Category Archives: Kids

Acute Paediatrics

Acute Med, All Updates, ICU, Kids, PHARM, Resus, Trauma

Capillary refill time

A review of capillary refill time (CRT) reveals some interesting details about this test:

  • CRT is affected by age – the upper limit of normal for neonates is 3 seconds.
  • It increases with age – one study recommended the upper limit of normal for adult women should be increased to 2.9 seconds and for the elderly to 4.5 seconds.
  • It is affected by multiple external factors (especially ambient temperature).
  • Although it is claimed to have some predictive value in the assessment of dehydration and serious infection in children, studies vary in where and for how long pressure should be applied, and there is poor interobserver reliability.

The latest (5th Edition) of the Advanced Paediatric Life Support Manual states:
‘Poor capillary refill and differential pulse volumes are neither sensitive nor specific indicators of shock in infants and children, but are useful clinical signs when used in conjunction with the other signs described‘
In my view, it is best used as a monitor of trends (in accordance with skin temperature and other markers of perfusion), rather than by placing emphasis on the exact number of seconds of a single reading. See below for a video of my perfectly happy and healthy son demonstrating a CRT of over six seconds in a cool room during an English Summer’s day.
The authors of the review caution:
Operating rooms are cold, patients are often draped, which limits access, and because most anesthetics are potent vasodilators, the use of CRT to guide practice is not justified. The possibility of a false-positive or false-negative assessment is simply too great.


Capillary refill time (CRT) is widely used by health care workers as part of the rapid, structured cardiopulmonary assessment of critically ill patients. Measurement involves the visual inspection of blood returning to distal capillaries after they have been emptied by pressure. It is hypothesized that CRT is a simple measure of alterations in peripheral perfusion. Evidence for the use of CRT in anesthesia is lacking and further research is required, but understanding may be gained from evidence in other fields. In this report, we examine this evidence and factors affecting CRT measurement. Novel approaches to the assessment of CRT are under investigation. In the future, CRT measurement may be achieved using new technologies such as digital videography or modified oxygen saturation probes; these new methods would remove the limitations associated with clinical CRT measurement and may even be able to provide an automated CRT measurement.

Capillary Refill Time: Is It Still a Useful Clinical Sign?
Anesth Analg. 2011 Jul;113(1):120-3
The Capillary Refill Video

Acute Med, All Updates, ICU, Kids, Resus

Why I don't give vasopressors in sepsis

Leave a comment

It’s become popular to use the term ‘vasopressors’ or just ‘pressors’ when noradrenaline/norepinephrine or even (in some places still) dopamine are given. I have resisted this trend and continue to use the term ‘vasoactive’ drugs, on the basis that the effects they produce (and that we may desire) are not limited to a pure alpha adrenergic effect on vascular tone, but they have effects on heart rate and contractility too (as well as preload through venous effects). If you don’t believe me about noradrenaline/norepinephrine, then check out one of my favourite critical care papers of all time: the CAT study.
There are of course real pressors out there – phenylephrine acts on alpha receptors, as does methoxamine. Metaraminol predominantly acts on alpha receptors but does also cause some release of noradrenaline/norepinephrine.
Why is this important? All these drugs will fix hypotension, right? Yes, they should. However should blood pressure be our main treatment goal? What we’re really interested in is organ perfusion, which depends on regional blood flow to vital organs. It’s possible that a drug could fix the measured blood pressure and give a nice ‘macroscopic’ number, while at the same time reducing cardiac output and adversely affecting regional blood flow to organs through local vasoconstrictive effects. My view is that this is more likely with pure ‘pressors’ (like phenylephrine), which is why I avoid them in septic shock and opt for catecholamine infusions (noradrenaline/norepinephrine).
This is important in my practice setting of retrieval medicine, where, prior to interfacility transport, physicians might sometimes be tempted to ‘push pressors’ peripherally rather than insert a central venous catheter and commence a catecholamine infusion. While the former approach might be more expeditious and make the vital signs chart look pretty, one wonders about what effect this is having on tissue oxygen delivery.
A fascinating review of papers on pressor physiology1 suggests these agents have the following effects:

