End-tidal CO2 for prediction of cardiac output following weaning from cardiopulmonary bypass

This prospective study included 32 patients undergoing cardiopulmonary bypass (CPB) for elective coronary artery bypass grafting correlates the respiratory end-tidal CO2 (ETCO2) during partial separation from CPB with cardiac output (CO) following weaning from CPB. After induction of general anesthesia, a pulmonary artery catheter was inserted for measurement of cardiac output by thermodilution. Patients were monitored using a 5-lead ECG, pulse oximeter, invasive blood pressure monitoring, rectal temperature probe, and end-tidal capnography. At the end of surgery, patients were weaned from CPB in a stepwise fashion. Respiratory ETCO2 and in-line venous oximetry were continuously monitored during weaning. The ETCO2 was recorded at quarter pump flow and after complete weaning from CPB. Following weaning from CPB, CO was measured by thermodilution. The CO values were correlated with the ETCO2 during partial bypass and following weaning from bypass. Regression analysis of ETCO2 at quarter-flow and post-bypass CO showed significant correlation (r = 0.57, p < .001). Also, regression analysis of ETCO2 after complete weaning from bypass and post-bypass CO showed significant correlation (r = 0.6, p = .002). The correlation between ETCO2 and CO showed that an ETCO2 >30 mm Hg during partial CPB will always predict an adequate CO following weaning from CPB. An ETCO2 <30 mm Hg may denote either a low or a normal cardiac output and hence other predictive parameters such as SvO2 must be added.     

Anesthetic management for a patient with myasthenia gravis undergoing coronary artery bypass graft

PURPOSE: Report the clinical management of a patient having Myasthenia Gravis (MG), undergoing cardiopulmonary bypass (CPB). CLINICAL FEATURES: A 71-yr-old man having MG (Osserman IIB), was admitted for coronary artery bypass graft (CABG) under CPB. Optimization of the patient was achieved preoperatively. Thymectomy was done following midsternotomy. Continuous monitoring of the neuromuscular transmission (NMT) was maintained throughout the perioperative period. The hemodilutional effect of CPB was counteracted by the hypothermia resulting in maintenance of cisatracurium requirements at the same levels as the prebypass period. Extubation of the trachea was done after ensuring adequate recovery of the NMT and respiratory function. Oral myasthenic therapy was resumed following extubation. CONCLUSION: A myasthenic patient can safely undergo CPB provided adequate preoperative optimization is achieved. Continuous monitoring of the NMT must be throughout the perioperative period. Thymectomy is recommended in the myasthenic patient since it may improve the outcome. Extubation of the trachea is to be done after ensuring adequate NMT and respiratory function.     

Advancing the tracheal tube over a flexible fiberoptic bronchoscope by a sleeve mounted on the insertion cord

The advancement of an endotracheal tube (ETT) over a flexible fiberoptic bronchoscope (FOB) is often impeded at the glottis. This is attributed to the creation of a cleft by the difference in the outer diameter of the fiberscope and the internal diameter of the tube. We designed a conical-shaped polyvinyl chloride sleeve to fit the insertion cord. This report compares the ease of advancement of the tube over a sleeved versus a nonsleeved bronchoscope. General anesthesia was induced, and one anesthesiologist introduced the FOB (a 3.8-mm Olympus LF2). Patients were randomly assigned to undergo tracheal intubation with the regular bronchoscope (25 patients) or the sleeved bronchoscope (25 patients). The FOB was advanced to approximately 1 cm above the carina. A blinded operator advanced the tube over the bronchoscope. The ETT was successfully advanced over the nonsleeved bronchoscope into the trachea on the first attempt in 64% of the patients, whereas tracheal intubation succeeded from the first attempt in 96% of patients when the sleeved FOB was used (P < 0.05). Advancement of the ETT over the fiberscope can be facilitated by using a conically shaped sleeve mounted on the insertion cord. IMPLICATIONS: This report shows that a conical sleeve mounted on the insertion cord of a fiberoptic bronchoscope will facilitate advancing the endotracheal tube into the trachea.     

