Peribulbar anesthesia: one versus two injections

BACKGROUND AND OBJECTIVE: The authors describe their prospective, randomized study of a single peribulbar injection into the junction of the lateral third and medial two thirds of the lower lid compared with the standard two-injection peribulbar technique. PATIENTS AND METHODS: One hundred twenty patients undergoing elective intraocular surgery were randomly allocated to receive either one or two injections of a mixture of balanced salt solution, 2% lidocaine, 0.5% bupivacaine, and hyaluronidase. Preoperative akinesia was assessed following the injections. At the end of surgery, the patients were asked if they had experienced any pain or discomfort during surgery. RESULTS: There was no significant difference in pain or globe akinesia between the two groups. CONCLUSION: The single peribulbar injection was found to be as effective as the standard two-injection peribulbar technique.     

Comparison of continuous spinal anaesthesia using a 32-gauge catheter with anaesthesia using a single-dose 24-gauge atraumatic needle in young patients

One hundred and twenty-eight ASA I-III patients less than 40 yr of age, undergoing orthopaedic or trauma lower limb surgery, were allocated randomly to receive either continuous spinal anaesthesia (CSA) using a 32-gauge polyimide microcatheter with a permanent stylet (Rusch/TFX Medical, Duluth, GA, USA) or single-dose spinal anaesthesia (SDSA) with a 24-gauge x 103-mm Sprotte spinal needle (Pajunk, Germany). Plain bupivacaine (0.5%) was used as the local anaesthetic. The initial doses were 1 ml (5 mg) of CSA and 3 ml (15 mg) of SDSA, while the re-injection doses were 1 ml (5 mg) in the CSA group. SDSA was quicker to perform: mean 4.4 (SD 1.6) min compared with 6.2 (2.6) min for CSA (P < 0.01). Times to onset and surgical anaesthesia were also significantly greater in the CSA group (P < 0.01). The quality of the block was better in the SDSA group (P < 0.05), but was associated with greater haemodynamic instability (P < 0.05). The segmental level of analgesia was significantly lower in the CSA group (median T10 (range T12-T8)) than in the SDSA group (T9 (T11-T5)) (P < 0.05). There were no significant differences in the incidence of postoperative complications, with two mild spinal headaches in both groups. We conclude that CSA using a microcatheter in young patients is difficult to perform and affords no advantages over SDSA with a small gauge atraumatic needle.     

Determination of deltoid fat pad thickness. Implications for needle length in adult immunization

OBJECTIVE: To measure deltoid fat pad thickness and determine the optimal needle length for deltoid intramuscular immunization in healthy adults. DESIGN, SETTING, AND PARTICIPANTS: Prospective study of 220 healthy health care workers (126 women, 94 men) at the Mayo Medical Center, Rochester, Minn. MAIN OUTCOME MEASURES: Deltoid fat pad thickness determined by high-resolution ultrasound scanning, weight, height, and mid-deltoid arm circumference. RESULTS: We found a highly significant difference between women and men in deltoid fat pad thickness, with women having a thicker deltoid fat pad (11.7 vs 8.3 mm; P<.001). Women had a greater deltoid skin-fold thickness than men (34.7 vs 17.2 mm, P<.001) and an equal body mass index. According to the ultrasound findings, a standard 16-mm (5/8-in) needle would not have reached 5 mm into muscle in 17% (16/94) of men and 48.4% (61/126) of women in this study. CONCLUSIONS: Among healthy adults of the age range we studied, the following needle lengths appear to be appropriate for true deltoid intramuscular immunization: For men across the weight ranges we studied (59-118 kg), use of a 25-mm (1-in) needle would result in at least 5 mm of muscle penetration in all subjects. For women who weighed less than 60 kg, a 16-mm (5/8-in) needle would be sufficient to achieve muscle penetration of 5 mm. For women between 60 and 90 kg, a 25-mm (1-in) needle would be sufficient, and women greater than 90 kg would require a 38-mm (1.5-in) needle to ensure intramuscular administration.     

