Epidural abscess complicating insertion of epidural catheters

Editor—We read with interest the case reports on epiduralabscesses by Phillips and colleagues¹ as well as the relatedcorrespondence from Hearn.² In total, 6143 epidurals have beenperformed in the University Hospitals of Leicester between February1994 and August 2001. During this period there have been sixepidural abscesses reported from two hospitals in the trust.This is an incidence of 0.1%, which is very close to the incidencereported by Phillips of 0.125%.¹ The incidence reported elsewherevaries between 0.01% and 0.05%, but our results suggest a significantlyhigher rate.^3–5 One patient was a 57-yr-old male who was admitted for an IvorLewis oesophagectomy for adenocarcinoma of the gastro-oesophagealjunction. His past medical history included bronchiectasis.He was admitted 5 days before surgery for optimization withbronchodilators and regular physiotherapy. Surgery was performedunder general anaesthesia with an epidural sited at T7/8, requiring     

Incidence of adrenal insufficiency after severe traumatic brain injury varies according to definition used: clinical implications

Background. Adrenal insufficiency impacts on the haemodynamicmanagement of patients in intensive care. Very little is knownabout the incidence of adrenal insufficiency in the first 10days after traumatic brain injury. Methods. We retrospectively reviewed the charts of 113 traumaticbrain injury patients within 10 days of their injury. They allhad a high-dose corticotropin stimulation test performed becauseof haemodynamic instability. Blood cortisol concentrations weremeasured at baseline, 30 and 60 min after the administrationof high-dose corticotropin. The incidence of adrenal insufficiencywas determined according to various definitions used in theliterature. Results. The baseline cortisol concentration was <414 nmollitre^–1 (15 µg dl^–1) in 78% of patients and<690 nmol litre^–1 (25 µg dl^–1) in all patients.The cortisol concentration did not rise above 500 nmol litre^–1(18 µg dl^–1) at 30 and 60 min in 49 and 22% of patients,respectively. The cortisol concentration did not rise by 250nmol litre^–1 (9 µg dl^–1) at 30 and 60 minin 48 and 25% of patients respectively. Primary adrenal insufficiencydefined by an abnormal baseline cortisol concentration and anabnormal response to the high-dose corticotropin stimulationtest was present in 13–28% of patients according to thecut-off values used. Conclusions. The incidence of adrenal insufficiency varies from25 to 100% in the first 10 days after traumatic brain injury.The range of incidences reported illustrates the need for standardizationof the definition of adrenal insufficiency. This has a directimpact on treatment. Sampling at 60 min after the high-dosecorticotropin stimulation test seems to correlate better withthe maximum secreting capacity of the adrenal glands.      

Does low-volume inter-scalene block attenuate the severity of diaphragmatic paresis?

Editor—I commend Riazi and colleagues¹ on their importantstudy demonstrating that the analgesic effect of an interscalenebrachial plexus block (ISBPB) may be achieved with an extremelylow volume (5 ml) of local anaesthetic, while simultaneouslyreducing the incidence of phrenic nerve palsy (from 100% to     

Diathermy does not reduce subconjunctival haemorrhage during sub-Tenon's block

Editor—The frequency of subconjunctival haemorrhage duringposterior sub-Tenon's block is 7–56%.^{1 2} This is usuallyconfined to the area of dissection but can spread to other quadrants.²The incidence is even higher with the use of an anterior sub-Tenon'scannula.³ The damage to fine vessels inevitably severed duringconjunctival dissection is the     

Anaesthesia-related diplopia after cataract surgery

Editor—We were interested in Gomez-Arnau and colleagues’¹paper, which reported incidences of anaesthesia-related diplopiaof 0.39 and 1% following 2024 retrobulbar and 98 peribulbarblocks. Nineteen anaesthetists had performed these blocks duringa 3 yr period. Our own retrospective audit of 940 consecutiveperibulbar blocks for cataract surgery, performed personallyor directly supervised by four anaesthetists between June 1999and June 2000, found six cases of persistent postoperative verticaldiplopia—an incidence of 0.64%.² All our patients with diplopia showed an immediate postoperativehypertropia in the injected eye, and evidence of muscle weakness,which changed over the subsequent 4–6 weeks to hypotropiawith restricted elevation of the affected eye. This suggeststhat the inferior rectus was the affected muscle. All the     

