Progress in the management of acute pulmonary embolism:

Intensive Care Treatment of Pulmonary Embolism: An Update Based on the Revised AWMF S2k Guideline

Acute pulmonary embolism (PE) remains a significant cause of morbidity and requires prompt diagnosis and management. The prognosis of affected patients depends on the clinical severity. Therefore, risk stratification is imperative for therapeutic decision-making. Patients with high-risk PE need intensive care. These include patients who have successfully survived resuscitation, with obstructive shock or persistent haemodynamic instability. Bedside diagnostics by means of sonographic procedures are of outstanding importance in this high-risk population. In addition to the treatment of hypoxaemia with noninvasive and invasive techniques, the focus is on drug-based haemodynamic stabilisation and usually requires the elimination or reduction of pulmonary vascular thrombotic obstruction by thrombolysis. In the event of a contraindication to thrombolysis or failure of thrombolysis, various catheter-based procedures for thrombus extraction and local thrombolysis are available today and represent an increasing alternative to surgical embolectomy. Mechanical circulatory support systems can bridge the gap between circulatory arrest or refractory shock and definitive stabilisation but are reserved for centres with the appropriate expertise. Therapeutic strategies for patients with intermediate- to high-risk PE in terms of reduced-dose thrombolytic therapy or catheter-based procedures need to be further evaluated in prospective clinical trials.

A new method of CT for the cardiac measurement: correlation of computed tomography measured cardiac parameters and pulmonary obstruction index to assess cardiac morphological changes in acute pulmonary embolism patients

Acute pulmonary embolism (APE) is a serious disease which is life-threatening. Since it is crucial for APE patients to assess the changes of cardiac function safely and timely, the imaging research of cardiac morphology and function is becoming more and more important. The correlation of computed tomography (CT) measured cardiac parameters and pulmonary obstruction index (POI) was analyzed to discuss the morphological changes of the heart of APE patients in order to provide a new method to evaluate cardiac functions accurately and effectively. 118 APE patients confirmed with CT pulmonary angiography (CTPA) were divided into high-risk group (47 cases, POI ≥ 20) and low-risk group (71 cases, POI < 20) according to the Qanadli Score. The left to right diameter (RL) and the anteroposterior diameter (AP) of the cardiac chambers were compared among the high-risk group, the low-risk group, and the normal group (60 cases). The correlation between CT measured cardiac parameters and the POI was analyzed. Except for left ventricular AP and right atrial AP, there were statistically significant differences (P < 0.05) in the RL and AP of the each cardiac cavity, these parameters meant that right hearts were enlarged and the left hearts were decreased in size. The ratio of right/left heart diameter was statistically significant among the three groups, a < b < c (P < 0.05). Moreover, the POI of 118 APE patients was 14.29 ± 9.53, and there was significant linear correlation between CT measured cardiac parameters and the POI (P < 0.05), excluding the left ventricular AP and right atrial AP. The correlation coefficient reached 0.5 or more in terms of the right atrial LR, the right ventricular LR, the ratio of right/left atrial diameter and the ratio of right/left ventricular diameter. With the increasing value of POI, the right atrium and right ventricular of APE patients were enlarged, and the left atrium and left ventricular were decreased in size. These heart changes can be observed by using CTPA, even non-enhanced chest CT.

Clinical value of cardiac color ultrasound and cardiac troponin T combined with dynamic electrocardiogram in treatment of acute pulmonary embolism

The clinical value of cardiac color ultrasound and cardiac troponin T (cTnT) combined with dynamic electrocardiogram in evaluating the treatment effect on acute pulmonary embolism (APE) was investigated. Ninety-eight patients with APE treated in Jinan Zhangqiu District Hospital of TCM from March 2016 to February 2017 were selected, and they were examined via the cardiac color ultrasound, cTnT and dynamic electrocardiogram to evaluate the clinical value in the treatment of pulmonary embolism. Electrocardiogram showed that there was no significant difference in the poor prognosis rate between right ventricular strain group and non-right ventricular strain group (P>0.05); the poor prognosis rate in cTnT positive group was significantly higher than that in cTnT negative group (P<0.05). Moreover, the ultrasonic cardiogram revealed that the poor prognosis rate in right ventricular dysfunction group was significantly higher than that in non-right ventricular dysfunction group (P<0.05). It was found in the receiver operating characteristic (ROC) curve analysis that the areas under the curve (AUC) of ROC detected via cardiac color ultrasound and cTnT were >0.9, while that detected via dynamic electrocardiogram was <0.7. Besides, logistic regression analysis showed that cTnT and right ventricular dysfunction were the risk factors affecting the poor prognosis of patients with APE (P<0.05). In conclusion, cardiac color ultrasound can predict the prognosis of patients with APE through monitoring the right ventricular function; cTnT can also evaluate the prognosis of APE; but the electrocardiogram has little significance in evaluating the prognosis of APE.

Recent Updates of the Diagnosis and Prevention of Venous Thromboembolism in Patients with a Hip Fracture

Venous thromboembolism (VTE) is a potentially fatal complication that is relatively common after hip surgery. Since patients with a hip fracture have a higher risk of preoperative VTE due to an inability to ambulate after injury and aggravation of underlying age-related conditions, it may be difficult to effectively prevent VTE using only conventional approaches. Very few studies have been published reporting on the prevalence and prevention of VTE in patients with a hip fracture compared to those with hip arthroplasty. For this reason, we aimed to share recent updates on the diagnosis and prevention of VTE in patients with a hip fracture. Preoperative screening tests to diagnose VTE need to be performed more actively following hip fracture and indirect multidetector computed tomography venography is considered the most effective test for this purpose. As the risk of VTE appears to increase with time following a hip fracture, preventive measures should be taken as soon as possible in patients with a hip fracture. A wide variety of mechanical and pharmacological options are available for prophylaxis. When considering patient compliance and preventive impact, intermittent pneumatic compression devices and foot pumps are recommended as mechanical modalities. Of the available preventive medications for patients with a hip fracture, low molecular weight heparin seems to be the most appropriate option because of its short half-life and fast onset of action. Surgery should be performed as soon as possible in patients with hip fractures, and we recommend mechanical and pharmacological methods as active interventions immediately after injury to prevent VTE.