Change in anaesthesia practice and postoperative sedation shortens ICU and hospital length of stay following coronary artery bypass surgery

We randomized prospectively 144 patients, undergoing elective coronary artery bypass surgery, to either early or to routine extubation [mechanical ventilatory support for 4-7 h (Group A), or 8-14 h (Group B)]. Anaesthesia was modified for both groups. The groups were well matched in terms of sex, age, NYHA class, preoperative left ventricular ejection fraction, bypass time and aortic cross-clamp time, number of grafts used, and blood units transfused. All patients had normal preoperative respiratory, renal, hepatic and cerebral functions. Mechanical ventilatory support (mean +/- SD) was 6.3 +/- 0.7 h for Group A and 11.6 +/- 1.3 h for Group B. Mean ICU stay was 17 +/- 1.3 h for Group A and 22 +/- 1.2 h for Group B, while the mean hospital stay was 7.3 +/- 0.8 days and 8.4 +/- 0.9, respectively. There were no statistically significant differences in the frequency of all postoperative complications among the two groups. There were no reintubation, readmission to the ICU or death in either group. We concluded that change in anaesthesia practice and early postoperative sedation in patients undergoing elective coronary artery bypass graft (CABG) surgery resulted in earlier tracheal extubation, shorter ICU and hospital length of stay without organ dysfunction or postoperative complications. Early extubation was only possible due to the modification of anaesthesia and ICU sedation regime.     

Physiology of spinal anaesthesia and practical suggestions for successful spinal anaesthesia

There are numerous physiological effects of spinal anaesthesia. This chapter focuses on the physiological effects that are of clinical relevance to the anaesthesiologist, and provides suggestions for successful management of this simple and popular technique. The mechanisms and clinical significance of spinal-anaesthesia-induced hypotension, bradycardia and cardiac arrest are reviewed. The increasing popularity of ambulatory spinal anaesthesia requires knowledge that long-acting local anaesthetics, such as bupivacaine, impair the ability to void far longer than short-acting local anaesthetics, such as lidocaine. The importance of thermoregulation during spinal anaesthesia, and the clinical consequences of spinal-anaesthesia-induced hypothermia are reviewed. Effects of spinal anaesthesia on ventilatory mechanics are also highlighted. Lastly, the sedative and minimum-alveolar-concentration-sparing effects of spinal anaesthesia are discussed to reinforce the need for the judicious use of sedation in the perioperative setting.     

Investigation on the morphokinetic reactions of the rat liver to ether anaesthesia of different length (author's transl)

The nuclear volumes were measured in the central, intermediate and peripheral zone of the classic liver lobule of adult male albino rats exposed to ether anaesthesia lasting 15, 40 and 80 min. Related to control animals there was a significantly lower nuclear size after a 40 min duration of narcosis and a significant higher volume after 80 min in the central part of the lobule. With a slight but not significant decrease of nuclear volume in the intermediate zone after 15 min and a significant increase after 80 min respectively, the peripheral lobular region constantly showed significantly smaller nuclei. But here, too, a disappearance of decrease was recorded after 80 min. The interpretation of the data is based upon a typical distribution of cell organelles, enzymatic pathways, and metabolites in the different zones of the hepatic lobule. The intensity of reaction and appearance of diminution in nuclear volume, indicating a functional depression and probably accentuated by a circular dependent low O2-tension of tissue, is interpreted in connection with different local concentrations of ether. An improvement of the blood flow by augmental local metabolites and an increased arterial influx presumably support the recovery and favour a concentration-dependent induction of microsomal enzymes in the central part of the lobule especially.     

