Anaesthesia for laparoscopic surgery - PowerPoint Presentation

Slide1

Anaesthesia for laparoscopic surgery

Presented by:

Rashmi

Bhatt

Moderator: Prof

Surinder

SinghSlide2

objectives

Laparoscopic surgery : risk

vs

benefits

Laparoscopic

vs

open surgery

Anaesthetic

implications: respiratory,

ventilatory

and

haemodynamic

alterations.

Pre operative assessment

Intraoperative

management:

anaesthetic

techniques, monitoring, complications (diagnosis and management)

Post operative considerationsSlide3

Laparoscopic surfgery

Surgical procedures have been improved to reduce trauma to the patient, morbidity, mortality, and hospital stay, with consequent reductions in health care

costs.

Starting in the early 1970s, various pathologic

gynecologic

conditions were diagnosed and treated using laparoscopy. This endoscopic approach was extended to

cholecystectomy

in the late

1980s.

laparoscopy results in multiple benefits compared with open procedures

and

was characterized by better maintenance of

homeostasis which

explains the effort to use the laparoscopic approach for gastrointestinal (e.g., colonic, gastric,

splenic

, hepatic surgery),

gynecologic

(e.g., hysterectomy), urologic (e.g.,

nephrectomy

, prostatectomy), and vascular (e.g., aortic)

procedures.Slide4

Ventilatory changes

The

pneumoperitoneum

and the patient positions required for laparoscopy induce

pathophysiologic

changes that complicate

anesthetic

management.

Pneumoperitoneum

decreases

thoracopulmonary

compliance by 30% to

50%. Reduction

in functional residual

capacity

and

development of

atelectasis

due to elevation of the

diaphragm

and

changes in the distribution of pulmonary ventilation and perfusion from increased airway pressure can be

expected.

However

, increasing IAP to 14 mm Hg with the patient in a 10- to 20-degree head-up or head-down position does not significantly modify either physiologic dead space or shunt in patients without cardiovascular

problems.

the partial pressure of arterial carbon dioxide (Pa

co

2

) progressively increases to reach a plateau 15 to 30 minutes after the beginning of CO

2

insufflation

.Slide5

Any significant increase in Pa

co

2

after this period requires a search for a cause independent of or related to CO

2

insufflation

, such as CO

2

subcutaneous emphysema. The increase in Pa

co

2

depends on the

IAP.

During

laparoscopy with local

anesthesia

, Pa

co

2

remains unchanged but minute ventilation significantly increases

.

mean gradients (Δa-ETCO

2

) between Pa

co

2

and the end-tidal carbon dioxide tension (P

etco

2

) do not change significantly during peritoneal

insufflation

of

CO

2.

the lack of correlation between Pa

co

2

and P

etco

2

in sick patients, particularly those with impaired CO

2

excretion

capacity.

Consequently,

hypercapnia

can develop, even in the absence of abnormal

P

etco

2

.

Postoperative

intra-abdominal CO

2

retention results in increased respiratory rate and P

etco

2

of patients breathing spontaneously after laparoscopic

cholecystectomy

as compared with open

cholecystectomy

.Slide6

the increase of Pa

co

2

may be

multifactorial

: absorption of CO

2

from the peritoneal cavity, impairment of pulmonary ventilation and perfusion by mechanical factors such as abdominal

distention

, patient position, and volume-controlled mechanical

ventilation, the main mechanism being absorption of CO

2.

absorption of a gas from the peritoneal cavity depends on its

diffusibility

, the absorption area, and the perfusion of the walls of that cavity. Because CO

2

diffusibility

is high, absorption of large quantities of CO

2

into the blood and the subsequent marked increases in Pa

co

2

would be expected to occur. The limited rise of Pa

co

2

actually observed can be explained by the capacity of the body to store

CO

2

and by impaired local perfusion due to increased

IAP.Slide7

Respiratory changes during the laparoscopic procedure may contribute to increasing CO

2

tension. Mismatched ventilation and pulmonary perfusion can result from the position of the patient and from the increased airway pressures associated with abdominal

distention

.

At higher IAPs, the continued rise of Pa

co

2

without a corresponding increase in results from an increase in respiratory dead

space.

If controlled ventilation is not adjusted in response to the increased dead space, alveolar ventilation will decrease and Pa

co

2

will

rise.

