Complications | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | Participants (studies) (n) | Certainty of the evidence (GRADE) | |
Risk with no PNB | Risk with PNB | ||||
Mortality | 1 per 1000 |
1 per 1000
(1 to 1) |
OR 1.07
(0.92 to 1.24) | 932 102 (5 RCTs, 5 observational studies) | ⨁⨁◯◯ low |
Cardiac without MI | 23 per 1000 |
19 per 1000
(19 to 20) |
OR 0.83
(0.79 to 0.86) | 720 282 (7 RCTs, 4 observational studies) | ⨁⨁⨁◯ moderate† |
MI | 10 per 1000 |
6 per 1000
(2 to 18) |
OR 0.57
(0.18 to 1.78) | 1360 (7 RCTs, 1 observational study) | ⨁⨁⨁◯ moderate† |
Pulmonary | 12 per 1000 |
10 per 1000
(9 to 10) |
OR 0.84
(0.79 to 0.89) | 721 469 (16 RCTs, 5 observational studies) | ⨁⨁⨁◯ moderate† |
Respiratory failure | 41 per 1000 |
16 per 1000
(8 to 31) |
OR 0.37
(0.18 to 0.75) | 1246 (9 RCTs, 4 observational studies) | ⨁⨁⨁⨁ high† |
Pneumonia | 22 per 1000 |
26 per 1000
(11 to 60) |
OR 1.15
(0.47 to 2.80) | 705 (6 RCTs) | ⨁⨁⨁◯ moderate† |
Gastrointestinal | 4 per 1000 |
3 per 1000
(3 to 4) |
OR 0.93
(0.83 to 1.04) | 720 230 (7 RCTs, 2 observational studies) | ⨁⨁⨁◯ moderate† |
Renal | 15 per 1000 |
14 per 1000
(13 to 15) |
OR 0.96
(0.91 to 1.02) | 720 111 (3 RCTs, 3 observational studies) | ⨁⨁◯◯ low |
Renal failure | 26 per 1000 |
21 per 1000
(8 to 52) |
OR 0.82
(0.32 to 2.04) | 685 (3 RCTs, 2 observational studies) | ⨁⨁⨁◯ moderate† |
Cognitive dysfunction | 130 per 1000 |
72 per 1000
(48 to 107) |
OR 0.52
(0.34 to 0.80) | 1563 (8 RCTs, 4 observational studies) | ⨁⨁⨁⨁ high |
Delirium | 143 per 1000 |
69 per 1000
(36 to 128) |
OR 0.44
(0.22 to 0.88) | 899 (3 RCTs, 2 observational studies) | ⨁⨁⨁⨁ high |
Stroke | 1 per 1000 |
1 per 1000
(1 to 1) |
OR 0.95
(0.76 to 1.18) | 719 734 (3 RCTs, 1 observational study) | ⨁⨁◯◯ low† |
Surgical site infection | 10 per 1000 |
9 per 1000
(8 to 9) |
OR 0.86
(0.80 to 0.91) | 796 090 (18 RCTs, 7 observational studies) | ⨁⨁◯◯ low |
Any infection | 21 per 1000 |
16 per 1000
(16 to 17) |
OR 0.77
(0.73 to 0.80) | 789 622 (8 RCT, 3 observational studies) | ⨁⨁◯◯ low |
Sepsis | 5 per 1000 |
6 per 1000
(1 to 32) |
OR 1.37
(0.27 to 7.05) | 433 (2 RCTs, 1 observational study) | ⨁⨁◯◯ low*‡ |
Thromboembolism | 11 per 1000 |
10 per 1000
(9 to 10) |
OR 0.90
(0.84 to 0.96) | 790 835 (17 RCTs, 6 observational studies) | ⨁⨁◯◯ low |
Perioperative nerve injury | 6 per 1000 |
7 per 1000
(4 to 11) | OR 1.02 (0.59 to 1.76) | 8590 (1 observational study) | ⨁⨁◯◯ low |
Blood transfusion | 165 per 1000 |
152 per 1000
(151 to 154) |
OR 0.91
(0.90 to 0.92) | 1 250 014 (3 RCTs, 3 observational studies) | ⨁⨁⨁◯ moderate† |
Blood loss | MD 42.53 lower
(52.08 lower to 32.98 lower) | – | 890 (8 RCTs, 2 observational studies) | ⨁⨁⨁⨁ high | |
Critical care admission | 67 per 1000 |
72 per 1000
(70 to 74) |
OR 1.07
(1.04 to 1.10) | 719 767 (2 RCTs, 2 observational studies) | ⨁⨁◯◯ low |
Readmission | 52 per 1000 |
35 per 1000
(32 to 37) |
OR 0.66
(0.61 to 0.70) | 146 453 (3 observational studies) | ⨁⨁◯◯ low |
Length of stay | MD 0.02 higher
(0.01 lower to 0.04 higher) | – | 86 770 (37 RCTs, 21 observational studies) | ⨁⨁◯◯ low†‡ |
GRADE Working Group grades of evidence.
High certainty: we are very confident that the true effect lies close to that of the estimate of the effect.
Moderate certainty: we are moderately confident in the effect estimate: the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low certainty: our confidence in the effect estimate is limited: the true effect may be substantially different from the estimate of the effect.
Very low certainty: we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect.
*The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
† Optimal Information Size (OIS) low.
‡Heterogeneity detected.
GRADE, Grading of Recommendations Assessment, Development, and Evaluation; MD, mean difference; MI, myocardial infarction; PNB, peripheral nerve block; RCT, randomized controlled trial.