Clinical Research Directory

Mechanical Power in One-lung Ventilation

Thoracic surgery usually necessitates one-lung ventilation (OLV) to provide surgical access while maintaining adequate gas exchange. However, OLV is associated with an increased risk of PPCs , a major cause of morbidity and mortality. Mechanical power, a composite parameter incorporating tidal volume, respiratory rate, driving pressure, and flow resistance, has been proposed as a key factor influencing ventilator-induced lung injury (VILI) and postoperative outcome. Understanding the association between mechanical power during OLV and PPCs could provide insights for optimizing intraoperative ventilatory strategies and reducing the burden of PPCs. As OLV inherently alters normal lung mechanics by decreasing functional residual capacity and introducing inequalities in ventilation-perfusion ratio, the complexity of managing mechanical power becomes even more pronounced. Under these altered conditions, the risk of PPC-including atelectasis, pneumonia, and respiratory failure-can be significantly elevated. Factors such as ventilatory settings, lung protection strategies, and the duration of OLV play pivotal roles in influencing mechanical power delivery and thereby impacting lung function recovery post-surgery. Current literature indicates a correlation between inappropriate mechanical ventilation strategies during OLV and increased incidence of PPCs. However, there remains a gap in understanding how precisely mechanical power, as a quantifiable measure, influences patient outcomes following OLV. Therefore, this study aims to investigate the relationship between mechanical power during OLV and the subsequent risk of PPC. By elucidating these dynamics, the findings may inform clinical practices surrounding OLV management, ultimately improving patient safety and outcomes in thoracic surgery.

The Effect of Single Lung Ventilation Duration and Intraoperative Brain Oxygenation on Cognitive Function and Postoperative Pain in Geriatric Patients

One lung ventilation (OLV) is commonly used in thoracic surgery. Although the lack of ventilation of the lung in the surgical area (independent lung) during OLV redirects pulmonary blood flow to the dependent lung, shunt development is inevitable, and consequently, hypoxia is a frequently encountered condition. Therefore, one of the most important aspects that clinicians pay attention to during OLV is cerebral oxygen saturation in addition to peripheral oxygenation monitoring. Studies have shown a correlation between decreased cerebral oxygen saturation and postoperative cognitive dysfunction (POCD). Patients undergoing OLV are also at risk of cerebral desaturation due to this non-physiological ventilation. Patients undergoing OLV are at risk of cerebral oxygen desaturation. Therefore, in these patients, both cognitive dysfunction and changes in brain oxygenation can negatively affect pain-related centers, altering pain perception. Geriatric patients are particularly more affected by these negative effects. It is generally accepted by healthcare professionals specializing in pain management that the application of pain management should differ for elderly patients compared to younger patients. Analgesic dose adjustment should be done more carefully in geriatric patients. Increased sensitivity to opioids due to hypoxia can cause respiratory depression and increased analgesic effects. To avoid these, opioid dose adjustment is necessary in these patients. In conclusion, cerebral oxygen saturation measurement can be an effective method to detect cerebral oxygen desaturation, especially in the geriatric patient group. In this way, the effect of hypoxia caused by OLV on cerebral oxygen saturation can be detected early, and POCD can be limited. We believe that this situation can also contribute to effective postoperative pain management. This study aimed to investigate the effect of intraoperative brain oxygenation on cognitive function and postoperative pain in geriatric patients who underwent OLV. MATERİAL AND METHODS This study will be conducted in accordance with the Helsinki Declaration and will take place at Health Sciences University Ankara Atatürk Sanatorium Training and Research Hospital . The study will be planned for geriatric patients over 65 years of age with a high school diploma or higher education level who have given informed consent and are scheduled for OLV with standard anesthesia monitoring. These patients, undergoing thoracic surgery via thoracotomy and who agree to participate in this study and sign an informed consent form, will be prospectively enrolled. A total of 30 patients will be included in our study. Preoperatively, patients will undergo standard monitoring including non-invasive arterial blood pressure, electrocardiography, and peripheral oxygen saturation (SpO2). Cerebral oxygenation of patients who have signed an informed consent form the day before will be recorded throughout the surgical procedure using probes placed on the forehead before the induction of anesthetic drugs. The standard anesthesia and analgesia protocol that we routinely apply to patients will be applied throughout the surgery. Routine preoperative blood tests, age, height, weight, Body Mass Index (BMI), gender, diagnosis, preoperative comorbidities (hypertension, diabetes, coronary artery disease, chronic obstructive pulmonary disease, etc.), previous surgeries (any surgical procedure performed under general anesthesia before this study), American Society of Anesthesiologists ( ASA) score, and duration of surgery will be recorded for each patient. Hemodynamic data (systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), pulse, SpO2, and cerebral oxygen saturation will be recorded before anesthesia induction, after induction, and at 5, 10, 20, 30, and 60 minutes after the start of OLV. These hemodynamic data will also be recorded at the end OLV and at the end of the operation. OLV duration, anesthesia duration, surgery duration, amount of fluid administered, urine output, and whether blood replacement was performed will be recorded. Visual Analog Scale (VAS) scores will be recorded at 1, 2, 4, 8, 16, and 24 hours postoperatively. Analgesic medications administered during the 24-hour postoperative period will also be recorded. VAS evaluation will be performed on a 100 mm scale, where 0: no pain and 100: maximum pain, indicating the patient's pain level. During this process, any possible side effects that may develop due to analgesic treatment will be recorded. The Mini Mental Test (MMT) form will be completed by patients one day before surgery, 48 hours postoperatively, on the 7th day postoperatively. MMT consists of eleven items grouped under five main headings: Orientation, recording memory, attention and calculation, recall, and language, and is evaluated out of a total score of 30.

