Haemodynamic changes during thoracoscopic surgery the effects of one-lung ventilation compared with carbon dioxide insufflation

Treating Spontaneous Pneumothorax Using an Innovative Surgical Technique Called Capnodissection Pleurectomy: Case Report

Spontaneous pneumothorax is one of the most common conditions encountered in thoracic surgery. This condition can be treated conservatively or surgically based on indications and guidelines. Traditional surgical management includes pleurodesis (mechanical or chemical) in addition to bullectomy if the bullae can be identified. Mechanical pleurodesis is usually performed by surgical pleurectomy or pleural abrasion. In this case report, we present a case of a young patient with spontaneous pneumothorax who needed a surgical intervention. We performed a new, innovative surgical technique for surgical pleurectomy where we used carbon dioxide for dissection of the parietal pleura (capnodissection). This technique may provide similar efficiency to the traditional procedure but with less risk of bleeding and complications.

Perioperative cardiovascular pathophysiology in patients undergoing lung resection surgery: a narrative review

Although thoracic surgery is understood to confer a high risk of postoperative respiratory complications, the substantial haemodynamic challenges posed are less well appreciated. This review highlights the influence of cardiovascular comorbidity on outcome, reviews the complex pathophysiological changes inherent in one-lung ventilation and lung resection, and examines their influence on cardiovascular complications and postoperative functional limitation. There is now good evidence for the presence of right ventricular dysfunction postoperatively, a finding that persists to at least 3 months. This dysfunction results from increased right ventricular afterload occurring both intraoperatively and persisting postoperatively. Although many patients adapt well, those with reduced right ventricular contractile reserve and reduced pulmonary vascular flow reserve might struggle. Postoperative right ventricular dysfunction has been implicated in the aetiology of postoperative atrial fibrillation and perioperative myocardial injury, both common cardiovascular complications which are increasingly being appreciated to have impact long into the postoperative period. In response to the physiological demands of critical illness or exercise, contractile reserve, flow reserve, or both can be overwhelmed resulting in acute decompensation or impaired long-term functional capacity. Aiding adaptation to the unique perioperative physiology seen in patients undergoing thoracic surgery could provide a novel therapeutic avenue to prevent cardiovascular complications and improve long-term functional capacity after surgery.

Effects of Iloprost on Arterial Oxygenation and Lung Mechanics during One-Lung Ventilation in Supine-Positioned Patients: A Randomized Controlled Study

Patients undergoing one-lung ventilation (OLV) in the supine position face an increased risk of intraoperative hypoxia compared with those in the lateral decubitus position. We hypothesized that iloprost (ILO) inhalation improves arterial oxygenation and lung mechanics. Sixty-four patients were enrolled and allocated to either the ILO or control group (n = 32 each), to whom ILO or normal saline was administered. The partial pressure of the arterial oxygen/fraction of inspired oxygen (PaO₂/FiO₂) ratio, dynamic compliance, alveolar dead space, and hemodynamic variables were assessed 20 min after anesthesia induction with both lungs ventilated (T1) and 20 min after drug nebulization in OLV (T2). A linear mixed model adjusted for group and time was used to analyze repeated variables. While the alveolar dead space remained unchanged in the ILO group, it increased at T2 in the control group (n = 30 each) (p = 0.002). No significant differences were observed in the heart rate, mean blood pressure, PaO₂/FiO₂ ratio, or dynamic compliance in either group. Selective ILO nebulization was inadequate to enhance oxygenation parameters during OLV in the supine position. However, it favorably affected alveolar ventilation during OLV in supine-positioned patients without adverse hemodynamic effects.

Comparison of two-lung and one-lung ventilation in bilateral video-assisted thoracoscopic extended thymectomy in myasthenia gravis: a retrospective study

Background

Myasthenia gravis (MG) is an autoimmune disease, and early thymectomy is recommended. Since the introduction of video-assisted thoracoscopic surgery, the safety and effectiveness of carbon dioxide insufflation in the thoracic cavity (capnothorax) has been controversial. This study aimed to compare the safety and effectiveness of ventilation methods in bilateral video-assisted thoracoscopic extended thymectomy (BVET) with capnothorax.

Methods

We retrospectively investigated the medical records of patients with MG who underwent BVET between August 2016 and January 2018. Patients were divided into two groups: group D (n = 26) for one-lung ventilation and group S (n = 28) for two-lung ventilation. We set nine anesthesia time points (T0–T8) and collected respiratory and hemodynamic variables, including arterial O₂ index (PaO₂/FiO₂).

Results

SpO₂ at T1–T3 and T8 was significantly lower in group D than in group S. The FiO₂ in group S was lower than that in group D at all time points. The number of PaO₂/FiO₂ ≤ 300 and PaO₂/FiO₂ ≤ 200 events was significantly higher in group D than in group S. Hemodynamic variables were not significantly different between the two groups at any time point. The duration of surgery and anesthesia was shorter in group S than in group D.

Conclusions

This retrospective study suggests that anesthesia using two-lung ventilation during BVET with capnothorax is a safe and effective method to improve lung oxygenation and reduce anesthesia time.

