Dirk Buchwald

Beating-Heart Coronary Artery Bypass Grafting With Miniaturized Cardiopulmonary Bypass Results in a More Complete Revascularization When Compared to Off-Pump Grafting

The technique of miniaturized cardiopulmonary bypass (M-CPB) for beating-heart coronary artery bypass grafting (CABG) is relatively new and has potential advantages when compared to conventional cardiopulmonary bypass (CPB). M-CPB consists of less tubing length and requires less priming volume. The system is phosphorylcholine coated and results in minimal pump-related inflammatory response and organ injury. Finally, this technique combines the advantages of the off-pump CABG (OPCAB) with the better exposure provided by CPB to facilitate complete revascularization. The hypothesis is that CABG with M-CPB has a better outcome in terms of complete coronary revascularization and perioperative results as that compared to off-pump CABG (OPCAB). In a retrospective study, 302 patients underwent beating-heart CABG, 117 (39%) of them with the use of M-CPB and 185 (61%) with OPCAB. After propensity score matching 62 patients in both groups were demographically similar. The most important intra- and early-postoperative parameters were analyzed. Endpoints were hospital mortality and complete revascularization. Hospital mortality was comparable between the groups. The revascularization was significantly more complete in M-CPB patients than in patients in the OPCAB group. Beating-heart CABG with M-CPB is a safe procedure and it provides an optimal operative exposure with significantly more complete coronary revascularization when compared to OPCAB. Beating-heart CABG with the support of a M-CPB is the operation of choice when total coronary revascularization is needed.

Veno-venous extracorporeal membrane oxygenation in obese surgical patients with hypercapnic lung failure.

In patients with a body mass index (BMI) > 35 kg/m2, or in extreme cases weighting > 250 kg, we are faced with special challenges in therapy and logistics. The aim was to analyze the feasibility of the extracorporeal membrane oxygenation (ECMO) in these patients.

Use of extracorporeal membrane oxygenation in combination with high-frequency oscillatory ventilation in post-traumatic ARDS.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life‐threatening complications in trauma patients. Despite the implantation of a veno‐venous extracorporeal membrane oxygenation (vv ECMO), sufficient oxygenation (arterial SaO2 > 90%) is not always achieved. The additive use of high‐frequency oscillation ventilation (HFOV) and ECMO in the critical phase after trauma could prevent the occurrence of life‐threatening hypoxaemia and multi‐organ failure.

[Off-pump versus on-pump coronary artery bypass surgery. Comparison of 270 case-matched elderly patients].

Ob sich durch die „Off Pump Coronary Artery Bypass“ – Chirurgie die perioperative Morbidität und Mortalität senken lässt, ist noch immer eine kontrovers geführte Diskussion. Die vorliegende Studie vergleicht die Ergebnisse von älteren Patienten, die mit bzw. ohne Herz–Lungen–Maschine (HLM) operiert wurden. Von 1998–2002 wurden alle Bypass-Patienten die 75 Jahre und älter waren, retrospektiv aufgearbeitet. Dabei wurde entsprechend dem Euroscore und der Zahl der befallenen Gefäße eine paarweise Zuordnung vorgenommen. Die statistische Analyse erfolgte mit Student’s t–Test und Chi–Quadrat–Test. 270 Bypass–Patienten wurden aufgenommen: 135 wurden ohne und 135 mit HLM operiert. Das mittlere Alter für die Off–pump– bzw. On–pump–Gruppe lag bei 78,4 ± 3,1 versus 77,5 ± 2,9 Jahren. Der EuroSCORE lag bei 7,11 ± 2,3 in beiden Gruppen; die Zahl distaler Anastomosen pro Patient bei 1,7 ± 0,74 versus 3,1 ± 0,63 (p < 0,001) und die Operationszeit bei 138 versus 177 Minuten (p < 0,001). Bei den postoperativen Komplikationen ergaben sich keine signifikanten Unterschiede: Die Krankenhaus–Mortalität lag bei 3 versus 3,7%. Ein neu aufgetretenes Nierenversagen zeigte sich in 8,9% versus 12,1%, ein akuter Myokardinfarkt in 1,5 versus 4,4% und zentralneurologische Ereignisse in 0 versus 1,5%. Die Zahl der transfundierten Blutkonserven lag bei 2,6 ± 2,8 versus 4,6 ± 5,3 (p < 0,001). Die Intubationszeit sowie der Aufenthalt auf der Intensivstation waren in beiden Gruppen gleich. Im untersuchten Patientenkollektiv (≥ 75 Jahre) konnte durch das OPCAB–Verfahren keine Reduktion der perioperativen Morbidität und Mortalität erzielt werden. Offpump versus on–pump coronary artery bypass surgery: it still remains a matter of debate which method results in a lower incidence of perioperative morbidity and mortality. This case–matched study evaluates the outcome of elderly patients in both groups. All patients aged 75 and older, who underwent CABG from 1998 to 2002, were examined retrospectively. They were matched according to Euroscore and the number of diseased vessels. The Student’s t–test and chi–square test were used where appropriate. 270 CABG patients were considered: 135 off–pump and 135 on–pump patients. Mean age was 78.4 ± 3.1 versus 77.5 ± 2.9 years, respectively. EuroSCORE was 7.11 ± 2.3 in both groups; number of distal anastomoses per patient 1.7 ± 0.74 versus 2.6 ± 0.63 (p < 0.001), operation time 138 versus 177 minutes (p < 0.001). There were no significant differences in postoperative complications including hospital mortality 3.0 versus 3.7%, renal failure 8.9 versus 12.1% (new onset), acute myocardial infarction 1.5 versus 4.4% and cerebral events 0 versus 1.5%, respectively. The number of transfused packed cells was 2.6 ± 2.8 versus 4.6 ± 5.3 (p < 0.001). Intubation time and ICU stay were similar in both groups. OPCAB is not associated with a reduction of perioperative mortality and morbidity in patients aged 75 and older.

