The changing practice of thoracic epidural analgesia in the United Kingdom: 1997-2004.

The clinical governance framework and medico-legal climate in the United Kingdom has changed significantly in the past 7 years. We used a postal questionnaire to survey thoracic epidural practice in the United Kingdom in 1997 and repeated this survey in 2004. The response rate to both surveys was 59-60%. There has been considerable change in respect of taking specific consent for thoracic epidural analgesia (24% in 1997, 74% in 2004), awake epidural cannulation (40% in 1997, 84% in 2004), availability of an acute pain service (47% in 1997, 95% in 2004) and HDU-only nursing of patients (63% in 1997, 30% in 2004). Of the 2004 respondents, < 1% used the newer, less toxic local anaesthetics, 49% would consider inserting a thoracic epidural in patients receiving clopidogrel, and 34% would consider inserting a thoracic epidural in patients receiving both aspirin and clopidogrel. A central register of thoracic epidural complications would assist in further developing practice.

Randomized clinical trial to determine the effect of nasogastric drainage on tracheal acid aspiration following oesophagectomy.

BACKGROUND: The aim of this study was to investigate tracheal acid aspiration after oesophagectomy and to determine whether it is influenced by nasogastric (NG) drainage. METHODS: Thirty-four patients undergoing oesophagectomy were randomized to one of three methods of NG drainage: a single-lumen tube with free drainage and 4-hourly aspiration, a sump-type tube on continuous suction drainage, or no NG tube. A tracheal pH probe was used to collect information on acid aspiration for 48 h after surgery. A pH < 5.5 was considered abnormal (normal pH 6.8-7.2). Total time with tracheal pH < 5.5, number of reflux episodes and longest reflux time were compared between groups. RESULTS: There was significant and persistent tracheal acid aspiration in all patients. Patients with a sump-type tube had a significantly shorter total time with tracheal pH < 5.5 than those in the other groups (sump-type tube versus single-lumen tube, P = 0.0069; sump-type tube versus no tube, P = 0.0071). Patients randomized to no NG tube experienced more respiratory complications after surgery than those who had either single-lumen or sump-type tubes (seven of 12 versus four of 22 patients; P = 0.023). Insertion of a NG tube was necessary in the first week after surgery in seven of 12 patients in this group. CONCLUSION: Routine NG drainage after oesophagectomy is necessary. A sump-type NG tube is better at preventing tracheal acid aspiration and may reduce the incidence of respiratory complications.

The effect of gel lubrication on cuff leakage of double lumen tubes during thoracic surgery.

High-volume, low-pressure tracheal cuffs of disposable double lumen tubes may offer limited protection to the dependent lung if fluid leaks through folds in the inflated cuffs. This study was undertaken to determine the incidence of fluid leakage past the tracheal cuff and whether gel lubrication reduces the incidence. Fifty-five patients were randomly assigned to receive a double lumen tube with or without gel lubrication. The dependent lung was intubated. With the patient in the lateral position, methylthionium chloride was administered above the tracheal cuff via a pre-attached catheter. Fibreoptic bronchoscopy was performed to determine if dye had passed the tracheal cuff. Three patients were excluded. Dye leakage was seen in 12/27 and 3/25 patients in the unlubricated and lubricated group, respectively (p = 0.014). Gel lubrication significantly reduces fluid leakage past the tracheal cuff of a double lumen tube and should be considered for all thoracic surgical patients requiring one-lung ventilation.

Double-blind comparison of intrapleural saline and 0.25% bupivacaine for ipsilateral shoulder pain after thoracotomy in patients receiving thoracic epidural analgesia.

