There has been an exponential rise in COVID-19 cases. There is no doubt we’re feeling the effects of that all over the world. Many people, especially it seems, the lay public and politicians, have a hard time understanding the meaning of ‘exponential’.



The scariness of exponential growth shown here with E.coli
Image by Stewart EJ, Madden R, Paul G, Taddei F (2005) / CC BY-SA



But can exponential rise continue? If cases double every 3-4 days, then based on today’s figures from the Johns Hopkins Dashboard (1st April) by May 6 there will over 8.7 billion people infected, which is more than everyone on the planet, and clearly impossible.



This means the rise must tail off eventually. In fact, the more people there are who are infected, the harder it is to find someone to infect with the virus who hasn’t already got it. Also, spread should be limited by the social distancing and other measures (such as handwashing).



This actually gives rise to a LOGISTIC curve, rather than an EXPONENTIAL curve. This is an S-shaped curve that describes population growth (in both viruses and people) as well as other phenomena in economics and science(1).



Attribution: Qef / Public domain



Notice in the above curve the mid-point marked 0.5. This is the inflection point when the rate of increase in cases stabilises before declining. Specifically, the ‘Growth Factor’, or number of new cases in one day divided by the number of new cases the previous day, equals 1. Note at this point cases are still increasing – the virus is still spreading – but it’s not accelerating, and therefore no longer on an exponential trajectory.



Image from ‘Exponential growth and epidemics’ by 3Blue1Brown



This isn’t the only model to describe pandemics and none is perfect(2). We still can’t predict what will happen with SARS-CoV-2 and we absolutely need to continue to enforce strict containment measures. But having a basic understanding of the data gives us ways to visualise it that allow comparisons, and show which countries have ‘fallen off’ the exponential rise curve.



Logarithmic graph by Aatish Bhatia in collaboration with Minute Physics – see https://aatishb.com/covidtrends for up-to-date animated graph



Since in most places, we are still on the exponential part of the curve, it is imperative to educate as many people as we can on the benefits of strict isolation and hygiene measures:



Great infographic by @GaryWarshaw and @SignerLab




The best brief explanation of the above, which prompted me to write this brief post, is by the brilliant minutephysics



Take a few minutes to watch the video below:







Please note all the caveats at the end of the video. And one final one – I’m not an epidemiologist or mathematician. I’ve just been wrestling with what the endpoint of exponential rise would be and found these resources helpful.



References



1. https://www.nctm.org/Classroom-Resources/Illuminations/Interactives/Pandemics-How-Are-Viruses-Spread/



2. Yang W, Zhang D, Peng L, Zhuge C, arXiv LHAP, 2020. Rational evaluation of various epidemic models based on the COVID-19 data of China. arxivorg
…

One of my nursing colleagues was telling a story the other day about one of the first resuscitations we did together in the ED several years ago. It demonstrates the principle of establishing control of a sub-optimally coordinated team by using some form of attention grabber. She kindly agreed to write down her recollection for me to share here:
I have finally found 2 minutes to sit down and write you the story I was telling you about the other week….
We were in the middle of a resus in the ED, it was chaotic, loud and messy.
I remember you calling out in a commanding voice for everyone to stop (can’t recall what you actually said) but when we all looked up and fell silent you lifted up one leg, let a rather loud large fart out and then very calmly proceeded to take control of the situation. Everyone was so stunned, and slightly amused that the whole situation just settled right down and we all cracked on with the resus in a much more organised fashion.
I don’t know if you know I own a first aid training company. I tell this story when I am teaching. I explain to people that an emergency situation can be chaotic and stressful and someone has to take control. Sometimes you need to take a second to get a grip of yourself and others before you can be of any help to the person in need.
By telling your story it makes people realise you can stop for a second to gather yourself, take stock of what is needed then crack on. Sometimes it takes extreme measures such as dropping a fart to get people to get back on track.
You have given me many stories over the years but the fart one has got the most traction so far.
See you at work
 
