Preliminary experience of combined peri- and retrobulbar block in surgery for penetrating eye injuries.

BACKGROUND AND OBJECTIVE: Regional anaesthesia has not been recommended as an anaesthetic method for penetrating eye injuries because it is suspected to aggravate the injury already present. After having successfully managed the treatment of a penetrating eye injury under combined peri- and retrobulbar block in an ASA IV patient, it was decided to evaluate this anaesthetic method further in the treatment of such emergency cases. METHODS: Twenty adult patients with penetrating eye injuries with a maximum wound length of 8 mm extending up to 4 mm posteriorly from the limbus were operated on under combined peri- and retrobulbar anaesthesia. Eighteen patients receiving general anaesthesia served as controls. RESULTS: The mean (range) volume injected for a satisfactory peribulbar retrobulbar block was 7.4 (6.5-8.0) mL, six patients needed an additional retrobulbar injection before surgery (2.9, range 2-4, mL). All patients receiving regional anaesthesia were satisfied with the anaesthetic method and the surgeons considered the surgical conditions as good. No problems relating to local anaesthesia were observed or reported by any of the patients. CONCLUSIONS: In the hands of an experienced anaesthesiologist and under certain conditions, regional anaesthesia appears to be suitable for adult patients having penetrating eye injuries.

Topical anesthesia with or without propofol sedation versus retrobulbar/peribulbar anesthesia for cataract extraction: prospective randomized trial.

PURPOSE: To evaluate the feasibility of intravenous sedation in addition to topical anesthesia during cataract extraction. SETTING: Helsinki University Eye Hospital, Helsinki, Finland. METHODS: Three hundred seventeen eyes of 291 consecutive patients having cataract surgery were prospectively randomized to receive topical (oxybuprocaine 0.4%, n = 96), combined (topical anesthesia and propofol sedation, n = 107), or retrobulbar/peribulbar (prilocaine 1.5%, n = 114) anesthesia. The intraoperative conditions were judged by the surgeon. A numerical scale (0 to 10) was used to assess the degree of pain during surgery. Outcome measures were the number of complications and adverse events registered perioperatively and 1 week postoperatively as well as Snellen visual acuity. RESULTS: The success of posterior chamber intraocular lens (IOL) implantation through a self-sealing clear corneal incision was 97.9%, 96.3%, and 98.2% in the topical, combined, and retrobulbar/peribulbar groups, respectively. There was no difference among the groups in pain during surgery, frequency of complications, or outcome measures. One week postoperatively, visual acuity was 20/40 or better in 81.7%, 78.5%, and 77.5% of eyes in the topical, combined, and retrobulbar/peribulbar groups, respectively. The surgeon reported significantly fewer difficulties in the retrobulbar/peribulbar group (9.8%) than in the topical (26.0%) (P =.004) or combined (21.0%) (P =.036) groups. Additional sedative/analgesic medication given intraoperatively was required significantly more often in the topical (15.6%) than in the retrobulbar/peribulbar group (2.6%) (P =.002). Patients with bilateral surgery preferred combined anesthesia over retrobulbar/peribulbar anesthesia; however, there was no significant difference in patient acceptance among groups in patients having unilateral surgery. CONCLUSION: Intravenous propofol sedation added to topical anesthesia did not improve the operative conditions or surgical outcome. Retrobulbar/peribulbar anesthesia ensured the best surgical conditions. Patients in all anesthesia groups reported high satisfaction. However, patients having bilateral surgery seemed to prefer combined anesthesia over retrobulbar/peribulbar anesthesia.

Haemorrhage and risk factors associated with retrobulbar/peribulbar block: a prospective study in 1383 patients.

