E Letters to the Editor In Response
W
e did not encounter the unstable noninvasive hemoglobin described by Kalmar et al.1 probably because we applied the probe after induction of anesthesia with a constant fraction of inspired oxygen, and baseline confirmation of actual Hb was performed just before surgical incision.2 We agree with Kalmar et al.1 that appropriate timing of the determination of the baseline value is important. We can obtain more accurate information if we apply the probe and confirm real Hb during stable conditions as described above. In addition, while we agree that it is advisable to recheck the reference value after major changes in hemodynamic and/ or ventilatory conditions, too frequent confirmation of actual Hb seems impractical, and therefore, the frequency should be determined considering both the accuracy and practicability.
(the sum of hydrostatic and oncotic pressure gradients). Therefore, unpredictably, the SpHb may under- or overestimate arterial Hb, and ideally, this can be considered in future versions of the device. In summary, in our study, we were aware of the differences cited by Kalmar et al. but wanted to determine whether trend values generated by the noninvasive device could be used for volume kinetic analysis. Our conclusion was that, in the particular setting presented, the technology was helpful. Fredrik Sjöstrand, MD, PhD Department of Clinical Science & Education Section of Emergency Medicine Karolinska Institutet Department of Emergency Medicine Södersjukhuset AB Stockholm, Sweden [email protected]
Yong-Hee Park, MD Jin-Tae Kim, MD, PhD Department of Anesthesiology and Pain Medicine Seoul National University Hospital Seoul, Korea [email protected] REFERENCES 1. Kalmar AF, Poterman M, Scheeren TW. Periopeative calibration of noninvasive hemoglobin monitoring. Anesth Analg 2014;118:481 2. Park YH, Lee JH, Song HG, Byon HJ, Kim HS, Kim JT. The accuracy of noninvasive hemoglobin monitoring using the radical-7 pulse CO-Oximeter in children undergoing neurosurgery. Anesth Analg 2012;115:1302–7 Copyright © 2014 the authors. DOI: 10.1213/ANE.0000000000000029
In Response
W
e agree with Kalmar et al.1 that the noninvasive hemoglobin determination (SpHb) generated by the device may not be precise enough for single hemoglobin values as compared with those obtained using invasive measures. However, because trends are of interest when focusing on volume kinetic models, our conclusion was that the SpHb device could be useful for this purpose.2 We also agree with Kalmar et al.1 that the baseline Hb measurement is of interest and that minor and major shifts in the baseline do occur. One area of interest is to better understand changes in the perfusion index. Following is a brief description of how we view the physiological issues and challenges ahead. The SpHb measured by the Radical-7 device is based on multi-wavelength light absorption of hemoglobin in capillaries under the nail. The deviation of SpHb from arterial Hb is therefore multifactorial and depends on the Fåhreus effect, transcapillary fluid filtration absorption ratio, vasomotor tone (reflected by the perfusion index), and ambient temperature. The difference between arterial Hb and Hb in larger capillaries is relatively stable since it depends solely on the Fåhreus effect. However, this difference in the smallest capillaries is dynamic since it depends on the transcapillary fluid filtration absorption ratio, which in turn is affected by multiple factors, for example, changes in interstitial fluid compliance and net transcapillary pressure
482 www.anesthesia-analgesia.org
Christer Svensen, MD, PhD Department of Clinical Science & Education Section of Anesthesiology and Intensive Care Karolinska Institutet Södersjukhuset Stockholm, Sweden REFERENCES 1. Kalmar AF, Poterman M, Scheeren TWL. Perioperative calibration of noninvasive hemoglobin monitoring. Anesth Analg 2014;118:481 2. Sjöstrand F, Rodhe P, Berglund E, Lundström N, Svensen C. The use of a noninvasive hemoglobin monitor for volume kinetic analysis in an emergency room setting. Anesth Analg 2013;116:337–42 Copyright © 2014 the authors. DOI: 10.1213/ANE.0000000000000034
Anesthesiology Resident Burnout–An Irish Perspective To the Editor
T