  • conflicting data on changes in myocardial perfusion
  • increase both left and right heart afterload
  • decrease venous compliance with the potential to increase venous return although the impact of this on cardiac output is controversial
  • controversial effect on cerebral bloodflow
  • decrease bloodflow to the kidneys
  • adverse affects on gastrointestinal tract bloodflow


abstract1
Phenylephrine and methoxamine are direct-acting, predominantly α(1) adrenergic receptor (AR) agonists. To better understand their physiologic effects, we screened 463 articles on the basis of PubMed searches of “methoxamine” and “phenylephrine” (limited to human, randomized studies published in English), as well as citations found therein. Relevant articles, as well as those discovered in the peer-review process, were incorporated into this review. Both methoxamine and phenylephrine increase cardiac afterload via several mechanisms, including increased vascular resistance, decreased vascular compliance, and disadvantageous alterations in the pressure waveforms produced by the pulsatile heart. Although pure α(1) agonists increase arterial blood pressure, neither animal nor human studies have ever shown pure α(1)-agonism to produce a favorable change in myocardial energetics because of the resultant increase in myocardial workload. Furthermore, the cost of increased blood pressure after pure α(1)-agonism is almost invariably decreased cardiac output, likely due to increases in venous resistance. The venous system contains α(1) ARs, and though stimulation of α(1) ARs decreases capacitance and may transiently increase venous return, this gain may be offset by changes in afterload, venous compliance, and venous resistance. Data on the effects of α(1) stimulation in the central nervous system show conflicting changes, while experimental animal data suggest that renal blood flow is reduced by α(1)-agonists, and both animal and human data suggest that gastrointestinal perfusion may be reduced by α(1) tone.

A review of clinical articles2 reveals few evidence-based indications for true pressors. Possible situations where they may be of benefit include intraoperative hypotension, aortic stenosis, during cyanotic episodes in Tetralogy of Fallot, and some obstetric situations. In the setting of sepis, phenylephrine has been compared with noradrenaline in which an initial pilot study found a statistically significant reduction in creatinine clearance and increase in arterial lactate after initiating the phenylephrine infusion. However a subsequent randomised controlled comparison of phenylephrine with noradrenaline/norepinephrine did not show differences in cardiopulmonary performance, global oxygen transport, or regional hemodynamics, although there were only 16 patients in each group3.


abstract2
Phenylephrine is a direct-acting, predominantly α(1) adrenergic receptor agonist used by anesthesiologists and intensivists to treat hypotension. A variety of physiologic studies suggest that α-agonists increase cardiac afterload, reduce venous compliance, and reduce renal bloodflow. The effects on gastrointestinal and cerebral perfusion are controversial. To better understand the effects of phenylephrine in a variety of clinical settings, we screened 463 articles on the basis of PubMed searches of “methoxamine,” a long-acting α agonist, and “phenylephrine” (limited to human, randomized studies published in English), as well as citations found therein. Relevant articles, as well as those discovered in the peer-review process, were incorporated into this review. Phenylephrine has been studied as an antihypotensive drug in patients with severe aortic stenosis, as a treatment for decompensated tetralogy of Fallot and hypoxemia during 1-lung ventilation, as well as for the treatment of septic shock, traumatic brain injury, vasospasm status-postsubarachnoid hemorrhage, and hypotension during cesarean delivery. In specific instances (critical aortic stenosis, tetralogy of Fallot, hypotension during cesarean delivery) in which the regional effects of phenylephrine (e.g., decreased heart rate, favorable alterations in Q(p):Q(s) ratio, improved fetal oxygen supply:demand ratio) outweigh its global effects (e.g., decreased cardiac output), phenylephrine may be a rational pharmacologic choice. In pathophysiologic states in which no regional advantages are gained by using an α(1) agonist, alternative vasopressors should be sought.

