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Biomedical subjects

I H Wilson

Publications and source records attributed to I H Wilson.

At least 19 recordsLinked to original sources

Anaesthesia services in developing countries: defining the problems.

We describe the use of a questionnaire to define the difficulties in providing anaesthesia in Uganda. The results show that 23% of anaesthetists have the facilities to deliver safe anaesthesia to an adult, 13% to deliver safe anaesthesia to a child and 6% to deliver safe anaesthesia for a Caesarean section. The questionnaire identified shortages of personnel, drugs, equipment and training that have not been quantified or accurately described before. The method used provides an easy and effective way to gain essential data for any country or national anaesthesia society wishing to investigate anaesthesia services in its hospitals. Solutions require improvements in local management, finance and logistics, and action to ensure that the importance of anaesthesia within acute sector healthcare is fully recognised. Major investment in terms of personnel and equipment is required to modernise and improve the safety of anaesthesia for patients in Uganda.

Adult↗

Epidural infusion or combined femoral and sciatic nerve blocks as perioperative analgesia for knee arthroplasty.

BACKGROUND: Peripheral neural blockade appears to provide effective analgesia with potentially less morbidity than central neuraxial techniques. We compared the relative benefits of combined femoral (3-in-1) and sciatic nerve block with epidural blockade for postoperative knee arthroplasty analgesia. METHODS: Sixty patients, ASA I-III, undergoing unilateral knee replacement were prospectively randomized to receive either a lumbar epidural infusion or combined single-shot femoral (3-in-1) and sciatic blocks (combined blocks). All patients received standard general anaesthesia. Visual analogue pain scores and rescue opioid requirements were recorded at four time points postoperatively. Patient satisfaction, morbidity, block insertion time, perioperative blood loss and rehabilitation indices were also assessed. RESULTS: In both groups, pain on movement was well controlled at discharge from recovery and 6 h postoperatively but increased at 24 and 48 h. Median (95% CI) analogue scale scores were 0 (0-0), 15 (0-30), 55 (38-75) and 54 (30-67) mm for epidural block and 0.5 (0-22), 21.5 (10-28), 40 (20-50) and 34.5 (21-55) mm for combined block. VAS pain scores with the combined blocks were significantly lower at 24 h (P=0.004). Total morphine usage was low in both groups: median epidural group 17 mg (8-32) versus combined blocks 13 mg (7.8-27.5). Patient satisfaction was high in both groups with median (95% CI) scores of 100 (85-100), 83 (70-100) and 82 (57-90) mm for epidural and 90 (73-100), 100 (77-100) and 97 (80-100) mm for combined blocks (not significant). Perioperative blood loss and rehabilitation indices were also similar. CONCLUSIONS: Combined femoral (3-in-1) and sciatic blocks offer a practical alternative to epidural analgesia for unilateral knee replacements.

Aged↗

The use of the laryngeal mask airway and Combitube in cardiopulmonary resuscitation; a national survey.

The laryngeal mask airway (LMA) and Combitube have been recommended for use during cardiopulmonary resuscitation (CPR). An overview of current practice was sought by conducting a postal survey of 265 Resuscitation Training Departments, at different hospitals, throughout the UK. One hundred fifty-three (58%) completed questionnaires were returned. Only 38 (25%) hospitals which replied were currently using the LMA in resuscitation while seven (5%) were using the Combitube. The reasons for not using these airway adjuvants included concerns about airway protection, difficulties in training, cost, and the concept that when anaesthetists were available on cardiac arrest teams these devices were unnecessary.

Cardiopulmonary Resuscitation↗

Comparison of articaine and bupivacaine/lidocaine for peribulbar anaesthesia by inferotemporal injection.

