Neuro Resus

Basic Science Clinic by Steve Morgan

Among the notable things about fire is that it also requires oxygen to burn - exactly like its enemy, life. Thereby are life and flames so often compared.

- Otto Weininger

Welcome to the second podcast in the Basic Science Clinic Raw Science series. In our somewhat circuitous exploration of respiratory physiology we will complete the story of the promiscuously electronegative pharmaceutical gas oxygen.

In the first episode of this series we addressed the 'why' of oxygen, exploring its unique physicochemical properties to explain its onerous position as the foundational slab of our hierarchy of needs. Having traced our way from the presence of oxygen in the atmosphere to the ETC at a mitochondrial level, we now move to the 'how' of oxygen. In this second podcast we return to the atmosphere, examining the contributors to the gaseous composition, as both a signature and supporter of complex biology, and the morphological adaptations necessary to successfully interface with the atmosphere to harvest its oxygen content.

As always, we would love to hear feedback/corrections and are happy take requests for content of future podcasts.

Raw Science Factoids

1. The size and consequent gravitational force of the inner rocky planets imposes relatively low escape velocities (on Earth it's 11 km/s) meaning they are unable to retain the abundant, light elemental gases hydrogen and helium. Venus and the Earth are nearly the same size while Mars is less than half the size of Earth. Venus and Mars have atmospheres dominated by CO2. Earth, uniquely in our solar system, retains an atmosphere composed predominantly of N2 and O2.
2. Earth formed 4.6 billion years ago from the gravitational accretion of a broiling mixture of interstellar gases and dust. At this stage it had almost no atmosphere and the surface was molten. As Earth cooled, an atmosphere formed mainly from gases spewed forth from active volcanoes.
3. 7 billion years ago, blue-green cyanobacteria flourished in the Earth's oceans. They made gaseous, or free, oxygen by the photolysis of water, utilising the abundant energy source of ubiquitous UV light.
4. Until about 430 million years ago, most aerobic organisms lived in the ocean and exploiting oxygen dissolved in seawater. Terrestrial life then appears in the form of small plants and invertebrates that had evolved the ability to harness oxygen in the gas phase directly from the atmosphere.

Basic Science Clinic by Steve Morgan

Assume nothing, trust no one, give oxygen.

– Anon

Welcome to Basic Science Clinic Raw Science podcast series. In case you haven't being paying attention, science is cool. Indulge your inner geek by joining us on our pursuit of developing an integrated scientific understanding from which you can develop a clinical practice informed by deeper insights and inoculation against magical thinking.

We are going to take an unashamedly convoluted journey from atmospheric gas to the mitochondria and back again, to examine respiratory physiology and hopefully frame the information in a format that helps you on your inexorable march to examination success.

Have you ever asked yourself what is all the fuss about oxygen? In the first two podcasts we are going to address why oxygen is the foundational slab of our hierarchy of needs and how it got here in the first place. It might just give you a renewed appreciation of nature's most vital pharmaceutical.

We would love to hear feedback and we will even take requests from the floor for future subjects. Apologies for any mistakes, we are always happy to learn so corrections are most welcome.

Raw Science Factoids

1. 2 x 1026 molecules of ATP formed daily, or ~160kg from 2500 calories.
2. At any one time there is 50g of ATP in the body, cells contain ~1 billion ATP molecules, utilize 2 million ATP/s, regenerating ~600 ATP/s.
3. On average we breath ~400 L O2/day and at rest consume ~350 L O2/day.
4. Oxygen is the third most abundant element in the universe, and the most abundant by mass in the Earth's biosphere.
5. Increased solubility is evidenced by the increased density of life in the polar oceans.

Basic Science Clinic by Steve Morgan & Sophie Connolly

All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.

Immanuel Kant

Welcome to Basic Science Clinic Crit Think. Our Raw Science series is to provide content for the new programs that you are writing for your intracranial wet-wear, Crit Think is the upgrade of your operating system. The study and understanding of the process, structure and potential pitfalls of thought, ie thinking about thinking or metacognition, helps you to integrate the knowledge you are acquiring and then apply it with scientific rigor, making you a safer, skeptical, rational bedside empiricist. Create the good habits of data seeking and analytics to emulate the best consultants, with their granular, high fidelity knowledge and their near preternatural ability of pattern recognition that leads to the right intervention just in a nick of time.

This series will include mathematics, what latin is to language, maths is to science. Without maths there is no science; and go on to cover: logic, reasoning and logical fallacies; the art of clinical decision making, heuristics, cognitive biases; educational theory; introduction to ethical principles. In the informational age, with ready available knowledge on the end of a digital swipe, there is an even greater imperative that in your nascent development as a clinician you consider these key components of the structure of your most potent, yet potentially deceptive tool, for knowledge application and making critical decisions over seconds to minutes that may be life-saving.

