- Email: [email protected]
Epidural haematoma
Correspondence
Table 1 Sevoflurane concentrations (%) measured by gas chromatography (GC) and infrared (IR) analysis in different carrier gases IR analyser #
Carrier gas O2
I II III IV
O2
N2O
N2O+CO2
N2
H2O
GC
IR
GC/IR
GC
IR
GC/IR
GC
IR
GC/IR
GC
IR
GC/IR
GC
IR
GC/IR
GC
IR
GC/IR
1.01 1.18 1.01 1.15
1.01 1.10 0.99 1.02
100 108 102 112
1.90 2.01 1.71 1.80
1.88 1.80 1.67 1.64
101 112 102 109
0.91 1.05 0.95 1.05
0.93 0.98 0.91 0.98
98 107 104 107
0.88 0.98 1.03 0.84
0.88 0.89 1.00 0.77
100 110 103 109
1.02 1.03 1.01 0.85
1.01 0.94 0.97 0.78
101 111 104 109
0.83 1.85 1.73 0.81
0.84 1.70 1.66 0.77
98 109 104 106
standard to measure absolute concentrations of inhaled anaesthetics. J. F. A. Hendrickx1* R. Carette2 H. J. M. Lemmens1 A. M. De Wolf3 1 Stanford, CA, USA 2 Aalst, Belgium 3 Chicago, IL, USA *E-mail: [email protected] 1 Hendrickx JFA, Carette R, Lemmens HJM, De Wolf AM. Large volume N2O uptake alone does not explain the second gas effect of N2O on sevoflurane during constant inspired ventilation. Br J Anaesth 2006; 96: 391–5 2 Severinghaus JW, Larson CP, Eger EI. Correction factors for infrared carbon dioxide pressure broadening by nitrogen, nitrous oxide and cyclopropane. Anesthesiology 1961; 22: 429–32 doi:10.1093/bja/ael163
Epidural haematoma Editor—We read with interest the recent case report in which a patient treated with clopidogrel and dalteparin developed an epidural haematoma following a combined spinal-epidural anaesthetic.1 Although the authors describe the commonly quoted incidence of spinal haematoma following epidural and spinal anaesthesia between 1 in 150 000 and 1 in 220 000, the true incidence is unknown. The Victorian Consultative Council on Anaesthetic Mortality and Morbidity (VCCAMM) is a system that monitors, analyses and reports on key areas of potentially preventable anaesthetic mortality and morbidity within the Victorian hospital system in Australia.2 It has recently reported a number of major complications following regional anaesthesia techniques with concerns regarding the delay in diagnosis and treatment of neurological compromise.3 Unfortunately Tam and colleagues1 in their discussion omit practical advice on how spinal haematomas can be diagnosed, given the necessity for an urgent response to begin corrective treatment within a narrow 6–12 h
263
Downloaded from http://bja.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
calibrated using the appropriate calibration gas from the company. Because new mixtures were made for each of the four analysers tested, none of the mixtures contained exactly the same sevoflurane concentration; this is illustrated by the different results for the GC analysis for samples with supposedly the same concentration (Table1). We therefore calculated the ratio of the GC over the IR value, expressed in %. These GC/IR ratios were statistically analysed using the t-test to compare O2 groups and two-way ANOVA to determine the effect of the constitution of the carrier gas. The results are presented in Table 1. The response of the analysers was linear between 1 and 2% (P>0.05), carrier gas composition had no significant effect, but the analysers differed from one another, except for analyser II and IV. How do the results pertain to the interpretation of the results of our previous study? Individual modules differ slightly but unpredictably in their accuracy, but this is not an issue because the same module was used for all patients. Second, the module’s response is linear in the range of the sevoflurane concentrations relevant to our study, 1–2%. Third, carrier gas composition has minimal effect on IR analysis, making it unlikely that the in- and end-expired sevoflurane concentrations in the O2 and O2/N2O groups would be differently affected. Within each of the O2/N2O groups, the inspired and end-expired N2O concentrations differ by less than 10% (absolute value), further reducing the possibility of N2O differently affecting the in- and expired sevoflurane concentrations in the N2O groups. Finally, we reported FA/FI, not FA and FI themselves, a distinction that is important. Indeed, if a particular IR analyser would overestimate the ‘true’ sevoflurane concentration by 5%, the ratio of FA/FI would become FA*1.05/FI*1.05; in other words, IR technology should give us a virtually identical FA/FI ratio. Therefore, in our opinion, the potential small error introduced by the presence of N2O on IR measurement of sevoflurane concentration does not annihilate the results of our study. We conclude that the accuracy of the IR analyser was sufficient to support the conclusion of our study: the second gas effect cannot be adequately explained only by large amounts of N2O uptake. However, we concur with Prof. Severinghaus that GC remains the gold
