Anesthesia for Laparoscopic and Robotic Assisted Surgery (Part 1) Flashcards by Collin Morris

_____ is performed for more complex diagnostic and therapeutic procedures and has almost entirely replaced traditional open approaches.

Laparoscopy

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____ provide surgeons with improved dexterity and therefore greater stability of surgical instruments and improved outcomes.

Robotics

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The benefits of laparoscopy include:

-Safer
-Less painful
-Minimally invasive alternative to open procedure
-Faster recovery times
-Decreased LOS
-Decreased infection
-Improved patient satisfaction

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Some disadvantages of minimally invasive surgery:

-Pneumoperitoneum seqeula
*Entry into abdominal cavity and establishment of pneumoperitoneum are responsible for most significant problems that occur
-Positioning challenges
-Specialized training to use the equipment

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Successful creation of artificial pneumoperitoneum requires what:

Proper installation of air or gas into the peritoneal cavity under controlled pressure

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The two most common techniques for establishment of pneumoperitoneum are

Closed technique
Open (Hasson) procedure

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What has become the gas of choice for pneumoperitoneum creation? Why?

CO2.
-It is nontoxic, nonflammable, and readily absorbed into the blood stream with low risk of air embolization.
-Also produces less hemodynamic changes

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The ____ technique involves the use of a spring-loaded needle known as aVeress needleto pierce the abdominal wall at its thinnest point, around the umbilicus.

Closed

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The ____ technique involves the development of a 1- to 2.5-mm midline vertical incision that begins at the lower border of the umbilicus and extends through the subcutaneous tissue and underlying fascia.

Open

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___ ___ is responsible for most of the complications in laparoscopy.

Initial entry

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The magnitude of pt response to the pneumoperitoneum depends on:

Degree of IAP
Length of surgery
Position of pt
Volume status
Age and/or co-existing disease

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Insufflation of the pneumoperitoneum is associated with what hemodynamic changes?

-Increased MAP, SVR, HR
-Release of neuroendocrine hormones (vaso, renin) due to intra-abdominal vessel compression
-Decrease in SV due to decreased venous return

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Insufflation of the pneumoperitoneum is associated with what hemodynamic changes?

-Increased MAP, SVR, HR
-Release of neuroendocrine hormones (vaso, renin) due to intra-abdominal vessel compression
-Decrease in SV due to decreased venous return

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T/F: The increase in MAP and SVR is only observed if the pneumoperitineum is created under high pressure.

FALSE.
-Increased MAP and SVR were observed in low pressure (12 mmHg) and high pressure (20 mmHg) creation.

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Control patients experienced a CO reduction of ___-___%

25-50%
-This can be reduced with adequate fluid loading
-Can also assist in helping maintain SV

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Methods that can help with maintaining SV in these pts:

-Adequate fluid loading
-Correct patient positioning
-Compression stockings to augment VR

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Changes in _____ are found to have a GREATER effect on cardiac filling pressures than the pneumoperitoneum does

Positioning
**A starred and bolded point

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The ___ position is associated with increased venous return –> increased intracranial pressures –> increased ocular pressures, etc.

Trendelenburg

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The ____ ____ position is associated with reduced cardiac preload –> reduced CO.

Reverse Trendelenburg

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____ ____ is described as a PaCO2 concentration of >___ and DOES cause myocardial depression and arrhythmias.

Severe hypercarbia
PaCO2 >60
-Mild hypercarbia (45-60) has little CV effect

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Pneumoperitoneal effects on CV conduction can include:

-Prolonged QT leading to ventricular instability
-Bradycardia due to parasympathetic stimulation
-Increased arrhythmias
*don’t forget that positioning has greater effect, but pneumoperitoneum still does have a role

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In the elderly population we can see a greater ____ in MAP and ____ in CVP.

Greater decrease in MAP
Greater increase in CVP

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3 overarching categories of pulmonary effect by pneumoperitoneum:

Displacement of thoracic structures
Alteration in lung mechanics
Disruption of gas exchange

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Displacement of structures specifically effects the _____.

Diaphragm. Shifts cephalad and affects lung mechanics

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Pneumoperitoneum causes what changes in lung mechanics?

-Decreases compliance, FVC, FEV1, FRC -Increases PIP **Positioning in the steep trendelenburg position may exacerbate these changes.

Maximum absorption of CO2 is noted at the intra-abdominal pressure of ___ mmHg.

10 mmHg

Increased PaCO2 from using CO2 in the pneumoperitoneum has to be offset by what?

Increased minute ventilation (tidal volume (x) rr)

Misplaced trocars can allow for CO2 to track in what space?

Subcutaneous space

Inhalation agents ____ the HPV (hypoxic pulm vasoconstrictor) reflex.

Attenuate (decrease effectiveness)

Controlled mechanical ventilation with what changes maintain normocarbia in these pts?

1. 20-30% increase in minute ventilation 2. Increases in tidal volume instead of RR 3. Pressure control more effective than volume control

What "lung protective strategies" will we use in these pts?

