A 19-year-old man presents to the emergency department after a motor vehicle accident. The patient reports left shoulder pain that worsens with deep inspiration. Medical history is significant for a recent diagnosis of infectious mononucleosis. His temperature is 99°F (37.2°C), blood pressure is 80/55 mmHg, pulse is 115/min, and respiratory rate is 22/min. On physical exam, there is abdominal guarding, abdominal tenderness in the left upper quadrant, and rebound tenderness. The patient’s mucous membranes are dry and skin turgor is reduced. Which of the following most likely represents the acute changes in renal plasma flow (RPF) and glomerular filtration rate (GFR) in this patient?

Decreased RPF and decreased GFR

No change in RPF and decreased GFR

No change in RPF and increased GFR

Decreased RPF and no change in GFR

A 37-year-old man is brought to the emergency department by ambulance after a motor vehicle accident. He suffered multiple deep lacerations and experienced significant blood loss during transport. In the emergency department, his temperature is 98.6°F (37°C), blood pressure is 102/68 mmHg, pulse is 112/min, and respirations are 22/min. His lacerations are sutured and he is given 2 liters of saline by large bore intravenous lines. Which of the following changes will occur in this patient's cardiac physiology due to this intervention?

Increased cardiac output and increased right atrial pressure

Increased cardiac output and unchanged right atrial pressure

Decreased cardiac output and increased right atrial pressure

Increased cardiac output and decreased right atrial pressure

Decreased cardiac output and decreased right atrial pressure

A 35-year-old woman is brought to the emergency department 45 minutes after being rescued from a house fire. On arrival, she appears confused and has shortness of breath. The patient is 165 cm (5 ft 5 in) tall and weighs 55 kg (121 lb); BMI is 20 kg/m2. Her pulse is 125/min, respirations are 29/min, and blood pressure is 105/65 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 97%. Examination shows second and third-degree burns over the anterior surfaces of the chest and abdomen, and the anterior surface of the upper extremities. There is black debris in the mouth and nose. There are coarse breath sounds over the lung bases. Cardiac examination shows no murmurs, rubs, or gallop. Femoral and pedal pulses are palpable bilaterally. Which of the following is the most appropriate fluid regimen for this patient according to the Parkland formula?

Administer 6 liters of intravenous crystalloids over the next 24 hours

Administer 4 liters of intravenous colloids over the next 8 hours

Administer 5 liters of intravenous colloids over the next 6 hours

Administer 5 liters of intravenous crystalloids over the next 6 hours

Administer 8 liters of intravenous colloids over the next 12 hours

A 12-year-old boy is brought to the emergency department after a motor vehicle collision. He was being carpooled to school by an intoxicated driver and was involved in a high velocity head-on collision. The patient is otherwise healthy and has no past medical history. His temperature is 99.2°F (37.3°C), blood pressure is 80/45 mmHg, pulse is 172/min, respirations are 36/min, and oxygen saturation is 100% on room air. A FAST exam demonstrates free fluid in Morrison pouch. The patient’s parents arrive and state that they are Jehovah’s witnesses. They state they will not accept blood products for their son but will allow him to go to the operating room to stop the bleeding. Due to poor understanding and a language barrier, the parents are also refusing IV fluids as they are concerned that this may violate their religion. The child is able to verbalize that he agrees with his parents and does not want any treatment. Which of the following is the best next treatment for this patient?

Blood products and emergency surgery

Observation and monitoring and obtain a translator

IV fluids alone as surgery is too dangerous without blood product stabilization

IV fluids and emergency surgery

IV fluids and vasopressors followed by emergency surgery

An 8-year-old boy is shifted to a post-surgical floor following neck surgery. The surgeon has restricted his oral intake for the next 24 hours. He does not have diarrhea, vomiting, or dehydration. His calculated fluid requirement is 1500 mL/day. However, he receives 2000 mL of intravenous isotonic fluids over 24 hours. Which of the following physiological parameters in the boy’s circulatory system is most likely to be increased?

Interstitial hydrostatic pressure

A 7-year-old boy is brought to the emergency room because of severe, acute diarrhea. He is drowsy with a dull, lethargic appearance. He has sunken eyes, poor skin turgor, and dry oral mucous membranes and tongue. He has a rapid, thready pulse with a systolic blood pressure of 60 mm Hg and his respirations are 33/min. His capillary refill time is 6 sec. He has had no urine output for the past 24 hours. Which of the following is the most appropriate next step in treatment?