 


I accept that some people may find this offensive or consider it inappropriate or unprofessional. Please consider:



All mammals produce flatus.Holding on to flatus can be uncomfortable and can distract a resuscitation team leader, potentially adversely affecting outcome.The performance had its desired effect, helping the resuscitation.The patient was intubated and therefore not at olfactory riskC’mon jeez it was just a fart
…

This video shows the mechanism for dislodgement and deformation of humeral intraosseous needles and how to avoid this.
In summary, if you need to abduct the arm (eg. for thoracostomy), keep the thumbs down (ie. have the arm internally rotated at the shoulder). Otherwise the IO catheter may bend or fall out.

References:
1. Pasley J, Miller CHT, DuBose JJ, Shackelford SA, Fang R, Boswell K, et al. Intraosseous infusion rates under high pressure. Journal of Trauma and Acute Care Surgery. 2015 Feb;78(2):295–9.
2. Paxton JH, Knuth TE, Klausner HA. Proximal Humerus Intraosseous Infusion: A Preferred Emergency Venous Access. The Journal of Trauma: Injury, Infection, and Critical Care. 2009 Sep;67(3):606–11.
3. Cho Y, You Y, Park JS, Min JH, Yoo I, Jeong W, et al. Comparison of right and left ventricular enhancement times using a microbubble contrast agent between proximal humeral intraosseous access and brachial intravenous access during cardiopulmonary resuscitation in adults. Resuscitation. 2018 Aug;129:90–3.
4. Knuth TE, Paxton JH, Myers D. Intraosseous Injection of Iodinated Computed Tomography Contrast Agent in an Adult Blunt Trauma Patient. Ann Emerg Med. 2011 Apr;57(4):382–6.
5. Mitra B, Fitzgerald MC, Olaussen A, Thaveenthiran P, Bade-Boon J, Martin K, et al. Cruciform position for trauma resuscitation. Emerg Med Australas. 2017 Apr;29(2):252–3.
6. Reid C, Healy G, Burns B, Habig K. Potential complication of the cruciform trauma  position. Emergency Medicine Australasia. 2017 Apr 27;29:252.
7. Reid C, Fogg T, Healy G. Deformation of a humeral intraosseous catheter due to positioning for thoracostomy. Clin Exp Emerg Med. 2018 Sep;5(3):208–9.
…

Towards Excellence in Resuscitation
Analysing Difficult Resuscitation Cases #2
Occasionally we step out of the resuscitation room feeling like a case should have gone better, but it can be hard to put our finger on just where it went wrong. In my last post I discussed the STEPS approach to analysing resuscitation cases: Self, Team, Environment, Patient and System.
Occasionally you can get a case where the STEPS seem to be aligned but things still feel bad. In which the outcome was unsatisfactory because the plan was wrong, or the team wasn’t able to execute the plan. Consider the following case.
1. A patient with a past history of DVT no longer on anticoagulants presents with chest pain and syncope.
She is severely hypotensive with a raised jugular venous pressure and a clear chest x-ray. A working diagnosis of pulmomary embolism is made.
Discussions ensue regarding empirical fibrinolysis and a respiratory physician is consulted, who over the phone cautions against treating without a CT pulmonary angiogram.
The patient is given heparin and transferred to the CT scanner where she arrests. Intravenous rtPA is given during CPR but no return of spontaneous circulation is achieved and she is pronounced dead after 30 minutes of resuscitation.
 
