Mechanical ventilation in patients with acute hypoxemic respiratory failure

Objective: To describe the clinical characteristics of patients with AHRF (without ARDS) hospitalized in the ICU who require IMV. To evaluate the association between mortality and different variables. Design: Inception cohort. Scope: This study was conducted in two Argentine ICUs from the private health sector between 07/01/2013 and 12/31/2014. Patients: From a consecutive sample of 2526 patients, 229 individuals aged 18 and upwards were included in the study; they were admitted to the ICU requiring IMV for over 24 hours and developed AHRF (without ARDS). Primary endpoints: Demographic variables and variables associated with the number of days with IMV and at the ICU were documented, as well as the initial setting of the respirator, monitoring variables and evolution at discharge. Likewise, the number and type of complications developed during the period of IMV were documented. Results: 70.7% of admissions were for medical reasons. SAPS II score was 42. The period of IMV and at the ICU was higher in patients with delirium (p<0.0001 in both). In the logistic regression model adjusted by the severity of hypoxemia, age (OR 1.02; 95% CI 1.002-1.04: p = 0.033) and shock (OR 2.37; 95% CI 1.12-5: p = 0.023) acted as independent predictors of mortality. Conclusions: In this group of patients who required IMV for over 24 hours and who developed AHRF (without ARDS) there was a demographic distribution similar to that described in other reports. Mortality was not associated with the severity of hypoxemia, whereas shock and age were independent predictors of mortality.

High-frequency oscillatory ventilation in children with hematologic neoplasms and other causes induced acute hypoxic respiratory failure / 中国小儿急救医学

Objective To evaluate the significance of high-frequency oscillatory ventilation(HFOV) used in acute hypoxic respiratory failure(AHRF) children,failing to conventional ventilation.Methods This was a retrospective study of AHRF children ventilated by HFOV from January 2011 to September,2013.All patients were initially treated by conventional mechanical ventilation (CMV),and changed to be treated by HFOV if the patient met to one of the following criteria after the CMV parameters of PIP ＞ 30 mmH2O(1cmH2O =0.098 kPa) or PEEP ＞ 10 cmH2O with FiO2 100％ ∶ (1) SpO2 ＜ 90％ or PaO2 ＜ 60 mmHg (1 mmHg =0.133 kPa) ; (2) severe respiratory acidosis (PaCO2 ＞ 80 mmHg) ; (3) serious air leakage (mediastinal emphysema or pneumothorax).The following parameters were recorded:patient's gender,age,living PICU time,CMV ventilation time,HFOV ventilation time.We reviewed ventilation parameter settings (MAP,△P,F,FiO2),oxygenation index(PaO2/FiO2,OI),arterial blood gas,heart rate,blood pressure at different time points including late CMV(H0),2 h after HFOV(H2),6 h after HFOV(H6),12 h after HFOV(H12),24 h after HFOV (H24) and 48 h after HFOV (H48),respectively.Various indexes at different time points were compared between survival group and death group,oncology group and no-oncology group.Results PaO2 at H2 compared with H0 had significant improvement[76.9(61.9 ～ 128.0) mmHg vs 50.1 (49.5 ～68.0) mmHg,P =0.006] . PaO2/FiO2 at H2,H48 had significant improvement compared with those at H0,H24 [94.9(66.8 ～ 138.9) mmHg vs 68.0(49.5 ～86.8) mmHg,P=0.039; 135.0(77.6～240.0) mmHg vs 90.7 (54.6 ～161.7) mmHg,P =0.023)].All children's systolic pressure,diastolic blood pressure,heart rate at various time points had no difference (P ＞0.05).Compared to death group(n =14),PaO2/FiO2,OI at H6,H12,H24,H48 in survival group (n =9) had significant improvement(P ＜ 0.05).Compared to oncology group (n =10),OI at H2,H6 in no-oncology group(n =10) had significant improvement [(19.2 (13.9 ～ 26.6) vs 33.8 (19.7 ～ 48.3),P =0.049 ; 16.0(8.4 ～27.1) vs 28.9(20.9 ～38.9),P =0.027)],and mean airway pressure between two groups at H2,H6,H12 had significant improvement(P ＜ 0.05).Mortality had no significant differcence between two groups (4/10 vs 10/13,P =0.086).Conelusion HFOV used in children with AHRF which had failed with CMV ventilation can improve the patient's PaO2 and OI.Heart rate and blood pressure are stable during HFOV treatment.Oncology group patients needed higher initial MAP to improve oxygenation than no-oncology group patients when changed to HFOV treatment,but the mortality showed no difference between two groups.

Airway Pressure Release Ventilation: An Alternative Ventilation Mode for Pediatric Acute Hypoxemic Respiratory Failure.

Airway pressure release ventilation (APRV) is a relatively new mode of mechanical ventilation. The use of this model of ventilation in pediatrics has been limited. The authors describe their experience with this mode of ventilation in a series of pediatric hypoxemic respiratory failure patients. Three patients with acute hypoxemic respiratory failure (AHRF) were treated with APRV, when oxygenation did not improve with pressure control ventilation (PCV). The mean age of the patients was 5.8± 1.3 months. Fractional oxygen concentration decreased from 0.97±0.02 for PCV to 0.68±0.12 for APRV, peak airway pressure fell from 36.6±11.5 cm H2O for PCV to 33.3±5.7 cm H2O for APRV, mean airway pressure increased from 17.9±5.9 cmH2O for PCV to 27± 2.6 cmH2O for APRV and release tidal volume increased from 8.3±1.5 mL/kg for PCV to 13.2±1.1 mL/kg for APRV after 1 h. APRV may improve oxygenation in pediatric AHRF when conventional mechanical ventilation fails. The APRV modality may provide better oxygenation with lower peak airway pressure.