Heat Stress

With Sydney temperatures consistently reaching the high 30’s and early 40’s recently it is perhaps timely to revise heat related illness. It is also worth considering the steps we can take to keep ourselves cool in the same environmental conditions.

Heat related illness covers a spectrum which, at the most extreme end, includes heat stroke. This is defined as hyperthermia >40 degrees, associated with neurological dysfunction. The neurological dysfunction can manifest in many ways including ataxia, delirium, seizures and coma. The patient may also be tachycardic and hypotensive (echo may show either a hypodynamic or hyperdynamic LV). Sweating may be absent. Unrecognised heat stroke carries a mortality of up to 30%.

Management

Aggressive cooling in the field can prevent a cascade of organ dysfunction and significantly improve prognosis. Initial management and cooling methods will be dictated by resources and environment but consider:

  • Moving the patient into the shade
  • Using pack equipment to create some shade e.g. the warming blanket could be used as a canopy if bystanders are able to hold it aloft.
  • Remove the patients clothing
  • Place wet towels or sheets over the patient (road crew may have some)
  • Place ice packs in axillae, groin, neck
  • Try to create some airflow over the patient if possible (not always practicable in the prehospital environment)
  • Stop cooling at approximately 38-38.5 degrees core temp to avoid overshoot hypothermia.
  • Paracetomol is ineffective

Don’t forget standard resuscitation measures:

A = RSI if patient is obtunded and unable to protect airway

B = Ventilate as required. Be aware that pulmonary oedema and ARDS may accompany heat stroke if you are having difficulty ventilating

C = iv fluids may be needed but don’t equate hyperthermia with hypovolaemia. Depending on clinical circumstances, the patient may be either mildly or profoundly volume depleted. Be aware of dilutional hyponatraemia in endurance athletes consuming lots of sports drinks. This can be an important differential for altered LOC and seizures.

Inotropes may be required if shock is refractory to fluid resuscitation but be aware that adrenaline and noradrenaline will cause vasoconstriction that may impair cooling.

D = Benzodiazepines for seizures, don’t forget to check a BSL

Self Care

Self-care is important on these missions as crew members are being exposed to the same environmental conditions as the patient and may have had to exert themselves to get there (winch, bush walk etc.) Make sure you are well hydrated pre mission and carry additional water. Urine colour is the best guide to your hydration status. Ice packs are available in the ready room and can be used by crew if needed. Consider your uniform sunhat if your head is exposed. Sun cream is also available in the ready room. If you are feeling unwell due to heat, communicate this immediately to your crew.

Heat stress

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Double Pumping Vasoactive Drugs

A significant number of our critical care patients are dependent on vasoactive drugs, so it is worth reviewing the process for managing these infusions during inter-hospital transfers.

pastedgraphic-2

The priming volume of the distal lumen of a central line is 0.44mls. Therefore an infusion running at 10mls / hour could take approximately 3 minutes to reach the patient if started de novo. The half-life of inotropes such as adrenaline and noradrenaline is short, approximately 1 minute. This leaves the patient vulnerable to a period of hypotension. Corrective bolusing of vasoactive drugs is not recommended as it can lead to large, and potentially detrimental, swings in blood pressure. Therefore a smooth transition between syringe pumps is recommended to maintain haemodynamic stability.

There are a number of different methods for double pumping but one suggested protocol is as follows:

  1. Leave infusion number 1 running at its current rate (100%)
  2. Commence infusion number 2 at 50% of the rate of infusion number 1
  3. Wait for a small kick in blood pressure to indicate that the second infusion is reaching the patient. This can be up to but should not exceed SBP 20mmHg
  4. Immediately increase infusion number 2 to 100% (the current rate of infusion 1) and reduce infusion number 1 back to 50%.
  5. Reduce infusion 1 back to zero incrementally over a few minutes ensuring that BP doesn’t drop.