Diamorphine-bupivacaine mixture compared with plain bupivacaine for analgesia

We have studied the efficacy of two extradural infusions (10ml h^–1 in 50 patients in active labour. Patients in thediamorphine group (n = 25) received 0.0625% plain bupivacaine6.25 mg h^–1 mixed with 0.005% diamorphine 0.5mg h^–1and those in the control group (n = 25) received 0.125% plainbupivacaine 12.5 mg h^–1. Both groups received intermittent"top-ups" of 0.25% bupivacaine 10 ml when indicated. Althoughmedian pain scores during the infusion were similar in bothgroups, patients in the diamorphine group indicated greatersatisfaction with the infusion (88% very satisfied, comparedwith 52% in the control group (P < 0.02)). There were nodifferences in the incidence of hypotension, instrumental vaginaldelivery, number of "top-ups", duration of the second stageor extent of motor block. However, patients in the diamorphinegroup had a high incidence of pruritus (44%, compared with 0%in the control group (P < 0.01)). (Br. J. Anaesth. 1994;72:58–61) Presented in part at the European Society of Anaes-thesiologistsFounding Congress, Brussels, May 1993.     

Effect of adding dopexamine to intraoperative volume expansion in patients undergoing major elective abdominal surgery

Background. The contribution of low-dose dopexamine to outcome,when given to increase cardiac output in patients already treatedwith fluids during major abdominal surgery, is not yet known. Method. We carried out a randomized double-blind placebo-controlledtrial. All 100 patients studied were given fluid infusions duringsurgery guided by stroke volume measurements made with an oesophagealDoppler probe. Patients were randomized to receive dopexamineat the rate of 0.25 µg kg^–1 min^–1or saline 0.9% (control) for the first 24 h after the startof surgery. The primary outcome measure was the incidence ofpostoperative morbidity. Results. There were no statistically significant differencesbetween groups in the incidence of postoperative complications,the length of hospital stay, the incidence of morbidity andthe use of critical care facilities. The patients randomizedto receive dopexamine had significantly more pre-existing diseasethan the control patients. Mortality in both groups was significantlyless than predicted by the POSSUM (Physiological and OperativeSeverity Score for the enUmeration of Mortality and morbidity)risk prediction score. Conclusion. We could not demonstrate an advantage to using low-dosedopexamine in high-risk patients during major abdominal surgery. Br J Anaesth 2003; 91: 619–24     

Safe placement of central venous catheters

Editor—We read with interest the recent paper on centralvenous catheter (CVC) tip position using the carina as a radiologicallandmark¹ having recently completed a similar retrospectiveaudit of 139 CVCs in an adult intensive care setting. Similarto Stonelake and Bodenham, we found a high incidence of CVCtips below the carina with 50 (35.9%) right-sided and 8 (5.7%)left-sided so placed. Similarly, more than half of the left-sidedcatheters that were above the carina had     

Reliable detection of epidural haematomas

Editor—We thank Dr Meikle and colleagues for their informativearticle on the detection and management of epidural haematomas¹and we agree with the suggestion in the allied editorial² thatthe true incidence of haematomas is much higher than one every2 yr in the UK. At our institution, we have a high rate of electiveepidural insertion and in the last 6 months there have beentwo cases that highlight the difficulties in this area of practice.First, a patient developed an epidural haematoma which remainedundetected for more than 24 h, and was     

Effect of intraoperative intravenous crystalloid infusion on postoperative nausea and vomiting after gynaecological laparoscopy: comparison of 30 and 10 ml kg(-1)

