Preemptive analgesia in rhegmatogenous retinal detachment surgery: is it effective?

Efficacy of peribulbar bupivacaine at the end of surgery in the management of postoperative pain after scleral buckling

PURPOSE

To compare the efficacy of peribulbar bupivacaine with routine analgesics for pain management in patients undergoing scleral buckling.

METHODS

In total, 72 patients undergoing scleral buckling or combined with vitrectomy were enrolled in this study. Patients were randomized into two groups, each containing 36 patients. Patients of group A received 5 mL of bupivacaine (0.5%) injection at the end of surgery, whereas group B patients received routine analgesics. The postoperative pain score was assessed in the first 24 hours of the postoperative period with the visual pain analog score.

RESULTS

Maximum postoperative pain scores were lower in patients receiving bupivacaine block (median: 3; range: 3-7) than in the control group (median: 5; range: 3-9). Pain scores in group A were lower than in the control group both at 3 and 6 hours after surgery, which was statistically significant ( P < 0.001). Four patients in group A and 17 patients in group B needed additional analgesia in the first 24 hours of the postoperative period. In addition, two patients in group A and seven patients in group B experienced episodes of nausea and vomiting in the first 24 hours of surgery.

CONCLUSION

The results of this study suggest that the postoperative experience of patients undergoing scleral buckling surgery can be made more comfortable with the use of bupivacaine block at the end of surgery.

Adverse Events during Vitrectomy under Adequacy of Anesthesia-An Additional Report

The intraprocedural immobilization of selected subsets of patients undergoing pars plana vitrectomy (PPV) requires the performance of general anesthesia (GA), which entails the intraoperative use of hypnotics and titration of opioids. The Adequacy of Anesthesia (AoA) concept of GA guidance optimizes the intraoperative dosage of hypnotics and opioids. Pre-emptive analgesia (PA) is added to GA to minimize intraoperative opioid (IO) usage. The current additional analysis evaluated the advantages of PA using either COX-3 inhibitors or regional techniques when added to AoA-guided GA on the rate of presence of postoperative nausea and vomiting (PONV), oculo-emetic (OER), and oculo-cardiac reflex (OCR) in patients undergoing PPV. A total of 176 patients undergoing PPV were randomly allocated into 5 groups: (1) Group GA, including patients who received general anesthesia alone; (2) Group T, including patients who received preventive topical analgesia by triple instillation of 2% proparacaine 15 min before induction of GA; (3) Group PBB, including patients who received PBB; (4) Group M, including patients who received PA using a single dose of 1 g of metamizole; (5) Group P, including patients who received PA using a single dose of 1 g of acetaminophen. The incidence rates of PONV, OCR, and OER were studied as a secondary outcome. Despite the group allocation, intraoperative AoA-guided GA resulted in an overall incidence of PONV in 9%, OCR in 12%, and OER in none of the patients. No statistically significant differences were found between groups regarding the incidence of OCR. PA using COX-3 inhibitors, as compared to that of the T group, resulted in less overall PONV (p < 0.05). Conclusions: PA using regional techniques in patients undergoing PPV proved to have no advantage when AoA-guided GA was utilised. We recommend using intraoperative AoA-guided GA to reduce the presence of OCR, and the addition of PA using COX-3 inhibitors to reduce the rate of PONV.

The Oculocardiac Reflex: A Review

BACKGROUND

A typical oculocardiac reflex (OCR) is a moderate trigemino-vagal bradycardia elicited by tension on an extraocular muscle (EOM) during strabismus surgery; however, many other orbital stimuli can elicit cardiac slowing including retinopathy of prematurity examination.

METHODS

World literature related to trigeminovagal and oculocardiac reflex covering over 15,000 patients including 51 randomized clinical trials and case reports are analyzed and reviewed. Under an ongoing observational trial in Alaska, anesthetic, patient and surgical influences on routine strabismus surgery using prospective, uniform EOM tension are compared seeking sufficient sample size to characterize this individually widely variable cardiac response.

