Helmut Hager

Randomized clinical trial comparing double-lumen tube and EZ-Blocker® for single-lung ventilation

BACKGROUND In several clinical situations, lung separation and single-lung ventilation (SLV) is essential. In these cases, the double-lumen tube (DLT) is the most widely used device. Bronchial blocker such as Univent or Arndt Blocker serves as an alternative. The EZ-Blocker(®) (EZ; AnaesthetIQ B.V., Rotterdam, The Netherlands) is a new device promising to exceed clinical performance of DLT. The aim of this study was to assess the clinical performance of EZ in comparison with conventional left-sided DLT. METHODS Forty adult patients undergoing elective thoracic surgery requiring thoracotomy and SLV were included in this study. The patients were randomly assigned to one of two groups: EZ (combined with conventional 7.5 or 8.5 mm single-lumen tube) or DLT (37 or 39 Fr left-sided DLT). Time for intubation procedure and time to verification of the correct position of EZ or DLT using fibreoptic bronchoscopy (FOB) were recorded. After surgery, a thoracic surgeon rated the quality of collapse of the lung (1-3 on a three-level scale). RESULTS Time for intubation using DLT 85.5 (54.8) s was significantly faster (P<0.001) than using EZ 192 (89.7) s, whereas time for bronchoscopy was not significantly different (P=0.556). Conditions of surgery were rated equally [DLT 1.3 (0.6) vs EZ 1.4 (0.6), P=0.681]. CONCLUSIONS Although time for intubation was longer with the EZ, the device proved to be an efficient and easy-to-use device. The EZ is a valuable alternative device to conventional DLT. Verification of the correct position of the EZ by FOB seems to be obligatory. This study was registered at http://www.clinicaltrials.gov (identifier: NCT01171560).

Extended videoscopic robotic thymectomy with the da Vinci telemanipulator for the treatment of myasthenia gravis: the Vienna experience.

Surgical treatment of myasthenia gravis should include the complete resection of the thymus with the whole fatty tissue adherent to the pericardium for immunologic as well as oncologic reasons. The aim of the current study was to investigate the efficacy and safety of robotic approach. A total of 18 patients with myasthenia gravis (mean age 44 years) have been operated robotically via a left-sided approach. Preoperative MGFA (Myasthenia Gravis Foundation of America) classification was: Class I n=4, Class IIa n=4, Class IIb n=5, and Class IIIa n=3, IIIb n=2. Total endoscopic resection was feasible in 17/18 patients. One patient had to be converted due to bleeding. In the remaining patients, operative time was 175 min, intensive care unit (ICU) one day, hospital stay four days. In all patients it was possible to perform an extended thymic resection. MGFA post-intervention status after a mean of 18 months follow-up showed complete stable remission n=5, pharmacologic remission n=4, minimal manifestations n=5, unchanged n=1. Complete endoscopic thymus surgery with the da Vinci surgical system enables a complete and extended resection of all thymic tissue in the mediastinum. Due to the minimal trauma, patients can return to full activity within a short time.

Standard donor lung procurement with normothermic ex vivo lung perfusion: A prospective randomized clinical trial

