Martin Petzoldt

Hypoxic cardiac arrest in pregnancy due to pulmonary haemorrhage

A 23-year-old woman developed massive pulmonary haemorrhage in the 19th week of pregnancy. Essential invasive ventilation was seriously impaired by the mechanical properties of the blood-filled lungs. Consecutive severe respiratory failure (pO2 10 mm Hg, pCO2 320 mm Hg, pH 6.73) induced a cardiac arrest. Bronchoscopy could not identify the source of bleeding. During 45 min of cardiopulmonary resuscitation, veno-venous extracorporeal membrane oxygenation (ECMO) was installed. Subsequently, neither a high-resolution CT (HRCT) scan nor pulmonary angiography could identify the origin of the haemorrhage. Finally, the excessive pulmonary bleeding was controlled by placing an endobronchial blocker in the middle lobe bronchus. However, pulmonary haemorrhage reoccurred and this time HRCT revealed an isolated bronchiectasis in the middle lobe. Based on this finding, surgical lobectomy was performed. The patient recovered fully without any neurological sequelae. A solitary bronchiectasis has not previously been described as a cause of massive pulmonary haemorrhage in pregnancy.

Rescue Therapy With a Pumpless Extracorporeal Lung Assist Device in a Patient With Acute Interstitial Lung Disease and Severe Refractory Hypercapnia

Idiopathic interstitial pneumonia frequently causes severe pulmonary restriction that in turn makes mechanical ventilation difficult. We report the case of a 44-year-old woman who developed a refractory severe hypercapnic respiratory failure (PaCO2 281 mm Hg, pH 6.77) despite mechanical ventilation with high inspiratory pressure and PEEP. A pumpless extracorporeal lung assist device, Novalung, was used as rescue therapy for carbon dioxide removal, enabling lung-protective ventilation and normalization of life-threatening acidosis. Open lung biopsy revealed an idiopathic interstitial pneumonia with histological features of a nonspecific interstitial pneumonia. Corticosteroid therapy led to progressive improvement of pulmonary function, soon permitting cessation of mechanical ventilation and extracorporeal therapy. The patient was discharged from the intensive care unit after 20 days. This case demonstrates the successful use of pumpless extracorporeal lung assist as an alternative device to pump-driven extracorporeal membrane oxygenation in severe hypercapnic respiratory failure secondary to nonspecific interstitial pneumonia.

Dynamic device properties of pulse contour cardiac output during transcatheter aortic valve implantation

This prospective single-center study aimed to determine the responsiveness and diagnostic performance of continuous cardiac output (CCO) monitors based on pulse contour analysis compared with invasive mean arterial pressure (MAP) during predefined periods of acute circulatory deterioration in patients undergoing transcatheter aortic valve implantation (TAVI). The ability of calibrated (CCOCAL) and self-calibrated (CCOAUTOCAL) pulse contour analysis to detect the hemodynamic response to 37 episodes of balloon aortic valvuloplasty enabled by rapid ventricular pacing was quantified in 13 patients undergoing TAVI. A “low” and a “high” cut-off limit were predefined as a 15 or 25 % decrease from baseline respectively. We found no significant differences between CCOCAL and MAP regarding mean response time [low cut-off: 8.6 (7.1–10.5) vs. 8.9 (7.3–10.8) s, p = 0.76; high cut-off: 11.4 (9.7–13.5) vs. 12.6 (10.7–14.9) s, p = 0.32] or diagnostic performance [area under the receiver operating characteristics curve (AUC): 0.99 (0.98–1.0) vs. 1.0 (0.99–1.0), p = 0.46]. But CCOCAL had a significantly higher amplitude response [95.0 (88.7–98.8) % decrease from baseline] than MAP [41.2 (30.0–52.9) %, p < 0.001]. CCOAUTOCAL had a significantly lower AUC [0.83 (0.73–0.93), p < 0.001] than MAP. Moreover, CCOCAL detected hemodynamic recovery significantly earlier than MAP. In conclusion, CCOCAL and MAP provided equivalent responsiveness and diagnostic performance to detect acute circulatory depression, whereas CCOAUTOCAL appeared to be less appropriate. In contrast to CCOCAL the amplitude response of MAP was poor. Consequently even small response amplitudes of MAP could indicate severe decreases in CO.