RESULTS

With adequate sample size, and emphasizing clinical studies controlling type of EOM, muscle tension amount and duration, anticholinergic and opioid medications, the following augment OCR; rapid-acting opioids and dexmedetomidine while OCR is reduced in older patients, the right eye, less EOM tension, deeper inhaled agents, hypocarbia, anticholinergic medications and orbital block. In re-operations, the former are relatively poor predictors of subsequent OCR.

CONCLUSION

Profound bradycardia can occur in almost 10% of strabismus surgery cases without anticholinergic preventive measures, but reliable prediction of OCR remains elusive. With foreknowledge and careful anesthetic monitoring of the patient before EOM manipulation, residual adverse sequelae from OCR are fortunately very rare. Despite well over a century of experience, the teleology for this occasionally dramatic cardiac response to eye surgery is still not known.

Preventive Analgesia, Hemodynamic Stability, and Pain in Vitreoretinal Surgery

Background and Objectives: Although vitreoretinal surgery (VRS) is most commonly performed under regional anaesthesia (RA), in patients who might be unable to cooperate during prolonged procedures, general anaesthesia (GA) with intraprocedural use of opioid analgesics (OA) might be worth considering. It seems that the surgical pleth index (SPI) can be used to optimise the intraprocedural titration of OA, which improves haemodynamic stability. Preventive analgesia (PA) is combined with GA to minimise intraprocedural OA administration. Materials and Methods: We evaluated the benefit of PA combined with GA using SPI-guided fentanyl (FNT) administration on the incidences of PIPP (postprocedural intolerable pain perception) and haemodynamic instability in patients undergoing VRS (p < 0.05). We randomly assigned 176 patients undergoing VRS to receive GA with SPI-guided FNT administration alone (GA group) or with preventive topical 2% proparacaine (topical anaesthesia (TA) group), a preprocedural peribulbar block (PBB) using 0.5% bupivacaine with 2% lidocaine (PBB group), or a preprocedural intravenous infusion of 1.0 g of metamizole (M group) or 1.0 g of paracetamol (P group). Results: Preventive PBB reduced the intraprocedural FNT requirement without influencing periprocedural outcomes (p < 0.05). Intraprocedural SPI-guided FNT administration during GA resulted in PIPP in 13.5% of patients undergoing VRS and blunted the periprocedural effects of preventive intravenous and regional analgesia with respect to PIPP and haemodynamic instability. Conclusions: SPI-guided FNT administration during GA eliminated the benefits of preventive analgesia in the PBB, TA, M, and P groups following VRS.

Regional Anesthesia for Pediatric Ophthalmic Surgery: A Review of the Literature

Ophthalmic pediatric regional anesthesia has been widely described, but infrequently used. This review summarizes the available evidence supporting the use of conduction anesthesia in pediatric ophthalmic surgery. Key anatomic differences in axial length, intraocular pressure, and available orbital space between young children and adults impact conduct of ophthalmic regional anesthesia. The eye is near adult size at birth and completes its growth rapidly while the orbit does not. This results in significantly diminished extraocular orbital volumes for local anesthetic deposition. Needle-based blocks are categorized by relation of the needle to the extraocular muscle cone (ie, intraconal or extraconal) and in the cannula-based block, by description of the potential space deep to the Tenon capsule. In children, blocks are placed after induction of anesthesia by a pediatric anesthesiologist or ophthalmologist, via anatomic landmarks or under ultrasonography. Ocular conduction anesthesia confers several advantages for eye surgery including analgesia, akinesia, ablation of the oculocardiac reflex, and reduction of postoperative nausea and vomiting. Short (16 mm), blunt-tip needles are preferred because of altered globe-to-orbit ratios in children. Soft-tip cannulae of varying length have been demonstrated as safe in sub-Tenon blockade. Ultrasound technology facilitates direct, real-time visualization of needle position and local anesthetic spread and reduces inadvertent intraconal needle placement. The developing eye is vulnerable to thermal and mechanical insults, so ocular-rated transducers are mandated. The adjuvant hyaluronidase improves ocular akinesia, decreases local anesthetic dosage requirements, and improves initial block success; meanwhile, dexmedetomidine increases local anesthetic potency and prolongs duration of analgesia without an increase in adverse events. Intraconal blockade is a relative contraindication in neonates and infants, retinoblastoma surgery, and in the presence of posterior staphylomas and buphthalmos. Specific considerations include pertinent pediatric ophthalmologic topics, block placement in the syndromic child, and potential adverse effects associated with each technique. Recommendations based on our experience at a busy academic ophthalmologic tertiary referral center are provided.