Patients undergoing intraocular surgery are elderly and may have disease or be receiving medication which increases the risk of haemorrhage. We interviewed 1383 consecutive patients scheduled for eye surgery requiring retrobulbar/peribulbar block about their use of non-steroidal anti-inflammatory drugs, oral steroids and warfarin. A history of diabetes mellitus and globe axial length was noted. Medial peribulbar and inferolateral retrobulbar blocks were performed by three specialists and six doctors in training. The ensuing haemorrhages were graded as follows: 1 = spot ecchymosis; 2 = lid ecchymosis involving half of the lid surface area or less; 3 = lid ecchymosis all around the eye, no increase in intraocular pressure; 4 = retrobulbar haemorrhage with increased intraocular pressure. Acetylsalicylic acid was taken by 482 (35%) patients, non-steroidal anti-inflammatory drugs by 260 (19%) and warfarin by 76 (5.5%). Lid haemorrhages (grades 1-3) were observed in 55 patients (4.0%); in 33 of these patients the haemorrhages were spotlike (grade 1). No grade 4 haemorrhages occurred. The preoperative use of acetylsalicylic acid, non-steroidal anti-inflammatory drugs or warfarin, whether or not they had been discontinued, did not predispose to haemorrhage associated with retrobulbar/peribulbar block.

Hyaluronidase as an adjuvant in bupivacaine-lidocaine mixture for retrobulbar/peribulbar block.

UNLABELLED: Hyaluronidase 7.5 IU/mL added to the local anesthetic improves peribulbar block, but smaller concentrations have not been shown to be effective. In this prospective, double-blinded study, 714 consecutive ocular surgery patients were randomized into three groups: no hyaluronidase (n = 241), hyaluronidase 3.75 IU/mL (n = 244), and hyaluronidase 7.5 IU/mL (n = 229). Retrobulbar/peribulbar block was performed with two injections of a 1:1 mixture of bupivacaine 0.75% and lidocaine 2%, 6-8 mL. Patient data were collected on demographics, initial volume of local anesthetic, need for supplementary block, and akinesia of the anesthetized eye. When hyaluronidase was used (3.75 or 7.5 IU/mL), the initial block was sufficient and the anesthetized eye was akinetic significantly more often than in the group without hyaluronidase. The hyaluronidase groups (3.75 and 7.5 IU/mL) did not differ significantly in any respect. We conclude that the addition of hyaluronidase 3.75 or 7.5 IU/mL improved the success of the initial retrobulbar/peribulbar block and akinesia and reduced the need for supplementary block. IMPLICATIONS: We conclude that the addition of hyaluronidase 3.75 or 7.5 IU/mL improved the success of the initial retrobulbar/peribulbar block and akinesia and reduced the need for supplementary block.

Stereoselective pharmacokinetics of ketorolac in children, adolescents and adults.

BACKGROUND: Previous pharmacokinetic studies on racemic ketorolac using nonstereoselective analytical methods have indicated that the plasma clearance of ketorolac is higher and the volume of distribution greater in children than in adults. The aim of this study was to study the stereoselective pharmacokinetics of racemic ketorolac in children, adolescents and adults. METHODS: 18 children (6-11 yrs), 18 adolescents (12-17 yrs) and 18 adults (18-44 yrs) participated in the study. At the end of eye surgery they were given intravenous racemic ketorolac tromethamine 0.5 mg/kg. Plasma samples were assayed for (R)- and (S)-ketorolac with high-pressure liquid chromatography. Clearance (CL), volume of distribution at steady state (Vss) and elimination (Vz) and elimination half-life (t1/2,z) were calculated with standard methods. Incidence of side-effects were recorded. RESULTS: CL, Vss, Vz and t1/2,z were higher (P<0.05) for (S)-ketorolac than for the (R)-enantiomer. Vss of the active (S)-enantiomer was higher in children than in adolescents (P<0.05) and adults (P<0.001) but the values for CL were similar. Due to the higher volume of distribution, t1/2,z was also higher in children than in adults. The pharmacokinetics of the (R)-enantiomer were essentially unaffected by age. CONCLUSION: On a pharmacokinetic basis, the maintenance dose requirements of ketorolac are similar in children, adolescents and adults.

Retrobulbar/peribulbar block with 0.2% ropivacaine or 1% lidocaine for transscleral cyclophotocoagulation or retinal panphotocoagulation.

