The two subtypes of ARDS respond differently to therapeutic interventions such as alterations in positive end-expiratory pressure, prone ventilation, and recruitment maneuvers [9 13].
Response to PEEP levels of 20,17,14,11, 8, and 5 cmH2O was evaluated under four conditions: supine, high abdominal pressure; prone, high abdominal pressure; supine, low abdominal pressure; and prone, low abdominal pressure.
One explanation for this is that some patients remain severely hypoxemic despite mechanical ventilation conducted according to current international recommendations including, in particular, the use of a tidal volume of between 4 and 8 mL/kg, alveolar recruitment by use of high positive expiratory pressure, prone positioning and early administration of a neuromuscular blocking agent [2].
Other approaches such as high levels of positive end-expiratory pressure, prone positioning, and recruitment maneuvers appear to improve hypoxemia but have not yet been shown to reduce mortality [ 3].
One explanation for this is that some patients remain severely hypoxemic despite mechanical ventilation conducted according to current international recommendations including, in particular, the use of a tidal volume of between 4 and 8 mL/kg, alveolar recruitment by use of high positive expiratory pressure, prone positioning and early administration of a neuromuscular blocking agent [ 2].
C, control group; HVLP-P, high volume-low positive end-expiratory pressure, prone; HVLP-S, high volume-low positive end-expiratory pressure, supine; logpcIII: logarithmic transformation of the expression of PC III mRNA normalized by GAPDH mRNA; LVHP-S, low volume-high positive end-expiratory pressure, supine; NIR, no injury, recruited; OA, oleic acid injury, no ventilation.
This association suggests that those with a prehypertension (pre-HTN) blood pressure are prone to progress to HTN [ 6].
Other adjunctive strategies, including maintenance of high positive end-expiratory pressure and prone positioning, have not shown any beneficial effect on outcome [ 39, 40].
Finally, animal models have shown that, for the same pattern of ventilatory pressures, the prone position protects better against ventilator-induced lung injury [ 8].
Broccard and colleagues have also shown in animal models that, for the same pattern of ventilatory pressures, the prone position protects better against VILI [ 15].
In fact, Hope et al. recently evaluated the validity of this method in patients with diabetes and found that estimation of central pressures was prone to substantially greater error in this population [ 26].