Is applanation tonometry a reliable method for monitoring blood pressure in morbidly obese patients undergoing bariatric surgery

BACKGROUND The aim of this study was to evaluate the validity of non-invasive continuous BP measurement by applanation tonometry in morbidly obese patients undergoing bariatric surgery. METHODS Arterial blood pressure (AP) was recorded intraoperatively both by applanation tonometry (AT) (T-Line 200pro, Tensys Medical(®), USA) and an arterial line (AL) after radial cannulation in obese patients undergoing bariatric surgery. Discrepancies between the two methods were assessed as bias, limits of agreement and percentage error. Mean, systolic, and diastolic arterial pressures were assessed (MAP, SAP, DAP respectively). Trending ability was assessed by concordance based on four-quadrant plotting. RESULTS Mean (sd) BMI of the 28 patients was 49.4 (9.7 kg m(-2)). A total of 201 907 time points were available for analysis. Bias for MAPAT compared with MAPAL was +3.97 mm Hg (SAPAT +3.45 mm Hg; DAPAT +3.66 mm Hg) with limits of agreement for MAPAT of -14.47 and +22.41 mm Hg (SAPAT -22.0 and +28.9 mm Hg; DAPAT -15.7 and +23.1 mm Hg). Percentage error for MAPAT was 23.5% (23.4% for SAPAT; 30.5% for DAPAT). Trending ability for MAP, SAP, and DAP revealed a concordance of 0.74, 0.72, and 0.71, respectively. CONCLUSIONS Continuous BP assessment by applanation tonometry is feasible in morbidly obese patients undergoing bariatric surgery. However, despite a low mean difference, 95% limits of agreement and trending ability indicate that the technology needs to be improved further, before being recommended for routine use in this group of patients.

Cardiac output monitoring in severe aortic stenosis: Which technologies are reliable?

The prevalence of valvular heart diseases is rising rapidly in industrialized countries as a result of demographic changes. Due to its degenerative genesis, aortic stenosis (AS) is frequently diagnosed in the elderly with a prevalence of more than 10 % in patients aged over 85 years. Novel and successful treatment concepts of AS have been developed in the last decade. Aortic valve replacement (AVR) has been shown to increase life expectancy even in patients over 80, and transcatheter aortic valve implantation (TAVI) has become an established treatment in multimorbid patients who were regarded as inoperable in the past [1]. Consequently, we see patients with AS much more often in perioperative and intensive care medicine. Adequate perioperative hemodynamic monitoring is essential in such a high-risk population. However, evidence about whether we can rely on the increasingly used less-invasive monitoring technologies in this subpopulation is scarce. Currently we tend to extrapolate conclusions drawn from validation studies in unselected patients to the subgroup of patients with AS. But aortic valve dysfunctions are known to influence decisively the hemodynamic signals on which most less-invasive hemodynamic monitoring devices rely. So where do we stand with regard to cardiac output (CO) monitoring in AS? Traditionally, transoesophageal echocardiography (TEE), thermodilution via a pulmonary artery catheter (PAC), and transcardiopulmonary thermodilution (TPTD) have been advocated as standard reference methods to determine CO and stroke volume (SV) in patients with AS, although interestingly there are very few data from well performed studies to support this recommendation [2]. However, all these methods only provide intermittent measurements and are therefore unable to track acute hemodynamic changes, which limits their benefit for immediate clinical decision making in situations of hemodynamic instability [3]. This limitation could be overcome by less-invasive continuous cardiac output (CCO) monitoring technologies, which have been introduced to the clinic in recent decades. Arterial pulse contour analysis (PC) as well as oesophageal doppler monitoring (ODM) are designed to continuously track CCO and SV in a beat-to-beat fashion. However, as mentioned, AS is believed to distort exactly those signals on which both techniques rely. Autocalibrated PC (SVVig) and ODM with the CardioQ-device (SVOD) require self-calibration, which incorporates demographic data from a wide range of patients of varying age, sex, weight, height, and ethnic origin. But it is not known if these algorithms, which were developed for automated signal analysis [i.e. arterial pressure waveform (PC) or aortic blood flow velocity analysis (ODM)], do perform adequately in the particular pathophysiologic framework found in AS, where the interactions between cardiac performance, systemic blood flow, perfusion pressure, peripheral arterial resistance and compliance are altered. SVOD uses the area under the maximum velocity curve in the descending thoracic aorta during systole and incorporates nomograms based on biometric data to predict the descending aorta cross sectional area (CSA) as well as the distribution of blood flow through the body (approximately & Martin Petzoldt m.petzoldt@uke.de

