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Uso de los análisis de formas de onda del respirador para detectar asincronías entre el paciente y el respirador. La hoja de referencia

Asincronías. Discrepancia entre el paciente y el respirador

Las asincronías entre el paciente y el respirador son discrepancias entre los tiempos inspiratorio y espiratorio del paciente y el respirador. Un modo habitual de detectar estas asincronías es examinando las formas de onda del respirador. Existen distintos tipos de asincronías, cada una con unas peculiaridades propias que son visualmente identificables. Un ojo bien entrenado puede detectar asincronías analizando las formas de onda de flujo o presión (Tassaux D, Gainnier M, Battisti A, Jolliet P. Impact of expiratory trigger setting on delayed cycling and inspiratory muscle workload. Am J Respir Crit Care Med. 2005;172(10):1283-1289. doi:10.1164/rccm.200407-880OC1, Thille AW, Rodriguez P, Cabello B, Lellouche F, Brochard L. Patient-ventilator asynchrony during assisted mechanical ventilation. Intensive Care Med. 2006;32(10):1515-1522. doi:10.1007/s00134-006-0301-82, Blanch L, Villagra A, Sales B, et al. Asynchronies during mechanical ventilation are associated with mortality. Intensive Care Med. 2015;41(4):633-641. doi:10.1007/s00134-015-3692-63, Mojoli et al. Automatic monitoring of plateau and driving pressure during pressure and volume controlled ventilation. Intensive Care Medicine Experimental 2015 3(Suppl 1):A998.4).

Hojas de referencia de asincronías Hojas de referencia de asincronías

La hoja de referencia. El documento de consulta para detectar asincronías entre el paciente y el respirador

Como ayuda para reconocer las peculiaridades que distinguen a cada tipo de asincronía, hemos elaborado una hoja de referencia (u "hoja de referencia") de dos páginas que puede descargar abajo.

Con ella, obtendrá rápidamente información como la siguiente:

  • Los 7 tipos de asincronía principales

  • Indicaciones de los datos que deben observarse al examinar las formas de onda de flujo o presión

  • Un ejemplo visual de la forma de onda con la característica más representativa resaltada

  • Posibles causas habituales de los diferentes tipos de asincronía

No deje que pase desapercibida ninguna asincronía entre el paciente y el respirador. Envíe el formulario para recibir la hoja de referencia

No deje escapar la oportunidad de mejorar sus conocimientos sobre ventilación mecánica.

Impact of expiratory trigger setting on delayed cycling and inspiratory muscle workload.

Tassaux D, Gainnier M, Battisti A, Jolliet P. Impact of expiratory trigger setting on delayed cycling and inspiratory muscle workload. Am J Respir Crit Care Med. 2005;172(10):1283-1289. doi:10.1164/rccm.200407-880OC



RATIONALE

During pressure-support ventilation, the ventilator cycles into expiration when inspiratory flow decreases to a given percentage of peak inspiratory flow ("expiratory trigger"). In obstructive disease, the slower rise and decrease of inspiratory flow entails delayed cycling, an increase in intrinsic positive end-expiratory pressure, and nontriggering breaths.

OBJECTIVES

We hypothesized that setting expiratory trigger at a higher than usual percentage of peak inspiratory flow would attenuate the adverse effects of delayed cycling.

METHODS

Ten intubated patients with obstructive disease undergoing pressure support were studied at expiratory trigger settings of 10, 25, 50, and 70% of peak inspiratory flow.

MEASUREMENTS

Continuous recording of diaphragmatic EMG activity with surface electrodes, and esophageal and gastric pressures with a dual-balloon nasogastric tube.

MAIN RESULTS

Compared with expiratory trigger 10, expiratory trigger 70 reduced the magnitude of delayed cycling (0.25 +/- 0.18 vs. 1.26 +/- 0.72 s, p < 0.05), intrinsic positive end-expiratory pressure (4.8 +/- 1.9 vs. 6.5 +/- 2.2 cm H(2)O, p < 0.05), nontriggering breaths (2 +/- 3 vs. 9 +/- 5 breaths/min, p < 0.05), and triggering pressure-time product (0.9 +/- 0.8 vs. 2.1 +/- 0.7 cm H2O . s, p < 0.05).

