TY - JOUR
T1 - Impaired upper airway integrity by residual neuromuscular blockade
T2 - Increased airway collapsibility and blunted genioglossus muscle activity in response to negative pharyngeal pressure
AU - Herbstreit, Frank
AU - Peters, Jürgen
AU - Eikermann, Matthias
PY - 2009/6
Y1 - 2009/6
N2 - Background: Residual neuromuscular blockade increases the risk to develop postoperative complications. The authors hypothesized that minimal neuromuscular blockade (train-of-four [TOF] ratio 0.5-1) increases upper airway collapsibility and impairs upper airway dilator muscle compensatory responses to negative pharyngeal pressure challenges. Methods: Epiglottic and nasal mask pressures, genioglossus electromyogram, respiratory timing, and changes in lung volume were measured in awake healthy volunteers (n = 15) before, during (TOF = 0.5 and 0.8 [steady state]), and after recovery of TOF to unity from rocuronium-induced partial neuromuscular blockade. Passive upper airway closing pressure (negative pressure drops, random order, range +2 to -30 cm H2O) and pressure threshold for flow limitation were determined. RESULTS: Upper airway closing pressure increased (was less negative) significantly from baseline by 54 ± 4.4% (means ± SEM), 37 ± 4.2%, and 16 ± 4.1% at TOF ratios of 0.5, 0.8, and 1.0, respectively (P < 0.01 vs. baseline for any level). Phasic genioglossus activity almost quadrupled in response to negative (-20 cm H2O) pharyngeal pressure at baseline, and this increase was significantly impaired by 57 ± 44% and 32 ± 6% at TOF ratios of 0.5 and 0.8, respectively (P < 0.01 vs. baseline). End-expiratory lung volume, respiratory rate, and tidal volume did not change. Conclusion: Minimal neuromuscular blockade markedly increases upper airway closing pressure, partly by impairing the genioglossus muscle compensatory response. Increased airway collapsibility despite unaffected values for resting ventilation may predispose patients to postoperative respiratory complications, particularly during airway challenges.
AB - Background: Residual neuromuscular blockade increases the risk to develop postoperative complications. The authors hypothesized that minimal neuromuscular blockade (train-of-four [TOF] ratio 0.5-1) increases upper airway collapsibility and impairs upper airway dilator muscle compensatory responses to negative pharyngeal pressure challenges. Methods: Epiglottic and nasal mask pressures, genioglossus electromyogram, respiratory timing, and changes in lung volume were measured in awake healthy volunteers (n = 15) before, during (TOF = 0.5 and 0.8 [steady state]), and after recovery of TOF to unity from rocuronium-induced partial neuromuscular blockade. Passive upper airway closing pressure (negative pressure drops, random order, range +2 to -30 cm H2O) and pressure threshold for flow limitation were determined. RESULTS: Upper airway closing pressure increased (was less negative) significantly from baseline by 54 ± 4.4% (means ± SEM), 37 ± 4.2%, and 16 ± 4.1% at TOF ratios of 0.5, 0.8, and 1.0, respectively (P < 0.01 vs. baseline for any level). Phasic genioglossus activity almost quadrupled in response to negative (-20 cm H2O) pharyngeal pressure at baseline, and this increase was significantly impaired by 57 ± 44% and 32 ± 6% at TOF ratios of 0.5 and 0.8, respectively (P < 0.01 vs. baseline). End-expiratory lung volume, respiratory rate, and tidal volume did not change. Conclusion: Minimal neuromuscular blockade markedly increases upper airway closing pressure, partly by impairing the genioglossus muscle compensatory response. Increased airway collapsibility despite unaffected values for resting ventilation may predispose patients to postoperative respiratory complications, particularly during airway challenges.
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U2 - 10.1097/ALN.0b013e31819faa71
DO - 10.1097/ALN.0b013e31819faa71
M3 - Article
C2 - 19417617
AN - SCOPUS:67049146252
VL - 110
SP - 1253
EP - 1260
JO - Anesthesiology
JF - Anesthesiology
SN - 0003-3022
IS - 6
ER -