Principles of Surgery (POS)Critical Care Review

D.Kubelik University of Ottawa

POS Lecture Series 2012

Adapted from D.Kim

Objectives

review ATLS principles

discuss basic physiologic concepts as applicable to critical care/ICU

apply these principles to case based scenarios

Critical Care

Cardiac Physiology

PAWP ~ Left atrial pressureCVP ~ Right atrial pressure

Exams

Approaches to questions that give central pressure data Is the heart working well?

Use the cardiac index/cardiac output If the CO is high look for distributive causes of shock

If CO is low where is the problem Look at where pressures are increasing This is usually proximal to the disease

E.g. PE high RV and CVP but normal wedge

Shock

Approach to a hypotensive patientMAP = CO x SVR

Decreased SVRSepsisNeurogenic ShockAdrenal InsufficiencyLiver FailureAnaphylaxisMedications

Decreased Cardiac Output

Classifying Shock

HypovolemicCardiogenicObstructiveDistributive(Endocrine)

Can have cardiogenic or distributive components

A 51 YO patient with known lung cancer undergoing radiation therapy presents to the hospital with worsening shortness of breath. He becomes hypotensive and gets admitted to the ICU. He has a CI of 1.9, CVP 20, PAWP 20, RV pressures 35/20 PA pressures 32/20. What is the most likely diagnosisPEMIPneumonia and sepsisCardiac Tamponade

Tamponade

Intrapericardial pressure equalizes and opposes atrial and ventricular pressures

Hypotension, tachycardia, high CVP and pulsus paradoxus (drop >10mmHg in pressure with inspiration)

A 51 YO patient with known lung cancer undergoing radiation therapy presents to the hospital with worsening shortness of breath. He becomes hypotensive and gets admitted to the ICU. He has a CI of 1.9, CVP 18, PAWP 10, RV pressures 50/33 PA pressures 50/20. What is the most likely diagnosisPEMIPneumonia and sepsisCardiac Tamponade

Treatments

1. Which of the following is/are not a determinant of CO?

a) end-diastolic pressure

b) afterload

c) contractility

d) heart rate

e) ventricular interaction

Key Equations

CO = HR x SV

SV = EDV – ESV

EF = SV / EDV

MAP = CO x SVR

Frank-Starling

2. Which of the following mechanisms are the body’s most important defenses in severe oxygen transport deficiency?

a) hyperventilation

b) reduction of VO2

c) organ redistribution of CO

d) shifting of the O2 dissociation curve

e) widening of the a-v O2 content

The oxyhemoglobin dissociation curve relates the partial pressure of O2 in the blood (PO2) to the % saturation of hemoglobin with oxygen (SO2). For a given SO2, the PO2 depends on all of the following, EXCEPT?

1) temperature

2) serum potassium

3) pH

4) RBC content of 2,3-DPG

Hemoglobin-O2 Dissocation Curve

Remembering the dissociation curve

A shift to the right means oxygen is unloaded

“Exercising muscle needs oxygen” Increased temp, CO2,

acidosis, glycolysis 2,3 DPG is a glycolysis

breakdown product Compare curves for a set pO2

3. What is the definition of the shock state?

a) low BP to maintain normal metabolic and nutritional metabolism

b) low CO to maintain normal metabolic and nutritional metabolism

c) inadequate tissue perfusion to maintain normal metabolic and nutritional metabolism

d) abnormal vascular resistance to maintain normal metabolic and nutritional metabolism

DO2-VO2 Equations

4. In which of the following is CVP a reliable guide in fluid management?

a) CXR with pulmonary edema

b) RVEDP = CVP

c) MV disease

d) LVEF = 0.4

e) PHTN

CVP and PCWP

5. Which of the following are determinant of mixed venous O2 saturation (SvO2)?

a) VO2

b) CO

c) Hb Concentration

d) arterial O2 saturation

e) myocardial VO2

6. Which of the following is/are associated with en elevated SvO2?

a) septic shock

b) distal migration of the PAC

c) lactic acidosis

d) left-to-right shunt

e) right-to-left shunt

7. Regarding CO2 kinetics, which of the following is/are true?

a) total amount of CO2 produced is equivalent to the total amount of O2 consumed

b) the a-v difference of CO2 is the same as O2

c) end-tidal CO2 is the same as paCO2

d) all of the above

CO2 metabolism

8. Which of the following is/are associated with increased dead space ventilation?

a) low CO

b) ARDS

c) PE

d) PHTN

e) all of the above

9. With regards to ventilatory mechanics, which of the following statements is/are true?

a) WOB consume 2% of total body O2 consumption

b) WOB may increase to 50% in the postop patient

c) the increased WOB in COPD is due primarily to an increased inspiratory effort

d) airway pressure reflects the compliance of the chest wall and diaphragm as well as the lungs

