Intubation in Surgical Patients: VL vs DL

Background: Although most intubations are typically successful there is still a portion of patients that may require multiple intubation attempts.  Repeated intubation attempts could lead to respiratory and hemodynamic complications. We recently covered the DEVICE trial on REBEL EM which compared a standard geometry video laryngoscopy approach vs a standard geometry direct laryngoscopy approach in critically ill adults requiring intubation.  Video laryngoscopy outperformed direct laryngoscopy in first pass intubation success (85.1% vs 70.8%). We now have a second trial in an operating setting.

Paper: Ruetzler K et al. Video Laryngoscopy vs Direct Laryngoscopy for Endotracheal Intubation in the Operating Room: A Cluster Randomized Clinical Trial. JAMA 2024. PMID: 38497992

Clinical Question: Does video laryngoscopy or direct laryngoscopy decrease the number of intubation attempts in patients undergoing surgical procedures in an operative setting requiring intubation?

What They Did: 

  • Cluster, randomized, multiple crossover clinical trial
  • Conducted at a single US academic hospital
  • Patients enrolled 03/2021 to 12/2022
  • 2 sets of 11 operating rooms were randomized on a 1 week basis to perform hyperangulated video laryngoscopy or direct laryngoscopy for the initial intubation attempt
  • Fluid management, type/dose of anesthetic medications, and postoperative analgesia were at the discretion of the clinician
  • Patients were positioned supine with head elevated and oxygenated with 100% oxygen until the fraction of expired oxygen exceeded 80%
  • Patients intubated approximately 3 minutes after administration of neuromuscular blocking agent


  • Primary: Number of operating room intubation attempts per surgical procedure (Intubation attempt defined by insertion of laryngoscope blade and/or endotracheal tube into a patients mouth)
  • Secondary:
    • Intubation failure (Clinician switching to an alternative laryngoscopy device for any reason at any time OR >3 intubation attempts)
    • Composite of airway and dental injuries


  • Adult patients (≥18 years of age)
  • Having elective or emergent cardiac thoracic, or vascular surgical procedures
  • Required single-lumen endotracheal intubation for general anesthesia


  • Need for double-lumen endotracheal tube
  • Patient already intubated
  • No need for endotracheal intubation
  • COVID-19 diagnosis
  • Staff refusal
  • Educational purposes


  • 8429 surgical procedures in 7736 patients
    • 85% were elective surgical procedures
    • 38.9% of intubations performed by nurse anesthetists
    • 29.8% of intubations performed by residents
    • 14.1% of intubations performed by fellows
    • 13.9% of intubations performed by student nurse anesthetists
  • More Than 1 Intubation Attempt
    • VL: 77/4413 (1.7%)
    • DL:306/4016 (7.6%)
    • OR 0.20; 95% CI 0.14 to 0.28; p <0.001
  • Intubation Failure:
    • VL: 12/4413 (0.27%)
    • DL: 161/4016 (4.0%)
    • RR 0.06; 95% CI 0.03 to 0.14; p< 0.001
  • No significant difference between VL vs DL in airway/dental injuries: 0.93% vs 1.1%


  • Asks a clinically important question
  • An independent committee oversaw the conduct of this trial and adverse events while remaining masked to the primary outcome
  • Used a modified intention-to-treat analysis which includes all patients and better approximates what happens in everyday practice
  • Groups well balanced at baseline


  • Trial stopped early at 2nd interim analysis (50% of expected enrollment) which could overestimate effect size
  • Single center study which may limit generalizability to other institutions
  • Patient positioning was not protocolized
  • Adequate neuromuscular blockade was not standardized
  • Exclusion of several patients could create selection bias
  • Only anesthesia clinicians participated in this study and results could differ with non-anesthesia trained clinicians
  • Number of intubation attempts (primary outcome) is a procedure-oriented outcome not a patient oriented outcome
  • Less than 3% of operators were attending anesthesiologists
  • Intubation attempts is not a patient oriented outcome (i.e. Procedure oriented outcome)


  • Although the authors state that general anesthesia was induced with some combination of the meds below, the exact doses, frequencies, and combinations was not given:
    • Lidocaine 1mg/kg
    • Propofol 1 – 3mg/kg
    • Etomidate 0.2 – 0.3mg/kg
    • Fentanyl 1 – 3ug/kg
    • Succinylcholine 1.5mg/kg
    • Rocuronium 1mg/kg
  • This study did not compare hyperangulated vs standard geometry video laryngoscopy.  However we covered standard vs hyperangulated video laryngoscopy on REBEL Cast episode 87. Both had a similar 1st attempt success rate (91.9% vs 89.2%). The conclusion was clinicians may use whichever blade shape they prefer, with blade shape selection, based on the characteristics of the patient requiring intubation.
  • This study is pragmatic because in an academic center there will be a wide variety of operators.  However, this may not be the case at community centers. Residents, fellows, med students, and SRNAs performed approximately 60% of intubations. As seen in the DEVICE trial, the more experience (repetitions) a clinician has the narrower the gap between the two devices
  • There is very little detailed information on prior operator experience.  There is a big difference in experience between a 1st year resident and 4th year anesthesiology resident. Failure rates per operator type and/or experience level would have been helpful. This extra detail was extremely helpful parsing out the details in the DEVICE trial but that detail is missing in this trial
  • It would have also been helpful to know failure rates in emergent vs elective cases. Though not quite the same as intubating in ED. Emergent cases perhaps less likely to have NPO and full surgical prep

Author Conclusion: “In this study among adults having surgical procedures who required single-lumen endotracheal intubation for general anesthesia hyperangulated video laryngoscopy decreased the number of attempts needed to achieve endotracheal intubation compared with direct laryngoscopy at a single academic medical center in the US.  Results suggest that video laryngoscopy may be a preferable approach for intubating patients undergoing surgical procedures.”

Clinical Take Home Point: In this single center study, in which >60% of intubations were performed by trainees with unclear prior intubation experience, among adult patients having surgical procedures in which a single-lumen endotracheal intubation for general anesthesia was required, a hyperangulated VL approach decreased the number of attempts needed for successful intubation compared to a DL approach.  VL should be our go to initial approach in intubating patients.


  1. Ruetzler K et al. Video Laryngoscopy vs Direct Laryngoscopy for Endotracheal Intubation in the Operating Room: A Cluster Randomized Clinical Trial. JAMA 2024. PMID: 38497992

Post Peer Reviewed By: Marco Propersi, DO (Twitter/X: @marco_propersi)

Cite this article as: Salim Rezaie, "Intubation in Surgical Patients: VL vs DL", REBEL EM blog, April 15, 2024. Available at:

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