I read with interest the paper by Goodacre and Calvert.[1] I agree with
the authors that as most patients of undifferentiated chest pain have a
benign disorder, admission represents a considerable waste of resources.
Nevertheless, it is worrying to note that in UK 6% of patients discharged
from emergency departments after attendance with acute chest pain were
found to have prognostically significant myo...
I read with interest the paper by Goodacre and Calvert.[1] I agree with
the authors that as most patients of undifferentiated chest pain have a
benign disorder, admission represents a considerable waste of resources.
Nevertheless, it is worrying to note that in UK 6% of patients discharged
from emergency departments after attendance with acute chest pain were
found to have prognostically significant myocardial damage.[3]
Innovative action-plans, such as the introduction of chest pain
observation units
( CPOUs ) seem like a cost effective way for evaluating patients with
undifferentiated chest pain. CPOUs in the USA attempt to improve
diagnostic accuracy of acute coronary syndrome (ACS).[2] Patients are
subjected to a battery of tests, including an exercise ECG. If all these
tests are negative, the patient is sent home, but if the tests are
positive or equivocal, the patient is admitted for further
investigations.[2] In the UK, with much less interventional radiology and
higher discharge rates from the emergency departments, such a policy may
appear to be a non-starter.[2]
The district general hospitals may have to formalise a uniform
guideline so that they can risk stratify the cases of ACS effectively in a
CPOU as per Braunwald’s classification.[2] They will then be able to “fast
track” the highest of the high risk patients for further investigations
and thereby make the CPOU service most cost effective.
I agree with the authors that the diagnostic strategies for acute,
undifferentiated chest pain entailing observation and cardiac enzyme
testing and a definite on-site exercise testing will be the most cost
effective way forward and in this regard the paper by Goodacre and calvert
1 makes an useful contribution.. We can not compromise lives for not
including an exercise testing in the ‘plan’ if we have to follow a good
and safe practice strategy.
References
(1) Goodacre S, Calvert N. Cost effectiveness of diagnostic strategies
for patients with acute, undifferentiated chest pain. Emerg Med J 2003;
20: 429-33.
(2) Sinharay R. Cost-effective strategy to risk stratify acute chest
pain cases at a district general hospital. Postgrad Med J 2003; 79: 485.
(3) Collinson PO, Premchandran S, Hashemi K. Prospective audit of the
incidence of prognostically important myocardial damage in patients
discharged from emergency department. BMJ 2000; 320: 1702-05.
We read with interest the artlcle by Heath et al. in the Emergency
Medicine Journal, looking at nurse initiated thrombolysis in the accident
and emergency department.[1]
Speed of thrombolysis (and hence the "door
to needle" time) is well recognised as being important in reducing
myocardial damage and decreasing mortality in acute myocardial infarction.
In fact, "pain to needle" time is ev...
We read with interest the artlcle by Heath et al. in the Emergency
Medicine Journal, looking at nurse initiated thrombolysis in the accident
and emergency department.[1]
Speed of thrombolysis (and hence the "door
to needle" time) is well recognised as being important in reducing
myocardial damage and decreasing mortality in acute myocardial infarction.
In fact, "pain to needle" time is even more important with respect to
thrombolysis therapy, and a meta-analysis published in JAMA concluded that
prehospital thrombolysis for acute myocardial infarction significantly
decreased the time to thrombolysis and all-cause hospital mortality.[2]
We therefore suggest that it would be more beneficial to aim resources at
prehospital thrombolysis, rather than increasing the number of hospital
staff with the ability to thrombolise.[3,4]
We also wonder whether the authors have considered the fact that
reduction in time to thrombolysis in their study may have been due to the
time of day at which the acute chest pain nurse specialists were employed.
We note that they only were available for 62.5 hours per week, although
the actual shift times are not noted in the article. In the assumption
that these times were mainly during "office hours", some of the delay
during the out of hours fast track system may have been due to a general
lack of medical, nursing, portering staff or other facilities at these
times. Finally, such a new system would presumably have been well
publicised in relevant hospital departments, and improvements might be
explained by a Hawthorne-type effect.
References
(1) Heath et al. Nurse initiated thrombolysis in the accident and
emergency department: safe, accurate and faster than fast track. Emerg Med
J 2003; 20:418-420.
(2) Morrison et al. Mortality and prehospital thrombolysis for acute
myocardial infarction- A meta-analysis. JAMA 2000; 283:2686-2692.
(3) Pedley et al. Prospective observational cohort study of time saved by
prehospital thrombolysis for ST elevation myocardial infarction delivered
by paramedics. BMJ 2003; 327:22-26.
