Download Surgical Intensive Care

Surgical Intensive Care
JUNYI LI, MD
Board certified in Anesthesiology
Board certified in Critical Care Medicine
Board certified in Transesophageal
Echocardiography
March 31, 2009
lijunyiutmb@yahoo.com
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Subspecialty ICU
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Medical Intensive Care Unit (MICU)
Coronary Care Unit (CCU)
Surgical Intensive Care Unit (SICU)
Neurological Intensive Care Unit (NICU)
Cardiovascular Intensive Care Unit (CVICU)
Pediatric Intensive Care Unit (PICU)
Neonatal Intensive Care Unit (NICU)
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SICU Admission Criteria
• Preoperative status
Major trauma
Surgical Procedure
Pt’s preexisting disease
• Intraoperative event
Large volume shift
Unexpected surgical complication
Unexpected anesthesia complication
• Postoperative status
Unexpected postop complication
Pt’s status
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Who need to be admitted to SICU ?
• 18 y/o health male presented for right inguinal hernia repair
under spinal anesthesia and uneventful intraop and postop.
• 50 y/o female with controlled HTN and DM for lumbar
laminectomy under general anesthesia with EBL 500 ml.
• 75 y/o male with stable angina, COPD required home oxygen
for TURP under spinal anesthesia
• 60 y/o male presented for AAA repair
• 54 y/o female with esophageal cancer presented for
esophagectomy
• 95 y/o female presented for right hip arthroplasty
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SICU Management
• Respiratory care
• Hemodynamic monitoring and management
Noninvasive
Invasive
• Infection in SICU
• Acid-base disorders
• Fluid and electrolyte disorders
• Blood component therapy
• Nutrition support
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Respiratory care – basic monitor
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Respiratory rate
Chest movement
Breath sound
Color
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Respiratory care – lung volume
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Tidal volume (VT)
Minute ventilation (Vm)
Functional residual capacity (FRC)
Vital capacity (VC)
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Respiratory care - ventilation
• Ventilation-perfusion (V/Q) ratio:
normal V/Q=4L/5L=0.8
• Dead space ventilation: V/Q>1
anatomic dead space & physiologic dead space
• Intrapulmonary shunt: V/Q<0.8
true shunt (V/Q=0) and venous admixture
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V/Q relationship and associated blood gas
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Effect of shunt fraction on PAO2
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Effect of shunt fraction on PAO2 and PACO2
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Ventilation-perfusion
Quantitative determinations
• Dead space (Vd/Vt) = (PACO2 – PECO2)/PACO2
• Shunt fraction (Qs/Qt) =
(CCO2 – CAO2)/(CCO2 –CVO2)
• A-a gradient (PAO2 – PaO2)
PAO2 = PIO2 – (Paco2/RQ)
PAO2 = FIO2(PB –PH2O) – (PaCO2/RQ)
PAO2 = 0.21(760 – 47) – (40 /0.8) = 100 mmHg
• PAO2/FIO2<200, Qs/Qt>20%
PAO2/FIO2>200, Qs/Qt<20%
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Hypoxemia
Disorder
A-a PO2
Hypoventilation
Normal
Pulmonary disorder Increased
DO2/VO2 imbalance Increased
PVO2
Normal
Normal
Decreased
DO2/VO2 – oxygen deliver and uptake ratio
A-a PO2 – PO2 difference between alveolar gas and arterial blood
PVO2 – Mixed venous PO2
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Evaluation of hypoxemia
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Hypercapnia
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Hypercapnia is PACO2>45 mm Hg, due to
Increased CO2 production
Hypoventilation
Increased dead space ventilation
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Evaluation of hypercapnia
High
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Oximetry
• Oximetry detects arterial blood HbO2 and Hb
ratio
• Ear oximetry
• Pulse oximetry
• Co-Oximeters can detect Met Hb and CO Hb
• Mixed venous oximetry measured O2 sat in PA
blood
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CO2 detector and capnometry
• CO2 detector is a method for determining the
success or failure of ET intubation.
