How does video laryngoscopy (VL) compare to direct laryngoscopy (DL) in patients with known or predicted difficult airway?

Video Laryngoscopy Should Be Used as First-Line for Patients with Known or Predicted Difficult Airways

According to the most recent evidence, video laryngoscopy (VL) significantly outperforms direct laryngoscopy (DL) in patients with known or predicted difficult airways, with higher first-attempt success rates, improved glottic visualization, and fewer failed intubations. 1

Primary Evidence from Guidelines

The 2022 American Society of Anesthesiologists (ASA) guidelines provide the strongest recommendation based on meta-analyses of randomized controlled trials, demonstrating that VL in patients with predicted difficult airways results in 1:

• Improved laryngeal views (Category A1-B evidence)
• Higher frequency of successful intubations (Category A1-B evidence)
• Higher frequency of first-attempt intubations (Category A1-B evidence)
• Fewer intubation maneuvers required (Category A1-B evidence)

The 2017 Cochrane Review, cited in multiple guidelines, concluded that "statistically significantly fewer failed intubations were reported when a videolaryngoscope was used" and specifically noted "there were fewer failed intubations in those with an anticipated difficult airway when using a videolaryngoscope." 1

Quantitative Performance Data

The most compelling single study demonstrating VL superiority is the 2013 C-MAC randomized controlled trial (n=300 patients with predicted difficult airways), which showed 2:

• First-attempt success: 93% with VL versus 84% with DL (P = 0.026)
• Cormack-Lehane Grade I or II views: 93% with VL versus 81% with DL (P < 0.01)
• Reduced need for adjuncts (bougie/external manipulation): 24% with VL versus 37% with DL (P = 0.020)

A 2015 emergency department study (n=2,423 intubations) demonstrated that as the number of difficult airway characteristics increased, VL maintained superior performance 3:

• No difficult airway characteristics: 90.8% vs 82.0% first-pass success
• One characteristic: 85.1% vs 69.4%
• Two characteristics: 80.5% vs 65.8%
• Three or more characteristics: 68.9% vs 54.1%

Recent Meta-Analysis Confirmation

A 2025 systematic review and meta-analysis of 15 randomized controlled trials (4,582 intubations) in critically ill adults confirmed 4:

• Improved first-attempt success (RR 1.12; 95% CI: 1.04-1.21)
• Reduced esophageal intubation (RR 0.44; 95% CI: 0.26-0.75)
• Reduced dental injuries (RR 0.32; 95% CI: 0.16-0.67)
• Reduced poor glottic visualization

Specific Clinical Scenarios

Cervical Spine Immobilization

The 2024 Difficult Airway Society guidelines provide a Grade A recommendation that "where possible, videolaryngoscopy should be used for tracheal intubation in patients with suspected or confirmed cervical spine injury." 1

Multiple systematic reviews have demonstrated VL superiority in patients with cervical spine immobilization, with increased first-pass success rates particularly when spinal immobilization is maintained. 1

ICU and Emergency Settings

The 2017 French ICU guidelines recommend VL either initially or after failed DL, with preference for first-line use when difficulty is predicted (MACOCHA score ≥3). 1 The McGrath Mac specifically showed superiority in the MACOCHA ≥3 subgroup. 1

A 2012 trauma study (n=709) demonstrated overall VL success of 88% versus 83% with DL (P = 0.05), with multivariate analysis showing DL associated with higher intubation failure risk (OR 1.82,95% CI: 1.15-2.86). 5

Critical Pitfalls and Caveats

When VL May Be Limited

Active upper GI bleeding with blood/secretions: The camera lens can become rapidly obscured, eliminating VL's primary advantage. 6 In patients with bleeding esophageal varices or massive hematemesis, consider awake fiberoptic intubation or DL with immediate suction availability. 6

Technical Considerations

• Intubation time may be longer with VL (averaging 46 seconds vs 33 seconds with DL in one study), which matters in aspiration-risk scenarios. 2
• Risk of airway trauma when using stylets with VL—exercise caution when advancing the endotracheal tube. 7
• Device-specific limitations: mouth opening <2.5 cm, cervical spine fixed in flexion, or proven risk of severe hypoxemia may limit VL use. 6

Operator Expertise

VL performance depends on device type, operator expertise, and patient characteristics—ensure adequate training with the specific device before clinical use. 7 Regular training with cervical spine immobilization is recommended. 1

Practical Algorithm for Device Selection

For patients with known or predicted difficult airway:

1. First-line approach: Use VL (any type—channeled, standard blade, or angulated blade) 1
2. Consider adjuncts: Use stylet or bougie with VL to increase first-pass success, particularly with ≥2 difficult airway characteristics 1
3. Exception: Active massive upper GI bleeding—consider alternative approach (awake technique or DL with aggressive suction) 6
4. Backup plan: Have supraglottic airway device and surgical airway equipment immediately available 7

No specific VL device has proven superiority—the 2024 guidelines state "we are unable to recommend a particular type of videolaryngoscope or a specific type of blade." 1 Use the device with which you have the most training and experience. 1