Anesthesia for Laparoscopic Interventions

Peter BiroDepartment of AnesthesiologyUniversity Hospital Zurichpeter.biro@usz.ch

The „Good“

Advantages

Better cosmetic results Less pain, less analgesics required Shorter in-hospital stay Less complications (outcome?) Better pulmonary function (in particular in obese patients) Fast recovery, better comfort

Cholecystectomies in my Hospital

1990 1991 1992 1993 1994 1995 1996 1997 2001 20020

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Open Laparoscopic

Cholecystectomies in my Hospital

1990 1991 1992 1993 1994 1995 1996 1997 2001 20020

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60

90

120

150

180

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240

Open Laparoscopic

Open portion

50%

Cholecystectomies in my Hospital

1990 1991 1992 1993 1994 1995 1996 1997 2001 20020

30

60

90

120

150

180

210

240

Open Laparoscopic

Open portion

33%

Cholecystectomies in my Hospital

1990 1991 1992 1993 1994 1995 1996 1997 2001 20020

30

60

90

120

150

180

210

240

Open Laparoscopic

Open portion

13%

Surgeon Urologist Gynecologist

DiagnosticIntestinal

HerniotomyLiver

SpleenFundioplication

CholecystectomyEsophagus

Axillar lymphonodesGastric bandingAdrenalectomy

Parathyreoidectomy

DiagnosticNephrectomyKidney cysts

ProstatectomyVaricocele

LymphadenectomyTesticular descensus

DiagnosticTubar ligationAdnexectomyOvarectomy

LymphadenectomyEndometriosisMyomectomy

Axillar lymphonodes

What about the Anesthetist?

General Anesthesia&

Perioperative maintenanceof vital functions

...and comfort

The „Bad“

Mechanical Effects of Pneumoperitoneum

Elevated intra- and retroperitoneal pressure Diaphragma displacement to cranial Elevated intrathoracic pressure Increase of airway pressure Decrease of total respiratory compliance Gas embolism (risk of)

Effects on Pulmonary Function

Change of FEV1 (post- vs. preoperative) ―55% ―30% Duration till return to baseline FEV1 9.5 days 5 days FRC on 1st postoperative day ―20% ―34% PEF25-75% on 2nd postoperative day ―50% ―25% Confirmed post operative atelectasis (X-ray) ―90% ―40%

Open vs. LaparoscopicCholecystectomy

Other Effects of Pneumoperitoneum

Resorption of CO2 (hypercarbia, acidosis) Increase of PCO2 (arterial and end-tidal) Acidosis Increase of lactic acid Hormonal changes (catecholamines, vasopressin) Aggravation or improvement of side effects due to posture

...but oxygenation remains basically unchanged

Hemodynamic Effects of Pneumoperitoneum

Increase of atrial filling pressures (right: CVP, left: wedge pressure) Increase of heart rate Increase of both, systemic and pulmonary vascular resistance Increase of both, arterial and pulmonary blood pressure Cardiac output and intrathoracic blood volume show unconsistent changes in both

directions

Hormonal Effects of Pneumoperitoneum

Increase of... Vasopressine Dopamine Adrenaline Noradrenaline Renine Cortisone

► sympatho-adrenergical stimulation, „stress“ metabolism

Example for Overlaping Effects

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MAP HR SVR

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120 Baseline PneumoperitoneummmHgBeats/min

Dyne/s/cm-5/20

CO2 Homeostasis and Pneumoperitoneum

CO2 uptake in 2 phases: Initially fast resorption for app. 30 minutes Followed by equlibration on higher level (>30% of baseline)

If spontaneous ventilation possible ►increase of alveolar ventilation

V/Q mismatch leads to arterio-alveolar CO2 difference.

