Starling Forces & Capillary Fluid Exchange
Electrolyte Emergencies
Monitoring Part 1
Monitoring Part 2
Positioning!
100
This Starling force pushes fluid out of the capillary and into the interstitial space.
Answer: What is capillary hydrostatic pressure?
Rationale: Capillary hydrostatic pressure creates an outward force that favors movement of fluid from the vascular compartment into the interstitium
100
Correcting chronic hyponatremia too rapidly can cause this devastating neurologic complication.
Answer: What is osmotic demyelination/central pontine myelinolysis?
Rationale: The lecture limits correction to no faster than 8 mEq/L/24 hr, or 4–6 mEq/L/24 hr in high-risk patients.
100
A patient develops an intraoperative dysrhythmia, and you need the ECG lead emphasized in the lecture for rhythm/arrhythmia detection. Which lead should you select?
Answer: Lead II
Rationale: Lead II provides the best P-wave visibility and is preferred for rhythm/arrhythmia monitoring.
100
While advancing a pulmonary artery catheter, you advance more than 10 cm beyond the expected location but never obtain the characteristic waveform for the next chamber. What complication should you suspect?
Answer: Catheter coiling
Rationale: The lecture specifically identifies this pattern as suggesting PAC coiling.
100
This nerve is the most position-specific nerve injury associated with lithotomy.
What is the common peroneal nerve?
The nerve can be compressed between the fibular head and stirrup during lithotomy.
200
This Starling force pulls fluid back into the blood vessel.
Answer: What is plasma oncotic pressure?
Rationale: Plasma oncotic pressure opposes outward filtration by attracting water toward the intravascular compartment
200
A patient with hyperkalemia develops dangerous ECG changes. This medication is administered first to stabilize the cardiac membrane.
Answer: What is IV calcium?
Rationale: Hyperkalemia treatment has three goals: stabilize the cardiac membrane, shift potassium intracellularly, and remove potassium from the body.
200
You are monitoring for myocardial ischemia rather than rhythm abnormalities. What type of ECG leads does the PowerPoint emphasize for ST-segment detection?
Answer: Precordial + limb leads
Rationale: The PowerPoint bolds this distinction: rhythm → Lead II; ischemia/ST-segment detection → precordial + limb leads.
200
During controlled ventilation, the capnogram no longer returns to zero during inspiration. The airway remains patent and ventilation continues. According to the lecture, what should you suspect first?
Answer: Exhausted CO₂ absorber
Rationale: This is the most common listed cause of an elevated capnogram baseline.
200
This positioning device can worsen venous congestion and increase IOP during prone spine surgery.
What is the Wilson frame?
The Wilson frame can increase venous congestion and IOP, contributing to ION/POVL risk
300
This plasma protein is the primary determinant of plasma oncotic pressure.
Answer: What is albumin?
Rationale: The PowerPoint specifically identifies albumin as the major determinant of the oncotic force pulling fluid into the vascular space
300
Which of the following EKG changes is specifically associated with a serum potassium level between 7.0 and 8.0 mEq/L?
Answer: What is QRS prolongation?
300
The newer evidence presented in lecture identifies another single lead with greater sensitivity. Which lead?
Answer: V3
Rationale: V3 had the highest single-lead sensitivity at 87%, compared with V4 at 79% and V5 at 66%.
Verbatim Per Slide:
Classic teaching:
V5 alone (75%) → combine with Lead II + V4 for up to 96% sensitivity
Newer evidence: single-lead sensitivity is actually highest with V3 (87%), then V4 (79%), then V5 (66%)
Bottom line: V3/V4 now preferred over V5 alone – better data, not a wrong answer
300
During an SSEP case, the anesthesia provider wants to use a volatile anesthetic while maintaining interpretable monitoring. What MAC range is specifically emphasized in the PowerPoint?
Answer: 0.5–1 MAC
Rationale: The italicized SSEP recommendation is to ideally use an inhalation agent at 0.5–1 MAC and avoid rapid changes in anesthetic depth.
300
2-Part:
Q1: During supine positioning, arm abduction should not exceed this angle to reduce brachial plexus injury.
Q2: During prone positioning, the head should be elevated approximately this amount when possible to help reduce venous congestion.
A1: What is 90°? The lecture specifically instructs avoiding arm extension/abduction beyond 90° in supine positioning.