Application of Continuous Positive Airway Pressure During Video-Assisted Thoracoscopic Surgery

Purpose of Review

Video-assisted thoracoscopic surgery (VATS) and robotic-assisted thoracoscopic surgery (RATS) are used for anatomic resection of early stage cancer. These surgical techniques require the use of one-lung ventilation (OLV). During OLV, an obligatory intrapulmonary shunt may produce hypoxemia. One method to correct hypoxemia is with the use of continuous positive airway pressure (CPAP). This review focuses on 1) the lung physiology of OLV; 2) application of CPAP in VATS or RATS during supine and lateral position; and 3) the application of CPAP in COVID-19 patients during OLV.

Recent Findings

Studies have shown the beneficial effects of CPAP to improve oxygenation during OLV while the patient is in the lateral decubitus position. In contrast, studies have shown no benefit on improving oxygenation with CPAP in patients undergoing OLV in supine position.

Summary

The application of CPAP to the non-dependent lung is one of the options to treat hypoxemia during VATS or RATS.

CO2 artificial pneumothorax on coagulation and fibrinolysis during thoracoscopic esophagectomy

BACKGROUND

CO2 artificial pneumothorax creates a sufficient operative field for thoracoscopic esophagectomy. However, it has potential complications and continuous CO2 insufflation may impede coagulation and fibrinolysis. We sought to compare the effects of CO2 artificial pneumothorax on perioperative coagulation and fibrinolysis during thoracoscopic esophagectomy.

METHODS

We investigated patients who underwent thoracoscopic esophagectomy with (group P, n = 24) or without CO2 artificial pneumothorax (group N, n = 24). The following parameters of coagulation-fibrinolysis function: intraoperative bleeding volume; serum levels of tissue plasminogen activator (t-PA), plasminogen activator inhibitor (PAI-1), thromboelastogram (TEG), D-Dimer; and arterial blood gas levels were compared with two groups.

RESULTS

Group P showed higher levels of PaCO2, reaction time (R) value and kinetics (K) value, but significantly lower pH value, alpha (α) angle and Maximum Amplitude (MA) value at 60 minutes after the initiation of CO2 artificial pneumothorax than group N ((P < .05, all). The t-PA level after CO2 insufflation for 60 minutes was significantly higher in group P than in group N (P < .05), but preoperative levels were gradually restored on cessation of CO2 insufflation for 30 min (P > .05). There was no significant difference in D-dimer.

CONCLUSION

CO2 artificial pneumothorax during thoracoscopic esophagectomy had a substantial impact on coagulation and fibrinolysis, inducing significant derangements in pH and PaCO2.

TRIAL REGISTRATION

The study was registered at the Chinese clinical trial registry (ChiCTR1800019004).

Preemptive one lung ventilation enhances lung collapse during thoracoscopic surgery: A randomized controlled trial

In routine practice, one lung ventilation (OLV) is initiated upon pleural opening. We conducted a randomized controlled trial to compare lung collapse after preemptive OLV versus conventional OLV in thoracoscopic surgery. A total of 67 patients were enrolled (34 with conventional OLV; 33 with preemptive OLV). Preemptive OLV was conducted by closing the DLT lumen to the non‐ventilated lung immediately upon assuming the lateral position with the distal port closed to the atmosphere until pleural opening (>6 minutes in all cases). Lung collapse was assessed at 1, 5, 10, 20, 30 and 40 minutes after pleural opening using a 10‐point rating scale (10: complete collapse). The primary end point was the duration from pleural opening to satisfactory lung collapse (score of 8). Secondary end points included PaO₂ and hypoxemia. The duration from pleural opening to satisfactory lung collapse was shorter in the preemptive OLV group (9.1 ± 1.2 vs. 14.1 ± 4.7 minutes, P < 0.01). PaO₂ was comparable between the two groups prior to anesthetic induction (T0), and 20 (T2), 40 minutes (T3) after pleural incision, but was lower in the preemptive OLV group at zero minutes after pleural incision (T1) (457.5 ± 19.0 vs. 483.1 ± 18.1 mmHg, P < 0.01). No patients in either group developed hypoxemia. In summary, preemptive OLV expedites lung collapse during thoracoscopic surgery with minimal safety concern.

Is two lung ventilation with artificial pneumothorax a better choice than one lung ventilation in minimally invasive esophagectomy?

Two lung ventilation (TLV) with artificial pneumothorax has been introduced into MIE for several years. A few researches have reported its clinical application, and proved its safety and feasibility. However, it is still controversial whether TLV with artificial pneumothorax is a better choice than one lung ventilation (OLV). Obviously, single lumen endotracheal tube is easy for intubation and intraoperative maintenance. Potential problems during intervention include hemodynamic changes, oxygenation, and air embolism. In this paper, present literature is reviewed about two and one lung ventilation in thoracoscopy, looking for clear conclusions for future application.

Optimal PEEP during one-lung ventilation with capnothorax: An experimental study

BACKGROUND

One-lung ventilation (OLV) with induced capnothorax carries the risk of severely impaired ventilation and circulation. Optimal PEEP may mitigate the physiological perturbations during these conditions.

