Thoracoscopic microsurgical technique for vertebral surgery--anesthetic considerations

Anesthesia management for robotically assisted endoscopic coronary artery bypass grafting on beating heart

OBJECTIVE

To outline the initial anesthetic experience for robotically assisted coronary artery bypass grafting surgery on beating heart using the da Vinci surgical system.

METHODS

Between February 2007 and September 2009, 76 patients received the surgery with the da Vinci S Surgical System. The crucial issue of anesthesia for the surgery is to deal with the hemodynamic compromise, hypoxia and hypercarbia relevant to one-lung ventilation (OLV), and intrathoracic insufflation of CO2 with positive pressure (CO2 pneumothorax).

RESULTS

After initiation of OLV and CO2 pneumothorax, PaO2 and mixed venous saturation showed a significant decrease. Meanwhile, the SpO2 decreased to 92% in 14 of the 76 patients. In these patients, application of continuous positive airway pressure setting 5 to 15 cm H2O to the collapsed lung resulted in an increase in PaO2 from 59 ± 12 to 115 ± 23 mm Hg (P < 0.05). Moreover, at the beginning of CO2 pneumothorax, the most dramatic fall in mean arterial pressure and cardiac index was showed with an increase in mean pulmonary artery pressure and heart rate. The hemodynamic compromise was counteracted by transfusion and inotropes/vasopressors. Postoperatively, the average extubation time was 7.5 ± 3.1 hours, and median intensive care unit length of stay was 21 hours. One patient remained in the intensive care unit for 3 days for treatment of a postoperative pneumonia. There were two cases of new onset postoperative atrial fibrillation. All patients were discharged home 4 to 7 days after surgery.

CONCLUSIONS

Anesthetic management for the procedures requires detailed knowledge of OLV and CO2 pneumothorax in addition to expertise required in conventional cardiac surgery.

[Anesthesia for video-assisted surgery of the thoracic and lumbar spine: a survey of 44 patients]

INTRODUCTION

The development of video-assisted surgery of the dorsolumbar spine has led to the need for adaptations for appropriate anesthetic management. Data concerning anesthesia for such surgery is very sparse in the literature.

AIM OF THE STUDY

The aim of this retrospective study of 44 patients was to learn more about anesthesia practices used for patients undergoing this type of surgery.

PATIENTS AND METHOD

The files of 44 patients were studied retrospectively. Epidemiologic data and the perioperative phase were analysed.

RESULTS

The preoperative phase was not specific with preoperative assessment adapted to each patient. Similarly, monitoring practices during the surgical procedure were not specific. The choice of the anesthetic agents depended on the patient's clinical status. For tracheal intubation, care was taken to enable lung exclusion, even if not often used. Thoracic drainage at the end of the surgery was required in the event of imperfect hemostasis and in selected patients was replaced by pneumothorax exsufflation during closure. The postoperative period was uneventful and did not require admission to intensive care; non-specific analgesia was used.

DISCUSSION

Adaptations of anesthetic practices are required each time a new surgical technique is developed. Excepting lung exclusion, anesthesia for video-assisted dorsolumbar spine surgery is not specific.

Segmental myocardial wall motion during minimally invasive coronary artery bypass grafting using open and endoscopic surgical techniques

Current options for minimally invasive surgical treatment of single-vessel coronary artery disease include beating heart procedures without cardiopulmonary bypass (CPB) via mini-thoracotomy (MIDCAB) and totally endoscopic robot-assisted techniques (TECAB) with CPB. Both procedures are associated with potential myocardial stress before revascularization, such as single-lung ventilation (SLV), temporary coronary artery occlusion, cardiac luxation, intrathoracic carbon dioxide insufflation, and extended CPB and operating time. In this echocardiographic study we sought to evaluate the extent of intraoperative segmental wall motion abnormalities (SWMA) during MIDCAB and TECAB surgery and to identify factors affecting SWMA. Forty-six patients with single-vessel coronary artery disease were studied. Sixteen patients were operated using the MIDCAB technique and 30 patients with TECAB. In both groups sequential transesophageal echocardiograms were recorded during the entire procedure. Hemodynamic data and oxygenation variables were acquired simultaneously. In both groups, mild but obvious perioperative SWMA were identified and noted to increase during the course of the operation. These SWMA were more pronounced in the TECAB group. Independent of operating time, these changes disappeared completely after revascularization. No significant hemodynamic compromise was observed. We conclude that MIDCAB and TECAB techniques are associated with significant perioperative SWMA. The appearance of more profound SWMA in the TECAB group compared with the MIDCAB patients might have been the result of intrathoracic CO(2) insufflation, as SLV was used in both groups. No persistent SWMA or post-CPB SWMA were apparent in either group. More extensive intraoperative ventricular SWMA was detected in the TECAB group, suggesting that a more frequent risk for right ventricular dysfunction may exist during TECAB procedures.

