Associations among preoperative transthoracic echocardiography variables and cerebral near-infrared spectroscopy values at baseline before anesthesia in patients undergoing cardiac surgery: a retrospective observational study.

Cerebral tissue oximetry with near-infrared spectroscopy (NIRS) is used to monitor cerebral oxygenation during cardiac surgery. To date, reduced baseline cerebral NIRS values have been attributed to reduced cerebral blood flow primarily based on a significant positive correlation between left ventricular ejection fraction (LVEF) and baseline rSO2 measured with the INVOS 5100C oximeter. Reportedly, however, rSO2, but not StO2 measured with the FORESIGHT Elite oximeter, correlated with LVEF. We, thus, investigated associations among baseline NIRS values measured with three different oximeters before anesthesia for cardiac surgery and preoperative transthoracic echocardiography (TTE) variables, including LVEF, to examine whether there are inter-device differences in associations among baseline NIRS values and TTE variables. Using Spearman's correlation coefficient, we retrospectively investigated associations among 15 preoperative TTE variables, including LVEF, and baseline NIRS values, including rSO2, StO2, and TOI with the NIRO-200NX oximeter in 1346, 515, and 301 patients, respectively. Only rSO2 (p < 0.00001), but not TOI or StO2 (p > 0.05), positively correlated with LVEF. On the other hand, baseline rSO2, TOI, and StO2 consistently, negatively correlated with the left atrial diameter index (LADI), early diastolic transmitral flow velocity (E), E-to-early diastolic mitral annular velocity ratio (E/e'), estimated right ventricular systolic pressure (eRVP), and inferior vena cava diameter index (IVCDI) (p < 0.0005 to p < 0.00001). Because all of these five TTE variables could be positively associated with right as well as left ventricular filling pressure, our results indicated that reduced baseline NIRS values were consistently associated not with reduced LVEF but with TTE findings indicative of elevated biventricular filling pressure. Our data suggest that regional venous congestion greatly contributes to reduced baseline NIRS values in patients undergoing cardiac surgery.

Effects of the Multidisciplinary Preoperative Clinic on the Incidence of Elective Surgery Cancellation.

To evaluate effects of the multidisciplinary preoperative clinic (POC) consisting of anesthesiologists, dentists, pharmacists, and nurses on elective surgery cancellation, we retrospectively investigated patients who underwent elective non-cardiac, non-obstetric surgeries between October, 2018 and March, 2019 (before the POC establishment: Group 1) and between October, 2019 and March, 2020 (after the POC establishment: Group 2). Among reasons for surgery cancellation allocated into eight categories, three reasons for cancellation (related to consent authorization, medication, and significant comorbidities) were considered preventable. We compared incidences of overall and preventable cancellations of surgeries between 4,198 patients in Group 1 and 4,664 patients in Group 2, who had significantly different clinical backgrounds, including the ASA-PS class. There was no significant difference in the incidence of overall cancellation between Group 1 and Group 2 (4.1% vs. 4.1%, p = 0.96). However, the incidence of preventable cancellation was significantly lower in Group 2 than in Group 1 (0.4% vs. 0.7%, p = 0.045). In addition, the incidence of overall cancellation was significantly lower in 3,741 Group 2 patients visiting the POC than in 5,121 patients not visiting the POC in both Groups (3.2% vs. 4.7%, p < 0.001). Further, in 3,423 pairs of patients with comparable clinical backgrounds created from both Groups using propensity score matching, incidences of overall cancellation (2.2% vs. 3.1%) and preventable cancellation (0.1% vs. 0.6%) were significantly lower in Group 2 than in Group 1 (p = 0.036 and 0.008, respectively). In conclusion, the multidisciplinary POC was effective in reducing elective surgery cancellation.

Effects of alveolar recruitment maneuver on end-expiratory lung volume during one-lung ventilation.