he recent article by de Oliveira et al.1 provides some insight into the prevalence of burnout and depression among anesthesiology residents in the United States. We would like to share our experience with this problem in Ireland. We conducted a survey of all anesthesiology residents in Ireland to determine the impact and sources of stress in their working lives. Our findings mirror many of those highlighted by de Oliveira et al.1 We received 39 responses in our national survey of residents (termed specialist registrars) in anesthesia, equating to a 55% response rate. This is comparable with the response rate in the survey of U.S. residents. Eightyseven percent of the trainees reported work in excess of 48 hours per week. Interestingly, 51% of those who replied to the survey felt that they worked excessively long hours. Most respondents (79%) felt that pressure at work had affected their health and that work-related stress caused them to perform less well “sometimes”
anesthesia & analgesia
Letters to the Editor
(50%) or “often” (10%), and 42% often come to work when they are not well enough to work. Eighty-six percent of respondents replied “sometimes” or “never” when asked if they could talk to someone at work if they felt they were under excessive pressure. Concern regarding training doctors’ working hours and the consequent impact on patient care and physician health has recently received much media attention in Ireland.2 There is disquiet in the medical profession in Ireland at the fact that residents there continue to work outside the limits defined as acceptable by the European Working Time Directive.3 This legislation limits the hours a doctor should work to 48 hours per week. Anesthesiology residents in Ireland routinely work shifts in excess of 24 hours, and in some other specialties, shifts can extend to 36 hours. In the move for reform, emphasis is being placed on enforcing a maximum shift period of 24 hours rather than reducing to a 48-hour working week per se. This issue has escalated in importance in the last year, and the trade union representing residents in Ireland will soon ask members to vote on whether to proceed to strike action in protest against what are felt to be unsustainable work patterns. It has been well demonstrated that prolonged periods of continual wakefulness result in impaired concentration and motor skills.4 Twenty-four hours without sleep impairs the ability to perform certain cognitive tasks to the same degree as that from a blood alcohol level of 100 mg/dL.5 Fatigue in residents is associated with reduced vigilance and in 1 study was associated with impaired ability to detect significant changes in clinical variables when monitoring patients in simulated scenarios.6 Given these proven negative effects of fatigue on cognition, it seems intuitive that trying to introduce measures to prevent chronic sleep deprivation in residents would be in the interest of patient safety. Studies have looked at establishing a link between doctor fatigue and negative patient outcomes. This work relies predominantly on self-reporting of errors and retrospective data with respondents consistently reporting an association between medical errors and doctor fatigue.7 The best available evidence demonstrates that the incidence of serious medical errors committed by critical care interns increased by 36% when working >24 hours vs a maximum shift length of 16 hours.8 It is possible however that shortening resident shifts and more frequent personnel changes introduces a lack of continuity of care, and in turn increases the likelihood of medical mistakes. There is evidence to suggest that cross-coverage (care by a trainee doctor who was not on the patients’ primary care team) is associated with an increased adverse event rate. However, there has been increased awareness of this potential problem in recent years, and research has been performed on interventions to prevent errors due to inadequate handover during resident shift changes. It has also been shown that a structured handover process is an effective tool in preventing handover errors and improving patient safety.9 In summary, we would question whether there is still justification for working shifts in excess of 24 hours, particularly in high acuity specialties such as anesthesia. We
February 2014 • Volume 118 • Number 2