Correspondence
R. G. Davies* N. A. Harris Cardiff, UK *E-mail: [email protected]
Editor—We read with interest the case report by Tam and colleagues1 describing epidural haematoma following combined spinal-epidural (CSE) anaesthesia for total knee arthroplasty in a patient receiving clopidogrel. This case highlights the importance of vigilance in these patients. Despite adhering to American Society of Regional Anesthesia and Pain Medicine (ASRA) guidelines and recommendations the patient unfortunately developed a rare but potentially devastating complication of central neuraxial blockade. We wonder whether current recommendation from ASRA, of stopping clopidogrel 7 days before neuraxial blockade, needs to be reviewed.4 The risk of CSE in patients treated with newer antiplatelet agents is unclear. The routine laboratory tests for assessing coagulation are not effective for monitoring platelet function inhibition with these agents. Modified thromboelastography could prove useful for monitoring reversal of clopidogrel inhibition.5 Altered coagulation is recognized as an important risk factor in the development of spinal haematoma. Peripheral nerve blockade (PNB) may be a less risky alternative to central neuraxial blockade in unilateral lower limb arthroplasty.6 The increasing use of
clopidogrel may alter the balance of argument in favour of PNB and against CSE in the setting of orthopaedic procedure. S. R. Sawant* M. Bhagwat Kings Lynn, UK *E-mail: [email protected]
Editor—We would like to thank Drs Davies and Harris for their interest and comments regarding the case report. By publishing this case report we hope to maintain and increase awareness of a complication that although rare can have devastating consequences for the patient. It is often easier in retrospect to see the sequence of events and the combination of physical signs suggesting an epidural haematoma. With reference to our case the patient did complain of back pain although she was known to suffer from a degenerative spine. However, we agree that in combination with the abnormal neurology that subsequently developed, such ‘red flag’ signs should cause one to immediately consider an epidural haematoma. Although the physiotherapist noted some abnormal neurology, this information was not conveyed to the duty anaesthetic team. Guidelines in our hospital have since been reviewed to ensure adequate monitoring of patients receiving central neuraxial anaesthesia. Any suspicion of an epidural haematoma should in the first instance involve stopping or reducing the infusion to assess if the signs regress. Further regular assessment is necessary because of the narrow window of opportunity for intervention as mentioned by Davies. The unfortunate delay between the time from when the haematoma was suspected to obtaining an MRI was mainly because of the need to transfer the patient to another hospital. We would like to thank Drs Sawant and Bhagwat for their interest in our case report. Clopidogrel has an irreversible effect on platelet function and at the time of the incident the manufacturer’s recommendations was to stop the agent 7 days before surgery. However, since this case we have changed practice in our department to stopping clopidogrel 10 days before elective surgery. Bleeding time is not an ideal measurement of platelet function in patients on antiplatelet agents and as mentioned modified thromboelastography5 (TEG ) may become a necessary test to assess such patients. A preoperative bedside test would resolve issues regarding platelet function in such patients, especially as the use of combinations of antiplatelet agents is becoming more prevalent. Although guidelines are present for the performance of neuraxial blocks on patients receiving anticoagulants there are few recommendations for peripheral blocks. There have been case reports of severe bleeding complications including fatal outcomes in patients that have undergone lower extremity peripheral nerve blocks and ASRA
