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Basic Science  in Basic Science  in Laparoscopic SurgeryLaparoscopic Surgery

ContentsContents

• Pneumoperitoneum

• Patient positioningPatient positioning

• Laparoscopic instrumentation

• Access into the abdomen

Laparoscopic SurgeryLaparoscopic Surgery

• Minimally Invasive Surgery (MIS)

• Keyhole SurgeryKeyhole Surgery

• Pinhole Surgery

ContraindicationContraindication

• Uncorrected coagulopathy

• Inability to tolerate laparotomyInability to tolerate laparotomy

• Inability ti tolerate general anesthesia

• Hypovolemic shock

• Uncompensated cardiopulmonary diseaseUncompensated cardiopulmonary  disease

PneumopeitoneumPneumopeitoneum

Mechanical effect (Primarily)

• 1. Upward displacement of diaphragm1. Upward displacement of diaphragm– ↑ Intrathoracic pressure

↓ Di h i i– ↓  Diaphragmatic motion

– ↓ Lung volume  “↓vital capacity,↓ compliance”

– ↑ Airway pressure“↑ peak ,↑mean airway pressure”

– ↑Work of breathing↑ Work of breathing

PneumopeitoneumPneumopeitoneum

Metabolic effect 

• 1. CO2 absorption1. CO2 absorption– Leads to hypercarbia and acidosis

“I h l h i di id l d b il i d“In healthy individuals: corrected by ventilation and body buffering system”

“In COPD:risk to develop hypercarbia

Expired CO2 (ETCO2) levels are unreliable:Expired CO2 (ETCO2) levels are unreliable:

arterial CO2 needed

HypercarbiaHypercarbia

d i i• Moderate increase in PaCO2 15‐30 mmHg produce a hyperdynamic state:    SVR,  CVP, HR and BP “no effect on CO”

• Marked increase in PaCO2> 30 mmHg: cardio gdepressive  predominate, cardiovascular collapse, severe acidosis, fatal dysrhythmiasp , , y y

• Minute ventilation must be increased 20‐30%

HypercarbiaHypercarbia

• Lowering IAP to 10‐12 mmHg

• Alternative gas : HeliumAlternative gas : Helium

• Gasless laparoscopy

• Converted to open surgery

Pneumoperitoneum $ VentilationPneumoperitoneum $ Ventilation

ETCO2ETCO2

Ventilation changeVentilation change

• 1. High inspiratory airway pressure

• 2. Decrease FRC2. Decrease FRC

• 3. Increase V/Q mismatch

Cardiovascular changeCardiovascular change

I iti ll ↑ t d t th bl d• Initially: ↑ venous return due to the blood volume sequestrated in splanchnic vasculature

“Increase mean arterial pressure”“Increase mean arterial pressure”• Later on: ↓venous return, ↑arterial resistance , ↑ CVP↑ CVP 

“ Resulted in compensatory ↑HR”“N t ff t h i CO”“Net effect     =    no change in CO”

• IAP> 20 mmHg: IVC is compressed then venous return is impededreturn is impeded

• IAP> 40 mm Hg, venous return drop precipitously 

Pneumoperitoneum $ CardiovascularPneumoperitoneum $ Cardiovascular

Patient PositioningPatient Positioning

d d ( d l b i i )• Head‐down (Trendelenburg position)–↑Central blood volume and pressurep–↑Cardiac output↑Chest wall resistance ↑ dead space– ↑Chest wall resistance, ↑ dead space

• Head‐up–↓Venous return & Cardiac output–↑Femoral venous pressure↑Femoral venous pressure–↑risk of DVT or pulmonary embolism

Pneumoperitoneum $ Ventilation$Pneumoperitoneum $ Ventilation$  Positioningg

Pneumoperitoneum $ Cardiovascular $  p $ $Positioning

ArrhythmiaArrhythmia

• Vagal reflex  because of sudden stretching peritoneum with rapid  insufflation p pprovoke AV dissociation, nodal rhythm, sinus bradycardia and asystolesinus bradycardia and asystole

• Raise PaCO2: sympathetic response

• Embolism

• Underlying cardiac disease• Underlying cardiac disease

Renal Blood FlowRenal Blood Flow

• Decreased RBF and GFR Increase in renal vascular resistance, reduction in ,glomerular filtration gradient and decrease in CO

• Decreased urine output and insensible fluid losseslosses

R l Bl d Fl $ P l d $Renal Blood Flow $ Pre‐load $ PneumoperitoneumPneumoperitoneum

Lactic AcidosisLactic Acidosis

• Elevation in IAP produces lactic acidosis, probably by severely lowering CO and p y y y gimpairing hepatic clearance of blood lactic acidacid

Intracranial and Intraoccular changeIntracranial  and Intraoccular change

l l fl f • Increase cerebral blood flow from hypercarbiayp

• But increase intracranial pressure, intraocular pressure in the cases that intraocular pressure in the cases that have underlying diseases

Metabolic Effect of CO2Metabolic Effect of CO2

Increase in PaCO2

1. Absorption of CO2 from the peritoneal cavity1. Absorption of CO2 from the peritoneal cavity2. V/Q mismatch3 I i d CO ti it ( COPD3. Impaired CO2 e x cretion capacity (e.g., COPD, 

cyanotic CHD)