Oxygenation using tidal volume breathing after maximal exhalation

We compared, in volunteers, the oxygenation achieved by tidal volume breathing (TVB) over a 3-min period after maximal exhalation with that achieved by TVB alone. Twenty-three healthy volunteers underwent the two breathing techniques in a randomized order. A circle absorber system with an oxygen flow of 10 L/min was used. The end-expiratory oxygen concentration (EEO(2)) was monitored at 15-s intervals up to 3 min. TVB after maximal exhalation produced EEO(2) values of 68% +/- 5%, 75% +/- 5%, and 79% +/- 4% at 30, 45, and 60 s, respectively, which were significantly larger (P < 0.05) than the corresponding values obtained with TVB alone (58% +/- 5%, 66% +/- 6%, and 71% +/- 5%, respectively). In both techniques, the EEO(2) increased exponentially, with time constants of 35 s during TVB after maximal exhalation versus 58 s during TVB without prior maximal exhalation. In conclusion, maximal exhalation before TVB can hasten preoxygenation by decreasing the nitrogen content of the functional residual capacity, with a consequent increase of EEO(2) to approximately 70% in 30 s and 80% in 60 s. IMPLICATIONS: Oxygenation by using maximal exhalation before tidal volume breathing produced a significantly faster increase in end-expiratory oxygen concentration than oxygenation with tidal volume breathing alone.     

Intravenous lidocaine as adjuvant to sevoflurane anesthesia for endotracheal intubation in children

IMPLICATIONS: Supplementing a sevoflurane induction of anesthesia in children with IV lidocaine 2 mg/kg can suppress cough after tracheal intubation and thus improve intubating conditions. In addition, lidocaine minimizes blood pressure fluctuations after tracheal intubation.     

Epidural meperidine for control of autonomic hyperreflexia in a quadriplegic undergoing cystoscopy

Epidural meperidine was used to control autonomic hyperreflexia (AH) during cystoscopy and transuretheral sphincterotomy, in a quadriplegic patient who had chronic spinal cord transection at C6 level. Meperidine 100 mg diluted in 10 ml saline was injected in the epidural space at L3-L4 level. Within 10 minutes and throughout the surgical procedure, the blood pressure stabilized at 125/70-140/80 mmHg. Epidural meperidine produces selective blockade of the spinal opiate receptors and hence may block the nociceptive reflexes below the level of cord transection and prevent AH.     

Tuberculosis control in Sudan against seemingly insurmountable odds.

SETTING: Sudan, Africa's largest and one of its poorest countries, in which civil disturbance, resource limitation and communications difficulties are substantial impediments to delivery of health services. OBJECTIVES: To 1) illustrate the burden of tuberculosis; 2) review measures taken to control the disease; 3) outline the introduction of the DOTS strategy; and 4) demonstrate the trend in the output of the DOTS strategy. METHODS: Published information on general health, tuberculosis and health structure provide the setting. Routine reports illustrate the trend in case notification in Sudan, and outcome of treatment by period of enrollment on treatment (cohort). RESULTS: Since 1992, sputum smear microscopy centres have been established in existing health facilities (179 of a total 290 targeted centres). By the end of the second quarter of 1998, 82,860 cases of tuberculosis had been reported, of whom 52% were sputum smear-positive cases. Of these, 89% had no history of previous treatment for as much as one month. The treatment outcomes for 11,000 new smear-positive cases were reported by the end of the second quarter of 1997; the proportion of notified cases for whom treatment results were available increased from 16% in 1994 to 63% in 1996. Of these, 72% were successfully treated, increasing from 62% in 1994 to 73% in 1996. CONCLUSIONS: Despite seemingly overwhelming odds, the DOTS strategy has been successfully commenced and is in the process of expansion throughout the country, with monitoring of the quality of diagnostic examinations and improvements in treatment outcome. Further improvement is necessary, but appears feasible.