These review articles reinforce my own bias against the use of pure pressors in septic shock, although clearly more clinical research is needed. I am inclined to agree with the reviewers’ concluding statement:
…in all clinical settings, phenylephrine reduces cardiac output, and in most clinical settings has been shown to significantly increase LV afterload. Thus, only in instances in which its regional effects are thought to outweigh its global effects should phenylephrine be used for the treatment of hypotension.
1. The physiologic implications of isolated alpha(1) adrenergic stimulation
Anesth Analg. 2011 Aug;113(2):284-96
2. The clinical implications of isolated alpha(1) adrenergic stimulation
Anesth Analg. 2011 Aug;113(2):297-304
3. Phenylephrine versus norepinephrine for initial hemodynamic support of patients with septic shock: a randomized, controlled trial
Crit Care. 2008;12(6):R143
Full Text available here

Acute Med, All Updates, ICU, Kids, PHARM, Resus

Pre-hospital ECMO

Leave a comment

Two cases are reported of the pre-hospital institution of venoarterial extracorporeal membrane oxygenation (ECMO) for patients in cardiac arrest. One was from France and the other from Germany – both countries with mature physician-staffed pre-hospital systems. The two cases were a 9 yr old drowning victim1 and a 48 year old marathon runner2. They each received BLS then ACLS then ECMO, and both went from asystole to sinus rhythm after the institution of ECMO. Sadly both failed to neurologically recover and died in hospital.
If irreversible anoxic encephalopathy could be detected in the field, patients could be better selected for this intervention. An editorialist3 states:


Until we have a hand held device which can measure neuronal integrity on a cellular level in the field we must use our best judgement, and in many cases give the patient the benefit of the doubt by cannulating them, cooling for 24 h and then making a neurological assessment and withdrawing ECLS if necessary.

Other issues to consider are:

  • Can society afford this level of intervention?
  • Could this intervention, when associated with brain death, result in sufficiently recovered organs for transplantation?
  • How can the infrastructure be created to enable rapid institution of pre-hospital ECMO?

I suspect as the equipment becomes even more portable and self-maintaining, pre-hospital / retrieval physicians already expert in critical care interventions such as seldinger-guided vascular access will be the ones instituting this therapy. In the meantime, we await evidence of outcome benefit and some objective means of case selection.
1. Out-of-hospital extracorporeal life support for cardiac arrest—A case report
Resuscitation. 2011 Sep;82(9):1243-5
2. Out-of-hospital extra-corporeal life support implantation during refractory cardiac arrest in a half-marathon runner
Resuscitation. 2011 Sep;82(9):1239-42
3. Community extracorporeal life support for cardiac arrest – When should it be used?
Resuscitation. 2011 Sep;82(9):1117

All Updates, Kids, Resus

Prehospital resuscitative hysterotomy

Leave a comment


My colleagues and I describe a tragic case in this month’s European Journal of Emergency Medicine1. Our physican-paramedic team was called to the home of a collapsed 38-week pregnant female who was in asystolic cardiac arrest. A peri-mortem caesarean delivery was performed by the physician in the patient’s home and the delivered newborn required intubation and chest compressions for bradycardia before resuming good colour and heart rate. Sadly there was ultimately a fatal outcome for both patients, but this case reminds us of the indications for this intervention and for emergency and pre-hospital physicians to be prepared to do it. A literature search yielded only one other reported prehospital case in recent medical literature2.

1.Prehospital resuscitative hysterotomy
Eur J Emerg Med. 2011 Aug;18(4):241-2
2.Out-of-hospital perimortem cesarean section
Prehosp Emerg Care. 1998 Jul-Sep;2(3):206-8

All Updates, Kids

CRP helpful in risk stratifying febrile kids

Leave a comment

In febrile children, peripheral white blood cell counts were not helpful in separating children with self limiting infections from those with serious bacterial infections, but serum C reactive protein was1: febrile children with serum C reactive protein concentrations of 20 mg/L or less have a 5% risk of serious infection, whereas those with serum concentrations greater than 80 mg/L have a risk of 72%; children with intermediate values have a risk of about 15%. According to the accompanying BMJ editorial2:
This grouping, although imperfect, provides some guidance to help clinicians deciding which children may avoid extensive evaluation and treatment.

OBJECTIVE: To collate all available evidence on the diagnostic value of laboratory tests for the diagnosis of serious infections in febrile children in ambulatory settings.