METHODS

Right-sided OLV with capnothorax (16 cm H₂ O) on the left side was initiated in eight anesthetized, muscle-relaxed piglets. A recruitment maneuver and a decremental PEEP titration from PEEP 20 cm H₂ O to zero end-expiratory pressure (ZEEP) was performed. Regional ventilation and perfusion were studied with electrical impedance tomography and computer tomography of the chest was used. End-expiratory lung volume and hemodynamics were recorded and.

RESULTS

PaO₂ peaked at PEEP 12 cm H₂ O (49 ± 14 kPa) and decreased to 11 ± 5 kPa at ZEEP (P < 0.001). PaCO₂ was 9.5 ± 1.3 kPa at 20 cm H₂ O PEEP and did not change when PEEP step-wise was reduced to 12 cm H₂ O PaCO_2. At lower PEEP, PaCO₂ increased markedly. The ventilatory driving pressure was lowest at PEEP 14 cm H₂ O (19.6 ± 5.8 cm H₂ O) and increased to 38.3 ± 6.1 cm H₂ O at ZEEP (P < 0.001). When reducing PEEP below 12-14 cm H₂ O ventilation shifted from the dependent to the nondependent regions of the ventilated lung (P = 0.003), and perfusion shifted from the ventilated to the nonventilated lung (P = 0.02).

CONCLUSION

Optimal PEEP was 12-18 cm H₂ O and probably relates to capnothorax insufflation pressure. With suboptimal PEEP, ventilation/perfusion mismatch in the ventilated lung and redistribution of blood flow to the nonventilated lung occurred.

Cardiorespiratory effects of variable pressure thoracic insufflation in cats undergoing video-assisted thoracic surgery

OBJECTIVE

To evaluate the effects of intrathoracic insufflation on cardiorespiratory variables and working space in cats undergoing video-assisted thoracic surgery.

STUDY DESIGN

Prospective randomized study.

ANIMALS

Six healthy cats.

METHODS

Cats were anesthetized using a standardized protocol. A Swan-Ganz catheter was positioned in the pulmonary artery under fluoroscopic guidance for measurement of cardiac output. Intrathoracic pressures (ITP) of 0 (baseline), 3, and 5 mm Hg were induced with CO₂ and maintained for 30 minutes. Statistical comparison of cardiorespiratory variables was performed. After the procedures, all cats were recovered from anesthesia. Videos of thoracic working space at each ITP level were scored in a blinded fashion by 3 board-certified surgeons using a numerical scale from 0-10.

RESULTS

All cats tolerated insufflation with 3 and 5 mm Hg for 30 minutes without oxygen desaturation, although ventilatory levels had to be increased substantially to maintain eucapnia and oxygenation. Cardiac index was not significantly different from baseline after 30 minutes at 3 mm Hg but was significantly lower after 30 minutes at 5 mm Hg compared with 3 mm Hg. Oxygen delivery was unaffected by 3 or 5 mm Hg compared with baseline. Scores for working space increased between baseline and 3 and 5 mm Hg but were not different between 3 and 5 mm Hg.

CONCLUSION

CO₂ insufflation to 5 mm Hg seems well tolerated in healthy cats, provided ventilatory settings are substantially increased as ITP increases.

CLINICAL SIGNIFICANCE

Thoracic CO₂ insufflation of 3 mm Hg in cats during video-assisted thoracic surgery is associated with less hemodynamic perturbation than 5 mm Hg insufflation and may provide the benefit of improved working space compared with baseline.

CO2 during single incisional thoracoscopic bleb resection with two-lung ventilation

Background

CO₂ insufflation could provide a better surgical field during single-incision thoracoscopic surgery (SITS) with small tidal two-lung ventilation (ST-TLV). Here we compared the surgical field and physiological effects of ST-TLV with and without CO₂ during SITS.

Methods

Patients underwent scheduled SITS bullectomy. Surgery under ST-TLV general anesthesia performed without CO₂ (group NC) or with CO₂ insufflation (group C). The surgical field was graded at thoracoscope introduction and at bulla resection as follows: good (more than half of the 1st rib visible; bleb easily grasped with the stapler), fair (less than half of the 1st rib visible; some manipulation needed to grasp the bleb with the stapler), or poor (1st rib non-visible; bleb ungraspable). Vital signs, arterial blood gas analysis (ABGA), and mechanical ventilation parameters, postoperative chest tube indwelling duration, length of hospital stays, and complications were recorded.

Results

A total of 80 patients were ultimately included. The surgical field at thoracoscope introduction was better in group C (P=0.022). However, at bleb resection, the surgical fields did not differ (P=0.172). The operation time was significantly longer in group C (P=0.019) and anesthesia recovery time was not different (P=0.369). During the CO₂ insufflation, the airway pressure was higher in group C (P=0.009). Mean PaCO₂ was significantly higher (P=0.012) and mean PaO₂ was significantly lower (P=0.024) in group C, but both values were within the physiologically normal range. Postoperative chest tube indwelling duration and length of hospital stays were not statistically different (P=0.234 and 0.085 respectively). Postoperative complication frequencies were similar (12.5% for group NC, 10.0% for group C, P=0.723).

Conclusions

SITS with CO₂ insufflation during ST-TLV did not produce a superior surgical field except at the beginning of surgery. CO₂ insufflation required more time and resulted in higher mean PaCO₂ and peak airway pressure.