On this occasion the team worked efficiently and communicated well under clear leadership. Everyone knew the plan and shared the mental model. The environment was well controlled and the patient had been swiftly moved to CT within 20 minutes of arrival. Thanks to simulation training the well rehearsed cardiac arrest resuscitation was conducted with precision and the team was able to rapidly access the thrombolytic and knew the correct dose.
By a quick STEPS analysis, this case appears to have gone as well as could be expected. Perhaps there is nothing to learn. Some you win, some you lose, no?
No. Autopsy revealed type A aortic dissection with pericardial tamponade.
The management may have been efficient but it failed to be effective. In other words, things were done right, but the right things weren’t done; they did the wrong things right.
This might be an example where STEPS is inadequate, and instead we should evaluate the clinical trajectory. The cognitive bias that led to a lack of consideration of alternative diagnoses might be classifiable under ‘self’ or ‘team’ but I find it more helpful to consider it under a failure of strategy. What is strategy? Strategy in my mind is another word for plan. The plan is based on a particular resuscitation goal, and will consist of the procedures & skills required to action the plan. We can thus break down an attempted clinical trajectory into:
Goal (what are we trying to achieve)
Strategy, or Plan (what’s our plan to get there?)
Tactics, or Actions (what procedures will be required to execute the plan)
And, at more granular level: If we’re failing at the procedural level, the components of procedures, namely Skills & Microskills.
So, as we zoom in from macro to micro in setting the clinical trajectory, we can look at Goals, Plan, Actions, and Skills:

In the above case it appears the following was applied, in terms of Goal-Plan-Actions-Skills:
G – resuscitate hypotensive patient
P – give fibrinolysis for likely PE
A – consult respiratory physician, get CTPA
S – request scan, give heparin, transport to CT
The goal was appropriate, but the plan was ineffective.
The following approach would have been more effective.
G – resuscitate hypotensive patient
P – identify cause of undifferentiated hypotension and initiate treatment in the resus room 
A – thorough bedside assessment in patient too sick to move: history, physical, CXR, ECG, labs, POCUS
S – Basic cardiac ultrasound
By planning to identify and treat the cause of hypotension in the resus room, the more appropriate investigation would have been selected (cardiac ultrasound) and the correct diagnosis is much more likely to have been made.
Let’s look at some other cases:
2. An 88-year-old male presents by ambulance to the ED with dizziness. He is hypotensive, pyrexial, hypoxic and confused.
His chest x-ray shows likely bronchopneumonia. He has appropriate initial resuscitation and ICU is consulted. Soon he is intubated and on high dose vasoactive medication with escalating doses despite ongoing hypotension, anuria, and a lactate of 11 mmol/l, increased from 8 on arrival.
As he is being wheeled off down the corridor towards ICU his distraught and frail wife arrives. She is taken to the quiet room where she explains that her husband would never want to be ‘on a life support machine’ and asks ‘can’t you just keep him comfortable’?
 
G – the goal – to provide maximally aggressive resuscitation – was not in keeping with the patient’s wishes. If the goal had been to provide care in accordance with his wishes, the plan could have included attempts to ascertain these sooner while providing initial treatment. Upon gaining sufficient information, a new goal can be established: maximising the patient’s comfort and dignity.
3. An obese 30-year-old female presents with syncope. At triage she is pale, tachycardic & hypotensive. Clinical and sonographic assessment, including free intraperitoneal fluid and a positive urine HCG, is suggestive of ruptured ectopic pregnancy.
The gynaecologist and anaesthetist ask the ED team to bring the patient straight to the operating room. The ED team spends 20 minutes struggling to obtain intravenous access, eventually placing a 22G intravenous catheter in the patient’s hand and a humeral intraosseous needle.
Her shock is considerably worse on arrival in theatre, despite attempts to transfuse O negative blood en route.
 