(4) Keeling et al. Safety and feasibility of prehospital thrombolysis
carried out by paramedics. BMJ 2003; 327:27-28
Kastner and Tagg have produced a useful guideline for the emergency
management of renal colic.[1] I would disagree however with their
recommendation that Pethidine 50 to 100mg should be administered if pain
is not relieved by combinations of NSAID and co-codamol or Tramadol. There
is no evidence that Pethidine has any specific advantages over other
opioids and the belief that it provides better analgesi...
Kastner and Tagg have produced a useful guideline for the emergency
management of renal colic.[1] I would disagree however with their
recommendation that Pethidine 50 to 100mg should be administered if pain
is not relieved by combinations of NSAID and co-codamol or Tramadol. There
is no evidence that Pethidine has any specific advantages over other
opioids and the belief that it provides better analgesia for colicky pain
than other opioids has not been substantiated.[2] It does however have a
toxic metabolite, norpethidine, which accumulates with multiple dosing and
in renal impairment.[3] In addition, at least one clinical trial has
shown no significant difference between morphine and pethidine in renal
colic managed in the Emergency Department.[4] Thus, in the absence of any
specific advantage of pethidine, there seems little justification for
including it in the guideline. My personal view is that if an opioid is
required, morphine or diamorphine should be used.[5]
References
1. Kastner C, Tagg A. Improving the effectiveness of the emergency
management of renal colic in a district general hospital: a completed
audit cycle. Emerg Med J 2003; 20: 449-450
2. McQuay H, Moore A, Justins D. Treating acute pain in hospital. BMJ
1997;314:1531-5
4. O'Connor A, Schug SA, Cardwell HA. Comparison of the efficacy and
safety of morphine and pethidine as analgesia for suspected renal colic in
the emergency setting. J Accid Emerg Med 2000; 17: 261-264
5. Mackenzie R. Analgesia and sedation. J R Army Med Corps 2000; 146:
117-127.
Since airbags were installed initially as a safety feature in
automobiles in
the early 1970s there has been a significant drop in severity of injuries arising out of motor vehicle collisions. Injuries to the eye in particular
have reduced since the introduction of laminated glass. Modern airbags
however have significant potential to cause serious permanent damage...
Since airbags were installed initially as a safety feature in
automobiles in
the early 1970s there has been a significant drop in severity of injuries arising out of motor vehicle collisions. Injuries to the eye in particular
have reduced since the introduction of laminated glass. Modern airbags
however have significant potential to cause serious permanent damage
to the eye from a number of mechanisms
1. Force of deployment
2. Situation of bags in steering wheel module and front driver side airbags
3. Driver positioning very close to steering wheel
4. Sodium hydroxide production as a byproduct of sodium azide
detonation [1,2] which is contained within the deployment mechanism of
the airbag itself.
These can result in physical damage to the ocular structures such as
abrasions or serious chemical injury from the alkalis produced.[3] The
alkalis cause a liquefactive necrosis and can result in permanent
blindness. Antosia [4] concluded that most injuries related to airbag
deployment are minor and must be viewed in context. I feel however
that the consequences of an alkali injury are such that emergency
department personnel should be educated with respect to examining,
recognising and treating urgently any patient presenting with decreased
vision post airbag deployment as a consequence of motor vehicle
collisions. I strongly concur with Wrigley and Blakeley in recommending
a careful eye examination in such cases. Airbags do provide significant
protection to the occupants of vehicles [5] but as with any intervention
we perform in the medical arena they must at first principles do no harm
References
1. Swanson-Biearman B et al. Air bags: lifesaving with toxic
potential? Am J Emerg Med, 1993. 11(1): p. 38-9.
2. White, J.E., et al. Ocular alkali burn associated with automobile
air-
bag activation. Cmaj, 1995. 153(7): p. 933-4.
3. Nordt, S.P., et al. Burns from automobile airbags. J Emerg Med,
2003. 25(2): p. 201-2.
4. Antosia, R.E., R.A. Partridge, and A.S. Virk, Air bag safety. Ann
Emerg Med, 1995. 25(6): p. 794-8.
5. Murphy, R.X.J., et al. The influence of airbag and restraining
devices on the patterns of facial trauma in motor vehicle collisions.
Plast
Reconstr Surg, 2000. 105(2): p. 516-20.
I agree with Dr Lockers concerns regarding the publication of BETS in
a peer reviewed journal. BETS are useful for introducing people to the
theory of literature searching, and appraisal of published evidence, ideal
skills for SPR's working towards their clinical topic review. However this
does not necessarily warrant their publication in a peer reviewed journal.