DESIGN: Systematic review.

DATA SOURCES: Electronic databases, reference tracking, and consultation with experts.

STUDY SELECTION: Studies were selected on six criteria: design (studies of diagnostic accuracy or deriving prediction rules), participants (otherwise healthy children and adolescents aged 1 month to 18 years), setting (first contact ambulatory care), outcome (serious infection), features assessed (in first contact care), and data reported (sufficient to construct a 2×2 table).

DATA EXTRACTION: Quality assessment was based on the quality assessment tool of diagnostic accuracy studies (QUADAS) criteria. Meta-analyses were done using the bivariate random effects method and hierarchical summary receiver operating characteristic curves for studies with multiple thresholds.

DATA SYNTHESIS: None of the 14 studies identified were of high methodological quality and all were carried out in an emergency department or paediatric assessment unit. The prevalence of serious infections ranged from 4.5% to 29.3%. Tests were carried out for C reactive protein (five studies), procalcitonin (three), erythrocyte sedimentation rate (one), interleukins (two), white blood cell count (seven), absolute neutrophil count (two), band count (three), and left shift (one). The tests providing most diagnostic value were C reactive protein and procalcitonin. Bivariate random effects meta-analysis (five studies, 1379 children) for C reactive protein yielded a pooled positive likelihood ratio of 3.15 (95% confidence interval 2.67 to 3.71) and a pooled negative likelihood ratio of 0.33 (0.22 to 0.49). To rule in serious infection, cut-off levels of 2 ng/mL for procalcitonin (two studies, positive likelihood ratio 13.7, 7.4 to 25.3 and 3.6, 1.4 to 8.9) and 80 mg/L for C reactive protein (one study, positive likelihood ratio 8.4, 5.1 to 14.1) are recommended; lower cut-off values of 0.5 ng/mL for procalcitonin or 20 mg/L for C reactive protein are necessary to rule out serious infection. White blood cell indicators are less valuable than inflammatory markers for ruling in serious infection (positive likelihood ratio 0.87-2.43), and have no value for ruling out serious infection (negative likelihood ratio 0.61-1.14). The best performing clinical decision rule (recently validated in an independent dataset) combines testing for C reactive protein, procalcitonin, and urinalysis and has a positive likelihood ratio of 4.92 (3.26 to 7.43) and a negative likelihood ratio of 0.07 (0.02 to 0.27).

CONCLUSION: Measuring inflammatory markers in an emergency department setting can be diagnostically useful, but clinicians should apply different cut-off values depending on whether they are trying to rule in or rule out serious infection. Measuring white blood cell count is less useful for ruling in serious infection and not useful for ruling out serious infection. More rigorous studies are needed, including studies in primary care, to assess the value of laboratory tests alongside clinical diagnostic measurements, including vital signs.

1. Diagnostic value of laboratory tests in identifying serious infections in febrile children: systematic review
BMJ. 2011 Jun 8;342:d3082
2. How useful are laboratory tests in diagnosing serious infections in febrile children?
BMJ. 2011 Jun 8;342:d2782

All Updates, Kids, PHARM, Resus

Normal heart and respiratory rates in children

Leave a comment


A large review has established normal ranges of heart rate and respiratory rate in children from birth to 18 years of age. Some of the results differed markedly from some existing ranges quoted, such as in the Advanced Paediatric Life Support Course.

BACKGROUND: Although heart rate and respiratory rate in children are measured routinely in acute settings, current reference ranges are not based on evidence. We aimed to derive new centile charts for these vital signs and to compare these centiles with existing international ranges.

METHODS: We searched Medline, Embase, CINAHL, and reference lists for studies that reported heart rate or respiratory rate of healthy children between birth and 18 years of age. We used non-parametric kernel regression to create centile charts for heart rate and respiratory rate in relation to age. We compared existing reference ranges with those derived from our centile charts.