CONCLUSIONS

Setting expiratory trigger at a higher percentage of peak inspiratory flow in patients with obstructive disease during pressure support improves patient-ventilator synchrony and reduces inspiratory muscle effort. Further studies should explore whether these effects can influence patient outcome.

Patient-ventilator asynchrony during assisted mechanical ventilation.

Thille AW, Rodriguez P, Cabello B, Lellouche F, Brochard L. Patient-ventilator asynchrony during assisted mechanical ventilation. Intensive Care Med. 2006;32(10):1515-1522. doi:10.1007/s00134-006-0301-8



OBJECTIVE

The incidence, pathophysiology, and consequences of patient-ventilator asynchrony are poorly known. We assessed the incidence of patient-ventilator asynchrony during assisted mechanical ventilation and we identified associated factors.

METHODS

Sixty-two consecutive patients requiring mechanical ventilation for more than 24 h were included prospectively as soon as they triggered all ventilator breaths: assist-control ventilation (ACV) in 11 and pressure-support ventilation (PSV) in 51.

MEASUREMENTS

Gross asynchrony detected visually on 30-min recordings of flow and airway pressure was quantified using an asynchrony index.

RESULTS

Fifteen patients (24%) had an asynchrony index greater than 10% of respiratory efforts. Ineffective triggering and double-triggering were the two main asynchrony patterns. Asynchrony existed during both ACV and PSV, with a median number of episodes per patient of 72 (range 13-215) vs. 16 (4-47) in 30 min, respectively (p=0.04). Double-triggering was more common during ACV than during PSV, but no difference was found for ineffective triggering. Ineffective triggering was associated with a less sensitive inspiratory trigger, higher level of pressure support (15 cmH(2)O, IQR 12-16, vs. 17.5, IQR 16-20), higher tidal volume, and higher pH. A high incidence of asynchrony was also associated with a longer duration of mechanical ventilation (7.5 days, IQR 3-20, vs. 25.5, IQR 9.5-42.5).

CONCLUSIONS

One-fourth of patients exhibit a high incidence of asynchrony during assisted ventilation. Such a high incidence is associated with a prolonged duration of mechanical ventilation. Patients with frequent ineffective triggering may receive excessive levels of ventilatory support.

Asynchronies during mechanical ventilation are associated with mortality.

Blanch L, Villagra A, Sales B, et al. Asynchronies during mechanical ventilation are associated with mortality. Intensive Care Med. 2015;41(4):633-641. doi:10.1007/s00134-015-3692-6



PURPOSE

This study aimed to assess the prevalence and time course of asynchronies during mechanical ventilation (MV).

METHODS

Prospective, noninterventional observational study of 50 patients admitted to intensive care unit (ICU) beds equipped with Better Care™ software throughout MV. The software distinguished ventilatory modes and detected ineffective inspiratory efforts during expiration (IEE), double-triggering, aborted inspirations, and short and prolonged cycling to compute the asynchrony index (AI) for each hour. We analyzed 7,027 h of MV comprising 8,731,981 breaths.

RESULTS

Asynchronies were detected in all patients and in all ventilator modes. The median AI was 3.41 % [IQR 1.95-5.77]; the most common asynchrony overall and in each mode was IEE [2.38 % (IQR 1.36-3.61)]. Asynchronies were less frequent from 12 pm to 6 am [1.69 % (IQR 0.47-4.78)]. In the hours where more than 90 % of breaths were machine-triggered, the median AI decreased, but asynchronies were still present. When we compared patients with AI > 10 vs AI ≤ 10 %, we found similar reintubation and tracheostomy rates but higher ICU and hospital mortality and a trend toward longer duration of MV in patients with an AI above the cutoff.

CONCLUSIONS

Asynchronies are common throughout MV, occurring in all MV modes, and more frequently during the daytime. Further studies should determine whether asynchronies are a marker for or a cause of mortality.

Automatic monitoring of plateau and driving pressure during pressure and volume controlled ventilation

Mojoli et al. Automatic monitoring of plateau and driving pressure during pressure and volume controlled ventilation. Intensive Care Medicine Experimental 2015 3(Suppl 1):A998.