A multivariate prognostic score for predicting mortality of acquired immunodeficiency syndrome patients with Hypoxemic Respiratory Failure and Pneumocystis Jiroveci Pneumonia

Background Severe hypoxemic respiratory failure (SHRF) due to Pneumocystis jiroveci pneumonia (PJP) in AIDS patients represents the main cause of admission and mortality in respiratory intensive care units (RICUs) in low- and middle-income countries. Objective The objective of this study was to develop a predictive scoring system to estimate the risk of mortality in HIV/AIDS patients with PJP and SHRF. Methods We analyzed data of patients admitted to the RICU between January 2013 and January 2018 with a diagnosis of HIV infection and PJP. Multivariate logistic regression and Kaplan–Meier method were used in data analysis. The RICU and inhospital mortality were 25% and 26%, respectively. Multivariate analysis identified four independent predictors: body mass index, albumin, time to ICU admission, and days of vasopressor support. A predictive scoring system was derived and validated internally. The discrimination was 0.869 (95% confidence interval: 0.821-0.917) and calibration intercept (α) and slope (β) were 0.03 and 0.99, respectively. The sensitivity was 47.2%, specificity was 84.6%, positive predictive value was 89.2%, and negative predictive value was 82.6%. Conclusions This scoring system is a potentially useful tool to assist clinicians, in low- and medium-income countries, in estimating the RICU and inhospital mortality risk in patients with HIV/AIDS and SHRF caused by PJP.

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.

Realidad de la circulación de membrana extracorpórea neonatal en Colombia: descripción de los primeros casos / Current state of neonatal extracorporeal membrane oxygenation in Colombia: description of the first cases

La oxigenación de membrana extracorpórea se considera una terapia de rescate y soporte vital compleja, con beneficios en enfermedades cardiorrespiratorias durante el periodo neonatal, que cumple con las características de ser reversible en recién nacidos mayores de 34 semanas. El criterio de selección de los pacientes y el momento oportuno en que se indica son críticos para el resultado final, si bien las nuevas alternativas de manejo en falla respiratoria hipoxémica en recién nacidos a término y casi a término han generado una disminución de su uso, excepto en la hernia diafragmática, que continúa siendo una enfermedad compleja donde podría tener alguna aplicabilidad. Si bien nuestra experiencia está iniciándose, el entrenamiento constante hará de la oxigenación de membrana extracorpórea una opción para pacientes complejos en quienes la terapia máxima fracasa. Se hace un informe de los primeros casos neonatales por falla respiratoria hipoxémica manejados en la Fundación Cardiovascular de Colombia.

Extracorporeal membrane oxygenation is considered a rescue therapy and complex vital support with benefits in cardiorespiratory diseases during neonatal period that fulfil the characteristics of being reversible in neonates older than 34 weeks. The criteria for patient selection and its prompt use are critical for the final result. Even though new alternatives for management of hypoxemic respiratory failure in full term and almost full term neonates have decreased its use, congenital diaphragmatic hernia continues being a complex disease where it can have some applicability. Even though our experience is beginning, constant training will make of extracorporeal membrane oxygenation an option for complex patients in whom maximum therapy fails. This is a report of the first neonatal cases of hypoxemic respiratory failure managed at Fundación Cardiovascular de Colombia.

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.

Mechanical Ventilation of the Children / 소아과

Mechanical ventilation in children has some differences compared to in neonates or in adults. The indication of mechanical ventilation can be classified into two groups, hypercapnic respiratory failure and hypoxemic respiratory failure. The strategies of mechanical ventilation should be different in these two groups. In hypercapnic respiratory failure, volume target ventilation with constant flow is favorable and pressure target ventilation with constant pressure is preferred in hypoxemic respiratory failure. For oxygenation, fraction of inspired oxygen (FiO2) and mean airway pressure (MAP) can be adjusted. MAP is more important than FiO2. Positive end expiratory pressure (PEEP) is the most potent determinant of MAP. The optimal relationship of FiO2 and PEEP is PEEP = FiO2 x 20. For ventilation, minute volume of ventilation (MV) product of tidal volume (TV) and ventilation frequency is the most important factor. TV has an maximum value up to 15 mL/kg to avoid the volutrauma, so ventilation frequency is more important. The time constant (TC) in children is usually 0.15-0.2. Adequate inspiratory time is 3TC, and expiratory time should be more than 5TC. In some severe respiratory failure, to get 8TC for one cycle is impossible because of higher frequency. In such case, permissive hypercapnia can be considered. The strategy of mechanical ventilation should be adjusted gradually even in the same patient according to the status of the patient. Mechanical ventilators and ventilation modes are progressing with advances in engineering. But the most important thing in mechanical ventilation is profound understanding about the basic pulmonary mechanics and classic ventilation modes.