PURPOSE: To investigate the effects of alveolar recruitment maneuver (ARM) during one-lung ventilation (OLV) on end-expiratory lung volume (EELV) of the dependent lung. METHODS: Patients who were planned to undergo lung resection surgery for lung tumors and needed OLV for at least 1 h were included in the study. After turning the patients into the lateral position under total intravenous anesthesia, OLV was commenced using a double-lumen endobronchial tube. EELV was measured using the nitrogen washout technique at 20 min after OLV started (baseline) and 15, 30, 45, 60 min after ARM was performed on the dependent lung. RESULTS: Among 42 patients who completed the study, EELV increased at 15 min after ARM by 20% or greater compared with baseline in 21 patients (responders). Responders were significantly shorter in height (158 vs. 165 cm, p = 0.01) and had smaller preoperative functional residual capacity (2.99L vs. 3.65L, p = 0.02) than non-responders. Before ARM, responders had significantly higher driving pressure (14.2 vs. 12.4 cmH2O, p = 0.01) and lower respiratory system compliance (23.6 vs. 31.4 ml/cmH2O, p = 0.0002) than non-responders. Driving pressure temporarily dropped after ARM in responders, while no significant change was observed in non-responders. Fourteen out of 21 responders kept EELV 20% or more increased EELV than baseline at 60 min after ARM. CONCLUSION: EELV of the dependent lung was increased by 20% or greater in half of the patients responding to ARM. The increased volume of the dependent lung caused by ARM was maintained for 60 min in two-thirds of the responders.

Endoscopic laryngo-pharyngeal surgery for superficial laryngo-pharyngeal cancer.

BACKGROUND AND STUDY AIMS: Narrow band imaging (NBI) combined with magnifying endoscopy enables us to detect superficial laryngo-pharyngeal cancers, which are difficult to detect by standard endoscopy. Endoscopic laryngo-pharyngeal surgery (ELPS) is a technique developed to treat such lesions and the purpose of this study is to evaluate the usefulness of ELPS for superficial laryngo-pharyngeal cancer. PATIENTS AND METHODS: Seventy five consecutive patients with 104 fresh superficial laryngo-pharyngeal cancers are included in this study. Under general anesthesia, a specially-designed curved laryngoscope was inserted to create a working space in the pharyngeal lumen. A magnifying endoscope was inserted transorally to visualize the field and a head & neck surgeon dissected the lesion using the combination of the orally-inserted curved grasping forceps and electrosurgical needle knife in both hands. The safely, functional outcomes, and oncologic outcomes of ELPS were evaluated retrospectively. RESULTS: Median operation time per lesion was 35 min. Post-operative bleeding occurred in 3 cases and temporal subcutaneous emphysema occurred in 10 cases. No vocal fold impairment occurred after surgery. The median fasting period was 2 days and all patients except one have a normal diet with no limitations. Local recurrence occurred in 1 case, and the 3-year overall survival rate and the 3-year disease specific survival rate was 90% and 100%, respectively. CONCLUSIONS: ELPS is a hybrid of head and neck surgery and gastrointestinal endoscopic treatment, and enjoys the merit of both procedures. ELPS makes it possible to perform minimally-invasive surgery, preserving both the swallowing and phonation functions.

Efficacy of Supraglottic Airway for Preventing Lung Injury Associated with Coughing at Extubation after Pulmonary Lobectomy.

BACKGROUND: The use of double-lumen endobronchial tubes (DLTs) is necessary for differential lung ventilation during pulmonary lobectomy. However, when used with conventional extubation procedures, coughing is more likely and is associated with an increased risk for parenchymal air leak along the staple line and possible subsequent lung injury. We examined the prevalence of coughing-associated air leaks at extubation and the efficacy of using supraglottic airways (SGAs) to prevent air leaks with post-lobectomy extubation. METHODS: This study included 150 patients with pulmonary emphysema diagnosed using preoperative computed tomography, who underwent pulmonary lobectomy between April 2010 and March 2015. The patients were chronologically enrolled in two groups: the DLT group (60 patients) from April 2010 to August 2012, and the SGA group (90 patients) from September 2012 to March 2015. (Note: the DLT group only included cases without air leak present just prior to extubation). Data were collected on specific patient characteristics and operative and postoperative factors. RESULTS: Coughing at extubation occurred in 15 (25.0 %) of 60 DLT patients, and parenchymal air leaks developed in 10 (66.7 %) of these 15. Comparison of groups revealed the SGA group was significantly lower for the following: patients with coughing at extubation (P < 0.001), coughing-associated air leaks at extubation (P < 0.001), air leaks >7 days (P = 0.006), reoperation due to air leaks (P = 0.013), and duration of chest tube drainage (P < 0.001). CONCLUSIONS: The SGA is effective for preventing air leaks associated with coughing during conventional DLT extubation in post-lobectomy patients.