Extremely obese patients treated with venovenous ECMO—an intensivist’s challenge

Obesity, defined according to bodymass index (BMI N 30 kg/m), is an increasing problem in theworld’s population. The proportion of extremely obese patients (BMI N 40 kg/m) in intensive care units varies between 2.8% and 6.8 %. We report on 2 surgical patients (BMI N 70 kg/m) with postoperative acute respiratory distress syndrome (ARDS) treated with extracorporeal membrane oxygenation (ECMO). The first patient developed severe pneumonia with ARDS on the fourth day postsurgical intervention, and venovenous ECMO was performed. At 6-month follow-up after successful weaning from extracorporeal lung support and mechanical ventilation, the patient was well but required noninvasive ventilation. The second patient developed ARDS because of severe sepsis after treatment of necrotizing fasciitis. Extracorporeal lung support took 19 days. A sacral decubitus caused secondary sepsis and resulted in lethal multiorgan failure. These 2 case reports showed that venovenous ECMO represents a challenge for the entire intensive care unitteam and is feasible for extremely obese patients but not always successful. Obesity (bodymass index [BMI] N 30 kg/m) is an increasing problem in the world’s population. In 2014, 26% of adults worldwide were obese [1]. The proportion of extremely obese patients (BMI N 40 kg/m) in intensive care units varies between 2.8% and 6.8% [2–7]. A BMI higher than 40 kg/m seems to be associated with an increased risk of developing acute respiratory distress syndrome (ARDS) along with greater morbidity, length of stay, and duration of mechanical ventilation in the intensive care unit (ICU) [8]. However, extreme obesity is not a risk factor for hospital mortality in patients with acute lung failure and is not a contraindication for venovenous extracorporeal membrane oxygenation (vv ECMO) implantation [9,10].We report on 2 cases of surgically treated patients (BMI N 70 kg/m) with postoperative ARDS and ECMO support. The first patient was a 45-year-old man (180 cm tall, 250 kg, BMI 77 kg/m) with a distal tibial and fibular shaft fracture on the left side and an ankle fracture on the right, which were operatively treated with open reduction and internalfixation. The patient developed severe pneumonia with ARDS on the fourth day of hospitalization. Because of an episode of hypercapnia, intubation and mechanical ventilation were necessary. Hypercapnic lung failure persisted after 24 hours of mechanical ventilation, and vv ECMO was indicated. The cannulation was performed via the right femoral and jugular veins with 23F and 19F cannulae. The CardioHelp HLS (Maquet, Raststatt, Germany) was used. Recovery was prolonged by 2 episodes of intestinal bleeding, which were treated successfully with endoscopic clipping. The patient ☆ Conflict of interest: None http://dx.doi.org/10.1016/j.ajem.2015.03.065 0735-6757/© 2015 Elsevier Inc. All rights reserved. Please cite this article as: Ull C, et al, Extremely obese patients treated with challenge, Am J Emerg Med (2015), http://dx.doi.org/10.1016/j.ajem.2015 was able to be weaned off the respirator. Six months after his discharge from the hospital, hewaswell but still required noninvasive ventilation. The second patient was a 34-year-old man (180 cm tall, 287 kg, BMI 88.6 kg/m) with necrotizing fasciitis on his lower left limb, which was surgically treated with extensive debridement. The patient required hemofiltration because of acute kidney failure. Furthermore, he developed ARDS as a result of severe sepsis. Severe hypoxemia and hypercapnia occurred, and vv ECMO was indicated. The cannulation was performed via the right femoral and jugular veinswith 23F and 21F cannulae. Extracorporeal membrane oxygenation was removed 19 days after implantation. Oxygenation significantly improved, and the patient wasweaned off the respirator. A sacral decubitus caused secondary sepsis and resulted in lethal multiorgan failure. The treatment of extremely obese patients with vv ECMOposes a special challenge for intensivists. Radiological diagnostics are limited because tables have weight restrictions of 200 kg. It makes the use of a doublelumen cannulation not available. Percutaneous cannulation venovenous femoral-jugular is associated with several pitfalls: anatomical landmarks are difficult tofind, the blood vessels cannot be visualized sonographically, and at least 4 people from the ICU team help for patient positioning. Both patients were successfully weaned from ECMO and later from invasive ventilation. These case reports showed that extracorporeal lung support is a feasible treatment option for extremely obese patients with ARDS, a finding that was previously described [9,10]. After weaning from ECMO, 1 patient required noninvasive ventilation support; the other died of multiorgan failure due to secondary sepsis. It also demonstrated as well how difficult it is to make accurate predictions about the outcome of ECMO in patients with extreme obesity. Several studies tried to determine the risk factors associated with ECMO treatment. In an analysis of preoperative risk factors in cardiac ECMO, Wagner et al [11] showed a positive association between preoperative SvO2 and survival. Later, they [12] found that poor renal function before ECMO resulted in a higher mortality rate for patients with pulmonary failure. This association was seen in the second patient, who required hemofiltration because of acute kidney failure. Another study revealed a lowermortality rate in younger and nondiabetic patients who experienced cardiogenic shock [13]. Formica et al [14] identified a high blood lactate level (N3mmol/L) at 48 hours as a significant predictor of 30-day hospital mortality for patients with cardiogenic shock. A higher survival rate of younger patients and those with a normal blood lactate level after 24 hours of ECMO treatment was confirmed by Pham et al [15] in a study with 123 adults with ARDS caused by influenza A (H1N1). Those risk factors could not be found in either of the patients. The study by Rastan et al [16] was the only trial that identified obesity as a risk factor for hospital mortality in adult patients treated with ECMO for refractory postcardiotomy cardiogenic shock. venovenous extracorporeal membrane oxygenation—an intensivist’s .03.065 2 C. Ull et al. / American Journal of Emergency Medicine xxx (2015) xxx–xxx This case report supports the findings of previous studies in this regard that treatmentwith vv ECMO in extremely obese patients presents special challenges for the entire ICU team. Extreme obesity should not be seen as a contraindication for ECMO treatment, but the procedure should be performed by experienced hands.