Pa

co

2

should be maintained

within a physiologic range by adjusting the mechanical ventilation. Except in special circumstances, such as when CO

2

subcutaneous emphysema

occurs,

correction of increased Pa

co

2

can be easily achieved by a 10% to 25% increase in alveolar

ventilation.Slide8

Haemodynamic changes

Multifactorial

:

result from the combined effects of

pneumoperitoneum

, patient position,

anesthesia

, and

hypercapnia

from the absorbed

CO

2

,

reflex increases of

vagal

tone and

arrhythmias.

IN HEALTHY PATIENTS:

IAP

higher than 10 mm Hg induces significant alterations of

hemodynamics

. Results in decrease

in cardiac

output (10 to 30%),

increased arterial pressures, and elevation of systemic and pulmonary vascular

resistances.

Heart

rates remain unchanged or increased only slightly. The decrease in cardiac output is proportional to the increase in IAP

.

Cardiac output has also been reported to be

increased

or unchanged during

pneumoperitoneum

.

changes in cardiac output

are

well tolerated by healthy patients.

Cardiac

outputs, which decrease shortly after the beginning of the peritoneal

insufflation

, subsequently increase, probably as a result of surgical stress.

Slide9

mechanism of the decrease of cardiac output is

multifactorial

:

dec

venous return (

venacaval

compression

,

pooling of blood in the legs

,

and an increase in venous

resistance)

reduction in left ventricular end-diastolic

volume

Cardiac filling

pressures rise

during peritoneal

insufflation

due to

increased

intrathoracic

pressure.

Right

atrial

pressure and pulmonary artery occlusion pressure

not reliable

indices of cardiac filling pressures during

pneumoperitoneum

.

Increased filling pressures can be achieved by fluid loading or tilting the patient to a slight head-down position before peritoneal

insufflation

, by preventing the pooling of blood with intermittent sequential pneumatic compression

device,or

by wrapping the legs with elastic bandages

.Slide10

increase in systemic vascular resistance during the existence of the

pneumoperitoneum

.

not

a reflex sympathetic response to the decreased cardiac output.

Although

the normal heart tolerates increases in

afterload

under physiologic

conditions,can

be deleterious to patients with cardiac disease

.

The

Trendelenburg

position attenuates this

increase in SVR,

the head-up position aggravates it.

The

increase in systemic vascular resistance can be corrected by the administration of

vasodilating

anesthetic

agents, such as

isoflurane

,

or

direct

vasodilating

drugs, such as

nitroglycerin

or

nicardipine

.

mediated by mechanical and

neurohumoral

factors.

Catecholamines

, the

renin-angiotensin

system, and especially

vasopressin contribute

to increasing the

afterload

. Slide11

Increases in plasma vasopressin concentrations correlate with changes in

intrathoracic

pressure and

transmural

right

atrial

pressure. Mechanical stimulation of peritoneal receptors also results in increased vasopressin release,

systemic vascular resistance, and arterial pressure.

The

increase in

SVR

also explains why the arterial pressure increases but the cardiac output falls.

α

2

-adrenergic

agonists such as

clonidine

or

dexmedetomidine

and of β-blocking

agents

significantly reduces hemodynamic changes and

anesthetic

requirements. Use of high doses of

remifentanil

almost completely prevents the hemodynamic

changes.

Increased IAP and the head-up position result in lower limb venous stasis

.

may predispose to the development of

thromboembolic

complications.

Urine output, renal plasma flow, and

glomerular

filtration rate decrease to less than 50% of baseline values during laparoscopic

cholecystectomy

.Slide12

IN HIGH RISK CARDIAC PATIENTS:

In patients with mild to severe cardiac disease, the pattern of change

in

haemodynamic

parameters

is qualitatively similar to that in healthy

patients but Quantitatively

, these changes

are

more

marked.

IV

nitroglycerin

,

nicardipine

, or

dobutamine

has been used

in selected

patients with heart disease.

Nitroglycerin

was chosen to correct the reduction in cardiac output associated with increased pulmonary capillary occlusion pressures and systemic vascular resistance.

nicardipine

may be more appropriate than

nitroglycerin

as it

acts selectively on arterial resistance vessels and does not compromise venous

return.This

drug is beneficial in case of congestive heart

failure which

can develop in the early postoperative

period

Because

normalization of hemodynamic variables does not occur for at least 1 hour

postoperatively.Slide13

CARDIAC ARRHYTHMIAS DURING LAPAROSCOPY

:

The increased Pa

co

2

may not be the cause of the arrhythmias occurring during laparoscopy. Arrhythmias do not correlate with the level of the Pa

co

2

and may develop early during

insufflation

, when high Pa

co

2

is not present.

