Correction to: Protective ventilation with high versus low positive end-expiratory pressure during one-lung ventilation for thoracic surgery (PROTHOR): study protocol for a randomized controlled trial.

After publication of the original article [1], the authors have notified us that two of the collaborator first and last names have been inverted in the "PROTHOR Investigators" table.

Protective ventilation with high versus low positive end-expiratory pressure during one-lung ventilation for thoracic surgery (PROTHOR): study protocol for a randomized controlled trial.

BACKGROUND: Postoperative pulmonary complications (PPC) may result in longer duration of in-hospital stay and even mortality. Both thoracic surgery and intraoperative mechanical ventilation settings add considerably to the risk of PPC. It is unclear if one-lung ventilation (OLV) for thoracic surgery with a strategy of intraoperative high positive end-expiratory pressure (PEEP) and recruitment maneuvers (RM) reduces PPC, compared to low PEEP without RM. METHODS: PROTHOR is an international, multicenter, randomized, controlled, assessor-blinded, two-arm trial initiated by investigators of the PROtective VEntilation NETwork. In total, 2378 patients will be randomly assigned to one of two different intraoperative mechanical ventilation strategies. Investigators screen patients aged 18 years or older, scheduled for open thoracic or video-assisted thoracoscopic surgery under general anesthesia requiring OLV, with a maximal body mass index of 35 kg/m2, and a planned duration of surgery of more than 60 min. Further, the expected duration of OLV shall be longer than two-lung ventilation, and lung separation is planned with a double lumen tube. Patients will be randomly assigned to PEEP of 10 cmH2O with lung RM, or PEEP of 5 cmH2O without RM. During two-lung ventilation tidal volume is set at 7 mL/kg predicted body weight and, during OLV, it will be decreased to 5 mL/kg. The occurrence of PPC will be recorded as a collapsed composite of single adverse pulmonary events and represents the primary endpoint. DISCUSSION: PROTHOR is the first randomized controlled trial in patients undergoing thoracic surgery with OLV that is adequately powered to compare the effects of intraoperative high PEEP with RM versus low PEEP without RM on PPC. The results of the PROTHOR trial will support anesthesiologists in their decision to set intraoperative PEEP during protective ventilation for OLV in thoracic surgery. TRIAL REGISTRATION: The trial was registered in clinicaltrials.gov ( NCT02963025 ) on 15 November 2016.

One-lung ventilation does not result in cerebral desaturation during application of lung protective strategy if normocapnia is maintained.

BACKGROUND: Previously a report has suggested that administration of lung protective strategy for one-lung ventilation(OLV) results in oxygen desaturation of the brain parenchyma. The aim of our work was to confirm that the maintenance of normocapnia during protective OLV strategy results in alteration of cerebral blood fl ow and cerebral oxygen saturation as compared to double-lung ventilation. METHODS: Data were obtained from 24 patients undergoing thoracic surgery. Cerebral oxygen saturation (rSO2) was continuously monitored by INVOS 5100C Cerebral Oxymeter System along with measurement of cerebral blood fl ow velocity (MCAV) by transcranial Doppler sonography. Arterial blood samples were taken for blood gas analysis in the awake state, in the supine and lateral decubitus position during double-lung ventilation (DLV), and during OLV. RESULTS: When ventilation was changed from DLV to OLV, no significant change was observed in rSO2. A significant decrease of rSO2 was found compared to the value observed during DLV in lateral decubitus at the time point 60 minutes after the start of OLV. No clinically significant changes in the MCAV was observed throughout the course of the thoracic surgical procedure. CONCLUSIONS: OLV does not result in clinically relevant decreases in cerebral blood fl ow and cerebral oxygen saturation during application of lung protective ventilation if normocapnia is maintained.

Effects of different tidal volumes for one-lung ventilation on oxygenation with open chest condition and surgical manipulation: a randomised cross-over trial.