FINDINGS: We identified 69 studies with heart rate data for 143,346 children and respiratory rate data for 3881 children. Our centile charts show decline in respiratory rate from birth to early adolescence, with the steepest fall apparent in infants under 2 years of age; decreasing from a median of 44 breaths per min at birth to 26 breaths per min at 2 years. Heart rate shows a small peak at age 1 month. Median heart rate increases from 127 beats per min at birth to a maximum of 145 beats per min at about 1 month, before decreasing to 113 beats per min by 2 years of age. Comparison of our centile charts with existing published reference ranges for heart rate and respiratory rate show striking disagreement, with limits from published ranges frequently exceeding the 99th and 1st centiles, or crossing the median.

INTERPRETATION: Our evidence-based centile charts for children from birth to 18 years should help clinicians to update clinical and resuscitation guidelines.

Normal ranges of heart rate and respiratory rate in children from birth to 18 years of age: a systematic review of observational studies
Lancet. 2011 Mar 19;377(9770):1011-8

Acute Med, All Updates, Guidelines, ICU, Kids, Resus, Trauma, Ultrasound

Central lines in coagulopathic patients

Leave a comment

If a patient needs a central line, he/she needs one. Often low platelets or a deranged coagulation profile are cited as reasons for omitting or delaying the procedure, but this is not based on evidence of increased complications. A recent Best Evidence Topic Review concludes:

“…insertion of CVC lines do not require correction of haemostatic abnormalities prior to intervention. Rates of haemorrhage are low in patients with elevated PT, APTT or low thrombocyte count and appear to be closely related to the level of experience of the physician … rather than the defects of haemostasis. “

Links to the abstracts of a couple of relevant articles reviewed are included below.
Central line insertion in deranged clotting
Emerg Med J. 2011 Jun;28(6):536-7 Full text
Low levels of prothrombin time (INR) and platelets do not increase the risk of significant bleeding when placing central venous catheters.
Med Klin (Munich). 2009 May 15;104(5):331-5
US-guided placement of central vein catheters in patients with disorders of hemostasis
Eur J Radiol. 2008 Feb;65(2):253-6

All Updates, Guidelines, ICU, Kids, Resus, Trauma

UK Radiology guidelines for trauma

1 Comment


The Royal College of Radiologists in the UK has published a guideline document to set standards related to diagnostic and interventional radiology for use by major trauma centres (MTCs) and trauma units (TUs). The standards are:

  1. The trauma team leader is in overall charge in acute care
  2. Protocol-driven imaging and intervention must be available and delivered by experienced staff. Acute care for SIPs must be consultant delivered
  3. MDCT should be adjacent to, or in, the emergency room
  4. Digital radiography must be available in the emergency room
  5. If there is an early decision to request MDCT, FAST and DR should not cause any delay
  6. MRI must be available with safe access for the SIP
  7. A CT request in the trauma setting should comply with the Ionising Radiation (Medical Exposure) Regulations 2000 (IR(ME)R) justification regulations like any other request for imaging involving ionising radiation
  8. There should be clear written protocols for MDCT preparation and transfer to the scan room
  9. Whole-body contrast-enhanced MDCT is the default imaging procedure of choice in the SIP. Imaging protocols should be clearly defined and uniform across a regional trauma network
  10. Future planning and design of emergency rooms should concentrate on increasing the numbers of SIPs stable enough for MDCT and intervention
  11. The primary survey report should be issued immediately to the trauma team leader
  12. On-call consultant radiologists should provide the final report on the SIP within one hour of MDCT image acquisition
  13. On-call consultant radiologists must have teleradiology facilities at home that allow accurate reports to be issued within one hour of MDCT image acquisition
  14. IR facilities should be co-located to the emergency department
  15. Angiographic facilities and endovascular theatres in MTCs should be safe environments for SIPs and should be of theatre standard
  16. Agreed written transfer protocols between the emergency department and imaging/interventional facilities internally or externally must be available
  17. IR trauma teams should be in place within 60 minutes of the patient’s admission or 30 minutes of referral
  18. Any deficiency in consumable equipment should be reported at the debriefing and be the subject of an incident report

Some interesting snippets include:
IV access
Right antecubital access is preferred for contrast administration (left-sided injections compromise interpretation of mediastinal vasculature). However, if arm vein access is not possible and a central line is in situ, it should be of a type that can accept 4 ml contrast/ second via a power injector. This might require local negotiation with emergency department doctors beforehand

