Exploration of Indications of Mechanical Ventilation for Asthmatic Attacks

Objective To compare the values of blood gas analysis,lactic acid and APACHEⅡscore as indications of mechanical ventilation for asthmatic attacks.Methods A retrospective case-control study was used to examine the sensitivity,specificity and Youden′s index of blood gas analysis (pH,PaO_2,PaCO_2),blood lactate,different standards of APACHE II score for 15 asthmatic patients with severe attacks,who needed mechanical ventilation (case group) and 78 asthmatic patients with moderate or severe attacks,who didn′t need mechanical ventilation (control group).The biggest break point of Youden′s index was chosen as the indication of mechanical ventilation.Results There are different indexes judging the truthfulness of mechanical ventilation:the sensitivity,specificity and Youden′s index of pH7.35 were 86.7%,100% and 0.87,respectively;the sensitivity,specificity and Youden′s index of PaCO_245 mm Hg were 93.3%,93.6% and 0.87,respectively;the sensitivity,specificity and Youden′s index of lactic acid 2.0mmol/L were 80.0%,89.7% and 0.70,respectively;the sensitivity,specificity and Youden′s index of APACHEⅡscore≥12 were 100%,89.7% and 0.90,respectively.Conclusion APACHEⅡscore≥12,pH7.35 and PaCO_2 45 mm Hg can be used as the indications of mechanical ventilation for asthmatic attacks.