Postoperative Analgesic Efficacy of Sub-Tenon's Block with Levobupivacaine in Retinal Surgery under General Anesthesia

Background:

Vitreoretinal surgery is associated with undesirable intraoperative and postoperative complications including pain, postoperative nausea and vomiting, and oculocardiac reflex (OCR). Systemic analgesics have side effects and are contraindicated in some cases. We hypothesized that the preoperative sub-Tenon's injection of levobupivacaine with general anesthesia would decrease postoperative pain and intraocular pressure as well as the incidence of complication.

Methods:

Eighty patients who were presented for vitreoretinal surgery, aged 30–60 years, were enrolled in the study. General anesthesia was administrated to all patients; then, they were randomized into two equal groups (40 each) – Group I: patients received 5 mL placebo solution for sub-Tenon's block and Group II: patients received 4 mL levobupivacaine 0.5% in 1 mL saline for sub-Tenon's block. Postoperative pain was evaluated using a verbal pain scale. Surgeon satisfaction, postoperative analgesic consumption, and perioperative hemodynamics were also reported.

Results:

Verbal rating pain scores were significantly lower at the first 6 h postoperative in Group II (sub-Tenon's levobupivacaine) compared to Group I (sub-Tenon's placebo). First analgesic rescue time and total dose of analgesic consumption were significantly reduced in Group II compared to Group I. There was a lower incidence of OCR with sub-Tenon's levobupivacaine (Group II), also surgeon satisfaction was significantly superior in the same group.

Conclusion:

The combination of general anesthesia with sub-Tenon's block using levobupivacaine in retinal surgery patients reduces pain scores after surgery; total analgesia requirement also decreases the incidence of OCR.

Controlled-release oxycodone is better tolerated than intravenous tramadol/metamizol for postoperative analgesia after retinal-surgery

PURPOSE

We assessed the clinical efficacy and tolerance of controlled-release oxycodone (CRO), comparing it with intravenous tramadol/metamizol combination in this prospective, randomised, double-blind study of 35 ASA physical status I-III patients undergoing retinal-surgery.

METHODS

General anaesthesia using remifentanil and propofol was performed for surgery. On arrival in the recovery room patients were randomly allocated to two groups. The controlled-release oxycodone group (CRO Group) received 10 mg CRO. 12 h after the initial dose another 10 mg CRO were administered. Simultaneously with the initial CRO dose, and every 4 h up to 24 h postoperatively, the CRO Group received intravenous isotonic saline infusion. On arrival in the recovery room the tramadol/metamizol group (TM Group) received a placebo tablet, and 12 h later a second placebo. Simultaneously 100 mg tramadol combined with 1 g metamizol were administered intravenously every 4 h until 24 h postoperatively. All patients had access to intravenous opioid rescue medication.

RESULTS

The AUC for quality of analgesia was significantly higher in the CRO Group than in the TM Group (p = 0.0023). Patient rated quality of analgesia significantly higher in the CRO Group than in the TM Group 8 h (p = 0.048), 16 h (p = 0.009) and 24 h (p = 0.001) postoperatively. There was no statistical difference in AUC for pain scores between groups (p = 0.205). The CRO Group experienced significantly less nausea than the TM Group (p = 0.012). Six patients in the TM Group in contrast to none in the CRO Group interrupted the study before finishing the study protocol (p = 0.022).