Segmental wall motion abnormalities during telerobotic totally endoscopic coronary artery bypass grafting

In addition to single-lung ventilation (SLV), intrathoracic CO2 insufflation is mandatory for adequate exposure during totally endoscopic coronary artery bypass grafting. With transesophageal echocardiography, we investigated biventricular myocardial wall motion in 25 patients with isolated disease of the left anterior descending coronary artery who underwent totally endoscopic coronary artery bypass grafting with the "Da Vinci" robotic surgical system. At distinct time points during the operation, a cine loop of both ventricles was registered from a transgastric mid-short-axis view. Myocardial wall motion analysis was performed according to an established segmentation model of the left ventricle and to an established five-point scale for wall motion (1, normal; 5, dyskinesia). Significant alterations from preoperative baseline wall motion were visible in the septal, inferior, and anterior segments of the left ventricle at some time during the prebypass period, combined with a markedly decreased PaO2 under SLV and increased intrathoracic pressure. The same findings applied to the right ventricle; however, wall motion abnormalities were more pronounced here. After myocardial revascularization, weaning from cardiopulmonary bypass, CO2 deflation, and return to double-lung ventilation, myocardial wall motion recovered to baseline values. Clinically significant hemodynamic instability did not occur. The data suggest that robot-assisted coronary artery bypass grafting leads to significant prebypass alterations of biventricular segmental wall motion. On the basis of our data, it cannot be definitively stated whether the observed results were due to reduced oxygenation during SLV and thus "real" myocardial ischemia, intrathoracic CO2 insufflation with positive pressure leading to mechanical compromise of the heart, absolute or relative hypovolemia, or a combination of these factors. However, in this cohort, which consisted of patients with single-vessel disease and good ventricular function, these changes were of limited clinical relevance.

IMPLICATIONS

Segmental myocardial wall motion was evaluated with transesophageal echocardiography during robot-assisted totally endoscopic coronary artery bypass grafting. Significant biventricular segmental wall motion abnormalities occurred before cardiopulmonary bypass under single-lung ventilation and carbon dioxide insufflation. The changes in myocardial wall motion were of limited clinical relevance.

Hemodynamics and gas exchange during carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting

BACKGROUND

In addition to single-lung ventilation (SLV), positive-pressure CO2 insufflation is mandatory for totally endoscopic coronary artery bypass grafting. Studies on the effects of unilateral CO2 insufflation on hemodynamics produced controversial results, and bilateral insufflation has not been studied to our knowledge. The present study sought to investigate hemodynamics and gas exchange during unilateral and bilateral CO2 insufflation in patients who underwent totally endoscopic coronary artery bypass grafting.

METHODS

Eleven hemodynamic and gas exchange variables were monitored during 22 totally endoscopic coronary artery bypass grafting procedures with unilateral (n = 17) or bilateral (n = 5) CO2 insufflation at a pressure of 10 to 12 mm Hg. Data were obtained at baseline with double-lung ventilation, after institution of SLV, during insufflation, after cardiopulmonary bypass during SLV, and after return to double-lung ventilation.

RESULTS

Arterial oxygen tension decreased significantly during SLV, whereas the peak inspiratory pressure increased. In addition, central venous pressure and heart rate increased significantly during insufflation, but mean arterial pressure remained unchanged. Although the end-tidal CO2 pressure did not change, arterial carbon dioxide tension increased progressively to a maximum of 44.6 +/- 5.9 mm Hg during unilateral insufflation, and 55.7 +/- 14.6 mm Hg during bilateral insufflation (p < 0.05 versus baseline and between groups). Mixed venous oxygen saturation declined during SLV regardless of CO2 insufflation and recovered to baseline once double-lung ventilation was restarted. Left and right ventricular ejection fractions remained unaltered. No patient required inotropic or vasopressor support.

CONCLUSIONS

Carbon dioxide insufflation for totally endoscopic coronary artery bypass grafting with SLV had no adverse effects on hemodynamics. In contrast to a moderate increase of arterial carbon dioxide tension during unilateral insufflation, markedly elevated arterial carbon dioxide tension levels remain a cause of concern during bilateral insufflation.

Anesthetic considerations for thoracic neurosurgical procedures

Anesthetic considerations for thoracic and thoracoscopic neurosurgical procedures are considered, emphasizing the need to provide anesthetic stability during prolonged periods of one-lung ventilation, while optimizing conditions for intraoperative monitoring of spinal cord integrity.