Shock. Undifferentiated Shock: Beyond Blood Pressure. Shock. Epidemiology. Matthew Strehlow, MD Stanford University

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1 Shock Undifferentiated Shock: Beyond Blood Pressure Matthew Strehlow, MD Stanford University Shock Shock - The rude unhinging of the machinery of life -SD Gross 1872 Epidemiology Shock - inadequate tissue perfusion Cryptic Shock - inadequate tissue perfusion without hypotension 1 million patients with shock will present to US EDs each year Up to 50% mortality rate Majority of patients in ICUs with shock were initially seen in the ED

2 Outline Outline Early vs delayed recognition of shock Recognizing shock How vital are vital signs? Early vs delayed recognition of Shock Detecting cryptic shock The role of ultrasound in overt shock Annane et al. Lancet 2007 Annane et al. Lancet 2007

3 Sprung et al. NEJM 2008 Sprung et al. NEJM 2008 Sprung et al. NEJM 2008 Sprung et al. NEJM 2008

4 Early Recognition Sebat et al. Crit Care Med Nov 2007 Interventions 72 hours Educational program Rapid recognition and response system Protocolized approach to care Sprung et al. NEJM 2008 Early Recognition Early Interventions Sebat et al. Crit Care Med Nov 2007 Results Time to interventions predicted mortality Mortality rate decreased 40% to 12% Traumatic shock Golden hour Cardiogenic shock Early fibrinolysis or catheterization Septic shock Early goal-directed therapy Early antibiotics

5 Delayed Interventions Cardiogenic shock Vasopressors Inotropes Septic shock ICU based goal-directed therapy Steroids Early recognition of shock is the most critical feature in saving patients lives! Case 1 Recognizing Shock 35 yo male motorcycle driver in a solo MVC Initial EMS vital signs: HR 80, BP 85/50 Initial ED vital signs: HR 90, BP 120/70

6 Case 1 Low BP in the Field 35 yo male motorcycle driver in a solo MVC Initial EMS vital signs: HR 80, BP 85/50 Initial ED vital signs: HR 90, BP 120/70 Lipsky et al. J Trauma Nov year prospective observational study 1028 patients normotensive in the ED 71 (7%) were hypotensive in the field Are this patient s initial VS in the field concerning? Low BP in the Field Emergency therapeutic operation Within 6 hours of ED arrival Determined emergent and therapeutic by 2 out of 3 surgeons reviewing the cases Mortality 40% 30% 20% 10% 0% Low BP in the Field: Increased Injury Rate of Emergency Therapeutic Operation 11% 37% Normotensive Hypotensive OR = 4.5 (95%CI= )

7 Low BP in the Field: Increased Mortality Hypotension is a Late Finding of Injury 8% Mortality Rate Median SBP vs Mortality 6% 6% Median % 2% 3% SBP % Normotensive Hypotensive OR = 2.3 (95%CI= ) % 20% 40% 60% 80% Mortality 65% Parks et. al, Am J Surg 2006 Mortality Increases if SBP < 110 Mortality increased 4.8% for every 10 mmhg drop below 110 mmhg Mortality Increases if SBP < 110 Mortality increased 4.8% for every 10 mmhg drop below 110 mmhg *Severe head injury patients excluded *Severe head injury patients excluded Eastridge et. al, J of Trauma 2007 Eastridge et. al, J of Trauma 2007

8 ATLS Guidelines for Estimated Blood Loss ATLS Guidelines for Estimated Blood Loss Blood Loss Class 1 <0.75L Class L Class L Class 4 >2L Blood Loss Class 1 <0.75L Class L Class L Class 4 >2L HR <100 >100 >120 >140 HR <100 >100 >120 >140 BP Normal Normal Low Low BP Normal Normal Low Low ATLS Manual 7th ed. ATLS Manual 7th ed. Heart Rate: Is it truly vital? Heart Rate is Not Predictive of Outcomes Brasel et al. J Trauma April 2007 Retrospective review at a single hospital 10,825 patients Evaluated for emergency intervention early transfusion high Injury Severity Score (>25) Brasel et. al, J. of Trauma 2007

9 Heart Rate is Not Predictive of Outcomes Heart Rate is Not Predictive of Outcomes Brasel et. al, J. of Trauma 2007 Brasel et. al, J. of Trauma 2007 Heart Rate is Not Predictive of Bleeding McGee, JAMA March 1999 Systematic review of acute blood loss Significant blood loss (630 ml to 1150 ml) supine tachycardia (HR > 100) sensitivity (95% CI) = 12% (5-24) specificity (95% CI) = 96% (88-99) Vital Signs in Trauma: The Bottom Line A low BP in the field is predictive of injury even if initial ED BP is normal A BP of 90 is a very late finding A normal HR means nothing!!!

