Truncus arteriosus is a congenital cardiovascular anomaly characterized by a single arterial vessel (truncus) with one valve arising from the heart. The truncus overrides a large perimembranous ventricular septal defect and receives mixed blood from both ventricles and supplies blood to the pulmonary, systemic, and coronary circulation, the ratio of the bloodflow vary according to the different vascular resistances. The anomaly is divided into four types according to Collett and Edwards classification on the basis of the origin of the pulmonary arteries from the truncal artery. In truncus, the goal is to balance the circulation to obtain QP:QS = 1 to maintain reasonable oxygen saturation as well as adequate organ perfusion. Careful titration of anesthetic agents and careful monitoring of their hemodynamic effects and appropriate measures to adjust pulmonary (PVR) and systemic vascular (SVR) resistances and cardiac performance are probably more important than the selection of a particular anesthetic agent. Postoperatively, low cardiac output can be expected because of high PVR and right ventricular failure. High PVR, both sustained and paroxysmal, should be anticipated. Pulmonary hypertensive crisis presents as low cardiac output and right ventricular failure. Avoidance of these potentially fatal events is essential to decrease the mortality and morbidity associated with repair. Events that trigger a hypertensive crisis, such as hypoxia, hypercapnia, acidosis, pain, airway stimulation, and left ventricular failure, must be avoided.
Several recent studies have suggested that repetitive transcranial magnetic stimulation (rTMS) can temporarily reduce the need for analgesia postoperatively. We aimed to determine the effects of prefrontal cortex stimulation using TMS on post-thoracotomy pain.
Twenty patients who had undergone thoracic surgery were studied. Immediately after surgery, the patients were randomly assigned to receive 20 min of active or sham rTMS (10 Hz, 10-s ON, and 20-s OFF for a total of 4000 pulses). Participants rated pain and mood twice per day using visual analog scale.
Groups were similar at baseline in terms of the BMI, age, mood ratings, pain ratings, surgery duration, time under anesthesia, and surgical anesthesia methods. Active prefrontal rTMS was associated with a 40% reduction in total morphine use compared with sham during the 48 h after surgery. Participants who received active rTMS also reported significantly lower ratings of postoperative pain-on-average and pain-at-its-worst than participants receiving sham.
A single session of postoperative prefrontal rTMS was associated with a reduction in post-thoracotomy pain. This is clinically important because it offers the potential of reducing the need for the postoperative use of analgesia such as morphine. These analgesics are associated with complications (e.g. respiratory depression), especially in patients undergoing thoracotomy for chest diseases.
Bispectral index (BIS) monitoring has been established as a standard monitoring method for the assessment of the depth of anesthesia during living donor liver transplantation (LDLT). We tested the sensitivity and specificity of BIS readings during LDLT in predicting the postoperative 3-month survival.
After receiving ethical approval, 42 patients who had undergone LDLT under sevoflurane–fentanyl–rocuronium anesthesia were studied. Correlations between BIS readings and extubation time, postoperative liver function tests, intensive care unit stay, and 3-month mortality were tested. Receiver operating characteristic curves were generated to determine the sensitivity and specificity of the BIS readings during different phases of surgery in predicting the survival outcome.
The extubation time, liver function tests, coagulation factors V and VII, and intensive care unit stay were not statistically correlated with the BIS values. Receiver operating characteristic curve analyses showed reasonable sensitivity and specificity of mean BIS values during hepatic resection and neohepatic periods for predicting the 3-month mortality, with an unweighted accuracy of 76 and 73%, respectively. The nonsurvivors had significantly higher mean BIS values during the neohepatic phase (P<0.05).
The researchers concluded that the BIS monitoring during hepatic resection and neohepatic phases seems to be a suitable noninvasive monitoring tool with reasonable sensitivity and specificity for predicting the 3-month mortality after LDLT under sevoflurane–fentanyl anesthesia.
Nitric oxide (NO) may improve left ventrcular dysfunction after cardiac surgery. We have reported a case of severe left ventricular dysfunction and refractory hypoxemia after a two-vessel coronary artery grafting surgery. Different protective ventilation strategies and circulatory support with infusions of epinephrine and dopamine and intra-aortic balloon pumping failed to induce improvements in the cardiopulmonary function. In light of the worsening myocardial function and refractory hypoxemia, inhaled NO 20 ppm was initiated. This was followed by a progressive rapid improvement in the left ventricular function and oxygenation index, and gradual resolution of radiological lung infiltrates. The use of NO inhalation can be a safe and effective treatment modality for the refractory left ventricular dysfunction and worsening hypoxemia after coronary artery bypass grafting (CABG) surgery.