The Effects of Secondhand Smoke Exposure on Postoperative Pain and Ventilation Values During One-Lung Ventilation: A Prospective Clinical Trial

OBJECTIVES

To investigate the relationships between secondhand smoke (SHS) exposure and oxygenation during one-lung ventilation (OLV) in lobectomy surgery and between SHS exposure and postoperative analgesic consumption.

DESIGN

Prospective study.

SETTING

University, Faculty of Medicine, operating room.

PARTICIPANTS

Sixty adult patients with American Society of Anesthesiologists score II to III, aged 18 to 65 years, with a body mass index (BMI) <35 kg/m² scheduled for lobectomy surgery by open thoracotomy.

INTERVENTIONS

Patients were divided into 2 groups: the SHS group (n = 30) (urine cotinine level ≥6.0 ng/mL) and the NS (nonsmoker) group (n = 30) (urine cotinine level <6.0 ng/mL and no smoking history). SHS exposure was defined according to a previously published algorithm.

MEASUREMENTS AND MAIN RESULTS

Noninvasive blood pressure, electrocardiography, capnography, and peripheral oxygen saturation were monitored, and intra- and postoperative arterial oxygen tension (PaO₂), arterial carbon dioxide tension (PaCO₂), and intraoperative peak airway pressure were compared between the 2 groups. Postoperative analgesic consumption was calculated. No significant differences in demographics or preoperative data were noted between the 2 groups. PaO₂ values 10 minutes after OLV onset and 10 minutes after the end of OLV were increased significantly in the NS group compared with those in the SHS group (p < 0.05). PaO₂ values after 10 minutes of OLV in the NS and SHS groups were 285.5 ± 90 mmHg and 186.7 ± 66 mmHg, respectively. PaO₂ values after OLV termination in the NS and SHS groups were 365.8 ± 58 mmHg and 283.6 ± 64 mmHg (p < 0.05), respectively. PaCO₂ values 10 minutes after OLV onset, 10 minutes after the end of OLV, at the end of surgery, and upon arrival in the intermediate care unit were significantly different between the 2 groups (p < 0.05).

CONCLUSION

The present study demonstrated that during OLV, patients exposed to SHS exhibited significantly lower arterial oxygen pressure compared with nonsmokers. Arterial carbon dioxide values were increased significantly in SHS-exposed patients. Morphine consumption for postoperative analgesia also was increased in patients exposed to SHS compared with that in nonsmokers.

Anesthetic challenges in minimally invasive cardiac surgery: Are we moving in a right direction?

Continuously growing patient's demand, technological innovation, and surgical expertise have led to the widespread popularity of minimally invasive cardiac surgery (MICS). Patient's demand is being driven by less surgical trauma, reduced scarring, lesser pain, substantially lesser duration of hospital stay, and early return to normal activity. In addition, MICS decreases the incidence of postoperative respiratory dysfunction, chronic pain, chest instability, deep sternal wound infection, bleeding, and atrial fibrillation. Widespread media coverage, competition among surgeons and hospitals, and their associated brand values have further contributed in raising awareness among patients. In this process, surgeons and anesthesiologist have moved from the comfort of traditional wide incision surgeries to more challenging and intensively skilled MICS. A wide variety of cardiac lesions, techniques, and approaches coupled with a significant learning curve have made the anesthesiologist's job a challenging one. Anesthesiologists facilitate in providing optimal surgical settings beginning with lung isolation, confirmation of diagnosis, cannula placement, and cardioplegia delivery. However, the concern remains and it mainly relates to patient safety, prolonged intraoperative duration, and reduced surgical exposure leading to suboptimal treatment. The risk of neurological complications, aortic injury, phrenic nerve palsy, and peripheral vascular thromboembolism can be reduced by proper preoperative evaluation and patient selection. Nevertheless, advancement in surgical instruments, perfusion practices, increasing use of transesophageal echocardiography, and accumulating experience of surgeons and anesthesiologist have somewhat helped in amelioration of these valid concerns. A patient-centric approach and clear communication between the surgeon, anesthesiologist, and perfusionist are vital for the success of MICS.

Thoracoscopic resection of bulky thymoma assisted with artificial pneumothorax: A report of 19 consecutive cases

The aim of the present study was to examine the feasibility and efficacy of thoracoscopic radical resection of large retrosternal thymoma using artificial pneumothorax. A retrospective analysis was performed on 19 patients with bulky thymoma who underwent thoracoscopic resection using artificial pneumothorax by CO₂ insufflation. The operations were performed with unilateral or bilateral thoracic incisions via single lumen endotracheal intubation and two-lung ventilation. This approach provided excellent exposure of the thoracic cavity and reliable control of the neuro-vascular structures in the anterior mediastinum, which was of vital importance for the extended resection of malignant thymoma. The operation time was 140.0±51.4 min without conversion to thoracotomy or sternotomy. The pathological diagnosis was confirmed by immunohistochemistry, including 5 cases of thymus lipomyoma, 1 case of thymus hyperplasia, 1 case of thymus cyst, 2 cases of type AB thymoma, 4 cases of type B1 thymoma, 4 cases of type B3 thymoma, and 2 cases of thymic carcinoma. Furthermore, there were no complications such as recurrent laryngeal nerve injury, phrenic nerve injury, pulmonary infection or atelectasis, with a hospital stay of 5.0±3.0 days. In conclusion, the thoracoscopic resection of thymoma using artificial pneumothorax is a preferable approach, that may be considered for patients with bulky retrosternal tumors.