Goal – get her safely to the operating room
Plan – vascular access, cross match blood, start haemostatic resuscitation, go to OR as soon as possible
Actions – peripheral and/or intraosseous cannulation attempts
Skills – vascular access skills
Here the failure was at the actions and skills level. Better vascular access could have been attained using ultrasound guided peripheral cannulation, or central vascular access, or earlier intraosseous insertion.
4. A 120kg 32-year-old male with a history of deliberate self harm presents on the night shift with coma due to mixed benzodiazepine and venlafaxine overdose.
The decision is made to intubate for airway protection. After rapid sequence induction direct laryngoscopy is attempted by the emergency registrar who obtains a grade 4 view. Cricoid pressure is removed resulting in a grade 3 view.
The registrar asks for a bougie which she passes and then railroads the tracheal tube over it. The cuff is inflated, capnography is connected, and the self-inflating bag is connected and squeezed while the chest is auscultated.
The abdomen distends, the capnograph remains flat, and gastric contents are seen to pass upward through the tube into the self-inflating bag. The tube is immediately removed and bag-mask ventilation is attempted. The oxygen saturation is now 78% and the airway is soiled. The airway is suctioned and repeat attempts to bag-mask ventilate fail. A successful cricothyroidotomy is performed and the patient subsequent has full neurological recovery.
 
Goal – Provide supportive care and minimise complications from overdose
Plan – Airway protection and admit to ICU for monitoring
Actions – Rapid sequence intubation, ICU referral
Skills – Pre-, peri- and post-intubation oxygenation techniques; patient positioning; rapid sequence induction of anaesthesia; direct laryngoscopy; bougie handling techniques; external laryngeal manipulation
In this case the patient was not placed in the ramped position and no nasal cannulae were applied for apnoeic oxygenation. A tube was railroaded over an oesophageal bougie, which arguably should not occur if ‘hold up’ is sought when the bougie is placed.
Although the goal, plan and actions were appropriate, the team did not demonstrate adequate skill in this procedure. Likely due to a failure of training, standardised procedures, and checklists (or their application), this could also be identified as a ‘system’ problem in STEPS. It is also possible that the intubator forgot her training under stress – a problem classifiable under ‘self’. Alternatively other members of the team may have had knowledge but didn’t speak up or cross-check their colleague, which would be a ‘team’ issue.
Limitations of this approach
This sort of analysis is retrospective and subjective and at risk of hindsight bias (e.g. distortion due to projection, denial, or selective recall). However, these limitations do not negate the value of the learning exercise, particularly if we are aware of them and strive to minimise their impact (e.g. write down the details of a cases as soon as possible afterward). It at least provides a structure for individuals and teams to begin the conversation about where and how things may have been suboptimal.
Goals may be multiple and may change according to incoming information, and for each goal there may be several viable alternative plans. STEPS and GPAS may overlap, eg. team failures may result in inappropriate goals and strategies, or in failed procedures.
Summary
These models may prove helpful as a means of dissecting a case in a structured way. Put simply, STEPS offers a structure for identifying efficiency improvements (“doing things right”) and GPAS  can help us assess effectiveness (“doing the right things”).
Another way of looking at it is that STEPS provides the components of a resus at any point in time, and GPAS defines the trajectory: where the resus is going and how to get there.
I use this structure to analyse cases in my own clinical practice and in my teaching. I would be interested to hear from others’ experience. Do you find this approach useful in identifying areas for improvement in those cases that you feel should have gone better?
Thanks to Chris Nickson for his comments and improvements to this post…