Perioperative risk factors for acute kidney injury after liver resection surgery: an historical cohort study.

PURPOSE: This study aimed to identify the incidence and risk factors for acute kidney injury (AKI) after liver resection surgery and to clarify the relationship between postoperative AKI and outcome. METHODS: We conducted a historical cohort study of patients who underwent liver resection surgery with sevoflurane anesthesia from January 2004 to October 2011. Acute kidney injury was diagnosed based on the Acute Kidney Injury Network classification within 72 hr after the surgery. Patient data, surgical and anesthetic data, and laboratory data were extracted manually from the patients' electronic charts. Multivariable logistic regression analysis was used to identify perioperative risk factors for postoperative AKI. RESULTS: Acute kidney injury was diagnosed in 78 of 642 patients (12.1%; 95% confidence interval [CI]: 9.7 to 14.9). Multivariable analysis showed an independent association between postoperative AKI and preoperative estimated glomerular filtration rate (adjusted odds ratio [aOR] 0.74; 95% CI: 0.64 to 0.85), preoperative hypertension (aOR 2.10; 95% CI: 1.11 to 3.97), and intraoperative red blood cell transfusion (aOR 1.04; 95% CI: 1.01 to 1.07). Development of AKI within 72 hr after liver resection surgery was associated with increased hospital mortality, prolonged length of stay, and increased rates of mechanical ventilation, reintubation, and renal replacement therapy. CONCLUSION: Perioperative risk factors for AKI after liver resection surgery are similar to those established for other surgical procedures. Further studies are needed to establish causality and to determine whether interventions on modifiable risk factors can reduce the incidence of postoperative AKI and improve patient outcome. This study was registered at the University Hospital Medical Information Network (UMIN) Center (UMIN 000008089).

Perioperative management of carinal pneumonectomy: a retrospective review of 13 patients.

Carinal pneumonectomy is a challenging procedure because of the difficulties in surgical technique, intraoperative airway management, and postoperative respiratory and anastomotic complications. However, information regarding the anesthetic and intraoperative respiratory management of this procedure is scarce. This report describes our routine anesthetic and respiratory management strategy in patients undergoing carinal pneumonectomy. Medical records of 13 patients who underwent carinal pneumonectomy under combined general and epidural anesthesia between 2008 and 2012 were analyzed retrospectively. Eleven patients underwent right carinal pneumonectomy and two underwent left carinal pneumonectomy. A left double-lumen tube was used in all but one case, in which endobronchial intubation was difficult because of intrabronchial invasion of the tumor. A 6.0-mm-long reinforced endobronchial tube was intubated into the main bronchus of the non-operative side from the surgical field during carinal resection. There were no episodes of severe hypoxemia or hypercapnia during surgery. Twelve patients were extubated immediately after surgery. No patient developed post-thoracotomy acute lung injury or required postoperative reintubation despite poor preoperative respiratory function. The 30-day mortality rate was 0%. Our airway management protocol for carinal pneumonectomy enables positive surgical outcomes.

Acute kidney injury within 72 hours after lung transplantation: incidence and perioperative risk factors.

