WE NEED TO REDISCOVER PHYSIOLOGY!

WE NEED TO REDISCOVER PHYSIOLOGY! MERVYN SINGER BLOOMSBURY INSTITUTE OF INTENSIVE CARE MEDICINE UNIVERSITY COLLEGE LONDON, UK

DECLARATIONS OF INTEREST GE Healthcare (manufacturer of Venue ultrasound/echo) Deltex Medical (manufacturer of CardioQ oesophageal Doppler monitor) Oxford Optronix (manufacturer of bladder tissue PO 2 monitor)

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray What would you do? 1. fluid? 2. inotrope? 3. vasodilator? 4. vasoconstrictor?

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 2 l/min, evidence of hypovolaemia

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 2 l/min, evidence of hypovolaemia What would you do? 1. fluid? 2. inotrope? 3. vasodilator? 4. vasoconstrictor?

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 2 l/min, well-filled

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 2 l/min, well-filled What would you do? 1. fluid? 2. inotrope? 3. vasodilator? 4. vasoconstrictor?

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 2 l/min, -filled

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 2 l/min, over -filled

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 2 l/min, over -filled What would you do? 1. fluid? 2. inotrope? 3. vasodilator? 4. vasoconstrictor?

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 12 l/min

post-cardiac arrest, 65 y.o. patient has: HR 130, BP 80/50, CVP 8, lactate 5 mmol/l pulmonary oedema on chest x-ray cardiac output 12 l/min What would you do? 1. fluid? 2. inotrope? 3. vasodilator? 4. vasoconstrictor?

NEED EXTRA INFORMATION TO INFORM CORRECT CHOICE..

NEED EXTRA INFORMATION TO INFORM CORRECT CHOICE.. deeper understanding of physiology

NEED EXTRA INFORMATION TO INFORM CORRECT CHOICE.. deeper understanding of physiology deeper measurement of physiology

Much of our current practice is empiric.. using inappropriate targets.. with little understanding of physiology... or pharmacology... or biochemistry... or metabolism or...

Karl Ludwig (1816-95)

" the fundamental problems in the circulation derive from the fact that the supply of adequate amounts of blood to the organs of the body is the main purpose of the circulation and the pressures that are necessary to achieve it are of secondary importance; but the measurement of flow is difficult while that of pressure is easy so that our knowledge of flow is usually derivatory." Karl Ludwig (1816-95)

BUT THIS IS FOR A POPULATION, NOT AN INDIVIDUAL!!!!!

DRY OR WET?.. HOW ABOUT ENOUGH?

DRY OR WET?.. HOW ABOUT ENOUGH?.. not adapted to individual patient requirement 30 ml/kg is empiric - some patients need more, some less fluid needs to be titrated to a treatment endpoint.. and not an arbitrary amount BALANCED VS UNBALANCED FLUID? monitor chloride levels.. WHAT S THE ISSUE?.. then can safely give NaCl

HOW GOOD ARE YOUR CLINICAL SKILLS?

HOW GOOD ARE YOUR CLINICAL SKILLS? Cardiac output LV filling pressure Connors (NEJM 83) ICU pts 44% 42% Eisenberg (CCM 84) ICU pts 50% 33%

HOW GOOD ARE YOUR CLINICAL SKILLS? Connors Eisenberg Bayliss (NEJM 83) (CCM 84) (BMJ 83) ICU pts ICU pts CCU pts Cardiac output 44% 50% 71% LV filling pressure 42% 33% 62%

HOW GOOD ARE YOUR CLINICAL SKILLS? Connors Eisenberg Bayliss (NEJM 83) (CCM 84) (BMJ 83) ICU pts ICU pts CCU pts Cardiac output 44% 50% 71% LV filling pressure 42% 33% 62% Change in Rx 48% 58% 58%

BLOOD PRESSURE AND HEART RATE INSENSITIVE GUIDES TO CIRCULATORY STATUS

BLOOD PRESSURE AND HEART RATE INSENSITIVE GUIDES TO CIRCULATORY STATUS a normal (or high) BP may mask a low output state hypotension is a late sign of a low output state a low BP may be due to a high output, vasodilated state tachycardia is an almost universal response to stress

J Physiol 1914; 48: 357-79 Ernest Starling (1866-1927)

venous pressure J Physiol 1914; 48: 357-79 cardiac output

FRANK-STARLING CURVE

FRANK-STARLING CURVE 200 ml 200 ml

DOPPLER FLOW VELOCITY WAVEFORM predominant change

DOPPLER FLOW VELOCITY WAVEFORM Preload Reduction Preload Increase predominant change

DOPPLER FLOW VELOCITY WAVEFORM Preload Reduction Preload Increase predominant change Myocardial Depression Positive Inotropy

DOPPLER FLOW VELOCITY WAVEFORM Preload Reduction Preload Increase predominant change Afterload Increase Afterload Reduction Myocardial Depression Positive Inotropy

FRANK-STARLING CURVE STROKE VOLUME END-DIASTOLIC VOL (CVP)

FRANK-STARLING CURVE STROKE VOLUME C B A V1 V2 V3 END-DIASTOLIC VOL (P1 P2 P3) (CVP)

Stanley J. Sarnoff 1917-1990 Chief, Cardiovascular Physiology Lab at the National Heart Institute Physiol Rev 1955; 35:107-22 23

Physiol Rev 1955; 35:123-9

DOSE RESPONSE CURVE IN HEALTHY VOLUNTEERS TO METHOXAMINE (ALPHA-AGONIST) AND METARAMINOL (ALPHA- AND BETA-AGONIST) [from Singer Crit Care Med. 1991;19:1138 45] mean BP (mmhg) 150 130 methoxamine metaraminol 110 90 70-50 -40 60-30 70-20 80-10 90 1000 +10 110 % change in cardiac output

pre-metaraminol post-metaraminol

go dynamic

The physiological challenge fluid dilator posture propofol PEEP..

PROTOCOLS VS GUIDELINES

SUMMARY Physiology is fundamental to good - personalised - patient care Protocols appropriate for processes of care. but not personalised patient management