► invasive blood gas measurements mandatory in high risk patients (>ASA III)

Patients at Cardial Risk

Due to... acute elevated afterload and sometimes decreased preload (head up posture)

► one must aplly: invasive arterial blood pressure measurement In case of cardial insufficiency / pulmonary hypertension: TEE, Swann-Ganz

catheter IAP not above 10 mmHg or even better

...arrangement for or transition to

open surgical procedurein neutral horizontal position

Patients at Cardial Risk

Measures to improve situation (before transition to open surgical approach)... Reduction of afterload with vasodilators Carefull fluid replacement (under continuous TEE controll) Application of positive inotropic and vasodilating agents such as

dobutamine or phosphodiesterase inhibitors

Immediate measures in case of dramatic cardial deterioration: reversal of pneumoperitoneum (stop CO2 inflow, deflate abdomen) reversal of head down position to neutral or slightly elevated

Organ Perfusion and Pneumoperitoneum

Decrease of... gastrointestinal blood flow (in particular with IAP > 15 mmHg) renal blood flow

Increase of... cerebral blood flow (cave: patients with elevated intracranial pressure)

Pneumoperitoneum and Pregnancy

Increase of intrauterine pressure Decrease of uterine blood flow Decrease of fetal blood pressure

Consequences have to be evaluated on an individuall scale. Eventually consideration of

open surgical procedurein neutral horizontal position

Pneumoperitoneum and Pregnancy

Cholecystectomy is the most often perfomed non-obstetric surgical intervention in pregnancy

Meanwhile 50% are performed in laparoscopic mode However,...

surgery before 20th week of gestation bears elevated risk for preterm birth No evidence for difference in malformation frequency in open vs.

laparoscopic surgery

Actually there is no general contraindication for

laparoscopic surgeryin pregnancy

Pediatric Surgery

Since the nineties laparoscopy usual for neonates and toddlers

Hemodynamic effects are more pronounced

►Therefore... ► limit IAP to < 8 mmHg ► table positioning angle not exceeding ±15° ► avoid vagal reflexe (bradycardia) ► not recommended for emergency operations

Morbid Obesity

Higher rate of complications (+18%) Longer in-hospital stay (4-5 days more)

However, laparoscopic procedures have strong advantages... less problems with wound healing less tendency for burst abdomen early mobilization

CO2 Homeostasis and Pneumoperitoneum

Amount of CO2 uptake is dependent on intraabdominal pressure (IAP) and duration of pneumoperitoneum

With IAP < 10 mmHg hyperkapnia is unlikely After discontinuation of pneumoperitoneum fast reversal of

hypercarbia even without forced hyperventilation

Complications

Aspiration of gastric content Intraoperative occurrence up to 6% in 50% of cases reflux of gastric acid

Consequences ► gastric tubing ► tracheal intubation (no laryngeal mask or similar supraglottic devices)

Complications

Secondary unilateral bronchial ETT displacement Etiology

diaphragma elevation airway shifts upwards while ETT is fixed at teeth level

Consequences ► ETT advancement not deeper than 20 cm ► carefull checking and ►re-checking of bilateral ventilation (in case of

doubt fiberbronchoscopy)

Complications

Hypothermia not less than in open surgery ► use patient warming devices as usual

Smoke resorption carbon monoxide (CO) poisoning possible ►check blood gases regularly

Surgical emphysema due to improper CO2 insuflation ►check for airway obstruction

Vascular injury and bleeding may occurr during insertion of scope ►avoidance by muscular relaxation

Complications

Pneumothorax ► stop CO2 inflow, ► deflate abdomen, ► insert thoracic drainage

Pneumomediastinum typical for surgery of diaphragma or esophagus differencial diagnosis to pneumothorax or gas embolism necessary risk of pericardial tamponade

► diagnosis to be made with echoecardiography

Complications

Gas (CO2) embolism Etiology

intravasal gas insufflation (CO2 voulme 5x larger than for air) Symptoms

fast decrease of PetCO2

decrease of oxygen saturation (SpO2) without change of airway pressure Hypotension Cardiac arrhytmia Precordial „mill wheel sound“

► Measures stop CO2 inflow, ► deflate abdomen, ► left tilt position, ► aspiration of gas via central

venous line

Side Effects

Postoperative pain positive correlation to level and duration of IAP and intraabdominal pH projection into the shoulder due to irritation of diaphragm sometimes free interval up to 24 hours duration up to 3-4 days

►Therapy

multi modal analgesia (combination of different drugs and application modalities according to standardized protocolls)

Side Effects

Postoperative Nausea and Vomiting (PONV) more in laparoscopic than in open surgery (in particular

gynecology) young females < 30 years non smokers early pregnancy first phase of menstruation amount of CO2 uptake

Therapy

corticoids, 5-HT3 antagonists, dehydrobenzperidol

Schulte Steinberg H., Euchner Wamser I., Zalunardo M.P. Anästhesie für laparoskopische Eingriffe. Anaesthesist 1999, 48: 755-768