OBJECTIVE: To define the incidence and perioperative risk factors of acute kidney injury (AKI) within 72 hours after lung transplantation and clarify the relationship between postoperative AKI and outcome in patients undergoing lung transplantation. DESIGN: A retrospective observational study. SETTING: A tertiary care academic center. PARTICIPANTS: Fifty-four patients who underwent lung transplantation between January 2006 and March 2010. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: After excluding 4 patients who died or required additional surgery during the first 72 hours after transplantation, 50 patients were included in the final analysis. Data were extracted from medical charts and electronic health record information system. Risk, injury, failure, loss, endstage (RIFLE) renal disease creatinine criteria were used for the diagnosis of AKI. AKI developed in 27 patients (54%) within 72 hours after transplantation. The incidence of AKI after double-lung transplantation was 87% compared to 40% following single-lung transplantation. The percentage of patients with intraoperative hypoxemia (SpO2<90%) was significantly different between the groups (AKI, 59%; Non-AKI, 22%). Volume of hydroxyethyl starch was significantly higher in AKI patients (912±507 mL) than non-AKI patients (535±338 mL). Baseline estimated glomerular filtration rate (eGFR) was significantly higher in AKI patients (99±27 mL/min/1.73 m2) than non-AKI patients (77±20 mL/min/1.73 m2). CONCLUSIONS: AKI based on the RIFLE criteria following lung transplantation is common. Patients who developed AKI were more likely to have an episode of intraoperative hypoxemia and undergo a double-lung transplantation. Contrary to other published studies, patients with a higher preoperative eGFR were more likely to develop AKI in the authors' cohort.

Persistent pneumothorax after laparoscopic appendectomy in a patient who had undergone radical esophagectomy 5 years before: possible relationship with vulnerability of the hiatus after esophagectomy: a case report.

Postoperative pneumothorax is a well-known but relatively rare complication after laparoscopic surgery. Herein, we report a case of persistent pneumothorax after laparoscopic appendectomy. A 57-year-old male, with a history of minimally invasive esophagectomy and intrathoracic gastric tube reconstruction 5 years before, underwent a laparoscopic appendectomy. A chest X-ray taken on postoperative Day 1 revealed the development of the right pneumothorax, which took more than 3 days to resolve spontaneously. Although the mechanism of postoperative pneumothorax was unclear, it seemed likely that the air that had replaced carbon dioxide in the peritoneal cavity migrated into the thoracic cavity through the esophageal hiatus, which was not covered by the peritoneum or pleura after surgical resection. The present case, together with our previous similar case, suggests that a history of esophageal cancer surgery per se increases the risk of pneumothorax after laparoscopic surgery, probably regardless of when this was performed.

Persistent bilateral pneumothorax after robotic-assisted inguinal hernia repair: possible relevance to recent esophageal cancer surgery - a case report.

BACKGROUND: Postoperative pneumothorax is a well-known but relatively rare complication after laparoscopic surgery. There has been no report describing pneumothorax that persisted for a week or more after laparoscopic surgery. Herein, we report a case of bilateral pneumothorax after laparoscopic surgery, which appears to have occurred by a different mechanism than previously described. CASE PRESENTATION: A 65-year-old male, with a past history of esophagectomy and retrosternal gastric tube reconstruction 4 months earlier, underwent a robotic-assisted inguinal hernia repair. Postoperative chest x-rays revealed the development of bilateral pneumothorax, which became worse on postoperative day (POD) 1 and took more than 9 days to resolve spontaneously. We assumed that intra-abdominal gas replaced by the air after pneumoperitoneum might have migrated into thoracic cavities through an opened esophageal hiatus or along the retrosternal route. CONCLUSIONS: Laparoscopic surgery after radical esophagectomy may be associated with an increased risk of postoperative pneumothorax.

Introduction of a Multidisciplinary Preoperative Clinic at Juntendo University Hospital - A Retrospective Observational Study Focusing on Effects of Preoperative Interventions on Clinical Outcomes.