BACKGROUND: The aim of this prospective double-blind randomized placebo-controlled study was to investigate the effect of intrapleural bupivacaine on ipsilateral post-thoracotomy shoulder pain in patients receiving thoracic epidural analgesia. METHODS: Of the 68 patients recruited to the study, 41(60%) developed ipsilateral shoulder pain within 2 h of surgery. These patients were randomly assigned to receive either 40 ml of intrapleural bupivacaine 0.25% with epinephrine 1:200 000 or 40 ml of intrapleural saline. The study solution was injected into the tube of a basal drain that had been clamped distal to the site of administration. Shoulder pain at rest and on coughing was assessed using a visual analogue scale (VAS) and an observer verbal rating score (OVRS) immediately before and 30 min, 1 h, 2 h, 3 h and 4 h after intrapleural bupivacaine/saline. The total volume of epidural solution administered was recorded. RESULTS: Thirty-nine patients completed the study and were included in the analysis. There were no significant differences in baseline characteristics between the two groups. There were no significant differences between groups for VAS or OVRS pain scores at rest or with cough at any of the six assessment times. The total volumes of epidural solution administered to the bupivacaine and saline groups were 56 ml and 48 ml, respectively. This difference was not significant. CONCLUSION: Intrapleural administration of 40 ml of bupivacaine 0.25% does not provide effective pain relief for ipsilateral post-thoracotomy shoulder pain.

A prospective, randomised, single-blind pilot study to determine the effect of anaesthetic technique on troponin T release after off-pump coronary artery surgery.

Ischaemic damage to the myocardium inevitably occurs during coronary artery surgery. However, the extent of the damage may be influenced by the anaesthetic technique used. The most sensitive and reliable marker of myocardial damage is currently thought to be troponin T. We conducted a prospective, randomised, single-blind pilot study to determine the baseline values of troponin T release after off-pump coronary artery bypass surgery in 30 patients randomly allocated to receive either propofol, isoflurane or isoflurane and high thoracic epidural analgesia. All other treatment was standardised. Patients undergoing emergency surgery and those with unstable angina were excluded. Blood samples were taken at 0, 3, 6, 12, 24 and 48 h after surgery for troponin T analysis. Mean troponin T levels at 24 h were not significantly different between the groups (p = 0.41). These data allows appropriate power calculations for further, large-scale studies to determine the anaesthetic technique that provides optimal myocardial protection.

Optimal concentration of epidural fentanyl in bupivacaine 0.1% after thoracotomy.

BACKGROUND: The aim of this prospective, double-blind, randomized controlled trial was to investigate the analgesic and adverse effects of three commonly used concentrations of thoracic epidural fentanyl with bupivacaine in patients undergoing thoracotomy for lung resection. METHODS: We studied 99 patients who were randomized to receive fentanyl 2 microg ml(-1) (group 2), fentanyl 5 microg ml(-1) (group 5) and fentanyl 10 microg ml(-1) (group 10) in bupivacaine 0.1% via a thoracic epidural. Postoperatively, pain on coughing was assessed using a visual analogue scale (VAS) and an observer verbal rating score (OVRS) at 2, 8, 16 and 24 h. At the same times, sedation, pruritus and nausea were assessed. RESULTS: Of 29, 28 and 32 patients who completed the study in groups 2, 5 and 10 respectively, there was no significant difference in baseline characteristics between the three groups. The number of patients with episodes of unsatisfactory pain, i.e. VAS scores >30 mm and OVRS >1, at each of the four assessments postoperatively was significantly (P<0.01) higher in group 2 than in groups 5 and 10. In group 10, 16 patients had sedation scores >1 compared with 10 each in groups 2 and 5. In addition, 19 patients in group 10 experienced pruritus compared with 12 each, in groups 2 and 5. These differences were not significant. Nausea was not significantly different between the three groups. CONCLUSION: We conclude that thoracic epidural fentanyl 5 microg ml(-1) with bupivacaine 0.1% provides the optimum balance between pain relief and side effects following thoracotomy.

Infection control measures for adult cardiac surgery in the UK--a survey of current practice.

