BJA
Correspondence
Declaration of interest None declared. C. Kakazu* M. Lippmann Torrance, CA, USA * E-mail: [email protected] 1 Chew STH, Mar WMT, Ti LK. Association of ethnicity and acute kidney injury after cardiac surgery in a South East Asian population. Br J Anaesth 2013; 110: 397–401 2 Katz RL, Norman J, Seed RF, Conrad L. A comparison of the effects of suxamethoium and tubocurarine in patients in London and New York. Br J Anaesth 1969; 41: 1041–7
doi:10.1093/bja/aet456
did not reach statistical significance (OR 1.399, CI 0.95– 2.0, P¼0.08). We shall be repeating the analyses with a bigger sample of patients. Our study population is unique as the city state is relatively homogenous with a high standard of healthcare and access to healthcare from patients is unimpeded. The two heart centres are public institutions doing more than 80% of all heart surgeries in the country and the distribution of patients between the centres is fairly even, often with porosity between the two. The referral base to these hospitals comes from the various public primary care clinics with little surgeon bias.
Declaration of interest None declared. S. T. Chew* L. K. Ti Singapore, Singapore * E-mail: [email protected] 1 Chew STH, Mar WMT, Ti LK. Association of ethnicity and acute kidney injury after cardiac surgery in a South East Asian population. Br J Anaesth 2013; 110: 397–401 2 Chew STH, Newman MF, White WD, et al. Preliminary report on the association of apolipoprotein E polymorphisms, with postoperative peak serum creatinine concentrations in cardiac surgical patients. Anesthsiology 2000; 93: 325– 31 3 Loef BG, Epema AH, Stegeman CA, et al. Immediate postoperative renal function deterioration in cardiac surgical patients predicts in-hospital mortality and long-term survival. J Am Soc Nephrol 2005; 16: 195–200 4 Ryckwaert F, Boccara G, Colson PH, et al. Incidence, risk factors, and prognosis of a moderate increase in plasma creatinine early after cardiac surgery. Crit Care Med 2002; 30: 1495–8
doi:10.1093/bja/aet453
Ethnicity and acute kidney injury: the correct definition of acute kidney injury? Reply from the authors
Pharmacological perioperative brain neuroprotection: nimodipine?
Editor—We are grateful for this opportunity to reply to Dr Atwal and his colleagues’ comments on our article.1 We used the relatively low fractional change in serum creatinine as it has been previously described in one of our papers.2 Loef and colleagues3 in using the same criteria have shown that the immediate and small decline in renal function is associated not only with early mortality but also mortality in the longer term. A fractional change in serum creatinine of at least 25% represents a decrease in GFR of at least 20% which may be significant in the long term.4 This will identify patients who require specific preventive measures during the follow-up period. We have also analysed the data based on the AKIN criteria and there is a racial difference in that the Malays have a higher risk compared with the Chinese [odds ratio (OR) 1.457, confidence interval (CI) 1.04 –2.0, P¼0.02], but the Indians
Editor—I read with great interest the article ‘Pharmacological perioperative brain neuroprotection: a qualitative review of randomized clinical trials’ by Bilotta and colleagues.1 The authors reviewed 25 randomized clinical trials addressing perioperative pharmacological neuroprotection. They concluded that only atorvastatin and magnesium sulphate were associated with a lower incidence of new postoperative neurological deficits. I would like to draw your attention to a missing prospectively performed, randomized clinical trial with 30 patients published in Neurosurgery revealing the neuroprotective efficacy of perioperative nimodipine medication for the preservation of facial and cochlear nerve functions in vestibular schwannoma surgery.2 The results were significant for a better outcome for both hearing (P¼0.041) and facial nerve (P¼0.045) preservation in the group of patients who received a
178
Downloaded from http://bja.oxfordjournals.org/ at Belgorod State University on December 6, 2013
AKI. Instead of incorporating other South Asian populations, just investigate the Chinese populations of Northern China vs Central vs Southern China and compare the results with Chinese people living in Taiwan or other countries. All these people are relatively homogenous and their socioeconomic factors may be very similar or different. This study would tell us how this single ethnic population reacts to cardiac surgery and postoperative organ dysfunction. The Chinese life style is known to be much higher and better than other South Asian countries. Patient care would be improved substantially. A similar investigation occurred years ago, around 1966– 7 which dealt with two ethnic Caucasian populations in two different countries investigating a neuromuscular blocking agent to see the difference in response.2 This study pointed out that even in similar ethnic groups, there are different reactions. Comparing Chinese groups for AKI would be very interesting and noteworthy to all physicians, anaesthesiologists, and surgeons alike.