BACKGROUND: Articaine is a novel amide local anaesthetic with a shorter duration of action than prilocaine. METHODS: In a randomized, double-blind study we compared the efficacy of 2% articaine with epinephrine 1:200,000 with a mixture of 0.5% bupivacaine and 2% lidocaine with epinephrine 1:200,000 for peribulbar anaesthesia in cataract surgery using a single inferotemporal injection. Eighty-two patients were randomly allocated to one of two groups to receive peribulbar anaesthesia with 6-7 ml of articaine or a bupivacaine/lidocaine mixture. Both solutions contained hyaluronidase 30 iu ml(-1). Ocular movement was scored at 2 min intervals up to 10 min, at the end of surgery and at time of discharge from hospital. Time to readiness for surgery and any complications (proptosis, chemosis, pain) were recorded. RESULTS: The articaine group demonstrated a rapid onset of peribulbar block with mean time (SD) to readiness for surgery of 4.2 (4.5) min compared with 7.2 (5.7) min in the bupivacaine/lidocaine group (P=0.0095). The block obtained in the articaine group was dense with eye movement scores at 2, 4, 6, 8 and 10 min all significantly reduced (P<0.01 at each interval). There was also a faster offset of the block in the articaine group (P=0.0009). There was no difference in incidence of minor complications between the groups. CONCLUSIONS: Two per cent articaine is safe and effective for peribulbar anaesthesia by inferotemporal injection and is a suitable alternative to the traditional mixture of 0.5% bupivacaine and 2% lidocaine.

Aged↗

Variable-temperature scanning tunneling microscopy and scanning tunneling spectroscopy study on copper phthalocyanine ultrathin films on a Au(111) surface.

Variable-temperature high-resolution scanning tunneling microscopy (STM) images reveal that well-ordered copper phthalocyanine (CuPc) strips can be self-assembled by depositing CuPc molecules on a Au(111) surface. The self-assembled strips are supposed to result from the balance of the intermolecular interaction and the interaction between the molecules and substrate during annealing. The energy band (approximately 1.9-2.1 eV) of CuPc, measured by scanning tunneling spectroscopy (STS), is comparable to the optical band gap (approximately 1.7 eV). Spectroscopic measurements confirm that a dipole layer and/or an effect of image force exist at the CuPc/Au(111) interface.

Crystallization↗

Comparison of articaine and bupivacaine/lidocaine for single medial canthus peribulbar anaesthesia.

In a single-centre, randomized, double-blind study, we compared the efficacy of 2% articaine with that of a mixture of 0.5% bupivacaine and 2% lidocaine for peribulbar anaesthesia in cataract surgery, using a single medial canthus injection technique. Eighty-two patients were allocated randomly to receive 7-9 ml of a mixture of 0.5% bupivacaine and 2% lidocaine or an equal volume of 2% articaine with 1:200,000 epinephrine. Hyaluronidase 30 iu ml(-1) was added to both solutions. The degree of akinesia was scored 1, 5 and 10 min after the block, at the end of surgery and at discharge from the day case unit. Primary outcome measures were the difference in ocular movement scores 5 min after block and the need for supplementary inferolateral injections. There was greater akinesia in the articaine group at 5 min (P=0.01). Ten patients (24%) in the articaine group and 21 patients (51%) in the bupivacaine/lidocaine group required a supplementary injection (P=0.02). The mean (SD) volume of local anaesthetic required to achieve adequate block for surgery was 9.7 (2.1) ml in the articaine group and 11.0 (2.2) ml in the bupivacaine/lidocaine group (P=0.01). There was a faster offset of akinesia after surgery in the articaine group (P=0.01). There were no differences between groups in the incidence of reported pain or of minor complications. In our study, 2% articaine with 1:200,000 epinephrine was safe and efficacious for single medial canthus peribulbar anaesthesia.

Aged↗

Bronchopleural fistula complicating group A beta-haemolytic streptococcal pneumonia. Use of a Fogarty embolectomy catheter for selective bronchial blockade.

A 36-year-old woman developed severe group A Streptococcal pneumonia, complicated by a bronchopleural fistula, ARDS and multi-organ failure. We describe the use of selective middle lobe bronchus blockade, with a Fogarty embolectomy catheter, to localise and control the air leak. This allowed effective mechanical ventilation and oxygenation on intensive care and during right middle lobectomy. The patient made a prolonged, but full recovery.

Adult↗

Drawover vaporizers for sedation in intensive care.