[Bilateral proximal pulmonary embolism without associated hypoxemia. Case report]

INTRODUCTION

Pulmonary embolism is a classic complication in intensive care. It is characterized by hypoxemia secondary to perturbed ventilation/perfusion ratios. We report a case of proximal and bilateral pulmonary embolism that occurred without associated hypoxemia. A spiral computed tomography (CT) scan was performed to explore unexplained fever in a patient with a negative infectious investigation. We discuss the mechanisms underlying the absence of hypoxemia in this patient.

CLINICAL CASE

A 43-year-old patient with no significant pathological history was admitted to intensive care for the management of multiple injuries following a road accident. During resuscitation, the patient developed a proximal and bilateral pulmonary embolism without signs of hypertension of the pulmonary artery or associated hypoxemia. The patient improved under treatment.

DISCUSSION

This case shows that bilateral proximal pulmonary embolism may be associated with normal gas exchange. The absence of hypoxemia could be explained by the bilateral nature of the pulmonary embolism that led to balanced ventilation/perfusion ratios on both sides. Furthermore, bronchoconstriction was bilateral, explaining the maintenance of a stable ventilation/perfusion ratio on both sides.

CONCLUSION

The presence of unexplained fever in a victim of multiple trauma, despite the absence of hypoxemia, suggests the diagnosis of pulmonary embolism.

Terapia fibrinolítica sistêmica no tromboembolismo pulmonar

O tromboembolismo pulmonar permanece como um grande desafio terapêutico para os médicos especialistas, pois, apesar de todo investimento e desenvolvimento em seu diagnóstico, profilaxia e tratamento, essa condição continua sendo a principal causa de morte evitável em ambiente hospitalar. Ainda restam muitas dúvidas em relação a qual perfil de paciente vai se beneficiar de fato da terapia fibrinolítica sistêmica, sem ficar exposto a um grande risco de sangramento. A estratificação de risco e a avaliação do prognóstico do evento, através de escores clínicos de insuficiência ventricular direita, marcadores de dilatação e disfunção do ventrículo direito e avaliação da massa trombótica, associados ou de forma isolada, são ferramentas que podem auxiliar na identificação do paciente que irá se beneficiar dessa terapia. Os únicos consensos em relação à terapia fibrinolítica no tratamento do tromboembolismo pulmonar são: não deve ser indicada de forma rotineira; nenhum dos escores ou marcadores, isoladamente, devem justificar seu uso; e os pacientes com instabilidade hemodinâmica são os mais beneficiados. Além disto, deve-se avaliar cada caso em relação ao risco de sangramento, especialmente no sistema nervoso central.

Study of Cardiac Arrest Caused by Acute Pulmonary Thromboembolism and Thrombolytic Resuscitation in a Porcine Model

Background:

The success rate of resuscitation in cardiac arrest (CA) caused by pulmonary thromboembolism (PTE) is low. Furthermore, there are no large animal models that simulate clinical CA. The aim of this study was to establish a porcine CA model caused by PTE and to investigate the pathophysiology of CA and postresuscitation.

Methods:

This model was induced in castrated male pigs (30 ± 2 kg; n = 21) by injecting thrombi (10–15 ml) via the left external jugular vein. Computed tomographic pulmonary angiography (CTPA) was performed at baseline, CA, and return of spontaneous circulation (ROSC). After CTPA during CA, cardiopulmonary resuscitation (CPR) with thrombolysis (recombinant tissue plasminogen activator 50 mg) was initiated. Hemodynamic, respiratory, and blood gas data were monitored. Cardiac troponins T, cardiac troponin I, creatine kinase-MB, myoglobin, and brain natriuretic peptide (BNP) were measured by enzyme-linked immunosorbent assay. Data were compared between baseline and CA with paired-sample t-test and compared among different time points for survival animals with repeated measures analysis of variance.

Results:

Seventeen animals achieved CA after emboli injection, while four achieved CA after 5–8 ml more thrombi. Nine animals survived 6 h after CPR. CTPA showed obstruction of the pulmonary arteries. Mean aortic pressure data showed occurrence of CA caused by PTE (Z = −2.803, P = 0.002). The maximal rate of mean increase of left ventricular pressure (dp/dt_max) was statistically decreased (t = 6.315, P = 0.000, variation coefficient = 0.25), and end-tidal carbon dioxide partial pressure (PetCO₂) decreased to the lowest value (t = 27.240, P = 0.000). After ROSC (n = 9), heart rate (HR) and mean right ventricular pressure (MRVP) remained different versus baseline until 2 h after ROSC (HR, P = 0.036; MRVP, P = 0.027). Myoglobin was statistically increased from CA to 1 h after ROSC (P = 0.036, 0.026, 0.009, respectively), and BNP was increased from 2 h to 6 h after ROSC (P = 0.012, 0.014, 0.039, respectively).

Conclusions:

We established a porcine model of CA caused by PTE. The dp/dt_max and PetCO₂ may be important for the occurrence of CA, while MRVP may be more important in postresuscitation.