BACKGROUND AND OBJECTIVES: Brief analgesia is needed to complete krypton laser cyclophotocoagulation for glaucoma patients and is advantageous in argon laser panphotocoagulation for diabetic retinopathy. We studied whether 0.2% ropivacaine, known for analgesia with minimal motor block or 1% lidocaine, with rapid onset and short duration of action, both supplemented with hyaluronidase, are suitable local anesthetics for retrobulbar/peribulbar block for these procedures. METHODS: Seventy-four treatment sessions of 65 patients were included in this prospective, randomized, double-blind study. Data were collected on adequacy of analgesia, need for supplementary blocks and eye movements at 10 minutes after injecting the block and at the end of the treatment, and need for patching the eye at discharge. RESULTS: Frequency of inadequate analgesia (24% in ropivacaine group and 32% in lidocaine group), and of supplementary blocks (11% and 14%, respectively) did not differ between the groups and exceeded our clinically acceptable level. Ropivacaine produced less motor block than lidocaine at 10 minutes (P < .001) and at the end of the treatment (P = .002). However, at discharge, the eye was significantly more often patched in the ropivacaine (70%) group than in the lidocaine group (41 %) (P = .035). In the ropivacaine group, a mobile eye did not predict inadequate intraoperative analgesia, whereas in the lidocaine group it did (P = .001). CONCLUSION: According to our preliminary data, neither 0.2% ropivacaine nor 1% lidocaine reached acceptable frequencies of adequate analgesia during transscleral cyclophotocoagulation, while all retinal panphotocoagulations could be completed under the initial block.

Converting to topical anesthesia in cataract surgery.

PURPOSE: To evaluate the complications and difficulties encountered by surgeons converting from paraocular to topical anesthesia in cataract surgery and to evaluate patient pain and satisfaction with each procedure. SETTING: Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. METHODS: Three hundred eyes of 245 consecutive patients were prospectively assigned by permuted block-restricted randomization to receive topical (bupivacaine 0.75%) (Group 1; n = 136) or paraocular (Group 2; n = 163) anesthesia. The intraoperative conditions were judged by the surgeon. A numerical scale (0 to 10) was used to assess the degree of pain during administration of anesthesia, during surgery, and 1 and 24 hours postoperatively. Outcome measures were the number of complications and adverse events registered perioperatively and 4 months postoperatively as well as Snellen visual acuity and surgically induced astigmatism (SIA) measured 1 week and 4 months after surgery. RESULTS: The success of posterior chamber intraocular lens (IOL) implantation through a self-sealing clear corneal incision was very high (99.3% and 96.9% in Groups 1 and 2, respectively). One case (0.7%) in the topical group required vitrectomy and implantation of an anterior chamber IOL. Anesthesia-related difficulties were reported in about 40% of patients in Group 1 and 4% in Group 2 (P < .001). Supplemental paraocular anesthesia was required in 4 cases (2.9%) in the topical group. Sedative/analgesic medication given perioperatively was required significantly more often in Group 1 (13.2%) than in Group 2 (2.4%) (P < .01). Significantly more pain during surgery (P < .001) and 1 hour after surgery (P < .001) was reported in the topical group. In Group 1 69.9% and in Group 2 93.3% reported no pain during surgery (P < .001). Chemosis (1.8%), subconjunctival hemorrhage (1.2%), and periorbital hematoma (1.2%) were seen only in the paraocular group. Perioperatively, no severe complications occurred in Group 1 and the number of adverse events was less than in Group 2. Postoperatively, 2 cases of endophthalmitis developed in the topical group and none in the paraocular group. There was no between-group difference in outcome measures; a visual acuity of 20/40 or better was found in 87.8% of eyes in Group 1 and 84.9% in Group 2 4 months postoperatively, and the percentages of eyes with SIAs within 1.0 diopter of preoperative values were similar (78.6% and 73.3%, respectively). Patient preference for topical anesthesia appeared to be higher than for paraocular anesthesia. CONCLUSION: Paraocular anesthesia gave better analgesia than topical, but topical anesthesia provided acceptable analgesia during surgery and showed that intraocular procedures can be performed without akinesia. The surgeon converting to topical anesthesia may expect slight difficulty in 40% of cases and more severe difficulty in 7%. Surgically related complications were similar with both methods.

Does propofol reduce vomiting after strabismus surgery in children?