e) C = V / P

Compliance & Resistance

10. Which of the following indicates the need for immediate ventilatory support?

a) RR > 35bpm

b) paCO2 >60mmHg

c) A-a O2 gradient > 350mmHg

d) VD/VT >0.6

e) shunt fraction greater than 5%

11. ARDS is characterized by:

a) bilateral pulmonary infiltrates

b) paO2/FiO2 <300mmHg

c) PCWP >18mmHg

d) hypoxemia with hypercarbia

e) increased dead space ventilation and increased lung compliance

12. Which of the following treatment are appropriate for the ARDS patient?

a) MV

b) albumin and Lasix

c) PEEP

d) ECMO

e) routine steroids

13. With regards to FRC, which of the following is/are true?

a) FRC = RV + TV

b) atelectasis occurs when the FRC falls below the closing volume (CV)

c) FRC = ERV + RV

d) FRC is increased by PEEP

PFTs

14. Which of the following may be seen with shock?

a) hyperglycemia

b) negative nitrogen balance

c) lactic acidosis

d) metabolic alkalosis

e) hyperkalemia

15. 24yo female undergoes ex lap for a Class IV hemorrhage and is transfused >12U PRBCs. Which of the following is most appropriate?

a) CaCl

b) FFP

c) plt

d) correction of hypothermia

e) heparin

Trauma

Primary Survey

22yo male post-MVC, combative, pale, bleeding profusely from nose and mouth

R thigh deformity and scalp laceration BP=80/40; HR=130; RR=40

Which of the initial management options is correct?

a) esophageal intubation, rapid infusion RL 2L via CVC, traction, suture scalp

b) ETT, rapid infusion RL 2L via 2 peripheral IVs, traction, suture scalp, exposure

c) O2 by mask, rapid infusion RL 2L via 2 peripheral IVs, traction, pressure scalp, exposure

d) cricothyroidotomy, rapid infusion RL 2L via 2 peripheral IVs, traction, pressure scalp, exposure

e) jaw thrust, rapid infusion RL 2L via 2 peripheral IVs, traction, suture scalp, exposure

32yo female jumper from 10th floorhead and extremity injuriesapneic in ED

By which method is a definitive airway provided for this patient?

a) orotracheal intubation

b) nasotracheal intubation

c) cricothyroidotomy

d) needle cricothyroidotomy

\

22 yo male automobile firecarbonaceous sputum, stridorfailed nasotracheal intubationO2=97%

Prior to orotracheal intubation, what step(s) is/are correct?

a) preoxygenation via high-flow O2

b) cricoid pressure

c) prepare for crico

d) axial stabilization

e) all of the above

56yo male ped struckmultiple facial lacs, profuse bleeding

from nose and deformed mandibleperiorbital swelling and inability for

upward gazeRR=40, stridor, anxious

What is the appropriate next sequence?

a) O2, CT, suture, lateral c-spine

b) nasotracheal intubation, posterior packing, lateral c-spine, CT face

c) endotracheal intubation, posterior packing, lateral c-spine, CT scan of face

d) endotracheal intubation, posterior packing, lateral c-spine, x-ray face

e) posterior packing, endotracheal intubation, lateral c-spine, CT scan of face

22 yo male stab along ant. border of SCM 1 cm sup. to cricoid

platysma penetratedVSS

Which of the following management option(s) is are correct?

a) admit to ICU and observe for airway obstruction and expanding hematoma

b) perform carotid angio(graphy), if normal, observe

c) perform carotid angio, barium swallow, rigid esophagoscopy, if normal, observe

d) explore neck

e) perfrom carotid angio, barium swallow, flexible esophagoscopy, if normal, observe

24 yo male unrestrained driver MVChypoxic despite O2CXR - bilateral chest infiltrates

Which of the following in the most likely diagnosis?

a) bilateral pneumonia

b) ARDS

c) aspiration pneumonia

d) atelectasis

e) pulmonary contusion

Which of the following modalities in the most important for identifying patients at risk for complications from myocardial contusion?