CONCLUSIONS

We conclude that CRO administered twice in the first 24 h postoperatively is superior to intravenous tramadol/metamizol for postoperative analgesia after retinal surgery, with fewer adverse events and greater patient satisfaction.

Preoperative Sub–Tenon’s Capsule Injection of Ropivacaine in Conjunction with General Anesthesia in Retinal Detachment Surgery

OBJECTIVE

To evaluate the effects of preoperative sub-Tenon's capsule injection of ropivacaine on intraoperative hemodynamics, postoperative pain, nausea, and recovery in patients undergoing scleral buckling surgery under general anesthesia (GA).

DESIGN

Randomized double-masked controlled clinical trial.

PARTICIPANTS

Ninety-eight patients with primary rhegmatogenous retinal detachment undergoing scleral buckling surgery under GA.

METHODS

Random allocation to either preoperative sub-Tenon's capsule injection of 3 ml of 0.75% ropivacaine or sub-Tenon's capsule injection of 3 ml of saline (controls) immediately before a scleral buckling procedure under GA. Intraoperative monitoring of hemodynamic parameters, need of analgesia with sevoflurane and alfentanil, time in the recovery unit, measurements of pain and nausea on the visual analog scale (VAS) up to 12 hours postoperatively, and consumption of analgesics and antiemetics was recorded.

MAIN OUTCOME MEASURES

Intraoperative systolic blood pressure (BP); bradycardia; minimum alveolar concentration (MAC) of sevoflurane; maximum postoperative VAS scores of pain and nausea; time in recovery unit; and total need of alfentanil, ketobemidone, dextropropoxyphene, and dixyrazine.

RESULTS

Ninety-seven patients were analyzed (48 in the ropivacaine group and 49 controls). A significantly lower intraoperative systolic BP (104+/-6 vs. 112+/-7 mmHg; P = 0.004), less need of sevoflurane (1.33+/-0.19 vs. 1.56+/-0.23; P = 0.03), and shorter time in the recovery unit (67+/-9 vs. 76+/-16 minutes; P = 0.01) were observed in the ropivacaine group. Maximum VAS pain scores were 50+/-21 in the control group and 36+/-25 in the ropivacaine group (P = 0.05), with a significantly lower consumption of opioids (ketobemidone) in the ropivacaine group (3.6+/-3.5 vs. 1.3+/-2.0 mg). No significant difference was observed regarding nausea or need of dixyrazine or dextropropoxyphene postoperatively.

CONCLUSIONS

Preoperative sub-Tenon's capsule injection of ropivacaine in scleral buckling surgery under GA lowers the intraoperative systolic BP, reduces the amount of inhalable sevoflurane needed, and enhances postoperative vigilance through reduction of pain and need of opioids.

Preemptive sub-Tenon's anesthesia for pars plana vitrectomy under general anesthesia: is it effective?

BACKGROUND AND OBJECTIVES

To determine whether irrigation of the sub-Tenon's space with anesthetic agents during pars plana vitrectomy (PPV) involving general anesthesia decreases postoperative pain, analgesic use, or nausea.

PATIENTS AND METHODS

A prospective, controlled trial of 46 consecutive patients requesting general anesthesia for PPV who were randomized to receive or not receive a sub-Tenon's space injection prior to surgery. A mixture of 3 mL of 2% lidocaine with hyaluronidase and 3 mL of 0.5% bupivacaine was used to induce local blockade. Pain, postoperative nausea, and analgesia use were evaluated.

RESULTS

Local blockade did not significantly alter the proportion of reported pain at 30 minutes and 2, 4, and 24 hours after the operation. The local blockade had no effect on reducing postoperative nausea or the number of patients requiring pain medication.

CONCLUSIONS

Local blockade prior to surgery in patients undergoing PPV under general anesthesia does not significantly decrease postoperative pain, analgesic use, or nausea.