New needle for two needle hemodialysis

A new venous needle (VN) that also can be used as an arterial needle (AN) has been designed to diminish the undesirable hemodynamic effects of dialysis with high blood flow rate (300-600 ml/min) in arteriovenous polytetrafluoroethylene grafts, and in accesses of short length (U.S. Patent No. 5,662,619). The preferred embodiment has one distal opening, two lateral openings, and two diverters located in the interior surface of the shaft adjacent to each lateral opening. The diverters facilitate the flow of blood to the outside of the needle through the lateral openings. The new VN ejects three jets of blood, contrary to the currently used VN, which ejects one jet of high velocity. This decreases the velocity of the VN flow and the velocity; turbulence; wall shear stress; and positive pressure of the flow, past the VN, during dialysis. These may decrease the endothelial damage, intimal hyperplasia, stenoses, thromboses, and recirculation of dialysis blood (RODB). When used as an AN, the new needle lowers the negative pressure surrounding the AN and the RODB. In summary, the new needle may decrease the complications and prolong the life span of the accesses and improve the performance of dialysis.     

Peribulbar and retrobulbar anesthesia with prilocaine: a comparison of two methods of local ocular anesthesia

Prilocaine (Citanest) has been shown to be a satisfactory alternative to lignocaine, with certain important advantages, including superior diffusion. The latter may be especially important in peribulbar anesthesia, where the level of diffusion is a critical factor in providing a timely, high-quality block. In a prospective randomized study, we compared the effectiveness of peribulbar vs retrobulbar administration of prilocaine. Eighty-seven patients undergoing elective intraocular surgery were randomized to receive either retrobulbar or peribulbar anesthesia with prilocaine 3% with felypressin and hyaluronidase. Pain of injection, akinesia, and anesthesia were evaluated at predetermined intervals after injection. Except for the fact that lid akinesia occurred earlier in the peribulbar group, there was no difference in the quality or rate of onset of overall akinesia in the two groups. Nor were there any differences in the pain associated with injection. Both groups had excellent operative anesthesia and akinesia.     

Laparoscopic and needle colposuspension

A deletion mutant ScrY delta 3-73 of the sucrose-specific porin ScrY was constructed in which 70 amino acids of the mature protein were deleted near the N-terminal end. ScrY delta 3-72 was still able to oligomerize and inserted properly into the outer membrane of an Escherichia coli strain. The protein was isolated and purified by standard procedures. The mutant protein showed, in contrast to wild-type ScrY, a tight association with the murein. Reconstitution experiments with artificial lipid bilayer membranes demonstrated that ScrY delta 3-72 produced defined cation-selective channels in planar lipid bilayers. Its single-channel conductance was reduced to about half of the value of wild-type ScrY. The deletion had a relatively small influence on the stability constants for carbohydrate binding. However, in contrast to wild-type ScrY, [14C]-maltopentaose was efficiently taken up into whole E. coli cells containing ScrY delta 3-72. The sequence of the N-terminus of mature ScrY was identified as starting with glutamine 23. The possible structure of ScrY and ScrY delta 3-72 in the outer membrane is discussed.     

Difficult intubation and brain-stem anaesthesia

PURPOSE: To present a case of difficult intubation with brainstem anaesthesia after retrobulbar block with bupivacaine and lidocaine and sedation with midazolam and to point out that close monitoring and timely treatment is important in preventing an unfavourable outcome. CLINICAL FEATURES: An 82-yr-old man with treated hypertension and stable angina was scheduled for cataract extraction. Physical examination revealed a class 2 airway. He had a retrobulbar block after topical tetracaine drops, with bupivacaine 0.5% and lidocaine 2% with hyaluronidase under sedation with 1 mg midazolam. Five minutes after the block, respiration slowed, he became unresponsive and oxygen saturation decreased to 80%. Immediate ventilation with mask without additional oxygen improved saturation. Attempted tracheal intubation failed: the epiglottis could not be visualized despite flaccid jaw and extremities. A laryngeal mask airway was placed which was leaking and adequate ventilation could not be achieved but a second laryngeal mask airway was placed successfully. CONCLUSION: This case emphasizes the need for dose monitoring and personnel capable of managing the difficult airway when intra-orbital anaesthesia is used.     

