Hi, myself and my peer group just wanted to check we are on the right lines with our answer to Activity 36 regarding the trends in Daisy's observations and what has been happening to her.

What stood out to us was:

At 18:00 her vent set rate was lower than it was at the hours that followed (18:00 was when her PEWS score was raised)
Her 18:00 blood gases showed high lactate levels (anaerobic metabolism/metabolic acidosis) and also her calcium levels were low (reduced contractility to the heart) - can her tachycardia be caused by this as her heart is working harder due to the decreased contractility? Also are her high lactate levels a sign she is hypoxic due to the reduced contractility caused by decreased calcium levels as her heart isn't pumping blood around the body as effectively?
At 18:00 her CO2 levels are high (respiratory acidosis) - Triggering chemoreceptor response - increasing rate and depth of breathing.
When her vent set rate increased her lactate levels decreased
At 19:00 her BP begins to decrease slightly. At this time she has significant drain losses and a dose of milrinone.

Are we on the right lines with this? Sorry for the extremely long-winded question/s! 

Hi, myself and my peer group just wanted to check we are on the right lines with our answer to Activity 36 regarding the trends in Daisy's observations and what has been happening to her.

What stood out to us was:

At 18:00 her vent set rate was lower than it was at the hours that followed (18:00 was when her PEWS score was raised)
Her 18:00 blood gases showed high lactate levels (anaerobic metabolism/metabolic acidosis) and also her calcium levels were low (reduced contractility to the heart) - can her tachycardia be caused by this as her heart is working harder due to the decreased contractility? Also are her high lactate levels a sign she is hypoxic due to the reduced contractility caused by decreased calcium levels as her heart isn't pumping blood around the body as effectively?
At 18:00 her CO2 levels are high (respiratory acidosis) - Triggering chemoreceptor response - increasing rate and depth of breathing.
When her vent set rate increased her lactate levels decreased
At 19:00 her BP begins to decrease slightly. At this time she has significant drain losses and a dose of milrinone.

Are we on the right lines with this? Sorry for the extremely long-winded question/s!                                                                                                                                                                                      Hi there, first of all, this is a really well thought out answer and I am really impressed with the depth of knowledge you all have. In this case lets think about what Daisy had done when those observations were documented. Daisy had just returned from theatre and her body is very likely in what we call a stress response, where basically the body is in a flight or fight response due to having surgery.                                You are quite right about the rate of breathing being low, and this potentially had an impact on her carbon dioxide. Carbon dioxide is very acidic as a substance, so this could have made her blood gas acidic as a result if we look at the hydrogen ions - our marker for acidosis or alkalosis. Also can you see what Daisy is on medicine wise? She is still on Rocuronium, Midazolam and Morphine, which means that the ventilator will be doing all the breathing for Daisy. The set rate was most likely set too low and as you correctly identified, when the set rate rose, that had an impact on the Carbon dioxide level.                                                                                                                                                                                     And you were correct to identify that there is also some metabolic acidosis occurring because her bicarbonate and base excess are low, therefore meaning buffering agents are not being produced. The key is to think, where do these buffering agents come from. It is one of many functions that our kidneys have, to maintain acid-base balance by releasing buffering agents such as bicarbonate. So there is a possibility that our kidneys function has slowed down, possibly due to fluid loss or an after effect of being on cardio-pulmonary bypass.                                                                                                             When you see the fluid chart at 19:00, you see that a Gelofusine bolus was given, and this, as well as the rate change you correctly identified, would have helped that lactate level come down, because the kidneys have been nourished with more blood volume and oxygen so they can function better to clear that acidosis. Also at 19:00, on the Ventilation chart above the blood gases did you see a P and 2M. This means that Daisy has just had physio on her chest. So she probably had some secretions that was affecting her gas exchange ability.                                                                                                                             I personally wouldn't be concerned with her calcium level as that is at a normal level, but well done for identifying the importance of looking at that calcium level, as it does influence contractility of the heart. And yes the BP most likely dropped a little due to that drain loss that she had so well done for spotting that.                                                                                                                                                               I hope that helps, as you can see there are so many possibilities that it could be, and your answer was not incorrect, it had lovely rationale that would have gained marks if you wrote something like that in the exam. So really well done for the effort :)                                                           

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