Abdelmalak 2011.
| Methods | Single‐centre RCT, University hospital, Cleveland, Ohio, USA | |
| Participants | 75 participants > 18 years requiring orotracheal intubation for elective surgery. No details given of type of surgical procedure. BMI > 30 kg /m2 Exclusions: known difficult airway needing awake intubation; loose teeth; pregnant; patient required rapid sequence induction; attending anaesthesiologist required non‐standard TT Median BMI (IQR): FIS 37 (33 to 49); Glidescope 36 (34 to 44) Mean age (SD): FIS 54 years (11); Glidescope 52 years (16) % female: FIS 49%; Glidescope 68% % Caucasian: FIS 97%; Glidescope 87% |
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| Interventions | 37 participants randomly assigned to fibreoptic intubation (FIS). Model of FIS not given. Sniffing position used, with ramp positioned under shoulders. Permitted to use external laryngeal manipulation or to change the position of the participant's head to improve the glottis view or to facilitate intubation 38 participants randomly assigned to videolaryngoscope (VLS). Glidescope: Verathon Medical. Sniffing position used, with ramp positioned under shoulders. Used with Mallinckrodt Satin‐Slip intubating stylet. Permitted to use external laryngeal manipulation or to change the position of the participant's head to improve the glottis view or to facilitate intubation Both groups used Flex‐Tip TT (Parker), size 7.5 for men and 7.0 for women |
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| Outcomes | Failed intubation or change of airway device required. Failed intubation considered as > than three minutes taken or > four attempts Hypoxia < 90% at any time 1 minute before intubation to 10 minutes after Participant‐reported sore throat or hoarseness: rated as mild/ moderate or severe on POD1 Number of attempts for intubation Bleeding on intubation Placement: total time for securing airway device from insertion of Glidescope or for FIS insertion of Williams airway to when end‐tidal PCO2 > 2.7 kPa (given as medians) Difficulty of tracheal intubation, as assessed by intubator on VAS 0 to 100 (given as medians) |
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| Details of anaesthetic induction and intubation | Preoxygenated to end‐tidal O2 conc 80% Standard IV induction. Induction and maintenance of anaesthesia overseen by anaesthesiologist who chose NMBA agent. When paralysed, randomization revealed Used Flex‐Tip TT (Parker), size 7.0 for men and 7.5 for women After induction, ventilated with 100% oxygen until confirmed NMB Mask ventilation permitted between intubation attempts |
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| Training and seniority of intubator | Two “experienced” intubators | |
| Notes | Study supported through internal funding from Cleveland Clinic. Statement indicating no conflicts of interest | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Computer‐generated codes |
| Allocation concealment (selection bias) | Low risk | "Maintained in sequentially numbered opaque envelopes" |
| Blinding of participants and personnel (performance bias) Failed intubation, first success, ease of intubation and time for intubation | High risk | Intubators not blinded |
| Blinding of participants and personnel (performance bias) Hypoxia | Low risk | Standardized preoxygenation protocol. Randomization not revealed until participant paralysed |
| Blinding of participants and personnel (performance bias) Patient‐reported outcomes | Unclear risk | Participants were blinded to allocation. No details of how participants were treated after surgery and pain relief, etc, given. Unclear whether recovery staff were blinded |
| Blinding of outcome assessment (detection bias) Failed intubation, first success, ease of intubation and time for intubation. | High risk | Intubators not blinded |
| Blinding of outcome assessment (detection bias) Hypoxia | Low risk | Observer collecting postintubation records was blinded |
| Blinding of outcome assessment (detection bias) Patient‐reported outcomes | Low risk | Participants were blinded to allocation |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | No apparent losses to follow‐up |
| Selective reporting (reporting bias) | Low risk | All outcomes prespecified in Methods section and on trial register. No outcomes not reported |
| Other bias | Low risk | More men in FIS group. Article gives effect estimates adjusted for age |