Plateau Pressure and Driving Pressure in Volume- and Pressure-Controlled Ventilation: Comparison of Frictional and Viscoelastic Resistive Components in Pediatric Acute Respiratory Distress Syndrome.

OBJECTIVES: To examine frictional, viscoelastic, and elastic resistive components, as well threshold pressures, during volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV) in pediatric patients with acute respiratory distress syndrome (ARDS). DESIGN: Prospective cohort study. SETTING: Seven-bed PICU, Hospital El Carmen de Maipú, Chile. PATIENTS: Eighteen mechanically ventilated patients less than or equal to 15 years old undergoing neuromuscular blockade as part of management for ARDS. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All patients were in VCV mode during measurement of pulmonary mechanics, including: the first pressure drop (P1) upon reaching zero flow during the inspiratory hold, peak inspiratory pressure (PIP), plateau pressure (P PLAT ), and total positive end-expiratory pressure (tPEEP). We calculated the components of the working pressure, as defined by the following: frictional resistive = PIP-P1; viscoelastic resistive = P1-P PLAT ; purely elastic = driving pressure (ΔP) = P PLAT -tPEEP; and threshold = intrinsic PEEP. The procedures and calculations were repeated on PCV, keeping the same tidal volume and inspiratory time. Measurements in VCV were considered the gold standard. We performed Spearman correlation and Bland-Altman analysis. The median (interquartile range [IQR]) for patient age was 5 months (2-17 mo). Tidal volume was 5.7 mL/kg (5.3-6.1 mL/kg), PIP cm H 2 O 26 (23-27 cm H 2 O), P1 23 cm H 2 O (21-26 cm H 2 O), P PLAT 19 cm H 2 O (17-22 cm H 2 O), tPEEP 9 cm H 2 O (8-9 cm H 2 O), and ΔP 11 cm H 2 O (9-13 cm H 2 O) in VCV mode at baseline. There was a robust correlation (rho > 0.8) and agreement between frictional resistive, elastic, and threshold components of working pressure in both modes but not for the viscoelastic resistive component. The purely frictional resistive component was negligible. Median peak inspiratory flow with decelerating-flow was 21 (IQR, 15-26) and squared-shaped flow was 7 L/min (IQR, 6-10 L/min) ( p < 0.001). CONCLUSIONS: P PLAT , ΔP, and tPEEP can guide clinical decisions independent of the ventilatory mode. The modest purely frictional resistive component emphasizes the relevance of maintaining the same safety limits, regardless of the selected ventilatory mode. Therefore, peak inspiratory flow should be studied as a mechanism of ventilator-induced lung injury in pediatric ARDS.

Ventilatory load reduction by combined mild hypothermia and ultraprotective mechanical ventilation strategy in severe COVID-19-related acute respiratory distress syndrome: A physiological study.

We report the feasibility of a combined approach of very low low tidal volume (VT) and mild therapeutic hypothermia (MTH) to decrease the ventilatory load in a severe COVID-19-related acute respiratory distress syndrome (ARDS) cohort. Inclusion criteria was patients ≥18-years-old, severe COVID-19-related ARDS, driving pressure ∆P >15 cmH2O despite low-VT strategy, and extracorporeal therapies not available. MTH was induced with a surface cooling device aiming at 34°C. MTH was maintained for 72 h, followed by rewarming of 1°C per day. Data were shown in median (interquartile range, 25%-75%). Mixed effects analysis and Dunnett's test were used for comparisons. Seven patients were reported. Ventilatory load decreased during the first 24 h, minute ventilation (VE) decreased from 173 (170-192) to 152 (137-170) mL/kg/min (P = 0.007), and mechanical power (MP) decreased from 37 (31-40) to 29 (26-34) J/min (P = 0.03). At the end of the MTH period, the VT, P, and plateau pressure remained consistently close to 3.9 mL/kg predicted body weight, 12 and 26 cmH2O, respectively. A combined strategy of MTH and ultraprotective mechanical ventilation (MV) decreased VE and MP in severe COVID-19-related ARDS. The decreasing of ventilatory load may allow maintaining MV within safety thresholds.

Capnometry after an inspiratory breath hold, PLAT CO2 , as a surrogate for P aCO 2 ${P}_{{\mathrm{aCO}}_{2}}$ in mild to moderate pediatric acute respiratory distress syndrome: A feasibility study.