BACKGROUND: The ideal tidal volume (TV) during one-lung ventilation (OLV) remains controversial. High TVs may increase the incidence of postoperative lung injury after thoracic surgery. There is nonetheless little evidence that the use of low TV during OLV will fail to provide adequate arterial oxygenation. We evaluated the influence of low (5 mL/kg-1) and high (10 mL/kg-1) TV on arterial oxygenation during one-lung ventilation in clinical conditions. METHODS: A hundred patients scheduled for lung surgery were studied. Patients were randomly assigned to either 30 minutes of one-lung ventilation with a TV of 10 mL/kg-1 at a rate of 10 breaths/minute (Group 10, N.=50) or a TV of 5 mL/kg-1 with 5 cmH2O PEEP at a rate of 20 breaths/minute (Group 5, N.=50). According to the rules of crossover design during the subsequent 30 minutes, each patient received the alternative management. Arterial blood partial pressures, hemodynamic responses, and ventilatory parameters were recorded. Results are presented as means ± SDs; P<0.05 was considered statistically significant. RESULTS: PaO2 was unaffected by TV (10 mL/kg-1: 218±106 versus 5 mL/kg-1: 211±119 mmHg, P=0.29). Calculated intrapulmonary shunt fraction was also similar with each TV during OLV (5 mL/kg-1: 25±9% versus 10 mL/kg-1: 24±8%, p=0.14). In contrast, low TV significantly increased PaCO2 (10 mL/kg-1: 39±6 versus 5 mL/kg-1: 44±8 mmHg, P<0.001). There were significant differences both in peak (10 mL/kg-1: 27±6 versus 5 mL/kg-1: 21±5 cmH2O, P<0.001) and plateau airway pressure values (10 mL/kg-1: 22±6 versus 5 mL/kg-1: 18±5 cmH2O, P<0.001) during OLV. CONCLUSION: Low TV (5 mL/kg-1) accompanied by 5 cmH2O PEEP provides comparable arterial oxygenation and intrapulmonary shunt fraction during one-lung ventilation as higher TV (10 mL/kg-1) without PEEP.

Haemostasis monitoring during sequential aortic valve replacement and liver transplantation.

Despite advances in anaesthesiological and surgical techniques, cardiac surgery in cirrhotic patients remains hazardous. This report outlines our experience with haemostasis monitoring in two consecutive cases of sequential aortic valve replacement and liver transplantation. Clotting disturbances proved to have fatal consequences since one of these patients died following massive lung embolism. The second patient underwent successfully this combined procedure and is in good clinical state 14 months postoperatively. Evaluation and discussion of the coagulation monitoring by the Sonoclot Analyzer in both patients and related therapeutic suggestions for the prevention of thrombotic events are discussed.

Gravity is an important determinant of oxygenation during one-lung ventilation.

BACKGROUND: The role of gravity in the redistribution of pulmonary blood flow during one-lung ventilation (OLV) has been questioned recently. To address this controversial but clinically important issue, we used an experimental approach that allowed us to differentiate the effects of gravity from the effects of hypoxic pulmonary vasoconstriction (HPV) on arterial oxygenation during OLV in patients scheduled for thoracic surgery. METHODS: Forty patients with chronic obstructive pulmonary disease scheduled for right lung tumour resection were randomized to undergo dependent (left) one-lung ventilation (D-OLV; n=20) or non-dependent (right) one-lung ventilation (ND-OLV; n=20) in the supine and left lateral positions. Partial pressure of arterial oxygen (PaO2) was measured as a surrogate for ventilation/perfusion matching. Patients were studied before surgery under closed chest conditions. RESULTS: When compared with bilateral lung ventilation, both D-OLV and ND-OLV caused a significant and equal decrease in PaO(2) in the supine position. However, D-OLV in the lateral position was associated with a higher PaO2 as compared with the supine position [274.2 (77.6) vs. 181.9 (68.3) mmHg, P<0.01, analysis of variance (ANOVA)]. In contrast, in patients undergoing ND-OLV, PaO2 was always lower in the lateral as compared with the supine position [105.3 (63.2) vs. 187 (63.1) mmHg, P<0.01, ANOVA]. CONCLUSION: The relative position of the ventilated vs. the non-ventilated lung markedly affects arterial oxygenation during OLV. These data suggest that gravity affects ventilation-perfusion matching independent of HPV.

Comparison of volume-controlled and pressure-controlled ventilation during laparoscopic gastric banding in morbidly obese patients.

