Tag Archives: Critical Illness

EXAMINING THE CRITICALLY ILL PATIENT

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The Critically Ill Patient should receive a systematic head to toe front to back clinical examination each day. Before you start, stand at the end of the bed and take in the scenery. An experienced ICU doctor will acquire an enormous amount of information about a patient by eyeballing the monitor, looking at the patient’s habitus, the machines, the other attached devices, infusion pumps etc.

Then INTRODUCE yourself and explain to the patient, irrespective of level of consciousness, that you are going to examine them, if that’s ok.

Does the patient have an endotracheal tube, nasogastric tube (is it on free drainage?), enteral feeding tube (yellow) or orogastric tube).

Follow the pattern of Inspection, Palpation, Percussion and Auscultation.

Start with the head and evaluate its shape and color. Then move on to the eyes, nose, lips, mouth (inside and outside) and then on to the side of the head and ears.

Move on to the neck – observe for masses, scars and lines (what type of line). Palpate the neck paying particular attention to the trachea (you may want to do a tracheostomy down the line). Feel for crepitus in the supraclavicular area.

Move on to the chest – inspect – look for recent surgical wounds and scars, chest or mediastinal drains, pacemaker wires etc. Observe the breathing pattern – is it symmetrical? Palpate the cardiac apex and the left sternal border. Auscultate for cardiac murmurs, carotid bruits and for breath sounds,  looking for loss of air entry, crackles or bronchial breathing.

Move on from the chest to the arms – are they symmetrical? Is the patient moving both arms? Any redness? What color are the fingers – any mottling? Are the fingertips necrotic? Palpate the arms and hands and feel the temperature – hot or cold? Feel the brachial and radial pulses.

Move on to the abdomen: is it scaphoid or globular? If globular consider the 5 Fs: fat, fluid, flatus, feces, fetus. Are there any scars, wounds or drains? Palpate, percuss and auscultate the abdomen.

Move on to the legs. Are they moving? Are they equal in size? Are the quadriceps wasted? Is there mottling or ischemic changes? Is the patient wearing compression stockings (TED) and or sequential compression devices (SCD)? Palpate the legs, feel the pulses and then look at the ankles (pitting edema) and heels (pressure sores).

Assess the skin – are there any rashes? Are they localized or generalized? If generalized is the rash macular, maculo-papular, vesicular (one side consider herpes zoster) or – ominously purpuric. A generalized purpuric rash is either meningococcemia or thrombotic thrombocytopenia purpura until otherwise proven (both disorders are immediately life threatening).

Roll the patient on their side and look at the back – in particular look at the pressure areas and at any pain catheters and their sites (epidural). Look for the presence of a rectal tube and bowel management system.

When you have completed examination, look at the devices around the bedside sequentially. Start with the main monitor and evaluate the ECG – rate (paced?), rhythm, shape (ST segment changes?). Then the pulse oximeter, arterial blood pressure – invasive and non invasive (correlating?), then the temperature and end tidal CO2 (and waveform).

Move on to the ventilator – if one is attached and note whether the patient is breathing spontaneously or not (why?), what mode (AC, SIMV, BiLevel, PSV), rate, tidal volume, fiO2, PEEP, PFR, plateau pressure, and dynamic compliance and resistance).

Is the patient receiving continuous kidney replacement therapy – note the mode (CVVHDF or SCUF), anticoagulation strategy (citrate or heparin), and fluid removal.

Look for intravenous and enteral feed and take note of the rate and the contents. Then move on to the infusions – iv fluids and electrolyte replacement, analgesics and sedatives, vasopressors, inotropes, insulin and corticosteroids.

Before leaving the bedside look around – did you miss anything and machines or drains or infusions? Then clean up any mess that you have made, restore the bedspace to the condition it was in and inform the nurse of any changes you made or any new observations.

This tutorial has been broken up into two videos to make them easier to navigate.

SIMV-Pressure Control

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This weeks tutorial is on SIMV-Pressure Control. Although this is one of the lesser used modes of ventilation, I sometimes see my colleagues using it in the operating room. And for good reason. Anesthesia ventilators are not set up in the same way as ICU vents. In particular – if you choose “PC” Pressure Control – that is what you get – pressure control; NOT pressure assist control. Hence there is no real provision for patient ventilator interaction. If you choose “SIMV” as pressure control, volume control or volume guaranteed pressure control, then the patient can breath and interact with the ventilator and receive pressure supported breaths. Consequently, conventional SIMV modes, these days, are far more likely to be used in the operating room than in the ICU.