BACKGROUND: Previous studies have indicated that propofol anaesthesia may reduce the incidence of postoperative nausea and vomiting after strabismus surgery in children. This study was designed to investigate the incidence of vomiting after strabismus surgery at two different levels of propofol anaesthesia compared to thiopental/isoflurane anaesthesia. METHODS: Ninety ASA class I or II children, aged 5-14 yrs were randomly assigned to one of three groups: Group T/I (n = 30) induction with 5 mg kg-1 of thiopental and maintenance with isoflurane, group P5 (n = 31) induction with propofol 2 mg kg-1, maintenance with propofol infusion 5 mg kg-1 h-1 or group P10 (n = 29) induction with propofol 2 mg kg-1, maintenance with propofol 10 mg kg-1 h-1. All received glycopyrrolate, vecuronium, fentanyl and controlled ventilation with O2/N2O 30/70. Ketorolac i.v. was given to prevent postoperative pain. If additional analgesia was needed, ibuprofen/acetaminophen or buprenorphine was given according to clinical need. RESULTS: There were no differences between study groups with respect to age, weight, history of previous anaesthesia or emesis after previous anaesthesia, duration of anaesthesia, surgery or sleep after anaesthesia, or number of muscles operated. The incidence of vomiting was 37%, 29% and 28% in groups T/I, P5 and P10, respectively. There were no statistically significant differences between the three groups in the incidence of vomiting. The median age of patients who vomited was 7.5 (range 5.0-13.7) yrs while the median age of the patients who did not vomit was 9.1 (range 5.0-14.0) yrs (P < 0.01). CONCLUSION: In the present study, propofol anaesthesia compared to thiopental/isoflurane anaesthesia did not reduce the incidence of vomiting following strabismus surgery in children.

Clinical pharmacokinetics and pharmacodynamics of opioid analgesics in infants and children.

Pain in childhood has not always been managed as actively as that in adults because of the limited amount of research available to provide guidelines for the management of paediatric pain. However, for many years now the pharmacokinetics and pharmacodynamics of opioid analgesics in infants and children have been studied intensively. Morphine is the standard for opioid analgesics and its pharmacology is the best studied in paediatric patients. During the neonatal period, the volume of distribution (Vd) appears to be smaller in neonates than in adults, but adult values are reached soon after the neonatal period. Although morphine is absorbed both orally and rectally, there is little information on the pharmacokinetics of morphine administered by these routes. The bioavailability of morphine after rectal administration appears to be highly variable. For all the opioid analgesics studied, the elimination of the opioids is slower in neonates than in adults. However, the rate of elimination usually reaches and even exceeds adult values within the first year of life. The high rate of drug metabolism means higher dosage requirements. In regard to the pharmacodynamics of opioid analgesics, infants and children do not appear to be more sensitive to the effects of opioids than adults. Thus, except for the neonatal period, the pharmacokinetics and pharmacodynamics of opioid analgesics are not markedly different from those of adults, and the risk of using opioids in infants and children is not higher.

Paediatric ventilatory effects of morphine and buprenorphine revisited.

The study describes long term ventilatory effects of 50 or 100 micrograms.kg-1 of morphine or 1.5 or 3.0 micrograms.kg-1 of buprenorphine when given in repeated intravenous (i.v.) doses, in a double blind fashion, to achieve equal levels of analgesia after thoracotomy. The patients were 56 children, six months to six years of age. Ventilatory rate (VR) was measured over the 24 h study period, and arterial carbon dioxide tension (PaCO2) was measured on arrival in the Paediatric Intensive Care Unit (PICU) and at 1, 6, 12 and 18 h. In the buprenorphine groups VRs progressively decreased during the first 2 h and remained significantly lower (P < 0.05) than in the morphine groups for 7 h. For the rest of the study period there were no differences. The PaCO2 values did not differ significantly at any point. For safety, prolonged observation of children is needed after intravenous administration of buprenorphine to ensure the ventilatory rate has stabilized.

Pharmacokinetics and ventilatory effects of intravenous oxycodone in postoperative children.