Heparin-induced thrombocytopenia associated with acute liver graft failure

An orthotopic liver transplantation (OLT) is of a proven benefit in an acute liver failure (ALF). Heparin-induced thrombocytopenia (HIT) is strongly associated with thromboembolic complications. We present the case of a 56-year-old patient who underwent an OLT owing to an ALF of unknown aetiology. HIT type II with consecutive hepatic and portal vein thrombosis caused progressive graft failure. Total hepatectomy and porto-caval shunt were performed to reduce the toxic effects of liver cell necrosis such as multiorgan failure involving the respiratory, renal and cardiovascular systems. A suitable liver graft was allocated after an anhepatic bridging period of 56 h. Specific complications due to end-stage liver failure—such as acidosis, coagulopathy, decrease of vascular resistance, cerebral oedema, myocardial infarction and right heart failure—were treated. Following a re-OLT, the patient made a complete recovery. We present a rare case of HIT-associated early liver graft failure followed by a prolonged anhepatic phase and finally a successful re-OLT.

Reliability of transcardiopulmonary thermodilution cardiac output measurement in experimental aortic valve insufficiency

Background Monitoring cardiac output (CO) is important to optimize hemodynamic function in critically ill patients. The prevalence of aortic valve insufficiency (AI) is rising in the aging population. However, reliability of CO monitoring techniques in AI is unknown. The aim of this study was to investigate the impact of AI on accuracy, precision, and trending ability of transcardiopulmonary thermodilution-derived COTCPTD in comparison with pulmonary artery catheter thermodilution COPAC. Methods Sixteen anesthetized domestic pigs were subjected to serial simultaneous measurements of COPAC and COTCPTD. In a novel experimental model, AI was induced by retraction of an expanded Dormia basket in the aortic valve annulus. The Dormia basket was delivered via a Judkins catheter guided by substernal epicardial echocardiography. High (HPC), moderate (MPC) and low cardiac preload conditions (LPC) were induced by fluid unloading (20 ml kg-1 blood withdrawal) and loading (subsequent retransfusion of the shed blood and additional infusion of 20 ml kg-1 hydroxyethyl starch). Within each preload condition CO was measured before and after the onset of AI. For statistical analysis, we used a mixed model analysis of variance, Bland-Altman analysis, the percentage error and concordance analysis. Results Experimental AI had a mean regurgitant volume of 33.6 ± 12.0 ml and regurgitant fraction of 42.9 ± 12.6%. The percentage error between COTCPTD and COPAC during competent valve function and after induction of substantial AI was: HPC 17.7% vs. 20.0%, MPC 20.5% vs. 26.1%, LPC 26.5% vs. 28.1% (pooled data: 22.5% vs. 24.1%). The ability to trend CO-changes induced by fluid loading and unloading did not differ between baseline and AI (concordance rate 95.8% during both conditions). Conclusion Despite substantial AI, transcardiopulmonary thermodilution reliably measured CO under various cardiac preload conditions with a good ability to trend CO changes in a porcine model. COTCPTD and COPAC were interchangeable in substantial AI.

How precise is “precision” of hemodynamic measurements in clinical validation studies?

