Procedural pain of an ultrasound-guided brachial plexus block: a comparison of axillary and infraclavicular approaches.

BACKGROUND: Ultrasound (US)-guided infraclavicular (IC) and axillary (AX) blocks have similar effectiveness. Therefore, limiting procedural pain may help to choose a standard approach. The primary aims of this randomized study were to assess patient's pain during the block and to recognize its cause. METHODS: Eighty patients were randomly allocated to the IC or the AX group. A blinded investigator asked the patients to quantify block pain on a Visual Analogue Scale (VAS 0-100) and to indicate the most unpleasant component (needle passes, paraesthesie or local anaesthetics injection). Sensory block was assessed every 10 min. After 30 min, the unblocked nerves were supplemented. Patients were ready for surgery when they had analgesia or anaesthesia of the five nerves distal to the elbow. Preliminary scan time, block performance and latency times, readiness for surgery, adverse events and patient's acceptance were recorded. RESULTS: The axillary approach resulted in lower maximum VAS scores (median 12) than the infraclavicular approach (median 21). This difference was not statistically significant (P=0.07). Numbers of patients indicating the most painful component were similar in both groups. Patients in either group were ready for surgery after 25 min. Two patients in the IC group and seven in the AX group needed block supplementation (n.s.). Block performance times and number of needle passes were significantly lower in the IC group. Patients' acceptance was 98% in both groups. CONCLUSIONS: We did not find significant differences between the two approaches in procedural pain and patient's acceptance. The choice of approach may depend on the anaesthesiologist's experience and the patient's preferences.

A comparison of ultrasound-guided supraclavicular and infraclavicular blocks for upper extremity surgery.

BACKGROUND: Ultrasound (US)-guided supraclavicular or infraclavicular blocks are commonly used for upper extremity surgery. The aims of this randomized study were to compare the block performance and onset times, effectiveness, incidence of adverse events and patient's acceptance of US-guided supraclavicular or infraclavicular blocks. We hypothesized that the supraclavicular approach, being more superficial and easier to visualize using a 10 MHz transducer, will produce a faster and a more extensive sensory block. METHODS: One hundred and twenty patients were randomized to two equal groups: supraclavicular (S) and infraclavicular (I). Each patient received a mixture containing equal volumes of ropivacaine 7.5 mg/ml and mepivacaine 20 mg/ml with adrenaline 5 microg/ml, 0.5 ml/kg body weight (minimum 30 ml, maximum 50 ml). The sensory score (anaesthesia--2 points, analgesia--1 point and pain--0 point) of the seven terminal nerves was assessed every 10 min. Patients were declared ready for surgery when they had an effective surgical block--anaesthesia or analgesia of the five nerves below the elbow. Thirty minutes after the block, the unblocked nerves were supplemented. The block performance and latency times, surgical effectiveness, adverse events and patient's acceptance were recorded. RESULTS: Significantly more patients in the I group were ready for surgery 20 and 30 min after the block. The mean block performance time was 5.7 min in the S group and 5.0 min in the I group (NS). Block effectiveness was superior in the I group: 93% vs. 78% in the S group (P=0.017). The S group patients had a significantly poorer block of the median and ulnar nerves, but a better block of the axillary nerve. Sensory scores at 10, 20 and 30 min were not significantly different. Thirty-two patients in the S group vs. nine patients in the I group experienced transient adverse events (P<0.0001). Patients' acceptance of the block was similar in both groups. CONCLUSIONS: Infraclavicular block had a faster onset, better surgical effectiveness and fewer adverse events. Block performance time and patients' acceptance of the procedure were similar in both groups.

Biphasic cardiac output changes during onset of spinal anaesthesia in elderly patients.

BACKGROUND AND OBJECTIVE: In most studies of cardiac output changes after spinal anaesthesia, the time-resolution is limited. The aim of this study was to demonstrate cardiac output changes with high time-resolution during onset of spinal anaesthesia in elderly patients. METHODS: We investigated 32 patients aged 60 yr scheduled for elective lower limb surgery. Fourteen received concurrent cardiovascular medication. Cardiac output was measured every 10 s using a pulse wave algorithm derived from the radial artery pressure curve, after calibration with lithium chloride (LiDCOplus). Data collection ended when the patients were ready for surgery, or if ephedrine was given to raise the mean arterial pressure. RESULTS: Cardiac output increased initially reaching a maximum after a mean of 7 min. The average increase was 1.1 L min(-1) (P<0.0001). This occurred when mean arterial pressure was reduced 14 mmHg on average. At the end of data collection, cardiac output decreased 0.5 L min(-1) from baseline (P=0.02). Mean arterial pressure decreased progressively in all patients, and only minimal changes in heart rate were found. CONCLUSIONS: Using this high time-resolution method, we detected biphasic changes in cardiac output during onset of spinal anaesthesia. Initially, cardiac output increased. Subsequently, it was significantly reduced from baseline, although this decrease was of minor clinical importance.

