RESUMO
Elderly patients (over age 85) are increasingly treated in Intensive Care Units (ICU), despite doctors' reluctance to accept these frail patients. There are only few studies describing the relevance of treatments for this group of patients in ICU. One of these studies defined an age of 85 or over as the essential admittance criterion. Exclusion criteriwere low autonomy before admittance or an inability to answer the phone. Epidemiological data, history, lifestyle, and autonomy (ADL score of six items) were recorded during admission to the ICU and by phone interviews six months later. Eight French ICUs included 239 patients aged over 85. The most common diagnostics were non-cardiogenic lung disease (36%), severe sepsis/septic shock (29%), and acute pulmonary oedem (28%). Twenty-three percent of patients were dependent at the time of their admission. Seventy-one percent of patients were still alive when released from ICU, and 52% were still alive after 6 months. Among the patients which were non-dependent before hospitalization, 17% became dependent. The only prognostic criterifound were the SAPS II score on admission and the place of residence before admission (nursing home or family environment had poor prognosis). Although the prognosis of these elderly patients was good after hospitalization in ICU, it should be noted that the population was carefully selected as having few comorbidities or dependence. No triage critericould be suggested.
RESUMO
BACKGROUND: Complexity and functions of automated medical devices used to support life (eg, ventilators, dialysis machines, monitors, insulin pump with continuous blood glucose monitoring system, etc.) increase over time. Until recently, devices were partially automated by very simple feedback loops, with no or few software dependence (such as the simplest home thermostat). For the last two decades, devices have been increasingly driven by complex algorithms devoted to improve patient's treatment and monitoring as well as users experience. METHODS: We report the unexpected and inappropriate operation of two recent ventilators, associated to potential harmful consequences. We provide both a description of the clinical situations (five ICU patients, archetypal situations) and a test bench analysis. RESULTS: While set in volume mode, these ventilators activated an algorithm dedicated to limit airway pressure when an increase in airway resistance occurred. In such situations, a pressure-like mode was activated (with decelerating inspiratory flow and set pressure, with target of volume). The main consequences observed were that the tidal volume was no longer guaranteed or delivered and that the pressure limitation operated by the algorithm prevented the airway pressure from reaching the high-pressure alarm threshold. CONCLUSION: This led to the silent takeover of commands by the ventilator without clinicians or nurses being aware of it and without any warnings or alarms emission adapted to the severity of the event. Generally speaking, such an algorithm questions the place of automation and its limit when users are not aware of its presence as well as the need for regulation and additional tests before its implementation. Intensivists and respiratory care specialists should remain vigilant regarding the risk of rare but critical events related to unexpected functioning or insufficiently tested equipment during the pre-clinical development phases. They should not neglect misunderstood critical events without having performed sufficient investigations.
