Anaesthesia for Laparoscopy

ByCapt Bilal Baig

Graded AnaesthetistSupervised by

Col Muhammad Boota

Aims

• to underline the principles of anaesthesia for laparoscopic surgery

• to point out the dangers of peritoneal insufflation of CO2 and look at alternatives

Objectives

• to increase awareness of the risks and benefits of laparoscopic surgery from the anaesthetist’s (and patient’s) point of view

• to stimulate further interest and research in newer techniques which may reduce the risks

Introduction

• Gynaecological laparoscopy

• Dangers of peritoneal insufflation of CO2“Though laparoscopy offers advantages to both patients and

surgeon it involves considerable alteration in respiratory and cardiovascular homeostasis and should not be

regarded as yet another minor investigation”

Hodgson, McClelland and Newton 1970

Problems

• cardiopulmonary effect of pneumoperitoneum

• systemic carbon dioxide absorption

• extraperitoneal gas insufflation

• venous gas embolism

• unintentional injuries to intra-abdominal structures and patient positioning

Anesthetic management

Anaesthetic Goals

• Accommodate surgical requirements and allow for

physiological changes during surgery.

• Monitoring devices available for the early detection of

complications.

• Recovery from anaesthesia should be rapid with minimal

residual effects.

• The possibility of the procedures being converted to open

laparotomy to be considered

Pre-anaesthetic assessment

• Contraindications to laparoscopic surgery are relative

• The cardiac and pulmonary status of all patients should be carefully assessed

• Premedication is usually not necessary except in anxious patients

• Atropine can be used for premedication to prevent vagally mediated bradyarrhythmias 

Monitoring Recommendations for routine patient monitoring include• Pulse rate • Continuous ECG • Intermittent NIBP • Pulse oximetry (SpO2) • Capnography (EtCO2) • Temperature • Intraabdominal pressure • Pulmonary airway pressure

Optional Monitoring includes• Oesophageal stethoscope • Precordial doppler • Transoesophageal echocardiography

Anaesthetic techniques

The choice of anaesthetic technique

• General anaesthesia • muscle paralysis,

• tracheal intubation

• intermittent positive pressure ventilation (IPPV) .

• At induction of anaesthesia it is important to avoid stomach inflation during ventilation

• The use of nitrous oxide during laparoscopic surgery is controversial because of concerns about its ability to produce bowel distension during surgery and the increase in postoperative nausea .

• Halothane increases the incidence of arrhythmia during laparoscopic surgery, especially in the presence of hypercarbia 

Anaesthetic techniques

• Regional anaesthesia – Epidural anaesthesia for outpatient gynaecological

laparoscopic procedures to reduce complications and shorten recovery time after anaesthesia .

– not been reported for laparoscopic cholecystectomy or other upper abdominal surgical procedures except in patients with cystic fibrosis .

– The high block produces myocardial depression and reduction in venous return, aggravating the haemodynamic effects of tension pneumoperitoneum

Patient positioning

The Trendelenburg position

• temporarily in upper abdominal surgery for trocar insertion • retained for longer periods in lower abdominal surgery • increases the venous return (VR), the right atrial pressure

(RAP), the central blood volume and the cardiac output • right main stem bronchial intubation and hypoxaemia • Nerve compression and Brachial plexus injury • elevation of the intracranial and intraocular pressure

Patient positioning

The reverse Trendelenburg position

• improves diaphragmatic function and is considered more favourable to respiration

• decreased venous return (VR), right atrial pressure (RAP) and pulmonary capillary wedge pressure (PCWP)

• fall in the mean arterial blood pressure (MAP) and cardiac output (CO)

• may be disastrous in patients with coronary insufficiency • steep head-up position causes venous stasis in the legs

predisposing to deep vein thrombosis

Insufflation of exogenous gas,CO2

• CO2 has remained the insufflation gas of choice – ready availability – low cost– a high Ostwald's blood/gas partition coefficient (0.48) – odourless– relatively inert – non-combustible – rapidly buffered in the blood by bicarbonates and excreted via the lungs

• The CO2 absorption is more following extraperitoneal rather than intraperitoneal insufflation

• Mild hypercapnia causes sympathetic stimulation which results in tachycardia, increased systemic vascular resistance, systemic arterial pressure, central venous pressure and cardiac output

Physiological effects

• Depends on– patient's preexisting cardiopulmonary status– the anesthetic technique – intra-abdominal pressure (IAP)– carbon dioxide (CO2) absorption– patient position – duration of the surgical procedure

Physiological effects

Cardiovascular

• increase in systemic vascular resistance, mean arterial

pressure, and cardiac filling pressures

• more severe in patients with preexisting disease

• significant changes occurring at pressures greater than 12

mmHg

• increased cerebral blood flow and intracranial pressure,

• decreased total hepatic blood flow

Physiological effects

Cardiovascular• reduced bowel circulation resulting in

decreased gastric intramucosal pH • reduction in renal blood flow and urine

output • decreased femoral vein blood flow which

may increase the risk of deep vein thrombosis.