Pelvic fracture
If a pelvic fracture is suspected, a temporary pelvic stabilisation (wrap, binder and so on) should be applied before MDCT.
Limb fractures
Rapid immobilisation such as air splints. Only immediately limb conserving manipulations/splinting should be performed prior to CT.
Urinary catheter
All significantly injured patients without obvious contraindications should be catheterised unless this would delay transfer to CT. The catheter should be clamped prior to MDCT.
Standards of practice and guidance for trauma radiology in severely injured patients
Royal College of Radiologists – Full Text Link

Acute Med, All Updates, ICU, Kids, Resus

Hyperkalaemia dogmalysis

Leave a comment


One of the things I enjoy most is the dismantling of medical dogma. In his brilliant blog Precious Bodily Fluids, nephrologist Joel Topf reviewed some of the hyperkalaemia literature and offers some of the following pearls:

  • The ECG is insensitive and non-specific as a means of diagnosing (and in particular ruling out) hyperkalaemia (sensitivity of ‘strict’ criteria of symmetrical peaked T waves that resolve on follow up: 18%; sensitivity of any ECG change: 52%).
  • The dangers of calcium treatment for digoxin toxicity-associated hyperkalaemia may be exaggerated and are supported by very weak evidence
  • Sodium bicarbonate does not effectively lower potassium but does lower ionised calcium which can increase the risk of hyperkalaemia-associated dysrhythmia

Read the full blog post here
View Dr Topf’s presentation below:

All Updates, ICU, Kids, Resus

Steroids for sepsis in kids

Leave a comment

A small retrospective study suggests adrenal insufficiency is common in kids with septic shock, and that steroid administration in these children was associated with a decrease in vasoactive drug requirements.

INTRODUCTION: Adrenal insufficiency may be common in adults and children with vasopressor-resistant shock. We developed a protocolized approach to low-dose adrenocorticotropin testing and empirical low-dose glucocorticoid/mineralocorticoid supplementation in children with systemic inflammatory response syndrome and persistent hypotension following fluid resuscitation and vasopressor infusion.
HYPOTHESIS: We hypothesized that absolute and relative adrenal insufficiency was common in children with systemic inflammatory response syndrome requiring vasopressor support and that steroid administration would be associated with decreased vasopressor need.
METHODS: Retrospective review of pediatric patients with systemic inflammatory response syndrome and vasopressor-dependent shock receiving protocol-based adrenocorticotropin testing and low-dose steroid supplementation. The incidence of absolute and relative adrenal insufficiency was determined using several definitions. Vasopressor dose requirements were evaluated before, and following, initiation of corticosteroids.
RESULTS: Seventy-eight patients met inclusion criteria for systemic inflammatory response syndrome and shock; 40 had septic shock. Median age was 84 months (range, 0.5-295). By adrenocorticotropin testing, 44 (56%) had absolute adrenal insufficiency, 39 (50%) had relative adrenal insufficiency, and 69 (88%) had either form of adrenal insufficiency. Adrenal insufficiency incidence was significantly higher in children >2 yrs (p = .0209). Therapeutic interventions included median 80-mL/kg fluid resuscitation; 65% of patients required dopamine, 58% norepinephrine, and 49% dopamine plus norepinephrine. With steroid supplementation, median dopamine dose decreased from 10 to 4 μg/kg/min at 4 hrs (p = .0001), and median dose of norepinephrine decreased from 0.175 μg/kg/min to 0.05 μg/kg/min at 4 hrs (p = .039).
CONCLUSIONS: Absolute and relative adrenal insufficiency was prevalent in this cohort of children with systemic inflammatory response syndrome and vasopressor-dependent shock and increased with age. Introduction of steroids produced a significant reduction in vasopressor duration and dosage. Use of low-dose adrenocorticotropin testing may help further delineate populations who require steroid supplementation.

Incidence of adrenal insufficiency and impact of corticosteroid supplementation in critically ill children with systemic inflammatory syndrome and vasopressor-dependent shock
Crit Care Med. 2011 May;39(5):1145-50