Femoral nerve block for pain relief in hip fracture: a dose finding study.

Hip fracture is the most common orthopaedic emergency. We investigated the concentration of 30 ml levobupivacaine that provided analgesia to 50% and 95% of patients with a hip fracture when injected around the femoral nerve under ultrasound guidance. We defined analgesia as a ≥ 20-point decrease on a 100-point pain scale with reduced cold sensation in the middle third of the anterior thigh 30 min after the nerve block. We increased the concentration of levobupivacaine if the preceding dose had been ineffective and decreased it if the preceding dose had been effective. Probit regression modelling estimated the effective (95% CI) concentration of 30 ml levobupivacaine in 50% and 95% of patients with a fractured hip to be 0.026 (0.023-0.028)% w/v and 0.036 (0.027-0.047)% w/v, respectively.

Transcutaneous carbon dioxide levels and oxygen saturation following caesarean section performed under spinal anaesthesia with intrathecal opioids.

BACKGROUND: Intrathecal opioids can be associated with respiratory depression which may have serious consequences. We describe the use of a non-invasive monitor (TOSCA) to measure transcutaneous carbon dioxide levels and percentage of haemoglobin oxygen saturation in post-caesarean section patients in two hospitals which used different intrathecal opioids. METHODS: Eighty-nine women undergoing caesarean section were monitored postoperatively until 08.00h on the first postoperative day. In addition to hyperbaric bupivacaine, patients from Hospital 1 received intrathecal diamorphine 300µg: those from Hospital 2 received intrathecal fentanyl 15µg and postoperative intramuscular morphine 10mg and were given morphine patient-controlled analgesia. Data from TOSCA were analysed the following day. Respiratory depression was defined as oxygen saturations <90% or transcutaneous carbon dioxide levels >7kPa for >2min or the need for medical intervention for clinical respiratory depression. RESULTS: Sustained hypercapnia was recorded in 8/45 (17.8%) patients from Hospital 1 and 3/44 (6.8%) from Hospital 2. Sustained oxygen saturations <90% were recorded in one patient from Hospital 2 and none from Hospital 1. The overall incidence of respiratory depression was 17.8% in Hospital 1 and 9.1% in Hospital 2. The median duration of hypercapnia was 9min [IQR 5.8-12.4] in Hospital 1 and 11.5min [IQR 7-32.8] in Hospital 2. No patient required medical intervention. CONCLUSIONS: The incidence of opioid-induced respiratory depression detected by TOSCA is higher than previously reported by other monitoring methods. TOSCA may have a role in detecting subclinical respiratory depression in the obstetric population. Further studies with a control population are needed.

Detection of herpes viruses in respiratory secretions of patients undergoing artificial ventilation.

The significance of detection of herpes viruses in respiratory secretions of critically ill patients is controversial. The study aim was to determine the prevalence of herpes virus DNA in respiratory secretions in patients on artificial ventilation. Respiratory secretions taken thrice weekly from 174 patients in a tertiary center intensive therapy unit (ITU) were tested for herpes simplex virus (HSV) by nested PCR. Samples from 61 patients in ITU for 4 days or more were also tested for Epstein Barr Virus (EBV) and cytomegalovirus (CMV) using real-time PCR. HSV positivity increased with ITU stay with 18.6% admission samples positive, 32.5% day 2-5 samples, and 65.9% day 6-39 samples. Being HSV positive on admission did not influence mortality (9/27, 33.3% vs. 38/118, 32.2%) however, subsequently, mortality of those negative but becoming positive was higher than in those remaining negative (10/35, 29% vs. 5/24 21%). At least one sample was EBV positive in 61% and CMV positive in 19% of patients tested. Of 63 patients tested for all three viruses, 4 were positive for three viruses, 23 patients for two viruses, 24 for one virus and 12 were negative for all the above viruses. Detection of HSV, EBV and CMV is common in ITU patients. Becoming HSV positive while in ITU may increase mortality.

Thrombosis associated with varicella zoster in an adult.

The incidence of varicella zoster in adults is increasing, and may be associated with a number of significant complications. An adult male presented with varicella zoster complicated by pneumonitis and thrombosis, leading to a below-knee amputation. Thrombosis with varicella zoster has been associated with vasculitis and free protein S deficiency. Other microthrombotic complications, such as purpura fulminans, are more common in children. Current treatment recommendations include acetaminophen (paracetamol) and lotions for symptomatic treatment. Intravenous acyclovir is recommended in the treatment of complicated varicella zoster, although it has not been shown to reduce the incidence of complications.

Determination of vancomycin in serum by liquid chromatography-high resolution full scan mass spectrometry.

A liquid chromatography-mass spectrometry (LC-MS) method was developed for the analysis of vancomycin (VCM) in human serum. The method was based on full scan data with extracted ions for the accurate masses of VCM and the atenolol internal standard obtained by Fourier transform MS. VCM was extracted from serum using strong cation exchange (SCX) solid phase extraction (SPE). The method was found to be linear in the range 0.05-10 microg/ml, which was adequate for quantification of VCM in serum samples, with a limit of quantification (LOQ) of 0.005 microg/ml and a limit of detection (LOD) of 0.001 microg/ml. Intra-day precision (n=5) was +/-3.5%, +/-2.5%, +/-0.7% at 0.05, 0.5 and 5 microg/ml, respectively. Inter-day precision (n=5) was +/-7.6%, +/-6.4%, +/-3.9% at 0.05, 0.5 and 5 microg/ml, respectively. The process efficiency for VCM was in the range 89.2-98.1% with the recovery for the atenolol internal standard (IS) being 97.3%. The method was used to determine VCM levels in patients during peri-operative infusion of the drug, which was found to result in drug levels within the required therapeutic window.