• Clinical application of capnometry in ICU:
- Cardiac output monitor
- Ventilator-related mishap detection
- Early detection of nosocomial disorders
- Ventilator weaning
- Controlled hyperventilation
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Acute respiratory distress syndrome
(ARDS)
• A leading cause of acute respiratory failure
with high mortality
• A diffuse inflammatory injury in the lung
• Not an accumulation of watery edema fluid
• Not a primary disease, but a complication
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Common conditions that predispose to ARDS
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ARDS microscopic changes and CXR
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Diagnostic criteria for ALI and ARDS
• Acute onset
• Presence of predisposing condition
• PaO2/FiO2 < 200 mm Hg for ARDS,
< 300 mm Hg for ALI
• CXR – bilateral infiltrates
• PAOP < 18 mm Hg or no clinical evidence of
high LA pressure
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Management of ARDS
• No real treatment for ARDS, only supportive
• Mechanical ventilation:
low-volume ventilation
permissive hypercapnia
positive end-expiratory pressure
• Fluid management – reducing extravascular
lung water
• Pharmacotherapy – uncertain effect
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Respiratory therapy
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Oxygen inhalation therapy
Chest physical therapy
Respiratory pharmacotherapy
Mechanical ventilation
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Oxygen inhalation therapy
• Arterial hypoxemia:
PaO2 < 60 mm Hg (SaO2 < 90 %)
• Tissue hypoxia:
blood lactate > 4 mmHg
• Endpoint of O2 therapy is tissue oxygenation
• Tissue hypoxia may not consistent with arterial
hypoxemia
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Effect of Oxygen on blood flow
• Oxygen tends to reduce systemic blood flow
due to:
1. vasoconstrction in all vascular bed except
the pulmonary circulation
2. decrease in cardiac output
3. negative inotropic effect
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Method of oxygen inhalation
• Low-flow oxygen delivery system with
variable FiO2
• High-flow oxygen delivery system with
constant FiO2
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Low-flow oxygen delivery systems
Device
Reservoir
capacity
Nasal cannula
50 ml
Oxygen face mask
Mask-reservoir bag
Partial rebreather
Nonrebreather
150-250 ml
750-1250 ml
Oxygen flow
(L/min)
FiO2
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5
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5-10
0.21-0.24
0.24-0.28
0.28-0.34
0.34-0.38
0.38-0.42
0.42-0.46
0.40-0.60
5-7
5-10
0.35-0.75
0.40-1.0
FiO2 = 20 + 4 X oxygen flow (L/ml)
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Respiratory pharmacotherapy
• Bronchodilators
• Corticosteroids
• Mucokinetic therapy
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Mechanical Ventilation
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Mechanical ventilation
• Mechanical ventilation is positive pressure
ventilation
• Indications of mechanical ventilation
Rate
ABG: hypoxia and hypercapnia
Mechanical parameter: MV, VC and NIP
Dead space and shunt
• Contraindication of mechanical ventilation
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Effect of positive pressure ventilation
Normal lung
Noncompliant lung
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Effect of positive pressure ventilation
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Respiratory parameter
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Rate: 10 – 20/min
VT: 6 – 10/kg
FiO2: 40 – 100%
PEEP: 5 – 10 cm H2O
PS: 5 – 10 cm H2O
I:E ratio: 1:2
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Patterns of mechanical ventilation
• Control mode ventilation
• Assist-control ventilation
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Pattern of mechanical ventilation
• Volume-controlled ventilation
ACV (assist control ventilation)
IMV (intermittent mandatory ventilation)
SIMV (synchronized IMV)
• Pressure-controlled ventilation
• Pressure support ventilation
• Special pattern:
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Functional mode of ventilator
• PEEP (positive end expiratory pressure)
• PS (pressure support)
• I:E reversal ratio
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Ventilatory mode of mechanical ventilation
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Volume-controlled ventilation
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Pressure-controlled & Pressure support
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PEEP and CPAP
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Effect of PEEP on arterial oxygenation and CI
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Discontinuing mechanical ventilation
• Ventilator required for brainstem respiratory
depression (e.g.,GA in OR or drug overdose) is
easy to discontinue
• Ventilator required for cardiopulmonary
insufficiency is weaning in gradual process
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Discontinuing mechanical ventilation
Clinical evaluation:
Awake
Spontaneous breathing
Ability of airway protection
Stable hemodynamics
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Discontinuing mechanical ventilation
Sequence of weaning:
FiO2 to 50% or less
PEEP to 5 cm H2O or less
PS to 10 cm H2O or less
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Discontinuing mechanical ventilation
Bedside weaning parameters:
Parameter Normal range Threshold for weaning
PaO2/FiO2
VT
Rate
VC
VE
Pi max
Rate/VT
>400
5-7 ml/kg
10-20/min
65-75 ml/kg
5-7 L/min
>-90 cm H2O (F)
>-120 cm H2O (M)
<50/min/L
200
5 ml/kg
<40/min
10 ml/kg
<10 L/min
-24 cm H2O
<100/min/L
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Predictive value of selected weaning parameters
