110 Questions
What are the hemodynamic effects of chronic heart failure characterized by?
Systolic and diastolic dysfunction of left/right/both ventricles
Which of the following is NOT part of the maladaptive neurohumoral responses in chronic heart failure?
Persistent bradycardia
What is a common consequence of chronic heart failure's persistent activation of the RAA axis?
Salt and water retention
What is a potential challenge to fluid management in perioperative heart failure patients due to treatment for HF ?
Chronic volume depletion
What is the primary goal of perioperative fluid therapy in patients with heart failure?
Maintain cardiac output
Which medication used in treating heart failure aims to correct neurohumoral responses ?
Aldosterone antagonists
how to maintain good cardiac output in patients with heart failure
high CVP and adequate diastolic filling time
What can excessive intravascular volume infusion and preload lead to in a failing heart?
Impaired contractility and worsening cardiac output
What is the manifestation of 'forward failure' in heart failure patients?
Inadequate organ perfusion
Why is it important to strike a balance between hypovolemia and hypervolemia in heart failure patients?
To minimize cardiac O2 demand
What is the manifestation of 'backward failure' in heart failure patients?
Pulmonary and peripheral edema
why Measurement of cardiac filling & contractility in HF is particularly important ?
Because of intraoperative hypotension require different treatments
What should be undertaken only with objective evidence of intravascular volume loss in the perioperative phase for heart failure patients?
Infusion of large volumes of any fluid
Which electrolyte imbalance is frequently caused by loop diuretics in heart failure patients?
Hypokalemia & hypomagnesemia
How should hypotension caused by ACE-inhibitors or angiotensin receptor antagonists be appropriately treated in heart failure patients?
By small doses of inotropes or vasopressors
Which electrolyte imbalance is frequently caused by aldosterone in heart failure patients?
hypophosphatemia
Which electrolyte imbalance is frequently caused by aldosterone antagonists combined with ACE-inhibitor in heart failure patients?
severe hyperkalemia
digoxin toxicity can be potentiated by
hypokalemia
How does reduced or absent native urine production affect overall fluid balance in patients with dialysis-dependent chronic kidney disease?
Disturbs overall fluid balance
What can chronic anemia, endothelial dysfunction, and microvascular perfusion abnormalities impair in patients with dialysis-dependent chronic kidney disease?
Organ O2 delivery
In the context of kidney disease, what increase the perioperative risk ?
coexistence of heart failure and hypertension
Why is preoperative assessment important in patients with dialysis-dependent chronic kidney disease?
To assess comorbidities and optimize treatment
What is a key consideration in perioperative fluid therapy for patients with dialysis-dependent chronic kidney disease?
Ensuring normal blood volume before surgery
What is a potential consequence of undertaking surgery in the presence of hypovolemia for patients with dialysis-dependent chronic kidney disease?
Risk for anesthesia-related hypotension
In elective surgery, when is the best time to perform dialysis ?
day before surgery
when the electrolytes should be checked patients with dialysis-dependent chronic kidney disease?
on the morning of surgery
Why should large volumes of isotonic saline be avoided in patients undergoing surgery who require dialysis?
They induce acidosis favoring extrusion of K+ from cells
patients with dialysis-dependent chronic kidney disease, what is the ideal K+ value after dialysis
low-to-normal range
What is a potential risk associated with using colloid solutions for intravascular volume replacement in surgical patients requiring dialysis?
Volume effect may be exaggerated due to predominantly renal excretion
patients with dialysis-dependent chronic kidney disease, Electrolytes sampling too soon after dialysis, before equilibration, may give an
low K+ result
What is a potential consequence of undertaking surgery in the presence of hypervolemia for patients with dialysis-dependent chronic kidney disease?
poor wound healing
Which type of crystalloid did not cause hyperkalemia in clinical trials for patients undergoing surgery who require dialysis?
K+-containing balanced crystalloids
Before considering blood transfusion in surgical patients awaiting renal transplantation, why is it important to liaise with the nephrologist?