A comparison between IV paracetamol and IV metamizol for postoperative analgesia after retinal surgery

OBJECTIVE

To assess clinical efficacy of IV paracetamol 1 g and IV metamizol 1 IV metamizol 1 g on a 24-h dosing schedule in this randomized, double-blinded, placebo-controlled study of 38 ASA physical status I-III patients undergoing retinal surgery.

RESEARCH DESIGN AND METHODS

General anaesthesia using remifentanil, propofol, and desflurane was performed for surgery. The patients were randomly allocated to three groups, receiving infusions of paracetamol 1 g/100 mL (Para Group), of metamizol 1 g/100 mL (Meta Group), or of 100 mL of saline solution as placebo control (Plac Group) 30 min before arrival in the recovery area and every 6 h up to 24 h postoperatively. All patients had unrestricted access to intravenous opioid rescue medication.

MAIN OUTCOME MEASURES

The primary efficacy variables were pain scores at rest over 30 h postoperatively analysed by using repeated ANOVA measurement. Secondary efficacy variables were pain scores on coughing, also analysed by repeated ANOVA measurement.

RESULTS

Five patients in the Plac Group and one patient in the Meta Group interrupted the study protocol. Regarding pain scores at rest, Mauchly-test of sphericity was significant (p = 0.03). For the p time effects a significant result was detected (p < 0.001). The main effect between the three treatment groups was significantly different (p = 0.01). The Bonferroni adjusted pair wise comparisons between p the Plac Group and the Para Group showed a significant difference in favour of IV paracetamol (p = 0.024; mean difference 14.8; p 95% CI 1.6-28.0), between the Plac Group and the Meta Group in favour of IV metamizol (p = 0.025; mean difference 14.4; 95% CI p 1.5-27.4), and no significant difference between the Para Group and the Meta Group (p = 1.0; mean difference 0.4; 95% CI-12.8 to 13.6). Pain scores on coughing showed a significant different main effect between the three treatment groups (p = 0.022). The Bonferroni adjusted pair wise comparisons between the Plac Group and the Para Group showed a significant difference in favour of IV paracetamol (p = 0.032; mean difference 17.9; 95% CI 1.3-34.6), a p difference, though not reaching statistical significance, in favour of IV metamizol between the Plac Group and the Meta Group (p = 0.081; p mean difference 15.0; 95% CI -1.4 to 31.4), and no significant difference between the Para Group and the Meta Group (p = 1.0; p mean difference 2.9; 95% CI -13.8 6 to 19.6). None of the patients experienced itching; one patient in the Meta Group developed a mild erythema. There was no statistical difference in the incidence of nausea (Plac vs. Para Group: p = 0.94, Plac vs. Meta Group: p = 0.98, Para vs Meta Group: p = 0.95) or vomiting (Plac vs. Para Group: p = 0.73, Plac vs. Meta Group: p = 0.85, Para vs Meta Group: p = 0.86) between the groups. Patients in the Plac Group experienced significantly more often sedation than patients in the Meta Group (p = 0.049). There was a trend of higher sedation in the Plac Group than in the Para Group, which did not reach statistical significance (p = 0.07). There was no difference in sedation between the Meta and the Para Groups (p = 0.84).

CONCLUSION

IV paracetamol 1 g has a similar analgesic potency as IV metamizol 1 g for postoperative analgesia after retinal surgery.

The efficacy of preemptive analgesia for acute postoperative pain management: a meta-analysis