10 Case 1: Update Predicting Severity of Injury in Trauma Patients 35 yo male motorcycle driver in a solo MVC Episode of hypotension during transport and improved in ED Can we detect cryptic shock and predict the severity of injury in trauma patients? Base deficit Lactate Sublingual capnometry Others OSI Inc. homepage accessed July 2007 Base Deficit Lactate Also termed negative base excess Base deficit is the amount of acid that must be remove from the body to return the ph to 7.4 Normal -2 to 2 >6 significantly abnormal Marker of oxidative stress (anaerobic metabolism) Rapidly removed by liver Normal level 0.5 to 1.5 meq/l >2 abnormal >4 significantly abnormal (lactic acidosis)

11 Sublingual Capnometry Similar to oral temperature 2 minutes to calibrate Measurement of PCO2 Marker of splanchnic perfusion Normal <45 Significantly abnormal >60 SLCO2, BD, and Lactate Predict Bleeding Blood Loss SLCO2 Base Deficit Lactate None Mild to Moderate Severe OSI Inc. homepage accessed July 2007 Baron et. al, J Trauma 2004 SLCO2, BD, and Lactate Predict Mortality Predictors of Mortality Base deficit ROC (0.87, ) Lactate ROC (0.80, ) SLCO2 ROC (0.82, ) Cryptic Traumatic Shock: The Bottom Line Elevated initial base deficit, lactate +/- SLCO2 Signs of cryptic shock (i.e. bleeding) Predict mortality Baron et al. J of Trauma Jan 2007

12 Case 1 Follow-up 35 yo male motorcycle driver in a solo MVC Episode of hypotension during transport and improved in ED Case 2 67 yo man with altered mental status HR 120, BP 75/45, RR 48, SaO2 96% What is the etiology of his shock? Base deficit 12 Grade IV left kidney laceration OR emergently for nephrectomy Discharged day 10 Differential Diagnosis Question LV failure Hemoperitoneum Severe dehydration Cardiac tamponade Pulmonary embolus Sepsis Aortic dissection Thyrotoxicosis Dysrhythmia Gastrointestinal Bleed Abdominal infection Tension pneumothorax Anaphylaxis Neurogenic shock Valvular dysfunction Medication error or OD ACS Adrenal failure Autonomic dysfunction Mesenteric ischemia Moore et al. Acad Emerg Med 2002 According to the above study how often did ED physicians determine the correct etiology of their patients in shock? 25% 45% 65% 85%

13 Moore et al. Acad Emerg Med 2002 According to the above study how often did ED physicians determine the correct etiology of their patients in shock? 25% 45% 65% 85% Question 25% Organized Diagnostic Approach to Shock Simple Rapid Ideal Diagnostic Test Non-invasive Readily available Reproducible Accurate No side effects Performed in ED Goal-Directed Ultrasound Goal-Directed Ultrasound Pros Cons Pros Cons Non-invasive No side effects Readily available Performed in ED Rapid

14 Goal-Directed Ultrasound Ultrasound for Undifferentiated Shock Pros Non-invasive No side effects Readily available Performed in ED Rapid Cons Accurate? Operator dependent Patient dependent Training required Jones, Crit Care Med hypotensive patients randomized immediate (15 min) vs delayed (30 min) ultrasound Main outcome measures Correct diagnosis Number of diagnoses remaining in differential Jones Protocol: 7 views Jones Protocol: Results 1. Subcostal cardiac 2. Inferior vena cava 3. Parasternal long axis cardiac 4. Apical 4 chamber cardiac 5. Right upper quadrant (RUQ) 6. Pelvic 7. Abdominal aorta Correct diagnosis 80% (early US) vs 50% (delayed US) 30% improvement (95%CI, 16%-42%) Median number of diagnoses in differential 4 (early US) vs 9 (delayed US) (p<0.0001) Mortality 17% (early US) vs 15% (delayed US)

15 Jones Protocol: Challenges 1. Subcostal Cardiac View Average time 5.9 minutes Training program for bedside ultrasound >100 non-cardiac US >25 cardiac US 6 hour didactic lecture and lab Is a pericardial effusion present Yes or No If yes, is tamponade physiology present? Yes or No Liver RV LV RV 2. IVC View LV Subcostal Cardiac View Is there evidence of IVC collapse? Yes or No Collapse is defined as >50% reduction in diameter with inspiration Liver IVC

16 3. Parasternal Long Axis Cardiac View IVC What is the LV function? hyperdynamic normal moderately impaired severely impaired Subcostal Cardiac View RV RV LV Function judged by inspection of wall contraction and thickening during systole 4. Apical 4 Chambered Cardiac View LV What is the RV size? Normal or Dilated Parasternal Long Axis Cardiac View Confirm LV function RV LV

