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Left paratracheal pressure during anaesthesia induction

Year: 2026
Type: article
Abstract: Editor, Cricoid pressure remains widely used during rapid sequence induction despite ongoing debate regarding effectiveness and potential airway impairment.1,2 Left paratracheal pressure (LPP) has been proposed to compress the oesophageal lumen while minimising laryngeal distortion.3,4 Before definitive head-to-head trials against cricoid pressure, it is important to confirm that LPP does not worsen routine laryngoscopy or intubation conditions.5 We therefore conducted an exploratory randomised trial comparing LPP with no external pressure during standardised elective induction. Ethics and registration: Ethical approval for this study was provided by the Ethics Committee of the University of Liège Hospital (31 March 2021; ref. 2020/85, chairperson Professor Vincent Seutin). Written informed consent was obtained from all participants and procedures complied with the Declaration of Helsinki. The trial was registered before enrolment (ClinicalTrials.gov NCT04173910). Design and participants: Single-centre, single-blind, exploratory randomised controlled trial conducted from May to October 2021 in elective adult surgical patients requiring orotracheal intubation. Key exclusions were pregnancy, age younger than 18 years, and significant neck/upper-airway pathology. Randomisation and blinding: Participants were randomised 1 : 1 using sealed opaque envelopes. The intubating anaesthesiologist was blinded; LPP was applied by a separate trained operator behind an opaque drape. Anaesthesia and airway protocol: Induction used sufentanil 0.1 μg·kg−1, propofol 2 mg kg−1, lidocaine 1 mg kg−1, and rocuronium 0.6 mg kg−1, followed by mask ventilation for 2 to 3 minutes. Direct laryngoscopy (Macintosh size-3 blade) in the sniffing position was standardised to reduce measurement variability. Intervention: In the LPP group, the operator applied LPP behind an opaque drape at a predefined left paratracheal landmark (illustrated in Fig. 1) aiming for ~30 N based on prior dynamometer training. Training consisted of a brief force calibration session using a handheld dynamometer; operators practised until they could reproduce 30 N (+/−5 N) over at least three consecutive attempts before participating in the trial. LPP was applied from loss of consciousness and maintained during mask ventilation and laryngoscopy until cuff inflation, unless the intubator requested release. Sham manoeuvre (no pressure) performed behind the same drape.Fig. 1: Blinded application of left paratracheal pressure during anaesthesia induction.Management of CL III/IV or difficulty: If CL III/IV view or difficult tube passage occurred, usual optimisation (positioning and/or external laryngeal manipulation) was permitted. In the LPP group, LPP was immediately released upon request. If difficulty persisted, rescue followed the local difficult airway algorithm including videolaryngoscopy and/or a second anaesthesiologist (recorded within the Likert scale as maximal difficulty). Rescue planning was aligned with the Difficult Airway Society guideline for unanticipated difficult intubation in adults.6 Outcomes: co-primary outcomes were modified CL grade and intubation ease (4-point Likert). Secondary outcomes included intubation time (laryngoscope insertion to cuff inflation), desaturation (SpO2 < 94%), ventilation required between attempts, difficult intubation, and LPP release. As an exploratory study, no formal sample-size calculation was performed; effect estimates are presented with 95% confidence intervals. Ninety-eight patients were analysed (LPP n = 48; sham n = 50). Modified CL grade distributions were similar: CL I–II occurred in 44/48 with LPP and 46/50 with sham. Ease score 1 to 2 occurred in 45/48 and 48/50, respectively. Mean intubation time was 27.7 (27.1) s with LPP versus 33.2 (45.2) s with sham (mean difference −5.5 s; 95% CI −20.2 to 9.2). LPP release was requested in 3/48; ventilation between attempts occurred in 4/48 and 2/50. No regurgitation or aspiration events were observed. Full baseline and outcome tables and the CONSORT flow diagram are provided as Supplemental Digital Content (Table, SDC 1, https://links.lww.com/EJAIC/A173 and 2, https://links.lww.com/EJAIC/A174; Fig. 2).Fig. 2: CONSORT flow diagram of patient enrolment, randomisation, allocation, follow-up, and analysis.In this exploratory, blinded-assessment trial, applying LPP during standardised elective induction did not worsen laryngoscopic view or intubation conditions compared with no external pressure. However, LPP release was occasionally requested, highlighting that the manoeuvre should remain readily reversible. This study was not designed to assess prevention of aspiration and did not include a cricoid pressure comparator; accordingly, our findings should be interpreted as hypothesis-generating and supportive of airway ‘neutrality’ rather than definitive clinical effectiveness. Additional limitations include the single-centre setting, the 2021 study period, and the use of direct laryngoscopy rather than routine videolaryngoscopy, which may limit generalisability to contemporary practice. Based on the low incidence of poor laryngoscopic view observed here (~8%), a definitive two-group trial designed to detect a 10% absolute difference in this outcome would require approximately 170 participants per arm (before accounting for attrition); aspiration-related endpoints would require substantially larger samples .4–7 LPP applied during standardised elective induction did not appear to impair laryngoscopic view or intubation conditions versus no pressure, although occasional release was required. As this exploratory study was not powered to detect small differences, these findings should be interpreted as hypothesis-generating and primarily inform the design of an adequately powered head-to-head trial versus cricoid pressure.
Language: English
Field: Medicine
Open Access status: diamond
OpenAlex ID: W7163185106
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Cites: 7
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