BJA
Correspondence
prophylactic nimodipine treatment from the day before surgery until the seventh postoperative day. Based on this pilot study, a randomized, multi-centric clinical phase III is actually being performed in order to confirm the neuroprotective efficacy of nimodipine in vestibular schwannoma surgery. In general, nimodipine reduces the risk for poor outcome and delayed ischaemic neurological deficits and is recommended for the management of aneurysmal subarachnoid haemorrhage.3 Additionally, several animal experiments4 – 7 and clinical series2 8 – 12 reveal its neuroprotective efficacy after skull base, laryngeal, and maxillofacial surgery. Its positive effects have been attributed to neuroprotection.13 However, the underlying cellular mechanisms remain in part unclear.
None declared. C. Scheller* Halle-Wittenberg, Germany * E-mail: [email protected] 1 Bilotta F, Gelb AW, Stazi E, Titi L, Paoloni FP, Rosa G. Pharmacological perioperative brain neuroprotection: a qualitative review of randomized clinical trials. Br J Anaesth 2013; 110 (Suppl. 1): i113– 20 2 Scheller C, Richter HP, Engelhardt M, Koenig R, Antoniadis G. The influence of prophylactic vasoactive treatment on cochlear and facial nerve functions after vestibular schwannoma surgery: a prospective and open-label randomized pilot study. Neurosurgery 2007; 61: 92– 7 3 Dorhout Mees SM, Rinkel GJ, Feigin VL, et al. Calcium antagonists for aneurysmal subarachnoid haemorrhage. Cochrane Database Syst Rev 2007; CD000277 4 Nishimoto K, Kumai Y, Sanuki T, Minoda R, Yumoto E. The impact of nimodipine administration combined with nerve-muscle pedicle implantation on long-term denervated rat thyroarytenoid muscle. Laryngoscope 2013; 123: 952– 9, doi:10.1002/lary.23698 5 Kansu L, Ozkarakas H, Efendi H, Okar I. Protective effects of pentoxifylline and nimodipine on acoustic trauma in Guinea pig cochlea. Otol Neurotol 2011; 32: 919– 25, doi: 10.1097/ MAO.0b013e3182267e06 6 Lindsay RW, Heaton JT, Edwards C, Smitson C, Hadlock TA. Nimodipine and acceleration of functional recovery of the facial nerve after crush injury. Arch Facial Plast Surg 2010; 12: 49 –52, doi:10.1001/ archfacial.2009.95 7 Hydman J, Remahl S, Bjaerck G, Svensson M, Mattsson P. Nimodipine improves reinnervation and neuromuscular function after injury to the recurrent laryngeal nerve in the rat. Ann Otol Rhinol Laryngol 2007; 116: 623– 30 8 Strauss C, Bischoff B, Neu M, Berg M, Fahlbusch R, Romstoeck J. Vasoactive treatment for hearing preservation in acoustic neuroma surgery. J Neurosurg 2001; 95: 771– 7 9 Scheller C, Strauss C, Fahlbusch R, Romstoeck J. Delayed facial nerve paresis following acoustic neuroma resection and postoperative vasoactive treatment. Zentralbl Neurochir 2004; 65: 103–7 10 Strauss C, Romstoeck J, Fahlbusch R, Rampp S, Scheller C. Preservation of facial nerve function after postoperative vasoactive
doi:10.1093/bja/aet459
Reply from the authors Editor—We are grateful to Dr Scheller for his interest in our review.1 Dr Scheller has interestingly drawn our attention to one of his articles, where the effects of continuous infusion of nimodipine (15–30 mg kg21 h21), and hydroxyethylstarch 10% (aimed to maintain a hematocrit between 30% and 35%) started the day before surgery and continued until the seventh postoperative day, on facial nerve paresis and hearing loss after schwannoma surgery were tested.2 Dr Scheller suggests that his study should been included and described in our review. However, it was not for several reasons. (i) As reported in our ‘primary endpoints’, the selected studies should describe: new postoperative neurological deficit as stroke with the appearance of symptoms and/ or focal signs in the physical examination confirmed by computerized tomography imaging, or as a change in postoperative score from preoperative assessment with neurological scales such as the National Institutes of Health Stroke Scale (NIHSS) and the Western Perioperative Neurologic Scale (WPNS).1 Dr Scheller’s study was addressed to evaluate ‘cochlear and facial nerve function’ rather than symptoms or signs of brain damage. (ii) In our review, we describe ‘pharmacological perioperative brain neuroprotection’ and studies related to perioperative protection of cranial and spinal nerve function (that according to traditional anatomical categorization belong to the peripheral nervous system) were not selected.3 Of special interest, as reported in our review, nimodipine was tested in two randomized controlled trials—accomplished in cardiac surgery—with the aim of ‘Pharmacological perioperative brain neuroprotection’.4 5 One of these studies was prematurely aborted because of the unexpected disparity in death rates due to excess postoperative bleeding.5 This additional risk should be carefully considered in future studies with nimodipine.
