Single-Injection Percutaneous Peribulbar Anesthesia with a Short Needle as an Alternative to the Double-Injection Technique for Cataract Extraction

Ketamine versus midazolam as an adjuvant to peribulbar block using a single inferonasal injection in patients undergoing vitreoretinal surgery: A randomized controlled trial

INTRODUCTION AND OBJECTIVES

This study aimed to assess the safety and efficacy of midazolam and ketamine as adjuvants to the peribulbar block in vitreoretinal surgeries.

PATIENTS AND METHODS

This randomized controlled trial included 93 adult patients undergoing vitreoretinal surgeries performed with peribulbar anaesthesia. Patients were randomly allocated to 3 groups (31 participants each): control (standard anaesthetic mixture), midazolam (standard mixture + midazolam), and ketamine (standard mixture + ketamine). The primary outcomes were onset of globe akinesia and duration of analgesia. Secondary outcomes were duration of motor blockade, onset of corneal anaesthesia and lid akinesia, and changes in vital data (blood pressure, oxygen saturation, and pulse rate).

RESULTS

The ketamine group vs. the control and midazolam groups showed the most rapid onset of lid and globe akinesia (p < 0.001) and corneal anaesthesia (0.7 ± 0.2 vs. 1.5 ± 0.5 and 1.2 ± 0.4, respectively; p < 0.001) and the longest duration of both analgesia (3.7 ± 0.6 vs. 2.3 ± 0.4 and 3.1 ± 0.6, respectively; p < 0.001) and akinesia (3.8 ± 0.5 vs. 3.0 ± 0.4, and 3.7 ± 0.5, respectively; p < 0.001). The midazolam group showed better outcomes than controls, but the drug was less effective than ketamine. There were no significant differences in vital data among groups (p > 0.05).

CONCLUSIONS

Ketamine is an effective adjuvant for peribulbar blockade. It enhances both motor and sensory blockade by hastening onset and prolonging duration. These effects are desirable in lengthier ophthalmic procedures such as vitreoretinal surgeries. The effects of ketamine were superior to those of midazolam.

Ketamine versus magnesium sulphate as an adjuvant to local anesthetics in the peribulbar block for posterior segment surgeries: a randomized controlled study

BACKGROUND

The use of an adjuvant to local anesthetics in the peribulbar block may improve block characteristics. The aim of this double-blinded, parallel-group, randomized, controlled trial was to evaluate the safety and efficacy of ketamine versus magnesium sulphate as adjuvants to the local anesthetic mixture of peribulbar block in patients scheduled for vitreoretinal surgeries.

METHODS

A total of 126 patients scheduled for vitreoretinal surgery were randomly allocated as either ketamine (GK, n=42), magnesium sulphate (GM, n=42), or control (GC, n=42) groups. The primary outcomes were the onset and duration of globe akinesia, duration of lid akinesia, and onset of sensory block. Secondary outcomes included time to start surgery, duration of analgesia, intraocular pressure, and patient and surgeon satisfaction.

RESULTS

The use of either ketamine or magnesium significantly shortened the onset of globe akinesia, enhanced the onset of sensory block, prolonged the duration of globe and lid akinesia, minimized the time required to start surgery, and increased the total analgesic time. The effect of magnesium was significantly more pronounced on durations of globe and lid akinesia as well as analgesia, whereas ketamine significantly shortened the time required to start surgery. Both patient and surgeon satisfaction were significantly improved with the use of either drug.

CONCLUSIONS

In vitreoretinal surgeries the use of either ketamine or magnesium sulphate as adjuvants to the local anesthetic mixture of peribulbar block improved the onset, duration, and quality of the block, offered better patient and surgeon satisfaction, and was not associated with drug adverse effects or surgical complications.

Minimum effective volume of local anesthetic in peribulbar block: does it differ with the eyeball axial length?