OBJECTIVE: Accurate and reliable noninvasive methods to estimate gas exchange are necessary to guide clinical decisions to avoid frequent blood samples in children with pediatric acute respiratory distress syndrome (PARDS). We aimed to investigate the correlation and agreement between end-tidal P CO 2 ${P}_{{\mathrm{CO}}_{2}}$ measured immediately after a 3-s inspiratory-hold (PLAT CO2 ) by capnometry and P aCO 2 ${P}_{{\mathrm{aCO}}_{2}}$ measured by arterial blood gases (ABG) in PARDS. DESIGN: Prospective cohort study. SETTING: Seven-bed Pediatric Intensive Care Unit, Hospital El Carmen de Maipú, Chile. PATIENTS: Thirteen mechanically ventilated patients aged ≤15 years old undergoing neuromuscular blockade as part of management for PARDS. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All patients were in volume-controlled ventilation mode. The regular end-tidal P CO 2 ( P ETCO 2 ) ${P}_{{\mathrm{CO}}_{2}}({P}_{{\mathrm{ETCO}}_{2}})$ (without the inspiratory hold) was registered immediately after the ABG sample. An inspiratory-hold of 3 s was performed for lung mechanics measurements, recording P ETCO 2 ${P}_{{\mathrm{ETCO}}_{2}}$ in the breath following the inspiratory-hold. (PLAT CO2 ). End-tidal alveolar dead space fraction (AVDSf) was calculated as [ ( P aCO 2 - P ETCO 2 ) / P aCO 2 ] $[({P}_{{\mathrm{aCO}}_{2}}\mbox{--}{P}_{{\mathrm{ETCO}}_{2}})/{P}_{{\mathrm{aCO}}_{2}}]$ and its surrogate (S)AVDSf as [ ( PLAT CO 2 - P ETCO 2 ) / PLAT CO 2 ] $[{(}_{\mathrm{PLAT}}{\mathrm{CO}}_{2}\mbox{--}{P}_{{\mathrm{ETCO}}_{2}}){/}_{\mathrm{PLAT}}{\mathrm{CO}}_{2}]$ . Measurements of P aCO 2 ${P}_{{\mathrm{aCO}}_{2}}$ were considered the gold standard. We performed concordance correlation coefficient (ρc), Spearman's correlation (rho), and Bland-Altmann's analysis (mean difference ± SD [limits of agreement, LoA]). Eleven patients were included, with a median (interquartile range) age of 5 (2-11) months. Tidal volume was 5.8 (5.7-6.3) mL/kg, PEEP 8 (6-8), driving pressure 10 (8-11), and plateau pressure 17 (17-19) cm H2 O. Forty-one paired measurements were analyzed. P aCO 2 ${P}_{{\mathrm{aCO}}_{2}}$ was higher than P ETCO 2 ${P}_{{\mathrm{ETCO}}_{2}}$ (52 mmHg [48-54] vs. 42 mmHg [38-45], p < 0.01), and there were no significant differences with PLAT CO2 (50 mmHg [46-55], p > 0.99). The concordance correlation coefficient and Spearman's correlation between P aCO 2 ${P}_{{\mathrm{aCO}}_{2}}$ and PLAT CO2 were robust (ρc = 0.80 [95% confidence interval [CI]: 0.67-0.90]; and rho = 0.80, p < 0.001.), and for P ETCO 2 ${P}_{{\mathrm{ETCO}}_{2}}$ were weak and strong (ρc = 0.27 [95% CI: 0.15-0.38]; and rho = 0.63, p < 0.01). The bias between PLAT CO2 and P aCO 2 ${P}_{{\mathrm{aCO}}_{2}}$ was -0.4 ± 3.5 mmHg (LoA -7.2 to 6.4), and between P ETCO 2 ${P}_{{\mathrm{ETCO}}_{2}}$ and P aCO 2 ${P}_{{\mathrm{aCO}}_{2}}$ was -8.5 ± 4.1 mmHg (LoA -16.6 to -0.5). The correlation between AVDSf and (S)AVDSf was moderate (rho = 0.55, p < 0.01), and the mean difference was -0.5 ± 5.6% (LoA -11.5 to 10.5). CONCLUSION: This pilot study showed the feasibility of measuring end-tidal CO2 after a 3-s end-inspiratory breath hole in pediatric patients undergoing controlled ventilation for ARDS. Encouraging preliminary results warrant further study of this technique.