BACKGROUND Ex vivo lung perfusion (EVLP) was primarily developed for evaluation of impaired donor lungs. The good clinical results raise the question for its possible impact on lungs meeting standard criteria. Before application of EVLP on such lungs enters routine clinical practice, it must be demonstrated whether EVLP would affect or improve outcome when used in standard donor lungs. We performed a prospective randomized trial to investigate the role of EVLP in standard lung transplantation (Tx). METHODS This prospective randomized clinical trial compared patients who underwent Tx with ex vivo evaluated donor lungs with an equivalent patient population without previous EVLP. RESULTS From October 2013 to May 2015, 193 lung Tx were performed at the Medical University of Vienna. During this period, 80 recipient/donor pairs that met the inclusion criteria were included in this trial, 41 pairs in the control group, and 39 in the EVLP group. In the EVLP group, 4 lungs (10.2%) ultimately did not qualify for Tx and were rejected for lung Tx owing to technical reasons (n = 2) and quality criteria (n = 2). Donor and recipient characteristics were comparable in both groups. Total cold ischemic time in the EVLP group was significantly longer for both implanted lungs (first side, 372 minutes vs 291 minutes, p < 0.001; second side, 437 minutes vs 370 minutes, p = 0.001); median duration of surgery showed no differences (277 minutes vs 275 minutes). Median oxygen partial pressure/fraction of inspired oxygen ratio at 24 hours after Tx was 516 (range, 280-557) in the EVLP group and 491 (range, 352-575) in the control group (p = 0.63). Incidence of primary graft dysfunction >1 was lower in the EVLP group at all time points compared with the control group (24 hours, 5.7% vs 19.5%, p = 0.10), and need for post-operative prolonged extracorporeal membrane oxygenation was lower in the EVLP group (5.7% vs 12.2%, p = 0.44). Short-term clinical outcomes did not differ between recipients in the 2 groups. Patients remained intubated (1.6 days vs 1.6 days, p = 0.67), in the intensive care unit (6 days vs 6 days, p = 0.76), and in the hospital (23 days vs 19 days, p = 0.42) for a comparable period of time. The 30-day survival was 97.1% vs 100% (p = 0.46). CONCLUSIONS This study provides evidence that EVLP can safely be used in standard donor lungs. Functional results and perioperative outcome are comparable to those achieved with standard donor lung preservation techniques. As an evaluation tool, EVLP allows clinicians to identify and to possibly exclude lungs with functional impairment. Finally, EVLP can safely extend total preservation time.

Assessing intravascular volume by difference in pulse pressure in pigs submitted to graded hemorrhage.

ABSTRACT We assessed changes in intravascular volume monitored by difference in pulse pressure (dPP%) after stepwise hemorrhage in an experimental pig model. Six pigs (23-25 kg) were anesthetized (isoflurane 1.5 vol%) and mechanically ventilated to keep end-tidal CO2 (etCO2) at 35 mmHg. A PA-catheter and an arterial catheter were placed via femoral access. During and after surgery, animals received lactated Ringers solution as long as they were considered volume responders (dPP > 13%). Then animals were allowed to stabilize from the induction of anesthesia and insertion of catheters for 30 min. After stabilization, baseline measurements were taken. Five percent of blood volume was withdrawn, followed by another 5%, and then in 10%-increments until death from exsanguination occurred. After withdrawal of 5% of blood volume, all pigs were considered volume responders (dPP > 13%); dPP rose significantly from 6.1 ± 3.3% to 19.4 ± 4.2%. The regression analysis of stepwise hemorrhage revealed a linear relation between blood loss (hemorrhage in %) and dPP (y = 0.99* × + 14; R2 = 0.7764; P < .0001). In addition, dPP was the only parameter that changed significantly between baseline and a blood loss of 5% (P < 0.01), whereas cardiac output, stroke volume, heart rate, MAP, central venous pressure, pulmonary artery occlusion pressure, and systemic vascular resistance, respectively, remained unchanged. We conclude that in an experimental hypovolemic pig model, dPP correlates well with blood loss.

Performance of supraglottic airway devices and 12 month skill retention: A randomized controlled study with manikins

PURPOSE Airway management for successful ventilation by laypersons and inexperienced healthcare providers is difficult to achieve. Bag-valve mask (BVM) ventilation requires extensive training and is performed poorly. Supraglottic airway devices (SADs) have been successfully introduced to clinical resuscitation practice as an alternative. We evaluated recently introduced (i-gel™ and LMA-Supreme™) and established SADs (LMA-Unique™, LMA-ProSeal™) and BVM used by laypeople in training sessions on manikins. METHODS In this randomized controlled study, 267 third-year medical students participated with informed consent and IRB approval. After brief standardized training, each participant applied all devices in a randomized order. Success of device application and ventilation was recorded. Without further training, skill retention was assessed in the same manner 12 months later. Outcome parameters were the number of application attempts, application time, tidal volume and gastric inflation rate recorded at successful attempts, and subjective ease-of-use rating by the participants. RESULTS i-gel™ and LMA-Supreme™ were the most successful in the first attempt at both assessments and in the subjective ease-of-use rating. The shortest application time was found with BVM (8 ± 5s in 2008 vs. 9 ± 5s in 2009) and i-gel (10 ± 3s vs. 12 ± 5s). Tidal volumes were disappointing with no device reaching 50% volume within the recommended range (0.4-0.6L). Gastric inflation rate was highest with BVM (18% vs. 20%) but significantly lower with all SADs (0.4-6%; p < 0.001 for 2008 and 2009). CONCLUSION SADs showed clear advantages over BVM. Compared with LMA-Unique™ and LMA-ProSeal™, i-gel™ and LMA-Supreme™ led to higher first-attempt success rates and a shorter application time.