To minimize antibody formation and future matching difficulties
Why should the amount of fluid administered intraoperatively to surgical patients requiring dialysis be titrated based on objective physiologic measurements?
To ensure appropriate fluid balance
what it can be used as alternative crystalloid to isotonic or balanced solutions in patients with dialysis-dependent chronic kidney disease?
K+-free HCO3−- buffered dialysis solution
What is the recommended approach if there is not enough time for preoperative dialysis in patients requiring emergency surgery?
Conservatively managing electrolyte abnormalities
What is the primary cause of large volume gastric fluid loss resulting in a distinct pattern of fluid and acid-base abnormalities?
Congenital or acquired gastric outlet obstruction
In response to progressive dehydration due to gastric fluid loss, what hormone is secreted to retain Na+ and water?
Aldosterone
What is the initial renal response to large volume gastric fluid loss?
Formation of urine with low Cl− and high HCO3− content
What are the consequences of increased aldosterone secretion in response to progressive dehydration?
Hypokalemia and metabolic alkalosis
How does correction for large volume gastric fluid loss typically begin after rehydration?
K+ supplementation with isotonic saline
What is the paradoxical outcome observed in urine composition due to progressive dehydration from gastric fluid loss?
Acidic urine despite metabolic alkalosis
What are the consequences of increased aldosterone secretion in response to progressive dehydration?
alkalosis which reduces the circulating ionized fraction of Ca2+.
Dehydration due to Large volume gastric fluid loss, Correction should include
gradual rehydration with isotonic saline and K+ supplementation
What is a key part of the first six hours of sepsis treatment for patients as mentioned in the text?
Fluid resuscitation with the goal of maintaining adequate end organ perfusion
What contributes to cardiovascular instability in septic patients according to the text?
Sympathetic redistribution of blood away from peripheral circulation
What did early trials suggest was more effective than resuscitation guided by CVP, MAP, and urine output targets in reducing mortality from sepsis?
Protocolized fluid resuscitation targeting central venous oxygen saturation
What approach has shown similar outcomes to resuscitation based on central venous oxygen saturations according to more recent large international trials?
Resuscitation based on standard care without targeted saturations
How should fluid resuscitation be guided for septic patients with evidence of tissue hypoperfusion, based on the text?
By providing at least 30 mL/kg of crystalloid within the first 3 hours
How should fluid resuscitation be guided for septic patients with evidence of tissue hypoperfusion?
MAP >65 mm Hg in those requiring vasopressors
What is a particular issue contributing to cardiovascular instability in septic patients as mentioned in the text?
Sympathetic redistribution of blood volume away from peripheral circulation
What is recommended as a dynamic test of fluid responsiveness over static targets in fluid management?
Passive leg raise
What is the strategy for fluid therapy in patients with ARDS undergoing surgical procedures?
Balance between lung edema and tissue perfusion
In patients with established sepsis, what makes fluid management more challenging?
Microvascular dysfunction
In patients with established sepsis, which strategy is associated with improved outcomes?
less positive overall fluid balance
What is a potential consequence of excessive global O2 delivery strategies in patients with uncoupling of O2 delivery and consumption?
Potential side effects
What was observed in patients with ARDS who were treated with lower fluid volumes during surgery?
Reduced ICU days
What outcome is associated with a less positive overall fluid balance in critically ill patients?
Improved outcomes
how patients with ARDS should be treated with fluid intraoperative ?
crystalloid fluids
What is a common systemic response to extensive burns according to the text?
Localized and systemic inflammatory reactions
When is IV fluid therapy generally initiated for adults with burns, based on the text?
For burns greater than 15% total body surface area
What specifically contributes to the loss of skin integrity in burn patients, as mentioned in the text?
Evaporative transcutaneous fluid loss
Which formula is a basis for fluid administration in patients with burns, as per the text?
Parkland formula
What role does dead tissue combined with areas undergoing ischemia play in patients with extensive burns?
Causes local impairment of endothelial barrier function
What is the primary concern associated with excessive fluid administration in burned patients?
Pulmonary edema
What is a potential complication of using colloid solutions early in burn resuscitation?
Increased risk of compartment syndrome
What do large studies reveal about the fluid volumes received by most burn patients compared to what is predicted by the Parkland formula?
Patients receive more fluid than predicted
Which condition/situation is not accounted for by the formulas used for burn resuscitation according to the text?
Low urine output
What is a key component in the perioperative management of intracranial pathology?
Fluid and electrolyte therapy
What is a feature of hypoosmolar hyponatremic conditions related to brain water?
Cerebral edema
What intervention may reduce total brain water and intracranial pressure by creating brain-blood osmotic gradients?
Increasing serum sodium level
In what situation might the osmotic action of drugs like mannitol and hypertonic saline be reduced?
When BBB is disrupted by brain injury
Which factor may impair cerebral perfusion in neurosurgical patients with increased ICP?
Impaired autoregulation
What is a rational approach to fluid management in neurosurgical patients?
Maintaining baseline blood volume and cerebral perfusion
What is a potential concern associated with hypervolemia in patients with early traumatic brain injury without intracranial pressure monitoring?
Development of pulmonary edema
In the context of cerebral vasospasm treatment after subarachnoid hemorrhage, what does 'triple-H' therapy involve?
Hypervolemia, hemodilution, hypertension
What does the use of albumin in traumatic brain injury compared with isotonic saline lead to?
Increased mortality rates
What is a concern associated with maintaining a hematocrit level below 30% according to studies on vasospasm treatment?
Reduced oxygen delivery
What is the potential issue with using hypervolemia to prevent vasospasm according to the text?
Development of pulmonary edema
What is the term for the approach that involves treating the acute coagulopathy of trauma, maximizing tissue O2 delivery, and avoiding hypothermia and acidosis in patients with major traumatic hemorrhage?
Hemostatic resuscitation
What is the initial blood pressure range recommended for awake patients with penetrating trauma in the prehospital setting?
SBP of 70 to 80 mm Hg
What is a potential consequence of using large volumes of IV crystalloids or colloids in the early resuscitation of major traumatic hemorrhage patients?
Hemodilution and clotting factor dilution
Which ratio of fresh frozen plasma (FFP) to packed red blood cells (PRBC) is suggested to be associated with the best outcomes in massive transfusion for major traumatic hemorrhage?
1:1
In the context of trauma-induced coagulopathy, what intervention can be used to improve clot stability?
Tranexamic acid
What is the key goal of the initial fluid administration in patients with major traumatic hemorrhage according to the text?
Achieving cerebration
What is the primary goal of fluid resuscitation once hemostasis has been achieved?
To normalize lactate levels
In patients with traumatic brain injury and major hemorrhage, what is recommended to achieve adequate cerebral blood flow?
Use of fluids and vasopressors to achieve a MAP above 90 mm Hg
Why is the resuscitation strategy for patients with mixed intracranial & extracranial trauma based on clinical judgment?
To prioritize the requirements of the most severe injuries
What is particularly important for subsequent normalization of systemic BP in patients with traumatic brain injury?
Control of bleeding to allow normalization of BP
What is a key consideration to avoid in free tissue flap surgery to prevent threatening the perfusion of the flap?
Vasoconstriction in feeding vessels
What traditional method has been traditionally used to address the blood flow requirements for free tissue flaps, but is currently suggested to have drawbacks?
Hypervolemic hemodilution
Why is the use of dextrans to improve blood flow not favored in free tissue flap surgery?
risks for medical complications is relatively high.
What makes free tissue flaps particularly prone to interstitial edema during the post-surgery period?
Disrupted lymphatics taking weeks to reconnect
Why should large volumes of crystalloid be avoided in free tissue flap surgery?
They may cause increased capillary filtration
In free tissue flap surgery, what should be used for blood volume expansion instead of large volumes of crystalloid?
Colloids
What is a potential complication of inducing hypovolemia during liver resection?
end-organ hypoperfusion
In esophagogastrectomy, what fluid balance threshold from surgery to the second postoperative day is considered an independent risk factor for adverse outcomes?
