Tracheal Intubation in Patients at Risk for Cervical Spinal Cord Injury: A Systematic Review

BACKGROUND Tracheal intubation in patients at risk for secondary spinal cord injury is potentially difficult and risky. OBJECTIVES To compare tracheal intubation techniques in adult patients at risk for secondary cervical spinal cord injury undergoing surgery. Primary outcome was first-attempt failure rate. Secondary outcomes were time to successful intubation and procedure complications. DESIGN Systematic review and meta-analysis of randomized controlled trials (RCTs) with trial sequential analysis (TSA). DATA SOURCES Databases searched up to July 2019. ELIGIBILITY Randomized controlled trials comparing different intubation techniques. RESULTS We included 18 trials enrolling 1972 patients. Four studies used the "awake" approach, but no study compared awake versus non-awake techniques. In remaining 14 RCTs, intubation was performed under general anesthesia. First-attempt failure rate was similar when comparing direct laryngoscopy or fiberoptic bronchoscopy versus other techniques. A better first-attempt failure rate was found with videolaryngoscopy and when pooling all the fiberoptic techniques together. All these results appeared not significant at TSA, suggesting inconclusive evidence. Intubating lighted stylet allowed faster intubation. Postoperative neurological complications were 0.34% (no significant difference among techniques). No life-threatening adverse event was reported; mild local complications were common (19.5%). The certainty of evidence was low to very low mainly due to high imprecision and indirectness. CONCLUSIONS Videolaryngoscopy and fiberoptic-assisted techniques might be associated with higher first-attempt failure rate over controls. However, low to very low certainty of evidence does not allow firm conclusions on the best tracheal intubation in patients at risk for cervical spinal cord injury.