Peribulbar anaesthesia: a double-blind comparison of three local anaesthetic solutions

Efficacy and safety of 0.5% levobupivacaine versus 0.5% bupivacaine for peribulbar anesthesia

Background

This randomized double-blind study examined the use of a new anesthetic agent, levobupivacaine 0.5%, which is the S(−)-enantiomer of a racemic mixture of bupivacaine, for peribulbar anesthesia and compared it with racemic bupivacaine 0.5% alone or in combination with hyaluronidase 10 IU/mL.

Methods

A total of 160 patients undergoing ophthalmic surgery were randomized into four groups (n = 40 each) to receive inferotemporal peribulbar injection of levobupivacaine 0.5% (group L), racemic bupivacaine 0.5% (group B), levobupivacaine + hyaluronidase 10 IU/mL (group LH), or racemic bupivacaine + hyaluronidase 10 IU/mL (group BH) by two anesthetists and two ophthalmologists in a ratio of 25% each. Ocular akinesia and orbicularis oculi function were evaluated using a three-point scale; a value < 5 points was considered as requiring surgery, and movements were re-evaluated the day following surgery to confirm regression of the block.

Results

The time to onset (12 ± 2.6 minutes versus 13 ± 2.8 minutes) and duration of anesthesia (185 ± 33.2 minutes versus 188 ± 35.7 minutes) were similar between groups L and B. Complete akinesia (score 0) was obtained more frequently when hyaluronidase was used in addition to the anesthetic, with occurrences of 72.5% versus 57.5% in group LH versus L, respectively, and 67.5% versus 45% in group BH versus B. Moderate hypotension (<30% of baseline) was observed in four patients (10%) in group L, two (5.0%) in group B, one (2.5%) in group LH, and three (7.5%) in group BH. The time to onset was significantly different between groups L and BH, B and BH, and LH and BH, and the duration of anesthesia differed significantly between groups B and LH, B and BH, and L and LH. The akinesia score differed significantly between groups L and LH and between groups B and LH (P = 0.043 and P = 0.018, respectively), and the number of patients with a score of 0 differed significantly between groups B and LH and between groups B and BH (P = 0.004 and P = 0.017, respectively).

Conclusion

Levobupivacaine is a long-lasting local anesthetic with limited cardiotoxicity and neurotoxicity, and may be considered the landmark for vitreoretinal surgery in elderly patients.

Single-injection percutaneous peribulbar anesthesia with a short needle versus sub-Tenon's anesthesia for cataract extraction

Purpose:

This study compared the efficacy of single-injection percutaneous peribulbar anesthesia (PBA) with a short needle with sub-Tenon's anesthesia (STA) to produce optimal operating conditions for cataract extraction in patients with complicated cataract.

Methods:

Two hundred patients with complicated cataract were enrolled in this prospective, double-blinded, randomized study. Adequate akinesia was a surgical requisite for all cases included in the study because of the expected difficult surgery. The patients were divided into two equal groups to receive either peribulbar anesthesia (PBA) with a 16-mm needle or sub-Tenon's anesthesia. Surgical akinesia (as a primary end point), analgesia, incidence of complications, as well as patient and surgeon satisfaction (as secondary end points) were assessed.

Results:

Both techniques provided similar analgesia during the operation and similar rates of incidence of chemosis with no serious complications; while the PBA group provided higher degree of akinesia 10 minutes after injection of the local anesthetic, a lower incidence of subconjunctival hemorrhage (SCH) and higher patient and surgeon satisfaction compared to the STA group.

Conclusion:

We concluded that when globe akinesia is necessary during surgery, the single-injection technique for percutaneous peribulbar anesthesia with a short needle proved to be more suitable than the STA in providing akinesia for cataract surgery. Also, this PBA technique demonstrated a lower incidence of SCH and was preferred to STA by the patients and surgeon.

Felypressin, but not epinephrine, reduces myocardial oxygen tension after an injection of dental local anesthetic solution at routine doses

PURPOSE

The aim of this study was to evaluate the effect of epinephrine (Epi) or felypressin (Fely) contained in dental local anesthetics on myocardial oxygen balance.

