Vahedian-Azimi Amir, Bashar Farshid R, Boushra Marina N, Quinn Joseph W, Miller Andrew C
Trauma Research Center, Nursing Faculty, Baqiyatallah University of Medical Sciences, Tehran, Iran.
Department of Anesthesia and Critical Care, Hamadan University of Medical Sciences, Hamadan, Iran.
Int J Crit Illn Inj Sci. 2020 Apr-Jun;10(2):99-104. doi: 10.4103/IJCIIS.IJCIIS_37_20. Epub 2020 Jun 8.
The negative inspiratory force (NIF) has been used to help clinicians predict a patient's likelihood of successful liberation from mechanical ventilation (MV). However, the utility of the traditional threshold of ≤-30 cmH O may not be appropriate for patients with chronic obstructive pulmonary disease (COPD). This study aims to define the optimal predictive NIF threshold for COPD patients.
A prospective-observational multi-center study was conducted in intensive care units of six academic medical centers. All patients had COPD and were intubated for hypercapnic respiratory failure. The process of weaning from MV was conducted according to the defined hospital protocol. NIF was measured after 120 min of spontaneous breathing trial (SBT). The sensitivity, specificity, positive, and negative predictive value (PPV, NPV), positive and negative likelihood ratios (LR+, LR-) were calculated, and the diagnostic accuracy recorded.
A total of 90 patients with COPD (39 males and 51 females) were included. Of these, 43 patients (47.8%) were successfully extubated whereas 47 patients (52.2%) failed SBT or required re-intubation ( = 0.654). The threshold value of ≤-25 cmHO offered the optimal performance in COPD patients: area under the receiver operating characteristic (ROC) curves ROC curves 0.836, sensitivity 95.0%, specificity 86.0%, PPV 84.4%, and NPV 95.6%., LR+ 6.79, LR- 0.06, and the diagnostic accuracy 90.7%.
In mechanically ventilated COPD patients with hypercapnic respiratory failure, the NIF threshold of ≤-25 cmHO was a moderate-to-good predictor for successful ventilator liberation, and outperforms the traditional threshold of ≤-30 cmHO.
负吸气力（NIF）已被用于帮助临床医生预测患者成功脱离机械通气（MV）的可能性。然而，传统的≤-30 cmH₂O阈值可能不适用于慢性阻塞性肺疾病（COPD）患者。本研究旨在确定COPD患者的最佳预测NIF阈值。
在六个学术医疗中心的重症监护病房进行了一项前瞻性观察性多中心研究。所有患者均患有COPD，并因高碳酸血症呼吸衰竭而插管。根据既定的医院方案进行脱机过程。在自主呼吸试验（SBT）120分钟后测量NIF。计算敏感性、特异性、阳性和阴性预测值（PPV、NPV）、阳性和阴性似然比（LR+、LR-），并记录诊断准确性。
共纳入90例COPD患者（男性39例，女性51例）。其中，43例患者（47.8%）成功拔管，而47例患者（52.2%）SBT失败或需要重新插管（P = 0.654）。≤-25 cmH₂O的阈值在COPD患者中表现最佳：受试者操作特征（ROC）曲线下面积为0.836，敏感性为95.0%，特异性为86.0%，PPV为84.4%，NPV为95.6%，LR+为6.79，LR-为0.0,6，诊断准确性为90.7%。
在因高碳酸血症呼吸衰竭而接受机械通气的COPD患者中，≤-25 cmH₂O的NIF阈值是成功脱机的中到良好预测指标，优于传统的≤-30 cmH₂O阈值。