264
Downloaded from http://bja.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
‘window of opportunity’. VCCAMM has responded with useful advice to detect such complications.3 Common presenting signs and symptoms of neurological compression include onset of new severe or persistent back pain, loss or change of motor function (which may be erroneously attributed to the local anaesthetic), major change in sensory level or density, any deterioration in observed parameters from a pre-existing steady state, and most importantly there must be recognition of the need to communicate urgently with an anaesthetist or acute pain team. It is disappointing that the patient had complained of back pain in the evening of the day of surgery with abnormal neurology detected the day after surgery and yet there was a 48 h delay after removing the epidural catheter before obtaining a magnetic resonance imaging (MRI) scan to detect what is a neurosurgical emergency. However, the authors are to be congratulated on publishing and highlighting a complication that we believe is under-reported. If a spinal haematoma is suspected, an urgent MRI or computed tomography myelogram and neurological or neurosurgical referral within hours is essential. Clearly, the diagnosis of spinal haematomas is difficult. However, given the ever increasing use of clopidogrel, low molecular weight heparins and other newer anticoagulants, we agree with Tam and colleagues that it is vital that we increase our vigilance and close neurological monitoring of these patients who undergo spinal and/or epidural anaesthesia.
Correspondence
N. L. Tam* C. Pac-Soo P. M. Pretorius High Wycombe, UK *E-mail: [email protected] 1 Tam NL, Pac-Soo C, Pretorius PM. Epidural haematoma after a combined spinal-epidural anaesthetic in a patient treated with clopidogrel and dalteparin. Br J Anaesth 2006; 96: 262–5 2 Victorian Consultative Council on Anaesthetic Mortality and Morbidity. Available from http://www.health.vic.gov.au/vccamm/ index.htm 3 Victorian Consultative Council on Anaesthetic Mortality and Morbidity. Neurological complications of regional anaesthesia— early consultation with the anaesthetist 2005. Available from http://www.health.vic.gov.au/vccamm/articles/neuro.pdf 4 Horlocker TT, Benzon H, Brown DL, et al. Regional anaesthesia in the anticoagulated patient: defining the risks (the Second ASRA Consensus Conference on Neuraxial Anesthesia and Anticoagulation). Reg Anesth Pain Med 2003; 28: 172–97 5 Craft RM, Chavez JJ, Bresee SJ, et al. A novel modification of the thromboelastograph assay, isolating platelet function, correlates with optical platelet aggregation. J Lab Clin Med 2004; 143: 301–9 6 Mentegazzi F, Danelli G, Ghisi D, et al. Locoregional anesthesia and coagulation. Minerva Anesthesiol 2005; 71: 497–9 doi:10.1093/bja/ael164
Acute pain management Editor—Macintyre and colleagues1 highlighted the increasing role of the acute pain service across the spectrum of inpatient pain problems. We have conducted an audit at the James Cook University Hospital to find out the contribution of the inpatient pain service to the management of non-postoperative pain. This audit was conducted over a 3 month period from November 2005 to January 2006. During this period, 563 patients were seen by the acute pain service of which 114 (20%) were not postoperative patients (Table 1). About half of the patients (59) required a single visit, 26 required 2 visits, 14 needed 3 visits, 9 patients were visited
Table 1 The distribution, by speciality, of the non-postoperative patients seen by the inpatient pain service during the audit period Specialty
No. of cases
Orthopaedics and trauma Neurology and neurosurgery Vascular Medicine Surgery Renal Cardiology and cardiovascular surgery Dermatology Others
19 18 15 15 15 5 5 5 17