Hemodynamic parameters change earlier than tissue oxygen tension in hemorrhage

BACKGROUND Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. MATERIALS AND METHODS Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after preparation, baseline measurements were taken. At first, 5% of total blood volume was withdrawn, followed by another 5% increment, and then in 10% increments until death. RESULTS After withdrawal of 5% of estimated blood volume, dPP increased from 6.1% +/- 3.0% to 20.8% +/- 2.7% (P < 0.01). Mean arterial pressure (MAP), mean pulmonary artery pressure (PAP) and pulmonary artery occlusion pressure (PAOP) decreased with a blood loss of 10% (P < 0.01). Cardiac output (CO) changed after a blood loss of 20% (P < 0.05). Tissue oxygen tension in central organs, and blood flow in the jejunal muscularis decreased (P < 0.05) after a blood loss of 20%. Tissue oxygen tension in the skin, and jejunal mucosa blood flow decreased (P < 0.05) after a blood loss of 40% and 50%, respectively. CONCLUSIONS In this hemorrhagic pig model systemic hemodynamic parameters were more sensitive to detect acute hypovolemia than tissue oxygen tension measurements or jejunal LDF measurements. Acute blood loss was detected first by dPP.

The influence of stellate ganglion transcutaneous electrical nerve stimulation on signal quality of pulse oximetry in prehospital trauma care

BACKGROUND: Accurate monitoring of the peripheral arterial oxygen saturation has become an important tool in the prehospital emergency medicine. This monitoring requires an adequate plethysmographic pulsation. Signal quality is diminished by cold ambient temperature due to vasoconstriction. Blockade of the stellate ganglion can improve peripheral vascular perfusion and can be achieved by direct injection or transcutaneous electrical nerve stimulation (TENS) stimulation. We evaluated whether TENS on the stellate ganglion would reduce vasoconstriction and thereby improve signal detection quality of peripheral pulse oximetry. METHODS: In our study, 53 patients with minor trauma who required transport to the hospital were enrolled. We recorded vital signs, including core and skin temperature before and after transport to the hospital. Pulse oximetry sensors were attached to the patient’s second finger on both hands. TENS of the stellate ganglion was started on one side after the beginning of the transport. Pulse oximeter alerts, due to poor signal detection, were recorded for each side separately. RESULTS: On the hand treated with TENS we detected a significant reduction of alerts compared to the other side (mean alerts TENS 3.1 [1–15] versus control side 8.8 [1–28] P < 0.05). The duration of dropouts was shorter as well (mean duration TENS 77 [16–239] s versus control side 333 [78–1002] s). CONCLUSION: The data indicate that blockade of the stellate ganglion with TENS improves signal quality of pulse oximeters in the prehospital setting.

Intraoperative extracorporeal membrane oxygenation and the possibility of postoperative prolongation improve survival in bilateral lung transplantation