Relación entre el apoyo social y las complicaciones agudas de la diabetes tipo 2: un estudio de corte transversal / Relationship Between Social Support and Acute Complications of Diabetes Type 2: A Cross-Sectional Study / Relação entre o apoio social e as complicações agudas da diabetes tipo 2: um estudo de corte transversal

Resumen Objetivo: evaluar la relación entre apoyo social y la frecuencia de pacientes con complicaciones agudas de la diabetes tipo 2. Materiales y métodos: se realizó un estudio de corte transversal en pacientes con diabetes mellitus tipo 2 que ingresaron a una clínica de tercer nivel entre 2014 y 2015. Se midió la percepción de apoyo social (media, IC 95%) con el cuestionario del estudio de desenlaces médicos de apoyo social (MOS, por su sigla en inglés) en los pacientes con y sin complicaciones agudas de la diabetes; se aplicó un modelo de regresión logística para identificar variables predictoras de complicaciones agudas. Resultados: se incluyeron 205 pacientes, de edad media 66 años, 51,2% mujeres, 56,6% de los pacientes eran casados, 50,7% con complicaciones agudas, la mayoría con apoyo social (83,6%; IC 95%, 76,1%-91,2%); la media de apoyo social global en pacientes sin complicaciones agudas fue 78,9 (76,8-88,1), con complicaciones 70,8 (68,3-73,2) para una diferencia entre grupos de 8,2 (IC 95 %, 4,9-11,4). La falta de apoyo social (P:3,581), el intervalo de glucometrías entre 177 y 309 al ingreso (P:2,930), estar casado (P:1,845) o en tratamiento con insulina (P:1,672) fueron predictores de las complicaciones agudas de la diabetes. Conclusión: los pacientes con complicaciones agudas presentaron puntajes más bajos de apoyo social. La falta de apoyo social se relacionó con otras variables sociodemográficas y clínicas para predecir el riesgo de complicaciones agudas. Debe explorarse al apoyo social como una opción para mejorar las estrategias de tratamiento en los pacientes diabéticos.

Abstract Objective: To evaluate the relationship between social support and the frequency of patients with acute complications of type 2diabetes. Materials and methods: A cross-sectional study was carried out on type 2 diabetic patients who consulted a level III hospital, between 2014 and 2015; the perception of social support (ci 95 %) was measured with the questionnaire for medical outcomes studies on social support (mos) in patients with and without acute complications of diabetes. A logistic regression model was applied to identify predictive variables for acute complications. Results: 205 patients were selected, average age 66 years old, 51,2% female, 56,6% married, 50,7% with acute complications, the majority with social support (83,6%; ci 95 %, 76,1-91,2 %); the average global social support in patients without acute complications was 78,9 (76,8-88,1), with complications 70,8 (68,3-73,2) for a group difference of 8,2; (ci 95 %, 4,9-11,4). The lack of social support (-3:3,581), the glucometry interval range between 177-309 (-3:2,930), being married (P:1,845) and insulin treatment (-:1,672) predicted acute diabetes complications. Conclusion: Patients with acute complications had lower social support scores, and the interaction between the lack of social support and sociodemographic variables predicted a risk of acute complications. Social support should be explored in diabetic patients to improve treatment strategies.

Resumo Objetivo: avaliar a relação entre apoio social e a frequência de pacientes com complicações agudas da diabetes tipo 2. Materiais e métodos: Se realizou um estudo de corte transversal em pacientes com Diabetes mellitus tipo 2 que ingressaram a uma clínica de III nível entre 2014 e 2015. Mediu-se a percepção de apoio social (média, IC95%) com o Questionário do Estudo de Desenlaces Médicos de Apoio Social (MOS) nos pacientes com e sem complicações agudas da diabetes; aplicou-se um modelo de regressão logística para identificar variáveis preditoras de complicações agudas. Resultados: incluíram-se 205 pacientes, idade mediana (p25-p75) 66 anos (56-76), 51,2% mulheres, 56,6% casados, 50,7% com complicações agudas, a maioria com apoio social (83,6%; IC95%, 76,1%-91,2%); a média de apoio social global em pacientes sem complicações agudas foi 78,9 (76,8-88,1), com complicações 70,8 (68,3-73,2) para uma diferença entre grupos de 8,2 (IC95%, 4,9-11,4). A falta de apoio social (-:3,581), o intervalo de concentração de glicose entre 177-309 ao ingresso (-:2,930), estar casado (-:1,845) ou em tratamento com insulina (-:1,672), foram preditores das complicações agudas da diabetes. Conclusão: os pacientes com complicações agudas apresentaram pontuações mais baixos de apoio social e a falta de apoio social se relacionou com outras variáveis sociodemográficas/clínicas para predizer o risco de complicações agudas. Deve explorar-se ao apoio social como uma opção para melhorar as estratégias de tratamento nos pacientes diabéticos.