CO2 EmboliCO2 Emboli

• Presenting signs– Hypotensionyp

– Jugular vein distension

– TachycardiaTachycardia

– Mill Wheel Murmur

CO2 EmboliCO2 Emboli

E l ( 0 5 l/k f b li)• Early (< 0.5ml/kg of emboli):– TEE CO2 bubbling in right heart 

l hi d i h di l d l– splashing sound with precordial doppler– millwheel murmur 

h i hi h i i P CO2– hypoxemia, high increasing PaCO2, – high ΔPaCO2‐ETCO2L ( 2 l/k f b li)• Late (>2ml/kg of emboli):– increase CVP, PAP 

h i h h i– hypotension, arrhythmia– cardiac arrest

CO2 EmboliCO2 Emboli

CO2 EmboliCO2 Emboli

• Treatment– Evacuate pneumoperitoneump p

– Left lateral decubitus , head down position

Introduce central venous catheter– Introduce central venous catheter

Laparoscopic EquipmentLaparoscopic Equipment

• Laparoscopes

• Video TowerVideo Tower

• Gas Supply

• Suction Device

• Equipment TableEquipment Table

LaparoscopesLaparoscopes

LaparoscopesLaparoscopes

• Deliver light from a light source

• Conduct image to eyepieceConduct image to eyepiece

LaparoscopesLaparoscopes

Video TowerVideo Tower

Light source

Light cable

Imaging systemsImaging systems

• Camera Head Unit

• Camera Control Unit

Gas SupplyGas Supply

• Gas tank

• GasGas– CO2

R dil il bl• Readily available

• Ine x pensive

N b i• Not support combustion

– N2O

– Helium

InsufflatorInsufflator

Control the flow of gas– Control the flow of gas from the cylinder to the abdomenthe abdomen

– High flow insufflatord lcan deliver 10 or more 

liters of gas per mintued dand rate can adjust 

from low to high

InsufflatorInsufflator

• Control panel– Indication system listing y gthe preset abdominal pressurep

– The current abdominal pressurepressure

– The flow rate of the gas

A f d– Amount of gas used

Gas SupplyGas Supply• A sterile line takes gas from the sufflatorA sterile line takes gas from the sufflatorto the patient  (Luer lock or push on tube

S li h filt i l• Some line have a filter in place

Suction DevicesSuction Devices

• Multiple suction devices are needed– Anesthesiologistg

– Nasogastric tube

Laparoscopic instruments– Laparoscopic instruments

Video TowerVideo Tower

• Video monitor

FORMATSFORMATS

ResolutionResolution

640640

1280

1920

DefinitionDefinition

Full HDFull HD

Full HDFull HD

Full HDFull HD

• 16:9 ratio for natural vision

• 16:9 ratio provides lateral ex tension of field of16:9 ratio provides lateral ex tension of field of vision

G l b illi• Great color brilliance

• 1920 x 1080 offers 7 times the SD resolution at 480 lines

Cl diff ti ti f ti t t• Clear differentiation of tissue structures

Impeded viewImpeded view

Pressure Flow Cause

Low High LeakLow High

Low Low

Leak

Empty

High Low

High High

Rela x ation/ Occlusion

Multifactorial/ mulfunction

Energy SourceEnergy Source

• Electrosurgery– Monopolar cauteryp y

– Bipolar cautery

Ult i• Ultrasonic

Injury from Energy SourceInjury from Energy Source

• Direct Coupling

Injury from Energy SourceInjury from Energy Source

• Indirect Coupling

Ultrasonic CoagulationUltrasonic Coagulation

• Relies on mechanical energy to produce effects

Operating Room Set upOperating Room Set‐up

• Patient positioning

• Video‐endoscopic equipmentVideo endoscopic equipment

• Ancillary equipment

• Personnel

Patient PositioningPatient Positioning

• Supine

• Lateral DecubitusLateral Decubitus

• Lithotomy

SupineSupine

• Arms out– Upper abdomenpp

– Incisional hernia

SupineSupine

• Tucking arms– Pelvis and lower abdomen

Patient PositioningPatient Positioning

• Tendelenberg

• Reverse TendelenbergReverse  Tendelenberg

DVT PreventionDVT Prevention

PersonnelPersonnel

PersonnelPersonnel

Primary AccessPrimary Access

• Open 

“Hasson”Hasson

Primary AccessPrimary Access

• Direct vision

Primary AccessPrimary Access

• Veress Needle

Direct vs Veress (RCT)Direct vs Veress (RCT)

Current Laparoscopic SurgeryCurrent Laparoscopic Surgery

• LC

• CBD exploration• Adrenalectomy

• TraumaCBD exploration

• Anti‐reflux surgery• Trauma

• Large and small bowel• Achalasia

• Hernia (inguinal ventral)• Appendectomy

• Gastric surgeryHernia (inguinal, ventral)

• Peptic ulcer operation• Gastric surgery

• Morbid obesity• Splenectomy • (endoscopic thyroid Sx)

ConclusionConclusion

ConclusionConclusion