ASSESSMENT OF THE PATIENT WITH A LOW BLOOD

PRESSURE

Peter E. Morris, MD, FACP, FCCPPulmonary & Critical Care Medicine

Wake Forest University School of MedicineWinston Salem, NC

ASSESSMENT OF THE PATIENT WITH A LOW BLOOD PRESSURE

What is an abnormal blood pressure?

HYPOVOLEMIA

HYPOTENSION

SHOCK

ADEQUATE PERFUSION

BLOOD PRESSURE GOAL

MAP vs Systolic?

MAP = 60-70 mmHg

Systolic = >90

CEREBRAL PERFUSION PRESSURE (CPP)

MAP-ICP = CPP

•65-5 = 60 mmHG

•<60 risk of brain ischemia •and neuronal damage

Normal HypertensiveRelative

CBF

(Autoregulation)

50 100 150 200

MAP

SHOCK

• Cardiogenic

• Neurologic

• Distributive

• Hypovolemic

SHOCK

• Preshock —known as warm shock or compensated shock

• homeostatic mechanisms rapidly compensate for diminished perfusion

• Despite a 10 percent reduction in total effective blood volume, a previously healthy adult may be asymptomatic

• Tachycardia, peripheral vasoconstriction, modest decrement in systemic blood pressure

SHOCK

• Shock — During this stage, regulatory mechanisms are overwhelmed - signs and symptoms of organ dysfunction appear: tachycardia, tachypnea, metabolic acidosis, oliguria, cool and clammy skin.

• A 20 to 25 percent reduction in effective blood volume

REASONS FOR SHOCK

•Hemorrhage

•Myocardial dysfunction (cardiomyopathy, ischemia, pharmacologic, toxic,

valvular)

•Circulatory obstruction (pulmonary embolus, cardiac tamponade, pneumothorax)(cont’d)

•Hypovolemia (gastrointestinal [GI], insensible losses)

•Central sympathetic disruption (Drug overdose)

•Arteriovenous fistula (cont’d)

REASONS FOR SHOCK

Vascular Endothelial Cell Dysfunction/Disruption

•Sepsis (bacterial, viral, fungal)

•Anaphylaxis

•Dyshemoglobinemia (carbon monoxide, methemoglobinemia)

•Cellular poisons (cyanide sulfur, iron, lithium)

•Traumatic or massive tissue destruction

•Heat shock, Hypothermia

REASONS FOR SHOCK

Compensatory reflexes may be more prominently demonstrated in young adults.

Considerable variability exists at extremes of age

Most notably, younger individuals are able to maintain normal blood pressure until cardiovascular decompensation is imminent

Age Variation

FOR MOST** ACUTELY HYPOTENSIVE PTS:

ifPULMONARY EDEMA (-)

then

FLUID CHALLENGE IS AN APPROPRIATE FIRST RESPONSE

FLUID CHALLENGE?

BOLUS OF FLUID?

1. HOW MUCH?

2. HOW FAST?

3. LENGTH OF TUBING

4. DIAMETER OF CATHETER

5. LENGTH OF CATHETER

6. PRESSURE BAGS

LOW URINE OUTPUT

DEHYDRATION

INTRAVASCULAR VOLUME

HYPOTENSION

A Spectrum of Severity

DURING RESUSCITATION

REMEMBER TO MONITOR:

MENTAL STATUS

VITAL SIGNS (MAP - O2 SATS)

URINE OUTPUT

SKIN PERFUSION

(LACTATE)

SHOCK RESUSCITATION• Golden Rule – early 1960s

Parkland Hospital, Dallas TX First hour post-trauma – attention to blood pressure improves outcome

• Traditionally, Internal Medicine-trained critical care practitioners:– Never heard of Golden Rule?– Fear of Volume resuscitation? 2o Fear of CHF or

Intubation?

04/11/23 18

Sepsis: Defining a Disease Continuum

SIRS– Temperature 38oC or

36oC– HR 90 beats/min– Respirations 20/min– WBC count

12,000/mm3 or 4,000/mm3 or >10% immature neutrophils

SepsisSepsisInfectionInfection Severe SepsisSevere Sepsis

• Sepsis with 1 sign of organ failure

– Cardiovascular (refractory hypotension)

– Renal– Respiratory– Hepatic– Hematologic– CNS– Unexplained metabolic

acidosis

Shock

Mechanical Ventilation

Acute Dialysis

Early Goal-Directed Therapy for Septic Shock

• Randomized, non-blinded trial of traditional vs early goal-directed therapy (EGT)– Septic shock

unresponsive to 20 mL/kg crystalloids, or

– Lactate 4 mmol/L

• Standard– CVP 8-12 mm Hg

– Vasopressors for SBP 90 mm Hg

– Maintain UOP 0.5 mL/kg/hr

– MAP 65 mm Hg

• Goal-directed– Above, plus

– Patients monitored with CVP and SVO2

– If SVO2 <70%• RBCs until Hct 30%

• If SVO2 still <70%, add dobutamine to dose of 20 μg/kg/min

Rivers E, et al. N Engl J Med 2001;345:1368-77.