The aim of the study was to define current UK practice for antimicrobial prophylaxis and preoperative screening for bloodborne viruses and methicillin-resistant Staphylococcus aureus (MRSA) before routine cardiac surgery. An e-mail survey was sent to the Association of Cardiothoracic Anaesthetists (ACTA) Linkmen in all 36 UK adult cardiac surgical units, during May 2001. Questions were asked regarding MRSA, hepatitis B, C and human immunodeficiency virus (HIV) screening. Regarding antimicrobial prophylaxis questions were asked regarding agent(s), dose, frequency and duration of use for coronary artery and value surgery. Responses were received from 29 units (response rate 81%). There was a wide variety of practices for all units surveyed. For MRSA screening, 19 units (65%) screened all patients before surgery, but two (7%) screened none, with the remaining eight units (28%) screening selected high-risk groups. Regarding screening for bloodborne viruses: eight units (28%) tested all patients routinely for hepatitis B, 11 units (39%) selectively tested only high-risk patients and transplant recipients. No units tested for hepatitis C and HIV infection routinely. All units used prophylactic antibiotics routinely, but the type and number of agents, along with dose and duration of therapy all varied widely. For coronary artery bypass graft (CABG) surgery, a single agent was used by 16 units (55%), two agents by 12 units (41%) and three agents by one unit (4%). There is a wide variation in infection control practice in adult cardiac units throughout the UK. Rationalization of preoperative screening and use of prophylactic antibiotics, by adopting nationally agreed practice guidelines, could significantly reduce costs and potentially reduce the incidence of resistant organisms.

Gastric emptying in post-thoracotomy patients receiving a thoracic fentanyl-bupivacaine epidural infusion.

BACKGROUND AND OBJECTIVE: The effect of anaesthesia and surgery on gastric emptying is not constant, and this has not been previously studied in patients undergoing thoracotomy for lung resection with a bupivacaine-fentanyl epidural infusion for analgesia. There are important implications in this group of patients with regards to the recommencement of important oral medication as well as the risks of aspiration of gastric contents. The study examined gastric emptying in these patients until the second postoperative day. METHODS: In a prospective repeated measures study, the effect of fentanyl-bupivacaine epidural analgesia at the mid-thoracic level on gastric emptying was assessed in 11 patients undergoing thoracotomy for lung resection. Gastric emptying was measured using a paracetamol absorption technique. Patients acted as their preoperative controls and were assessed 4 h postoperatively and on the second postoperative day. RESULTS: The mean (SEM) maximum plasma paracetamol concentration was 204.6 (20.4) micromol L(-1) before operation, 61 (9.5) micromol L(-1) 4 h postoperatively and 114.3 (22.6) micromol L(-1) on the second postoperative day. Mean (SEM) paracetamol absorption at 120 min was 15,638 (1441) micromol min L(-1) preoperatively, 5731 (821) micromol min L(-1) 4 h postoperatively and 9325 (1759) micromol min L(-1) on the second postoperative day. Postoperative values were significantly (P < 0.005) less than the preoperative values. CONCLUSIONS: After thoracotomy, gastric emptying was delayed until at least the second postoperative day in patients receiving mid-thoracic fentanyl-bupivacaine epidural analgesia.

Isoflurane and coronary heart disease.

Early studies indicated that isoflurane caused coronary steal and should therefore be avoided in patients with coronary heart disease. Subsequently, more detailed trials have disputed this and have shown that as long as coronary perfusion pressure is maintained, isoflurane does not cause coronary steal or myocardial ischaemia. There is now growing evidence, initially in animal work but more recently in human studies, that isoflurane has myocardial protective properties, limiting infarct size and improving functional recovery from myocardial ischaemia. The mechanism for this protection mimics ischaemic preconditioning and involves the opening of adenosine triphosphate-dependent potassium channels. The few studies comparing the myocardial protection offered by individual anaesthetic agents indicate that isoflurane represents the anaesthetic agent of choice for patients with coronary heart disease.

Ipsilateral shoulder pain after thoracotomy with epidural analgesia: the influence of phrenic nerve infiltration with lidocaine.