Background. I.V. fluid administration has been shown to reducepostoperative nausea and vomiting (PONV). The optimum dose isunknown. We tested the hypothesis that administration of i.v.crystalloid of 30 ml kg^–1 would reduce the incidence ofPONV compared with 10 ml kg^–1 of the same fluid. Methods. A total of 141 ASA I female patients undergoing electivegynaecological laparoscopy were randomized, in double-blindfashion, to receive either 10 ml kg^–1 (n=71; CSL-10 group)or 30 ml kg^–1 (n=70; CSL-30 group) of i.v. compound sodiumlactate (CSL). Results. In the first 48 h after anaesthesia, the incidenceof vomiting was lower in the CSL-30 group than in the CSL-10group (8.6% vs 25.7%, P=0.01). Anti-emetic use was less in theCSL-30 group at 0.5 h (2.9% vs 14.3%, P=0.04). The incidenceof severe nausea was significantly reduced in the treatmentgroup at awakening (2.9% vs 15.7%, P=0.02), 2 h (0.0% vs 8.6%,P=0.04) and cumulatively (5.7% vs 27.1%, P=0.001). The numbersneeded to treat to prevent vomiting, severe nausea and antiemeticuse in the first 48 h were 6, 5 and 6, respectively. Conclusion. I.V. administration of CSL 30 ml kg^–1 to healthywomen undergoing day-case gynaecological laparoscopy reducedthe incidence of vomiting, nausea and anti-emetic use when comparedwith CSL 10 ml kg^–1.     

Comparison of the analgesic and emetic properties of ketorolac and morphine for paediatric outpatient strabismus surgery

In a prospective, double-blind, randomized study, we have comparedi.v. ketorolac and morphine in paediatric outpatients undergoingstrabismus surgery. Forty-two ASA I or II children, aged 2–12yr, were allocated randomly to receive either ketorolac 0.75mgkg^–1 i.v. or morphine 0.1 mg kg^–1i.v. and metoclopramide0.15 mg kg^–1. Anaesthesia was induced with propofol andmaintained with propofol and nitrous oxide. Pain was assessedat 15-min intervals until discharge, and the incidence of nauseaand vomiting was recorded for the first 24 h. There was no differencein pain behaviour scores or recovery times. The incidence ofnausea and vomiting during the first 24 h was 19%in the ketorolacgroup and 71%in the morphine group (P<0.001). We concludedthat ketorolac was an effective analgesic for this type of surgeryand that it was associated with less postoperative emesis thanmorphine and metoclopramide.     

A prospective, double-blind, randomized trial of caudal block using ropivacaine 0.2% with or without fentanyl 1 microg kg-1 in children

Background. It has been reported that ropivacaine produces vasoconstrictionin contrast to vasodilation produced by bupivacaine. It is possiblethat additives to ropivacaine can provide further analgesicadvantages compared with bupivacaine. We thus evaluated whetherthe addition of fentanyl to ropivacaine prolonged the durationof analgesia after a single shot caudal block. Methods. A total of 36 children undergoing surgical proceduresbelow the umbilicus were randomly allocated to one of two groups:Group F received ropivacaine 0.2%, 1 ml kg^–1 with fentanyl1 µg kg^–1 and Group S received ropivacaine 0.2%,1 ml kg^–1 with saline. The analgesic effect of the caudalblock was evaluated using the Children's Hospital of EasternOntario Pain Scale (CHEOPS) and sedation was assessed usingthe Steward score at 30 min after extubation and at 1, 2, 4,6, 12 and 24 h. The first analgesic requirement time and side-effectsin a 24 h period were also recorded. Results. There were no differences in characteristics betweenthe groups. The end-tidal concentration of sevoflurane at extubationin Group F was significantly lower than in Group S. However,there was no significant difference in time from discontinuationof the volatile anaesthetics to tracheal extubation. No statisticaldifferences were found in the CHEOPS and Steward score, andthe time to first analgesia. The incidence of postoperativevomiting was not significantly different. Conclusion. We found that the addition of fentanyl 1 µgkg^–1 to ropivacaine 0.2% for caudal analgesia providesno further analgesic advantages over ropivacaine 0.2% alone.     