The "Spacemaker", a New Device for Minimally Invasive Cardiothoracic Surgery: An Evaluation and Feasibility Study

OBJECTIVE

Our aim was to evaluate a new inflatable lung retractor, the "Spacemaker", and its efficacy in facilitating minimally invasive cardiothoracic surgery without the need of one lung ventilation or carbon dioxide overpressure insufflation.

METHODS

The device was tested in 12 anesthetized pigs (90-100 kg) placed on standard endotracheal ventilation. The device was introduced into the right or left side of the chest, depending on the intended procedure to be performed, via a 3-cm incision in the fifth intercostal space. A total of seven animals were used to evaluate hemodynamic and respiratory response to the device, whereas another five animals were used to assess the feasibility of a variety of minimally invasive cardiothoracic surgical procedures.

RESULTS

Introduction was easy and unhindered. The device was inflated up to 0.6 bar, thereby pushing the lung tissue gently away cranially, posteriorly, and caudally without interfering with pulmonary function or resulting in respiratory compromise. In addition, hemodynamics remained stable throughout the experiments. Different closed-chest surgical procedures such as left atrial appendage exclusion, pulmonary vein exposure, pacemaker lead placement, and endoscopic stabilization for coronary surgery, were successfully performed. Removal was quick and complete in all cases, and lung tissue showed no remnant atelectasis.

CONCLUSIONS

The "Spacemaker" may represent a reliable alternative to current conventional techniques to facilitate minimally invasive cardiothoracic surgery. Further research is warranted to confirm the effectiveness and the safety of this device and to optimize the model before its use in humans and its introduction into clinical practice.

Anesthetic issues for robotic cardiac surgery

As innovative technology continues to be developed and is implemented into the realm of cardiac surgery, surgical teams, cardiothoracic anesthesiologists, and health centers are constantly looking for methods to improve patient outcomes and satisfaction. One of the more recent developments in cardiac surgical practice is minimally invasive robotic surgery. Its use has been documented in numerous publications, and its use has proliferated significantly over the past 15 years. The anesthesiology team must continue to develop and perfect special techniques to manage these patients perioperatively including lung isolation techniques and transesophageal echocardiography (TEE). This review article of recent scientific data and personal experience serves to explain some of the challenges, which the anesthetic team must manage, including patient and procedural factors, complications from one-lung ventilation (OLV) including hypoxia and hypercapnia, capnothorax, percutaneous cannulation for cardiopulmonary bypass, TEE guidance, as well as methods of intraoperative monitoring and analgesia. As existing minimally invasive techniques are perfected, and newer innovations are demonstrated, it is imperative that the cardiothoracic anesthesiologist must improve and maintain skills to guide these patients safely through the robotic procedure.

[Thoracoscopic thymectomy with carbon dioxide insufflation in the mediastinum]

The case is presented of a 71 year-old male, diagnosed with a thymoma. A thoracoscopic thymectomy was performed using the carbon dioxide insufflation technique in the mediastinum. During the procedure, while performing one-lung ventilation, the patient's respiration worsened. The contralateral lung had collapsed, as carbon dioxide was travelling from the mediastinum to the thorax through the opened pleura. Two-lung ventilation was decided upon, which clearly improved oxygenation in the arterial gases and airway pressures. Both pH and pCO2 stabilized. The surgical approach and the carbon dioxide technique were continued because 2-lung ventilation did not affect the surgical procedure. This technique has many serious complications and it should always be performed using 2-lung ventilation.

Robotic cardiac surgery: an anaesthetic challenge

Robotic cardiac surgery with the da Vinci robotic surgical system offers the benefits of a minimally invasive procedure, including a smaller incision and scar, reduced risk of infection, less pain and trauma, less bleeding and blood transfusion requirements, shorter hospital stay and decreased recovery time. Robotic cardiac surgery includes extracardiac and intracardiac procedures. Extracardiac procedures are often performed on a beating heart. Intracardiac procedures require the aid of peripheral cardiopulmonary bypass via a minithoracotomy. Robotic cardiac surgery, however, poses challenges to the anaesthetist, as the obligatory one-lung ventilation (OLV) and CO2 insufflation may reduce cardiac output and increase pulmonary vascular resistance, potentially resulting in hypoxaemia and haemodynamic compromise. In addition, surgery requires appropriate positioning of specialised cannulae such as an endopulmonary vent, endocoronary sinus catheter, and endoaortic clamp catheter under the guidance of transoesophageal echocardiography. Therefore, cardiac anaesthetists should have a working knowledge of these systems, OLV and haemodynamic support.

Hypoxemia during one-lung ventilation for robot-assisted coronary artery bypass graft surgery

BACKGROUND

Robot-assisted coronary artery bypass grafting requires continuous one-lung ventilation (OLV) to evacuate the thoracic cavity. Whether this ventilatory mode subjects patients to serious hypoxemia remains underinvestigated.