MATERIALS AND METHODS

Male Japanese White tracheotomized rabbits were anesthetized with isoflurane. Three doses of 0.18, 0.36, and 0.72 mL of 2% lidocaine hydrochloride containing 1:80,000 Epi or 3% prilocaine hydrochloride containing Fely 0.03 IU/mL were injected into the rabbit tongue muscle. These doses were equivalent to 2, 4, and 8 of dental local anesthetic cartridges in humans weighing 50 kg by body weight correction, respectively. Heart rate, blood pressure, aortic blood flow, myocardial tissue blood flow, and myocardial tissue oxygen tension were continuously monitored. Data were recorded immediately before and 10, 20, 30, and 60 minutes after the injection.

RESULTS

Heart rate decreased in the Fely group. Systolic blood pressure increased in the Epi group, and diastolic blood pressure increased in both groups. Aortic blood flow and myocardial tissue blood flow increased, whereas myocardial tissue oxygen tension did not change in the Epi group. In contrast, aortic blood flow, myocardial tissue blood flow, and myocardial tissue oxygen tension decreased in the Fely group.

CONCLUSION

It is suggested that Fely, but not Epi, decreases myocardial oxygen tension and aggravates myocardial oxygen demand/supply balance even after an injection of dental local anesthetic solution at routine doses.

Intraocular pressure and quality of blockade in peribulbar anesthesia using ropivacaine or lidocaine with adrenaline: a double-blind randomized study

The aim of this study was to compare the effects of ropivacaine with those of lidocaine on the intraocular pressure (IOP) and the quality of the blockade in peribulbar anesthesia for cataract surgery. Fifty patients were allocated randomly into two groups and received 7-10 ml of 0.75% ropivacaine or 2% lidocaine with adrenaline, though the peribulbar two-point injection. The quality of the blockade was assessed by ocular and eyelid akinesia, pain during the peribulbar injection, and surgical satisfaction. The duration of the motor block was also evaluated after surgery. The IOP was measured using a Tonopen before the blockade (control) and at 1, 5, and 10 min after injection of the anesthetic. Lidocaine induced significantly lower akinesia scores at 6, 8, and 10 min post-injection than did ropivacaine. The mean IOP (mmHg) was significantly lower with respect to the baseline level at 10 min after blockade in the ropivacaine group compared with the lidocaine group. Ropivacaine also caused less pain on injection. There was no difference in surgical satisfaction between the groups. The duration of the motor block obtained with ropivacaine was longer than that obtained with lidocaine. Our data indicate that ropivacaine has efficacy similar to lidocaine, with slightly longer onset and duration of the motor blockade. In addition, ropivacaine (0.75%) induces lower IOP and less pain on injection than does lidocaine (2%) when used in peribulbar anesthesia for cataract surgery.

L’anesthésie topique en chirurgie de la cataracte ambulatoire de l’adulte sans anesthésiste présent

To review the local anesthesia environment in France in adult out-patient cataract surgery. The author considers the presence or absence of an anesthesiologist in the operating room. The report shows that in many circumstances there is no need for an anesthesiologist if the following criteria are respected: the adult is fully informed, in rather good health, with no acute risk factors, and surgery is performed by a senior surgeon in a certified operating room. In France, a move toward more flexible regulations is expected, with a new cooperation between ophthalmologists and anesthesiologists that will lead to a new true risk/benefit/obligation ratio. Respect of the individual and safety remain crucial requirements making systematic generalizations impossible.

Can acupuncture reduce the induction time of a local anaesthetic?--A pilot study

We report on a pilot study we undertook to investigate if segmental acupuncture treatment, given two minutes prior to a regional inferior dental block (ID) with Prilocaine Hydrochloride, would reduce the onset time of a local anaesthetic. Thirty healthy people, who needed a regional inferior dental block (ID) as part of dental treatment in the lower jaw, were randomly allocated to three groups. They received segmental acupuncture, heterosegmental superficial acupuncture, or standard treatment (regional inferior dental block) without acupuncture. In the segmental acupuncture group, acupuncture was given within the innervation of the trigeminal nerve. The needles were left in for two minutes, followed by a regional inferior dental block (ID). In the second group, acupuncture needles were inserted superficially in extra-segmental points and left in for two minutes without stimulation, followed by the regional inferior dental block. A control group received standard treatment only, of a regional inferior dental block. The concept 'pain free for dental work' was defined as 'patients reporting pins and needles in the lower lip' and measured by a drilling test. Patients who reported no pain during the drilling test were included in the study. The time from administration of the injection to the patients' reporting pins and needles was recorded by an independent dental nurse. All tested patients reported sufficient anaesthesia during the drilling test. In the segmental acupuncture group, anaesthesia was achieved after 62 seconds, compared to the heterosegmental superficial acupuncture group, who took 115 seconds and the control group, who received standard treatment only, and took 119 seconds. The difference between the segmental acupuncture group and the heterosegmental superficial acupuncture group was statistically significant (p < 0.015); the difference between the segmental acupuncture group and the control, who received a regional inferior dental block only, was also significant (p < 0.032). No significant difference was found between the heterosegmental superficial acupuncture group and the control group who received a regional inferior dental block only (p < 0.84). It appears from this pilot study that the onset time of local anaesthesia is reduced if segmentally administered acupuncture is given prior to the regional inferior dental block. However, it needs to be reproduced including objective measurements.