179
Downloaded from http://bja.oxfordjournals.org/ at Belgorod State University on December 6, 2013
Declaration of interest
treatment in vestibular schwannoma surgery. Neurosurgery 2006; 59: 577– 84 11 Bischoff B, Romstoeck J, Fahlbusch R, Buchfelder M, Strauss C. Intraoperative brainstem auditory evoked potential pattern and perioperative vasoactive treatment for hearing preservation in vestibular schwannoma surgery. J Neurol Neurosurg Psychiatry 2008; 79: 170– 5 12 Scheller K, Scheller C. Nimodipine promotes regeneration of peripheral facial nerve function after traumatic injury following maxillofacial surgery: an off label pilot-study. J Craniomaxillofac Surg 2012; 40: 427–34, doi:10.1016/j.jcms.2011.07.016 13 Rabinstein AA, Lanzino G, Wijdicks EF. Multidisciplinary management and emerging therapeutic strategies in aneurysmal subarachnoid haemorrhage. Lancet Neurol 2010; 9: 504– 19, doi: 10.1016/S1474-4422(10)70087-9
Correspondence
Declaration of interest None declared. C. Kakazu* M. Lippmann Torrance, CA, USA * E-mail: [email protected] 1 Chew STH, Mar WMT, Ti LK. Association of ethnicity and acute kidney injury after cardiac surgery in a South East Asian population. Br J Anaesth 2013; 110: 397–401 2 Katz RL, Norman J, Seed RF, Conrad L. A comparison of the effects of suxamethoium and tubocurarine in patients in London and New York. Br J Anaesth 1969; 41: 1041–7
doi:10.1093/bja/aet456
did not reach statistical significance (OR 1.399, CI 0.95– 2.0, P¼0.08). We shall be repeating the analyses with a bigger sample of patients. Our study population is unique as the city state is relatively homogenous with a high standard of healthcare and access to healthcare from patients is unimpeded. The two heart centres are public institutions doing more than 80% of all heart surgeries in the country and the distribution of patients between the centres is fairly even, often with porosity between the two. The referral base to these hospitals comes from the various public primary care clinics with little surgeon bias.
Declaration of interest None declared. S. T. Chew* L. K. Ti Singapore, Singapore * E-mail: [email protected] 1 Chew STH, Mar WMT, Ti LK. Association of ethnicity and acute kidney injury after cardiac surgery in a South East Asian population. Br J Anaesth 2013; 110: 397–401 2 Chew STH, Newman MF, White WD, et al. Preliminary report on the association of apolipoprotein E polymorphisms, with postoperative peak serum creatinine concentrations in cardiac surgical patients. Anesthsiology 2000; 93: 325– 31 3 Loef BG, Epema AH, Stegeman CA, et al. Immediate postoperative renal function deterioration in cardiac surgical patients predicts in-hospital mortality and long-term survival. J Am Soc Nephrol 2005; 16: 195–200 4 Ryckwaert F, Boccara G, Colson PH, et al. Incidence, risk factors, and prognosis of a moderate increase in plasma creatinine early after cardiac surgery. Crit Care Med 2002; 30: 1495–8
doi:10.1093/bja/aet453
Ethnicity and acute kidney injury: the correct definition of acute kidney injury? Reply from the authors
Pharmacological perioperative brain neuroprotection: nimodipine?