Dear Editor, We thank Hunsicker and coworkers [1] for their interest in our clinical study evaluating the influence of aortic valve dysfunction on stroke volume determination by transcardiopulmonary thermodilution (TPTD) and pulse contour analysis [2]. Although Hunsicker et al. [1] misinterpret our study as a validation study comparing TPTD with transesophageal echocardiography (TEE), they touch on a crucial point by emphasizing the importance of the precision of the different cardiac output (CO) measurement technologies in method comparison studies. Indeed, when using the percentage error (PE) proposed by Critchley and Critchley, the PE threshold used to define acceptable agreement can only be interpreted in the context of both the precision of the reference technology (RT) and the precision of the study technology (ST) [3]. The term ‘‘precision’’ is defined as the variability of data due to random errors with the coefficient of error (CE) calculated as the standard deviation divided by the mean for replicated numbers of measurements. However, with regard to clinical studies aiming to compare different hemodynamic measurement technologies it has to be emphasized that the reliable assessment of the precision of the technologies at the bedside is outstandingly complex [4]. Moreover, the true precision of the RT remains unknown in many of these validation studies [4]. Therefore, to be able to compare the rapidly increasing number of clinical studies comparing one hemodynamic monitoring system with another, we need to find a consensus on how to separately assess and report precision of the technologies in a clinical setting. As long as we do not agree on these basic definitions, scientists, reviewers, and editors in this field risk that study results will be misinterpreted. Regarding the second remark by Hunsicker et al., we used ‘‘full circle polar plots’’—exactly as proposed by Critchley et al. [5] in 2010—to illustrate trending ability of the applied monitoring devices. Agreement is shown by the angle and the magnitude of change by the length of the vector. These plots use horizontal limit lines. Good or acceptable trending can be assumed if most data points lie within a 10 or 20 % boundary, respectively [5]. Readers should note that these polar plots should not be confused with ‘‘half circle polar plots with a central exclusion zone’’, published by Critchley and coworkers in 2011, which imply a ±30 radial limit of agreement. Conflicts of interest D.A.R. and B.S. are members of the Medical Advisory Board of Pulsion Medical Systems SE (Feldkirchen, Germany). M.P. has declared no conflict of interest.

Perioperative medikamentöse Kardioprotektion

ZusammenfassungSchwere perioperative Komplikationen bei kardialen Hochrisikopatienten sind häufig und mit einer hohen Letalität verbunden. Die Studienlage für eine perioperative β-Blocker-Therapie ist heterogen, und teilweise divergierende Ergebnisse machen eine umsichtige Interpretation erforderlich, insbesondere wenn hieraus globale therapeutische Empfehlungen für viele Millionen Patienten abgeleitet werden. Für eine perioperative β-Blocker-Therapie besteht nur bei einer limitierten Subpopulation kardialer Hochrisikopatienten – insbesondere bei gefäßchirurgischen Eingriffen – eine ausreichende Evidenz. Perioperative β-Blocker sind bei Patienten mit moderatem Risiko neutral und bei Patienten mit niedrigem Risiko sogar potenziell schädlich. Der Schlüssel für eine rationale Therapie ist daher eine individuelle differenzierte Nutzen-Risiko-Bewertung. Diese erfolgt als standardisiertes protokollbasiertes kardiales Screening; ein hierfür entworfener Evaluationsbogen wird vorgestellt. Als zentrales Scoresystem kann der Revised Cardiac Risk Index nach Lee (RCRI) empfohlen werden. Eine aktuelle Studie (POISE) demonstriert, dass eine relativ hoch dosierte orale perioperative Metoprololtherapie die Inzidenz kardiovaskulärer Ereignisse effektiv senkt. Jedoch wird die Gesamtletalität aufgrund erheblicher Nebenwirkungen (Hypotension, Bradykardie, Schlaganfall) erhöht. Ein besonderes Augenmerk ist daher auf die Dosisanpassung und die Sicherheitsaspekte einer β-Blocker-Therapie sowie auf das flankierende Monitoring zu richten. Clonidin ist ein Alternativpräparat bei Patienten mit zusätzlichen pulmonalen Risikofaktoren. Bestehende Studien geben keinen Anhalt dafür, wie eine medikamentöse Kardioprotektion in den perioperativen Prozess implementiert werden kann. Dieser Artikel stellt hierfür ein einfaches klinisches Konzept vor.AbstractPatients with major cardiac risk factors have been suggested to benefit from perioperative β-blockade. However, the scientific literature on perioperative β-blockade needs to be interpreted carefully. So far treatment recommendations for millions of patients are based on heterogeneous data from randomized trials with divergent study results. The evidence for a beneficial effect of perioperative β-blockers is sufficient only for a limited subpopulation of high cardiac risk patients undergoing vascular surgery. Perioperative β-blocker treatment is not useful in patients with intermediate risk and may even be harmful in patients with low cardiac risk. Therefore, an individualized risk-benefit analysis is an important prerequisite for a rational therapy that may be based on a standardized protocol including the Revised Cardiac Risk Index. Such a protocol is presented in this article. A recently reported trial (POISE) demonstrated that perioperative treatment with high doses of oral metoprolol efficiently reduces the incidence of cardiovascular events. However, due to severe adverse effects (hypotension, bradycardia, stroke) the total mortality was increased. Thus, dose adjustments, safety aspects, and monitoring of β-blocker therapy seem to be mandatory. So far evidence from relevant trials about how to best implement perioperative β-blockade is lacking. This article offers a simple clinical concept for this purpose.Patients with major cardiac risk factors have been suggested to benefit from perioperative beta-blockade. However, the scientific literature on perioperative beta-blockade needs to be interpreted carefully. So far treatment recommendations for millions of patients are based on heterogeneous data from randomized trials with divergent study results. The evidence for a beneficial effect of perioperative beta-blockers is sufficient only for a limited subpopulation of high cardiac risk patients undergoing vascular surgery. Perioperative beta-blocker treatment is not useful in patients with intermediate risk and may even be harmful in patients with low cardiac risk. Therefore, an individualized risk-benefit analysis is an important prerequisite for a rational therapy that may be based on a standardized protocol including the Revised Cardiac Risk Index. Such a protocol is presented in this article. A recently reported trial (POISE) demonstrated that perioperative treatment with high doses of oral metoprolol efficiently reduces the incidence of cardiovascular events. However, due to severe adverse effects (hypotension, bradycardia, stroke) the total mortality was increased. Thus, dose adjustments, safety aspects, and monitoring of beta-blocker therapy seem to be mandatory. So far evidence from relevant trials about how to best implement perioperative beta-blockade is lacking. This article offers a simple clinical concept for this purpose.