Local anaesthesia for vitreoretinal surgery: an audit of patient and surgical experience

PURPOSE

Local anaesthesia for vitreoretinal surgery is little used as these procedures are deemed to be too long and uncomfortable for patients to tolerate. In this unit anterior intraconal local anaesthesia is used for most routine surgery. We undertook an audit to ensure that surgical standards and patient acceptability were not compromised.

METHODS

A prospective observational audit was performed. Audit data included: Grade of anaesthetist and surgeon; details of anaesthetic and operation; compliance of patient; operating conditions and pain scores. Anaesthesia was provided with a combined peribulbar and intraconal anaesthetic, using bicarbonate buffered lignocaine and bupivacaine 50:50 mixture.

RESULTS

135 (76%) had local anaesthesia alone, 13 (7%) had local anaesthesia with sedation and 29 (16%) had general anaesthesia. 96.4% of patients were compliant and 98.8% of operating conditions were good or excellent. The mean perioperative pain score was 0.1 (range of 0-1), 97% said they would choose local anaesthesia again.

CONCLUSIONS

LA for vitreoretinal surgery is a useful and flexible method of anaesthesia, which has been shown to have excellent patient tolerance.

A double-blind randomised comparison of ropivacaine 0.5%, bupivacaine 0.375% - lidocaine 1% and ropivacaine 0.5% - lidocaine 1% mixtures for cataract surgery

This study evaluated the efficacy and side-effects of plain ropivacaine compared with ropivacaine-lidocaine and bupivacaine-lidocaine mixtures for peribulbar blocks in cataract surgery. Ninety patients were randomly allocated to three groups and received peribulbar blockade using one of the three solutions. Speed of onset and quality of blockade were assessed using akinesia, surgical satisfaction and patient satisfaction. Complications and cardiovascular side-effects were noted. There was a slower onset of akinesia using ropivacaine alone, although at 10 min after injection all groups were equal in this respect. There was no difference in surgical or patient satisfaction between the groups. There were no differences in pain on injection, preblock and postblock blood pressure, heart rate or oxygen saturation. The optimal time to surgical incision after peribulbar blockade is not less than 15 min and plain ropivacaine fulfils this criterion.

Single injection peribulbar anaesthesia. Total upper eyelid drop as an end-point marker

A prospective, observer blinded study on 51 patients undergoing cataract surgery was conducted to assess Total Upper Eyelid Drop as a new end-point marker to single injection peribulbar block. At present, no such clinical marker exists to stop clinicians injecting more than necessary volumes of local anaesthetic and therefore to prevent dangerous increases in intra-ocular pressure. Using this technique, satisfactory ocular akinesia was achieved in 90% of eyes 10 min after injection. Operating conditions were satisfactory in 98% of cases. The mean (range) volume injected was 9.1 (4-15) ml. The mean increase in intra-ocular pressure immediately after injection was 6.9 mmHg, decreasing to 0.7 mmHg after 5 min without the application of ocular compression. We found a negative correlation between the increase in intra-ocular pressure and the volume of injection (p < 0.002), which has never previously been reported. We conclude that Total Upper Eyelid Drop is a reliable endpoint marker for producing satisfactory operating conditions for cataract surgery while minimising increases in intra-ocular pressure and its use may therefore avoid the risks associated with ocular compression.

Recent developments in regional anesthesia for ambulatory surgery

The use of regional anesthesia techniques is increasing in popularity because they reduce the incidence of postoperative complications, including nausea, vomiting, and pain, and decrease the recovery time and hospital stay. This article reviews the recent developments in regional anesthesia techniques and the modifications necessary to adapt them for ambulatory surgery.