One lung anesthesia

Thoracic anesthesia with one lung ventilation is challenging. The anesthetist is faced with demands of establishing proper isolation of one lung from the other in order to facilitate good surgical exposure and prevent intraoperative complications. Due to advances in one lung ventilation [OLV] strategies and equipment, complex intrathoracic procedures are being performed with success. During onelung ventilation, mismatch of perfusion leads to an increase in shunt and dead space. Hypoxemia is an inevitable adverse consequence of OLV. Prompt management is required. This may particularly occur with high airway pressure caused by malpositioned double lumen tube or endobronchial blocker causing incomplete lung ventilation and/or airway obstruction. Other causes may be bronchospasm, air trapping with dynamic hyperinflation pneumothorax of the ventilated lung and coughing due to inadequate muscle relaxation. One lung induced acute lung injury [ALI] must be recognized. Acute lung injury [ALI] is a major cause of overall mortality after thoracic surgery. Protective ventilation strategies have been identified and recommended by researchers for implementation during OLV. This includes small tidal volumes based on ideal body weight, reducing the fraction of inspired oxygen [FiO2], use of positive end-expiratory pressure [PEEP] to the ventilated lung, and low peak and plateau airway pressures. One-lung ventilation has to be managed from the start before beginning OLV till the end of OLV [in order to prevent complications like ALI]. Extreme care is required during re-expansion of the lung towards the end of OLV. Noninvasive ventilation may be used during this period to improve oxygenation

Trans-sternal thymectomy in myasthenia gravis patients with laryngeal mask airway

TUIP is as effective as TURP in achieving maximum flow rate but TUIP was superior in terms of shorter operative time, less retrograde ejaculation and less need of blood transfusion. A descriptive case series. Department of Anaesthesia, Jinnah Postgraduate Medical Centre Karachi, from June 2006 to December 2010. All patients who underwent trans-sternal thymectomy for myasthenia gravis under laryngeal mask airway [Prosea] were included. They were maintained with inhalation agent and analgesics. Muscle relaxants were avoided in all the patients. The haemodynamics and blood gases were monitored perioperatively. A total of sixteen patients underwent the procedure using laryngeal mask airway [Proseal]. There were ten females and 6 males. Mean age at presentation was 26.5 +/- 10.4 year. The haemodynamics and blood gases were well maintained perioperatively. Fourteen patients [87.5%] could be extubated successfully. Two patients needed intubation and ventilation; one for 9 hours and other for 24 hours. These patients were identified as those who were on higher doses of pyridostigmine [>240 mg] and had severe pre-operative muscle weakness. The use of laryngeal mask airway [Prosea] for patients undergoing trans-sternal thymectomy is a satisfactory alternative to tracheal intubation for those patients of myasthenia gravis who do not require airway protection. Avoidance of muscle relaxants and use of laryngeal mask airway [prosea] in facilitate rapid emergence and allowed early extubation

Role of dexamethasone for prevention of post-extubation airway obstruction in critically ill adult patients

To evaluate whether dexamethasone started 24 hours prior to planned tracheal extubation in adults, can prevent post-extubation laryngeal oedema. Randomized placebo-controlled double-blind trial. Department of Anaesthsiology, Surgical ICU and Pain Management, Jinnah Postgraduate Medical Centre Karachi, from August 2006 to July 2008. Ninety-two patients who met weaning criteria after being intubated for more than 48 hours, with a cuff leak volume [CLV] of less than 110 ml were randomly allocated to two groups; receive either intravenous dexamethasone [5 mg] or identical volume of intravenous placebo [normal saline], and continued every six hours thereafter, for a total of four doses [total dose 20 mg] on the day preceding extubation. Cuff leak volume was measured at the time of the first injection, and one hour after each injection and 24 hours after the last injection. Patients were extubated twenty-four hours after the last injection of dexamethasone or identical volume of intravenous placebo. Occurrence of stridor was noted within 48 hours of extubation. Dexamethasone injection 24 hours prior to extubation increased the CLV significantly [P=0.001]. Post-extubation stridor was 54.6% significantly lower in the dexamethasone group than in placebo group [6/46 versus 15/46, P=0.025]. Dexamethasone given every six hours intravenously, commencing 24 hours before a planned tracheal extubation, substantially reduced the incidence of post-extubation stridor and re-intubation, in adult patients at high risk for post-extubation laryngeal oedema, as identified by the cuff leak test