Table 1.
Characteristics of the included studies
| Study no. | Author/year | Design, setting, location, and publication language | Subjects | Preload dependency | Vasopressor used (n) | Sample size | No. of fluid expansions | Age (mean, years) | Male (n, %) | MAP at baseline (mean, mm Hg) | Tide volume (mean or median mL/kg) | PEEP (mean or median, cm H2O) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Monge García/2011 | Prospective study; mixed ICU; Spain; English | Mechanically ventilated hypotensive patients with acute circulatory failure | Yes | Yes (12) | 25 | 25 | 61 | 15 (60.0) | 58 | 8.6 | 7.9 |
| 2 | Gong/2013 | Retrospective study; ICU; China; Chinese | Mechanically ventilated patients with distributive or hypovolemic shock | Yes | Yes (unknown) | 32 | 32 | 66 | NR | NR | > 8 | NR |
| 3 | Monge García/2014 | Prospective study; mixed ICU; Spain; English | Mechanically ventilated patients with acute circulatory failure | Yes | Yes (30) | 53 | 80 | 63 | 31 (58.5) | 71 | 8 | 8 |
| 4 | Seo/2015 | Prospective study; operating room; Republic of Korea; English | Mechanically ventilated hypotensive patients receiving robot-assisted laparoscopic prostatectomy | Yes | No | 39 | 39 | 64 | 39 (100) | 64 | 8 | 8 |
| 5 | Lanchon/2017 | Retrospective study; operating room; France; English | Mechanically ventilated hypotensive surgical patients | Yes (part of patients) | No | 51 | 51 | 62 | 31 (60.8) | 56 | 8.2 | 3 |
| 6 | de Courson/2019 | Prospective study; 2 operating rooms; France; English | Mechanically ventilated hypotensive surgical patients | Yes | No | 56 | 56 | 57 | 21 (37.5) | 59 | 7.4 | 5 |
| 7 | Guarracino/2019 | Prospective study; ICU; USA; English | Mechanically ventilated hypotensive patients with sepsis or septic shock | Yes (part of patients) | Yes (unknown) | 55 | 55 | 69 | 34 (61.8) | 57 | 6–8 | NR |
| 8 | Luetrakool/2020 | Prospective study; medical ICU; Thailand; English | Mechanically ventilated ARDS patients with acute circulatory failure | Yes | Yes (12) | 12 | 23 | 61 | NR | 61 | 7.2 | 11.5 |
| Study no. | Author/year | Fluid type, volume, and duration | No. of MAP responder (n, %) | Threshold for MAP responsiveness | Technique to measure SVV | Fluid responsiveness |
|---|---|---|---|---|---|---|
| 1 | Monge García/2011 | Synthetic colloid (6% hydroxyethyl starch), 500 mL, over 30 min | 16 (64) | MAP increase ≥ 15% | Arterial waveform analysis | Presence of a stable value of SVV ≥ 10% |
| 2 | Gong/2013 | Colloid, 500 mL, within 30 min | 19 (59.4) | MAP increase ≥ 15% | PICCO | SVV > 10% |
| 3 | Monge García/2014 | Normal saline, 500 mL, within 30 min | 33 (41.2) | MAP increase ≥ 10% | Oesophageal Doppler | Cardiac output increase ≥ 10% after a 2-min leg-raising manoeuvre |
| 4 | Seo/2015 | 6% Hydroxyethyl starch, 500 mL, over 20 min | 17 (43.6) | MAP increase ≥ 15% | Arterial waveform analysis | Maintenance of SVV > 10% for > 10 min |
| 5 | Lanchon/2017 | 6% starch, 500 mL, over 10 min | 17 (33.3) | MAP increase ≥ 15% | Arterial waveform analysis | Increase in stroke volume ≥ 15% after volume expansion |
| 6 | de Courson/2019 | 0.9% Saline, 250 mL, over 10 min | 21 (37.5) | MAP increase ≥ 10% |
Oesophageal Doppler |
SVV > 10%, assessed by using oesophageal Doppler |
| 7 | Guarracino/2019 | 0.9% Saline, 30 mL/kg, within 3 h of enrolment | 35 (63.6) | MAP restored to > 65 mmHg | Arterial waveform analysis | Cardiac index increased by > 15% after fluid expansion |
| 8 | Luetrakool/2020 | Crystalloid, 500 mL, over 15 min | 9 (39.1) | MAP increase ≥ 10% | Arterial waveform analysis | Passive leg-raising test: cardiac output (CO) increase of 10% or more, or Mini-fluid challenge test: increase in velocity time integral by 10% or more after 100 mL crystalloid infusion over one minute |
No. number, MAP mean arterial pressure, NE norepinephrine, PEEP positive end-expiratory pressure, ICU intensive care unit, SVV stroke volume variation, NR no record, PICCO pulse indicator continuous cardiac output