OBJECTIVE: We have undertaken a laboratory study to determine whether a drawover vaporizer in the inspiratory limb of an intensive care ventilator circuit can produce safe and therapeutic concentrations of isoflurane. DESIGN: An Oxford Miniature Vaporizer (OMV) and Ohmeda TEC vaporizer were assessed over the range of inspired isoflurane concentrations, airway pressures and tidal volumes experienced in the ICU. CONCLUSIONS: The experimental findings suggest that the OMV inhaler in plenum mode can be relied upon to produce safe concentrations of isoflurane over a clinically useful range of inspired concentrations. Furthermore, it behaves predictably over the range of airway pressures likely to be encountered in the patient admitted with acute severe asthma. However, we found that the Ohmeda TEC vaporizer did not perform reliably in this setting.

Anesthetics, Inhalation↗

Knowledge about pulse oximetry among medical and nursing staff.

Although pulse oximeters are increasingly used to monitor patients on medical and surgical wards, staff seem to receive no specific training in the operation of these devices. We investigated the knowledge of junior doctors and nursing staff about pulse oximetry as used on seriously ill patients in a District General Hospital in Exeter, UK. 30 medical or surgical preregistration house officers or senior house officers and 30 staff nurses answered a structured questionnaire. Questions were asked about the theory behind pulse oximetry, factors affecting readings, "normal" values in various patients, values in hypothetical clinical situations, and what training subjects had received. Responses were scored against standard answers from reference texts. 97% of doctors and nurses did not understand how a pulse oximeter worked and were confused about factors influencing readings. Respondents gave a wide range of acceptable saturation values (eg, 90-100% for a fit adult), thus demonstrating poor understanding of physiological principles. There were serious errors made in evaluating saturation readings in hypothetical clinical situations. Only 1 doctor had received formal training in the use of pulse oximetry. Our survey revealed that junior doctors and staff nurses were untrained in pulse oximetry, lacked knowledge of basic principles, and made serious errors in interpretation of readings. Training is needed for staff who use pulse oximeters.

Adult↗

Effect of humidification on inhalation induction with isoflurane.

Forty-two patients undergoing inhalation induction with isoflurane in nitrous oxide and oxygen, were allocated randomly to receive either humidified or non-humidified gas. Humidification resulted in a significantly lower incidence of problems during induction (P less than 0.05).

Adolescent↗

Analgesia following extradural and i.m. pethidine in post-caesarean section patients.

The onset, quality and duration of analgesia following extradural pethidine 50 mg and i.m. pethidine 100 mg was assessed in 30 postoperative patients who had undergone Caesarean section under extradural anaesthesia. Saline and pethidine were given in a randomized, double-blind fashion using simultaneous extradural and i.m. injections. Extradural pethidine provided superior analgesia, of quicker onset but similar duration, and both treatments were associated with a low incidence of side effects.

Analgesia, Epidural↗

Domiciliary oxygen concentrators in anaesthesia: preoxygenation techniques and inspired oxygen concentrations.

A conventional preoxygenation technique was compared in two volunteers with two techniques based on a drawover breathing system supplied with oxygen enriched air from a Devilbiss Mini VO2 domiciliary oxygen concentrator. Breathing from a 20-litre bag, filled previously at 2 litre min-1 from the concentrator was as effective as the conventional technique (PaO2 73.2 kPa). Supplying 4 litre min-1 to a drawover system was less effective (PaO2 35.5 kPa). We present a simple method for determining the inspired oxygen concentration obtained under conditions of drawover anaesthesia using an oxygen concentrator.

Anesthesia, General↗

Central venous pressure monitoring for the critically ill in Zambia.

The safety and value of central venous pressure (CVP) monitoring in 100 critically ill patients in Zambia was studied prospectively. There were six complications related to insertion, the only serious one being a hydrothorax which was recognized and treated. One patient developed catheter-related septicaemia. CVP measurement altered proposed fluid management in 19 cases, determined management in 31 in whom fluid status was uncertain and confirmed fluid therapy in 50. Additional benefits of central venous catheterization were drug infusion in 33 patients and venous access in 53. Technical problems during monitoring occurred in 54 cases and were due to kinking of the catheter, blockage or inadvertent removal. In our circumstances the risks of cannulation of central veins seem justified in selected patients but good nursing supervision of patients is necessary.

Adolescent↗