Anesthesia Techniques and Monitors

The effect of neuromuscular blockade on mask ventilation

Warters RD, Szabo TA, Spinale FG, et al (Med Univ of South Carolina, Charleston) Anaesthesia 66:163-167, 2011^§

Abstract

We wished to test the hypothesis that neuromuscular blockade facilitates mask ventilation. In order reliably and reproducibly to assess the efficiency of mask ventilation, we developed a novel grading scale (Warters scale), based on attempts to generate a standardised tidal volume. Following induction of general anaesthesia, a blinded anaesthesia provider assessed mask ventilation in 90 patients using our novel grading scale. The non-blinded anaesthesiologist then randomly administered rocuronium or normal saline. After 2 min, mask ventilation was reassessed by the blinded practitioner. Rocuronium significantly improved ventilation scores on the Warters scale (mean (SD) 2.3 (1.6) vs 1.2 (0.9), p < 0.001). In a subgroup of patients with a baseline Warters scale value of > 3 (i.e. difficult to mask ventilate; n = 14), the ventilation scores also showed significant improvement (4.2 (1.2) vs 1.9 (1.0), p = 0.0002). Saline administration had no effect on ventilation scores. Our data indicate that neuromuscular blockade facilitates mask ventilation. We discuss the implications of this finding for unexpected difficult airway management and for the practice of confirming adequate mask ventilation before the administration of neuromuscular blockade (Fig 1).

Figure 1 Histograms presenting raw data and estimated distribution of ventilation scores for the Han scale at baseline and 2 min after saline (a, b) or rocuronium (c, d) administration. (Reprinted from Warters RD, Szabo TA, Spinale FG, et al. The effect of neuromuscular blockade on mask ventilation. Anaesthesia. 2011;66:163-167, with permission from The Association of Anaesthetists of Great Britain and Ireland.)

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

of change in daily step count over five years with insulin sensitivity and adiposity: population based cohort study of Cancer: The Next Generation Beverages and Risk of Metabolic Syndrome and Type 2 Diabetes: A meta-analysis time and haemodynamic response after thiopental vs. propofol in the elderly: a randomized trial monitoring of neuromuscular block over the orbicularis oris muscle in anesthetized patients receiving vecuronium Is Better Than General Anesthesia During Endovascular Acute Stroke Interventions