Anaesthesia For Laparoscopy

Anaesthesia for Laparoscopy

Aims • to underline the principles of anaesthesia for laparoscopic surgery • to point out the dangers of peritoneal insufflation of CO2 and look at alternatives • to examine claims that laparoscopic procedures are less stressful than open procedures

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

Anaesthetic techniques

• The role of endotracheal intubation • The role of mechanical ventilation • The role of muscle paralysis • The role of nitrous oxide

Anaesthetic techniques • Capnography – CO2 absorption through peritoneum, venous channels, retroperitoneal and subcutaneous tissues

• Invasive monitoring • Insufflating gas – air, nitrous oxide, carbon dioxide

• Helium – Haemodynamic stability (Fleming et al., Junghans et al. 1997) – Inhibition of tumour growth (Neuhauss et al. 1999)

Pathophysiological effects Haemodynamic • head up versus head down position • bradycardia • blood loss • visceral traction • gas embolus: early versus late

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).

Pathophysiological effects Gasless/abdominal wall lift techniques

• abdominal wall lift permits the conduct of laparoscopic procedures at an intra-abdominal pressure of only 6-8 mm Hg • benefits patients with preexisting cardiac disease and chronic bronchitis, especially for liver surgery (Banting et al. 1993).

Pathophysiological effects Gasless versus CO2 pneumoperitoneum • .. gasless technique provided inferior exposure and the operation took longer, … value in high-risk patients with cardiorespiratory disease? (Vezakis et al. 1999, Johnson and Sibert 1997)

• .. using thoracic epidural: no clinically important differences in cardiovascular and systemic response were observed between patients undergoing CO2 or gasless laparoscopy for colonic disease (Schulze et al. 1999). • .. compromised surgical exposure and thus increased technical difficulty. Patients realised no benefits from its use in terms of postoperative discomfort or return to activity (Goldberg and Maurer 1997) • .. gasless laparoscopic cholecystectomy resulted in more uneventful and faster immediate and late postoperative recovery than conventional carbon

Pathophysiological effects Gasless versus CO2 pneumoperitoneum

Conclusion • Most studies have shown decreased surgical access and increased conversion rates • Cardiorespiratory benefits are limited in most studies • Side effects are similar overall • Need a meta-analysis/more studies

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

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)

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 • Laparoscopic procedures are not minimally invasive physiologically • The benefits of gasless techniques are yet to be established