Background

Peribulbar Anesthesia (PBA) is a relatively safe method for cataract surgery. The anesthetic volume should be adjusted according to the axial eyeball length. Thus, using Minimum Effective Volume (MEV) of local anesthetic helps avoiding unnecessary volumes, preventing increases in intra-ocular pressure, and producing satisfactory conditions for cataract surgery. This study aims to determine the MEV90 of local anesthetics in relation to eye globe axial length in peribulbar blocks for cataract surgery.

Methods

Patients scheduled for cataract extraction under local anesthesia were divided according to their axial eyeball length; Group 1 included those with axial length from 22 to 24 mm, Group 2 included patients with axial length from 24.1 to 26 mm. The initial volume used was 7 mL of a solution of bupivacaine 0.5% (3 mL) + lidocaine 2% (3 mL) + hyaluronidase 150 IU (1 mL). The subsequent volumes were dependent on the response of the previous patient, by using a Bias Coin Design (BCD) and Up and Down Method (UDM) for MEV-90 determination.

Results

The study was concluded with 119 patients. Sixteen patients needed supplemental volume of local anesthetic in Group 1 and thirteen in Group 2. The MEV90 for Group 1 was approximately 5.82 mL (95% CI 5.6 to 5.87 mL) and 5.45 mL for Group 2 (95% CI 5.38 to 5.91 mL). No major complications were noted. There was a negative correlation between the effective volume of LA and eye globe axial length in both groups (p = 0.001).

Conclusion

The MEV90 of local anesthetics for peribulbar block show a strong and inverse correlation with eye globe axial length. This may help achieving an effective block with minimum complications.

Comparison of orbital muscle akinesia caused by rocuronium versus hyaluronidase mixed to the local anesthetic in single injection peribulbar block for cataract surgery

Background:

The aim of this study was to compare orbital muscle akinesia caused by rocuronium versus hyaluronidase when mixed with the local anesthetic in single-injection peribulbar anesthesia (PBA).

Patients and Methods:

Sixty patients were included in the study and subjected to cataract extraction using phacoemulsification technique with intraocular lens implantation. Group I received peribulbar block with 5 ml mixture of 30 IU/ml hyaluronidase and 2% lidocaine. Group II received peribulbar block with 5 ml mixture of rocuronium 5 mg and 2% lidocaine. The onset and duration of akinesia were assessed; the akinesia score at 2, 5, and 10 min was measured after injection. The need for supplementary injection was also recorded.

Results and Conclusion:

PBA using a mixture of rocuronium and lidocaine provides optimal globe akinesia and faster establishment of suitable conditions to start eye surgery and shortens the block onset time as compared with the addition of hyaluronidase to lidocaine.

A qualitative study of regional anaesthesia for vitreo-retinal surgery

AIM

The aim of this research was to collect experiential knowledge about regional ocular anaesthesia - an integral component of most vitreo-retinal surgery.

BACKGROUND

Anaesthesia for vitreo-retinal surgery has predominantly used general anaesthesia, because of the length and complexity of the surgical procedure. However, recent advances in surgical instrumentation and techniques have reduced surgical times; this decision has led to the adoption of regional ocular anaesthesia for vitreo-retinal day surgery. Although regional ocular anaesthesia has been studied from several perspectives, knowledge about patients' experience of the procedure is limited.

DESIGN

An interpretive qualitative research methodology underpinned by Gadamer's philosophical hermeneutics.

METHODS

Eighteen participants were interviewed in-depth between July 2006-December 2007 following regional ocular anaesthesia. Interview data were thematically analysed by coding and grouping concepts.

FINDINGS

Four themes were identified: 'not knowing': the time prior to the experience of a regional eye block; 'experiencing': the experience of regional ocular anaesthesia; 'enduring': the capacity participants displayed to endure regional ocular anaesthesia with the hope that their vision would be restored; and 'knowing': when further surgery was required and past experiences were recalled.

CONCLUSIONS

The experience of regional ocular anaesthesia had the capacity to invoke anxiety in the participants in this study. Many found the experience overwhelming and painful. What became clear was the participant's capacity to stoically 'endure' regional ocular anaesthesia, indicating the value people placed on visual function.

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.