Start IV fluid resuscitation with normal saline or Ringer’s lactate, along with monitoring of vitals and urine output

Start IV fluid resuscitation by administering colloid solutions

Provide oral rehydration therapy to correct dehydration

Give initial IV bolus of 2 L of Ringer’s lactate, followed by packed red cells, fresh frozen plasma, and platelets in a ratio of 1:1:1

A 23-year-old woman comes to the office because of a 2-day history of right knee pain. She says, "I can't run anymore because my knee hurts." The pain is localized "somewhere under the kneecap" and is achy, rated 5/10, but increases to 8/10 with prolonged sitting. She reports an occasional "popping" sound and sensation when she rises from a seated position. She has no history of trauma to the knee. She had a right clavicular fracture 2 years ago that was treated with a shoulder sling. She takes a daily multivitamin and has no known drug allergies. She does not smoke and drinks up to three glasses of wine weekly. Vital signs: Temperature 37°C (98.6°F), pulse 65/min, respirations 15/min, blood pressure 108/62 mm Hg. Height 173 cm (5 ft 8 in), weight 54 kg (119 lb), BMI 18 kg/m². Physical examination shows no acute distress. Pulmonary examination shows lungs clear to auscultation. Cardiac examination shows regular rate and rhythm with normal S1 and S2; no murmurs, rubs, or gallops. The abdomen is thin with no tenderness, guarding, masses, bruits, or hepatosplenomegaly. Extremities show no joint erythema, edema, or warmth; dorsalis pedis, radial, and femoral pulses are intact. Musculoskeletal examination shows diffuse tenderness to palpation over the right anterior knee, worse with full extension of the knee; no associated effusion or erythema; full, symmetric strength of quadriceps, hip abductors, and hip external rotators; crepitus with knee range of motion; and antalgic gait. Neurologic examination shows the patient is alert and oriented with cranial nerves grossly intact and no focal neurologic deficits. Which of the following is the most appropriate next step in management?

Intraarticular steroid injection

Goal-directed fluid therapy | Fluid and electrolyte management

GDFT Principles - Don't Just Guess, Assess!

Goal-Directed Fluid Therapy (GDFT) shifts focus from static measures (e.g., CVP, PAOP) to dynamic assessments to predict fluid responsiveness. The goal is to administer fluids only to patients who will respond with an increase in stroke volume (SV), avoiding fluid overload.

Dynamic Parameters:
- Stroke Volume Variation (SVV) / Pulse Pressure Variation (PPV): Variations > 10-15% in mechanically ventilated patients suggest fluid responsiveness.
- Passive Leg Raise (PLR): A reversible "fluid challenge." A significant ↑ in SV or cardiac output predicts responsiveness.

⭐ SVV and PPV are reliable only in controlled mechanical ventilation (tidal volume ≥ 8 mL/kg), sinus rhythm, and a closed chest. They are unreliable with spontaneous breathing or arrhythmias.

Frank-Starling Curve: Fluid Responsiveness

GDFT Monitoring - The Body's Dashboard

Frank-Starling curve: fluid responsiveness and preload

Core Principle: Shift from static measures to dynamic assessments of fluid responsiveness.

Parameter	Type	Utility in GDFT
CVP, PAOP	Static	Poor predictor of fluid responsiveness.
SVV, PPV	Dynamic	>10-15% suggests fluid responsiveness.
PLR, EEo	Dynamic	Assesses preload reserve without fluid bolus.
CO, SV	Dynamic	Direct measure of cardiac performance.
%%{init: {'flowchart': {'htmlLabels': true}}}%%
flowchart TD

Start["📋 Assess Hemodynamics
• Evaluate stability• Initial check"]

Decision["📋 SVV/PPV > 13%?
• Fluid responsive?• Check variability"]

Fluid["💊 Administer Fluids
• Give fluid bolus• Increase preload"]

Pressors["💊 Pressors/Inotropes
• Consider vasopressors• Support contractility"]

Reassess["👁️ Re-assess SV/CO
• Check stroke volume• Cardiac output"]

Start --> Decision Decision -->|Yes| Fluid Decision -->|No| Pressors Fluid --> Reassess Pressors --> Reassess

style Start fill:#FEF8EC, stroke:#FBECCA, stroke-width:1.5px, rx:12, ry:12, color:#854D0E style Decision fill:#FEF8EC, stroke:#FBECCA, stroke-width:1.5px, rx:12, ry:12, color:#854D0E style Fluid fill:#F1FCF5, stroke:#BEF4D8, stroke-width:1.5px, rx:12, ry:12, color:#166534 style Pressors fill:#F1FCF5, stroke:#BEF4D8, stroke-width:1.5px, rx:12, ry:12, color:#166534 style Reassess fill:#EEFAFF, stroke:#DAF3FF, stroke-width:1.5px, rx:12, ry:12, color:#0369A1


> ⭐ **Exam Favorite:** Dynamic parameters (SVV, PPV, PLR) are superior to static pressures (CVP, PAOP) in predicting which patients will respond to a fluid challenge with an increase in stroke volume.