The second reason that I wanted to cover SIMV Pressure Control is to set the groundwork for a different mode “BiLevel Pressure Control” that is built on a similar platform, looks a bit like SIMV, and has significant benefits for those of you who might choose SIMV-PC in ICU.

Most modes of ventilation offer two ways of supporting the spontaneous breath – assist control and SIMV. In SIMV-PC the spontaneous breath can be unsupported, pressure supported or partially supported using Automatic Tube Compensation (ATC). This tutorial covers the type of patient to whom you might deliver SIMV-PC; how to set up the mode; what it looks like on a ventilator screen and the strengths and weaknesses of the mode. @ccmtutorials http://www.ccmtutorials.org

Tutorial 7: Understanding Ventilatory Failure, Alveolar Gas, Lung Volumes and Dead Space.

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Clinicians who work in anesthesiology, intensive care or emergency medicine who are involved in the management of respiratory failure must understand the problem of failure to ventilate: “can’t breathe, won’t breathe.” This long tutorial covers a lot of ground and could be viewed in split sessions.

My principle goal is to give you the tools to work the problem of respiratory failure. Along the way I introduce the alveolar gas equation, ventilation perfusion matching and lung volumes; particularly functional residual capacity. In the second half (from 28:20 onwards), I discuss anatomical and physiological dead space, calculate out the dead space to tidal volume ratio and show how you can be inadvertently increasing physiologic dead space by applying PEEP or neglecting auto-PEEP.

Even if you think you know a lot about this subject, I guarantee that you will learn something.

As always, I welcome feedback.

Don’t Be Scared of Respiratory Physiology – it makes sense (well, most of it anyway!)

Fluids In Hospital Medicine (Part 1)

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Intravenous fluid, fluid management, the physiology of body fluids – all relentlessly controversial and complicated issues. I decided a couple of years ago to put together a course that covers the whole spectrum of fluids – from basic chemistry to basic and advanced physiology, applied physiology, fluid and electrolyte disorders and therapy and acid base chemistry. I will also cover diseases and disorders associated with fluids – either as therapies for, or iatrogenic causes of, disease.

Introduction to the Course

This is a quick introduction to the course, explaining what I am proposing to cover over four parts.

Preliminary Material

This is some really basic chemistry that will allow you to understand the content of subsequent tutorials.

Tutorial 1 Water and Concentrations

This tutorial convers the physical properties of water, what a mole and mmol is and what is g%. I use dextrose as my major example and look at the different ways that glucose concentration is measured in the USA (mg/dl) versus the rest of the world (mmol/L). The end of the tutorial covers the alcohol and calorie content of drinks and drink driving limits.

PART 1 MODULE 1

1 Supplement

I rather like caffeinated drinks and am frequently the subject of sanctimonious comments about my caffeine habit. This tutorial covers caffeine content. Subsequently I look at the issue of 1% versus 2% lidocaine and explain exactly what 1:200,000 epinephrine (adrenaline) is.

Tutorial 2 Salts

This tutorial explains how to calculate out the quantity of electrolytes released from salts as they are dissolved in intravenous fluids. I also take an early look at hypertonic saline solutions.

Tutorial 2 Supplement 1 – More Salt

This tutorial goes through a couple of conundrums where I look at intravenous fluid products and show you how to calculate out the electrolyte contents when you are only given the salts in g/L

Tutorial 2 Supplement 2

This is an early look at calcium supplement products that we typically use in critical care. What exactly is the difference between Calcium Chloride and Calcium Gluconate?

Tutorial 3 Osmosis

Fundamental to understanding how water behaves in body fluids is the concept of osmosis. It is also very important when we visit renal replacement therapies in Part 4 of the course. In this tutorial I use traumatic brain injury and mannitol as my main example.

Tutorial 4 Osmolality and Tonicity

What is the difference between osmolality and osmolarity? What are mOsm? How do you calculate Osmolarity? This tutorial looks at the concept of Osmolality and the Tonicity of intravenous fluids, and why understanding this concept is essential for practitioners of hospital medicine. The clinical scenario is of a patient with hypotonic hyponatremia. I will revisit hypertonic saline solutions and look at the concept of the Osmotic Co-efficient.