4 times, and 5 patients had to be seen 5 times or more. On average each visit took 12 min though 7 visits lasted more than 30 min. This meant that the inpatient pain service made 216 visits over the 3 month audit, which equates to 3–4 h work per week for the non-postoperative patients. If this time is not taken into account when allocating resources to the inpatient pain service there is a danger that the core duties of the service that is maintaining high standards of acute pain management and the teaching of medical and nursing staff may be compromised. Another observation made during this audit was that more than half these patients needed only a single visit from the inpatient pain service. This was principally to support and advise the ward staff on an appropriate management plan. Based on this audit it is possible to identify the common conditions requiring input from the inpatient pain service. The pain team can then disseminate the evidence-based guidelines among the referring units and the ward staff to give them more confidence in managing the common pain problems. The inpatient pain service is closely aligned to the chronic pain (outpatient) service. Several patients seen by the inpatients pain service are offered follow-up in the chronic pain clinic following discharge. We need to evaluate further whether the input from the inpatient pain service facilitates earlier discharge from hospital and improves outcomes. A. Date J. Hughes K. Milligan Middlesbrough, UK E-mail: [email protected] 1 Macintyre PE, Walker S, Power I, Schug SA. Acute pain management: scientific evidence revisited. Br J Anaesth 2006; 96: 1–4 doi:10.1093/bja/ael165
Single-use LMAs—a cautionary tale Editor—We read with interest the editorial by Cook1 regarding the recent introduction of single-use, supraglottic airway devices. In response, we would like to describe our local experience of their introduction into clinical
265
Downloaded from http://bja.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
guidelines4 have suggested that recommendations for performing these blocks should be similar to those for neuraxial blocks. Performing a central neuraxial block on patients receiving antithrombotic medication is usually a risk benefit analysis and commonly the population receiving such agents are often the ones that benefit most from a neuraxial or regional technique. The incidence of epidural haematomas is rare and is based on retrospective analysis and case reports but the neurological outcome can be devastating for the patients. By reporting such cases we hope to increase awareness of this complication and vigilance in all patients receiving central neuraxial anaesthesia.
Table 1 Sevoflurane concentrations (%) measured by gas chromatography (GC) and infrared (IR) analysis in different carrier gases IR analyser #
Carrier gas O2
I II III IV
O2
N2O
N2O+CO2
N2
H2O
GC
IR
GC/IR
GC
IR
GC/IR
GC
IR
GC/IR
GC
IR
GC/IR
GC
IR
GC/IR
GC
IR
GC/IR
1.01 1.18 1.01 1.15
1.01 1.10 0.99 1.02
100 108 102 112
1.90 2.01 1.71 1.80
1.88 1.80 1.67 1.64
101 112 102 109
0.91 1.05 0.95 1.05
0.93 0.98 0.91 0.98
98 107 104 107
0.88 0.98 1.03 0.84
0.88 0.89 1.00 0.77
100 110 103 109
1.02 1.03 1.01 0.85
1.01 0.94 0.97 0.78
101 111 104 109
0.83 1.85 1.73 0.81
0.84 1.70 1.66 0.77
98 109 104 106
standard to measure absolute concentrations of inhaled anaesthetics. J. F. A. Hendrickx1* R. Carette2 H. J. M. Lemmens1 A. M. De Wolf3 1 Stanford, CA, USA 2 Aalst, Belgium 3 Chicago, IL, USA *E-mail: [email protected] 1 Hendrickx JFA, Carette R, Lemmens HJM, De Wolf AM. Large volume N2O uptake alone does not explain the second gas effect of N2O on sevoflurane during constant inspired ventilation. Br J Anaesth 2006; 96: 391–5 2 Severinghaus JW, Larson CP, Eger EI. Correction factors for infrared carbon dioxide pressure broadening by nitrogen, nitrous oxide and cyclopropane. Anesthesiology 1961; 22: 429–32 doi:10.1093/bja/ael163
Epidural haematoma Editor—We read with interest the recent case report in which a patient treated with clopidogrel and dalteparin developed an epidural haematoma following a combined spinal-epidural anaesthetic.1 Although the authors describe the commonly quoted incidence of spinal haematoma following epidural and spinal anaesthesia between 1 in 150 000 and 1 in 220 000, the true incidence is unknown. The Victorian Consultative Council on Anaesthetic Mortality and Morbidity (VCCAMM) is a system that monitors, analyses and reports on key areas of potentially preventable anaesthetic mortality and morbidity within the Victorian hospital system in Australia.2 It has recently reported a number of major complications following regional anaesthesia techniques with concerns regarding the delay in diagnosis and treatment of neurological compromise.3 Unfortunately Tam and colleagues1 in their discussion omit practical advice on how spinal haematomas can be diagnosed, given the necessity for an urgent response to begin corrective treatment within a narrow 6–12 h