O2 Delivery & Uptake during Severe Sepsis

• D-O2 = Cardiac Output x Hgb x O2 sat• V-O2 = Body’s uptake of oxygen

• As blood circulates from arteries – capillaries – veins: oxygen content decreases

• Response to increase tissue demand (exercise, illness) = cardiac output, O2 extraction

O2 Delivery & Uptake during Severe Sepsis

• Crude estimate of O2 extraction is Arterial O2 sat minus Venous O2 sat

• Normal arterial O2 sat = > 95%Normal mixed venous O2 sat = 75%

• For Severe Sepsis Pt in shock:if mixed venous O2 sat = 50%, suspicion that tissue O2 needs may not be met

Arterial Hemoglobin-O2 saturation

Nl = 95%

O2 content high

Mixed venous hemoglobin-O2 saturation (SVO2)

Nl = 70-75%

O2 content low

Arterial Hemoglobin-O2 saturation

Nl = 95%

O2 content high

Mixed venous hemoglobin-O2 saturation (SVO2)

<70%

O2 content very low

Flow-dependent O2 Uptake

0%

25%

50%

75%

RBCs Dobutamine

Traditional

EGT

EGT Pts Received More Fluids, RBCs and Dobutamine

Rivers E, et al. N Engl J Med 2001;345:1368-77.

Pressors

Fluids in mL

First 6 hours0

1000

6000

2000

3000

4000

5000

Patients Receiving Treatment (%)

0

10

20

30

40

50

60

In-hospitalmortality (all

patients)

28-day mortality 60-day mortality

Standard Therapy EGT

Early Goal-Directed Therapy for Septic Shock

• EGT* in patients with severe sepsis produced the following:– 42% in relative risk of

in-hospital and 28-day mortality (P=0.009, P=0.01)

– 33% in relative risk of death at 60 days (P=0.03)

• NNT to prevent 1 event (death) = 6-8

*Aggressive resuscitation begun in emergency department.Rivers E, et al. N Engl J Med 2001;345:1368-77.

Mo

rtal

ity

(%)

Surviving Sepsis Campaign guidelines for management of

severe sepsis and septic shock• Sponsoring Organizations: American Association of Critical-Care Nurses,

American College of Chest Physicians, American College of Emergency Physicians, American Thoracic Society, Australian and New Zealand Intensive Care Society, European Society of Clinical Microbiology and Infectious Diseases, European Society of Intensive Care Medicine, European Respiratory Society, International Sepsis Forum, Society of Critical Care Medicine, Surgical Infection Society,

• Crit Care Med 2004; 32:858–873

6 & 24 Hour Severe Sepsis BUNDLES

• 6 Hour:– Dx– Lactate– Antibiotics– Fluids– CVP– MAP>65– mvO2 sat

• 24 Hour:– Glc<150– Vent Plat Press<30– APC considered– Adrenal Evaluation

NUMBER OF ADMISSIONS November & December vs. March Group # Admissions November 110 December 108

218

March 130 130

Number of patients with Severe Sepsis Group # Severe

Sepsis

November 27 December 25

March 45

HOURLY BLOOD PRESSURES – MAP – Severe Sepsis Patients Median

(range) Mean (std dev)

November & December (n = 50)

61.72 (46.89 – 110.33)

65.82 (12.96)

March (n = 44) 67.11 (47.58 – 110.61)

71.08 (14.39)

P = 0.0508

Non-order (n=30)

65.94 (47.58 – 110.61)

70.46 (14.55)

Order (n=14) 68.72 (57.22 – 108.0)

72.40 (14.48)

p = 0.6361*

MAP

60

65

70

75

80

85

1 2 3 4 5 6

HOUR

MA

P

NOV/DEC MARCH-NO ORDER MARCH - ORDER

HOURLY VOLUME OF RESUSCITATION FLUID – Severe Sepsis Patients

Median (range)Mean (std dev)

November & December (n = 50)

424.58 (0 – 3489.50)

604.03 (626.25)

P = 0.6889*

March (n=44) 452.42 (1.67 – 1588.33)

569.71 (442.48)

Non-order (n=30) 403.33 (1.67 – 1498.33)

444.87 (400.96)

P = 0.0014**

Order (n=14) 770.58 (130.0 – 1588.3)

837.23 (491.45)

*no difference in average volume between Nov/Dec & March**significant difference in average volume between order andnon-order March sepsis patientsNote: t-test done on log volume