a) serial CK and TnI

b) ECG

c) echo

d) spiral CT

e) cardiac angio

40 yo male stab to left 7th intercostal in the anterior axillary line

clinically stable, clear BS bilatCXR - no ptx, no hemo

Which of the following statement(s) is/are true?

a) absence of hemo/pneumo indicates that the pleural cavity was not entered

b) absence of hemo/pneumo rules out intraabdominal injury

c) if the pat. is to have GA, he must first undergo a left sided chest tube insertion

d) further evaluation should be carried out to rule out intraabdo. injury

30 yo male stab wound to right mid-infraclavicular region

weak pulse in bus 10 minutes agonow, no pulse or BP in ED with reactive

pupils

What is the initial surgical approach of choice?

a) median sternotomy

b) right sided cervical incision

c) right sided clavicular incision

d) right anterolateral thoracotomy

e) left anterolateral thoracotomy

22yo female stab to left 5th ICS in MCLBP=70/40; HR=140; RR=35JVD-normal; trachea midline; muffled

HS; decreased BS on the left

Which of the following is/are possible diagnosis?

a) pericardial tamponade

b) massive left hemo

c) tension ptx

d) flail chest

e) a, b, and c

28yo unrestrained driver in MVCVSS and LUQ tenderness with no

peritonitis

What is the next step in management?

a) ex lap

b) diagnostic peritoneal lavage (DPL)

c) admit for obs

d) CT abdo/pelvis

e) focused assessment using sonography for trauma (FAST)

47yo male high speed MVCVSS, multiple rib fractures and L femur #PCXR (insert)

Which of the following is/are most appropriate for evaluation?

a) admit, observe, repeat CXR 6-8 hrs.

b) immediate aortography

c) CT thorax with contrast

d) L anterolateral thoracotomy

e) b and c

Which of the following is/are indications for emergent angiography in hemodynamically unstable patients with a pelvic ring fracture?

a) grossly negative findings on DPL

b) micro. positive findings

c) grossly negative findings on DPL and continued bleeding requiring ongoing transfusion

d) stable patient with an expanding hematomta

Regarding liver trauma, which of the following statements is/are true?

a) NOM is Rx of choice in stable pt. with isolated hepatic injury

b) the Pringle maneuver can be performed for up to 90 min. without ischemic sequelae

c) subcapsular hematomas discovered intraop should always be explored

d) finger fracture technique for deep lacs is ineffective

e) intraop packing, rapid closure, and resuscitation in the ICU has led to an increased mortality

27yo male suffers severe blow to headVSS, breathing spontaneouslyopens eyes to voice; mumbles words;

withdraws to pain

Which of the following is/are indicated in the initial evaluation and stabilization?

a) CT head

b) ETT and hyperventilation

c) ICP monitoring

d) burrhole on the right side

e) A, B, C

Which of the following is/are true re: peripheral arterial injuries?

a) all patients have diminished or no pulses distal to the extremity

b) if the injury cannot be repaired primarily, a prosthetic interposition graft should be used

c) all patients with post. knee dislocations should undergo popliteal angio

d) compartment syndrome is a contraindication to angiography

e) completion angio. is not necessary after the insertion of an interposition graft if distal pulses are present

Critical Care

Cardiac Physiology

PAWP ~ Left atrial pressureCVP ~ Right atrial pressure

Exams

Approaches to questions that give central pressure data Is the heart working well?

Use the cardiac index/cardiac output If the CO is high look for distributive causes of shock

If CO is low where is the problem Look at where pressures are increasing This is usually proximal to the disease

E.g. PE high RV and CVP but normal wedge

Shock

Approach to a hypotensive patientMAP = CO x SVR

Decreased SVRSepsisNeurogenic ShockAdrenal InsufficiencyLiver FailureAnaphylaxisMedications

Decreased Cardiac Output

Classifying Shock

HypovolemicCardiogenicObstructiveDistributive(Endocrine)

Can have cardiogenic or distributive components

A 51 YO patient with known lung cancer undergoing radiation therapy presents to the hospital with worsening shortness of breath. He becomes hypotensive and gets admitted to the ICU. He has a CI of 1.9, CVP 20, PAWP 20, RV pressures 35/20 PA pressures 32/20. What is the most likely diagnosisPEMIPneumonia and sepsisCardiac Tamponade