Spinal anaesthesia and spina-bifida occulta

We describe a patient with unexpected spina bifida who underwent spinal anaesthesia for trans-urethral resection of prostate and developed serious neurological signs. An unexpected spinal tumour was removed two weeks later. This report demonstrates that not all neurological problems associated with spinal anaesthesia should be blamed on the technique.     

Epidural anaesthesia and spinal haematoma

PURPOSE: Haematoma formation in the spinal canal due to epidural anaesthesia is a very rare but serious complication. This paper presents a comprehensive review of case reports. SOURCE: Sampling of case reports over a 10 yr period, medline-research (1966-1995) and cross-check with former reviews. FINDINGS: Fifty-one confirmed spinal haematomas associated with epidural anaesthesia were found. Most were related to the insertion of a catheter, a procedure that was graded as difficult or traumatic in 21 patients. Other risk factors were: fibrinolytic therapy (n = 2), previously unknown spinal pathology (n = 2), low molecular weight heparin (n = 2), aspirin or other NSAID (n = 3), epidural catheter inserted during general anaesthesia (n = 3), thrombocytopenia (n = 5), ankylosing spondylitis (n = 5), preexisting coagulopathy (n = 14), and intravenous heparin therapy (n = 18). CONCLUSION: Coagulopathies or anticoagulant therapy (e.g., full heparinization) were the predominant risk factors, where-as low-dose heparin thromboprophylaxis or NSAID treatment was rarely associated with spinal bleeding complications. Ankylosing spondylitis was identified as a new, previously unreported risk factor. Analysis of reported clinical practice suggests an incidence of haematoma of 1:190,000 epidurals.     

Peribulbar anesthesia. A prospective statistical analysis of the efficacy and predictability of bupivacaine and a lignocaine/bupivacaine mixture

Involvement of endogenous nitric oxide (NO) on glutamate receptor-mediated response was investigated in neuronal cells cultured from embryonic rat hippocampus. L-NG-Nitroarginine (NOARG), a NO synthase inhibitor, augmented NMDA- and kainate-induced increase in intracellular Ca2+ concentration ([Ca2+]i) measured by fura-2 fluorometry. However, quisqualate-induced response was not affected. The potentiating effect of NOARG was blocked by L-arginine, a substrate for NO synthase. NOARG was also effective when added after glutamate-induced response had reached a steady-state. Hemoglobin itself increased the basal level of [Ca2+]i at concentrations higher than 10 mM, and treatment of the cells with 1.0 mM hemoglobin had no effect on NMDA response. 8-Bromo-cyclic GMP was not effective on NMDA response. These results suggest that endogenous NO inhibits NMDA- and kainate-induced increase in [Ca2+]i as a negative feedback system independent of guanylate cyclase activation.     

Continuous spinal anaesthesia

CD59 is a cell membrane-bound complement regulatory protein on glomerular cells that inhibits C5b-9 assembly and insertion. This report describes a recently developed model of immune thrombotic microangiopathy (TMA) induced by the renal artery perfusion of anti-glomerular endothelial cell (anti-GEN) antibody. To examine the role of CD59 in protecting the GEN from immune-mediated injury, rats underwent selective renal artery perfusion with F(ab')2 fragments of anti-CD59 monoclonal antibody to block CD59 activity or control mouse IgG followed by anti-GEN antibody or control goat IgG. Neutralization of CD59 in normal rats did not result in any significant functional or histologic changes. Perfusion with anti-CD59 did not change deposition of the pathogenic anti-GEN IgG used to induce the TMA model. However, neutralization of CD59 in the TMA model resulted in more C5b-9 formation in glomeruli, accompanied by increased platelet and fibrin deposition, more severe endothelial injury, and reduced renal function compared with the animals perfused with control F(ab')2 fragments. These results demonstrate directly that CD59 serves a protective role for GEN in this TMA model of rats, and confirm that C5b-9 formation has a critical pathogenic role in the mediation of the disease. CD59 may play an important role in protecting glomerular endothelium from other complement-mediated types of injury.