Nitric oxide synthase isoforms play distinct roles during acute peritonitis

Background. Acute peritonitis is the most frequent complication of peritoneal dialysis (PD). Increased nitric oxide (NO) release by NO synthase (NOS) isoforms has been implicated in acute peritonitis, but the role played by the NOS isoforms expressed in the peritoneum is unknown

Failed epidural: causes and management

Failed epidural anaesthesia or analgesia is more frequent than generally recognized. We review the factors known to influence the success rate of epidural anaesthesia. Reasons for an inadequate epidural block include incorrect primary placement, secondary migration of a catheter after correct placement, and suboptimal dosing of local anaesthetic drugs. For catheter placement, the loss of resistance using saline has become the most widely used method. Patient positioning, the use of a midline or paramedian approach, and the method used for catheter fixation can all influence the success rate. When using equipotent doses, the difference in clinical effect between bupivacaine and the newer isoforms levobupivacaine and ropivacaine appears minimal. With continuous infusion, dose is the primary determinant of epidural anaesthesia quality, with volume and concentration playing a lesser role. Addition of adjuvants, especially opioids and epinephrine, may substantially increase the success rate of epidural analgesia. Adjuvant opioids may have a spinal or supraspinal action. The use of patient-controlled epidural analgesia with background infusion appears to be the best method for postoperative analgesi

Molecular mechanisms of action of systemic lidocaine in acute and chronic pain: a narrative review

Systemic administration of the local anaesthetic lidocaine is antinociceptive in both acute and chronic pain states, especially in acute postoperative and chronic neuropathic pain. These effects cannot be explained by its voltage-gated sodium channel blocking properties alone, but the responsible mechanisms are still elusive. This narrative review focuses on available experimental evidence of the molecular mechanisms by which systemic lidocaine exerts its clinically documented analgesic effects. These include effects on the peripheral nervous system and CNS, where lidocaine acts via silencing ectopic discharges, suppression of inflammatory processes, and modulation of inhibitory and excitatory neurotransmission. We highlight promising objectives for future research to further unravel these antinociceptive mechanisms, which subsequently may facilitate the development of new analgesic strategies and therapies for acute and chronic pain

Influence of arm position on ultrasound visibility of the axillary brachial plexus

BACKGROUND Contemporary axillary brachial plexus block is performed by separate injections targeting radial, median, ulnar and musculocutaneous nerve. These nerves are arranged around the axillary artery, making ultrasound visualisation sometimes challenging. In particular, the radial nerve can be difficult to localise deep to the artery. OBJECTIVES The primary aim of this study was to investigate which arm position optimises the visibility of the radial nerve. Secondary aims were the visibility and position of the other nerves during varying arm positions. DESIGN A prospective observational study. SETTING University teaching hospital, November 2012. PARTICIPANTS Twenty volunteers, recruited by an advertisement on the Department's bulletin board. Inclusion criterion age more than 18 years. Exclusion criteria: refusal of ultrasound examination, restricted shoulder movement, local infection, BMI greater than 30 kgm(-2). INTERVENTION One anaesthesiologist performed bilateral ultrasound examinations of the axillary brachial plexus on 20 volunteers. Each arm was placed in different positions [shoulder (S) 90 degrees or 180 degrees abduction, elbow (E) 0 degrees or 90 degrees extension] and scans were performed proximally in the axilla, and additionally 5cm distally to this point [proximal (P) vs. distal (D)], resulting in eight different scans stored for off-line analysis performed by two blinded anaesthesiologists. MAIN OUTCOME MEASURES For radial, median, ulnar and musculocutaneous nerve, visibility was assessed on a sixpoint visibility scale. Distances and angles of the nerves relative to the axillary artery and distances relative to the skin were measured. RESULTS No significant differences between arm positions were found in the visibility score of radial (P = 0.359) and musculocutaneous nerves (P = 0.073). Visibility of the median nerve was improved in positions S90 degrees/E0 degrees/D and S180 degrees/E0 degrees/P (P = 0.02). The ulnar nerve was more visible in position S180 degrees/E 0 degrees/P and D (P = 0.007). The greatest distance between artery and radial nerve was 7.4 +/- 4.7mm at an angle of 120 +/- 14 degrees in position S180 degrees/E 0 degrees/D. CONCLUSION The visibility of the radial nerve was not improved by varying positions of the arm. S180 degrees/E0 degrees provided the best overall visibility and accessibility of nerve

Management of the patient with diabetic peripheral neuropathy presenting for peripheral regional anesthesia: a European survey and review of literature

Diabetic peripheral neuropathy (DPN) is a frequent complication of longstanding diabetes mellitus. There is no evidence-based consensus whether neuropathic patients undergoing peripheral regional anesthesia are at increased risk of neurologic damage. It is unknown whether these controversial results have been incorporated into clinical practice. We conducted a survey to test the hypothesis that the majority of respondents would consider DPN a potential risk factor for nerve damage in regional anesthesia, and would adapt their technique when performing regional anesthesia. In parallel, we sought to summarize the current knowledge-base regarding regional anesthesia and DPN. We therefore performed 1) a literature search to review current literature and 2) an online computer-based survey among members of the European Society of Regional Anesthesia and Pain Therapy (ESRA). The overall response rate was 19% (584 responders/3107 invitations). About a quarter of participants would avoid regional anesthesia in patients with diabetic neuropathy, and 59% of respondents would counsel patients with diabetic neuropathy about increased risk of regional anesthesia. When techniques were modified, most participants would decrease or omit epinephrine, while fewer respondents would decrease dose of local anesthetic or perform other adjustments. More than 80% agreed with the statement that nerve blocks could be performed safely in diabetic neuropathic patients. In conclusion, we report the results of the first survey analyzing attitudes and standards of care among European anesthesiologists with regards to regional anesthesia in DPN. While literature is divided on the question whether pre-existing diabetic neuropathy is a risk factor for new neurological deficit after regional anesthesia, most of the responders of this survey take measures to reduce risks, counsel patients on a possible greater risk of neurologic complications, but only a minority of responders would avoid peripheral regional anesthesia altogethe

Sevoflurane in exhaled air of operating room personnel

Evidence on potential health hazards arising from exposure to volatile anesthetics remains controversial. Exposure may, in principle, be supervised by monitoring of ambient air or, alternatively, in vivo. We used the Proton Transfer Reaction-Mass Spectrometry to screen the breath of 40 operating room staff members before operating room duty, 0, 1, 2, and 3 h after duty, and before commencing duty on the consecutive day, and control persons. Staff members exhibited significantly increased sevoflurane levels in exhaled air after duty, with a mean of 0.80 parts per billion as compared with baseline values of 0.26 parts per billion (P <0.05). Analysis of variance with adjustment for within correlation (repeated measurements) showed a statistically significant time-effect (P <0.001). We conclude that (a) Proton Transfer Reaction-Mass Spectrometry biomonitoring of exhaled sevoflurane can serve as a simple and rapid method to determine volatile anesthetic excretion after occupational exposure, and (b) significant concentrations of sevoflurane may be continuously present in persons exposed to sevoflurane on a daily basis. IMPLICATIONS: The present study depicts the profile of volatile anesthetics, isoflurane and sevoflurane, in exhaled air of ambulatory patients. Biomonitoring of expired anesthetic concentrations is a noninvasive and rapid method to determine volatile anesthetic excretio