatest good for the greatest number" to be accomplished. This article reviews key concepts from the disaster literature, providing the emergency physician with a framework of ethical and operational principles on which medical interventions provided may be adjusted according to demand and the resources available. Incidents may require a range of responses from an institution and providers, from conventional (maximal use of usual space, staff, and supplies) to contingency (use of other patient care areas and resources to provide functionally equivalent care) and crisis (adjusting care provided to the resources available when usual care cannot be provided). This continuum is defined and may be helpful when determining the scope of response and assistance necessary in an incident. A range of strategies is reviewed that can be implemented when there is a resource shortfall. The resource and staff requirements of specific incident types (trauma, burn incidents) are briefly considered, providing additional preparedness and decisionmaking tactics to the emergency provider. It is difficult to think about delivering medical care under austere conditions. Preparation and understanding of the decisions required and the objectives, strategies, and tactics available can result in better-informed decisions during an event. In turn, adherence to such a response framework can yield thoughtful stewardship of resources and improved outcomes for a larger number of patients.

Tracheotomy in the Unprotected Airway

Although rare, there are many circumstances in which a secure airway is needed urgently. A newly developed technique is presented for quick and efficient performance of this procedure. All patients who had tracheotomies performed at a tertiary referral center from January 1, 2004, through December 31, 2008, were found by querying the admission database. Three hundred twenty-seven separate procedures performed in 325 patients were identified. Urgent tracheotomies were distinguished from elective and emergent tracheotomies by reading operative reports and excluding elective and emergent procedures. Elective procedures were defined as performed in patients with a secure airway (with an endotracheal tube or laryngeal mask airway). Urgent tracheotomies were defined as having an intact, unprotected airway. Emergent procedures were performed in a patient with complete airway obstruction. Twenty instances of urgent, awake tracheotomies were found in 19 patients, resulting in an incidence of 20 of 327 tracheotomies (6.1%) in 19 of 325 patients (5.8%). Tracheotomy is an alternative to cricothyroidotomy as a surgical airway in patients with deteriorating respiratory status who cannot be safely intubated by nonsurgical means.

Head-position angles in children for opening the upper airway

Aims Inexperienced health-care-providers may encounter severe problems to ventilate an unconscious child. Designing a ventilating device that could indicate how to open an upper airway correctly may be beneficial. Neutral position in young children and slight head extension in older children is recommended, although the optimal head angle is not clear. Thus, we compared effects of neutral head position and extension, measuring head-position angles and ventilation parameters. Methods Sixty-one children scheduled for tonsillectomy were enrolled, and were ventilated with pressure-controlled ventilation after anaesthesia induction. Results Children were divided into two groups: 1–5 years old (pre-school children, n = 38) and 6–10 years old (school children, n = 23). In neutral (mean ± SD: 1.3 ± 6.0) vs. head-extension position (13.2 ± 6.0; P < 0.001) in pre-school children, tidal volumes (132 ± 44,137 ± 49 ml), peak-expiratory flow (300 ± 90 vs. 310 ± 100 ml s −1) and expiratory airway resistance (20 ± 8 vs. 18 ± 6 cmH 2O s l −1) were comparable ( P = NS). In neutral (−0.4 ± 5.4) vs. head-extension position (15.7 ± 6.4; P < 0.001) in school children, expiratory airway resistance (17 ± 7 vs. 13 ± 5 cmH 2O s l −1; P = 0.048) differed, while tidal volume (224 ± 93 vs. 230 ± 92 ml) and peak-expiratory flow (427 ± 181 vs. 381 ± 144 ml s −1) were comparable ( P = NS). Conclusions Head-extension and neutral head-position angles differed in pre-school and school children. In pre-school children, neutral head position or head extension with an angle of −1° or 13°, and in school children head extension of 16°, may be used to achieve optimal ventilation of an unprotected airway.

A comparative study of conventional general anaesthesia with total intravenous anaesthesia (TIVA) in cervical cerclage - Prospective randomized study

Background: Cervical cerclage, is performed either under regional or general anaesthetic techniques. General anaesthesia with endotracheal intubation is popular to protect air way from acid aspiration. Total intravenous anaesthesia (TIVA) technique is often not practiced, with the fear of unprotected airway and possible effect of drugs on foetus. This study was designed to verify the safety of TIVA in cervical cerclage. Patients & Methods : In a prospective randomized study, 60 ASA I st atus patients, undergoing cervical cerclage (14-16 gestation week) for cervical incompetence were grouped into 30 each. Group A received TIVA ( 2mcg kg -1 fentanyl with propofol for induction and maintenance) with spontaneous breathing using Hudson mask for oxygenation. Group B received general anesthesia with intubation and controlled ventilation. Both groups received tablets ranitidine 150mg and metaclopropramide 10mg one hour before surgery. In the recovery room were monitored for wakefulness, orientation, nausea, vomiting, and pain (verbal rating scale). They were followed at delivery for congenital anomalies and Apgar score. Results : At the end of the procedure 90 percent (27/30) in Group A were awake and oriented. In Group B 30 percent (9/ 30) were awake and 13.33 percent (4/30) oriented with statistical significance (X2 test) at < 0.001 p. None in Group A had nausea, vomiting or pain in the recovery room. In Group B 16.66 percent (5/30) complained of nausea and pain while 50 percent (15/30) had only pain requiring treatment with statistical significance at < 0.05 and < 0.001 p respectively . The mean duration of surgery in Group A was 32.28 (SE1.78) and in Group B 42.17(SE1.87) minutes with 95% confidence limit. Both groups had no congenit al anomalies with Apgar scores 9 at one and 10 at five minutes. The age and weight were not clinically and statistically significant. Conclusion : TIVA using Fentanyl and propofol for cervical cerclage until 16weeks of pregnancy is safe with no adverse effects on the mother and the foetus. It provides early recovery with no pain and Post operative nausea and vomiting

Comparison of three modes of positive pressure mask ventilation during induction of anaesthesia: a prospective, randomized, crossover study

Mask ventilation of apnoeic patients may be associated with alveolar hypoventilation, hyperventilation and gastric insufflation, which may be affected by the mode of ventilation during induction of anaesthesia. This study is to compare the effect of three modes of positive pressure mask ventilation during induction of anaesthesia regarding ventilatory variables and gastric insufflation. Ninety (90) patients, ASA I-II were included in this prospective, randomized, crossover study. Patients were divided into three groups of different sequence of modes of ventilation. Each patient was ventilated with pressure-controlled ventilation (PCV), manual-controlled ventilation (MCV), and volume-controlled ventilation (VCV) during the induction of anaesthesia. Respiratory and haemodynamic variables were monitored. Gastric insufflation was detected with a stethoscope applied to epigastric area. Haemodynamic variables showed no significant differences between the three modes of ventilation. PCV was associated with lower peak airway pressures (11.4 +/- 1.2 cmH2O) compared with MCV and VCV (14.3 +/- 1.7 and 13.3 +/- 1.5 cmH2O; respectively P < 0.0001). Inspiratory and expiratory tidal volumes showed no significant differences between the three modes. Gastric insufflation was detected in one patient (1.1%) in the PCV group compared to three patients (3.3%) in the MCV group and three patients (3.3%) in the VCV group. We concluded that in this model of apnoeic patients with an unprotected airway, PCV was associated with lower peak airway pressure which may provide additional patient safety.