263
Downloaded from http://bja.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
calibrated using the appropriate calibration gas from the company. Because new mixtures were made for each of the four analysers tested, none of the mixtures contained exactly the same sevoflurane concentration; this is illustrated by the different results for the GC analysis for samples with supposedly the same concentration (Table1). We therefore calculated the ratio of the GC over the IR value, expressed in %. These GC/IR ratios were statistically analysed using the t-test to compare O2 groups and two-way ANOVA to determine the effect of the constitution of the carrier gas. The results are presented in Table 1. The response of the analysers was linear between 1 and 2% (P>0.05), carrier gas composition had no significant effect, but the analysers differed from one another, except for analyser II and IV. How do the results pertain to the interpretation of the results of our previous study? Individual modules differ slightly but unpredictably in their accuracy, but this is not an issue because the same module was used for all patients. Second, the module’s response is linear in the range of the sevoflurane concentrations relevant to our study, 1–2%. Third, carrier gas composition has minimal effect on IR analysis, making it unlikely that the in- and end-expired sevoflurane concentrations in the O2 and O2/N2O groups would be differently affected. Within each of the O2/N2O groups, the inspired and end-expired N2O concentrations differ by less than 10% (absolute value), further reducing the possibility of N2O differently affecting the in- and expired sevoflurane concentrations in the N2O groups. Finally, we reported FA/FI, not FA and FI themselves, a distinction that is important. Indeed, if a particular IR analyser would overestimate the ‘true’ sevoflurane concentration by 5%, the ratio of FA/FI would become FA*1.05/FI*1.05; in other words, IR technology should give us a virtually identical FA/FI ratio. Therefore, in our opinion, the potential small error introduced by the presence of N2O on IR measurement of sevoflurane concentration does not annihilate the results of our study. We conclude that the accuracy of the IR analyser was sufficient to support the conclusion of our study: the second gas effect cannot be adequately explained only by large amounts of N2O uptake. However, we concur with Prof. Severinghaus that GC remains the gold
Correspondence
R. G. Davies* N. A. Harris Cardiff, UK *E-mail: [email protected]
Editor—We read with interest the case report by Tam and colleagues1 describing epidural haematoma following combined spinal-epidural (CSE) anaesthesia for total knee arthroplasty in a patient receiving clopidogrel. This case highlights the importance of vigilance in these patients. Despite adhering to American Society of Regional Anesthesia and Pain Medicine (ASRA) guidelines and recommendations the patient unfortunately developed a rare but potentially devastating complication of central neuraxial blockade. We wonder whether current recommendation from ASRA, of stopping clopidogrel 7 days before neuraxial blockade, needs to be reviewed.4 The risk of CSE in patients treated with newer antiplatelet agents is unclear. The routine laboratory tests for assessing coagulation are not effective for monitoring platelet function inhibition with these agents. Modified thromboelastography could prove useful for monitoring reversal of clopidogrel inhibition.5 Altered coagulation is recognized as an important risk factor in the development of spinal haematoma. Peripheral nerve blockade (PNB) may be a less risky alternative to central neuraxial blockade in unilateral lower limb arthroplasty.6 The increasing use of