UNLABELLED: Patients receiving effective thoracic epidural analgesia for postthoracotomy pain may still complain of severe ipsilateral shoulder pain. The etiology of this pain is unclear. In this randomized, double-blinded, placebo-controlled study, we investigated the effect of phrenic nerve infiltration with lidocaine or saline on postoperative shoulder pain in 48 patients. After completion of a lung resection, patients received either 10 mL of 1% lidocaine or 10 mL of 0.9% saline infiltrated into the periphrenic fat pad at the level of the diaphragm. Shoulder pain was experienced by 33% of patients receiving lidocaine, compared with 85% of patients receiving saline (P < 0.008). Overall pain scores were lower with lidocaine (P < 0.05). PaCO(2) values were not significantly higher with lidocaine in the first 2 h. We conclude that pain transmitted via the phrenic nerve and referred to the shoulder is the most likely explanation for the ipsilateral shoulder pain experienced by patients receiving epidural analgesia for postthoracotomy pain. IMPLICATIONS: Ipsilateral shoulder pain after thoracotomy is common and may be severe, even in the presence of a functioning thoracic epidural. We have shown that infiltration of the phrenic nerve with local anesthetic significantly and safely reduces this shoulder pain, potentially allowing the ideal goal of a pain-free thoracotomy.

A comparison of the effects of desflurane and isoflurane on arterial oxygenation during one-lung ventilation.

In a randomised prospective cross-over study, we compared the effects of desflurane and isoflurane on arterial oxygenation, heart rate and mean arterial pressure during one-lung anaesthesia. Thirty patients scheduled for oesophagogastrectomy were randomly assigned to one of two groups. One group of 15 patients received desflurane to an end-tidal concentration of 6% in oxygen from induction until the end of 30 min of open chest one-lung ventilation in the lateral position. This was followed by isoflurane to an end-tidal concentration of 1.1% in oxygen for the next 30 min of one-lung ventilation. The other group of 15 patients received the two anaesthetic agents in the reverse order. We found no significant difference in arterial oxygenation, heart rate or mean arterial pressure between the two inhalational agents. In the subgroup of 10 patients with pulmonary artery catheters, we found no significant differences in mixed venous saturation, derived shunt or cardiac output. We conclude that during one-lung ventilation, the choice between desflurane and isoflurane does not significantly influence arterial oxygenation.

Induction of anaesthesia in patients with coronary artery disease: a comparison between sevoflurane-remifentanil and fentanyl-etomidate.

In a prospective, randomized study, sevoflurane-remifentanil (Group SR) was compared with fentanyl-etomidate (Group FE) for induction of anaesthesia in patients with ischaemic heart disease. Cardiovascular stability, heart rate, mean arterial pressure, rate pressure product, rescue medications and associated myocardial ischaemia were measured. For Group SR (n = 20), anaesthesia was induced with vital capacity breaths of sevoflurane 5% in oxygen. After loss of consciousness, the inspired sevoflurane was reduced to 3% and remifentanil was administered as a 0.5 microgram.kg-1 bolus over 90 seconds (0.33 microgram.kg-1.min-1) followed by a 0.025 microgram.kg-1.min-1 infusion. After intubation, the inspired sevoflurane was reduced to 2%. For Group FE (n = 20), anaesthesia was induced with fentanyl 10.5 micrograms.kg-1 and etomidate 0.2 mg.kg-1 given 60 seconds later. Isoflurane 1% in oxygen was administered after loss of consciousness. Both groups received rocuronium and the trachea was intubated two minutes later. Sevoflurane gaseous induction was smooth, with cardiovascular stability comparable to fentanyl-etomidate. Significantly more patients in Group SR (P < 0.05) were on beta-blocking medication, and, overall, the HR and RPP was lower pre-intubation in Group SR. Remifentanil administration was associated with severe bradycardia in three patients and asystole in a fourth. All four patients were on beta-blocking medication and three of the four were on diltiazem. The study was terminated due to the high incidence of bradycardic/asystolic complications in Group SR.

Thoracic epidural infusions for post-thoracotomy pain: a comparison of fentanyl-bupivacaine mixtures vs. fentanyl alone.