Tutorial 5 Electrolyte Distribution

This tutorial looks at the distribution of electrolytes in the body – between the intracellular and extracellular compartments. I look at the needs of a patient who is unable to take oral fluids and electrolytes. I emphasize the importance of maintenance fluids in this situation rather than resuscitation fluids. This tutorial also looks at the interstitial matrix and how it is vulnerable to hydraulic fracturing (“fracking”) caused by intravenous fluids.

This is the end of Module 1.

PART 1 MODULE 2

Tutorial 6 The Adaptive Perioperative Stress Response

Whether we are injured, assaulted or undergo surgery, our bodies respond with an inflammatory response that involves endocrine, metabolic and immune components. The “adaptive” stress response is predictable and its magnitude mirrors the degree of injury. To understand emergency and perioperative medicine and critical illness you must understand the stress response. Having explained the basic physiology, I then go on to discuss fluids and fluid balance and describe the conventional approach (that I do not necessarily subscribe to) to perioperative fluid therapy.

Tutorial 7 Critical Illness and Resuscitation

A patient presents with an “acute abdomen.” His bowel is obstructed and he is losing fluid and becoming both dehydrated and electrolyte depleted. This tutorial looks at the different types of body fluids that may be lost – how they all resemble extracellular fluid and suggests a type of fluid that can be used for resuscitation. I then progress to describing the maladaptive stress response of critical illness, and why it is associated with capillary leak syndrome. There follows a discussion of fluid overload and the need for de-resuscitation. Finally I introduce the topic of chronic critical illness and death.

Tutorial 8 The Macro Circulation

What happens to the body when there is major blood loss? This tutorial looks at the different components of the circulation and how blood flow is redistributed in shocked states. I also look at the assessment of hypovolemic shock, oxygen consumption versus delivery and the mixed venous oxygen saturation. Finally I address resuscitation strategies in acute blood loss.

This ends Part 1 Module 2.

PART 1 MODULE 3 ADVANCES

Tutorial 9 Venous Return

Since the 1970s the venous (and lymphatic) side of the circulation and the right side of the heart seem to have been ignored by doctors. At worst is the widely held belief that central venous pressure represents an appropriate measure of blood volume and resuscitation status. This tutorial looks at the concept of cardiac output versus venous return. I discuss the Guyton concept of mean systemic pressure, the stressed and unstressed blood volume and vascular compliance. I then go on to look at venous return during anesthesia, the impact of low and high dose vasopressors and the impact of fluid overload.

Tutorial 10 The Microcirculation & Capillaries

For the past 125 years or so, the vast majority of clinicians have based their understanding about transendothelial fluid flux on the work of Ernest Starling. Problem is that his hypothesis – the Starling Principle – is wrong. The presence of the capillary glycocalyx and enhanced understanding of fluid kinetics has changed our view of fluid therapy, in particular the role of colloids in treating critically ill patients. This tutorial looks at the capillary network, the traditional Starling method, the “Revised” Starling method, the glycocalyx, oncotic pressure gradients, the impact of fluid extravascation and the lymphatic system.

Tutorial 11 Albumin & Colloids

Colloids, whether they are hydroxyethyl starches, dextrans, gelatins or even albumin, were popular resuscitation fluids until the 2010s. Multiple studies failed to demonstrate the effectiveness of these agents. However, the use of hyperoncotic human albumin solution has gained popularity, based on no real evidence, in recent years. Given our knowledge of the microcirculation, is there any compelling reason to be treating a patient with human albumin solution in the 2020s?

Tutorial 12 Fluid Kinetics

In this last tutorial in Part 1 of this course, we are returning to the operating room. What happens to intravenous fluid once it is injected into the veins a) in normal volunteers, b) during anesthesia, c) during the stress response? This tutorial is all about fluid or volume kinetics and is based on the work of Robert Hahn, from Sweden. I discuss fast versus slow boluses, resuscitation with crystalloid in hypovolemic states, the urinary output during surgery and what happens during hypervolemia.

If you have enjoyed this course, please subscribe on youtube and post lots of likes and positive comments. I will do my best to answer queries and comments below, time permitting.