clopidogrel may alter the balance of argument in favour of PNB and against CSE in the setting of orthopaedic procedure. S. R. Sawant* M. Bhagwat Kings Lynn, UK *E-mail: [email protected]
Editor—We would like to thank Drs Davies and Harris for their interest and comments regarding the case report. By publishing this case report we hope to maintain and increase awareness of a complication that although rare can have devastating consequences for the patient. It is often easier in retrospect to see the sequence of events and the combination of physical signs suggesting an epidural haematoma. With reference to our case the patient did complain of back pain although she was known to suffer from a degenerative spine. However, we agree that in combination with the abnormal neurology that subsequently developed, such ‘red flag’ signs should cause one to immediately consider an epidural haematoma. Although the physiotherapist noted some abnormal neurology, this information was not conveyed to the duty anaesthetic team. Guidelines in our hospital have since been reviewed to ensure adequate monitoring of patients receiving central neuraxial anaesthesia. Any suspicion of an epidural haematoma should in the first instance involve stopping or reducing the infusion to assess if the signs regress. Further regular assessment is necessary because of the narrow window of opportunity for intervention as mentioned by Davies. The unfortunate delay between the time from when the haematoma was suspected to obtaining an MRI was mainly because of the need to transfer the patient to another hospital. We would like to thank Drs Sawant and Bhagwat for their interest in our case report. Clopidogrel has an irreversible effect on platelet function and at the time of the incident the manufacturer’s recommendations was to stop the agent 7 days before surgery. However, since this case we have changed practice in our department to stopping clopidogrel 10 days before elective surgery. Bleeding time is not an ideal measurement of platelet function in patients on antiplatelet agents and as mentioned modified thromboelastography5 (TEG ) may become a necessary test to assess such patients. A preoperative bedside test would resolve issues regarding platelet function in such patients, especially as the use of combinations of antiplatelet agents is becoming more prevalent. Although guidelines are present for the performance of neuraxial blocks on patients receiving anticoagulants there are few recommendations for peripheral blocks. There have been case reports of severe bleeding complications including fatal outcomes in patients that have undergone lower extremity peripheral nerve blocks and ASRA
264
Downloaded from http://bja.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
‘window of opportunity’. VCCAMM has responded with useful advice to detect such complications.3 Common presenting signs and symptoms of neurological compression include onset of new severe or persistent back pain, loss or change of motor function (which may be erroneously attributed to the local anaesthetic), major change in sensory level or density, any deterioration in observed parameters from a pre-existing steady state, and most importantly there must be recognition of the need to communicate urgently with an anaesthetist or acute pain team. It is disappointing that the patient had complained of back pain in the evening of the day of surgery with abnormal neurology detected the day after surgery and yet there was a 48 h delay after removing the epidural catheter before obtaining a magnetic resonance imaging (MRI) scan to detect what is a neurosurgical emergency. However, the authors are to be congratulated on publishing and highlighting a complication that we believe is under-reported. If a spinal haematoma is suspected, an urgent MRI or computed tomography myelogram and neurological or neurosurgical referral within hours is essential. Clearly, the diagnosis of spinal haematomas is difficult. However, given the ever increasing use of clopidogrel, low molecular weight heparins and other newer anticoagulants, we agree with Tam and colleagues that it is vital that we increase our vigilance and close neurological monitoring of these patients who undergo spinal and/or epidural anaesthesia.