They occupy valuable space within a journal...
I agree with Dr Lockers concerns regarding the publication of BETS in
a peer reviewed journal. BETS are useful for introducing people to the
theory of literature searching, and appraisal of published evidence, ideal
skills for SPR's working towards their clinical topic review. However this
does not necessarily warrant their publication in a peer reviewed journal.
They occupy valuable space within a journal which is only published
bimonthly, which could instead be used by studies with more rigourous
methodology. If the EMJ is to become to be a leading worldwide journal in
the field of Emergency medicine, should it be including BETS within its
pages? I don't see the Lancet or the BMJ publishing 6-7 pages of medline
searches each edition.
Though Dr Hogg does explain that she has carried out a rigorous search,
and had this checked, this itself does deviate from the initial aims of
BETS as something a clinician could do in a short period of time.
With the advent of nearly universal internet use is the Best bets website
not the best place for them to reside?
On the 8th of this month, the large mutlicentre European
Resuscitation Council study comparing the effects of adrenaline and
vasopressin in out-of-hospital cardiac arrest was published. This was a
mutlicentre study conducted between 1999 and 2002 in Austria, Germany and
Switzerland. Patients with an out-of-hospital cardiac arrest requiring
cardiopulmonary resuscitation and intravenous vasopressor the...
On the 8th of this month, the large mutlicentre European
Resuscitation Council study comparing the effects of adrenaline and
vasopressin in out-of-hospital cardiac arrest was published. This was a
mutlicentre study conducted between 1999 and 2002 in Austria, Germany and
Switzerland. Patients with an out-of-hospital cardiac arrest requiring
cardiopulmonary resuscitation and intravenous vasopressor therapy were
included. The study shows no statistically significant benefit in primary
(overall survival to hospital) or secondary (overall survival to
discharge) end points. A subset analysis demonstrated that more patients
in asystolic arrest survived to hospital after the administration of
vasopressin as compared to adrenaline. Notably, the survival to discharge
did not reach clinical significance. The sub-analysis further
demonstrated that of those who did not respond to two doses of research
drug and went on to be administered adrenaline, significantly more
patients in the vasopressin group reached both end points.
This is the largest study addressing the question whether vasopressin
should be employed in an arrest. As normal practice, the Best BET
comparing these two entities has been updated to include this evidence.
We fully agree with the remarks made as to the use of morphine rather
than pethidine in patients with renal colic. During our investigations
primary pethidine was used in our institution and excursions about the use
of morphine were limited by the format of our publication. Therefore this
eletter is an extremely welcome contribution.
The following quote from the article is incorrect and misses the basic definition of power: "Strictly speaking 'power' refers to the number of patients required to avoid a type II error in a comparative study. Sample size estimation is a more encompassing term that looks at more than just the type II error and is applicable to all types of studies. In common parlance the terms are used interchangeably."
"Power" is the probability that the test correctly rejects the null hypothesis H0 when a specific alternative hypothesis H1 is true. It's equal to 1 - type II error probability. "Power" and "sample size" are not the same thing and they are not used interchangeably. It's possible to derive power given sample size, or calculate sample size based on desired power.
Please correct the article as it'll be highly misleading to beginners.
In an observational study where 200 participants were black, 269 asian, and 4330 white, the authors demonstrated an inverse association between blood pressure and pulse oximetry accuracy that was not influenced by ethnicity[1]. In that study no specific mention was made of the degree of pigmentation in individual members of the ethnic subgroups, presumable because self-reported ethnicity was accepted as a surrogate for skin colour. This acceptance is in sharp contrast with the methodology in the study where subjects of African-American descent were further characterised by a description of their degree of pigmentation, using terminology such as "very darkly pigmented".. This was one of the earliest prospective studies conclusively to show that some oximeters overestimate arterial oxygen saturation in hypoxic subjects who are "darkly pigmented" [2].
In retrospective studies such as the ones subsequently undertaken to explore the theme of racial bias in oximetry it was easy to fall into the trap of using ethnicity as a surrogate for skin colour[3],[4], largely because skin colour is not consistently recorded as part of the medical record[3]. Explicit description of skin colour also gets omitted when race and ethnicity are defined using self-reported demographic data[4].
Future studies, however, might seek to ascertain whether or not skin pigmentation compounds the overestimation of oxygen saturation attributable to hypotension....