Objectives: To investigate the effects of interventions provided by a multidisciplinary team consisting of anesthesiologists, dentists, pharmacists, and nurses at a Preoperative Clinic (POC) on postoperative outcomes. Methods: We retrospectively investigated patients who underwent preoperative evaluation at the POC at Juntendo University Hospital between May and July, 2019. Patients were divided into intervention and non-intervention groups according to whether they received intervention(s) at the POC or not. Postoperative outcomes were compared between the groups, before and after propensity score (PS) matching. Results: We investigated 909 patients who completed POC evaluation and underwent surgery. Patients in the intervention group (n = 455 [50.1%]) received at least one intervention delivered, in the order of higher delivery frequencies, by dentists, pharmacists, nurses, and anesthesiologists. Before PS matching, the intervention group was associated with older age, more frequent cardiovascular comorbidities, and higher ASA-PS grades than the non-intervention group, while neither frequencies nor severities of postoperative complications differed between the groups. These outcomes did not differ between 382 PS-matched pairs with comparable risk factors either. Conclusions: Before PS matching, postoperative outcomes did not differ between the groups, although the intervention group was associated with higher risks. These suggested that POC interventions could have improved postoperative outcomes in the higher-risk intervention group to the same level as in the non-intervention group. However, such potential beneficial effects of interventions could not be proven after PS matching. Further studies are required to elucidate effects of POC interventions on postoperative outcomes.

Acute kidney injury after lung resection surgery: incidence and perioperative risk factors.

BACKGROUND: Postoperative acute kidney injury (AKI) is associated with increased perioperative morbidity and mortality in a variety of surgical settings, but has not been well studied after lung resection surgery. In the present study, we defined the incidence of postoperative AKI, identified risk factors, and clarified the relationship between postoperative AKI and outcome in patients undergoing lung resection surgery. METHODS: A retrospective, observational study of patients who underwent lung resection surgery between January 2006 and March 2010 in a tertiary care academic center was conducted. Postoperative AKI was diagnosed within 72 hours after surgery based on the Acute Kidney Injury Network creatinine criteria. Logistic regression was used to model the association between perioperative factors and the risk of AKI within 72 hours after surgery. The relationship between postoperative AKI and patient outcome including mortality, days in hospital, and the requirement of reintubation was investigated. RESULTS: A total of 1129 patients (pneumonectomy n = 71, bilobectomy n = 30, lobectomy n = 580, segmentectomy n = 35, wedge resection/bullectomy n = 413) were included in the final analysis. Patients were an average of 61 years (SD 15) and 50% were female. AKI was diagnosed in 67 patients (5.9%) based on Acute Kidney Injury Network criteria (stage 1, n = 59; stage 2, n = 8; and stage 3, n = 0) within 72 hours after surgery, and only 1 patient required renal replacement therapy. Multivariate analysis demonstrated an independent association between postoperative AKI and hypertension (adjusted odds ratio [OR] 2.0, 95% confidence interval [CI]: 1.1-3.8), peripheral vascular disease (OR 4.4, 95% CI: 1.8-10), estimated glomerular filtration rate (OR 0.8, 95% CI: 0.69-0.93), preoperative use of angiotensin II receptor blockers (OR 2.2, 95% CI: 1.1-4.4), intraoperative hydroxyethyl starch administration (OR 1.5, 95% CI: 1.1-2.1), and thoracoscopic (versus open) procedures (OR 0.37, 95% CI: 0.15-0.90). Development of AKI was associated with increased rates of tracheal reintubation (12% vs 2%, P < 0.001), postoperative mechanical ventilation (15% vs 3%, P < 0.001), and prolonged hospital length of stay (10 vs 8 days, P < 0.001). There was no difference in mortality between the 2 groups (3% vs 1%, P = 0.12). CONCLUSIONS: Preoperative risk factors for AKI after lung resection surgery overlap with those established for other surgical procedures. Perioperative management seems to influence the risk of AKI after lung resection; in particular, the use of synthetic colloids may increase the risk, whereas thoracoscopic procedures may decrease the risk of AKI. Early postoperative AKI is associated with respiratory complications and prolonged hospitalization.

Early postoperative pulmonary complications after minimally invasive esophagectomy in the prone position: incidence and perioperative risk factors from the perspective of anesthetic management.

