Figure 1

The phases-of-illness paradigm. Patients enter the ICU environment for one of two reasons: resuscitation (organ support, including respiratory failure, shock states, acute liver failure, and so on) or ICU monitoring. Patients who need resuscitation are in shock and need aggressively titrated and carefully monitored care. Patients who need monitoring are typically 'stable', but need a higher level of observation than is available elsewhere in the hospital: hourly checks or interventions, invasive monitors, and so on. Movement through the continuum of phases is fluid, timeless, and directionless. A patient getting better will move to the right and a patient getting worse to the left. Since a severity of illness may describe any type of patient, and supportive care goals (Table 1) apply to all patients with a certain severity of illness, additional 'disease-specific' protocols may also apply to a patient. Phase specific protocols or checks in this table are examples only: these objectives and do-confirm type checks must be adapted to fit a local environment and culture. The 'pause cloud' is an 'in-between' phase during which it is unclear what 'direction' a patient is moving (that is, could be getting better or worse). Typically, monitoring may increase, decrease, or stay the same as the patient's current phase. Sometimes this phase may be a brief 'check' (check another set of labs, check an imaging study, check cultures, and so on). Sometimes it may be more prolonged (for example, during traumatic brain injury (TBI) when intracranial pressure (ICP) management is ongoing but unchanging). ABG, arterial blood gas; AC mode, pressure or volume assist control mode of ventilation; AKI, acute kidney injury; ALI, acute lung injury; APRV, airway pressure release ventilation; ARDS, acute respiratory distress syndrome; BiPAP, bi-level pressure consisting of inspiratory and expiratory positive airway pressure; CBC, complete blood count; CIN, contrast-induced nephropathy; CPAP, continuous positive airway pressure; CRP, C-reactive protein; DSH, daily sedation holiday; DVT, deep vein thrombosus; ECMO, extracorporeal membrane oxygenation; GI, gastrointestinal; HFOV, high frequency oscillatory ventilation; IBW, ideal body weight; ICP, intracranial pressure; IVC, inferior vena cava; LFT, liver functions test; NPO, noting per os (nothing to eat by mouth); PE, pulmonary embolism; PEEP, positive end expiratory pressure; Pplat, plateau pressure; PRN, as needed; PS, pressure support; PT/PTT, prothrombin time/partial thromboplastin time; P-V loop, pressure volume loop; SBT, spontaneous breathing trial; ScvO2/SvO2, central vein oxygen saturation/mixed venous oxygen saturation; SpO2, peripheral oxygen saturation; TBI, traumatic brain injury; TEG, thromboelastogram; TPN, total parenteral nutrition; TTE, transthoracic echocardiogram; UUN, urine urea nitrogen; VILI, ventilator induced lung injury.