Editor—We are grateful for this opportunity to reply to Dr Atwal and his colleagues’ comments on our article.1 We used the relatively low fractional change in serum creatinine as it has been previously described in one of our papers.2 Loef and colleagues3 in using the same criteria have shown that the immediate and small decline in renal function is associated not only with early mortality but also mortality in the longer term. A fractional change in serum creatinine of at least 25% represents a decrease in GFR of at least 20% which may be significant in the long term.4 This will identify patients who require specific preventive measures during the follow-up period. We have also analysed the data based on the AKIN criteria and there is a racial difference in that the Malays have a higher risk compared with the Chinese [odds ratio (OR) 1.457, confidence interval (CI) 1.04 –2.0, P¼0.02], but the Indians
Editor—I read with great interest the article ‘Pharmacological perioperative brain neuroprotection: a qualitative review of randomized clinical trials’ by Bilotta and colleagues.1 The authors reviewed 25 randomized clinical trials addressing perioperative pharmacological neuroprotection. They concluded that only atorvastatin and magnesium sulphate were associated with a lower incidence of new postoperative neurological deficits. I would like to draw your attention to a missing prospectively performed, randomized clinical trial with 30 patients published in Neurosurgery revealing the neuroprotective efficacy of perioperative nimodipine medication for the preservation of facial and cochlear nerve functions in vestibular schwannoma surgery.2 The results were significant for a better outcome for both hearing (P¼0.041) and facial nerve (P¼0.045) preservation in the group of patients who received a
178
Downloaded from http://bja.oxfordjournals.org/ at Belgorod State University on December 6, 2013
AKI. Instead of incorporating other South Asian populations, just investigate the Chinese populations of Northern China vs Central vs Southern China and compare the results with Chinese people living in Taiwan or other countries. All these people are relatively homogenous and their socioeconomic factors may be very similar or different. This study would tell us how this single ethnic population reacts to cardiac surgery and postoperative organ dysfunction. The Chinese life style is known to be much higher and better than other South Asian countries. Patient care would be improved substantially. A similar investigation occurred years ago, around 1966– 7 which dealt with two ethnic Caucasian populations in two different countries investigating a neuromuscular blocking agent to see the difference in response.2 This study pointed out that even in similar ethnic groups, there are different reactions. Comparing Chinese groups for AKI would be very interesting and noteworthy to all physicians, anaesthesiologists, and surgeons alike.
BJA
Correspondence
prophylactic nimodipine treatment from the day before surgery until the seventh postoperative day. Based on this pilot study, a randomized, multi-centric clinical phase III is actually being performed in order to confirm the neuroprotective efficacy of nimodipine in vestibular schwannoma surgery. In general, nimodipine reduces the risk for poor outcome and delayed ischaemic neurological deficits and is recommended for the management of aneurysmal subarachnoid haemorrhage.3 Additionally, several animal experiments4 – 7 and clinical series2 8 – 12 reveal its neuroprotective efficacy after skull base, laryngeal, and maxillofacial surgery. Its positive effects have been attributed to neuroprotection.13 However, the underlying cellular mechanisms remain in part unclear.