Thrombocytosis in intensive care

We conducted a retrospective study of platelet count in 226patients admitted for critical care over a 5-month period, toexplore the incidence of thrombocytosis and its relation toadmission category, duration of ICU stay and outcome. Our findingsindicate that thrombocytosis is not rare in ICU patients. Atleast one platelet count greater than 450x10⁹ litre^–1was found in 21.7% of patients and was associated with lowerICU mortality (P=0.003), lower hospital mortality (P=0.006),but longer duration of ICU stay (P<0.0001). Thrombocytosismay serve as an independent predictor of favourable outcomein ICU patients. Br J Anaesth 2001; 87: 926–8     

Contrast-induced nephropathy

Interventional radiological procedures involving anaesthesiaare generally increasing. Contrast-induced nephropathy (CIN),usually defined as an increase in serum creatinine of 44 µmollitre^–1 (0.5 mg dl^–1) or a 25% increase from thebaseline value 48 h after intravascular injection of contrastmedia, is a common and potentially serious complication of theuse of iodinated contrast media in patients at risk of acuterenal injury. It is an important cause of hospital-acquiredrenal failure, may be a difficult differential diagnosis andthe incidence does not appear to have changed over the lastfew decades. In the general population, the incidence of CINis estimated to be 1–2%. However, the risk for developingCIN may be as high as 50% in some patient subgroups, such asthose with diabetes mellitus and pre-existing renal impairment.The impact of CIN on clinical outcomes has been evaluated mostextensively in patients undergoing percutaneous coronary interventionwhere it is associated with increased mortality both in hospitaland at 1 yr. As treatment is limited to supportive measureswhile awaiting the resolution of the renal impairment, emphasisneeds to be directed at prevention.     

Intravenous opioids reduce airway irritation during induction of anaesthesia with desflurane in adults

Desflurane is not used for the induction of anaesthesia despiteits favourable pharmacokinetic characteristics because it causesairway irritation. We investigated whether pretreatment withi.v. narcotics reduced unwanted effects. One hundred and eightyadults were randomized to three groups (60 per group) to receivei.v. saline, fentanyl 1 µg kg^–1 and morphine0.1 mg kg^–1, respectively, before inhalationalinduction with desflurane in nitrous oxide and oxygen. Meantime to loss of response to commands was 4.0 min, withoutsignificant differences between groups. The incidence of coughingwas greater (25%) in the control group than in the fentanyl(5.0%) and morphine groups (8.3%). The incidence of apnoea was20.0% in the control group versus 13.3 and 5.0% in the fentanyland morphine groups, respectively. Laryngospasm developed in11.7% of controls compared with 3.3 and 1.7% in the fentanyland morphine groups, respectively. More patients in the controlgroup had excitatory movements (46.7%) than in the fentanyl(16.7%) and morphine (8.3%) groups. These results demonstratethat i.v. opioids reduce airway irritability significantly duringinhalational induction with desflurane in adults. Br J Anaesth 2000: 84; 364–7     

CEREBROVASCULAR CARBON DIOXIDE REACTIVITY DURING EXPOSURE TO EQUIPOTENT ISOFLURANE AND ISOFLURANE IN NITROUS OXIDE ANAESTHESIA

We have studied the effects of hypocapnia on cerebrovascularchanges in two MAC-equivalent anaesthetic regimens, using thetranscranial Doppler technique as an index of cerebral bloodflow (CBF) in 24healthy ASA I patients undergoing spinal surgery.Eight of the patients were subjected to carbon dioxide reactivitychallenges in the awake state. Before surgery, the other 16patients received, in random order, either 1.15% isofluranein oxygen or 0.5% isoflurane with 70% nitrous oxide. Carbondioxide reactivity was calculated for each group as the increasein flow velocity per kPa change in PÉ_CO2 (cm s^–1kPa^–1). It was significantly greater for the isofluranegroup (14.09 (SD 2.44) cm s^–1 kPa^–1) and significantlyless for the isoflurane—nitrous oxide group (7.95 (1.32)cm s-^–1 kPa^–1) compared with the awake group (11.24(0.95) cm s^–1 kPa^–1). We conclude that cerebrovascularresponsiveness to changes in arterial carbon dioxide concentrationis influenced markedly by the anaesthetic procedure. Hyperventilationis more likely to affect CBF during isoflurane anaesthesia thanduring an MAC-equivalent isoflurane—nitrous oxide anaesthesia.     