1. Oxycodone hydrochloride (0.1 mg kg-1) was given by intravenous bolus to 18 children after ophthalmic surgery. Plasma was sampled for up to 8 h. Blood pressure, heart rate, peripheral arteriolar oxygen saturation, end-tidal carbon dioxide and halothane concentrations and ventilatory rate were also recorded. 2. Mean (+/- s.d.) values of drug clearance and volume of distribution (Vss) were 15.2 +/- 4.2 ml min-1 kg-1 and 2.1 +/- 0.8 l kg-1. Maximum mean end-tidal carbon dioxide concentration and minimum mean ventilatory rate occurred 8 min after administration of oxycodone but the minimum mean peripheral arteriolar oxygen saturation occurred at 4 min. 3. Oxycodone (0.1 mg kg-1) appears to cause greater ventilatory depression than comparable analgesic doses of other opioids.

Ibuprofen in the treatment of postoperative pain in small children. A randomized double-blind-placebo controlled parallel group study.

The efficacy of ibuprofen as a pre-emptive analgesic for postoperative pain was investigated in 81 children in the age between one and four years subjected to elective surgery. The patients were randomized into two groups receiving rectally either ibuprofen 40 mg.kg-1.d-1, divided into four equal doses, or placebo in a double blind manner. Additional pain relief was provided by morphine. In the recovery room ibuprofen provided superior pain relief during the first hour and significantly reduced the need of morphine. Heart rate and arterial blood pressure were lower in children who received ibuprofen, probably reflecting better analgesia. The side effects were mild and similar in both groups. We conclude that rectal ibuprofen is a safe analgesic in children in the age between 1 and 4 years and reduces the need of opioids for postoperative pain relief.

Pharmacokinetics of i.v. and rectal pethidine in children undergoing ophthalmic surgery.

We have studied the pharmacokinetics of i.v. and rectal pethidine in 20 children age 4-8 yr undergoing ophthalmic surgery. After i.v. administration, the clearance of pethidine was mean 10.4 (SD 1.7) ml kg-1 min-1, volume of distribution at steady state 2.8 (0.6) litre kg-1 and elimination half-life 3.0 (0.5) h. After rectal administration, plasma pethidine concentrations varied greatly and peak concentrations appeared late, at 147 (44) min. The mean systemic bioavailability after rectal administration was approximately 55%. Because the bioavailability of rectal pethidine varies greatly, this route is not encouraged in the management of acute pain.

Premedication with sublingual triazolam compared with oral diazepam.

The clinical effects of a new administration form of triazolam, 0.2 mg sublingual (sl) tablet, were compared with those of a 10 mg tablet of diazepam in a double-blind study, in 100 ASA I-II patients scheduled for ophthalmic surgery under local anaesthesia. The sedative and anxiolytic effects of the study drugs were followed at 15 min intervals by plotting the patient's assessments on a visual analogue scale and by a trained observer. The onset of sedative and anxiolytic effect was similar. At 75 min after premedication and after the operation triazolam 0.2 mg caused deeper sedation than diazepam 10 mg according to the observer (P < 0.001, P < 0.01) and according to the patient (P < 0.01, P < 0.05). Ten patients (20%) in the triazolam group and one in the diazepam group were assessed to be too sedated during the operation. All these patients were 61-70 yr old. The study drugs resulted in equal reduction of anxiety during the preoperative period. Both premedications provided good patient comfort but caused total amnesia only to one patient in each group. Neither caused any severe cardiorespiratory or other side effects. It is concluded that 0.2 mg triazolam sl produces deeper sedation than 10 mg oral diazepam. For elderly patients this dose is excessive for intraocular surgery.

Pharmacokinetics and pharmacodynamics of pentazocine in children.

Pharmacokinetics and ventilatory effects of a single intravenous dose of 0.5 mg/kg of pentazocine were studied in ten children aged 4 to 8 years after ophthalmic surgery. Elimination half-life (mean +/- S.D.) was 3.0 +/- 1.5 hr and clearance 21.8 +/- 5.9 ml/min./kg. The values for Vc, Vss and V beta were 0.73 +/- 0.21, 4.0 +/- 1.2 and 5.3 +/- 2.1 l/kg, respectively. The pharmacokinetic parameters were similar to those of adults. After administration of pentazocine decrease in ventilatory rate and oxygen saturation and increase in end-tidal carbon dioxide were relatively fast and steep. Oxygen saturation of four patients decreased below 90% and in one patient the decrease did not recover instantly and additional oxygen was given for 2 min. No patient needed assisted ventilation. Only clinically insignificant changes in heart rate and mean arterial pressure were observed. The duration of analgesia was 164 +/- 59 min. No serious side-effects appeared.