In an observational study where 200 participants were black, 269 asian, and 4330 white, the authors demonstrated an inverse association between blood pressure and pulse oximetry accuracy that was not influenced by ethnicity[1]. In that study no specific mention was made of the degree of pigmentation in individual members of the ethnic subgroups, presumable because self-reported ethnicity was accepted as a surrogate for skin colour. This acceptance is in sharp contrast with the methodology in the study where subjects of African-American descent were further characterised by a description of their degree of pigmentation, using terminology such as "very darkly pigmented".. This was one of the earliest prospective studies conclusively to show that some oximeters overestimate arterial oxygen saturation in hypoxic subjects who are "darkly pigmented" [2].
In retrospective studies such as the ones subsequently undertaken to explore the theme of racial bias in oximetry it was easy to fall into the trap of using ethnicity as a surrogate for skin colour[3],[4], largely because skin colour is not consistently recorded as part of the medical record[3]. Explicit description of skin colour also gets omitted when race and ethnicity are defined using self-reported demographic data[4].
Future studies, however, might seek to ascertain whether or not skin pigmentation compounds the overestimation of oxygen saturation attributable to hypotension. For those studies to be scientifically robust explicit documentation of the degree of pigmentation will have to be made., using, for example, strategies such as the Melasma Area and Severity Index[5], and the Willis and Earle scale[6], to mention a few.
I have no funding and no conflict of interest
References
[1]Crooks CJ., West J., Morling J et al
Inverse association between blood pressure and pulse oximetry accuracy: an observational study in patients with suspected or confirmed COVID-19 infection
Emergency Medical Journal Article in Press
doi:10.1136/emermed-2022-212443
[2]Bickler PE., Feiner JR., Severinghaus SW
Effects of skin pigmentation on pulse oximeter accuracy at low saturation
Anesthesiology 2005;102:715-719
[3]Valbuena VSM., Seelye S., Sjoding MW et al
Racial bias and reproducibility in pulse oximetry among medical and surgical inpatients in general care in Veterans Administration 2013-19: multicenter retrospective cohort study
BMJ 2022;378:e069775
[4]Wong A-K I., Charpignon M., Kim H et al
Analysis of discrepancies between pulse oximetry and arterisl oxygen saturation measurements by race and ethnicity and association with organ dysfunction and mortality
JAMA Netweork OPEN 2021;4:e2131674
[5]Pandya AG., Hynan LS., Bhore R et al
Reliability assessment and validation of the Melasma Area and Severity Index(MASI) and a new modified MASI scoring method
J Am Acad Dermatol 2011;64:78-83
[6]Roberts W
Skin type classification systems old and new
Dermatology Clinics 2009;27:529-533
We thank Dr. Delaney and colleagues for their valuable research into the concept of midline cervical tenderness. Unlike the NEXUS critiera, the Canadian C-Spine Rule does not use midline tenderness as a positive indication for imaging. Our original study in JAMA 2001 found that assessment of this criterion amongst alert trauma patients at risk of c-spine tenderness had excellent interobserver agreement between ED physicians with a kappa of 0.78. We found that absence of midline tenderness was a good negative predictor of c-spine injury but that presence of of such tenderness was non-specific and not useful. Hence, absence of midline tenderness is considered a low-risk factor. Our NEJM 2003 validation study found that the CCR had both better sensitivity and specificity than NEXUS.
Best regards
1. Stiell IG, Wells GA, Vandemheen K, Clement C, Lesiuk H, De Maio VJ et al. The Canadian Cervical Spine Radiography Rule for alert and stable trauma patients. JAMA 2001; 286(15):1841-1848.
2. Stiell IG, Clement C, McKnight RD, Brison R, Schull MJ, Rowe BH et al. The Canadian C-spine Rule versus the NEXUS low-risk criteria in patients with trauma. N Engl J Med 2003; 349:2510-2518.
Dear Editor
I read with interest the paper by Goodacre and Calvert.[1] I agree with the authors that as most patients of undifferentiated chest pain have a benign disorder, admission represents a considerable waste of resources. Nevertheless, it is worrying to note that in UK 6% of patients discharged from emergency departments after attendance with acute chest pain were found to have prognostically significant myo...
Dear Editor
We read with interest the artlcle by Heath et al. in the Emergency Medicine Journal, looking at nurse initiated thrombolysis in the accident and emergency department.[1]
Speed of thrombolysis (and hence the "door to needle" time) is well recognised as being important in reducing myocardial damage and decreasing mortality in acute myocardial infarction. In fact, "pain to needle" time is ev...