A2: .What is 10°? The lecture recommends positioning the prone patient's head about 10° up when feasible.
400
Name all four opposing pressures governing fluid movement across the capillary wall.
Answer: What are capillary hydrostatic pressure, plasma oncotic pressure, interstitial hydrostatic pressure, and interstitial oncotic pressure?
Rationale: These are the four Starling forces presented in the lecture.
Interstitial hydrostatic & oncotic pressure are smaller opposing forces within the tissue space.
400
How does severe hypophosphatemia (P<2.0 mg/dL) impact oxygen delivery to the tissues? Hint: It _____ 2,3-DPG levels.
It decreases 2,3-DPG levels, causing a left shift in the oxyhemoglobin dissociation curve.
Severe hypophosphatemia (< 2.0 mg/dL) depletes red blood cell 2,3-DPG, causing a left shift in the oxyhemoglobin dissociation curve that increases oxygen affinity and prevents effective oxygen unloading to the tissues.
400
A patient's preoperative ECG shows ST abnormalities in specific leads. Rather than selecting ischemia-monitoring leads solely from population data, what emphasized strategy should guide your intraoperative selection?
Answer: Fingerprinting
Rationale: The PowerPoint bolds “fingerprinting”—prioritize the same leads that demonstrated ST changes on the patient's preoperative ECG.
400
2-Part:
Question 1: During evoked-potential monitoring, the waveform arrives 12% later than baseline. Which emphasized waveform characteristic has become abnormal?
Question 2: During evoked-potential monitoring, the timing of the waveform remains unchanged, but its size decreases by 55%. Which emphasized waveform characteristic is abnormal?
Q1. Answer: Latency
Rationale: The PowerPoint italicizes latency and states that an increase of ≥10% is bad.
Q2. Answer: AmplitudeRationale: The PowerPoint italicizes amplitude and identifies a decrease of ≥50% as bad.
400
3-Part:
Q1: This Grade 1 nerve injury causes temporary dysfunction after blunt force or compression.What is neuropraxia
Q2: This Grade 2 nerve injury destroys the axon and myelin but preserves the supporting matrix, allowing possible regeneration.
Q3: This Grade 3 nerve injury completely disrupts the nerve fibers, connective tissue, and Schwann sheath.
A1: Grade 1 = neuropraxia, involving relatively minor demyelination/axonal degeneration and temporary dysfunction.
A2: What is axonotmesis? Preservation of the endoneurium and Schwann sheath allows potential axonal regeneration despite Wallerian degeneration.
A3: What is neurotmesis?Neurotmesis involves loss of anatomic continuity and has little expected recovery without surgical repair.
500
How does aggressive crystalloid resuscitation typically affect Starling forces?
Hint: It _____ hydrostatic pressure and _____ oncotic pressure.
Answer: "It increases hydrostatic pressure and decreases oncotic pressure."
Rationale: The large volume increases the physical pressure against vessel walls while simultaneously diluting plasma proteins like albumin. Using large volumes of protein-free fluid dilutes the plasma proteins responsible for holding fluid inside the blood vessels, causing oncotic pressure to drop rather than rise.500
Connect the relationship: ↑ phosphate → ___ calcium, while ↓ calcium → ___ PTH.
Answer: What are ↓ calcium and ↑ PTH?
Rationale: This combines the two major inverse relationships emphasized in the electrolyte section:
↑ Phosphate ↔ ↓ Calcium
↑ Calcium ↔ ↓ PTH
Therefore: ↑ phosphate → ↓ calcium → ↑ PTH
500
A pulse-ox reading appears reassuring despite a clinical picture concerning for hypoxemia. The Perfusion Index is 0.8%. What does the emphasized PI threshold indicate?
Answer: Low perfusion
Rationale: The PowerPoint bolds PI <1% = low perfusion, which produces a less reliable signal.
500
Pulse oximetry displays 93%, but arterial saturation is 86%. According to the emphasized thresholds in the lecture, what phenomenon is occurring?
Answer: Occult hypoxemia
Rationale: The emphasized definition is a falsely reassuring SpO₂ ≥92% while true SaO₂ <88%.
500
A suspected VAE should prompt this position: left lateral decubitus combined with Trendelenburg.
What is Durant’s position?
Along with stopping N₂O, PPV, central-line aspiration, and flooding the field, the lecture recommends Durant's position when feasible.