Objectives: The value of intraoperative extracorporeal membrane oxygenation (ECMO) in lung transplantation remains controversial. In our department, ECMO has been used routinely for intraoperatively unstable patients for more than 15 years. Recently, we have extended its indication to a preemptive application in almost all cases. In addition, we prolong ECMO into the early postoperative period whenever graft function does not meet certain quality criteria or in patients with primary pulmonary hypertension. The objective of this study was to review the results of this strategy. Methods: All standard bilateral lung transplantations performed between January 2010 and June 2016 were included in this single‐center, retrospective analysis. Patients were divided into 3 groups: group I—no ECMO (n = 116), group II—intraoperative ECMO (n = 343), and group III—intraoperative and prolonged postoperative ECMO (n = 123). The impact of different ECMO strategies on primary graft function, short‐term outcomes, and patient survival were analyzed. Results: The use of intraoperative ECMO was associated with improved 1‐, 3‐, and 5‐year survival compared with non‐ECMO patients (91% vs 82%, 85% vs 76%, and 80% vs 74%; log‐rank P = .041). This effect was still evident after propensity score matching of both cohorts. Despite the high number of complex patients in group III, outcome was excellent with higher survival rates than in the non‐ECMO group at all time points. Conclusions: Intraoperative ECMO results in superior survival when compared with transplantation without any extracorporeal support. The concept of prophylactic postoperative ECMO prolongation is associated with excellent outcomes in recipients with pulmonary hypertension and in patients with questionable graft function at the end of implantation.

Effects of high-urgency ambulance transportation on pro-B-type natriuretic peptide levels in patients with heart failure.

OBJECTIVES We hypothesized that pro-B-type natriuretic peptide (proBNP) levels in venous blood increase in patients with acute out-of-hospital heart failure because of stress during emergency ambulance transportation, and furthermore, we wanted to show if there is an effect of increasing proBNP levels on hemodynamic parameters. METHODS Venous proBNP levels, visual analog scale (VAS) for pain and anxiety before and after transportation, heart rate, blood pressure, and transcutaneous Spo(2) were measured every 3 minutes in 32 patients with defined clinical signs of heart failure. RESULTS ProBNP levels increased significantly (P < .01) during transportation (278.13 +/- 113.20 vs 984.67 +/- 627.33 pg/mL), whereas heart rate and mean blood pressure remained almost stable. There was no significant change in VAS for pain and anxiety (3.79 +/- 3.70 and 2.89 +/- 3.01 vs 2.13 +/- 3.30 and 1.57 +/- 2.78). CONCLUSION A rapid increase in proBNP levels was shown in patients with acute out-of-hospital heart failure during emergency ambulance transportation but no significant changes in hemodynamic parameters.

Lung transplantation for idiopathic pulmonary arterial hypertension on intraoperative and postoperatively prolonged extracorporeal membrane oxygenation provides optimally controlled reperfusion and excellent outcome

Abstract OBJECTIVES Lung transplantation for idiopathic pulmonary arterial hypertension has the highest reported postoperative mortality of all indications. Reasons lie in the complexity of treatment of these patients and the frequent occurrence of postoperative left ventricular failure. Transplantation on intraoperative extracorporeal membrane oxygenation support instead of cardiopulmonary bypass and even more the prolongation of extracorporeal membrane oxygenation into the postoperative period helps to overcome these problems. We reviewed our experience with this concept. METHODS All patients undergoing bilateral lung transplantation for idiopathic pulmonary arterial hypertension on intraoperative extracorporeal membrane oxygenation with or without prophylactic extracorporeal membrane oxygenation prolongation into the postoperative period between January 2000 and December 2014 were retrospectively analysed. RESULTS Forty-one patients entered the study. Venoarterial extracorporeal membrane oxygenation support was prolonged into the postoperative period for a median of 2.5 days (range 1–40). Ninety-day, 1-, 3- and 5-year survival rates for the patient collective were 92.7%, 90.2%, 87.4% and 87.4%, respectively. When compared with 31 patients with idiopathic pulmonary arterial hypertension transplanted in the same period of time without prolongation of extracorporeal membrane oxygenation into the postoperative period, the results compared favourably (83.9%, 77.4%, 77.4%, and 77.4%; P = 0.189). Furthermore, these results are among the best results ever reported for this particularly difficult patient population. CONCLUSIONS Bilateral lung transplantation for idiopathic pulmonary arterial hypertension with intraoperative venoarterial extracorporeal membrane oxygenation support seems to provide superior outcome compared with the results reported about the use of cardiopulmonary bypass. Prophylactic prolongation of venoarterial extracorporeal membrane oxygenation into the early postoperative period provides stable postoperative conditions and seems to further improve the results.