A randomised double-blind clinical trial was conducted on 106 patients scheduled for pulmonary resection. Patients received an epidural infusion containing 0.1%, 0.2% bupivacaine or saline in combination with fentanyl 10 microgram.ml -1. Adequacy of analgesia was assessed at rest and during movement over 24 h. Analgesic efficacy was assessed using visual analogue scores and an observer/verbal ranking scale. Pain scores were higher in the fentanyl-only group at the 2 h assessment (p < 0.05). Otherwise, there were no between-group differences in pain scores or in the total amounts of epidural solution used. All patients received continuous haemodynamic monitoring. There were no between-group differences in the number of episodes of hypotension or in the number of interventions for hypotension. However, the use of intra-operative vasopressor and the incidence of temporary neurological complications was higher in the 0.2% bupivacaine group (p < 0.05). We conclude that, in the early postoperative period, the addition of bupivacaine 0.1% improves fentanyl epidural analgesia in patients undergoing lung resection and is not associated with the disadvantages seen with the addition of bupivacaine 0.2%.

Myocardial ischaemia after coronary artery bypass grafting: early vs late extubation.

The technique of early extubation after coronary artery bypass grafting is increasing in popularity, but its safety and effect on myocardial ischaemia remain to be established. In a randomized, prospective study, patients undergoing routine elective coronary artery bypass grafting were managed with either early or late tracheal extubation. The incidence and severity of electrocardiographic myocardial ischaemia were compared. Data were analysed from 85 patients (43 early extubation; 42 late extubation). Median time to extubation was 110 min in the early extubation patients and 757 min in the late extubation patients. After correction for randomization bias, there were no significant differences between groups in ischaemic burden, maximal ST-segment deviation, incidence of ischaemia and area under the ST deviation-time curve (integral of ST deviation and time). Similarly, there were no differences between groups in postoperative creatine kinase MB-isoenzyme concentrations and duration of stay in the ICU or hospital. Therefore, this study provides evidence for the safety of early extubation after routine coronary artery bypass grafting.

A survey of the practice of thoracic epidural analgesia in the United Kingdom.

A postal survey of the practice of thoracic epidural analgesia was sent to 275 hospitals in the United Kingdom. Responses were received from 70% of hospitals. Informed consent is rarely adequately obtained, with only 28% of respondents mentioning even the most common complications. Epidural cannulation is most often (60%) performed following induction of general anaesthesia, rather than in the awake patient. A test dose of local anaesthetic without adrenaline is usual. Neither aspirin nor low-dose heparin are considered a contraindication. The majority of respondents used a combination of bupivacaine with fentanyl (51%) or diamorphine (40%), usually administered by continuous infusion. Drugs were frequently prepared and adjusted by anaesthetic staff. The majority of epidurals (63%) are nursed in intensive care units postoperatively. Properly funded pain management teams, at present unusual, would facilitate ward-based epidural management and release intensive care resource. A central register of epidural complications is required to provide valuable evidence for the optimum practice of thoracic epidural analgesia.

Comparison of the effects of sevoflurane and isoflurane on arterial oxygenation during one lung ventilation.

We have compared the effects of sevoflurane and isoflurane on arterial oxygenation, heart rate and mean arterial pressure during one lung anaesthesia in a prospective, crossover study. We studied 28 patients undergoing oesophagogastrectomy, allocated alternatively to one of two groups. Patients in group I/S (n = 14) received 1 MAC (1.1%) of isoflurane in oxygen from induction until the end of 30 min of open chest one lung ventilation (OLV) in the lateral position. This was followed by 1 MAC (2.1%) of sevoflurane in oxygen for the next 30 min of OLV. Patients in group S/I (n = 14) received the two anaesthetic agents in the reverse order. We found no significant difference in arterial oxygenation, heart rate or mean arterial pressure between the two potent inhalation agents. In the subgroup of patients with pulmonary artery catheters (n = 12), we found a significant increase (P < 0.05) in derived shunt during sevoflurane anaesthesia. There was no significant difference in mixed venous saturation and cardiac output. We conclude that during one lung ventilation, the choice between sevoflurane and isoflurane did not significantly influence arterial oxygenation.