ORDER SHEET USAGE AND ADMISSION SOURCE 14 of 45 (31.11%) of the March Severe Sepsis patients had the Order Sheet Order Sheet =

No Order Sheet = Yes

Emergency 15 (53.57%) 13 (46.43%) WFUBMC Clinic

1 (100%) 0

Outside Hospital

11 1

Outside Emergency

0 0

Other 2 0 29 (67.44%) 14 (32.56%)

Chart Copy

NORTH CAROLINA BAPTIST HOSPITAL PHYSICIAN ORDER FORM PHYSICIANS: All orders should be written generically and using the Metric System; include the physician's signature, PRINTED name, ID Number, beeper number and the date/time. A generically and therapeutically alternative drug as approved by the P & T Committee may be dispensed unless the order is specifically designated "Dispense as Written"." Form Approved by Medical Record Informatics Technology Committee: 02/05

FAX

TITLE: SEVERE SEPSIS ORDER SET – ICU (ADULT) Page 1 of 4 Consider for use with suspicion of infection and at least one organ dysfunction

DATE

TIME

(PLEASE CIRCLE OR CHECK APPROPRIATE ORDERS AND FILL IN BLANKS AS NEEDED)

DIAGNOSIS: ALLERGIES:

GOALS OF THERAPY Severe Sepsis 6 Hour Bundle - starts with timing of first organ dysfunction

(Refer to Page 5 of Sepsis Bundle Algorithm for organ dysfunction definitions) MAP>65 mmHg CVP >8 mmHg

Urine Output >0.5 cc/kg/hour Central venous oxygen saturation 70-80%

Antibiotics initiated within 1 hour

1. Admit to ICU- see separate MICU admission orders

2. Baseline Labs- STAT (if not already done in the Emergency Department or on the Floor) CBC with diff CMP ABG with lactate PT/PTT Random Serum Cortisol Level Type and Screen 3. Line Placement- Consider (if not already done in the Emergency Department or the Floor) Triple lumen central venous catheter (subclavian or internal jugular) Continous central venous oxygen saturation triple lumen catheter (PreSep catheter) Foley catheter with hourly urine meter bag Thermister Foley

4. Cultures (if not already done in the Emergency Department or on the Floor) Urinalysis and Culture Blood Cultures X 2 (if central line present, may draw one from central line, one peripheral) Sputum Culture and Gram Stain Other: CSF Pleural Fluid Peritoneal Fluid Wound Stool Other: _________ DATE: TIME:

Physician Computer ID #

Physician SIGNATURE:

PRINT Physician NAME:

Beeper #:

Chart Copy

NORTH CAROLINA BAPTIST HOSPITAL PHYSICIAN ORDER FORM PHYSICIANS: All orders should be written generically and using the Metric System; include the physician's signature, PRINTED name, ID Number, beeper number and the date/time. A generically and therapeutically alternative drug as approved by the P & T Committee may be dispensed unless the order is specifically designated "Dispense as Written"." Form Approved by Medical Record Informatics Technology Committee: 02/05

FAX

TITLE: SEVERE SEPSIS ORDER SET – ICU (ADULT) Page 1 of 4 Consider for use with suspicion of infection and at least one organ dysfunction

DATE

TIME

(PLEASE CIRCLE OR CHECK APPROPRIATE ORDERS AND FILL IN BLANKS AS NEEDED)

DIAGNOSIS: ALLERGIES:

GOALS OF THERAPY Severe Sepsis 6 Hour Bundle - starts with timing of first organ dysfunction

(Refer to Page 5 of Sepsis Bundle Algorithm for organ dysfunction definitions) MAP>65 mmHg CVP >8 mmHg

Urine Output >0.5 cc/kg/hour Central venous oxygen saturation 70-80%

Antibiotics initiated within 1 hour

1. Admit to ICU- see separate MICU admission orders

2. Baseline Labs- STAT (if not already done in the Emergency Department or on the Floor) CBC with diff CMP ABG with lactate PT/PTT Random Serum Cortisol Level Type and Screen 3. Line Placement- Consider (if not already done in the Emergency Department or the Floor) Triple lumen central venous catheter (subclavian or internal jugular) Continous central venous oxygen saturation triple lumen catheter (PreSep catheter) Foley catheter with hourly urine meter bag Thermister Foley

4. Cultures (if not already done in the Emergency Department or on the Floor) Urinalysis and Culture Blood Cultures X 2 (if central line present, may draw one from central line, one peripheral) Sputum Culture and Gram Stain Other: CSF Pleural Fluid Peritoneal Fluid Wound Stool Other: _________ DATE: TIME:

Physician Computer ID #

Physician SIGNATURE:

PRINT Physician NAME:

Beeper #: