Abdominal Compartment Syndrome Flashcards

1
Q

What is Abdominal Compartment Syndrome (ACS)?

A

Pathological condition caused by sustained elevations in intraabdominal pressure, leading to organ dysfunction and end-organ failure

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2
Q

What is the difference between primary and secondary ACS?

A

-Primary ACS originates from pathologic processes in the abdomen, like peritoneal hemorrhage.
-Secondary ACS arises from systemic processes, such as sepsis or large-volume resuscitation.

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3
Q

What conditions are associated with secondary ACS?

A

Secondary ACS is associated with conditions like sepsis, large-volume resuscitation, massive transfusion, and inflammation, which increase capillary permeability.

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4
Q

What are the primary strategies for reducing intraabdominal pressure (IAP) and managing refractory intraabdominal hypertension (IAH)?

A

The strategies include evacuating space-occupying masses and collections, decompression of intraluminal content, improving abdominal wall and diaphragm compliance, and optimizing fluid management.

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5
Q

What simple maneuvers can help reduce intraabdominal pressure?

A

-Nasogastric and rectal tube decompression help reduce intraabdominal pressure
-Intestinal promotility agents can help evacuate intraluminal content and gas, in cases of gastric or intestinal obstruction, severe dysmotility, or large fecal burden
-percutaneous drainage catheters into space-occupying collections can effectively lower IAP, particularly when a substantial volume (e.g., ~1 L) is drained

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6
Q

How does increased intraabdominal pressure (IAP) affect the inferior vena cava?

A

causes compression of the intraabdominal inferior vena cava, decreasing venous return to the heart, reducing cardiac preload, and leading to systemic hypotension.

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7
Q

What is the impact of increased IAP on the thoracic cavity and ventilation?

A

decreases compliance, and increases peak airway and plateau pressures on the mechanical ventilator, potentially causing barotrauma and compressive atelectasis, leading to poor gas exchange, refractory hypoxia, and hypercarbia.

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8
Q

How does intraabdominal hypertension affect renal function?

A

decreased urine output, declining glomerular filtration rate (GFR), or increased creatinine levels due to poor systemic perfusion and direct compression of the renal system by increased intraabdominal pressure

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9
Q

What are the late findings in Abdominal Compartment Syndrome (ACS)?

A

include intestinal and solid organ ischemia, which can present as metabolic acidosis with increasing lactate levels, renal failure, or abnormal liver function tests (LFTs)

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10
Q

How frequently should intraabdominal pressure (IAP) be monitored in patients at risk for ACS?

A

should be monitored every 4 to 6 hours in patients at risk for ACS.

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11
Q

What is the standard modality for measuring intraabdominal pressure?

A

Trans-bladder pressure monitoring is the standard modality for measuring intraabdominal pressure

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12
Q

Describe the standard technique for bladder pressure measurement in IAP monitoring.

A

instilling 25 mL of normal saline via a Foley catheter, connected to a transducer placed at the midaxillary line at the level of the iliac crest, in a supine and relaxed patient. The pressure is measured at the end of expiration when the abdominal wall is relaxed.

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13
Q

What defines Abdominal Compartment Syndrome (ACS)?

A

sustained intraabdominal hypertension (IAH) > 20 mm Hg combined with new or worsening organ dysfunction

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14
Q

Grading of Intraabdominal Hypertension

A

-Grade I IAP is between 12–15 mm Hg
-Grade II IAP is between 16–20 mm Hg
-Grade III IAP is between 21–25 mm Hg
-Grade IV IAP is greater than 25 mm Hg

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15
Q

What is the definitive management for Abdominal Compartment Syndrome (ACS)?

A

emergent decompressive laparotomy.

Bedside decompressive laparotomy > IF hemodynamic instability, respiratory compromise, severely elevated intracranial pressure, or other barriers to transport.

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16
Q

How can bedside surgical decompression confirm the diagnosis of ACS?

A

diagnosis of ACS is often confirmed if hemodynamics or ventilator mechanics improve following decompression.

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17
Q

What is the purpose of a hybrid approach to managing ACS in critical settings?

A

performing a sharp laparotomy with temporary abdominal dressing at the bedside to rapidly relieve pressure
followed by transporting the patient to the operating room once hemodynamic or pulmonary decompensation has improved for further exploration and management.

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18
Q

Why is a limited laparotomy inadequate in ACS management?

A

limited laparotomy may be insufficient for complete release of pressure, leading to a risk of therapy failure and recurrent ACS, similar to extremity compartment syndrome.

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19
Q

How can improvements in the patient’s condition confirm the diagnosis of ACS?

A

through improvements in hemodynamics, intracranial pressure (ICP), peak airway pressures, cardiac output, or oxygenation, often observed after decompressive laparotomy

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20
Q

What should be done if minimal improvement is observed after initial decompression?

A

the midline incision should be extended through both the skin and fascia to ensure adequate decompression.

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21
Q

What is the role of intraoperative exploration during ACS surgery?

A

to evaluate any associated intraabdominal pathology, such as bowel ischemia or infection, which may require further surgical intervention

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22
Q

What is the purpose of Temporary Abdominal Closure (TAC)?

A

allows the surgical procedure to be paused with the abdominal fascia open, preventing reexacerbation of intraabdominal hypertension (IAH) and allowing for safe transition to other urgent patient needs or “second-look” explorations

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23
Q

How has the use of Temporary Abdominal Closure evolved?

A

with vacuum-assisted negative pressure wound therapy now commonly used across multiple specialties

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24
Q

What should a Temporary Abdominal Closure technique provide?

A

adequate visceral protection
allow drainage of intraabdominal fluid
mitigate fascia edge retraction
prevent the redevelopment of IAH and compartment syndrome.

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25
Q

What was one of the earlier techniques used for rapid abdominal closure in surgery?

A

skin-only closure, achieved either by placing penetrating towel clips 2 cm apart or using a continuous running monofilament suture to approximate the skin edges.

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26
Q

What were the limitations of skin-only closure techniques

A

Did not allow sufficient expansion of abdominal contents, retained significant risk for recurrent ACS, did not allow fluid egress, and caused damage to skin edges, leading to retraction of the abdominal wall musculature and fascia.

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27
Q

Why do skin-only closure techniques increase the difficulty of subsequent closure attempts?

A

do not prevent abdominal wall retraction or adhesions to the lateral abdominal wall, making future closure attempts more difficult and worsening the loss of abdominal domain

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28
Q

What materials are used as a protective cover over the viscera in a resource-limited setting for preventing intraabdominal hypertension (IAH)?

A

A sterile x-ray cassette cover or a 3-L sterile irrigation bag cut to size is used as a nonadherent, easily distensible protective cover over the viscera

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29
Q

How is the protective cover secured to the skin or fascial edges in this technique?

A

-circumferentially approximated to the skin or fascial edges using running small bites of heavy monofilament sutures.
-placing closed-suction drains

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30
Q

What are the disadvantages of this technique?

A

inability to prevent fascial retraction and loss of domain, increased difficulty of future fascial closure due to adhesion formation, risk of bowel injury during suturing, and being more labor-intensive compared to newer techniques.

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31
Q

What is the Barker vacuum pack, and how does it differ from the Bogota bag?

A

The Barker vacuum pack is a development from the Bogota bag.

It uses a sterile polyethylene sheet with small fenestrations placed between the viscera and the anterolateral abdominal wall to prevent adhesion formation, with saline-soaked towels and closed drains layered over the sheet to allow effective fluid drainage.

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32
Q

What is the AbThera vac, and how does it improve on the Barker vacuum pack technique?

A

The AbThera vac is a prepackaged, vacuum-assisted dressing system that includes polyurethane foam, a fenestrated non-adherent polyethylene sheet, and a negative pressure pump.

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33
Q

When is the abdomen typically closed after the acute resuscitative phase in surgical management?

A

-once hemorrhage and contamination sources are controlled
-surgical reconstruction is complete
-patient shows physiological normalization, such as weaning off vasopressors, reduced fluid requirements, improved tissue perfusion, and resolved coagulopathy.

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34
Q

Why might primary closure of the abdomen be delayed after large-volume resuscitation?

A

Large-volume resuscitation can cause visceral congestion, making the abdominal contents too large for the abdominal wall to close properly

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35
Q

What risks increase with prolonged open abdomen?

A

increases the risk of visceral adhesions
injury during manipulation
enteroatmospheric fistula
lateral abdominal wall retraction

leading to a loss of domain and a larger fascial gap, making primary closure more difficult.

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36
Q

How does prolonged open abdomen affect the lateral abdominal wall musculature?

A

The longer the abdomen remains open, the more the lateral abdominal wall musculature retracts, leading to a loss of domain and an enlargement of the fascial gap

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37
Q

What factors can affect the timing of adhesion formation in an open abdomen?

A

depends on the patient’s underlying comorbidities, physiological state, degree of malnutrition, and immunosuppression

38
Q

What is the ideal timeframe for attempting abdominal closure after resuscitative surgery?

A

The ideal timeframe for attempting abdominal closure is within 7 days, provided the patient can be anatomically and physiologically optimized

39
Q

What is the preferred method of abdominal closure for patients who clear the resuscitative fluid burden and maintain abdominal muscular domain?

A

Primary approximation of the fascia is optimal for these patients.

40
Q

What suture materials are recommended for primary fascial closure?

A

Interrupted closure with #0 or #1 polydioxanone (PDS) or polyglycolide-trimethylene carbonate (Maxon) sutures is recommended.

41
Q

What are the benefits of using polydioxanone (PDS) or Maxon sutures for fascial closure?

A

retain tensile strength for 40–90 days, which allows for extended time for fascial healing, and decrease the risks of infection or suture granuloma associated with permanent suture materials.

42
Q

What are retention sutures, and when are they used?

A

-risk-reduction strategy used for patients at increased risk of poor fascial healing.

-useful when the fascia can be closed primarily, but the patient has substantial risk factors for fascial dehiscence and would poorly tolerate evisceration or may lack access to rapid surgical care.

43
Q

What type of suture material is commonly used for retention sutures?

A

-Heavy #2 nylon sutures are commonly used for retention sutures.
-placed either in an interrupted or mattress fashion through the skin and fascia, lateral to and across the midline wound.

44
Q

What is sequential fascia closure, and how is it performed?

A

involves interrupted closure of the most superior and inferior portions of the wound until the tension becomes too high to approximate.

The remainder of the defect is then temporarily closed with a closure apparatus, and the process is repeated in subsequent surgeries

45
Q

What is the goal of sequential fascia closure in abdominal surgery?

A

progressively close the fascia while limiting fascial retraction
eventually achieving full closure or reducing the size of the defect to use a smaller bridging mesh.

46
Q

What happens if the fascia cannot be fully closed using sequential closure

A

a smaller bridging mesh can be used to close the remaining defect

47
Q

What technique for sequential fascia closure is described by the Denver group?

A

placing a protective layer of white wound vac sponge over the bowel
followed by interrupted full-thickness fascia bites using heavy monofilament sutures placed 5 cm apart, starting from the inferior and superior parts of the incision and meeting in the center.

48
Q

How often does the patient return to the operating room if fascia closure is not achieved during the initial attempt?

A

returns to the operating room every 48 hours until primary fascia closure is achieved

49
Q

What is the “piano wire” effect, and why is it a disadvantage of this technique?

A

The “piano wire” effect refers to the risk of firm, tense monofilament sutures causing deep pressure necrosis of the fascia, potentially injuring the underlying bowel.

50
Q

What are the risks associated with repeated fascia injury in sequential closure?

A

Repeated fascia injury can increase the risk of fascia dehiscence, evisceration, and hernia defect formation due to the repetitive placement of sutures

51
Q

What factors should be considered when deciding between progressive closure and abdominal wall reconstruction techniques?

A

The decision should balance the degree of visceral edema and the potential for further diuresis as the patient’s inflammatory state improves, against the extent of fascial retraction and loss of domain

52
Q

When should abdominal wall reconstruction techniques be considered?

A

These techniques should be considered when fascial retraction and loss of domain have progressed beyond what can be improved with further fluid optimization.

53
Q

What is the role of fascio-cutaneous flap elevation in managing the open abdomen?

A

allows a few centimeters of fascial advancement, which can help reduce tension and achieve a safe primary closure when the residual defect is less than 5 to 8 cm

54
Q

What are the risks associated with fascio-cutaneous flap elevation?

A

flap/skin ischemia, necrosis, and infection under the flap,

especially in patients with small-vessel vascular disease, diabetes, significant smoking history, thin subcutaneous tissue, or larger flaps

55
Q

What are the risks of more complex tissue rearrangements like component separation in emergency surgery patients?

A

More complex tissue rearrangements, such as retrorectus dissection with transversus abdominis release, should be used sparingly due to their potential to limit future surgical repair options if abdominal closure fails during the index admission.

56
Q

What is the goal of using a bridging mesh in abdominal wall management?

A

preserve fascial integrity
limit retraction of abdominal musculature
prevent abdominal fluid and protein losses
protect the viscera
facilitate epithelial closure (with flaps or skin grafting), and avoid compromising future abdominal wall reconstruction attempts.

57
Q

What types of mesh are preferred for abdominal closure in patients with open abdomens, and why?

A

Biologic or absorbable biosynthetic mesh is preferred because it degrades slowly, is replaced by native tissue, and minimizes the risks of infection, fistula, and intestinal erosion seen with permanent synthetic mesh.

58
Q

How does biologic mesh benefit patients with contaminated or high-bioburden wounds?

A

Biologic mesh incorporates into the body as it degrades, allowing tissue ingrowth and minimizing infection-related complications

59
Q

What role does biologic or absorbable synthetic mesh play in cases where the overlying tissue cannot cover the wound?

A

In such cases, the mesh can serve as a substrate for tissue ingrowth and facilitate epithelial closure, potentially with the addition of a skin graft.

60
Q

How does having an open abdomen contribute to a hypercatabolic state?

A

open abdomen leads to high energy expenditure, severe protein loss, and significant lean body mass turnover,

resulting in worsened malnutrition, immunocompromise, elevated infection risk, poor wound healing, longer ICU stays, and increased mortality.

61
Q

Why is optimizing the nutritional status important in patients with an open abdomen?

A

it helps prevent malnutrition, supports immune function, improves wound healing, and reduces the risk of complications and mortality in critically ill patients

62
Q

What is the NUTRIC score, and how is it used?

A

The NUTRIC score is a validated nutritional risk assessment tool for critically ill patients.

It helps calculate the risk of adverse events that can be mitigated with nutritional support.

A score greater than 5 identifies patients at high nutritional risk

63
Q

When should early enteral nutrition be initiated in patients with an open abdomen?

A

Early enteral nutrition should be initiated within 24 to 48 hours in all patients with an open abdomen

unless contraindicated by conditions like massive fluid resuscitation, high-dose vasopressor use, or intestinal discontinuity

64
Q

What are the benefits of early enteral nutrition in patients with an open abdomen?

A

earlier fascial closure, lower rates of fistula formation, reduced infectious complications, and decreased mortality

65
Q

When is total parenteral nutrition (TPN) considered for patients with an open abdomen?

A

TPN is considered for patients with contraindications to enteral nutrition or those unable to meet at least 60% of their daily nutritional intake.

66
Q

When should supplemental total parenteral nutrition be initiated in patients at low nutritional risk?

A

-In patients at low nutritional risk who cannot meet caloric goals, supplemental TPN should ideally be started by day 7 to avoid overfeeding complications

-In high-risk patients unable to receive enteral nutrition, TPN should be started earlier, around days 3 to 4, as studies show superior outcomes with this timing

67
Q

Why is fluid management critical in patients with an open abdomen?

A

Patients with an open abdomen often require large volumes of fluid resuscitation to support gastrointestinal, peritoneal, and insensible losses.

Mismanagement of fluid can lead to setbacks and complications such as visceral congestion, bowel edema, and recurrent Abdominal Compartment Syndrome (ACS).

68
Q

What factors should be considered in fluid calculations for open abdomen patients?

A

Insensible fluid losses from the open peritoneum and direct losses from large-volume abdominal drainage should be considered in fluid calculations to avoid underestimation.

69
Q

Why is urine output not always a reliable indicator of fluid status in critically ill patients?

A

because it can be influenced by various factors unrelated to actual fluid status.

70
Q

What additional tools can be used to assess fluid status and management in complex cases?

A

bedside echocardiography
arterial waveform analysis
or direct measurement of hemodynamics with a pulmonary artery catheter

can improve precision in fluid and vasoactive medication management.

71
Q

What is the risk of excessive fluid administration in patients with an open abdomen?

A

lead to visceral congestion, bowel edema, and make attempts at primary fascial closure challenging, as well as increase the risk of recurrent ACS.

72
Q

What is the role of direct peritoneal resuscitation (DPR) in managing patients with an open abdomen

A

used during damage control surgery, can reduce the need for crystalloid administration, decrease the inflammatory response, reduce bowel edema, and help achieve early primary fascial closure.

73
Q

What is an enteroatmospheric fistula?

A

abnormal communication between the intestinal lumen and the external environment, characterized by a large-diameter defect and a lack of a tract through other tissues.

74
Q

How does an enteroatmospheric fistula differ from an enterocutaneous fistula?

A

enteroatmospheric fistula lacks a tract through other tissues, which increases the risk of undrained intraabdominal collections and makes spontaneous closure highly unlikely.

75
Q

What complications are associated with enteroatmospheric fistulae?

A

uncontrolled spillage of intestinal content into the wound, failure of fascial or mesh closure, skin breakdown, and complex wound care needs, often preventing progress out of critical care.

76
Q

What are the risks of uncontrolled spillage from an enteroatmospheric fistula?

A

Uncontrolled spillage can lead to sepsis, wound contamination, failure of fascial closure or mesh, and ongoing skin breakdown.

77
Q

What are the risk factors for developing an enteroatmospheric fistula?

A

large-volume crystalloid administration
multiple abdominal reexplorations,
intestinal anastomosis, and large bowel resection.

78
Q

What are the key focus areas in the management of enteroatmospheric fistulae?

A

controlling and directing drainage
anatomic characterization
wound care
fluid/electrolyte/nutritional planning
and long-term operative strategy

79
Q

How is sepsis controlled in patients with enteroatmospheric fistulae?

A

diverting enteric contents to prevent their accumulation, transforming an uncontrolled fistula into a controlled (ostomy-like) fistula

80
Q

What is the goal of acute surgical intervention for an enteroatmospheric fistula?

A

The goal is not to repair the fistula but to control it, often by transforming it into a controlled fistula, rather than focusing on closure or take-down during the acute phase

81
Q

What techniques are commonly used to control an enteroatmospheric fistula?

A

Techniques include tube diversion (e.g., insertion of a large Malecot tube)
sump drain placement
wound vac therapy
wet-to-dry dressings, and maturing the fistula to the skin.

82
Q

Why is excision and direct repair of an enteroatmospheric fistula rarely successful?

A

Most patients have severe visceral adhesions that make excision and repair challenging, so resection and reanastomosis are often required, but these may not be feasible during the initial admission

83
Q

Why is controlling fistula output critical in the management of enteroatmospheric and enterocutaneous fistulae?

A

Uncontrolled output is highly caustic
causing recurrent wound infections, skin breakdown, and significant pain
making effective management essential to prevent these complications

84
Q

What are “chimney” appliances, and how are they used in fistula management?

A

Chimney appliances are purposely manufactured or improvised devices used to isolate fistula drainage into an ostomy appliance, allowing for granulation and skin grafting of the surrounding wound.

85
Q

What technique can be used for challenging cases of fistula management?

A

A pediatric silo conduit can be sutured to the ostomy opening for enteral diversion, combined with circumferential excision of surrounding tissue, placement of a wound vac sponge, and the application of negative-pressure wound therapy

86
Q

What is the role of a split-thickness skin graft in fistula management?

A

A split-thickness skin graft is applied 7 to 10 days after wound vac therapy to provide a stable, epithelialized surface for long-term placement of an ostomy appliance

87
Q

What imaging techniques can be used to anatomically map a fistula?

A

CT with enteral contrast or fluoroscopic sinography

88
Q

How does the location of a fistula along the gastrointestinal tract affect management?

A

Distally located fistulae are more likely to have modest output and allow enteral nutrition without severe fluid and electrolyte loss

while more proximally located fistulae tend to have higher output and greater risk of dehydration and electrolyte imbalance.

89
Q

How can the response of a fistula to enteral nutrition be assessed?

A

A trial of enteral feeding can help determine how the fistula responds, especially if its behavior is unclear.

90
Q

What nutritional support is typically required for patients with high-output enteroatmospheric fistulae?

A

require a prolonged course of total parenteral nutrition (TPN) for 6 to 12 months before they are safe for operative fistula takedown

91
Q

What surgical procedure is commonly performed alongside fistula takedown?

A

Fistula takedown is typically performed in conjunction with complex hernia repair