METHODS

From 2005 to 2010, all patients receiving robot-assisted coronary artery bypass graft surgery using OLV with active capnothorax for internal mammary artery harvesting and then passive pneumothorax for minithoracotomy direct-vision coronary bypass graft surgery were included. Patients' variables of oxygenation were monitored and compared throughout the whole surgical period. Persistent oxygen desaturation (arterial oxygen pressure <70 mm Hg) refractory to primary managements was defined as a hypoxemic event, and predictors of such events were identified by multivariate regression analysis.

RESULTS

A total of 255 consecutive patients were enrolled. Average oxygen saturation decreased modestly during the first stage of OLV with active capnothorax, causing hypoxemic events in 9 patients (4.3%) leading to death in 2 (0.8%), whereas it dropped drastically in the second stage of OLV with passive pneumothorax, resulting in hypoxemic events in 32 patients (12.6%) and death in 1 (0.4%). Multivariate regression analysis identified high pulmonary vascular resistance and low left ventricular ejection fraction as predictors of hypoxemia during internal mammary artery takedown, whereas prolonged procedure and chronic obstructive pulmonary disease were identified as predictors during minithoracotomy bypass grafting.

CONCLUSIONS

Robot-assisted two-stage coronary artery bypass surgery employing OLV could be complicated by serious hypoxemia especially at the minithoracotomy grafting stage and in patients with specific risk factors. Thus, when managing such patients, invasive monitoring and aggressive treatment of arterial desaturation are mandatory to ensure the patient's safety and procedural smoothness.

Managing hypoxemia during minimally invasive thoracic surgery

An ever-increasing number of thoracic procedures are being performed through minimally invasive techniques. Although the incidence of hypoxemia during one-lung ventilation (OLV) has decreased over the years, it remains an issue in roughly 10% of cases. Algorithms for the management of OLV hypoxemia have to be adapted to the thoracoscopic approach, in particular the need for optimal surgical exposure. With appropriate planning and caution, most of the treatment modalities for OLV hypoxemia can be applied to the thoracoscopy setting, with some modifications.

Right or left first during bilateral thoracoscopy?

BACKGROUND

Endoscopic thoracic sympathectomy (ETS) is now an established surgical technique for treatment of palmar hyperhidrosis that is performed under general anesthesia with positive pressure ventilation via either an endotracheal tube or a double lumen endobronchial tube. This is a bilateral disease that requires the division of the right and left thoracic sympathetic chain. The aim of this study was to compare the hemodynamic changes using a left capnothorax first versus right a capnothorax first surgical approach using a single lumen endotracheal tube in patients undergoing bilateral ETS. Lung collapse was achieved by carbon dioxide insufflation.

METHODS

Forty patients of both sexes aged 18-30 years and of American Society of Anesthesiologists grade I were randomly assigned to undergo bilateral ETS. Patients were divided into two groups. Group L comprised left capnothorax first, followed by right capnothorax (n = 20). Group R comprised right capnothorax first, followed by left capnothorax (n = 20). The anesthesia technique was standardized for all patients. Cardiovascular variables were determined during the procedure every minute. Statistical analysis was performed by independent-sample t test and Pearson's chi-square test.

RESULTS

There was a significant (P < 0.05) mean percentage decrease in systolic blood pressure in group L compared to group R. Similarly, the mean percentage decrease in diastolic blood pressure in group L was significant compared to group R (P < 0.05). Seven patients in group L developed bradycardia, but this was not found to be statistically significant.

CONCLUSIONS

When the left capnothorax first approach was used, there was significant hypotension, compared to a right capnothorax first thoracoscopy. We thus recommend that right capnothorax should be performed first in cases of bilateral ETS.

Risk of renal dysfunction after less invasive multivessel coronary artery bypass grafting

OBJECTIVE

Several centers have established that off-pump, multivessel coronary artery bypass grafting performed via a small thoracotomy (MVST) is feasible. However, this procedure can be challenging when posterolateral coronary targets need to be grafted. We hypothesized that use of cardiopulmonary bypass via peripheral access (MVST-PA) would improve outcomes compared with a completely off-pump approach (OP-MVST).

METHODS

This was a prospective observational study of patients undergoing OP-MVST (n = 46) versus MVST-PA (n = 45) using bilateral internal mammary artery grafts onto the left anterior descending coronary artery and circumflex/right coronary artery distribution. Hemostasis was quantified by measuring platelet function (aggregometry), chest tube output, thrombolysis in myocardial infarction bleeding score (%hematocrit change at 24 hours), and transfusion requirements. The rate of mortality and major morbidity at 30 days was defined according to The Society of Thoracic Surgeons criteria. Estimated glomerular filtration rate (normalized to baseline levels) was determined daily until discharge.

RESULTS

The OP-MVST versus MVST-PA groups had similar risk factors at baseline and risks of composite morbidity/mortality at 30 days. However, renal failure was significantly increased after OP-MVST (10.87 vs 0%, P = 0.05), and MVST-PA affected hemostasis as evidenced by inhibition of platelet function (latency to response on aggregometry, 29.9 vs 17.9 seconds; P = 0.04) and higher transfusion requirement (2.31 vs 0.85 units of red blood cells/patient, P = 0.04; 55.6% vs 34.8% transfused; P = 0.059). However, 24-hour chest tube output was similar (645 vs 750 mL; P = 0.53).

