BT_PO 1.50 Describe the cardiovascular changes that occur with morbid obesity


I know those guys guys above are highly trained athletes, but…..

BT_PO 1.50  Describe the cardiovascular changes that occur with morbid obesity

This topic is not well covered in the standard primary exam texts. A textbook previously on the primary examination reading list, Foundations of Anaesthesia , had a whole chapter (Ch 71) devoted to the topic. Unfortunately, the new iteration of the book, Pharmacology and Physiology for Anaesthesia by Hemmings and Egan (a great book to look at), has dispensed with the subject – drats!!

The ANZCA library has three ebooks devoted to the peri-operative management of the morbidly obese. Each of these books has sections detailing the basic alterations of physiology associated with obesity. The most comprehensive of these is Morbid obesity: perioperative management 2e edited by Alvarez et al.

For those of you without access to the ANZCA library, here is a overview of some of the issues, from the little CME journal produced by the same group as the BJA.

Cardiac output increases linearly in proportion to free fat mass          TRUE/FALSE

Blood volume on a mL/kg bases is increased in the morbidly obese    TRUE/FASLE

Left ventricular hypertrophy (LVH) is common in morbid obesity, even in the absence of hypertension      TRUE/FALSE

Standard ECG criteria for diagnosing LVH are valid in morbid obesity   TRUE/FALSE

Angiotensinogen is produced by visceral adipocytes resulting in excessive angiotensin II TRUE/FALSE

2017.1 : SAQ 10

I’m skipping over SAQ 9 as I covered it on December 5 last year.

Draw both aortic root and a radial artery pressure wave forms on the same axes.  Explain the differences between them.

It’s important to realise that the vessels of the circulation are not just a passive conduit – systemic pressure waveforms are produced by an interaction of the left ventricle, arterial physical properties and characteristics of the blood

Tapering contributes to the higher peak pressure seen in the radial artery   TRUE/FALSE

Reflection contributes to the diastolic hump seen in the radial artery  TRUE/FALSE

Stiff vessels will transmit reflected pressure waves faster  TRUE/FALSE

Mean pressure is higher in the radial artery  TRUE/FALSE

The Bernoulli effect created by a slower flow rate when the aortic valve closes creates the incisura  TRUE/FALSE




SS_PA 1.24 : paediatric physiology

Not a bad textbook, Evers & Maze… But rubbish for paediatric pharmacodynamics… So I’ve swapped over to some paediatric physiology instead. I used Miller as it was handy.

SS_PA 1.24 Describe the physiology of the cardiovascular, respiratory, renal and neurological systems in the neonate and the changes that occur with growth and development and the implications of this for anaesthetic care

During the first 2 weeks of age a neonate can flip back into a foetal circulation   TRUE/FALSE

The neonate has more compliant ventricles than an adult   TRUE/FALSE

Infants have more type I muscle fibres in their diaphragm   TRUE/FALSE

Neonates have decreased intracardiac calcium stores   TRUE/FALSE

Oxygen consumption in infants is higher than in adults   TRUE/FALSE

BT_PO 1.49 Describe the cardiovascular changes the occur with ageing 

april 2004 049My elder daughter turns 15 today.

She is now able to tie her own shoelaces, and fit those boots.

I don’t think she needs to worry about the today’s LO. Me on the other hand……..

BT_PO 1.49 Describe the cardiovascular changes that occur with ageing

Ageing causes a decreased number of sinus node cells in the heart, leading to decreased B adrenergic sensitivity T/F

The velocity of the transmitted pulse wave in the vasculature tends to be slower in the eldery T/F

Elderly have higher levels of baseline sympathetic nervous system activity T/F

The atrial component of ventricular filling is especially important in the elderly T/F

Older patients often have an increased arterial pulse pressure due to reduced vascular compliance T/F

SS_PA 1.21 Describe the foetal circulation

Within the umbilical cord, there are two veins, and one artery. TRUE / FALSE

Foetal blood returning from the placenta has an oxygen saturation of 80%. TRUE / FALSE

The foramen ovale remains open in the foetus under the influence of prostaglandins. TRUE / FALSE

The ductus arteriosus adds blood into the aorta distal to the vessels supplying the brain. TRUE / FALSE

Following delivery, there is a “transitional” circulation. Target SpO2 levels for a neonate are: 70-90% at 3 mins, and 85-90% at 10 mins. TRUE / FALSE

BT_PO 1.48 Intergration of cardiovascular responses part 2

When I was writing yesterday’s post, I forgot that today would be Saturday ( that is what comes from being on sick leave and having children on holiday😉). Lucky you – an extra post this week!

BT_PO 1.48 Discuss the cardiovascular responses to:
· Changes in posture

· Exercise

· Valsalva maneouvre

· Positive pressure ventilation and PEEP

· Pneumoperitoneum

· Haemorrhage and hypovolaemia

· Surgery and trauma

The blood volume impacts on the cardiovascular responses of a patient undergoing the Valsalva Manoeuvre  TRUE/FALSE

Pneumoperitoneum with an intraabdominal pressure of greater than 10mmHg is likely to result in an increase in cardiac output TRUE/FALSE

Compensation which occurs following haemorrhage, aims to restore arterial blood pressure to normal TRUE/FALSE

Sympathetic stimulation associated with major haemorrhage results in significant coronary artery constriction TRUE/FALSE

The baroreceptor setpoint changes during excersice TRUE/FALSE

BT_PO 1.48 Integration of cardiovascular responses

Sticking with CVS physiology, another LO highly represented in the exam. I think I will stick with this topic tomorrow as well – stay tuned for part 2…

BT_PO 1.48 Discuss the cardiovascular responses to:
· Changes in posture

· Exercise

· Valsalva maneouvre

· Positive pressure ventilation and PEEP

· Pneumoperitoneum

· Haemorrhage and hypovolaemia

· Surgery and trauma

Coronary blood flow may increase 4 times resting level during heavy exercise TRUE/FALSE

The cardiac output during exercise is higher than that calculated on heart rate and increased contractility alone TRUE/FALSE

1000 ml of interstitial fluid can be absorbed during shock during the first hour TRUE/FALSE

The Valsalva Manoeuvre can be used to test the integrity of the baroreceptors TRUE/FALSE

A cerebrally mediated activation of the sympathetic nervous system occurs when the arterial pressure falls below 50 mmHg TRUE/FALSE

BT_PO 1.45 Cardiac output

No pictures today, just an LO which features heavily in the SAQs and vivas.

BT_PO 1.45  Discuss the factors that determine and control cardiac output and the implications for clinical practice including:          
· Preload, afterload and contractility

· The Frank-Starling mechanism

· Cardiac output and vascular function curves

· Pressure volume relationships in the heart

The heart only has to work against afterload once the aortic and pulmonary valves are open and ejection of ventricular blood begins TRUE/FALSE

If afterload and contractility remain unchanged, increasing preload will result in a decreased end-systolic ventricular volume TRUE/FALSE

In sinus rhythm, atrial contraction contributes about 30% to the end diastolic ventricular volume TRUE/FALSE

A Frank Starling curve relates ventricular end diastolic volume to left ventricular pressure TRUE/FALSE

In normovolaemic patients, IPPV causes an increase in cardiac output TRUE/FALSE