Table 5 Comments related to clinical importance

Thoracic paravertebral block to provide analgesia in breast surgery

With the rating scale from 0 to 10.0, the maximal decrease in pain intensity of 0.89 (1.29; 0.49)--determined in the related meta-analysis-- was less than the minimal clinically important improvement with pain of moderate intensity: ≥ 1.9 [10]. The comment of authors of the meta-analysis – “Thoracic paravertebral block has a limited beneficial effect on quality of recovery”-- confirms that the proof of meaningful clinical improvement due to this intervention was not convincing.

Perineural dexamethasone as an analgesic adjunct for peripheral nerve block

The perineural administration of dexamethasone seems to provide only modest and inconsistent addition to its systemic effect on the duration of postoperative analgesia [28, 29]. Thus the observed effect is mostly due to the systemic analgesic effect of dexamethasone described long ago. The authors of the meta-analysis made a similar comment in this regard.

Transversus abdominis plane block to provide analgesia in abdominal surgery

The block-induced reduction in postoperative morphine consumption was so modest that the authors of the meta-analysis made the following comments on the clinical importance of the outcome: “Marginal analgesic efficacy”... “Clinical impact is questionable”. A problem could be seen in the very high heterogeneity of the related analysis (I² = 94%), probably due to inclusion in the analysis of very different types of surgical procedures and many other outcome variables. In addition, there was no appropriate comparison to other well-established analgesic regimens [32].

Ultrasound guidance for peripheral nerve blocks

The absence of major problems with the meaningful clinical improvement resulting from this technique is reassuring. In addition, the related meta-analysis has an exceptionally low degree of heterogeneity (I² = 16%).

Femoral nerve block to provide analgesia in knee surgery

With the rating scale from 0 to 10.0, the maximal decrease in postoperative pain intensity of 0.72 (0.93; 0.51) determined in the related meta-analysis was less than the minimal clinically important improvement with pain of moderate intensity ≥ 1.9 [10]. In addition, the improvement was observed only when compared with IV PCA, not with the other common methods of analgesia (epidural or local infiltration).

Effect of perioperative epidural analgesia combined with general analgesia on mortality in cardiac surgery

The statistical power was too low to reach even statistical significance for beneficial effect estimate.

Preemptive effect of epidural analgesics

The authors of the related meta-analysis expressed the effect on pain only as a value that has no units, therefore the real pain score change is difficult to assess. However, the effect size of the observed difference was graded as medium, not large (Table 4). Continuing controversy regarding degree of clinical effectiveness of preemptive anesthesia makes it difficult to come to definite conclusion on the clinical importance related to this intervention.

Spinal anesthesia is associated with lower intraoperative blood loss

The assessment of the clinical importance of this meta-analysis result is weakened by the absence of data on the risk of bias, heterogeneity, and the inclusion of very old RCTs starting in 1972. The meaningful clinical importance was not quite obvious to the authors of this meta-analysis, who commented: “Unclear that this finding is clinically meaningful, e.g. with result in a reduction of blood transfusion.”