CONCLUSIONS

In comparison with a completely off-pump strategy, use of cardiopulmonary bypass to assist MVST reduced the risk of renal dysfunction with only modest tradeoffs in other morbidities, for example, altered coagulation and higher transfusion requirements. These data justify further study of the effect of MVST-PA on renal complications.

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.

Anesthetic management of the patient with dilated cardiomyopathy undergoing pulmonary resection surgery: a case-based discussion

Interactions between the cardiovascular and respiratory systems are complex and profound. General anesthesia, muscle relaxation, and positive-pressure ventilation all impose physiological effects on cardiovascular function. In patients presenting for pulmonary resection, additional effects resulting from positioning, 1-lung ventilation, surgical procedures, and contraction of the pulmonary vascular bed may impose an additional physiological burden. For most patients with adequate pulmonary and cardiovascular reserve, these effects are well tolerated. However, the cardiothoracic anesthesiologist may be asked to provide anesthetic care for patients with significantly reduced cardiac function who require potentially curative pulmonary resection for lung cancer. These patients present a major perioperative challenge and a thoughtful approach to intraoperative management is required. The authors review a case of a patient with severely impaired biventricular function who presented for elective pulmonary lobectomy in an attempt to effect a curative resection of lung cancer and present a discussion of physiological and pathophysiological considerations for clinical management.

Single-lung ventilation with carbon dioxide hemipneumothorax: hemodynamic and respiratory effects in piglets

OBJECTIVES

Video-assisted thoracoscopic surgery (VATS) has become a standard procedure in pediatric surgery. To facilitate surgical access, the dependent lung has to collapse using intrathoracic carbon dioxide insufflation and/or single-lung ventilation. These procedures can induce hemodynamic deteriorations in adults. The potential impacts of single-lung ventilation in combination with capnothorax on hemodynamics in infants have never been studied before.

AIM

We conducted a randomized experimental study focusing on hemodynamic and respiratory changes during single-lung ventilation with or without capnothorax in a pediatric animal model.

METHODS

Twelve piglets were randomly assigned to receive single-lung ventilation with (SLV-CO(2) ) or without (SLV) capnothorax with an insufflation pressure of 5 mmHg for a period of two hours. Before, during, and after single-lung ventilation, hemodynamic and respiratory parameters were measured.

RESULTS

Although mean arterial pressure remained stable during the course of the study and no critical incidents were monitored, cardiac index (CI) decreased significantly with SLV-CO(2) (baseline 3.6 ± 1.6 l · min(-1) · m(-2) vs 2.9 ± 1.1 l · min(-1) · m(-2) at 120 min, P < 0.05). Furthermore, global end-diastolic volume and intrathoracic blood volume (ITBV) decreased as well significantly with SLV-CO(2) , causing a significant between-group difference in ITBV (P < 0.05).

CONCLUSIONS

Despite a decrease in CI and preload parameters, the combination of single-lung ventilation and low-pressure capnothorax was well tolerated in piglets and could justify further clinical studies to be performed in infants and children focusing on hemodynamic and respiratory changes during VATS.

Asystole following positive pressure insufflation of right pleural cavity: a case report

INTRODUCTION

Adverse hemodynamic effects with severe bradycardia have been previously reported during positive pressure insufflation of the right thoracic cavity in humans. To the best of our knowledge, this is the first report of asystole during thoracoscopic surgery with positive pressure insufflation.

CASE PRESENTATION

A 63-year-old Caucasian woman developed asystole at the onset of positive pressure insufflation of her right hemithorax during a thoracoscopic single-lung ventilation procedure. Immediate deflation of pleural cavity, intravenous glycopyrrolate and atropine administration returned her heart rhythm to normal sinus rhythm. The surgery proceeded in the absence of positive pressure insufflation without any further complications.

CONCLUSIONS

We discuss the proposed mechanisms of hemodynamic instability with positive pressure thoracic insufflation, and anesthetic and insufflation techniques that decrease the likelihood of adverse hemodynamic events.

Cardiac preload: hemodynamic physiology during thoracic surgery

PURPOSE OF REVIEW

Operations in pleural cavity have circulatory effects both in pulmonary and systemic circulations. Nevertheless studies of these effects have yielded conflicting results. The importance of good understanding of hemodynamic changes during the operation in pleural cavity consists in fact that they are one of the factors influencing postoperative course of operated patients.

RECENT FINDINGS

Dominating changes in the hemodynamics are represented by an increase of the cardiac output after opening the pleura. Changes in the arterial pressure are clinically unimportant and decreased cardiac output cannot be explained by preload as the preload is almost constant during the whole operation procedure. Arterial pressures in the pulmonary circulation are also increased after opening of pleura but only in the hip position so it depends on the body position rather than on the operation itself.

SUMMARY

As far as it is known, circulatory and ventilatory consequences of thoracotomy are influenced particularly by the position of the patient's body on the operation table. During operation performed on the lung hemodynamics are influenced particularly by the individual steps of the operation procedure and by the position of the body. The hemodynamics are also influenced by metabolic functions of lungs particularly by the increased turnover of catecholamines in the lungs (increased total peripheral resistance and arterial pressures).

