Too many ventilator modes!

Clinicians responsible for ventilator care are often perplexed by the number of modes available on modern critical care ventilators. Modes that seem identical perform differently, different modes perform identically, and seemingly identical modes can differ under certain conditions. 1 Even the term " assisting " can refer to the patient triggering the ventilator or the ventilator assisting the patient. 2 As confusion about modes could lead to clinical errors, how did this problem develop? Modern intensive care unit (ICU) ventilators (8 models by my count) are complex high-technology machines manufactured in a competitive environment. As such, a machine is designed to be better and different than its competitors. Ventilator development requires 2 types of engineers: hardware engineers (putting transducers and so-lenoids into a box), and software engineers (geeks writing code). Basically, these machines are an integrated system of sensors, graphic displays, and solenoids (with feedback between them) that are, ultimately, controlled by a clini-cian. As an engineer-friend explained, a ventilator is similar to an aircraft, and controlling an aircraft requires a knowledgeable pilot (or clinician). Over the years, each ventilator has been improved by adding enhanced hardware and refining the pneumatic/ electronic circuitry. The point is, hardware differs between machines. Software engineers write complex code that controls solenoid performance based on sensor and clinician inputs. Software algorithms differ markedly between machines. As well, companies retain clinical experts to recommend mode improvements. Incorporating new modes requires FDA approval, which becomes an expensive, lengthy process. Protecting the investment includes patent submissions and copyrights of the product name, its features , and, quite often, the modes. Therefore, modes are truly different between ventilators, and their names are often proprietary. But modes may not be clinically different. Understanding that performance differs between ventilators , test lung studies have been conducted to compare and contrast modes. Marchese et al recently evaluated mode differences between 6 ICU ventilators, concluding that the ventilators performed acceptably, but some performed inadequately with specific settings. 3 In an evaluation of 7 home care ventilators, Blakeman et al found wide variability in battery duration and triggering sensitivity between machines. 4 High respiratory rate and low tidal volume conditions presented problems for 2 of the ventilators. Evaluating whether technical differences between machines are of clinical importance is a responsibility of the clini-cian. The difficult-to-ventilate patient might benefit from a specific mode under a particular condition compared to, for example, the option of …