Tips and tricks

  1. Avoid the use of a 3-way tap if you have enough ports to manage without. Three-way taps increase the complexity of the process and the likelihood of an error. No matter how intelligent you think you are, 3-way taps have a habit of embarrassing you. If you really must use a 3-way tap make sure both taps are “on” to the patient during the process and then make sure the correct tap is left “on” at the end.
  2. Dedicate a member of the HEMS team to the double pumping process and avoid being interrupted during it.
  3. Use a dedicated line for vasoactive drugs to prevent inadvertent bolusing
  4. Label the line and the syringe driver clearly to prevent confusing the vasoactive drug with sedation (which can be, and often is, bolused)
  5. If you are about to embark on a long transfer you may want to replace a single strength vasoactive drug with double strength. Take this into account when double pumping. If infusion 2 is double strength it will need to be started at 25% of infusion 1 and then increased to 50% once the BP kick is seen.
  6. Be patient. Depending on the infusion rate and the dead space in the catheter lumen, the process can take several minutes. It is worth taking the time to do it smoothly rather than trying to speed it up by increasing infusion rates or bolusing.

Further reading:

Practical considerations in the administration of i ntravenous vasoactive drugs in the critical care set ting the double pumping or piggyback technique–part oneIntensive and Critical C

An in vitro evaluation of infusion methods using a syringe pump to improve noradrenaline administrationActa Anaesthesiologica Scandinavica 2014 GENAY

Practical considerations in the administration of intravenous vasoactive drugs in the critical care settingIntensive and Critical Care Nursing 2004 Morrice

Management of the changeover of inotrope infusions in childrenIntensive and Critical Care Nursing 2004 ArinoChangeovers of vasoactive drug infusion pumps impact of a quality improvement programCritical Care 2007 Argaud

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Clinical Governance & Education Day – 7th March

Slide1

Here is a link to the paper that will be discussed at Journal Club

Crewdson et al(1)

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Blue Sky Trauma from Umbara Base Hospital Part Two

The following learning points are collated from Regional and Rural hospitals of NSW, Australia, represented here by a single fictional institution – Umbara Base Hospital.  Cases are amalgamated and anonymised (including alteration of patient demographics) such that similarity to real patients is coincidental. 

Below are some high-yield learning points collated from the Umbara Hospital trauma case review meeting.

Beware distracting injury

Patients with blunt trauma with significant orthopaedic injury may have other significant other injuries that are difficult to assess on history and examination and easy to miss.

Here’s a good article on this.

Anchoring bias may also occur, particularly in inter-hospital transfers. These are higher risk patients for missed/delayed diagnosis. Reassess the patient from the start.

Rib injuries in the elderly

Elderly patients (>65) who sustain blunt chest trauma with rib fractures have twice the mortality and thoracic morbidity of younger patients with similar injuries. For each additional rib fracture in the elderly, mortality increases by 19% and the risk of pneumonia by 27%.

CXR is inaccurate in diagnosing the presence and number of rib fractures – hence we should have a low threshold for CT to further assess. Current best practice is the ChIP protocol.

Angioembolisation

Angioembolisation in renal trauma is effective in selected patients.

Trauma CT: Blue arrow is contrast ‘blush’=active bleeding point. Red arrow is perinephric haematoma.

Angioembolisation. Red arrow=coils in arcuate artery of kidney which has stopped the bleeding.

When transferring these patients from smaller hospitals to larger centres, consider whether initial destination should be the ED for rapid re-assessment prior to entering IR suite.

Stab Heart

Anterior and posterior ‘cardiac box’

Penetrating trauma to the ‘cardiac box’ may result in cardiac injury and pericardial effusion leading to tamponade. A permissive hypotension strategy is followed where practical.

Diagnosis may be made by eFAST, bedside formal echo or by CT depending on clinical stability.

Axial CT showing anterior pericardial effusion (blood) from trauma (blue arrow)

Pericardial fat stranding caused by pericardial blood (red arrow)

The key operative finding at the tertiary trauma centre was right ventricle laceration, which was successfully repaired.

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Clinical Governance Day, 24th January 2018

Slide1Guidelines for the management of tracheal intubation in critically ill adults

 

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Education Day – Wednesday 10th January

Education Day 10th Jan

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Blue Sky Trauma from Umbara Base Hospital

The following learning points are collated from Regional and Rural hospitals of NSW, Australia, represented here by a single fictional institution – Umbara Base Hospital.  Cases are amalgamated and anonymised (including alteration of patient demographics) such that similarity to real patients is coincidental. 