17 RV LV 5. Right Upper Quadrant Is intra-peritoneal fluid present? Yes or No Liver Kidney Apical 4 Chambered Cardiac View Anechoic collection between liver and kidney 6. Pelvic View Is intra-peritoneal fluid present? Yes or No Bladder Right Upper Quadrant Sagittal and transverse planes

18 7. Abdominal Aorta View Is an abdominal aortic aneurysm present? Yes or No Sagittal and transverse planes to the level of bifurcation Pelvic View IVC Aorta Aorta 7. Abdominal Aorta View Is an abdominal aortic aneurysm present? Yes or No Sagittal and transverse planes to the level of bifurcation IVC Aorta Abdominal Aorta View

19 Jones Protocol Summary UHP Ultrasound Protocol 7 views 5.9 minutes to complete Improved diagnostic accuracy in shock Requires training Rose, Am J Emerg Med July 2001 Undifferentiated Hypotensive Patient (UHP) 3 views that maximize time and sensitivity RUQ view (intra-peritoneal fluid) Subcostal view (pericardial fluid) Abdominal aorta (AAA) UHP Protocol Shock and Ultrasound: The Bottom Line Critical tool in ED assessment Improves ED physician diagnostic accuracy Ideal protocol not yet determined

20 Case 2 Follow-up Case 3 67 yo M with AMS and hypotension IV NS and dopamine UHP protocol Pericardial effusion noted Pericardiocentesis performed in ED VS improved Admitted to ICU 70 yo female with fatigue T 97.6, HR 80, BP 85/40, RR 16, 95% RA 1 L NS administered and BP improved (100/45) Does a single low BP reading in the ED have prognostic value? ED Hypotension ED Hypotension Portends Increased Mortality Jones, Chest October 2007 Prospective cohort of 4,790 ED admissions Compared mortality in: Hypotension Sustained Episodic Transient 0% 5% 10% 15% Exposures (SBP <100) None Controls (SBP >100) Mortality Jones, Chest October 2007

21 ED Hypotension Portends Increased Mortality Lowest BP < >99 0% 5% 10% 15% 20% Mortality Case 3: Update The patients BP remains stable but given her increased mortality risk from the transient low BP a further evaluation is conducted CXR - left lower lobe infiltrate Lactate How should we interpret this patient s elevated lactate? Jones, Chest October 2007 Elevated Lactate Predicts Mortality in Sepsis Lactate Marker of cellular hypoxia Higher levels are associated with increased mortality Shapiro N et al Ann Emerg Med 2005;45: Mortality Risk Relative to Lactate Level 30% 24% 18% 12% 6% 0% >4 Lactate Level (mmol/l) Elevated Lactate Predicts Mortality in Sepsis Howell et al. Intensive Care Med Nov 2007 Patients with lactate >4 without septic shock Mortality rate 26.5%

22 = Lactate Clearance Lactate decrease by 10% at 6 hours predicted Increased survival Less vasopressors (Lactate 0hrs - Lactate 6hrs )x100 Lactate 0hrs Effect of Lactate Clearance on 70.0% 52.5% 35.0% Mortality 17.5% 0% Vasopressors Decreasing Not Decreasing Nguyen et al. Crit Care Med 2004;32: Factors That May Elevate Lactate Inadequate Oxygen Delivery Volume depletion or Profound dehydration Significant blood loss Septic shock Profound anemia Severe hypoxemia Prolonged carbon monoxide exposure Trauma Disproportionate Oxygen Demands Hyperthermia Shivering Seizures Strenuous exercise Inadequate Oxygen Utilization Systemic inflammatory response syndrome Diabetes mellitus Total parenternal nutrition Thiamine deficiency HIV infection Drugs such as metformin, salicylate, antiretroviral agents, isoniazid, propofol, cyanide Lactate: The Bottom Line Case 3 Follow-up Elevated lactate portends a worse prognosis in hypotensive and normotensive patients Serial lactates can help monitor response to therapy 70 yo F with pneumonia and elevated lactate Sepsis code activated Early Goal-Directed Therapy initiated Patient is admitted to ICU and within an hour becomes hypotensive requiring multiple vasopressors

23 Summary Summary Vital signs HR and BP are late findings A single low BP increases mortality risk Base deficit and lactate BD predicts mortality/injury in trauma Lactate predicts mortality in septic shock Ultrasound assists in diagnosing the undifferentiated hypotensive patient Special Thanks Sarah Williams, Director of Ultrasound Laleh Gharahbaghian, Ultrasound Fellow Stanford University School of Medicine J. Christian Fox, Director of Ultrasound UC Irvine School of Medicine Defer no time, delays have dangerous ends -William Shakespeare