Equipment and Monitoring




© Springer International Publishing AG 2017
Robert S. Holzman, Thomas J. Mancuso, Joseph P. Cravero and James A. DiNardo (eds.)Pediatric Anesthesiology Review10.1007/978-3-319-48448-8_46


46. Equipment and Monitoring



Robert S. Holzman1, 2  


(1)
Boston Children’s Hospital, Boston, MA, USA

(2)
Harvard Medical School, Boston, MA, USA

 



 

Robert S. HolzmanSenior Associate in Perioperative Anesthesia, Professor of Anaesthesia

Email:


Keywords
Cardiac stress testsPulse oximeter technologyCapnography technology and usePressure transducer technologyNear infrared spectroscopy (NIRS)Forced warm air warmersTemperature monitoringBlood warming equipmentImplanted cardiac defibrillators (ICD)Anesthetic vaporizers, thermal considerations


A 13-year-old who developed abdominal pain and claudication was diagnosed with severe mid-aortic syndrome. She is very hypertensive, with calcification and vessel wall thickening of the aorta, bilateral iliac arteries, renal arteries, and the right subclavian artery. She has a severe ascending aortic aneurysm with near complete stenosis of the abdominal aorta at the level of the renal arteries without a distal abdominal aorta or common iliac arteries. In addition, the left common and internal carotid artery is severely narrowed, and the intercavernous extent of the right internal carotid artery is also narrowed. She has claudication with exercise. Meds: amlodipine, metoprolol, minoxidil, and clonidine. VS: 142/92, 86, 16. T 370C. SpO2=99 %

She is scheduled for left thoracotomy, partial left heart bypass, proximal anastomosis, exploratory laparotomy, aortobiiliac bypass with bifurcated graft, and reperfusion and reimplantation of the celiac, superior mesenteric, and left and right renal arteries.


Preoperative Evaluation/Preparation



Questions





  1. 1.


    How will you evaluate the severity of her ischemic disease?


    1. (a)


      Cardiac: Standard Bruce protocol stress test? Dobutamine stress scan? MRA? Cardiac angiogram? Persantine scan? Echo? Can you do a CT angiography and accomplish the same findings in one study? What are you most worried about?

       

    2. (b)


      Peripheral vascular:

       

    3. (c)


      Renal circulation:

       

     


Preoperative Evaluation/Preparation



Answers





  1. (a)


    Cardiac: She will not be able to do a standard treadmill stress test because of her claudication. The results of pharmacologically induced stress testing evaluation by echocardiogram or dipyridamole scanning are acceptable in this circumstance, although exercise stress testing is more accurate. Coronary artery anatomy can be defined by magnetic resonance angiography although she will likely have CT angiography to delineate her vascular anatomy and the coronary arteries will be imaged at the same time.

     

  2. (b)


    Peripheral vascular: The severity of her claudication will provide a major clue to the degree of circulatory impairment, while the imaging studies will confirm the anatomy. The more severe her claudication, the worse her lactic acid level including the rate of rise of lactic acid intraoperatively, especially when she is being revascularized or during bypass.

     

  3. (c)


    Renal circulation: This is of particular concern because it is one of the revascularization sites, which means that it will have to be cross clamped for a period of time. Susceptibility to injury is greater because of the underlying disease.

     


Intraoperative Course



Questions





  1. 1.


    Does this patient need an arterial line? Why/why not?


    1. (a)


      Can you get the same information from a pulse oximeter + end-tidal CO2 analysis? What is the difference?

       

    2. (b)


      How does the pulse oximeter work?

       

    3. (c)


      How does a transducer work?

       

    4. (d)


      Is ETCO2 equivalent to PaCO2?

       

    5. (e)


      Would a TEE add any additional information not otherwise obtainable with the monitors you have in place?

       

    6. (f)


      Any special monitors you would like to have with regard to partial left heart bypass? How does near infrared spectroscopy work? Would it be useful for brain monitoring? Might it be useful in any other organ systems?

       

     

  2. 2.


    She has had a series of cross clamp times that add up to about 5 h in various splanchnic circulations. What consequences would you expect? How would this likely be reflected in your available monitoring devices? Anything else available that you would monitor with? Treat with?

     

  3. 3.


    Is this patient at risk for hypothermia?


    1. (a)


      What is this patient’s ideal intraoperative temperature? Optimal temperature for coagulation and hemostasis? Optimal temperature for organ system function? Optimal temperature for cerebral preservation?

       

    2. (b)


      What are your concerns about choosing a temperature maintenance system? What about her ischemic extremities?

       

    3. (c)


      Are there risks of hyperthermia?

       

     

  4. 4.


    About 3 h into the case, the serum lactate has increased from 2.4 to 5.2 and the temperature is 34.5°C.


    1. (a)


      What do you think is going on?

       

    2. (b)


      What would you need to confirm the diagnosis?

       

    3. (c)


      What will your strategy be? Let’s say the pH is 7.22? 7.15? Is bicarbonate the best choice?

       

    4. (d)


      Would you hyperventilate? Use THAM (tris(hydroxymethyl)aminomethane)? Wait awhile and get another ABG?

       

     

  5. 5.


    The patient is now 33.8 °C.


    1. (a)


      How did this happen?

       

    2. (b)


      Where did it happen?

       

    3. (c)


      What mechanisms of heat loss are most significant?

       

    4. (d)


      Is monitoring of temperature a standard of practice?

       

    5. (e)


      Is it worthwhile putting in a heat and moisture exchanger in the breathing circuit at this time?

       

    6. (f)


      Earlier?

       

     

  6. 6.


    You decide to transfuse, and the nurse brings you cold blood from the refrigerator, which she checks with you to your satisfaction.


    1. (a)


      Now what? How to warm? Why?

       

    2. (b)


      What different methods are available?

       

    3. (c)


      What about filters? How large? What particles? How important?

       

     


Intraoperative Course



Answers





  1. 1.


    The patient definitely needs an arterial line for careful monitoring of blood pressure, blood gases, and additional laboratory data.


    1. (a)


      Although a pulse oximeter and ETCO2 analysis will provide excellent feedback about the quality of oxygenation, ventilation, and circulation, dynamic changes in the circulation as a result of blood loss, exposure requirements with retraction and its effects on contiguous structures, and metabolic monitoring make arterial access mandatory.

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Oct 9, 2017 | Posted by in Uncategorized | Comments Off on Equipment and Monitoring

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