OBJECTIVES: To investigate the incidence of and the risk factors for early postoperative pulmonary complications (PPC) after minimally invasive esophagectomy (MIE) in the prone position from the perspective of anesthetic management. METHODS: We conducted a historical cohort study of patients who underwent MIE in the prone position between September 2010 and August 2018. PPC was defined as pneumonia, atelectasis, acute respiratory distress syndrome (ARDS), respiratory failure, and pulmonary embolism (Clavien-Dindo Classification Grade II or higher) that occurred within 7 days after MIE. RESULTS: Out of 489 patients, there were 90 patients (18.4%) with PPC: 75 patients with pneumonia, 24 patients with atelectasis, 13 patients with respiratory failure, 6 patients with ARDS, and 2 patients with pulmonary embolism. Twenty-eight patients suffered from 2 or more components of PPC. PPC patients were older (66.6 vs. 63.6 year, P = 0.038) and had higher amount of crystalloid (4200 vs. 3550 mL, P < 0.0001), and longer duration of anesthesia (670 vs. 625 min, P = 0.0062) than non-PPC patients. PPC patients were more likely to have had chronic obstructive pulmonary disease (COPD) (26.7 vs. 7.8%, P < 0.001). Incidence of PPC was significantly higher in patients with one-lung ventilation than with two-lung ventilation (37.1 vs. 15.3%, P < 0.001). Multivariable logistic regression analysis showed that PPC was associated with age (per 10 years, odds ratio (OR) = 1.41), COPD (OR = 3.43), one-lung ventilation (OR = 1.94), and volume of crystalloid (per 500 mL, OR = 1.22). CONCLUSIONS: Two-lung rather than one-lung ventilation should be chosen and fluid overload should be avoided in patients undergoing MIE in the prone position.

Disinfection of otorhinolaryngological endoscopes with electrolyzed acid water: A cross-sectional and multicenter study.

Glutaraldehyde, a germicide for reprocessing endoscopes that is important for hygiene in the clinic, might be hazardous to humans. Electrolyzed acid water (EAW) has a broad anti-microbial spectrum and safety profile and might be a glutaraldehyde alternative. We sought to assess EAW disinfection of flexible endoscopes in clinical otorhinolaryngological settings and its in vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and bacteria commonly isolated in otorhinolaryngology. Ninety endoscopes were tested for bacterial contamination before and after endoscope disinfection with EAW. The species and strains of bacteria were studied. The in vitro inactivation of bacteria and SARS-CoV-2 by EAW was investigated to determine the efficacy of endoscope disinfection. More than 20 colony-forming units of bacteria at one or more sampling sites were detected in 75/90 microbiological cultures of samples from clinically used endoscopes (83.3%). The most common genus detected was Staphylococcus followed by Cutibacterium and Corynebacterium at all sites including the ears, noses, and throats. In the in vitro study, more than 107 CFU/mL of all bacterial species examined were reduced to below the detection limit (<10 CFU/mL) within 30 s after contact with EAW. When SARS-CoV-2 was treated with a 99-fold volume of EAW, the initial viral titer (> 105 PFU) was decreased to less than 5 PFU. Effective inactivation of SARS-CoV-2 was also observed with a 19:1 ratio of EAW to the virus. EAW effectively reprocessed flexible endoscopes contributing to infection control in medical institutions in the era of the coronavirus disease 2019 pandemic.

Co-administration of ephedrine prevents reductions in cardiac output and systemic oxygen delivery secondary to lung compression maneuvers during one-lung ventilation, without reducing arterial oxygenation.

PURPOSE: We previously showed that compression of the nondependent lung during one-lung ventilation (OLV) in patients undergoing esophagectomy improves arterial oxygenation but impairs cardiac output (CO) and systemic oxygen delivery (DO(2)). The objective of this study was to test the hypothesis that the combination of nondependent lung compression and ephedrine improves arterial oxygenation without compromising DO(2). METHODS: Twenty patients undergoing esophagectomy through a right thoracotomy were studied. Under general anesthesia, a left-sided double-lumen tube was placed, and the dependent lung was mechanically ventilated with a tidal volume of 8 ml/kg and a fraction of inspiratory oxygen of 0.8 during OLV. When nondependent lung was compressed by surgeons to improve surgical exposure, a randomly determined intravenous bolus of either ephedrine 4 mg (group E) or an identical volume of saline (group S) was administered. Arterial blood was sampled during two-lung ventilation (TLV), at 10 min of OLV (OLV1), and 5 min after nondependent lung compression (OLV2). RESULTS: The initiation of OLV resulted in a significant drop in PaO(2) at OLV1 (group E, 136 ± 69 mmHg; group S, 138 ± 83 mmHg; P < 0.01) compared with TLV (group E, 404 ± 44 mmHg; group S; 367 ± 51 mmHg) and tended to improve at OLV2 (group E, 170 ± 63 mmHg; group S; 196 ± 121 mmHg). However, although CO and DO(2) significantly decreased in group S at OLV2 (4.0 ± 0.8 l/min, 621 ± 116 ml/min; P < 0.01) compared with OLV1 (5.1 ± 0.7 l/min, 811 ± 140 ml/min), there was no significant difference in these parameters in group E for the two time points. CONCLUSION: Although arterial oxygenation was not significantly improved by the nondependent lung compression, the addition of intravenous ephedrine to nondependent lung compression prevented the decrease in systemic oxygen delivery without deterioration of arterial oxygenation during OLV in patients undergoing esophagectomy.