Greater than 1900 mL
What technique is used to maintain a low central venous pressure (CVP) during liver parenchymal resection?
Conservative fluid management
What is recommended to guide fluid therapy once hepatic resection is completed?
Both invasive hemodynamic and minimally invasive cardiac output monitoring
What is the potential benefit of conservative fluid administration in thoracic surgery patients?
Minimized risk of ARDS and ALI
What is a major disruption during phase II of liver transplant surgery that may require crystalloid and colloid infusion along with vasopressors?
Major reduction in venous return
What contributes to acidosis, hypocalcemia, and hypomagnesemia during phase II of liver transplant?
Absence of citrate and lactate metabolism
What fluid-related challenge is faced during reperfusion (phase III) of liver transplant surgery?
Acute rise in CVP with hepatic congestion
What is the recommended approach to prevent hyperkalemia-related arrhythmias during liver transplant surgery?
Providing a bolus of CaCl2
What clinical manifestation may indicate systemic vasodilation and cardiac arrest during phase III of liver transplant surgery?
Hypotension requiring vasopressor support
What can lead to right heart failure after unclamping in liver transplant surgery?
Infusion of excessive crystalloids
What is a key consideration in the perioperative fluid management of patients undergoing major intraabdominal surgery?
Adjusting fluid replacement based on CVP and CO monitoring
Which electrolyte abnormalities are frequently observed due to fluid redistribution in patients undergoing major intraabdominal surgery?
Hypokalemia & hypomagnesemia
What is a primary goal of fluid therapy in the perioperative management of renal transplant patients?
Ensuring adequate renal perfusion for early graft function
What can be valuable in the perioperative period for patients undergoing major gynecologic operations or urologic procedures?
Serial blood gas analysis
Study Notes
Patients with Dialysis-Dependent Chronic Kidney Disease
- Multiple pathologic features must be considered in perioperative fluid therapy:
- Reduced or absent native urine production
- Reliance on dialysis to achieve target "dry" weight
- Organ O2 delivery may be impaired by chronic anemia, endothelial dysfunction, and microvascular perfusion abnormalities
- Preoperative assessment should focus on:
- Adequacy of chronic dialysis in attaining euvolemia
- Estimating normal volume of native urine output
- Comorbidities should be assessed and optimized
- Surgery should be undertaken in a facility with preoperative and postoperative dialysis or hemofiltration capabilities
- Elective surgery: preoperative dialysis should be timed to allow for equilibration of fluid and electrolyte compartments
- Surgery in the presence of hypervolemia increases risk of:
- Pulmonary and peripheral edema
- Hypertension
- Poor wound healing
- Hypovolemia increases risk of:
- Anesthesia-related hypotension
- Inadequate tissue perfusion
Patients with Heart Failure
- Perioperative fluid management is particularly challenging due to:
- Diverse pathophysiologic effects of heart failure and its treatment
- Neurohumoral responses
- Goals of perioperative fluid therapy:
- Preserve cardiac output
- Minimize cardiac work
- Importance of avoiding:
- Hypovolemia
- Hypervolemia
- Inadequate tissue perfusion
- Practical approach:
- Careful preoperative assessment of fluid status and electrolytes
- Optimization of heart failure treatments when time allows
- Cardiac output monitoring for moderate or major surgery
- Infusion of large volumes of fluid should be undertaken only with objective evidence of intravascular volume loss
Neurosurgery
- Multiple physiologic factors affect fluid and electrolyte therapy in perioperative management of intracranial pathology
- Disturbances of water and Na+ balance may be caused by:
- Neurosurgical diseases themselves
- Diabetes insipidus
- Cerebral salt wasting
- SIADH
- Rational management of fluids:
- Maintain baseline blood volume and cerebral perfusion
- Avoid significant decreases in serum Na+, osmolality, and oncotic pressure
- Specific situations:
- Increased intracranial pressure: use mannitol and hypertonic saline to reduce total brain water