Mediastinoscopy and Video-Assisted Thoracoscopic Surgery: Anesthetic Pitfalls and Complications

Endoscopic evaluation of the thoracic cavity was first described in 1910 when Jacobaeus used a cystoscope for pleural examination. Significant advances in thoracoscopic surgery, including the use of high-definition videoscopy and refinements in surgical technique, have created a vast array of increasingly complex procedures that can be performed. The minimally invasive nature of video-assisted thoracoscopic surgery (VATS) makes it ideal for diagnostic and therapeutic procedures in ambulatory and critically ill patients. Mediastinoscopy is often performed immediately preceding VATS to permit sampling of mediastinal lymph nodes. As the indications for thoracoscopic surgery expand, the anesthesiologist must be familiar with common anesthetic and surgical complications, which occur in up to 9% of patients.

Video assisted thoracic surgery in the management of spontaneous pneumothorax: the current status

Over the past decade, video assisted thoracic surgery (VATS) has changed the way spontaneous pneumothorax (SP) is managed. Benefits of VATS include less postoperative pain, shorter hospital stay, and attenuated postoperative inflammatory response are evident compared with open thoracic procedures. Furthermore, the increasing acceptance by patients and referring physicians is testament to its success. Recent studies and the authors decade of experience in management of SP by VATS show that it is quick, safe, and effective, with recurrence rates generally comparable to open procedures, with some exceptions. However, selecting the correct procedure and patient, as well as knowing the limitations of the surgeons and techniques are paramount for success. Even to this day, there are considerable variations in the treatment of SP and large scale controlled studies are needed to better define timing of surgery and the role of the different procedures in the treatment and prevention of SP.

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.

Video-assisted thoracoscopic surgery (VATS) bullectomy for emphysematous/bullous lung disease

Video-assisted thoracic surgery (VATS) is now considered by many to be the approach of choice in bullectomy. We present our technique below.

Cardiovascular changes during drainage of pericardial effusion by thoracoscopy

BACKGROUND

Cardiovascular changes during drainage of pericardial effusion are not well understood, and most studies are of systemic effects and not of right ventricular performance. Thoracoscopy is not widely used to drain pericardial effusions because of haemodynamic changes in relation to the use of single lung ventilation.

PATIENTS AND METHODS

We studied 16 patients undergoing partial pericardiectomy for pericardial effusion, using videothoracoscopy with a low-pressure pneumothorax (6 mm Hg). Cardiac output was measured by thermodilution with the patient anaesthetized in the supine position before the procedure; in the right lateral position after a low-pressure pneumothorax had been established; and after drainage of the pericardial effusion.

RESULTS

Before the procedure, cardiac output was low and central venous pressure and pulmonary artery occlusion pressure were increased. Systemic vascular resistance and arterial blood pressure were within normal limits. Cardiac filling pressure and pulmonary arterial pressure increased during the pneumothorax. After the drainage cardiac index increased and systemic and pulmonary vascular resistances were reduced.

CONCLUSIONS

Pericardial effusion reduces right ventricular distensibility, right and left systolic ventricular function, and cardiac output. Anaesthesia with mechanical ventilation and a low-pressure pneumothorax do not affect the circulation greatly. Drainage of the pericardial effusion allows cardiac distensibility to increase and cardiac performance changes to allow increased ejection.

Effect of one-lung ventilation on oxygen delivery in anesthetized dogs with an open thoracic cavity

OBJECTIVE

To evaluate effects of one-lung ventilation on oxygen delivery in anesthetized dogs with an open thoracic cavity.

ANIMALS

8 clinically normal adult Walker Hound dogs.

PROCEDURE

Each dog was anesthetized and subjected to one-lung ventilation during a period when it had an open thoracic cavity. A Swan-Ganz catheter was used to measure hemodynamic variables and obtain mixed-venous blood samples. A catheter was inserted in the dorsal pedal artery to measure arterial pressure and obtain arterial blood samples. Oxygen delivery index was calculated and used to assess effects of one-lung ventilation on cardiopulmonary function. Effects on hemodynamic and pulmonary variables were analyzed.

RESULTS

One-lung ventilation caused significant decreases in PaO2, arterial oxygen saturation (SaO2), mixed-venous oxygen saturation, and arterial oxygen content (CaO2). One-lung ventilation caused significant increases in PaCO2, physiologic dead space, and alveolar-arterial oxygen difference. Changes in SaO2, CaO2, and PaCO2, although significantly different, were not considered to be of clinical importance. One-lung ventilation induced a significant increase in pulmonary arterial wedge pressure, mean pulmonary artery pressure, and shunt fraction. One-lung ventilation did not have a significant effect on cardiac index, systemic vascular resistance index, pulmonary vascular resistance index, and oxygen delivery index.

CONCLUSIONS AND CLINICAL RELEVANCE

One-lung ventilation affected gas exchange and hemodynamic function, although oxygen delivery in clinically normal dogs was not affected during a period with an open thoracic cavity. One-lung ventilation can be used safely in healthy dogs with an open thoracic cavity during surgery.