TY - JOUR
T1 - Intrinsic positive end-expiratory pressure during ventilation through small endotracheal tubes during general anesthesia
T2 - Incidence, mechanism, and predictive factors
AU - Gemma, Marco
AU - Nicelli, Elisa
AU - Corti, Daniele
AU - De Vitis, Assunta
AU - Patroniti, Nicolò
AU - Foti, Giuseppe
AU - Calvi, Maria Rosa
AU - Beretta, Luigi
PY - 2016/6/1
Y1 - 2016/6/1
N2 - Study Objective To assess the safety of mechanical ventilation and effectiveness of extrinsic positive end-expiratory pressure (PEEP) (PEEPe) in improving peripheral oxygen saturation (SpO2) during direct microlaryngeal laser surgery; to assess the incidence, amount, and nature (dynamic hyperinflation or airflow obstruction) of ensuing intrinsic PEEP (PEEPi); and to find a surrogate PEEPi indicator. Design Quasiexperimental. Setting S. Raffaele Hospital (Milano), November 2009 to December 2010. Patients Fifty-two adults scheduled for direct microlaryngeal laser surgery. Exclusion criterion is pregnancy. Interventions Twenty-one percent O2 mechanical ventilation through 4.5- to 5.5-mm internal diameter endotracheal tubes; in 29 patients, after measurement of PEEPi, an identical amount of PEEPe was added; and PEEPi. Measurements SpO2, peak (Pawpeak) and plateau (Pawplateau) airway pressure, and end-expiratory carbon dioxide were measured every 5 minutes. Respiratory compliance (Crs) was computed. PEEPi was measured (end-expiratory occlusion method). Main Results PEEPi ≥ 5 cm H2O occurred in 14 patients (27%) after intubation, in 16 (30%) at the beginning, and in 14 (27.3%) at the end of surgery. Thirty-one patients (59.4%) exhibited PEEPi ≥ 5 cm H2O on at least 1 time point. PEEPi at the beginning of surgery was positively correlated with Pawplateau, Crs, tidal volume, and body mass index. Body mass index was the only predictor for the occurrence of PEEPi ≥ 5 cm H2O. At the beginning of surgery, the Pawplateau receiver operating characteristic curve predicting PEEPi ≥ 5 cm H2O had area under the receiver operating characteristic curve of 0.85; best cutoff value of 15.5 cm H2O (sensitivity, 88.9%; specificity, 75%; correctly classified cases, 86.1%). When PEEPe was applied, in 23 cases (82.1%), total PEEP equaled PEEPe+ PEEPi; in 3 (10.7%), it was lower; and in 2 (7.1%), it was higher. Application of PEEPe increased SpO2 (Prs (Pi (mostly due to dynamic hyperinflation) is common. Hemodynamic complications, barotrauma, and O2 desaturation (reversible with PEEPe) are rare. Pawplateau provided by ventilators is useful in suspecting and monitoring the occurrence of PEEPi and allows detection of lung overdistension as PEEPe is applied.
AB - Study Objective To assess the safety of mechanical ventilation and effectiveness of extrinsic positive end-expiratory pressure (PEEP) (PEEPe) in improving peripheral oxygen saturation (SpO2) during direct microlaryngeal laser surgery; to assess the incidence, amount, and nature (dynamic hyperinflation or airflow obstruction) of ensuing intrinsic PEEP (PEEPi); and to find a surrogate PEEPi indicator. Design Quasiexperimental. Setting S. Raffaele Hospital (Milano), November 2009 to December 2010. Patients Fifty-two adults scheduled for direct microlaryngeal laser surgery. Exclusion criterion is pregnancy. Interventions Twenty-one percent O2 mechanical ventilation through 4.5- to 5.5-mm internal diameter endotracheal tubes; in 29 patients, after measurement of PEEPi, an identical amount of PEEPe was added; and PEEPi. Measurements SpO2, peak (Pawpeak) and plateau (Pawplateau) airway pressure, and end-expiratory carbon dioxide were measured every 5 minutes. Respiratory compliance (Crs) was computed. PEEPi was measured (end-expiratory occlusion method). Main Results PEEPi ≥ 5 cm H2O occurred in 14 patients (27%) after intubation, in 16 (30%) at the beginning, and in 14 (27.3%) at the end of surgery. Thirty-one patients (59.4%) exhibited PEEPi ≥ 5 cm H2O on at least 1 time point. PEEPi at the beginning of surgery was positively correlated with Pawplateau, Crs, tidal volume, and body mass index. Body mass index was the only predictor for the occurrence of PEEPi ≥ 5 cm H2O. At the beginning of surgery, the Pawplateau receiver operating characteristic curve predicting PEEPi ≥ 5 cm H2O had area under the receiver operating characteristic curve of 0.85; best cutoff value of 15.5 cm H2O (sensitivity, 88.9%; specificity, 75%; correctly classified cases, 86.1%). When PEEPe was applied, in 23 cases (82.1%), total PEEP equaled PEEPe+ PEEPi; in 3 (10.7%), it was lower; and in 2 (7.1%), it was higher. Application of PEEPe increased SpO2 (Prs (Pi (mostly due to dynamic hyperinflation) is common. Hemodynamic complications, barotrauma, and O2 desaturation (reversible with PEEPe) are rare. Pawplateau provided by ventilators is useful in suspecting and monitoring the occurrence of PEEPi and allows detection of lung overdistension as PEEPe is applied.
KW - Airflow obstruction
KW - Barotauma
KW - Intrinsic PEEP
KW - Mechanical ventilation
KW - Pulmonary dynamic hyperinflation
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U2 - 10.1016/j.jclinane.2016.01.029
DO - 10.1016/j.jclinane.2016.01.029
M3 - Article
AN - SCOPUS:84963533252
VL - 31
SP - 124
EP - 130
JO - Journal of Clinical Anesthesia
JF - Journal of Clinical Anesthesia
SN - 0952-8180
ER -