Some more recently developed tests, such as the end-expiratory occlusion test, the 'mini' fluid challenge and the PLR test can be used as alternative methods, solving the problem of prediction of volume responsiveness in cases of spontaneous breathing activity and/or cardiac arrhythmias.
Also, prediction of responsiveness can be important in case of gradient-elution LC MS and LC MS/MS methods in which instrumental conditions are varied during time.
In case of fluid responsiveness, PLR increased venous return by increasing Psm to a larger extent than CVP.
This indicates that immortalization changes the responsiveness of keratinocytes to various stimuli, as it has been demonstrated in case of neuropeptides [63], [66].
For example, how is initial inpatient treatment modified in case of patients presenting to the emergency department after non-responsiveness to prior outpatient treatment?
In case of the AKT inhibitor perifosine, three cell lines showed a high or intermediate responsiveness to the drug while one cell line was resistant.
Second, testing fluid responsiveness makes sense only in cases of circulatory failure (Fig. 2).
For instance, in patients where acute circulatory failure and ARDS coexist, one should limit fluid administration even in cases of preload responsiveness because of the severity of lung injury [21], as assessed by increased lung water and by alteration of pulmonary vascular permeability [88].
In the case of low tidal volume, the small variations in intrathoracic pressure may not be sufficient to trigger significant preload variations, even in cases of preload responsiveness.