Observational study of perioperative PtcCO2 and SpO2 in non-ventilated patients receiving epidural infusion or patient-controlled analgesia using a single earlobe monitor (TOSCA).

BACKGROUND: TOSCA, a non-invasive monitor with a single earlobe probe incorporating a Stow-Severinghaus electrode and optical sensor (Linde Medical Sensors AG, Basel, Switzerland), has previously been used with ventilated patients and in sleep laboratories. We recorded transcutaneous carbon dioxide pressures (Ptc(co(2)) and oxygen saturations (Sp(o(2)) in non-ventilated patients to investigate opioid-induced respiratory depression. METHODS: This observational cohort study included 28 ASA I and II patients, monitored between 10 p.m. and 6 a.m., before and after elective major laparotomy. After operation, patients were kept on oxygen, 4 litre min(-1), and received either bupivacaine (0.1%) containing fentanyl (2 microg ml(-1) via epidural catheter (epidural analgesia group, EPI; n = 14) or morphine via patient-controlled analgesia infusion pump (PCA-morphine group, PCA; n = 14). RESULTS: The preoperative median (lower/upper quartile) Ptc(co(2)) was similar in both groups at around 5.5 kPa, but significantly higher after operation in PCA with 6.9 kPa (5.6/7.3) (P = 0.02), accompanied by a longer hypercarbia time >6 kPa of 6.6 h (0.1/8.0) (P = 0.04), and lower respiratory rates of 13.9 breaths min(-1) (13.3/15.4) (P = 0.04). In EPI, the corresponding results were 5.8 kPa (5.5/6.0), 1.2 h (0.1/4.3), and 16.2 breaths min(-1) (14.8/16.7). The perioperative median Sp(o(2)) in both groups was comparable within the normal range, although generally higher when on supplemental oxygen (P = 0.26). The Sp(o(2)) time <94% was similar in both groups (P = 0.33) as were pain scores (P = 0.25). CONCLUSIONS: Ptc(co(2)) recording in patients on PCA-morphine and supplemental oxygen revealed hypercapnia in the presence of normal respiratory rates and Sp(o(2)) values. This is recommended as an easy and sensitive monitor of respiratory depression and may have a role in the safe administration of opioid-analgesia.

Intravenous amiodarone in intensive care. Time for a reappraisal?

Amiodarone is widely used in intensive care units for the treatment of a variety of arrhythmias. It is currently the drug of choice for supraventricular tachyarrhythmias in many units because of its combination of efficacy and safety. This review summarises the current state of knowledge regarding the short-term administration of intravenous amiodarone to control arrhythmias in perioperative, coronary care and intensive care patients. It outlines the electrophysiology, haemodynamics, pharmacokinetics and toxicity of the drug. In particular, it examines the recent concerns regarding acute pulmonary toxicity.

Epidural analgesia in Scotland: a survey of extradural opioid practice.

A postal survey of all Consultant Anaesthetists working within Scotland was conducted to establish the current state of epidural analgesia and the level of post-operative care for patients after epidural opioid administration. Of those consultants using epidurals for post-operative analgesia, 89% use extradural opioids, and the lipid soluble opioids diamorphine and fentanyl by an infusion technique were the most popular. For analgesia in labour the use of extradural opioids drops to 41% with fentanyl by bolus the commonest drug and method of administration. Monitoring requirements after extradural opioids are variable with more than half of consultants satisfied with intermittent observational measurements. Sixty-nine per cent of consultants frequently send their patients to a high dependency unit following epidural opioid administration. Additional administration of opioids on an ordinary ward setting is considered inappropriate by over half of the consultants replying. There is considerable variability amongst anaesthetists as to how patients receiving epidural opioids should be monitored and National Recommendations are required to stop the present confusion.

The effect of parenteral diclofenac and morphine on duration and height of blockade of continuous epidural infusion of bupivacaine 0.5%.

Twenty-six patients undergoing abdominal hysterectomy (ASA 1-2) were entered into a double-blind randomised trial to determine: (a) whether diclofenac given intravenously could influence the effective duration of a continuous epidural infusion of bupivacaine 0.5%, and (b) whether morphine given intravenously altered the height of the regressing block. A block to T4 was established pre-operatively and a continuous infusion of 0.5% bupivacaine 8 ml.h-1 ran for 14 h. Thirteen patients received 50 mg diclofenac intramuscularly before surgery repeated at 4 and 10 h later and 13 patients received saline intramuscularly. The height of blockade and pain scores were measured hourly. Effective block duration was defined as regression to T10 or lower and/or a pain score of 2 or more. At this point 10 mg of morphine was given intravenously and the height of the block reassessed. Duration of blockade was not significantly prolonged (p > 0.05), but pain scores were significantly reduced with diclofenac (p < 0.01). Morphine did not alter blockade height. It is concluded that epidural bupivacaine and diclofenac act additively on postoperative pain.

The conjugation of phenols with phosphate in grass grubs and flies.

1. Houseflies, blowflies and New Zealand grass grubs were dosed with 1-naphthol, 2-naphthol or p-nitrophenol. 2. The corresponding monoaryl phosphates were identified in extracts of insects or excreta along with the beta-glucosides and ethereal sulphates of the phenols. 3. No diaryl phosphates or glucosiduronates were detected but an unidentified metabolite of [(14)C]1-naphthol was present in extracts of flies dosed with [(14)C]1-naphthol.