One-lung ventilation and arterial oxygenation.

PURPOSE OF REVIEW: Hypoxemia during one-lung ventilation (OLV) has become less common; however, it may still occur in about 10% of cases. We review recent developments which may affect the incidence and treatment of hypoxemia during OLV. RECENT FINDINGS: Changes in surgical techniques are affecting oxygenation during OLV. The increased use of the supine position may adversely affect the prevalence of hypoxemia, whereas the increased application of thoracoscopic techniques is limiting the treatment options. Treatment options such as global or selective recruitment maneuvers and drug effects of dexmedetomidine and epoprostenol on arterial oxygenation during OLV are discussed. Capnometry prior to, or early during OLV, may in fact be able to predict the degree of hypoxemia during OLV. Persistent controversies surrounding the effect of epidural anesthesia, ventilatory modalities and gravity are reviewed. SUMMARY: Interesting concepts have emerged from case reports and small studies on the treatment and prediction of hypoxemia during OLV. Definitive studies on the most effective ventilatory mode remain elusive. End-organ effects of OLV are an exciting new concept that may shape clinical practice and research going forward.

Development of a voxel-matching technique for substantial reduction of subtraction artifacts in temporal subtraction images obtained from thoracic MDCT.

A temporal subtraction image, which is obtained by subtraction of a previous image from a current one, can be used for enhancing interval changes (such as formation of new lesions and changes in existing abnormalities) on medical images by removing most of the normal structures. However, subtraction artifacts are commonly included in temporal subtraction images obtained from thoracic computed tomography and thus tend to reduce its effectiveness in the detection of pulmonary nodules. In this study, we developed a new method for substantially removing the artifacts on temporal subtraction images of lungs obtained from multiple-detector computed tomography (MDCT) by using a voxel-matching technique. Our new method was examined on 20 clinical cases with MDCT images. With this technique, the voxel value in a warped (or nonwarped) previous image is replaced by a voxel value within a kernel, such as a small cube centered at a given location, which would be closest (identical or nearly equal) to the voxel value in the corresponding location in the current image. With the voxel-matching technique, the correspondence not only between the structures but also between the voxel values in the current and the previous images is determined. To evaluate the usefulness of the voxel-matching technique for removal of subtraction artifacts, the magnitude of artifacts remaining in the temporal subtraction images was examined by use of the full width at half maximum and the sum of a histogram of voxel values, which may indicate the average contrast and the total amount, respectively, of subtraction artifacts. With our new method, subtraction artifacts due to normal structures such as blood vessels were substantially removed on temporal subtraction images. This computerized method can enhance lung nodules on chest MDCT images without disturbing misregistration artifacts.

Compressing the non-dependent lung during one-lung ventilation improves arterial oxygenation, but impairs systemic oxygen delivery by decreasing cardiac output.

