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Anaesthesia for Laparoscopic Surgery

Padmini Paidhungat
 

Introduction
With the advent of 21st century, the surgeon is turning to endoscopic surgery, which has many advantages and few disadvantages. With laparoscopic surgery as the skin incisions are small with minimal muscle cutting, the postoperative pain is less than open surgery. As the hospital stay is also reduced, the anaesthetic procedure should also be such that the recovery is rapid and allow early ambulation.

Pre-anaesthetic Preparation
Pre-anaesthetic preparation is very important as for any other anaesthesia. Formerly only medically fit patients were accepted for laparoscopic surgery (LS) and this should be the rule for the beginner. However surgeons experienced in laparoscopic surgery like laparoscopic cholecystectomy find that patients with ischaemic heart disease stand laparoscopic cholecystectomy better than open cholecystectomy, both intraoperatively and postoperatively. Consent for open surgery should always be taken prior to LS. Preoperative laxative and liquid or light diet is also advised for 2 days prior to LS. Administration of Peglac 12 hours preoperatively helps in keeping bowels empty. Ranitidine or other H2 receptor antagonists to increase pH of gastric contents and metoclopramide to increase gastric emptying and to increase tone of oesophageal sphincter may be given just prior to anaesthesia. Compression stockings to help reduce pooling of blood in limbs due to peripheral vascular dilatation effect of CO2 insufflation and anaesthesia.

Anaesthesia Technique
As with open surgery, minimal access surgery can also be performed under local, regional, total intravenous or general anaesthesia.

Local Anaesthesia
Use of local anaesthesia is possible for shorter procedures e.g. diagnostic laparoscopy, tubectomy and in camps. However patient should be monitored carefully to avoid cardio respiratory depression and allow rapid recovery.

Regional anaesthesia
Regional anaesthesia like spinal or epidural anaesthesia is practised routinely by some anaesthesiologists even for major surgeries like laparoscopic Wertheim’s hysterectomy. However this is not the common anaesthetic practice as more sedation is needed and deep Trendelenberg position there is greater pressure on the diaphragm affecting changes in respiratory function.

Total intravenous anaesthesia (TIVA)
With availability of injectable Propofol which is ultra short acting, and Fentanyl which is a potent analgesic and sedative, and Fulsed which is also potent sedative, TIVA is much safer and effective anaesthesia for LS. Muscle relaxant can be used with these agents and patient can be ventilated with air oxygen mixture after intubation. This technique allows rapid and full recovery postoperatively and early discharge from the hospital.

General Anaesthesia
This is the most common technique used by majority of anaesthesiologists. To avoid dryness and unnecessary tachycardia, atropine or glycopyrrolate can be given with the inducing agent which is usually propofol or thiopentone. Short acting muscle relaxant like atracurium or vecuronium is commonly used; scoline is avoided as it can give postoperative myalgia after 24 hours. Nitrous oxide is avoided in long cases as it may give rise to distension of intestines creating problems for the surgeon.

Inhalation agents like isoflurane and seviflurane are very expensive for common use but should not be spared when it is needed for patients with ischaemic heart disease. Halothane has been used by most anaesthetists. Intubation and positive pressure ventilation should be carried out for all cases of upper abdominal LS e.g. cholecystectomy or repair of hiatus hernia. This prevents pneumothorax or pneumomediastinum due to gas escaping from the abdomen to the thorax.

Physiological changes during laparoscopy
The physiological changes during laparoscopy are summarized in Table 1.

Monitoring during LS
End tidal CO2 (ETCO2) monitoring
As carbon dioxide is insufflated into the abdomen for LS, monitoring of ETCO2 is essential during LS. To avoid hypercarbia, rate and depth of ventilation should be adjusted as per the need of each patient. If LS lasts more than 2 hours ETCO2 may not be a good indicator of pCO2. Hence patient should be ventilated for 20-30 minutes after stopping CO2 insufflation. These patients also need longer observation in recovery room. Gas embolism in major vessel is diagnosed when there is sudden fall in ETCO2. When there is continuous slower absorption of CO2 from the peritoneal cavity there is rise in ETCO2 and hypercarbia.

Pulse Oxymetry
Monitoring of SpO2 is also necessary during LS. Fall in peripheral oxygenation could be due to respiratory or circulatory cause e.g. pneumothorax, gas embolism, hypotension etc.
ECG, BP, and Body Temperature should also be monitored continuously.

Choice of gas for insufflation
In the present day laparoscopy, carbon dioxide is the only gas that is preferred for insufflation. Gasless laparoscopy is also practised by many surgeons using various techniques for lifting the abdominal wall e.g. Dr. Nande’s laparolift. As carbon dioxide insufflation is avoided, this technique is safer for patients with cardiac or respiratory problems.

Complications of LS
Complications of LS are rare. They are generally caused by over distension, pneumoperitoneum and positioning due to hypercarbia and sympathetic stimulation. These may be sudden vagal stimulation or compression of inferior vena cava due to high intra-abdominal pressure (> 14 mm of Hg). Hence ECG and BP monitoring is essential. Respiratory complications like hypercapnia, undiagnosed pneumothorax, splinting of diaphragm due to deep Trendelenberg position and increased airway pressure can occur. Pneumothorax and pneumomediastinum may occur when gas escapes from under the diaphragm. Hypothermia can occur due to cold CO2, cold irrigation fluid and cool temperatures in operation theatre. It should be prevented by using warming blanket during surgery and by using warm fluid for irrigation and infusion during LS.

A close communication between the surgeon and anaesthesiologist throughout the procedure will help both in reducing the operative time as well as the complications that may arise during the procedure.

 

 
Honorary Consultant Anaesthetist, Bombay Hospital, Mumbai.
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