Infraclavicular block causes less discomfort than axillary block in ambulatory patients.

BACKGROUND: This randomized study was designed to compare discomfort caused by axillary or infraclavicular blocks in ambulatory patients. We identified which of the three block components, needle passes, local anesthetic (LA) injections, and electrical stimulations, is most painful and quantified pain intensity on a visual analog scale (VAS 0-100). We also assessed onset and quality of analgesia, adverse events and patients' acceptance. METHODS: Eighty patients were studied. In axillary group-A, four LA injections were made after stimulating median, musculocutaneous, ulnar and radial nerves. In infraclavicular group-I, the whole LA volume was injected after stimulating median or ulnar or radial nerves. Patients were ready for surgery when they had analgesia/anesthesia distal to the elbow. RESULTS: Median intensity of block discomfort was 22 in A group and 10 in I group (P < 0.01). There was no difference in distribution of the most painful block components between the groups. Block performance times were 4 min in I group and 7 min in A group (P < 0.01). Block onset times were 18 min in A group and 20 min in I group (NS). There was one block failure in I group. Three patients in A group and five in I group required supplementary blocks (NS). Transient adverse events occurred in 14 A-group and two I-group patients (P<0.01). Thirty-seven I-group and 33 A-group patients were satisfied with the block (NS). CONCLUSIONS: Infraclavicular block by single injection caused less discomfort and fewer adverse events than axillary block by multiple injections. Block effectiveness, onset time and patients' acceptance were similar.

High antibiotic consumption in Danish intensive care units?

Decreased antibiotic susceptibility among microorganisms isolated from intensive care unit (ICU) patients is found to be associated with high total antibiotic consumption or inappropriate use of antibiotics in the ICUs. The aims of this study were: 1) to characterize the antibiotic consumption in Danish ICUs, and in four ICUs with expectedly large differences in levels of antibiotic consumption, 2) to estimate the association between antibiotic susceptibility among isolated microorganisms and antibiotic consumption. This was done by: 1) a retrospective questionnaire study of the annual supply of antibiotics in 1995 to 30 ICUs in Denmark, and 2) a 2-month prospective study of patients and microbiological samples in four Danish ICUs in 1996. We found that the supply of antibiotics to Danish ICUs was substantial, with a median value of 124 DDD/100 patient days. No association was found between high consumption of antibiotics and decreased antibiotic susceptibility in the four ICUs.

Comparison of transarterial and multiple nerve stimulation techniques for an initial axillary block by 45 mL of mepivacaine 1% with adrenaline.

BACKGROUND: The single-injection axillary block is rapidly performed but gives unpredictable results. Axillary block by multiple nerve stimulation technique (MNS) gives better results, but takes longer to perform. Transarterial (TA) injections of high doses of local anaesthetics are very successful. This double-blind study compared both block effectiveness and anaesthesiologic time consumption in 100 patients, having an axillary block by either TA or MNS techniques. METHODS: 45 mL of 1% mepivacaine with adrenaline 5 microg/mL was used in each patient. Five mL was injected subcutaneously. In the TA group, 20 mL was injected deep to, and 20 mL superficial to the axillary artery. In the MNS group, four terminal motor nerves were electrolocated in the axilla, and injected with 10 mL each. Analgesia was assessed every 10 min and when needed supplemented after 30 min. The block was considered successful when analgesia was present in all sensory nerve areas distal to the elbow. RESULTS: MNS group required 10+/-2 min (mean+/-1 SD) for the initial block performance compared with 7+/-2 min for TA group, P<0.001. Latency of the initial block was shorter and the frequency of supplemental analgesia lower in the MNS group (mean 17 min and 12%), than in the TA group (25 min and 38%, respectively), P<0.001. All incomplete blocks were successfully supplemented by electrolocating the unblocked nerves. However, the total time to obtain 100% success rate was shorter in the MNS group (30 min), than in the TA group (38 min), P<0.001. The adverse effects (accidental intravascular injections and axillary haematomas) were fewer in the MNS group. CONCLUSION: In the hands of anaesthetists experienced in nerve electrolocation, the MNS technique of an initial axillary block by four separate injections of 10 mL of mepivacaine produces faster and more extensive block than the TA technique by two separate injections of 20 mL. Hence, the MNS technique requires fewer supplementary blocks and results in faster patient readiness for surgery than the TA technique.