None declared. C. Scheller* Halle-Wittenberg, Germany * E-mail: [email protected] 1 Bilotta F, Gelb AW, Stazi E, Titi L, Paoloni FP, Rosa G. Pharmacological perioperative brain neuroprotection: a qualitative review of randomized clinical trials. Br J Anaesth 2013; 110 (Suppl. 1): i113– 20 2 Scheller C, Richter HP, Engelhardt M, Koenig R, Antoniadis G. The influence of prophylactic vasoactive treatment on cochlear and facial nerve functions after vestibular schwannoma surgery: a prospective and open-label randomized pilot study. Neurosurgery 2007; 61: 92– 7 3 Dorhout Mees SM, Rinkel GJ, Feigin VL, et al. Calcium antagonists for aneurysmal subarachnoid haemorrhage. Cochrane Database Syst Rev 2007; CD000277 4 Nishimoto K, Kumai Y, Sanuki T, Minoda R, Yumoto E. The impact of nimodipine administration combined with nerve-muscle pedicle implantation on long-term denervated rat thyroarytenoid muscle. Laryngoscope 2013; 123: 952– 9, doi:10.1002/lary.23698 5 Kansu L, Ozkarakas H, Efendi H, Okar I. Protective effects of pentoxifylline and nimodipine on acoustic trauma in Guinea pig cochlea. Otol Neurotol 2011; 32: 919– 25, doi: 10.1097/ MAO.0b013e3182267e06 6 Lindsay RW, Heaton JT, Edwards C, Smitson C, Hadlock TA. Nimodipine and acceleration of functional recovery of the facial nerve after crush injury. Arch Facial Plast Surg 2010; 12: 49 –52, doi:10.1001/ archfacial.2009.95 7 Hydman J, Remahl S, Bjaerck G, Svensson M, Mattsson P. Nimodipine improves reinnervation and neuromuscular function after injury to the recurrent laryngeal nerve in the rat. Ann Otol Rhinol Laryngol 2007; 116: 623– 30 8 Strauss C, Bischoff B, Neu M, Berg M, Fahlbusch R, Romstoeck J. Vasoactive treatment for hearing preservation in acoustic neuroma surgery. J Neurosurg 2001; 95: 771– 7 9 Scheller C, Strauss C, Fahlbusch R, Romstoeck J. Delayed facial nerve paresis following acoustic neuroma resection and postoperative vasoactive treatment. Zentralbl Neurochir 2004; 65: 103–7 10 Strauss C, Romstoeck J, Fahlbusch R, Rampp S, Scheller C. Preservation of facial nerve function after postoperative vasoactive
doi:10.1093/bja/aet459
Reply from the authors Editor—We are grateful to Dr Scheller for his interest in our review.1 Dr Scheller has interestingly drawn our attention to one of his articles, where the effects of continuous infusion of nimodipine (15–30 mg kg21 h21), and hydroxyethylstarch 10% (aimed to maintain a hematocrit between 30% and 35%) started the day before surgery and continued until the seventh postoperative day, on facial nerve paresis and hearing loss after schwannoma surgery were tested.2 Dr Scheller suggests that his study should been included and described in our review. However, it was not for several reasons. (i) As reported in our ‘primary endpoints’, the selected studies should describe: new postoperative neurological deficit as stroke with the appearance of symptoms and/ or focal signs in the physical examination confirmed by computerized tomography imaging, or as a change in postoperative score from preoperative assessment with neurological scales such as the National Institutes of Health Stroke Scale (NIHSS) and the Western Perioperative Neurologic Scale (WPNS).1 Dr Scheller’s study was addressed to evaluate ‘cochlear and facial nerve function’ rather than symptoms or signs of brain damage. (ii) In our review, we describe ‘pharmacological perioperative brain neuroprotection’ and studies related to perioperative protection of cranial and spinal nerve function (that according to traditional anatomical categorization belong to the peripheral nervous system) were not selected.3 Of special interest, as reported in our review, nimodipine was tested in two randomized controlled trials—accomplished in cardiac surgery—with the aim of ‘Pharmacological perioperative brain neuroprotection’.4 5 One of these studies was prematurely aborted because of the unexpected disparity in death rates due to excess postoperative bleeding.5 This additional risk should be carefully considered in future studies with nimodipine.
179
Downloaded from http://bja.oxfordjournals.org/ at Belgorod State University on December 6, 2013
Declaration of interest
treatment in vestibular schwannoma surgery. Neurosurgery 2006; 59: 577– 84 11 Bischoff B, Romstoeck J, Fahlbusch R, Buchfelder M, Strauss C. Intraoperative brainstem auditory evoked potential pattern and perioperative vasoactive treatment for hearing preservation in vestibular schwannoma surgery. J Neurol Neurosurg Psychiatry 2008; 79: 170– 5 12 Scheller K, Scheller C. Nimodipine promotes regeneration of peripheral facial nerve function after traumatic injury following maxillofacial surgery: an off label pilot-study. J Craniomaxillofac Surg 2012; 40: 427–34, doi:10.1016/j.jcms.2011.07.016 13 Rabinstein AA, Lanzino G, Wijdicks EF. Multidisciplinary management and emerging therapeutic strategies in aneurysmal subarachnoid haemorrhage. Lancet Neurol 2010; 9: 504– 19, doi: 10.1016/S1474-4422(10)70087-9