## GDFT in Action - The Fluid Algorithm

![Frank-Starling curves and fluid responsiveness](https://ylbwdadhbcjolwylidja.supabase.co/storage/v1/object/public/notes/L1/Surgery_Fluid_and_electrolyte_management_Goal-directed_fluid_therapy/95f8d83f-2caf-4b1b-a381-b7948dbbd056.jpg)

*   **Core Principle:** Use dynamic assessments to guide fluid administration, avoiding both hypovolemia and fluid overload. The goal is to optimize cardiac output by placing the patient on the optimal portion of their Frank-Starling curve.

```mermaid
%%{init: {'flowchart': {'htmlLabels': true}}}%%
flowchart TD
    Start["<b>⚠️ Hypotension</b><br><span style='display:block; text-align:left; color:#555'>• Hypoperfusion signs</span><span style='display:block; text-align:left; color:#555'>• Critical state</span>"]
    
    Assess["<b>📋 Dynamic Assess</b><br><span style='display:block; text-align:left; color:#555'>• Fluid response</span><span style='display:block; text-align:left; color:#555'>• Hemodynamic check</span>"]
    
    Check["<b>🔬 SVV or PPV?</b><br><span style='display:block; text-align:left; color:#555'>• SVV > 13 pct</span><span style='display:block; text-align:left; color:#555'>• PPV > 13 pct</span>"]
    
    Fluid["<b>💊 Fluid Challenge</b><br><span style='display:block; text-align:left; color:#555'>• 250-500 mL IV</span><span style='display:block; text-align:left; color:#555'>• Use Crystalloid</span>"]
    
    SVCheck["<b>🩺 Stroke Volume</b><br><span style='display:block; text-align:left; color:#555'>• SV ⬆️ by > 10 pct?</span><span style='display:block; text-align:left; color:#555'>• Measure output</span>"]
    
    Pressors["<b>💊 Vasopressors</b><br><span style='display:block; text-align:left; color:#555'>• Consider pressors</span><span style='display:block; text-align:left; color:#555'>• Support pressure</span>"]
    
    Goal["<b>✅ Target MAP</b><br><span style='display:block; text-align:left; color:#555'>• Maintain >= 65 mmHg</span><span style='display:block; text-align:left; color:#555'>• Final goal</span>"]

    Start --> Assess
    Assess --> Check
    Check -->|YES| Fluid
    Check -->|NO| Pressors
    Fluid --> SVCheck
    SVCheck -->|YES| Check
    SVCheck -->|NO| Pressors
    Pressors --> Goal

    style Start fill:#FDF4F3, stroke:#FCE6E4, stroke-width:1.5px, rx:12, ry:12, color:#B91C1C
    style Assess fill:#FEF8EC, stroke:#FBECCA, stroke-width:1.5px, rx:12, ry:12, color:#854D0E
    style Check fill:#FFF7ED, stroke:#FFEED5, stroke-width:1.5px, rx:12, ry:12, color:#C2410C
    style Fluid fill:#F1FCF5, stroke:#BEF4D8, stroke-width:1.5px, rx:12, ry:12, color:#166534
    style SVCheck fill:#F7F5FD, stroke:#F0EDFA, stroke-width:1.5px, rx:12, ry:12, color:#6B21A8
    style Pressors fill:#F1FCF5, stroke:#BEF4D8, stroke-width:1.5px, rx:12, ry:12, color:#166534
    style Goal fill:#F6F5F5, stroke:#E7E6E6, stroke-width:1.5px, rx:12, ry:12, color:#525252

⭐ Exam Favorite: Dynamic assessments of fluid responsiveness (e.g., Stroke Volume Variation (SVV), Pulse Pressure Variation (PPV), passive leg raise) are superior to static measures (e.g., Central Venous Pressure (CVP), Pulmonary Capillary Wedge Pressure (PCWP)) in predicting which patients will respond to a fluid bolus.

Evidence & Outcomes - The Proof is in the Pudding

GDFT significantly improves outcomes in major surgery and sepsis.
Primary Benefits:
- ↓ Mortality rates
- ↓ Hospital length of stay
- ↓ Post-op complications (AKI, infections)
Greatest impact in high-risk surgical patients and septic shock.

⭐ Studies show GDFT significantly reduces acute kidney injury (AKI) and surgical site infection (SSI) rates in patients undergoing major abdominal surgery.

Complication Rates by Fluid Management Strategy

High‑Yield Points - ⚡ Biggest Takeaways

Goal-Directed Fluid Therapy (GDFT) titrates IV fluids to specific hemodynamic endpoints, moving beyond fixed-volume protocols.

Its primary aim is to optimize oxygen delivery (DO₂) and prevent tissue hypoxia and end-organ damage.

Utilizes dynamic parameters like stroke volume variation (SVV) or cardiac output to guide fluid administration.

GDFT helps prevent both hypovolemia and deleterious fluid overload, improving patient outcomes.

Key benefits include reduced postoperative complications, especially AKI and surgical site infections.

Primarily indicated for high-risk surgical patients or those in septic shock.