Midazolam-flumazenil versus propofol anaesthesia for scoliosis surgery with wake-up tests.

BACKGROUND: Wake-up tests may be necessary during scoliosis surgery to ensure that spinal function remains intact. METHODS: Intra- and postoperative wake-up tests were performed together with somatosensory cortical evoked potentials (SCEPs) monitoring in 40 patients randomized to either midazolam (M) or propofol (P) infusions for scoliosis surgery. Other anaesthetic medication was similar in both groups. At the surgeon's request, N2O was turned off and midazolam or propofol infusions were discontinued. In the M group, flumazenil was given in refracted doses. Patients were asked to move hands and feet. The test was repeated immediately after the end of surgery. RESULTS: The median intraoperative wake-up times were 2.9 min in the M group and 16.0 min in the P group. The respective postoperative wake-up times were 1.8 and 13.9 min. The quality of both intra- and postoperative arousals was significantly better in the M group. Twelve patients in the P group could not be awakened intraoperatively within 15 min and were given naloxone. One of these patients woke up violently and dislodged the endotracheal tube. Another patient in the P group had explicit recall of the test, but no pain. Five patients in the M group became resedated in the recovery room. Cost of anaesthetic drugs was similar in both groups. Satisfactory intraoperative SCEPs were recorded from 17 patients in each group. There were no neurological sequelae. CONCLUSIONS: Wake-up tests can be conducted faster and better with midazolam-flumazenil sequence compared with propofol.

EMLA patch for spinal puncture. A comparison of EMLA patch with lignocaine infiltration and placebo patch.

We have prospectively assessed pain and anxiety of spinal puncture in 180 adult patients randomly allocated to one of three equal groups. On the morning of surgery group 1 had an EMLA patch, whereas group 2 and 3 had placebo patches. Group 2 also had infiltration analgesia with 2 ml lignocaine 2% with adrenaline, immediately before the block. Spinal anaesthesia was performed with 25 gauge sharp needles without introducer or 25,27 gauge blunt needles with 20,22 gauge introducers. Patients assessed the spinal puncture pain on a 10-cm visual analogue scale immediately after removal of the needle. Pain scores were significantly lower in group 1 (EMLA), median 0.75, than in group 2 (placebo, infiltration analgesia), median 1.75, and group 3 (placebo), median 1.80, p < 0.0001. Pain intensity was less than expected in more patients in the EMLA group than in the other two groups, p = 0.034. However, the decision to accept/reject spinal anaesthesia in the future was not influenced by the pain of lumbar puncture. We conclude that application of an EMLA patch is a simple and effective method to provide adequate analgesia for spinal puncture, which also helps to allay patients' fears of spinal anaesthesia.

Intra-arterial regional anaesthesia for hand surgery: a dose-finding study.

BACKGROUND: Intra-arterial regional anaesthesia (IARA) may be useful for ambulatory hand surgery in patients with poor veins. This randomized, double-blind study assessed which of the three doses of lignocaine gives the optimal analgesia with a minimum of adverse effects. METHODS: A preservative-free, alkalinized 0.5% lignocaine 1, 2 or 2.89 mg/kg body weight was injected into the radial arteries of 60 adult patients, allocated to three equal groups, to produce anaesthesia for carpal tunnel releases, capsulotomies, tenosynovectomies, palmar fasciectomies, Z-plastics, arthroplastics, arthrodeses etc. RESULTS: Surgical analgesia and motor block were best in group 3 (P < 0.01), whereas injection and tourniquet pain scores were similar in the three groups. Onset of analgesia was similar in all groups, and varied between 2 and 15 min. Cannulation time, surgery start time and tourniquet time were also similar in all groups, as were operating conditions and patient's acceptance of the method. No significant cardiovascular changes were observed after tourniquet release in any of the groups. Plasma lignocaine concentrations were lowest in group 1 (1 mg/kg) (P < 0.001). Five patients in group 1, seven in group 2 and seventeen in group 3 developed small bruises at the cannulation site (P < 0.001). Six patients (two in group 1, three in group 2 and one in group 3) had minor symptoms of lignocaine toxicity after tourniquet release (NS). No other complications were observed. CONCLUSIONS: The highest dose of lignocaine produces best surgical analgesia, without increasing the risk of toxicity. However, many patients receiving this dose will develop bruises at the injection site, and an occasional patient may need supplemental analgesia.