welcome the attention that your recently published article casts on the matter. Abigail M. Walsh, MB, BMedSci, MRCP, FCARCSI Department of Anesthesia and Intensive Care Medicine Mercy University Hospital Cork, Ireland [email protected] Denise McCarthy, MB, FCARCSI Kamran Ghori, MBBS, FCARCSI, MD Department of Anesthesia Bons Secours Hospital Cork, Ireland REFERENCES 1. de Oliveira GS Jr, Chang R, Fitzgerald PC, Almeida MD, CastroAlves LS, Ahmad S, McCarthy RJ. The prevalence of burnout and depression and their association with adherence to safety and practice standards: a survey of United States anesthesiology trainees. Anesth Analg 2013;117:182–93 2. Doctors to Ballot for industrial action over hours. The Irish Times 2013 3. Directive 2003/88/EC of the European Parliament and of the Council of 4 November 2003 concerning certain aspects of the organisation of working time. Official Journal of the European Union. 2003;L 299:9–19 4. Howard SK, Gaba DM, Smith BE, Weinger MB, Herndon C, Keshavacharya S, Rosekind MR. Simulation study of rested versus sleep-deprived anesthesiologists. Anesthesiology 2003;98:1345–55 5. Williamson AM, Feyer AM. Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occup Environ Med 2000;57:649–55 6. Denisco RA, Drummond JN, Gravenstein JS. The effect of fatigue on the performance of a simulated anesthetic monitoring task. J Clin Monit 1987;3:22–4 7. Morris GP, Morris RW. Anaesthesia and fatigue: an analysis of the first 10 years of the Australian Incident Monitoring Study 1987-1997. Anaesth Intensive Care 2000;28:300–4 8. Landrigan CP, Rothschild JM, Cronin JW, Kaushal R, Burdick E, Katz JT, Lilly CM, Stone PH, Lockley SW, Bates DW, Czeisler CA. Effect of reducing interns’ work hours on serious medical errors in intensive care units. N Engl J Med 2004;351:1838–48 9. Agarwal HS, Saville BR, Slayton JM, Donahue BS, Daves S, Christian KG, Bichell DP, Harris ZL. Standardized postoperative handover process improves outcomes in the intensive care unit: a model for operational sustainability and improved team performance*. Crit Care Med 2012;40:2109–15 Copyright © 2014 the authors. DOI: 10.1213/ANE.0000000000000037
In Response
M
y thanks to Walsh et al.1 for sharing their experience on work-related stress of anesthesiology trainees in Ireland. It is particularly interesting that 79% of residents stated that pressure at work had affected their health and that work-related stress caused them to perform suboptimally despite working far fewer hours per week compared with the workload of anesthesiology trainees in the United States.1 Resident burnout may also influence resident perceived supervision that has also been associated with increased medical errors.2–5 And finally, burnout may also result in residents becoming less engaged in educational activities and research.6
www.anesthesia-analgesia.org
483
W
e did not encounter the unstable noninvasive hemoglobin described by Kalmar et al.1 probably because we applied the probe after induction of anesthesia with a constant fraction of inspired oxygen, and baseline confirmation of actual Hb was performed just before surgical incision.2 We agree with Kalmar et al.1 that appropriate timing of the determination of the baseline value is important. We can obtain more accurate information if we apply the probe and confirm real Hb during stable conditions as described above. In addition, while we agree that it is advisable to recheck the reference value after major changes in hemodynamic and/ or ventilatory conditions, too frequent confirmation of actual Hb seems impractical, and therefore, the frequency should be determined considering both the accuracy and practicability.
(the sum of hydrostatic and oncotic pressure gradients). Therefore, unpredictably, the SpHb may under- or overestimate arterial Hb, and ideally, this can be considered in future versions of the device. In summary, in our study, we were aware of the differences cited by Kalmar et al. but wanted to determine whether trend values generated by the noninvasive device could be used for volume kinetic analysis. Our conclusion was that, in the particular setting presented, the technology was helpful. Fredrik Sjöstrand, MD, PhD Department of Clinical Science & Education Section of Emergency Medicine Karolinska Institutet Department of Emergency Medicine Södersjukhuset AB Stockholm, Sweden [email protected]
Yong-Hee Park, MD Jin-Tae Kim, MD, PhD Department of Anesthesiology and Pain Medicine Seoul National University Hospital Seoul, Korea [email protected] REFERENCES 1. Kalmar AF, Poterman M, Scheeren TW. Periopeative calibration of noninvasive hemoglobin monitoring. Anesth Analg 2014;118:481 2. Park YH, Lee JH, Song HG, Byon HJ, Kim HS, Kim JT. The accuracy of noninvasive hemoglobin monitoring using the radical-7 pulse CO-Oximeter in children undergoing neurosurgery. Anesth Analg 2012;115:1302–7 Copyright © 2014 the authors. DOI: 10.1213/ANE.0000000000000029
In Response
W