1. 6-8 mL/kg 2. 6-8 cmH2O for PEEP 3. Performing intra-operative recruitment maneuvers q30 mins

Highest risk patients for pulmonary effects of pneumoperitoneum

-Anyone with even marginal cardiopulmonary dysfunction -COPD patients -?Morbidly? obese **ITS EXTREME SMH**

T/F: Mild pulmonary dysfunction is normal after laparoscopic surgery with pneumoperitoneum

TRUE. -We will often observe them in a restrictive breathing pattern as effects of pain meds and anesthesia wear off. -If it was a prolonged procedure, they may also have lingering effects of CO2 from insufflation

Renal effects of pneumoperitoneum

-Increased cr clearance -Decreased urine output, renal blood flow (renal vasoconstriction) -ADH, renin, aldosterone release

____% of patients will have elevated liver enzymes after pneumoperitoneum.

50% -Decrease in liver perfusion and possible intestinal ischemia

Immunologic effects of pneumoperitoneum

-Negative effect on local immune response -Altered proinflammatory cytokines + angiogenic factors -Possible cancer cell growth -Negative effect on wound healing

Major complications are very rare in laparoscopic sx. However, when it does occur it is associated with high ____ and ____.

Morbidity and mortality

More than ___% of all complications occur during entry into the abdomen / insertion of trocars.

50%

Most common trocar insertion injuries:

-Intestinal, urinary tract, vascular injury -CO2 embolus* -30-50% of these go unnoticed attributing to high mortality due to lack of action

Mortality as high as ___% is reported with bowel or vascular injuries.

30%

>50% of ____ injuries go unrecognized intraoperatively and lead to peritonitis, sepsis, and possible multisystem organ failure.

Intestinal -Use NG/OG tubes to decompress if noticed -Hasson (open) technique has lower visceral injury rates

If the patient has a high risk of urinary tract injury due to the procedure what should we do?

Place a foley and give methylene blue -Allows for easy recognition

T/F: Placement of the primary trocar under low pressure allows for the safest placement.

FALSE. -Trocar placement under high pressure (~25mmHg - says 20mmHg earlier in PP) allows for safest placement due to larger distance between structures.

A ___ ____ is a direct entrainment of air/other medical gas into the venous or arterial system.

Gas embolism -Can be life threatening with mortality up to 28% -Occurs when open vessels with lower intravascular pressure than intra-abdominal pressures

T/F: Most laparoscopic cases cause minor CO2 gas embolisms which can cause cardiopulmonary changes, but they resolve spontaneously

TRUE.

Signs and symptoms of CO2 gas embolism

-Low EtCO2 and high EtN2 -Hypotension and hypoxia -Tachycardia, dysrhythmias, hemodynamic instability

Low ____ increases the risk of venous gas embolism.

Low CVP -Adequate hydration for pts going for laparoscopic sx

Diagnosis of CO2 gas embolism

*TEE gold standard* but also, MILL WHEEL

CO2 embolism management

1. D/c insufflation give 100% O2 2. Release pneumoperitoneum 3. Flood surgical field with saline 4. Place in left lateral position 5. Aspirate gas via central line if we have one 6. Support hemodynamics

Due to migration of air to adjacent body cavities, we can also see what in these pts?

-Unilateral or bilateral pneumothorax -Pneumomediastinum -Pneumopericardium

Although pneumothorax, pneumomediastinum, and pneumopericardium are rare - we see them most in lap ____ surgery.

Esophageal

A pneumothorax caused by CO2 insufflation is usually treated how?

Self-resolving no intervention

A pneumothorax caused by barotrauma is usually treated how?

Surgical decompression and chest tube placement

Pneumothorax risk factors:

-Lap esophageal surgery -Surgery >200 mins -EtCO2 >50 -Bad surgeon / inexperience

Pneumothorax signs and symptoms

-High PIP with low O2 sat and no breath sounds -Hypotension / tachycardia

Occurs as a result of gas entry into subcutaneous tissue

Subcutaneous emphysema

T/F: Most cases of subcutaneous emphysema are clinically insignificant and spontaneously resolve.

TRUE -Severe cases can sometimes cause severe hypercarbia and hemodynamic instability

Why CO2 for insufflation over other choices?

Again, nontoxic, inflammable, safe in the body. > Air or N2O = they support combustion > Helium = low solubility and high gas embolism

CO2 is a peritoneal/diaphragm irritant that can cause

Postoperative shoulder pain

____ anesthesia is the most commonly used technique for diagnostic and laparoscopy surgery.

General anesthesia -Good control of ventilation and patient comfort -Good control for position changes and pneumoperitoneum

Vent changes while under general anesthesia for lap procedure

-Increased minute ventilation, intraoperative recruitment, pressure control, PEEP usage

T/F: NMB allow for better surgical operating conditions at lower insufflation pressures

FALSE. -This was a hypothesis that has not been seen to be true

T/F: N2O use contributes to bowel distention and increased PONV.

TRUE.

Benefits of regional anesthesia when appropriate:

-Reduction of stress response -Early ambulation with lower DVT risk -Effective postoperative analgesia

Downsides to regional anesthesia:

-May not always be the best due to high sensory levels required. -May be difficult with pneumoperitoneum and proper positioning -High incidence of shoulder pain, not treated by regional techniques

_____ is a major concern for patients that underwent lap procedures.

PONV -As high as 72% of ppl experience PONV -Can cause dehiscence, aspiration, prolonged hospital stay

Standard of care for PONV treatment

Multimodal *Always choose this if you see it as a choice* -Avoid N2O if possible

Postoperative pain control methods

Multimodal -ERAS -NDSAIDs -Glucocorticoids -Local blocks