Comparison of the ventilatory effects of morphine and buprenorphine in children.

This study was a prospective, randomized comparison of the ventilatory effects of equianalgesic single-doses of morphine, 100 micrograms/kg, and buprenorphine, 3.0 micrograms/kg, administered intravenously to 20 children (5-8 years of age) after elective ophthalmic surgery. The decrease in ventilatory rate and acute change in the arteriolar oxygen saturation and the increase in end-tidal CO2 levels were statistically significantly greater in magnitude and duration after buprenorphine than after morphine. For both drugs, the time, duration and magnitude of ventilatory changes varied appreciably between individuals. No child had apnea or hypoventilation requiring assistance. The authors conclude that acutely administered buprenorphine depresses ventilation to a greater degree than morphine. The maximal ventilatory effect of buprenorphine occurs later than with morphine, and ventilatory depression after buprenorphine may develop late. For safety, all children given opioids intravenously should be observed until they are fully responsive and ventilatory control has stabilized.

Comparison of intravenous ketorolac with morphine for postoperative pain in children.

Ninety-two children from 3 to 12 years of age were given intravenous morphine or ketorolac by titration, or ketorolac by bolus injection for moderate or severe postsurgical pain in a double-blind randomized parallel-group study. Pain scores were assessed every 5 minutes until pain relief was complete, and then every 15 minutes for 8 hours or until pain returned. Twenty-nine of 30 patients receiving morphine and 25 of 30 patients in each group receiving ketorolac achieved pain relief. The subjects in the morphine group required statistically fewer doses for analgesia than the subjects in the ketorolac groups. The sums of pain intensity differences calculated from the start of the study numerically favored morphine, but the sum of pain intensity differences from pain relief until 50% withdrew were significantly better in the ketorolac groups. Median durations of analgesia from initial drug administration were 170, 190, and 225 minutes in the morphine, ketorolac titration, and ketorolac bolus groups, respectively. The most common side effect was injection site pain. Analgesia after intravenous ketorolac developed more slowly but was sustained better than morphine.

Efficacy of rectal ibuprofen in controlling postoperative pain in children.

The efficacy of ibuprofen with scheduled administration, starting preoperatively, for postoperative pain was studied in 128 boys and girls, 4 to 12 yr old, having elective surgery. In a double blind placebo-controlled study, rectal ibuprofen (40 mg.kg-1.day-1 in divided doses) or placebo was given for up to three days. For two hours after surgery heart rate, blood pressure and respiratory rate were recorded every 15 min together with sedation scores and pain scores, as assessed by an observer and the patient. Morphine was given to all children, 0.1 mg.kg-1 iv or 0.15 mg.kg-1 im according to clinical needs. Every morning on the ward the patients were interviewed about the efficacy of the analgesic treatment. All unwanted effects were registered. In the recovery room the heart rate was lower (P less than 0.05) and the patient's pain scores were less (P less than 0.05) in the ibuprofen group. After orthopaedic operations children needed more opioid than after ophthalmic or general surgical procedures (P less than 0.001). However, after all operations the need for additional morphine was less in the recovery room (P less than 0.05), during the day of operation (P less than 0.01) and during the three-day study period (P less than 0.01) in children receiving ibuprofen. On the day of operation the analgesic therapy was considered to be good or very good by 44/53 and 32/49 of the children in ibuprofen and placebo groups, respectively (P less than 0.05). Later, their assessments did not differ.(ABSTRACT TRUNCATED AT 250 WORDS)

The pharmacokinetics of postoperative intravenous ketorolac tromethamine in children.

Ketorolac tromethamine (0.5 mg kg-1) was given intravenously to 10 children (age 4-8 years) after minor surgery. Values of steady-state volume of distribution and plasma clearance were approximately two times higher than those in adults but values of elimination half-life were similar.