Anticholinergic premedication influences the incidence of postoperative shivering

We studied 225 healthy adult patients undergoing ENT, dentalor orthopaedic surgery; they were allocated randomly to receiveone of three different premedications, all given i.m. 1 h beforeoperation. Group 1 received morphine 0.15 mg kg^–1 andmetoclopramide 10 mg; group 2 received morphine 0.15 mg kg^–1and glycopyrronium 5 µg kg^–1; group 3 received morphine0.15 mg kg^–1 and hyoscine 5 µg kg^–1. Patientswho were premedicated with an anticholinergic had a significantlygreater incidence and severity of postoperative shivering thanthose in the metoclopramide group. There was no difference incore temperature between patients who shivered and those whodid not, either before or during the shivering episode. Shiveringdid not cause any clinically significant changes in heart rate,arterial pressure, ventilatory frequency or oxygen saturation.As this effect occurred with both glycopyrronium and hyoscine,it suggests that the mechanism by which postoperative shiveringis influenced is peripheral to the central nervous system. (Br.J. Anaesth. 1994; 72: 291-294)      

Inotropic support during cardiac surgery

Editor—We read with interest the article on the incidence,and risk calculation for utilisation, of inotropic support inpatients undergoing cardiac surgery.¹ The findings of the independentpredictors of ventricular dysfunction (presence of chronic obstructivepulmonary disease,     

Influence of dose on suxamethonium-induced muscle damage

We have examined postoperative muscle pain and early increasesin serum concentrations of myoglobin after administration ofsuxamethonium to see if these changes were dependent on thedose of drug. Thirty ASA I and II adult patients undergoingday-case surgery received a standard anaesthetic technique,including one of three doses of suxamethonium: 0.5, 1.5 or 3.0mg kg^–1. The incidence of postoperative myalgia and theseverity of fasciculations were greater after suxamethonium1.5mg kg^–1 than after a dose of 0.5 or 3.0 mg kg^–1.Serum concentrations of myoglobin increased in a dose-dependentmanner. Intubating conditions were significantly better withsuxamethonium 1.5 or 3.0 mg kg^–1 than with 0.5 mg kg^–1.Changes in serum concentrations of calcium and potassium weresmall and similar in the three groups. We conclude that a doseof 3.0 mg kg^–1 of suxamethonium provided a better combinationof intubating conditions and minimal postoperative myalgia thanthe two lower doses. ^*Present address for correspondence: Belfast City Hospital,Lisburn Road, Belfast BT9 7AB, Northern Ireland     

VENOUS SEQUELAE FOLLOWING I.V. ADMINISTRATION OF DICLOFENAC

Diclofenac sodium (Voltarol) was administered i.v. to 149 consecutivepatients who were thought likely to benefit from its anti-inflammatoryaction. Patients were allocated randomly to one of two groups:group A received the undiluted i.m. preparation (25 mg ml^–1)and group B the i.m. preparation diluted in normal saline (5mg ml^–1). Diclofenac 1 mg kg^–1 administered overa 10-min period via a 23-gauge needle into a vein at eitherthe antecubital fossa or the dorsum of the hand. No local orsystemic problems were encountered in either group, at the timeof injection. A high incidence of painless local venous thrombosisoccurred in both hand and arm veins, 72 h after administrationin group A (85% and 58%, respectively). The incidence of thrombosiswas reduced markedly after administration of the diluted drug:38% hand veins; 8% antecubital fossa veins.