Reflex increases of

vagal

tone may result from sudden stretching of the peritoneum and during

electrocoagulation

of the fallopian tubes

.

Bradycardia

, cardiac arrhythmias, and

asystole

can develop.

Vagal

stimulation is accentuated if the level of

anesthesia

is too superficial or if the patient is taking β-blocking drugs.

Treatment consists of interruption of

insufflation

, atropine administration, and deepening of

anesthesia

.

arrhythmias

may also reflect intolerance of

the hemodynamic

disturbances in patients with known or latent cardiac disease. Gas embolism can also result in cardiac

arrhythmias.Slide14

Problems due to positioning

the head-down position results in an increase in central venous pressure and cardiac output. The

baroreceptor

reflex

consists of systemic

vasodilation

and

bradycardia

.

elevation

of the intraocular venous pressure

can

worsen acute

glaucoma.

Although the intravascular pressure increases in the upper torso, the head-down position decreases

transmural

pressures in the pelvic viscera, reducing blood loss but increasing the risk of gas

embolism.

With

the head-up position, a decrease in cardiac output and mean arterial pressure results from the reduction in venous return.

This compounds

the hemodynamic changes induced by

pneumoperitoneum

. The steeper the tilt, the greater the fall in cardiac

output.

The

head-down position facilitates the development of

atelectasis

. Steep head-down tilt results in decreases in the functional residual capacity, the total lung volume, and the pulmonary compliance. These changes are more marked in obese, elderly, and debilitated

patients.Slide15

Post operative benefits

the laparoscopic approach allows for a reduction of the acute phase reaction seen after open

cholecystectomy

.

The metabolic response

is

also reduced after

laparoscopy.

It avoids

prolonged exposure and manipulation of the intestines and decreases the need for peritoneal incision and trauma. Consequently, postoperative

ileus

and fasting, duration of intravenous infusion, and hospital stay are significantly reduced after

laparoscopy.

Laparoscopy allows a significant reduction in postoperative pain and analgesic

consumption.

after

laparotomy

, patients complain more of parietal pain

,

whereas after laparoscopic

cholecystectomy

, patients report also visceral

pain,

pelvic spasm

,

and shoulder-tip pain resulting from diaphragmatic

irritation.

Residual CO

2

pneumoperitoneum

contributes to postoperative

pain.

Benefits of

intraperitoneal

local

anesthetic

are greater after

gynecologic

laparoscopy.

Preoperative administration of

nonsteroidal

anti-inflammatory drugs (NSAIDs) and of cyclooxygenase-2 inhibitors decreases

pain.

Dexamethasone

is also effective in reducing postoperative pain.Slide16

Respiratory dysfunction is less severe and recovery is quicker after

laparoscopy but diaphragmatic

function remains significantly impaired after

laparoscopy.

Thoracic

epidural analgesia does not improve lung function after laparoscopic

cholecystectomy

.

Postoperative pulmonary function of these patients, however, is improved after laparoscopy as compared with

laparotomy

.

postoperative nausea and vomiting (PONV) (40% to 75% of patients).

Whereas

perioperative

opioids

increase the incidence of PONV,

propofol

anesthesia

can markedly reduce the high incidence of these side

effects.

Intraoperative

drainage of gastric contents also reduces

PONV.

Intraoperative

administration of

droperidol

and a 5-hydroxytryptamine type 3 antagonist appears to be helpful in the prevention and treatment of these side effects.

Transdermal

scopolamine reduces nausea and vomiting after outpatient

laparoscopy.

Perioperative

liberal intravenous fluid therapy can contribute to decreasing these symptoms and to improve postoperative

recovery.Slide17

Alternatives to CO2

Pneumoperitoneum

Insufflation

of inert gas (e.g., helium, argon) instead of CO

2

avoids the increase in Pa

co

2

from

absorption

so

hyperventilation is not required.

Also, the

ventilatory

consequences of the increased IAP persist. The hemodynamic changes

are

similar to those observed with CO

2

. However, the use of these gases accentuates the decrease in cardiac output, whereas the increase in arterial pressure is attenuated.

Unfortunately

, the low blood solubility of the inert gases raises the issue of safety in the event of gas embolism.