Paul Young is the man of the moment.

In one week has has published the SPLIT trial in JAMA, the HEAT trail in the NEJM and presented both at the ESICM conference. Platform Trials.

In this interview Paul discusses The SPLIT Trial - the first trial to substantially look at buffered crystalloids vrs saline and now really paves the way for a definitive trial in this area.

He answers some questions that have been asked such as was the volume of fluid sufficient to demonstrate an effect, why PlasmaLyte was used and what he’ll be doing following these results.

HEAT is a much anticipated trial looking at the effect of early administration of acetaminophen to treat fever due to probable infection. This intervention did not affect the number of ICU-free days. Paul captured out imagination on this topic with a talk at SMACC in 2013 and now the dialogue really begins. We discuss where to go from here on this topic that often stimulates passionate debate…

Finally we discuss Platform trials and how they will save the world. This was topic of a talk Paul gave in Chicago which will be released soon. Read this fascinating paper by Berry Connor and Lewis for a real insight into the hot topic.

Grace Leo shares her cornerstones for developing a powerful presentation: passion, purpose and practice. In this workshop talk from smaccGOLD, she also provides tips and strategies to turn an average presentation into one with style. For the full post, please see www.intensivecarenetwork.com

A personal story of cyclone Yasi

The beginning of 2011 was an extraordinary period for natural disasters in our part of the world. It began with the floods in South East Queensland, then Cyclone Yasi, the Christchurch earthquake and finally the Japanese tsunami.

The evacuation of the Cairns Hospital in less than 24 hours is one of the great success stories for Emergency Services in Queensland. It is even more extra-ordinary when one realizes there was no formal evacuation plan for Cairns Hospital in place. Many health professionals put aside their personal welfare and concerns for their own homes to ensure that 320 patients were evacuated without a single fatality. Special mention should be made of those that weathered the Category 5 winds (over 250 km/hr) in the stand-alone basketball stadium that served as the ‘hospital’ for 250,000 people post Cairns Hospital shutting down.

This presentation by Dr Sean McManus outlines an exhausting 96 hours. Firstly managing the evacuation of ten ventilated patients from the Cairns Intensive Care Unit, then packing up his house and bunkering down for the storm and then finally dealing with a critically unwell 5 month old with complex cardiac pathology.

“Polepole”, the Swahili motto for climbing Kilimanjaro is a consistent theme throughout the presentation. Translated as ‘steady, steady’, it means just keep taking little steps until you reach the summit and don’t let the enormity of the mountain overwhelm you.

Bloody Oral Anticoagulants – BCC talk 2014

The use of the New Oral Anticoagulant Drugs present unique challenges for the Intensive Care practitioner

1. The NOACs now have PBS approval for non-valvular AF, below knee DVT, DVT prophylaxis and low volume PE

2. There is no specific antidote for NOAC related bleeding but don’t despair there are some things that can help

3. Routine coagulation testing does not reflect drug levels or anticoagulation activity

Global sales of Dabigatran topped $1billion in 2012.

This talk outlines the pharmacodynamics and pharmacokinetics of the NOACs. Limitations and cautions of use are outlined with a review of the extensive literature. Clinical cases involving the NOACs are presented. The timing of stopping the agents before minor or major surgery, the approach to a patient with intracranial haemorrhage taking oral anticoagulants and the challenges faced when patients have an Acute Kidney Injury whilst taking these

Neurotrauma – How to Put Humpty together again

Humpty is a 23 year old egg, who fancied himself as a bit of a Hipster. Little did poor old Humpty know that his day was about to end in tears and he was to join the 1000 other Australians who annually have a severe head injury.

The talk focuses on Traumatic Brain Injury. There is particular emphasis on Traumatic Subarachnoid Haemorrhage and Transfusion Thresholds in Traumatic Brain Injury.

The discussion explores the incidence and patterns of vasospasm following tSAH and the role, if any, of nimodipine and other therapies usually reserved for the aneurysm SAH population

The optimal target haemoglobin concentration following TBI is unknown. The discussion looks at the literature and explores the pathophysiology of anaemia in this setting. A blood conservation strategy for patients with TBI is outlined

Penetrating injuries to the neck is a great summary of how to assess and manage neck wounds from lacerations to the airway to gunshot wounds. The talk covers relevant anatomy, the zones of the neck and how to investigate vascular, tracheal and oesophageal injuries. A comprehensive understanding of the relevat anatomy is essential to recognising associated injury patterns. The improvements in the accuracy of helical CTA scans has meant that the delineation of the zones of the neck has become less relevant to the further investigation and management of pemetrating neck wounds. Oesphageal injuries remain difficult to detect and require a high level of clinical suspicion to identify these.