Correspondence
N. L. Tam* C. Pac-Soo P. M. Pretorius High Wycombe, UK *E-mail: [email protected] 1 Tam NL, Pac-Soo C, Pretorius PM. Epidural haematoma after a combined spinal-epidural anaesthetic in a patient treated with clopidogrel and dalteparin. Br J Anaesth 2006; 96: 262–5 2 Victorian Consultative Council on Anaesthetic Mortality and Morbidity. Available from http://www.health.vic.gov.au/vccamm/ index.htm 3 Victorian Consultative Council on Anaesthetic Mortality and Morbidity. Neurological complications of regional anaesthesia— early consultation with the anaesthetist 2005. Available from http://www.health.vic.gov.au/vccamm/articles/neuro.pdf 4 Horlocker TT, Benzon H, Brown DL, et al. Regional anaesthesia in the anticoagulated patient: defining the risks (the Second ASRA Consensus Conference on Neuraxial Anesthesia and Anticoagulation). Reg Anesth Pain Med 2003; 28: 172–97 5 Craft RM, Chavez JJ, Bresee SJ, et al. A novel modification of the thromboelastograph assay, isolating platelet function, correlates with optical platelet aggregation. J Lab Clin Med 2004; 143: 301–9 6 Mentegazzi F, Danelli G, Ghisi D, et al. Locoregional anesthesia and coagulation. Minerva Anesthesiol 2005; 71: 497–9 doi:10.1093/bja/ael164
Acute pain management Editor—Macintyre and colleagues1 highlighted the increasing role of the acute pain service across the spectrum of inpatient pain problems. We have conducted an audit at the James Cook University Hospital to find out the contribution of the inpatient pain service to the management of non-postoperative pain. This audit was conducted over a 3 month period from November 2005 to January 2006. During this period, 563 patients were seen by the acute pain service of which 114 (20%) were not postoperative patients (Table 1). About half of the patients (59) required a single visit, 26 required 2 visits, 14 needed 3 visits, 9 patients were visited
Table 1 The distribution, by speciality, of the non-postoperative patients seen by the inpatient pain service during the audit period Specialty
No. of cases
Orthopaedics and trauma Neurology and neurosurgery Vascular Medicine Surgery Renal Cardiology and cardiovascular surgery Dermatology Others
19 18 15 15 15 5 5 5 17
4 times, and 5 patients had to be seen 5 times or more. On average each visit took 12 min though 7 visits lasted more than 30 min. This meant that the inpatient pain service made 216 visits over the 3 month audit, which equates to 3–4 h work per week for the non-postoperative patients. If this time is not taken into account when allocating resources to the inpatient pain service there is a danger that the core duties of the service that is maintaining high standards of acute pain management and the teaching of medical and nursing staff may be compromised. Another observation made during this audit was that more than half these patients needed only a single visit from the inpatient pain service. This was principally to support and advise the ward staff on an appropriate management plan. Based on this audit it is possible to identify the common conditions requiring input from the inpatient pain service. The pain team can then disseminate the evidence-based guidelines among the referring units and the ward staff to give them more confidence in managing the common pain problems. The inpatient pain service is closely aligned to the chronic pain (outpatient) service. Several patients seen by the inpatients pain service are offered follow-up in the chronic pain clinic following discharge. We need to evaluate further whether the input from the inpatient pain service facilitates earlier discharge from hospital and improves outcomes. A. Date J. Hughes K. Milligan Middlesbrough, UK E-mail: [email protected] 1 Macintyre PE, Walker S, Power I, Schug SA. Acute pain management: scientific evidence revisited. Br J Anaesth 2006; 96: 1–4 doi:10.1093/bja/ael165
Single-use LMAs—a cautionary tale Editor—We read with interest the editorial by Cook1 regarding the recent introduction of single-use, supraglottic airway devices. In response, we would like to describe our local experience of their introduction into clinical
265
Downloaded from http://bja.oxfordjournals.org/ at University of Saskatchewan Library on March 19, 2015
guidelines4 have suggested that recommendations for performing these blocks should be similar to those for neuraxial blocks. Performing a central neuraxial block on patients receiving antithrombotic medication is usually a risk benefit analysis and commonly the population receiving such agents are often the ones that benefit most from a neuraxial or regional technique. The incidence of epidural haematomas is rare and is based on retrospective analysis and case reports but the neurological outcome can be devastating for the patients. By reporting such cases we hope to increase awareness of this complication and vigilance in all patients receiving central neuraxial anaesthesia.