Whether preemptive analgesic interventions are more effective than conventional regimens in managing acute postoperative pain remains controversial. We systematically searched for randomized controlled trials that specifically compared preoperative analgesic interventions with similar postoperative analgesic interventions via the same route. The retrieved reports were stratified according to five types of analgesic interventions: epidural analgesia, local anesthetic wound infiltration, systemic N-methyl-d-aspartic acid (NMDA) receptor antagonists, systemic nonsteroidal antiinflammatory drugs (NSAIDs), and systemic opioids. The primary outcome measures analyzed were the pain intensity scores, supplemental analgesic consumption, and time to first analgesic consumption. Sixty-six studies with data from 3261 patients were analyzed. Data were combined by using a fixed-effect model, and the effect size index (ES) used was the standardized mean difference. When the data from all three outcome measures were combined, the ES was most pronounced for preemptive administration of epidural analgesia (ES, 0.38; 95% confidence interval [CI], 0.28-0.47), local anesthetic wound infiltration (ES, 0.29; 95% CI, 0.17-0.40), and NSAID administration (ES, 0.39; 95% CI, 0.27-0.48). Whereas preemptive epidural analgesia resulted in consistent improvements in all three outcome variables, preemptive local anesthetic wound infiltration and NSAID administration improved analgesic consumption and time to first rescue analgesic request, but not postoperative pain scores. The least proof of efficacy was found in the case of systemic NMDA antagonist (ES, 0.09; 95% CI, -0.03 to 0.22) and opioid (ES, -0.10; 95% CI, -0.26 to 0.07) administration, and the results remain equivocal.

Sub-Tenon infiltration or classical analgesic drugs to relieve postoperative pain

BACKGROUND

In a prospective randomized double-blind study, the analgesic effect produced by sub-Tenon infiltration was compared with classic analgesic drugs in patients scheduled for posterior segment surgery under general anaesthesia.

METHODS

One hundred patients were randomized into two groups of 50. One group received sub-Tenon infiltration (group 1) with 3 mL of bupivacaine 0.50% by the surgeon before the end of the surgery and the other (group 2) received only classical analgesic drugs postoperatively. A visual analogue scale (VAS) (graded from 1 to 10) was used to assess pain. For both groups, when VAS was between 1 and 3 paracetamol (3 g/24 h) associated with ketoprofen (200 mg/24 h) was given; between 3 and 6 nalbuphine (0.2 mg/kg slowly intravenously repeated every 4 h if necessary) was given; and over 6 morphine was given. Morphine 1 mg was injected every 2 min until VAS below 3 was obtained.

RESULTS

All patients in group 2 (control) experienced pain in the recovery room period; however, no patient in group 1 required analgesic drugs in the first 6 h after the sub-Tenon infiltration. In the recovery room period, the VAS pain score in patients who received sub-Tenon infiltration (group 1) was 0.6 +/- 1.3 (mean +/- SD) compared to 3.4 +/- 2.2 in group 2. The difference was statistically significant (P = 0.000001). All patients in group 2 asked for analgesic drugs in the recovery room, some of whom required morphine. Despite the administration of drugs the pain score was statistically higher in group 2. Between the end of the recovery room period and the 6th hour, the VAS pain score in group 1 was statistically lower. From the 6th until the 24th hour, the pain score was not statistically significantly different between the groups. Regarding consumption of analgesic drugs from the recovery room until the 24th hour, the consumption of level 1 analgesic drugs (paracetamol, ketoprofen) and level 3 (morphine) was statistically lower in group 1 (P = 0.0009). The difference was not significant for level 2, probably because the number of patients was not sufficient.

CONCLUSION

Sub-Tenon infiltration with 3 mL of bupivacaine 0.50% offers excellent postoperative analgesia for about 6 h and is an excellent alternative to classical drugs. Furthermore, it is highly reliable and safe.

Oculocardiac reflex caused by contact lenses

PURPOSE

To report two cases of patients who fell unconscious because of the oculocardiac reflex when attempting to wear contact lenses.

CASE REPORTS

Case 1: A 15-year-old healthy boy came to our clinic to be fitted with contact lenses. As soon as a hard contact lens was inserted forcibly, he became unconscious. Case 2: A 22-year-old man fell unconscious the instant that the eye was compressed with a hard contact lens. Neither patient had used glasses or contact lenses before. Their blood pressure was decreased while unconscious. They recovered consciousness after about 10 min, and nausea and vomiting settled subsequently. Contact lens insertion was tried again carefully after 1 week avoiding compression of the eyes and there were no problems. They are currently using contact lenses without any problems.

CONCLUSION

Insertion of contact lenses may rarely provoke the oculocardiac reflex.