Comparison of efficacy of labetalol and fentanyl for attenuating reflex responses to laryngoscopy and intubation

Stress response due to laryngoscopy and intubation has been universally recognized phenomenon resulting in increase in heart rate, arterial, intracranial, and intraocular pressure. Various pharmacological approaches have been used to blunt or attenuate such pressure responses. This prospective, randomized, placebo controlled, double blinded study was designed to compare the efficacy of bolus dose of Labetalol and Fentanyl for attenuating reflex responses to laryngoscopy and intubation. Ninety patients with physical status of ASA I and II were scheduled for elective surgery under standard protocol of general anaesthesia, randomly allocated into three groups, consisting of 30 patients in each group, assigned as C (Control), L (Labetalol), and F (Fentanyl). In control group 10ml of 0.9% saline, in Labetalol group 0.25 mg/kg Labetalol and in Fentanyl group 2μgm/kg of Fentanyl were given intravenously at 3 minutes prior to laryngoscopy and intubation. Pulse rate, systolic, diastolic, mean arterial pressure and rate pressure products (RPP) were recorded before and after premedication, after administration of study drugs and at 1, 3, 5, 10 and 15 minutes after intubation. For statistical analysis of data, ANOVA tests were performed for comparison between groups. There were an increase in heart rate, systolic, diastolic, mean arterial pressures and rate pressure product in all the three groups after intubation in comparison to base line value. But the rise was minimum in L and F group as compared to C group which is statistically significant and also minimum in L group as compared to F group. So Labetalol is better agent for attenuation of laryngoscopic and intubation reflex.

Haemodynamic and end tidal CO₂ changes during laparoscopic cholecystectomy under general anaesthesia

A prospective observational study was done on 50 patients to investigate the haemodynamic and end tidal CO₂ (EtCO₂) changes in healthy patients without cardiopulmonary pathology during elective laparoscopic cholecystectomy in head up position under standard protocol of general anaesthesia. During surgery, intra abdominal pressure was maintained at 15 mmHg by a CO₂ insufflator and minute ventilation was controlled with a constant tidal volume and fixed respiratory rate. Haemodynamic parameters, EtCO₂, SpO₂ and ECG were recorded before and after induction and positioning of the patients and at 5 minutes interval for the first 30 minutes, then 10 minutes interval for the rest of the period. Highly significant increase (p<0.001) in pulse rate, systolic, diastolic and mean arterial pressure occurred at 30 minutes after insufflations and positioning of the patient. A very highly significant (p<0.001) increase in EtCO₂ from the base line was at 40 minutes after insufflations and positioning of the patients. There was no change in SpO₂ and ECG. This study supports the significant physiological changes in terms of haemodynamic and EtCO₂ during laparoscopic cholecystectomy and recommends the meticulous monitoring of these parameters during the surgery and balance the benefit of laparoscopy against the intra operative risk.

Electrosurgical smoke: a real concern

Electrosurgical techniques including laser surgery have expanded greatly in recent years. Pyrolysis of tissue produces smoke. Recently the smoke is being analyzed using Gas Chromatography-Mass Spectrometry. The nature of smoke depends on the rise of temperature of tissue during electro-surgery. The smoke produced at high temperatures contains low concentration of Group-I carcinogens (IARC) such as Benzene, Hydrogen cyanide, Formaldehyde 1,3-Butadiene and Acrylonitrile. Bioaerosol produced at low temperature as in harmonic scissors may contain live multidrug resistant Mycobacterium tuberculosis, viral DNA of HBV, HCV, HIV and HPV. It also contains live malignant cells and dead cellular materials. These produce an unquantified infection risk. The obnoxious smoke causes ocular and upper respiratory tract irritation, creates visual problems for surgeons. Surgical masks are not capable of filtering the produced bioaerosol. Removal of smoke from the site of operation by local exhaust ventilation is not complete. When produced in a closed cavity as in laparoscopic surgery the patient also suffers from carboxyhaemoglobinaemia and methaemoglobinaemia. Methemoglobinaemia is not detected by standard pulse-oximetry. Laser smoke produces congestive interstitial pneumonia, bronchiolitis and emphysema in rats. Chromosomal aberration and sister chromatid exchange have been found in lymphocyte culture of operating room personnel. Occupational safety and health authorities like Occupational Safety and Health Administration (OSHA), National Institute for Occupational safety and Health (NIOSH), American National Standard Institute (ANSI) and Association of Operating room nurses (AORN) are trying to find effective ways for removal of smoke from site of operation and also the real risk to operating room personnel. Answer lies in minimizing the use of electrocautery whenever possible and completes removal of harmful smoke.

Haemodynamic and end tidal CO2 changes state after inflation and deflation of pneumatic tourniquet on extremities

The use of a tourniquet for obtaining a bloodless field is an essential and accepted tool for extremity surgery. A prospective study was done on 30 adult patients undergoing elective limb surgery requiring tourniquet application for haemodynamic and End tidal CO2 (EtCO2) changes. After the induction of general anaesthesia a tourniquet was applied on the limb. There was gradual increase in heart rate & EtCO2 through out the whole period of tourniquet inflation. There was also significant increase of mean arterial pressure during the inflation period. At the end of surgery tourniquet was deflated. Tourniquet time was 76.83+/-16.94 minutes. After deflation of the tourniquet, heart rate & EtCO2 value increased & the values were maximum at 5 minutes. These values came down to the base line at 15 minutes. There was significant decrease of mean arterial pressure (MAP) at 5 minute; it also came to the base at 15 minute. These changes are usually benign but can be significant in patients with co-existing cardiovascular & intracranial diseases. In conclusion, we recommend the haemodynamic and End tidal CO2 monitoring as well as rapid fluid infusion along with hyperventilation for 15-30 minutes after deflation of tourniquet.

Sub arachnoid block for emergency cesarean section in a pituitary dwarf

Anaesthesia for parturient patients with dwarfism is an uncommon problem faced by anaesthesiologists. There is an ongoing debate regarding general versus regional anaesthesia in these cases. In many centers there is lack of facilities for epidural or continuous epidural anaesthesia. A primiparous dwarf woman of 27 years old having 124 cm height and 37 kg weight was admitted in Mymensingh Medical College Hospital for elective cesarean section due to cephalopelvic disproportion. She was diagnosed as a case of pituitary dwarf previously on antenatal checkup depending on both clinical and endocrine ground. After admission she suddenly developed respiratory distress with less foetal movement and presented in our department for emergency cesarean section. We have managed the case by sub-arachnoid block (SAB) using 7.5 mg (1.5 ml) of 0.5% heavy bupivacaine at a level of L3-L4 interspace having adequate level of block and analgesia. The case was managed successfully and uneventfully. In this presentation, the role of SAB and a management guideline has been highlighted.