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Discontinuing mechanical ventilation
Methods of weaning:
T-piece weaning
IMV weaning
CPAP weaning
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Diagram of T-shaped circuit
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Hemodynamic monitoring
Noninvasive
• ECG: heart rate, rhythm, ischemia (ST-T)
• Noninvasive BP
• Echocardiography: TTE, TEE, color-doppler
Contractility
Volume status
EF
Ischemia (RWMA)
• Noninvasive cardiac output (through A-line)
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Hemodynamic monitoring
Invasive
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Arterial blood pressure
Central venous pressure
Pulmonary artery catheter and wedge pressure
Cardiac output
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Invasive arterial blood pressure
Indication
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Major CV surgery
Surgery with great hemodynamic change
Surgery with large volume shift and bleeding
Shock and other critical ill patients
Surgery requiring hemodilution and control
hypotension
• Frequent ABG
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Invasive arterial blood pressure
• Contraindication:
only relative contraindication except for
puncture site infection
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Invasive arterial blood pressure
Selection of artery for cannulation
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Radial artery
Ulnar artery
Brachial artery
Femoral artery
Dorsalis pedis and posterior tibial arteries
Axillary artery
Carotid artery – do not use
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Invasive arterial blood pressure
Complication
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Bleeding and hematoma
Vasospam
Thrombosis and thrombi
Aneurysm
Infection
Nerve damage
Necrosis of skin overlying the catheter
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Invasive arterial blood pressure
Waveform
SBP gradually increases
MBP remains unchanged
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Invasive arterial blood pressure
Waveform distortion
Normal test
underdamped
overdamped
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Central venous pressure
Indication
• Fluid administration for severe hypovolemia
and shock
• Infusion of cardiac drugs
• Aspiration of air emboli in craniotomy
• Insertion of transcutaneous pacing leads
• Total parenteral nutrition (TPN)
• Venous access for patients with poor
peripheral veins
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Central venous pressure
Contraindication
• Renal cell Ca extension into RA, RA myxoma,
or fungating tricuspid valve vegetations
• Skin infection at cannulation site
• Severe coagulopathy
• Ipsilateral carotid endarterectomy (IJ),
pneumothorax and hemothorax are relative
contraindication
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Central venous pressure
Selective sites of cannulation
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Internal jugular veins
Subclavian veins
Femoral veins
External veins
Basilic veins
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Central venous pressure
Measurement
• Catheter’s tip lies above or the junction of SVC
and RA
• CVP is measured with cm H2O
• CVP should be measured during end expiration
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Central venous pressure
Waveform
• a wave – atrial contraction, absent in A fib and
exaggearted in JR (cannon wave)
• c wave – TV elevation@early ventricular contraction
• v wave – venous return against to closed TV
• x descent – downward displacement of TV (systole)
• y descent – TV opening during diastole
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Central venous pressure
Complication
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Bleeding and hemotoma
Pneumothorax and hemothorax
Pleural effusion and chylothorax
Line-related infection
Air thrombi
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Pulmonary artery catheterization
Length 110 cm
OD 2.3 mm
Distal port
Proximal port
Balloon at tip
Themistor
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“It Is Time To Pull The PAC”
PAC dose not improve outcome
in critically ill patients
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Background
• Pulmonary artery catheter(PAC) has been used in
critical care practice for three decades
• Majority of PAC are inserted to aid in
management of critically ill pts in ICU and high
risk surgical pts in OR
• Observational studies & small randomized
controlled trials (RCT) showed variable results:
Worse outcome
No difference in outcome
Some benefit
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Summary
• PAC-directed management in high risk
surgical, severe sepsis, shock and RADS
pts is a safe procedure
• PAC use dose not improve outcome
• PAC use may not increase cost of care
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Pulmonary artery catheterization
Indication
• Cardiac disease: CAD with LV dysfunction, valvular
heart disease, heart failure
• Pulmonary disease: ARDS, severe COPD, Pulmonary
hypertension
• Complex fluid management: shock, acute burn ARF,
MOF
• Specific surgical procedure: aortic cross clamp
pheochromocytoma, liver transplants,
• Hemodynamic unstability required cardiovascular
drug therapy
• High-risk obstetrics: severe toxemia
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Pulmonary artery catheterization
Contraindication
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Severe TV or PV stenosis
RA or RV tumor
Endocarditis with vegetation on TV or PV
Other contraindication related to central
venous cannulation
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Pulmonary artery catheter
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Pulmonary artery catheterization