e agree with Kalmar et al.1 that the noninvasive hemoglobin determination (SpHb) generated by the device may not be precise enough for single hemoglobin values as compared with those obtained using invasive measures. However, because trends are of interest when focusing on volume kinetic models, our conclusion was that the SpHb device could be useful for this purpose.2 We also agree with Kalmar et al.1 that the baseline Hb measurement is of interest and that minor and major shifts in the baseline do occur. One area of interest is to better understand changes in the perfusion index. Following is a brief description of how we view the physiological issues and challenges ahead. The SpHb measured by the Radical-7 device is based on multi-wavelength light absorption of hemoglobin in capillaries under the nail. The deviation of SpHb from arterial Hb is therefore multifactorial and depends on the Fåhreus effect, transcapillary fluid filtration absorption ratio, vasomotor tone (reflected by the perfusion index), and ambient temperature. The difference between arterial Hb and Hb in larger capillaries is relatively stable since it depends solely on the Fåhreus effect. However, this difference in the smallest capillaries is dynamic since it depends on the transcapillary fluid filtration absorption ratio, which in turn is affected by multiple factors, for example, changes in interstitial fluid compliance and net transcapillary pressure
482 www.anesthesia-analgesia.org
Christer Svensen, MD, PhD Department of Clinical Science & Education Section of Anesthesiology and Intensive Care Karolinska Institutet Södersjukhuset Stockholm, Sweden REFERENCES 1. Kalmar AF, Poterman M, Scheeren TWL. Perioperative calibration of noninvasive hemoglobin monitoring. Anesth Analg 2014;118:481 2. Sjöstrand F, Rodhe P, Berglund E, Lundström N, Svensen C. The use of a noninvasive hemoglobin monitor for volume kinetic analysis in an emergency room setting. Anesth Analg 2013;116:337–42 Copyright © 2014 the authors. DOI: 10.1213/ANE.0000000000000034
Anesthesiology Resident Burnout–An Irish Perspective To the Editor
T
he recent article by de Oliveira et al.1 provides some insight into the prevalence of burnout and depression among anesthesiology residents in the United States. We would like to share our experience with this problem in Ireland. We conducted a survey of all anesthesiology residents in Ireland to determine the impact and sources of stress in their working lives. Our findings mirror many of those highlighted by de Oliveira et al.1 We received 39 responses in our national survey of residents (termed specialist registrars) in anesthesia, equating to a 55% response rate. This is comparable with the response rate in the survey of U.S. residents. Eightyseven percent of the trainees reported work in excess of 48 hours per week. Interestingly, 51% of those who replied to the survey felt that they worked excessively long hours. Most respondents (79%) felt that pressure at work had affected their health and that work-related stress caused them to perform less well “sometimes”
anesthesia & analgesia
Letters to the Editor
(50%) or “often” (10%), and 42% often come to work when they are not well enough to work. Eighty-six percent of respondents replied “sometimes” or “never” when asked if they could talk to someone at work if they felt they were under excessive pressure. Concern regarding training doctors’ working hours and the consequent impact on patient care and physician health has recently received much media attention in Ireland.2 There is disquiet in the medical profession in Ireland at the fact that residents there continue to work outside the limits defined as acceptable by the European Working Time Directive.3 This legislation limits the hours a doctor should work to 48 hours per week. Anesthesiology residents in Ireland routinely work shifts in excess of 24 hours, and in some other specialties, shifts can extend to 36 hours. In the move for reform, emphasis is being placed on enforcing a maximum shift period of 24 hours rather than reducing to a 48-hour working week per se. This issue has escalated in importance in the last year, and the trade union representing residents in Ireland will soon ask members to vote on whether to proceed to strike action in protest against what are felt to be unsustainable work patterns. It has been well demonstrated that prolonged periods of continual wakefulness result in impaired concentration and motor skills.4 Twenty-four hours without sleep impairs the ability to perform certain cognitive tasks to the same degree as that from a blood alcohol level of 100 mg/dL.5 Fatigue in residents is associated with reduced vigilance and in 1 study was associated with impaired ability to detect significant changes in clinical variables when monitoring patients in simulated scenarios.6 Given these proven negative effects of fatigue on cognition, it seems intuitive that trying to introduce measures to prevent chronic sleep deprivation in residents would be in the interest of patient safety. Studies have looked at establishing a link between doctor fatigue and negative patient outcomes. This work relies predominantly on self-reporting of errors and retrospective data with respondents consistently reporting an association between medical errors and doctor fatigue.7 The best available evidence demonstrates that the incidence of serious medical errors committed by critical care interns increased by 36% when working >24 hours vs a maximum shift length of 16 hours.8 It is possible however that shortening resident shifts and more frequent personnel changes introduces a lack of continuity of care, and in turn increases the likelihood of medical mistakes. There is evidence to suggest that cross-coverage (care by a trainee doctor who was not on the patients’ primary care team) is associated with an increased adverse event rate. However, there has been increased awareness of this potential problem in recent years, and research has been performed on interventions to prevent errors due to inadequate handover during resident shift changes. It has also been shown that a structured handover process is an effective tool in preventing handover errors and improving patient safety.9 In summary, we would question whether there is still justification for working shifts in excess of 24 hours, particularly in high acuity specialties such as anesthesia. We
February 2014 • Volume 118 • Number 2
welcome the attention that your recently published article casts on the matter. Abigail M. Walsh, MB, BMedSci, MRCP, FCARCSI Department of Anesthesia and Intensive Care Medicine Mercy University Hospital Cork, Ireland [email protected] Denise McCarthy, MB, FCARCSI Kamran Ghori, MBBS, FCARCSI, MD Department of Anesthesia Bons Secours Hospital Cork, Ireland REFERENCES 1. de Oliveira GS Jr, Chang R, Fitzgerald PC, Almeida MD, CastroAlves LS, Ahmad S, McCarthy RJ. The prevalence of burnout and depression and their association with adherence to safety and practice standards: a survey of United States anesthesiology trainees. Anesth Analg 2013;117:182–93 2. Doctors to Ballot for industrial action over hours. The Irish Times 2013 3. Directive 2003/88/EC of the European Parliament and of the Council of 4 November 2003 concerning certain aspects of the organisation of working time. Official Journal of the European Union. 2003;L 299:9–19 4. Howard SK, Gaba DM, Smith BE, Weinger MB, Herndon C, Keshavacharya S, Rosekind MR. Simulation study of rested versus sleep-deprived anesthesiologists. Anesthesiology 2003;98:1345–55 5. Williamson AM, Feyer AM. Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occup Environ Med 2000;57:649–55 6. Denisco RA, Drummond JN, Gravenstein JS. The effect of fatigue on the performance of a simulated anesthetic monitoring task. J Clin Monit 1987;3:22–4 7. Morris GP, Morris RW. Anaesthesia and fatigue: an analysis of the first 10 years of the Australian Incident Monitoring Study 1987-1997. Anaesth Intensive Care 2000;28:300–4 8. Landrigan CP, Rothschild JM, Cronin JW, Kaushal R, Burdick E, Katz JT, Lilly CM, Stone PH, Lockley SW, Bates DW, Czeisler CA. Effect of reducing interns’ work hours on serious medical errors in intensive care units. N Engl J Med 2004;351:1838–48 9. Agarwal HS, Saville BR, Slayton JM, Donahue BS, Daves S, Christian KG, Bichell DP, Harris ZL. Standardized postoperative handover process improves outcomes in the intensive care unit: a model for operational sustainability and improved team performance*. Crit Care Med 2012;40:2109–15 Copyright © 2014 the authors. DOI: 10.1213/ANE.0000000000000037
In Response
M
y thanks to Walsh et al.1 for sharing their experience on work-related stress of anesthesiology trainees in Ireland. It is particularly interesting that 79% of residents stated that pressure at work had affected their health and that work-related stress caused them to perform suboptimally despite working far fewer hours per week compared with the workload of anesthesiology trainees in the United States.1 Resident burnout may also influence resident perceived supervision that has also been associated with increased medical errors.2–5 And finally, burnout may also result in residents becoming less engaged in educational activities and research.6
www.anesthesia-analgesia.org
483