Aspirin Before Elective Surgery—Stop or Continue?

BACKGROUND Cessation of long-term aspirin treatment before noncardiac surgery can cause adverse cardiac events in patients at risk, particularly in those with previous percutaneous coronary interventions (PCI) with stent implantation. The factors influencing the clinical decision to stop aspirin treatment are currently unknown. METHODS In a single-center, cross-sectional study (retrospective registration: NCT03049566) carried out from February to December 2014, we took a survey among patients scheduled for noncardiac surgery who were under long-term aspirin treatment, and among their treating anesthesiologists using standardized questionnaires on preoperative aspirin use, comorbidities, and risk-benefit assessments. The main objective was to identify factors associated with the decision to stop aspirin treatment. The results of multivariable logistic regressions and intraclass correlations are presented. RESULTS 805 patients were included in the study, and 636 questionnaires were returned (203 of which concerned patients with coronary stents). 46.8% of the patients stopped their long-term aspirin treatment before surgery; 38.7% of these patients stopped it too early (>10 days before surgery) or too late (≤ 3 days before surgery). A prior PCI with stent implantation lowered the probability of aspirin cessation (odds ratio [OR] = 0.47 [0.31; 0.72]; p <0.001). On the other hand, patients were more likely to stop their long-term aspirin treatment if it had already been discontinued once before (OR = 4.58 [3.06; 6.84]; p <0.001), if there was a risk of bleeding into a closed space (OR = 4.54 [2.02; 10.22]; p <0.001), if they did not know why they were supposed to take aspirin (OR = 2.12 [1.05; 4.28]; p = 0.036), or if the preoperative consultation with the anesthesiologist occurred <2 days before surgery (OR = 1.60 [1.08; 2.37]; p = 0.018). Patients often assessed the risks related to aspirin cessation lower than their physicians did. CONCLUSION This study reveals discordance between guideline recommendations and everyday clinical practice in patients with coronary stents. The early integration of cardiologists and anesthesiologists and a more widespread use of stent implant cards could promote adherence to the guidelines.