Physiological effects

Pulmonary changes

• increased IAP displaces the diaphragm upward • functional residual capacity and total lung

compliance decreases• basal atelectasis and increased airway pressures• increase in minute ventilation required to maintain

normocarbia • exaggerated in obese patients and in those with

respiratory dysfunction.

Complications of gas insufflation

• Subcutaneous emphysema

– occur if the tip of the Veress needle does not penetrate the peritoneal cavity prior to insufflation of gas.

– Extraperitoneal insufflation, which is associated with higher levels of CO2 absorption than intraperitoneal insufflation, is reflected by a sudden rise in the EtCO2, excessive changes in airway pressure and respiratory acidosis

Complications of gas insufflation

• Pneumothorax, Pneumomediastinum and Pneumopericardium – Sudden hypoxia, rise in peak airway pressure,

hypercarbia, haemodynamic alterations and abnormal movement of the hemidiaphragm on laparoscopic view should raise a suspicion of pneumothorax.

Complications of gas insufflation

• Venous gas embolism – Although a rare complication, it can be potentially fatal

– Slow infusion of gas absorbed across the pulmonary capillary alveolar membrane is shown by rising pulse rate, systolic hypertension, increased oozing and rising EtCO2 inspite of hyperventilation

– At high infusion rates, gas bubbles may lodge in the smaller pulmonary vessels or may lock the pulmonary outflow tract with catastrophic results

Postoperative morbidity

Postoperative Pain

• Patients often complain of abdominal and shoulder tip pain after laparoscopic surgery

• Complete removal of the insufflating gas is essential on completion of the procedure

• Infiltration of the portal sites with a local anaesthetic reduces pain from the port sites while right-sided subdiaphragmatic instillation with a local anaesthetic reduces shoulder tip pain

Postoperative morbidity

Post Operative Nausea & Vomiting (PONV)

• Peritoneal insufflation, bowel manipulation and pelvic surgery are some of the causative factors

• A meticulous anaesthetic technique along with antiemetics is helpful in reducing the incidence of PONV

Pathophysiological effects

Respiratory: Hypercapnoea

• Head down, spontaneous respiration

• CO2 absorption

• Compromised diaphragm function with

raised IAP

• Pneumothorax

Pathophysiological effects CO2 pneumoperitoneum (Safran and Orlando AJS 1994)

• Hypertension, tachycardia leading to increased myocardial oxygen demand

• Increased noradrenaline levels leads to increased SVR (and decreased Q)

• Hypercarbia and acidosis

• Decrease in urine output and increased plasma renin activity (PRA)

– due to increased intra-abdominal pressure (IAP) and the local compression of renal

vessels

• Intra-abdominal distension leads to a decrease in pulmonary dynamic compliance .

• Low compliance, together with an increased minute volume of ventilation, is

accompanied by high peak airway pressures .

• head-up positioning and fluid deficit accounts for many of the adverse effects in haemodynamics during laparoscopic cholecystectomy (Hirvonen et al 2000).

Studies of laparoscopic vs open procedures

• endocrine and metabolic changes during acute emergency abdominal surgery performed using either laparoscopy or laparotomy in children. Prolactin, cortisol, interleukin-6, glucose, insulin, lactic acid and epinephrine levels .. No differences were elicited (Bozkurt et al. 2000)

• stress responses after sigmoid colectomy, in patients undergoing lap. assisted colectomy, are comparable with open operation (Fukushima et al. 1996)

• LC produces significant increases in stress hormone levels … “not physiologically minimally

invasive”. (Naude et al. 1997)

Studies of laparoscopic vs open procedures

• significant lower values of intraoperatively and postoperatively measured epinephrine, norepinephrine, interleukin-1 beta, and interleukin-6 in patients with laparoscopic vs open cholecystectomy (Glaser et al. 1995)

• neuroendocrine stress response and inflammatory response following laparoscopic cholecystectomy were significantly reduced compared with those after open cholecystectomy (Karayiannakis et al. 1997)

• activation of stress-related factors during gynaecologic laparoscopy seems to be less intense and of shorter duration (Muzii et al. 1996)

Studies of laparoscopic vs open procedures

Conclusion

More studies and larger patient groups are needed to be certain that laparoscopic

procedures produce less stress response than open procedures … especially if the

duration of the operation is longer

Conclusion

Laparoscopy has revolutionised surgery and in the process influenced the practice of anaesthesiology.

With patient expectation of no pain or nausea and early discharge, anaesthetic choices become vital for the ultimate success of the procedure