What do systematic reviews say?

Multiple vs double‐injection technique

Multiple showed no clear difference in complete failure of block1 compared with double‐injection technique (low certainty).

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  RR 0.24 [0.04, 1.41]
  9 studies · 630 participants
  Low

Double vs single‐injection technique

Double showed no clear difference in secondary analgesia failure ‐ intraoperative sedation required compared with single‐injection technique (moderate certainty).

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  RR 0.64 [0.31, 1.31]
  2 studies · 129 participants
  Moderate

Multiple vs double‐injection technique

Multiple showed no clear difference in intravascular injection compared with double‐injection technique (moderate certainty).

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  RR 0.69 [0.32, 1.49]
  7 studies · 676 participants
  Moderate

Multiple vs double‐injection technique

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  no estimate extracted
  6 studies · 510 participants
  Low

Double vs single‐injection technique

Double showed no clear difference in secondary analgesia failure ‐ tourniquet pain compared with single‐injection technique (moderate certainty).

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  RR 0.58 [0.22, 1.52]
  2 studies · 104 participants
  Moderate

Double vs single‐injection technique

Double showed no clear difference in complete failure of block3 compared with single‐injection technique (low certainty).

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  RR 1.29 [0.33, 5.01]
  7 studies · 368 participants
  Low

Double vs single‐injection technique

Double showed no clear difference in intravascular injection compared with single‐injection technique (low certainty).

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  RR 4.15 [0.46, 37.13]
  2 studies · 90 participants
  Low

Double vs single‐injection technique

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  no estimate extracted
  2 studies · 119 participants
  Low

Multiple vs single‐injection technique

Multiple leads to lower primary anaesthesia failure compared with single‐injection technique (high certainty).

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  RR 0.25 [0.14, 0.42]
  9 studies · 712 participants
  High

Multiple vs single‐injection technique

Multiple showed no clear difference in secondary analgesia failure ‐ intraoperative sedation required compared with single‐injection technique (high certainty).

• Single, double or multiple‐injection techniques for non‐ultrasound guided axillary brachial plexus block in adults… 2016 · Cochrane Headline outcomes only
  RR 0.7 [0.41, 1.19]
  5 studies · 482 participants
  High

Epidural pain relief vs systemic opioid‐based pain relief

Epidural pain relief showed no clear difference in mortality in hospital or up to 30 days compared with systemic opioid‐based pain relief (low certainty).

• Epidural pain relief versus systemic opioid‐based pain relief for abdominal aortic surgery 2016 · Cochrane Headline outcomes only
  RR 1.06 [0.6, 1.86]
  14 studies · 1383 participants
  Low

Epidural pain relief vs systemic opioid‐based pain relief

Epidural pain relief probably leads to lower myocardial infarction compared with systemic opioid‐based pain relief (moderate certainty).

• Epidural pain relief versus systemic opioid‐based pain relief for abdominal aortic surgery 2016 · Cochrane Headline outcomes only
  RR 0.54 [0.3, 0.97]
  7 studies · 851 participants
  Moderate

Epidural pain relief vs systemic opioid‐based pain relief

• Epidural pain relief versus systemic opioid‐based pain relief for abdominal aortic surgery 2016 · Cochrane Headline outcomes only
  no estimate extracted
  8 studies · 975 participants
  Low

Epidural pain relief vs systemic opioid‐based pain relief

Epidural pain relief probably leads to lower respiratory failure compared with systemic opioid‐based pain relief (moderate certainty).

• Epidural pain relief versus systemic opioid‐based pain relief for abdominal aortic surgery 2016 · Cochrane Headline outcomes only
  RR 0.69 [0.56, 0.85]
  6 studies · 861 participants
  Moderate

Epidural pain relief vs systemic opioid‐based pain relief

Epidural pain relief leads to lower gastrointestinal bleeding compared with systemic opioid‐based pain relief (high certainty).

• Epidural pain relief versus systemic opioid‐based pain relief for abdominal aortic surgery 2016 · Cochrane Headline outcomes only
  OR 0.2 [0.06, 0.65]
  4 studies · 487 participants
  High

Epidural pain relief vs systemic opioid‐based pain relief

• Epidural pain relief versus systemic opioid‐based pain relief for abdominal aortic surgery 2016 · Cochrane Headline outcomes only
  no estimate extracted
  3 studies · 162 participants
  High

Epidural pain relief vs systemic opioid‐based pain relief

• Epidural pain relief versus systemic opioid‐based pain relief for abdominal aortic surgery 2016 · Cochrane Headline outcomes only
  no estimate extracted
  3 studies · 523 participants
  Moderate

Intervention not reported

• Antifibrinolytic agents for reducing blood loss in scoliosis surgery in children 2016 · Cochrane Headline outcomes only
  no estimate extracted
  5 studies · 207 participants
  Low

Intervention not reported

It is very uncertain whether the intervention changes number of participants receiving transfusion with allogeneic blood:… (very low certainty).

• Antifibrinolytic agents for reducing blood loss in scoliosis surgery in children 2016 · Cochrane Headline outcomes only
  RR 0.11 [0.01, 1.73]
  2 studies · 79 participants
  Very low

Intervention not reported

• Antifibrinolytic agents for reducing blood loss in scoliosis surgery in children 2016 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 36 participants
  Very low