Table 4 Secondary Endpoints.

From: Open-lung strategies and mechanical power during protective ventilation for laparoscopic anterior resection: a randomised controlled trial

 

PARM

(n = 25)

PEEP

(n = 25)

Combination

(n = 25)

P value

Intraoperative endpoints

P/F ratio at T3 (mmHg)

348 ± 77*#

424 ± 78

446 ± 121

0.001

P/F ratio difference (T1-T3)

17.0 ± 83.9

25.0 ± 63.8

10.0 ± 89.4

0.802

P/F ratio reduction (T3/T1 < 1)

11 (44.0)

16 (64.0)

15 (60.0)

0.430

Hypoxemiaa

0 (0.0)

0 (0.0)

0 (0.0)

NA

Shunt fractionb at T3 (%)

6.24 ± 2.80

5.82 ± 1.75

5.35 ± 2.37

0.415

Dead spacec at T3 (%)

22.0 ± 7.0

20.2 ± 9.1

17.9 ± 6.5

0.170

Hypotensiond

1 (4.0)

3 (12.0)

1 (4.0)

0.609

Bradycardiae

1 (4.0)

0 (0.0)

2 (8.0)

0.769

Need for vasopressorsf

3 (12.0)

5 (20.0)

4 (16.0)

0.923

Postoperative endpoints

Respiratory failureg at PACU

5 (20.0)

5 (20.0)

3 (12.0)

0.799

Respiratory failure within 3 days

1 (4.0)

0 (0.0)

2 (8.0)

0.769

Sustained hypoxemiah within 3 days

2 (8.0)

0 (0.0)

1 (4.0)

0.769

PPCs gradei ≥ 2 within 3 days

2 (8.0)

1 (4.0)

2 (8.0)

1.000

Pneumothorax

0 (0.0)

0 (0.0)

1 (4.0)

1.000

Pleural effusion

2 (8.0)

3 (12.0)

2 (8.0)

1.000

Admission to ICU within 30 days

1 (4.0)

0 (0.0)

0 (0.0)

1.000

Extrapulmonary complicationsj

7 (28.0)

2 (8.0)

3 (12.0)

0.208

Death within 30 days

0 (0.0)

0 (0.0)

0 (0.0)

NA

Postoperative hospital stays (days)

8 [6 to 12.5]

7 [6 to 8]

7 [5.5 to 8.5]

0.264

  1. Values are the frequencies (percentage), mean ± standard deviation or median [interquartile].
  2. * P < 0.05 compared with PEEP group. # P < 0.05 compared with combination group. NA, no analysis; PARM, periodic alveolar recruitment manoeuvre; PEEP, positive end-expiratory pressure; T1, 5 to 15 min after tracheal intubation (at least 5 min after the first ARM) and before the insufflation of pneumoperitoneum; T2, 0.5 h after pneumoperitoneum; T3, the end of surgery, when pneumoperitoneum was stopped for at least 5 min, and the patient was in supine position without spontaneous breathing; P/F, arterial partial pressure of oxygen: fraction of inspired oxygen (PaO2/FiO2); PACU, post-anaesthesia care unit; PPCs, postoperative pulmonary complications; ICU, intensive care unit.
  3. a Pulse oxygen saturation ≤ 92% lasting more than 3 min.
  4. bShunt fraction = (CcO2CaO2)/(CcO2−CvO2)×100%. Arterial oxygen content (CaO2) = (Hb × 1.31 × SaO2) + (PaO2 × 0.003); mixed venous blood oxygen content (CvO2) = (Hb × 1.31 × SvO2) + (PvO2 × 0.003); pulmonary capillary blood oxygen content (CcO2) = (Hb × 1.31 × SaO2) + (713-PaCO2/0.8) × 0.003. Hb, hemoglobin; SaO2, arterial saturation of oxygen; SvO2, venous saturation of oxygen; PvO2, venous partial pressure of oxygen; PaCO2, arterial partial pressure of carbon dioxide.
  5. c Dead space = (PaCO2−PETCO2)/PaCO2. PETCO2, partial pressure of end-tidal carbon dioxide.
  6. d Mean arterial pressure (MAP) < 60 mmHg lasting more than 3 min, or MAP ≤ 55 mmHg lasting more than one minute.
  7. e Heart rate (HR) ≤ 50 bpm and the decrease of HR from the basic value ≥ 20% lasting more than 3 min, or HR ≤ 40 bpm.
  8. f MAP < 60 mmHg and vasopressors used.
  9. g PaO2 < 60 mmHg or SpO2 < 90% on room air, or a P/F ratio < 300 mmHg and requiring oxygen therapy.
  10. h Hypoxemia (SpO2 ≤ 92% or the change of SpO2 [ΔSpO2, preoperative SpO2-postoperative SpO2] ≥ 5% when the patient was awake and breathing room air) at any two consecutive postoperative days.
  11. i Scored using a grade scale ranging from 0 to 4, with grade 0 representing the absence of any pulmonary complication and grades 1 through 4 representing successively the worse forms of complications.
  12. j Including anastomotic fistula, anastomotic stenosis, intra-abdominal infection, ileus, incision infection, chylous fistula, postoperative hemorrhage.
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