Below are some high-yield learning points collated from the Umbara Hospital trauma case review meeting.

Chest drains

Always check the chest drain with a CXR – particularly check for the drain’s position and for complications such as kinking, as can be seen in this left sided CXR.

Pneumothorax is often associated with subcutaneous emphysema (free air in the tissues under the skin). It feels like bubble-wrap and looks like this on CT. Don’t press too hard though – it’s likely there are rib fractures underlying the air and they are extremely painful!

Elderly trauma

Trauma in older patients is increasing with our ageing population here in Umbara – ever improving management of chronic health conditions means people are living longer. It is difficult to predict mortality in elderly trauma and hence some scoring systems exist.

Geriatric Trauma Outcome: Age + (2.5x ISS) + 22 (if PRBCs administered)

Mortality: 205=75%, 233=90%, %, 252= 95%, 310=99%.

These scoring systems may help guide discussions with patients and their families in the future.

Non-accidental Injury in Children

Data from the UK Trauma Audit and Research Network (TARN) showed that 2.5% of children in their database had suspected child abuse underlying their injuries. 97.7% of these children were aged <5yrs; 76.3% were aged <1yr. Injury severity score (ISS) was also greater in patients with suspected child abuse: they were 1.7x as likely to have an ISS score >15.

You can read more in this free-to-access paper.

What can we do?

IDENTIFY risk factors through history, examination, observation.

LISTEN and watch parent-child interaction

CONSIDER the possibility

DON’T DISMISS non-accidental injury as a possibility due to lack of physical findings

DOCUMENT carefully, clearly and contemporaneously

PREVENT  by linking with services

KNOW your legal requirements for reporting

Risk Factors for NAI

Although non-accidental injury can occur in the absence of these factors, there are several factors which have associations with non-accidental injury.

In the child:

  • Chronic illness, disability or developmental problem
  • Prematurity
  •  Age of child
  • “Difficult” behaviour

Parent/Family:

  • Unwanted pregnancy
  • Young parents
  • Single parent family
  • Relationship problems
  • Exposure to drug and alcohol abuse and/or family violence
  • Low socioeconomic status
  • Social isolation
  • Physical or mental illness in a parent

Other concerning features:

  • Poor hygiene
  • Dirty clothes
  • Missing a lot of school
  • Previous contact with FACS / CPU

Clinical/Attendance features:

  • Delay in presentation
  • Injury not explained by story
  • Inconsistent with developmental ability (know developmental milestones! Here’s a quick reminder)
  • Inconsistencies in history and changes over time
  • Unexplained or unwitnessed fall with neglect
  • Previous suspicious injuries
  • Unusual parent – child interaction
  • Failure To Thrive (FTT)
  • Resuscitation efforts caused injuries
  • Patterned bruise/burns; certain distribution
  • Spiral/transverse long bone fractures, particularly in non-mobile children

Child Protection Courses: http://www.heti.nsw.gov.au/Courses/Child-Protection/

Non-accidental injury blog & podcast: http://stemlynsblog.org/child-protection/

From the Horse’s Mouth

When Umbara Base Hospital’s own Dr Tallie fell from her horse earlier this month and ended up being treated in her own Emergency Department, she was in a unique position in being able to provide constructive feedback around her own care with a full understanding of the processes of the hospital.

This month we invited her to share her thoughts at the trauma case review meeting and were delighted to learn the following.

  • Prehospital methoxyflurane is an excellent analgesic and she was very grateful for it
  • She found the experience had increased her trust: she was happy to put her life in hands of the staff of Umbara Base Hospital and has a renewed appreciation for them all as a result
  • She particularly noted that nurses are awesome (both during her ED and ICU stays): she added,  “it’s the ‘little things’ that make all the difference”.
  • Having experienced both, she found regional block much better in the pain management of her rib fractures than drugs.
  • Overall she was dismayed to realise just how long bones take to heal.

Huge thanks to Dr Tallie for her insights – we wish her well on her recovery.

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