Tamponade

Intrapericardial pressure equalizes and opposes atrial and ventricular pressures

Hypotension, tachycardia, high CVP and pulsus paradoxus (drop >10mmHg in pressure with inspiration)

Treatments

1. Which of the following is/are not a determinant of CO?

a) end-diastolic pressure

b) afterload

c) contractility

d) heart rate

e) ventricular interaction

Key Equations

CO = HR x SV

SV = EDV – ESV

EF = SV / EDV

MAP = CO x SVR

Frank-Starling

2. Which of the following mechanisms are the body’s most important defenses in severe oxygen transport deficiency?

a) hyperventilation

b) reduction of VO2

c) organ redistribution of CO

d) shifting of the O2 dissociation curve

e) widening of the a-v O2 content

The oxyhemoglobin dissociation curve relates the partial pressure of O2 in the blood (PO2) to the % saturation of hemoglobin with oxygen (SO2). For a given SO2, the PO2 depends on all of the following, EXCEPT?

1) temperature

2) serum potassium

3) pH

4) RBC content of 2,3-DPG

Hemoglobin-O2 Dissocation Curve

Remembering the dissociation curve

A shift to the right means oxygen is unloaded

“Exercising muscle needs oxygen” Increased temp, CO2,

acidosis, glycolysis 2,3 DPG is a glycolysis

breakdown product Compare curves for a set pO2

3. What is the definition of the shock state?

a) low BP to maintain normal metabolic and nutritional metabolism

b) low CO to maintain normal metabolic and nutritional metabolism

c) inadequate tissue perfusion to maintain normal metabolic and nutritional metabolism

d) abnormal vascular resistance to maintain normal metabolic and nutritional metabolism

DO2-VO2 Equations

4. In which of the following is CVP a reliable guide in fluid management?

a) CXR with pulmonary edema

b) RVEDP = CVP

c) MV disease

d) LVEF = 0.4

e) PHTN

CVP and PCWP

5. Which of the following are determinant of mixed venous O2 saturation (SvO2)?

a) VO2

b) CO

c) Hb Concentration

d) arterial O2 saturation

e) myocardial VO2

6. Which of the following is/are associated with en elevated SvO2?

a) septic shock

b) distal migration of the PAC

c) lactic acidosis

d) left-to-right shunt

e) right-to-left shunt

7. Regarding CO2 kinetics, which of the following is/are true?

a) total amount of CO2 produced is equivalent to the total amount of O2 consumed

b) the a-v difference of CO2 is the same as O2

c) end-tidal CO2 is the same as paCO2

d) all of the above

CO2 metabolism

8. Which of the following is/are associated with increased dead space ventilation?

a) low CO

b) ARDS

c) PE

d) PHTN

e) all of the above

9. With regards to ventilatory mechanics, which of the following statements is/are true?

a) WOB consume 2% of total body O2 consumption

b) WOB may increase to 50% in the postop patient

c) the increased WOB in COPD is due primarily to an increased inspiratory effort

d) airway pressure reflects the compliance of the chest wall and diaphragm as well as the lungs

e) C = V / P

Compliance & Resistance

10. Which of the following indicates the need for immediate ventilatory support?

a) RR > 35bpm

b) paCO2 >60mmHg

c) A-a O2 gradient > 350mmHg

d) VD/VT >0.6

e) shunt fraction greater than 5%

11. ARDS is characterized by:

a) bilateral pulmonary infiltrates

b) paO2/FiO2 <300mmHg

c) PCWP >18mmHg

d) hypoxemia with hypercarbia

e) increased dead space ventilation and increased lung compliance

12. Which of the following treatment are appropriate for the ARDS patient?

a) MV

b) albumin and Lasix

c) PEEP

d) ECMO

e) routine steroids

13. With regards to FRC, which of the following is/are true?

a) FRC = RV + TV

b) atelectasis occurs when the FRC falls below the closing volume (CV)

c) FRC = ERV + RV

d) FRC is increased by PEEP

PFTs

14. Which of the following may be seen with shock?

a) hyperglycemia

b) negative nitrogen balance

c) lactic acidosis

d) metabolic alkalosis

e) hyperkalemia

15. 24yo female undergoes ex lap for a Class IV hemorrhage and is transfused >12U PRBCs. Which of the following is most appropriate?

a) CaCl

b) FFP

c) plt

d) correction of hypothermia

e) heparin

Questions?