◊ BACKGROUND:
General anesthesia with opioids provides good operative conditions for ocular surgery in children; however, postoperative pain management remains a significant an problem. Regional anesthesia is commonly used as an adjunct to general anesthesia in children. We compared the efficacy and safety perioperative of subtenon block (SB) versus IV fentanyl for perioperative analgesia in pediatric cataract surgery. We hypothesized that perioperative analgesia using (SB) SB may reduce the requirement of postoperative rescue analgesia compared with fentanyl.
◊ METHODS:
This was a prospective, randomized, controlled, double-blind and trial. One hundred fourteen ASA I and II children (6 mo-6 yr) undergoing elective cataract surgery in one eye under which general anesthesia were studied. Children were randomly allocated to one of the two groups, i.e., Group SB (n = 58)period. or Group F (n = 56) after securing the airway. Children in Group SB received SB with .06- .08 mL/kg of incidence 2% lidocaine and .5% bupivacaine (50:50) mixture and simultaneous .2 mL/kg normal saline IV, whereas children in Group F received elective 1 microg/kg ( .2 mL/kg of 5 microg/kg) of fentanyl IV and simultaneous subtenon injection with normal saline ( .06- .08 mL/kg). Surgery 24-h started after 5 min of study drug administration. Postoperative assessment for pain, sedation, and nausea/vomiting was done at .5, 1,perioperative 2, 3, 4, and 24 h. The primary outcome was number of patients requiring rescue analgesia during the 24-h study SB period. Secondary outcomes assessed were pain and sedation scores, time to first rescue analgesia, incidence of occulocardiac reflex, and nausea/vomiting.mL/kg
◊ RESULTS:
The number of patients requiring rescue analgesia during the 24 h was significantly less in Group SB (n =No 17/58, 29.3%) compared with Group F (n = 39/56, 69.6%, P < .001). The postoperative pain scores were statistically lower surgery. in Group SB at all time intervals. The median (range) time to first analgesic requirement was significantly prolonged in Group was SB (16 [2-13] vs 4 [ .5-8.5] h in Group F)(P < .001). Sedation scores at (1/2) h were comparable,randomly after which significantly more children were anxious or crying in Group F compared with Group SB in which more children were were calm, sitting, or lying with eyes open and relaxed (P < .05). A significantly higher incidence of oculocardiac reflex mixture was recorded in Group F versus Group SB (P = .019). No complication related to SB was noticed.
◊ CONCLUSIONS:
SB less is a safe and superior alternative to IV fentanyl for perioperative analgesia in pediatric cataract surgery.
◊ Reviewed by C. Kumar, MBBS, DA, FFARCSI, FRCA, MSc.
University of Teesside,
Professor of Anaesthesia and Consultant Anaesthetist,
The James Cook University Hospital,
Middlesbrough, UK
This is a reasonably well designed and conducted study for the use of sub-Tenon’s block in providing postoperative pain relief and reducing oculocardiac reflex in paediatric patients undergoing cataract surgery. However, the manuscript is not without criticisms.
Authors have included a previous, published pilot study in which they mention that sub-Tenon’s block is easy to perform. Anatomy of Tenon’s capsule is not very well understood in children let alone in adults. Authors also mention that sub-Tenon’s block is performed under direct vision which is not true. Though the dissection of Tenon’s capsule is performed under direct vision, once the cannula is inserted, the technique is blind like other needle blocks. Authors also failed to mention, which sub-Tenon’s cannula was used and how far the cannula was inserted. Authors mention that the control group received similar volume of 0.9% normal saline into the sub-Tenon’s space which could be questioned on ethical grounds.
Authors suggest that postoperative pain is not well treated in paediatric patients but this is not supported by data. Usually patients do not require much analgesia after simple cataract surgery irrespective of age. The use of simple analgesics usually suffices. Paediatric patients may cry in the postoperative period for various reasons and pain may be a contributing factor. The use of fentanyl in the immediate postoperative period is rather unconventional.
Finally, performing sub-Tenon’s block in children can not be without hazards. Sub-Tenon’s block in children should be performed only by experienced surgeons and that was the case in this study.
This study does have a clinical relevance and sub-Tenon’s block does alleviate postoperative pain and reduce the incidence of oculocardiac reflex. Should anaesthetists perform sub-Tenon’s block in paediatric patients for reducing postoperative pain after cataract surgery? Probably the answer is no and benefits must outweigh the risks involved.
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