- Cerebral vasospasm: manipulation of hemodynamics and hematocrit is traditionally used
Upper Gastrointestinal Loss
- Large volume gastric fluid loss may lead to:
- Dehydration
- Reduced total body Cl- content
- Alkalosis
- Hypokalemia
- Correction:
- Gradual rehydration with isotonic saline and K+ supplementation
- Change to dextrose-containing saline solutions depending on electrolyte analysis
Trauma
- Key goals:
- Avoid clot disruption until definitive control of bleeding
- Treat acute coagulopathy of trauma
- Maximize tissue O2 delivery
- Avoid hypothermia and acidosis
- Hemostatic resuscitation:
- Permissive hypovolemia
- Rapid transfer for damage control intervention
- Limited use of IV crystalloids or colloids
- Early replacement of PBRCs, clotting factors, and platelets
Sepsis and Acute Lung Injury
- Fluid management is challenging due to:
- Microvascular dysfunction
- Extravascular fluid overload
- Disturbed neurohumoral responses
- Strategies:
- Less positive overall fluid balance is associated with improved outcomes
- Focus on fine balance between avoiding increased lung edema and maintaining adequate tissue perfusion
- Conservative fluid administration strategy
- Use of extravascular lung water (EVLW) measurement to predict worse outcomes### Thoracic Surgery
- Postoperative respiratory problems, including ARDS and ALI, can occur in any thoracic procedure, including upper GI and thoracic surgery.
- One-lung ventilation contributes to the development of ARDS and ALI, along with patient and surgical risk factors.
- Restrictive fluid strategies may reduce pulmonary complications in esophagogastrectomy patients.
Hepatic Resection
- Blood loss during liver resection is associated with high venous pressure and backflow of blood through valveless hepatic veins.
- Maintaining a CVP of 5 cm H2O or lower is associated with reduced blood loss and transfusion requirements.
- Conservative fluid management is recommended, at least until the hepatic resection is completed, to minimize blood loss and transfusion requirements.
Free Tissue Flap Surgery
- Free tissue flaps are often used in oncoplastic surgery and involve autologous transplantation of tissue.
- Transplanted vessels lack intrinsic sympathetic tone, and vasoconstriction in feeding vessels must be avoided to maintain perfusion of the flap.
- A conservative fluid strategy is recommended to improve flap outcome and avoid excessive fluid administration.
Intrathoracic Procedures
- Extensive burns can lead to copious fluid loss, systemic inflammation, and endothelial barrier dysfunction.
- Fluid administration should aim to maintain adequate circulating volume, guided by invasive hemodynamic monitoring and minimally invasive cardiac output monitoring.
Burns
- Thermal injury leads to localized and systemic inflammatory reactions, impairment of endothelial barrier function, and fluid loss.
- IV fluid therapy is instituted for burns greater than 15% total body surface area in adults and 10% in children.
- Fluid administration should be based on physiologic goals, rather than formulas, to avoid excessive fluid administration.
Major Intraabdominal Surgery
- Operations involving multiple organ resections for tumor require careful perioperative fluid management.
- Intraoperative drainage of ascites can lead to significant fluid shifts, requiring CO monitoring and serial blood gas analysis.
Renal Transplant
- Perioperative fluid therapy goals are to ensure adequate renal perfusion and avoid fluid therapy side effects.
- CVP-guided intraoperative fluid therapy is advocated, using balanced crystalloid solutions and avoiding large volumes of crystalloid infusion.
Liver Transplant
- Liver transplant involves a series of major physiologic disruptions requiring invasive monitoring and data-guided fluid therapy.
- Therapy should be guided by data from invasive monitoring, including PAC, and address the various phases of liver transplant, including pre-anhepatic, anhepatic, and reperfusion phases.
Explore the challenges and considerations in perioperative fluid management for patients with heart failure. Learn about the diverse pathophysiologic effects of heart failure and their treatment, including the hemodynamic effects and maladaptive neurohumoral responses.
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