Another alternative is gasless laparoscopy. The peritoneal cavity is expanded using abdominal wall lift obtained with a fan retractor. This technique avoids the hemodynamic and respiratory repercussions of increased IAP and the consequences of the use of CO

2

.

gasless laparoscopy compromises surgical exposure and increases technical difficultySlide18

complications

CO

2

Subcutaneous

Emphysema:

can develop as a complication of accidental

extraperitoneal

insufflation

but can also

an

unavoidable side effect of

certain

procedures that require intentional

extraperitoneal

insufflation

, such as inguinal hernia repair, renal surgery, and pelvic

lymphadenectomy

.

Any increase in P

etco

2

occurring after P

etco

2

has

plateaued

should suggest this complication

.

prevention of

hypercapnia

by adjustment of ventilation becomes almost

impossible.

laparoscopy

must be temporarily interrupted to allow CO

2

elimination and can be resumed after correction of

hypercapnia

using a lower

insufflation

pressure.CO

2

pressure determines the extent of the emphysema and the magnitude of CO

2

absorption.

patient

may be mechanically

ventilated until

hypercapnia

is corrected, particularly in COPD patients, to avoid an excessive increase in the work of breathing. Slide19

Pneumothorax

,

Pneumomediastinum

,

Pneumopericardium

:

Embryonic remnants constitute potential channels of communication between the peritoneal cavity and the pleural and pericardial sacs, which can open when

intraperitoneal

pressure increases. Defects in the diaphragm or weak points in the aortic and

esophageal

hiatus may allow gas passage into the thorax.

Pneumothoraces

may also develop secondary to pleural tears during laparoscopic surgical procedures at the level of the

gastroesophageal

junction.

Capnothorax

(CO

2

causing a

pneumothorax

) reduces

thoracopulmonary

compliance and increases airway

pressures.

absorption from the pleural cavity is greater than from the peritoneal

cavity; Pa

co

2

and P

etco

2

also

increase.

spontaneous resolution of the

pneumothorax

occurs within 30 to 60 minutes without

thoracocentesis

.

When

capnothorax

develops during laparoscopy, treatment with positive end-expiratory pressure (PEEP) is an alternative to chest tube

placement, but if

the

pneumothorax

is secondary to rupture of

preexisting

bullae

, PEEP must not be applied and

thoracocentesis

is mandatory.Slide20

Endobronchial

Intubation:

Cephalad

displacement of the diaphragm during

pneumoperitoneum

results in

cephalad

movement of the carina

potentially

leading to an

endobronchial

intubation. Generally occurs during

procedures in the head-down

position

and

in the head-up

position.

results in a decrease in the oxygen saturation

with an

increase in plateau airway

pressure.

Risk of Aspiration of Gastric

Contents: Patients

undergoing laparoscopy might be considered to be at risk for acid aspiration syndrome

.

However, the increased IAP results in changes of the lower

esophageal

sphincter that allow maintenance of the pressure gradient across the

gastroesophageal

junction and that may therefore reduce the risk of regurgitation

.

Furthermore, the head-down position should help to prevent any regurgitated fluid from entering the

airway, provided airway is secured or airway reflexes are not

obtunded

.Slide21

Gas

Embolism:

most feared and dangerous complication of laparoscopy. Intravascular injection of gas may follow direct needle or

trocar

placement into a vessel, or it may occur as a consequence of gas

insufflation

into an abdominal organ

.

develops principally during the induction of

pneumoperitoneum

,

particularly in patients with previous abdominal

surgery.

CO

2

is used most frequently

as

it is more soluble in

blood.

Rapid elimination also increases the margin of safety in case of intravenous injection of CO

2

. this explains

the rapid reversal of the clinical signs of CO

2

embolism with treatment. Consequently, the lethal dose of

embolized

CO

2

is approximately five times greater than that of air

.

Volume preload diminishes the risk of gas

embolism and

of paradoxical embolism

.

Ventilation-perfusion

mismatching

develops with increases in physiologic dead space and hypoxemia.Slide22

Early events, occurring with 0.5

mL

/kg of air or less, include changes in Doppler sounds and increased mean pulmonary artery

pressure.

When the size of the embolus increases (2

mL

/kg of air), tachycardia, cardiac arrhythmias, hypotension, increased central venous pressure, alteration in heart tones (i.e., millwheel murmur), cyanosis, and

ECG changes

of right-sided heart strain can

develop.

Pulmonary

edema

can also be an early

sign. pulse

oximetry

,

capnometry

and

capnography

are valuable

in providing early diagnosis of gas embolism and determining the extent of the embolism. P

etco

2

decreases in the case of

embolism due to

fall in cardiac output and the enlargement of the physiologic dead

space.

