After application of inclusion and exclusion criteria, 1 RCT and 5 observational trials were included in evidence evaluation. For the critical outcome of vital signs, we identified 1 RCT and 5 observational trials.In Normotensive Subjects (P), Passive Leg Raising to 60° for 5 Minutes (I) Compared With Supine Position (C)We identified very-low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 observational study(Kyriakides 1994, 288) enrolling 43 subjects (12 healthy subjects and 31 subjects with heart disease) showing no significant changes in systolic blood pressure (SBP), diastolic blood pressure (DBP), or heart rate (HR).In Normotensive Subjects With Blood Loss (P), Passive Leg Raising to 45° for 5 Minutes (I) Compared With Supine Position for 5 Minutes (C)We identified low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 observational study(Wong 1989, 979) enrolling 27 normotensive subjects with 500 mL blood loss, showing no benefit from passive leg raising (PLR) with a nonsignificant change in mean arterial blood pressure (MAP) but a benefit from PLR, with a significant• Increase in thoracic bioimpedance cardiac index (MD, 0.8; 95% CI, 0.75–0.85) • Increase in stroke index (SI) (MD, 15.00; 95% CI, 14.46–15.54) • Decrease in HR (MD, −3; 95% CI, −3.56 to −2.44)Subjects without blood loss showed a significant increase in cardiac index with PLR (MD, 0.3; 95% CI, 0.12–0.72) but no significant change in MAP or difference in HR. In Normotensive Subjects With Blood Loss (P), Standing for 5 Minutes (I) Compared With Supine Position (C) for 5 MinutesWe identified low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 observational study(Wong 1989, 979) enrolling 27 normotensive subjects with 500 mL blood loss, showing a nonsignificant increase in MAP.The standing position showed a statistically significant decrease in cardiac index compared with supine position (MD, −0.3; 95% CI, −0.38 to −0.22), and an increase in HR (MD, 22; 95% CI, 20.84–23.16).In Normotensive Subjects (P), Supine Position for 3 Minutes Followed by PLR to 60° for 20 Seconds (I) Compared With Supine Position (C) for 3 MinutesWe identified very-low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 observational study(Gaffney 1982, 190) enrolling 10 normotensive subjects showing a benefit from the supine position plus PLR, with a significant increase in both cardiac output (CO) (MD, 0.6; 95% CI, 0.48–0.72) and stroke volume (SV) (MD, 7; 95% CI, 2.93–11.07). In Normotensive Subjects (P), Supine Position for 3 Minutes Followed by PLR to 60° for 7 Minutes (I) Compared With Supine Position for 3 Minutes (C)We identified very-low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 observational study(Gaffney 1982, 190) enrolling 10 normotensive subjects showing no significant difference in MAP, CO, or HR. Thus, improvements in CO and SV seen with PLR at 20 seconds disappeared by 7 minutes.In Normotensive Subjects (P), PLR to 60° for 1 Minute (I) Compared With Supine Position (C)We identified very-low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 observational study(Kamran 2010, 284) enrolling 125 normotensive subjects. No cardiovascular benefit was shown for PLR to 60° for 1 minute.In Hypotensive Patients (P), PLR to 45° (I) for 2 Minutes Compared With Semirecumbent (Head at 45°) for 2 Minutes (C)We identified low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 RCT(Jabot 2009, 85) enrolling 35 hypotensive subjects. No difference was found in HR, but a statistically significant benefit with PLR was demonstrated with• An increase in MAP (median difference 7 higher, CI not estimable)• An increase in SBP (median difference 12 higher, CI not estimable)• An increase in central venous pressure (CVP) (median difference 2 higher, CI not estimable) In Hypotensive Patients (P), Supine Position (C) for 2 Minutes Compared With Semirecumbent (Head at 45°) for 2 Minutes (I)We identified low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 RCT(Jabot 2009, 85) enrolling 35 hypotensive subjects. Placing patients in the supine position for 2 minutes compared with a semirecumbent 45° position failed to show any benefit for MAP, SBP, or HR. A significant increase in CVP was reported with transfer from semirecumbent to supine position (median difference 1 higher, CI not estimable).In Hypotensive Patients (P), PLR to 45° for 2 Minutes (I) Compared With Supine for 2 Minutes (C)We identified very-low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 RCT(Jabot 2009, 85) enrolling 35 hypotensive subjects. No difference was noted for HR, but a statistically significant benefit with PLR was shown with • An increase in MAP (median difference 5 higher, CI not estimable) • An increase in systolic arterial pressure (SAP) (median difference 8 higher, CI not estimable) • An increase in CVP (median difference 1 higher, CI not estimable) In Hypotensive Patients (P), Supine Position for 4 Minutes (C) Compared With PLR to 45° for 4 Minutes (I)We identified very-low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 observational study(Boulain 2002, 1245) enrolling 15 hypotensive subjects. No statistically significant difference in MAP or HR was shown between the supine position and PLR to 45° for 4 minutes. A statistically significant decrease in SAP was found for change in position from PLR to supine (MD, −4; 95% CI, −16.88 to 8.88) and for diastolic arterial pressure (DAP) (MD, −3; 95% CI, −14.81 to 8.81).In Hypotensive Patients (P), PLR to 45° for 4 Minutes (I) Compared With Supine for 4 Minutes (C)We identified very-low-quality evidence (downgraded for inconsistency, indirectness, and imprecision) from 1 observational study(Boulain 2002, 1245) enrolling 15 hypotensive subjects. There was no statistically significant difference in MAP or HR between PLR to 45° for 4 minutes and the supine position for 4 minutes. Statistically significant benefit with PLR was found for SAP (MD, 7; 95% CI, −10.89 to 24.89) and DAP (MD, 3.0; 95% CI, −8.47 to 14.47). We did not identify any evidence to address the critical outcomes of complications, incidence of cardiac arrest, overall mortality, or length of hospital stay.