Towards Excellence in Resuscitation
Analysing Difficult Resuscitation Cases #1
A resuscitationist agonises. These words, expressed by Scott Weingart during a podcast we did together, ring true to all of us who strive to improve our practice. Driven by the passionate conviction that we should never lose a salvageable patient through imperfect care, we relive cases and re-run them through our mental simulators to identify areas for improvement.
In the search for actionable items though, we occasionally exit this process empty-handed. Something about a case felt wrong although ostensibly all the clinical interventions may have been appropriate. It is in these cases that it can be helpful to have a structure to aid analysis.
I, along with an international, interdisciplinary faculty of resuscitationists, have previously proposed an easily remembered system for optimising the clinical and non-technical components of resuscitation immediately before and during a patient encounter, dubbed the ‘Zero Point Survey’ (ZPS)(1), so called because first contact with a patient is rarely ‘Time Zero’ for a prehospital mission or hospital resuscitation case; there is invariably time for preparation of oneself, one’s team, and the environment (including equipment) prior to the primary survey and commencement of resuscitation. Following the assessment and management of STEP (self, team, environment & patient), the team should be regularly Updated on patient status and informed of the Priorities.
But ‘self, team, environment and patient’ isn’t just a useful system for case preparation. It can also be used for case analysis. I have found by discussing many ‘unsatisfactory’ cases over the years with participants in human factors workshops that STEP can help us identify where the issues lie. Accompanying all these factors is another ’S’: the system in which they interplay – the organisational rules, processes, policies, resources and deficiencies that may facilitate or obstruct an effective resuscitation(2).






Using STEPS to analyse cases
The following (genuinely) hypothetical resus cases demonstrate how the application of this framework – Self, Team, Environment, Patient, System – might help identify correctible factors for future resuscitations:



1. Cardiac arrest in the bathroom on the orthopaedic ward – “it was chaos, there were too many people, and the resus trolley wasn’t properly stocked”.



STEPS analysis:
Team – Leader needed to assign roles and allocate tasks
Environment – Crowd control needed, lack of equipment
System – Adequate checks for resus trolley not in place



2. 19-year-old male stabbed in the chest and arrested on arrival in hospital. CPR provided but went from PEA to asystole. Team leader discontinued resus after 20 minutes. Resident: “I thought he needed a resuscitative thoracotomy but no-one was willing to do it. No-one even mentioned it”.



STEPS analysis:
Self – Lacked confidence to speak up, doubted own knowledge or influence
Team – Lack of team situational awareness or knowledge or skill regarding required intervention
System – Insufficient training and preparation for penetrating traumatic cardiac arrest scenario



3. 30-year-old mother with abdominal wound and her 2-year-old daughter with massive open head injury, both due to gunshot wounds, having been shot by husband/father who killed himself on scene. Child arrests in the ED, without ROSC, witnessed by mother before mother is taken to operating theatre.




STEPS analysis:
Patient(s) – tragic case with upsetting circumstances and compounded psychological distress for patient and staff. The best resuscitation team in the world is not going to feel good about this one.



4. 46-year-old previously healthy male with VF arrest achieved ROSC after prehospital defibrillation and brought to the ED of a non-cardiac centre comatose and intubated. Further refractory VF in ED. Received multiple shocks, antiarrhythmics, double sequential external defibrillation. No on-site access to mechanical CPR, cardiac catheterisation, or ECMO. Patient declared dead in ED.



STEPS analysis:
System – Prehospital team gave excellent care but brought the patient to a hospital ill-equipped to manage his ongoing needs, due to lack of ambulance service policy regarding appropriate destination hospital for cardiac arrest cases.



Summary
You can see from the above cases how STEPS may be applied to make some sense of where a resus has gone wrong. Note that I am not recommending this as a way of structuring a team debrief or formal incident investigation – many institutions already have processes for conducting these and various rules and sensitivities have to be accommodated. Rather, this is a format I’ve found helpful in applying during informal discussions that aim to get the nub of where things could or should have gone better.



Occasionally, you can get a case where the STEPS seem to be aligned but things still feel bad – in which the outcome was unsatisfactory because the plan was wrong, or the team wasn’t able to execute the plan. In my next post I’ll discuss another way of analysing cases that can accompany STEPS.



1. Reid C, Brindley P, Hicks CM, Carley S, Richmond C, Lauria MJ, Weingart S.  Zero point survey: a multidisciplinary idea to STEP UP resuscitation effectiveness. Clin Exp Emerg Med. 2018;5(3):139-143
2. Hicks C, Petrosoniak A. The Human Factor. Emergency Medicine Clinics of North America. 2018 Feb;36(1):1–17. 
…