Initially there may be increase in P

etco

2

secondary to pulmonary excretion of the CO

2

, which has been absorbed into the blood

.

Aspiration of gas or foamy blood from a central venous line

is also confirmatory.Slide23

Management: immediate

cessation of

insufflation

and release of the

pneumoperitoneum

. The patient is placed in steep head-down and left lateral

decubitus

(Durant) position

.

Discontinue

N

2

O

to allow

ventilation with 100% O

2

to correct hypoxemia and reduce the size of the gas

embolus.

Hyperventilation

increases CO

2

excretion and

is required for increased

physiologic dead space.

a

central venous or pulmonary artery catheter may be introduced for aspiration of the

gas.

Cardiopulmonary

resuscitation must be initiated if necessary. External cardiac massage may be helpful in fragmenting CO

2

emboli into small

bubbles.

The

high solubility of CO

2

in blood,

results

in rapid absorption from the

bloodstream,and

clinical signs of CO

2

embolism revert rapidly.Slide24

Complications of Laparoscopy

Intestinal injuries

account

for 30% to 50% of these and

remain undiagnosed

during laparoscopy in one half of the cases. Vascular complications also

account

for 30% to 50%. Burns were responsible for 15% to 20% of the reported

complications.

Bowel

perforation,

common bile duct

injury,

and significant

hemorrhage

are seen in lap

cholecystectomy

.

Laparoscopic

cholecystectomy

was accompanied by a greater frequency of minor operative complications, whereas open

cholecystectomy

had a more frequent rate of minor general

complications.

retroperitoneal hematoma can develop insidiously and result in significant blood loss without major

intraperitoneal

effusion, leading to delayed diagnosis. During

gynecologic

laparoscopy, complications occur more frequently during the creation of

pneumoperitoneum

and the introduction of

trocars

, whereas during gastrointestinal surgery they are more closely related to the surgical procedure itself.Slide25

Pre operative evaluation

Pneumoperitoneum

is undesirable in patients with increased intracranial pressure (e.g.,

tumor

, hydrocephalus, head trauma) and

hypovolemia

. Laparoscopy can be performed safely in patients with ventricular peritoneal shunt and

peritoneojugular

shunt that are provided with unidirectional valve resistant to IAPs used during

pneumoperitoneum

.

In patients with heart disease, cardiac function should be evaluated

,

particularly in case of compromised ventricular function

.

Patients with severe congestive heart failure and terminal

valvular

insufficiency are more prone to develop cardiac complications than patients with ischemic cardiac disease during laparoscopy.Slide26

If left ventricular ejection fraction < 30

%: pre op echocardiography.

Intraoperative

monitoring:

Intra-arterial

line,

Pulmonary artery

catheter,Transesophageal

echocardiography, Continuous

ST-segment

analysis. Gasless laparoscopy or

laparotomy

may be considered.

Intraoperative

Management:

Slow

insufflation,Low

intra-abdominal pressure

,Hemodynamic

optimization before

pneumoperitoneum

(preload augmentation) Patient tilt after

insufflation

.

Use of

remifentanil

,

vasodilating

anesthetic

and drugs (

nicardipine

,

nitroglycerin

),

cardiotonic

agents. Preferably an experienced surgeon.

patients with renal failure deserve special care to optimize

hemodynamics

during

pneumoperitoneum

, and the concomitant use of

nephrotoxic

drugs should be

avoided.Slide27

Anaesthetic technique

General

anaesthesia

:

General

anesthesia

with

endotracheal

intubation and controlled ventilation

is

the safest and most commonly used technique and therefore is recommended for inpatients and for long laparoscopic

procedures.

controlled ventilation must be adjusted to maintain P

etco

2

between 35 and 40 mm

Hg;15

% to 25% increase of minute ventilation, except when CO

2

subcutaneous emphysema develops. Increase of respiratory rate rather than of tidal volume may be preferable in patients with COPD and in patients with a history of spontaneous

pneumothorax

or

bullous

emphysema.

The laryngeal mask airway results in fewer cases of sore throat and may be proposed as an alternative to

endotracheal

intubation;

does

not protect the airway from aspiration of gastric contents

.

decreased

thoracopulmonary

compliance during

pneumoperitoneum

frequently results in airway pressures exceeding 20 cm H

2

O. The

ProSeal

laryngeal mask airway may be an alternative to guarantee an airway seal up to 30 cm

H

2

O.

Local and regional anesthesiaSlide28

thankyou