Insertion of catheter
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PCWP and CVP
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Pulmonary artery catheter in chest x-ray
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Pulmonary artery catheterization
Complication
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Complication associated with CV cannulation
Bacteremia and endocarditis
Thrombogenesis and pulmonary infarction
Pulmonary artery rupture and hemorrhage
Arrhythmias and conduction abnormalities
Pulmonary valve damage
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Pulmonary capillary wedge pressure
CVP = RAP = RVEDP
PCWP = LAP = LVEDP
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Hemodynamic parameter
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BSA = (Ht + Wt – 60)/100, nl 1.6 to 1.9 m2
CO = HR x SV
CI = CO/BSA
DO2 = CI x 13.4 x Hb x SaO2
VO2 = CI x 13.4 x Hb x (SaO2 – SvO2)
* SvO2 obtained from PAC distal port
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Hemodynamic Profiles
• Heart failure:
Right heart failure
Left heart failure
High RAP
Low CI
High PVRI
High PCWP
Low CI
High SVRI
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Hemodynamic profiles
• Hypotension:
Hypovolemic
Low CVP
Low CI
High SVRI
Cardiogenic
High CVP
Low CI
High SVRI
Vasogenic
Low CVP
High CI
Low SVRI
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Cardiac output monitoring
• Thermodilution methods
Pulmonary artery catheter
Peripheral artery catheter (Picco)
• Dye dilution methods
• Echocardiography
• Thoracic bioimpedance
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Cardiac output monitoring
Fick principle
CO =
=
Oxygen consumption
a – v O2 content difference
VO2
CaO2 – CvO2
Fick principle is the basis of all indicator
dilution methods of determining cardiac
output
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Thermodilution method
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Hemodynamic management
• Preload
• Afterload
• Cardiac contractility
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Hemodynamic management
Preload
• Monitoring via CVP or PCWP
• Increased preload by giving volume
• Decreased preload by giving diuretics and/or
vasodilators (nitroglycerin)
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Hemodynamic management
Afterload
• Vascular resistance
• Balance between cardiac work and organ
perfusion
• Vasodilators:
Systemic vasodilators: nitroprusside,
calcium channel blockers, a1-blockers
Pulmonary vasodilators: PGE1, PGI, NO
• Vasocontrictors: levophed, epinephrine,
vasopresin
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Hemodynamic management
Inotropic agents
• Positive inotropic agents: epinephrine,
dopamine, dobutamine, PDEI (milrinone)
• Negative inotropic agents: beta blocker and
calcium channel blockers
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Hemodynamic management
Mechanical support (IABP)
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Hemodynamic effect of IABP
• Decrease afterload and promote SV
• Increased diastolic pressure and coronary
blood flow in hypotensive patients
• Indication: AMI, cardiac shock, unstable
angina, acute MR
• Contraindication: AI, aortic dissection and
aortic graft in thoracic aorta
• Complication: leg ischemia, septicemia
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Acute renal failure (ARF)
• The hallmark of ARF is azotemia and oliguria
• Lab: blood urea nitrogen(BUN), criatinine(Cr), blood
electrolytes, glumerular filtration rate
• Etiology: prerenal, renal and postrenal
Renal ischemia (50%),
Nephrotoxines (35%),
Intrinsic renal disease (15%)
50% of ARF in SICU due to major trauma or surgery
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Etiology of ARF
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Treatment of ARF
• Supportive management
• Diuretics and mannitol to maintain urine
output in nonoliguric patients
• Renal dose dopamine?
• Glucocorticoids for ARF due to vasculitis or
glomerulonephritis
• Other: restrict fluid, sodium, potassium, posph
• Renal replacement therapy (dialysis)
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Renal Replacement Therapy
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Infection in SICU
• Infections are leading cause of death in ICUs
• Community acquired and hospital acquired infection
• Strains of bacteria resistant to commonly used
antibiotics are common
• Advanced age, prolonged use of invasive devices,
respiratory failure, renal failure and head trauma are
established risk factors for hospital acquired infection
• Multiple antibiotics and broad spectrum antibiotics
are commonly used in SICU
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Nutrition support in SICU
• Maintaining adequate nutrition in critically ill
patients improves wound healing. Restore
immune competence and reduces morbidity
and mortality
• Critically ill patients generally required 1.01.5g/kg/day instead of 0.5g/kg/day for
nonstressed patients
• Enteral nutrition and parenteral nutrition
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Enteral Nutrition in SICU
• GI tract is the route of choice for nutrition
support when its functional integrity is intact
• Enteral nutrition is simpler, cheaper, less
complicated, and fewer complication
• Enteral nutrition can better preserve GI
structure and function
• Diarrhea is most common problem related to
hyperosmolarity of the solution or lactose
intolerance
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Parenteral Nutrition in SICU
• Total parenteral nutrition (TPN) is indicated if
the GI tract cannot be used of if absorption is
inadequate
• Complications of TPN are catheter-related and
metabolic
• The most common problem in TPN is
hyperglycermia
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