Opioid Consumption After Thoracotomy and Factors Affecting Postoperative Acute Pain

Thoracic surgery operations constitute a significant portion of surgical procedures performed in hospitals. In the United States, more than 50,000 thoracic surgical procedures are performed annually, and more than 80% of these patients experience moderate to severe postoperative pain requiring opioid administration, which increases the risk of complications . It has also been reported that chronic pain develops in approximately 50% of patients after thoracic surgery . Thoracic surgery is commonly associated with severe, multifactorial pain during the postoperative period and is among the surgical branches with a high risk of developing chronic pain Despite advances in understanding postoperative pain mechanisms and improvements in pain management, inadequate postoperative pain control remains an unresolved healthcare problem. Higher acute pain scores are associated with less effective ventilation and coughing, increased incidence of lower respiratory tract infections, and prolonged ICU and hospital stays . In the management of acute postoperative pain after thoracic surgery, clinicians have sought alternatives to thoracic epidural analgesia to avoid its potential adverse effects. Truncal blocks such as thoracic paravertebral block, erector spinae plane block, and serratus anterior block have been used to reduce postoperative pain . Additionally, various other analgesic techniques such as patient-controlled analgesia (PCA) and multimodal analgesia have been employed. Historically, the cornerstone of acute postoperative pain control has been systemic opioids administered via oral, intravenous, or thoracic epidural routes . Although opioids provide excellent pain relief, they are associated with significant side effects that can adversely affect recovery . With the increasing use of ultrasonography (USG), truncal blocks have become more widespread. Alongside the development of Enhanced Recovery After Thoracic Surgery (ERATS) protocols, efforts have been made to reduce opioid use, leading to differing opinions regarding the management of acute pain after thoracic surgery. To prevent opioid use disorder and potential side effects, opioid-free or opioid-sparing approaches are now being encouraged in perioperative pain management . Conversely, some studies suggest that intraoperative opioid administration may have favorable effects on postoperative acute and chronic pain. Previous research has reported that the average daily opioid consumption after thoracic surgery is approximately 30 morphine milligram equivalents (MME) . Although video-assisted thoracoscopic surgery (VATS) has become more common, thoracotomy cases still constitute a large proportion of thoracic surgery procedures. Moreover, severe postoperative pain after thoracic surgery is most commonly associated with the thoracotomy incision itself. While some studies have suggested that new truncal block techniques may provide effective analgesia and reduce opioid consumption after thoracotomy, further studies are needed to determine which blocks are most commonly preferred and how opioid consumption patterns have changed with the adoption of these newer regional techniques. A review of the current literature reveals that the factors influencing acute pain after thoracotomy have not been sufficiently evaluated. Therefore, a re-evaluation of the factors affecting acute pain following thoracotomy, considering recent developments in pain management, is necessary. Furthermore, examining the relationship between perioperative opioid consumption, postoperative complications, and hospital length of stay in this patient population will provide valuable contributions to the literature. The aim of this study is to evaluate the amount of opioid consumption following thoracotomy and to investigate whether perioperative opioid use affects acute pain, postoperative complications, and the length of hospital stay.

The Role of Existing Formulas in the Double-lumen Tube in Thoracic Surgery Anesthesia

In most clinical scenarios, left DLT is preferred for one-lung ventilation because of its anatomical ease of placement; these tubes allow separate ventilation of both lungs. If the DLT is not placed in the proper size and depth, it may result in repeated intubation attempts, airway and dental trauma, failed lung isolation, tube dislodgement, and various unwanted events such as hypoxemia. The first and most common method for correct placement of a DLT is the conventional technique, blindly advanced into the left main bronchus, and then confirmed with fiberoptic bronchoscopy (FOB). In this method, the depth at which the tube should be left before performing FOB is left to the clinician's experience. Generally, the DLT is advanced in the trachea until a slight resistance is felt. This may lead to excessive advancement of the DLT into the left main bronchus or premature resistance due to the tube tip touching the carina, causing the clinician to stop before entering the left main bronchus. Therefore, just as selecting the correct size of the DLT is crucial, correctly estimating the appropriate depth is also of great importance. For this reason, different formulas have been proposed in the literature, and new formulas are still being investigated. The patient's gender and height are determinant in selecting the appropriate size of the DLT. However, studies in the literature indicate that the accuracy of these formulas may be limited in Asian populations. Therefore, it is important to evaluate the applicability of these formulas in different populations and, if necessary, develop new formulas. In the Turkish population as well, verifying the accuracy of these formulas for determining the proper size and depth of DLT-and if needed, developing new recommendations and formulas-holds clinical importance. In this study, conducted at Ankara Atatürk Sanatorium Training and Research Hospital, the aim is to evaluate the accuracy of six different formulas available in the literature for predicting DLT depth in patients undergoing thoracic surgery. Additionally, the correlations between DLT depth and demographic parameters as well as external airway measurements (mouth opening, sternomental distance, thyromental distance, distance between the mentum and manubrio-sternal angle, distance between tragus and manubrio-sternal angle, distance between sternal angle and xiphoid process) will be analyzed. Furthermore, challenges during DLT application, malposition rates and types, and complications will be assessed. The primary objective of this study is to evaluate, in patients undergoing thoracic surgery at Ankara Atatürk Sanatorium Training and Research Hospital, how accurate and applicable six different formulas defined in the literature are for predicting the placement depth of the DLT. If the existing formulas are insufficient, the aim is to develop a new formula.