PURPOSE: We have previously found that compression of the non-dependent lung improves arterial oxygenation during one-lung ventilation (OLV) in patients undergoing esophagectomy. The purpose of this study was to investigate the effects of compression of the non-dependent lung on hemodynamic indices and oxygen delivery using a minimally invasive cardiac output (CO) monitor. METHODS: Sixteen consecutive patients undergoing esophagectomy through a right thoracotomy were studied. Under general anesthesia, a left-sided double-lumen tube was placed for OLV, and the dependent lung was mechanically ventilated with a tidal volume of 8 ml kg(-1) body weight and a fraction of inspiratory oxygen of 0.8 during OLV. CO was monitored continuously using a FloTrac/Vigileo (Edwards Lifesciences) system. Surgeons compressed the non-dependent lung several times during surgery using a lung retractor to improve exposure of the surgical field. The oxygen delivery index was roughly estimated as the product of the cardiac index (CI) and arterial oxygen saturation as monitored by pulse oximetry (Spo2). RESULTS: Just before non-dependent lung compression, mean (+/- SD) CI and Spo2 were 2.6 +/- 0.6 L min(-1) m(-2) and 95.0 +/- 3.9%, respectively. At 1 min after non-dependent lung compression, Spo2 increased significantly to 97.8 +/- 2.2% (P < 0.05), but CI decreased significantly to 2.0 +/- 0.4 L min(-1) m(-2) (P < 0.05). The product of CI and Spo2 at 1 min was significantly lower (192.7 +/- 37.3) than baseline levels (250.5 +/- 66.3, P < 0.05). CONCLUSION: Although non-dependent lung compression may be a potentially effective measure to treat hypoxemia during OLV, it should be noted that CO and systemic oxygen delivery may be decreased by this maneuver.

Cardiac arrest in the left lateral decubitus position and extracorporeal cardiopulmonary resuscitation during neurosurgery: a case report.

Cardiopulmonary resuscitation (CPR) in the lateral position during noncardiac surgery has been described in only a few reports in the past. Here, we report a case of cardiac arrest in a 61-year-old man undergoing microvascular decompression surgery for trigeminal neuralgia in the left lateral decubitus position. During the initial 5 min of CPR, chest compression was performed in this position by two rescuers; one from the chest and the other from the back, pushing simultaneously. Because ventricular arrhythmia was refractory to conventional CPR even after placing the patient back to the supine position, extracorporeal life support was introduced in the operating room by using the femoro-femoral approach (right atrio-femoral veno-arterial bypass). This alternative CPR markedly decreased the frequency of ventricular arrhythmia. Subsequent coronary angiogram detected 99% stenosis of the right coronary artery. Ventricular arrhythmia ceased after coronary revascularization, and the patient was successfully weaned from the extracorporeal bypass circuit. The patient was discharged alive with minimal neurological impairment. We suggest that chest compression in the lateral position by two rescuers is an efficient resuscitation maneuver, and if an electrical storm is refractory to conventional CPR, extracorporeal life support should be considered in the operating-room setting.

[A DRG/PPS simulation in the medical care of tuberculosis].

PURPOSE: To study the expected usefulness of the introduction of the DRG-PPS (Diagnosis-Related Group/Prospective Payment System, in which an insurer pays a fixed medical fee per hospitalization) into the current medical care of tuberculosis (TB) in Japan. METHOD: The medical fees were reviewed for all TB inpatients at 19 hospitals under the National Hospital Organization who were discharged in either June 2007 or February 2008. The sum of the fixed fee by the DRG was assumed based on the bivariate regression analysis of each patient's hospital days and his or her total actual fees during the hospital stay under the current (fee for care) system, since it was difficult to directly calculate the daily fees for every patient that would be the basis of DRG-PPS. RESULTS: Linear regression analysis estimated that the medical fees (including fees for the medical examinations and the treatments) for a hospital stay of 60 days, which is the standard for TB treatment, was 1,192,470 yen (19,870 yen per person per day) in June 2007, and 1,167,600 yen (19,460 yen per person per day) in February 2008. DISCUSSION: If we assume an average medical fee of about Y1.1-1.2 million yen for the standard hospital care of TB, the economic balance of the hospitals is negative, with a deficit of 0.6-0.7 million yen, given the estimated expenses of 1.8 million yen (i.e., 30,000 yen per person per day x 60 days). CONCLUSION: If the DRG-PPS is to be implemented based on the current medical fee rating system, the hospital administrators could not accept its introduction to the TB medical care service as it is, because it may undermine the economic management of hospitals.