BACKGROUND: There are no guidelines on ventilation modes in morbidly obese patients. We investigated the effects of volume-controlled (VCV) and pressure-controlled ventilation (PCV) on gas exchange, respiratory mechanics, and cardiovascular responses in laparoscopic gastric banding procedures. METHODS: After Institutional Review Board approval, 24 adult consenting patients scheduled for laparoscopic gastric banding were studied. Anesthesia was standardized using remifentanil, propofol, rocuronium, and sevoflurane. All patients started with VCV with a tidal volume of 10 ml kg(-1) ideal body weight, respiratory rate adjusted to obtain an end-tidal carbon dioxide of 35-40 mmHg, positive end-expiratory pressure of 5 cmH2O, an inspiratory pause of 10% and an inspiratory/expiratory ratio of 1:2. Fifteen minutes after pneumoperitoneum, the patients were randomly allocated to two groups. In Group VCV (n = 12), ventilation was with the same parameters. In Group PCV (n = 12), the airway pressure was set to provide a tidal volume of 10 ml kg(-1) ideal body weight without exceeding 35 cm H2O. Respiratory rate was adjusted to keep an end-tidal carbon dioxide of 35-40 mmHg. Arterial blood samples were drawn after surgical positioning and 15 min after allocation. Analysis of variance (ANOVA) was used for statistical analysis. RESULTS: With constant minute ventilation, VCV generates equal airway pressures and cardiovascular effects with a lower PaCO2 as compared to PCV (42.5 (5.2) mmHg versus 48.9 (4.3) mmHg, p < 0.01 ANOVA). Arterial oxygenation remained unchanged. CONCLUSIONS: VCV and PCV appear to be an equally suited ventilatory technique for laparoscopic procedures in morbidly obese patients. Carbon dioxide elimination is more efficient when using VCV.

Augmented serum lactic acid combined with metabolic alkalosis: a case report.

Lactic acidosis is a common problem in the peri-operative period. During extensive surgery we frequently have an augmentation of lactic acid most often on the basis of hypoperfusion. Normally, a rise in serum lactate level causes a fall in blood pH, and this metabolic acidosis is accompanied by a high anion gap. In this case report a perioperative rise in lactic acid and an elevation in serum pH in a patient during meningeal tumour surgery is presented.

Peri-operative spirometry: tool or gadget?

More and more anesthesia machines are foreseen with spirometry monitoring. Nevertheless, the use of such equipment needs some interpretation skills for the displayed curves and numerical values otherwise it remains just a disturbing gadget rather than a powerful tool. This review explains in his first part the basic principles of interpretation of the spirometric data, and in the second part gives concrete examples of clinical situations.

Anaesthesia for a patient with Leigh's syndrome undergoing surgery for scoliosis.

Anaesthesia for patients with Leigh's syndrome has rarely been reported. Leigh's syndrome or subacute necrotizing encephalomyelopathy is a neurodegenerative disorder of infancy or childhood. Acute exacerbation with respiratory failure may accompany surgery and general anaesthesia. In this case report we describe the anaesthetic management of a 17 year old patient scheduled for spine surgery.

Intrinsic positive end-expiratory pressure during one-lung ventilation of patients with pulmonary hyperinflation. Influence of low respiratory rate with unchanged minute volume.

BACKGROUND: We measured lung mechanics and gas exchange during one-lung ventilation (OLV) of patients with chronic obstructive pulmonary disease, using three respiratory rates (RR) and unchanged minute volume. METHODS: We studied 15 patients about to undergo lung surgery, during anaesthesia, and placed in the lateral position. Ventilation was with constant minute volume, inspiratory flow and FIO2. For periods of 15 min, RR of 5, 10, and 15 bpm were applied in a random sequence and recordings were made of lung mechanics and an arterial blood gas sample was taken. Data were analysed with the repeated measures ANOVA and paired t-test with Bonferroni correction. RESULTS: PaO2 changes were not significant. At the lowest RR, PaCO2 decreased (from 42 (SD 4) mm Hg at RR 15-41 (4) mm Hg at RR 10 and 39 (4) mm Hg at RR 5, P<0.01), and end-tidal carbon dioxide increased (from 33 (5) mm Hg at RR 15 to 35 (5) mm Hg at RR 10 and 36 (6) mm Hg at RR 5, P<0.01). Intrinsic positive end-expiratory pressure (PEEPi) was reduced even with larger tidal volumes (from 6 (4) cm H2O at RR 15-5 (4) cm H2O at RR 10, and 3 (3) cm H2O at RR 5, P<0.01), most probably caused by increased expiratory time at the lowest RR. CONCLUSION: A reduction in RR reduces PEEPi and hypercapnia during OLV in anaesthetized patients with chronic obstructive lung disease.