Venoarterielle extrakorporale Membranoxygenierung (ECMO)

According to the guidelines of the European (2008) and German Societies of Cardiology (2009) thrombolysis is recommended for patients with pulmonary embolisms presenting with cardiogenic shock (recommendation level I, evidence level A). If there are contraindications or thrombolysis is not successful surgical embolectomy should be considered (recommendation level I, evidence level C). Additional options are catheter-based therapies in the proximal pulmonary artery (recommendation level IIb, evidence level C). The use of arteriovenous extracorporeal membrane oxygenation ( ECMO) was not included in these guidelines. A literature search in PubMed resulted in some case reports of the successful use of arteriovenous ECMO for resuscitation in patients with severe pulmonary embolisms following failed thrombolysis. In this article we present the case report of a patient who developed fulminant pulmonary embolism immediately after surgery. The patient was still in cardiogenic shock despite thrombolysis but the condition was stable following implementation of an arteriovenous ECMO. Acute heart failure and hypoxemia of all organs are the main symptoms of massive pulmonary embolisms. The use of arteriovenous ECMO represents a therapeutic option for life-threatening pulmonary embolism. A decisive factor for success is immediate diagnosis and rapid implementation of the system.

Beating-heart coronary artery bypass grafting using a miniaturized extracorporeal circulation system.

BACKGROUND Experience with miniaturized coronary artery bypass (CAB) systems in coronary artery bypass graft (CABG) surgery on the beating heart is limited. We used a relatively new miniaturized cardiopulmonary bypass (CPB) system, which we termed assisted CAB (ACAB), to perform CABG on the beating heart in 110 patients, and we analyzed clinical outcomes in this patient group. METHODS Between January 2004 and September 2006, we used ACAB to perform CABG on the beating heart in 110 patients. The mean patient age was 73 +/- 8.1 years. The ACAB system uses a small prime volume of only 500 mL, and the circuit is shorter than that used in conventional CPB. In addition, the tubing and oxygenator systems were surface-coated with phosphorylcholine. The initial heparin dose was 150 IU/kg, with a target activated clotting time of >250 seconds. With this management, none of the patients experienced system thrombosis. We did not use cardioplegia or aortic crossclamping and did not routinely retransfuse cardiotomy blood. Observational data for the 110 patients were analyzed. RESULTS The mean number of anastomoses performed was 2.67. The rate of perioperative infarction was 1.8% (2 patients). Perioperative mortality was 7% (8 patients). The mean EuroSCORE for all patients was 6.4 +/- 4, whereas it was 13.75 +/- 6.18 for the patients who died. Mean CPB time was 64.96 +/- 16.66 minutes. CONCLUSION In our experience, beating heart CABG supported by a miniaturized CPB is a safe procedure with acceptable perioperative results.