Dear Editor
Kastner and Tagg have produced a useful guideline for the emergency management of renal colic.[1] I would disagree however with their recommendation that Pethidine 50 to 100mg should be administered if pain is not relieved by combinations of NSAID and co-codamol or Tramadol. There is no evidence that Pethidine has any specific advantages over other opioids and the belief that it provides better analgesi...
Dear Editor
Air Bags-Primum non nocere
Since airbags were installed initially as a safety feature in automobiles in the early 1970s there has been a significant drop in severity of injuries arising out of motor vehicle collisions. Injuries to the eye in particular have reduced since the introduction of laminated glass. Modern airbags however have significant potential to cause serious permanent damage...
Dear Editor
I agree with Dr Lockers concerns regarding the publication of BETS in a peer reviewed journal. BETS are useful for introducing people to the theory of literature searching, and appraisal of published evidence, ideal skills for SPR's working towards their clinical topic review. However this does not necessarily warrant their publication in a peer reviewed journal. They occupy valuable space within a journal...
Dear Editor
On the 8th of this month, the large mutlicentre European Resuscitation Council study comparing the effects of adrenaline and vasopressin in out-of-hospital cardiac arrest was published. This was a mutlicentre study conducted between 1999 and 2002 in Austria, Germany and Switzerland. Patients with an out-of-hospital cardiac arrest requiring cardiopulmonary resuscitation and intravenous vasopressor the...
Dear Editor
We fully agree with the remarks made as to the use of morphine rather than pethidine in patients with renal colic. During our investigations primary pethidine was used in our institution and excursions about the use of morphine were limited by the format of our publication. Therefore this eletter is an extremely welcome contribution.
Thank you very much.
The following quote from the article is incorrect and misses the basic definition of power: "Strictly speaking 'power' refers to the number of patients required to avoid a type II error in a comparative study. Sample size estimation is a more encompassing term that looks at more than just the type II error and is applicable to all types of studies. In common parlance the terms are used interchangeably."
"Power" is the probability that the test correctly rejects the null hypothesis H0 when a specific alternative hypothesis H1 is true. It's equal to 1 - type II error probability. "Power" and "sample size" are not the same thing and they are not used interchangeably. It's possible to derive power given sample size, or calculate sample size based on desired power.
Please correct the article as it'll be highly misleading to beginners.
In an observational study where 200 participants were black, 269 asian, and 4330 white, the authors demonstrated an inverse association between blood pressure and pulse oximetry accuracy that was not influenced by ethnicity[1]. In that study no specific mention was made of the degree of pigmentation in individual members of the ethnic subgroups, presumable because self-reported ethnicity was accepted as a surrogate for skin colour. This acceptance is in sharp contrast with the methodology in the study where subjects of African-American descent were further characterised by a description of their degree of pigmentation, using terminology such as "very darkly pigmented".. This was one of the earliest prospective studies conclusively to show that some oximeters overestimate arterial oxygen saturation in hypoxic subjects who are "darkly pigmented" [2].
Show MoreIn retrospective studies such as the ones subsequently undertaken to explore the theme of racial bias in oximetry it was easy to fall into the trap of using ethnicity as a surrogate for skin colour[3],[4], largely because skin colour is not consistently recorded as part of the medical record[3]. Explicit description of skin colour also gets omitted when race and ethnicity are defined using self-reported demographic data[4].
Future studies, however, might seek to ascertain whether or not skin pigmentation compounds the overestimation of oxygen saturation attributable to hypotension....
We thank Dr. Delaney and colleagues for their valuable research into the concept of midline cervical tenderness. Unlike the NEXUS critiera, the Canadian C-Spine Rule does not use midline tenderness as a positive indication for imaging. Our original study in JAMA 2001 found that assessment of this criterion amongst alert trauma patients at risk of c-spine tenderness had excellent interobserver agreement between ED physicians with a kappa of 0.78. We found that absence of midline tenderness was a good negative predictor of c-spine injury but that presence of of such tenderness was non-specific and not useful. Hence, absence of midline tenderness is considered a low-risk factor. Our NEJM 2003 validation study found that the CCR had both better sensitivity and specificity than NEXUS.
Best regards
1. Stiell IG, Wells GA, Vandemheen K, Clement C, Lesiuk H, De Maio VJ et al. The Canadian Cervical Spine Radiography Rule for alert and stable trauma patients. JAMA 2001; 286(15):1841-1848.
2. Stiell IG, Clement C, McKnight RD, Brison R, Schull MJ, Rowe BH et al. The Canadian C-spine Rule versus the NEXUS low-risk criteria in patients with trauma. N Engl J Med 2003; 349:2510-2518.
Pages