Pathophysiology of one-lung ventilation.

The management of some problematic patients having thoracic surgery is among the most difficult challenges for the anesthesiologist. Increasingly complex operations are performed on seriously compromised patients because of the development of new surgical techniques and the anesthesiologists' awareness of surgical needs and requirements to provide a satisfactory and safe surgical field. In order to facilitate thoracic surgery, the single most important and valuable anesthetic technique used actually is one-lung ventilation. This article reviews the complex pathopysiology of one-lung ventilation.

Two-lung and one-lung ventilation in patients with chronic obstructive pulmonary disease: the effects of position and F(IO)2.

UNLABELLED: We compared the effects of position and fraction of inspired oxygen (F(IO)2) on oxygenation during thoracic surgery in 24 consenting patients randomly assigned to receive an F(IO)2 of 0.4 (eight patients, Group 0.4), 0.6 (eight patients, Group 0.6), or 1.0 (eight patients, Group 1.0) during the periods of two-lung (TLV) and one-lung ventilation (OLV) in the supine and lateral positions. TLV and OLV were maintained while the patients were first in the supine and then in the lateral position for 15 min each. Thereafter, respiratory mechanical data were obtained, and arterial blood gas samples were drawn. Pao2 decreased during OLV compared with TLV in both the supine and lateral positions. In all three groups, Pao2 was significantly higher during OLV in the lateral than in the supine position: 101 (72-201) vs 63 (57-144) mm Hg in Group 0.4; 268 (162-311) vs 155 (114-235) mm Hg in Group 0.6; and 486 (288-563) vs 301 (216-422) mm Hg in Group 1.0, respectively (P < 0.02, Wilcoxon's signed rank test). We conclude that, compared with the supine position, gravity augments the redistribution of perfusion as a result of hypoxic pulmonary vasoconstriction, when patients are in the lateral position, which explains the higher Pao2 during OLV. IMPLICATIONS: This study compares oxygenation during thoracic surgery during periods of two-lung and one-lung ventilation with patients in the supine and lateral positions when using three different fraction of inspired oxygen values. Arterial oxygen tension was decreased in all three groups during one-lung ventilation in comparison with the two-lung ventilation values, but the decrease was significantly less in the lateral, compared with the supine position.

Airway pressure changes during one-lung ventilation.

This investigation analyzed the changes in inspiratory airway pressures during transition from two-lung to one-lung ventilation in patients tracheally intubated with a double-lumen endotracheal tube (DLT) using a classical method of intubation without fiberoptic bronchoscopy. All patients were anesthetized in a standardized fashion. Ventilation was accomplished with the Siemens 900 constant-flow mechanical ventilator (Solna, Sweden). Peak (Ppeak) and plateau (Pplateau) inspiratory airway pressures were recorded with an on-line respiratory monitor before and after clamping the tracheal limb of the DLT. The position of the DLTs was evaluated by fiberoptic bronchoscopy with the patient in supine position. Of the 51 intubations, the DLT was malpositioned in 15 cases (29.5%). Ppeak and Pplateau increased significantly when switched from two-lung ventilation to one-lung ventilation in both correctly and incorrectly positioned DLTs. When the DLT was in a correct position, Ppeak increased by a mean of 55.1% and Pplateau increased by a mean of 41.9%. When the DLT was malpositioned, this increase was significantly larger (74.9% and 68.8%, respectively). Three tests commonly used as markers of malpositioned DLTs were evaluated based on the data of this study, and it was established that, although the pressure differences related to position are statistically significant, as a single value, they cannot be used for clinical decision making.

New findings concerning the pathogenesis of acute carbon monoxide (CO) poisoning.

The pathomechanism of carbon monoxide (CO) poisoning was studied by means of cardiopathological and neuropathological investigations in experimental CO intoxication. It has been shown that besides CO-hemoglobin association, the binding of CO to cytochromes is a significant factor. The latter is thought to be responsible for the cytotoxic phenomena. Combined ultrastructural and cytochemical studies have enabled differentiation between toxic, hypoxic, and mixed alternations.