Effect of body mass index on the outcome of surgical patients receiving extracorporeal devices (VV ECMO, pECLA) for respiratory failure

Introduction To determine whether obese surgical patients are at a significant disadvantage in terms of outcomes after extracorporeal device (ECD) support, such as veno-venous extracorporeal membrane oxygenation (VV ECMO) or pumpless extracorporeal lung assist (pECLA), for respiratory failure, the relationship between body mass index (BMI) and hospital outcomes was analyzed. Methods This retrospective study included data on patients who were supported with an ECD between January 1, 2008 and December 31, 2014. The analysis included 89 patients (74 male). Results The median BMI was 30 kg/m2 (19–88.5). The median duration of the ECD support was 9.0 days, with a maximum of 37.1 days. The median LOS (length of stay) in the intensive care unit (ICU) was 21 days (range 0.06–197.6). The median hospital LOS was 34.9 days (range 0.1–213.8). VV ECMO was performed 72 times, and pECLA was performed 18 times. The number of patients successfully weaned off the ECD was 54 (60.6%). Survival at the discharge from the hospital was 48.3%. Conclusions 54 (60.6%) patients were successfully weaned off the ECD; 43 (48.3%) patients survived and were discharged from the hospital. The analysis of correlations between BMI and outcomes of surgical patients treated with ECD showed no association between BMI and mortality. Complications (especially oxygenator clotting) were not more frequent in obese and extremely obese patients. We hypothesized that patients with higher or morbid BMIs would have increased mortality after ECD support. A BMI of 30.66 kg/m2 corresponded to the desired sensitivity and specificity to predict mortality. This finding applied only to the study group. Treatment with ECD in obese patients presents unique challenges, including percutaneous cannulation and increased staff requirements. However, based on these data, obesity should not be an exclusion criterion for ECD therapy.

The impact of hypertension on the operative and early postoperative outcome of aortic valve surgery

Hypertension is a known risk factor in heart disease. It can lead to pressure overload and hypertrophy of the left ventricle. The aim of this study is to examine the effect of hypertension on the operative and early postoperative outcome after aortic valve surgery using the retrograde cardioplegia. All the data of all the patients who had aortic valve surgery in our department were retrospectively examined during the period from January 1994 until April 1996 and received retrograde blood cardioplegia. 397 patients were included in this study. 213 of them had arterial hypertension, as preoperatively diagnosed by the referring cardiologist. There were 163 females and 234 males. 142 were above 70 yr of age. 22 patients had an ejection fraction (EF) < or =0.4 and in 168 patients the LVEDP was >15 mmHg. Hypertension alone proved to be no risk factor. Decreased EF in hypertensive patients leads to an increase in the occurrence of prolonged ICU-stay, low cardiac output and neurological complications. Hypertension alone does not increase the risk of operative and early postoperative aortic valve surgery.

Goal directed perfusion to reduce acute kidney injury: A randomized trial

Objective To determine whether a goal‐directed perfusion (GDP) strategy aimed at maintaining oxygen delivery (DO2) at ≥280 mL·min−1·m−2 reduces the incidence of acute kidney injury (AKI). Methods This multicenter randomized trial enrolled a total of 350 patients undergoing cardiac surgery in 9 institutions. Patients were randomized to receive either GDP or conventional perfusion. A total of 326 patients completed the study and were analyzed. Patients in the treatment arm were treated with a GDP strategy during cardiopulmonary bypass (CPB) aimed to maintain DO2 at ≥280 mL·min−1·m−2. The perfusion strategy for patients in the control arm was factored on body surface area and temperature. The primary endpoint was the rate of AKI. Secondary endpoints were intensive care unit length of stay, major morbidity, red blood cell transfusions, and operative mortality. Results Acute Kidney Injury Network (AKIN) stage 1 was reduced in patients treated with GDP (relative risk [RR], 0.45; 95% confidence interval [CI], 0.25‐0.83; P = .01). AKIN stage 2‐3 did not differ between the 2 study arms (RR, 1.66; 95% CI, 0.46‐6.0; P = .528). There were no significant differences in secondary outcomes. In a prespecified analysis of patients with a CPB time between 1 and 3 hours, the differences in favor of the treatment arm were more pronounced, with an RR for AKI of 0.49 (95% CI, 0.27‐0.89; P = .017). Conclusions A GDP strategy is effective in reducing AKIN stage 1 AKI. Further studies are needed to define perfusion interventions that may reduce more severe levels of renal injury (AKIN stage 2 or 3).