Paradoxical hemodynamic instability complicating pericardial window surgery for cardiac tamponade in a cancer patient

Paradoxical hemodynamic instability is defined as unexpected hemodynamic compromise that develops in a patient after pericardial fluid drainage. The overall incidence of the condition is about 5%, and it has a high in-hospital mortality rate. The condition has been reported to occur regardless of the approach that is used to drain the fluid or the underlying cause of the disease. The pathophysiology of paradoxical hemodynamic instability and the appropriate intervention are not very clear, and further studies are needed to identify appropriate preventive measures.We report a rare manifestation of paradoxical hemodynamic instability in a 65-year-old woman who had a history of stage IV lung cancer. She presented with a one-week history of pleuritic chest pain and shortness of breath on exertion. Echocardiography revealed a large circumferential pericardial effusion with right atrial and ventricular collapse during diastole, suggesting a compressive effect of the pericardial fluid; however, left ventricular systolic function was well preserved. The patient underwent the scheduled creation of a subxiphoid pericardial window. Immediately after the pericardial fluid was evacuated, her heart began to beat more vigorously, but this was abruptly followed by an episode of asystole. Pacing and medical therapy were unsuccessful in preventing repeated episodes of asystole, and the patient died.To our knowledge, this is the 2nd report of unexpected asystole after the creation of a subxiphoid pericardial window, and it is the first report of a takotsubo-like contractile pattern associated with paradoxical hemodynamic instability.

Cardiac tamponade: atypical presentations after cardiac surgery

We present two cases of cardiac tamponade presenting in the aftermath of cardiac surgery. We have briefly discussed the aetiology, presentation, diagnosis and management of the condition with emphasis on its atypical presentation in postoperative patients. A high index of suspicion and early access to echocardiography is necessary for prompt recognition and treatment of this life threatening emergency.

Progression of low-pressure to acute classic cardiac tamponade-a diagnostic dilemma in the setting of spontaneous left ventricular rupture

Cardiac tamponade (CT) is a pathophysiologic continuum where hemodynamic embarrassment occurs as a result of progressive, decreased venous return that impairs diastolic ventricular filling, which in turn, when uncorrected, severely compromises cardiac output. While CT is classically associated with high intrapericardial pressures due to rapidly accumulating large pericardial effusions, low-pressure CT is a recognized entity in which a comparatively low intrapericardial pressure could result in cardiac chamber compression and subsequent cardiovascular collapse. In this article, we highlight a previously unreported scenario of rapidly re-accumulating, acute CT in the setting of left ventricular rupture in a patient who had presumably presented with low-pressure CT due to hemoperiardium.

Systolic time intervals in cardiac tamponade

Systolic time intervals (STI) have been measured in three patients with cardiac tamponade. The left ventricular ejection time (LVET), the preejection period (PEP) and the ratio PEP/LVET deviated significantly from the normal values. All three parameters improved immediately after pericardiocentesis and aspiration. The total electromechanical systole changed to only a minor degree. Measurement of STI may be a valuable tool in the diagnosis and treatment of cardiac tamponade.

Left ventricular diastolic collapse in low-pressure cardiac tamponade

A case of systemic hypotension with volume depletion not responding to intravenous fluids was found to have features of cardiac tamponade on two-dimensional (2-D) echocardiography. Intracardiac pressures were normal on cardiac catheterization. An interesting observation was the presence of left ventricular (LV) collapse on 2-D echocardiography. To the authors' best knowledge, such a case of low pressure cardiac tamponade with LV collapse has not been reported earlier.

Survival without surgical repair of acute rupture of the right ventricular free wall

Rupture of the myocardial free wall is an infrequent complication of acute myocardial infarction. Unless it occurs in a space confined by pericardial adhesions, only surgical emergency repair of ruptured myocardium can prevent death. In this paper we report the case of an 81-year-old woman who was admitted to the emergency room with cardiac tamponade, resulting from inferolateral acute myocardial infarction and a subsequent rupture of the right ventricular free wall, with the formation of pericardial thrombus and effusion. The patient refused to undergo any surgical or invasive intervention, and therefore she was only treated conservatively. Nevertheless, her condition improved dramatically, as her blood pressure increased and echocardiography abnormalities almost disappeared. Follow-up echocardiography 7 months post discharge was unremarkable. We believe that this rare case emphasizes that in special circumstances, such as creation of a thrombus that prevents more blood from extravasating, free-wall rupture without surgical repair is compatible with long-term survival.

Tezosentan normalizes hepatomesenteric perfusion in a porcine model of cardiac tamponade

BACKGROUND

To investigate endothelin-1 (ET-1)-dependent hepatic and mesenteric vasoconstriction, and oxygen and lactate fluxes in an acute, fixed low cardiac output (CO) state.

METHODS

Sixteen anesthetized, mechanically ventilated pigs were studied. Cardiac tamponade was established to reduce portal venous blood flow (Q(PV)) to 2/3 of the baseline value. CO, hepatic artery blood flow (Q(HA)), Q(PV), hepatic laser-Doppler flow (LDF), hepatic venous and portal pressure, and hepatic and mesenteric oxygen and lactate fluxes were measured. Hepatic arterial (R(HA)), portal (R(HP)) and mesenteric (R(mes)) vascular resistances were calculated. The combined ET(A)-ET(B) receptor antagonist tezosentan (RO 61-0612) or normal saline vehicle was infused in the low CO state. Measurements were made at baseline, after 30, 60, 90 min of tamponade, and 30, 60, 90 min following the infusion of tesozentan at 1 mg/kg/h.

RESULTS

Tamponade decreased CO, Q(PV), Q(HA), LDF, hepatic and mesenteric oxygen delivery, while hepatic and mesenteric oxygen extraction and lactate release increased. R(HA), R(HP) and R(mes) all increased. Ninety minutes after tesozentan, Q(PV), LDF and hepatic and mesenteric oxygen delivery and extraction increased approaching baseline values, but no effect was seen on CO or Q(HA). Hepatic and mesenteric handling of lactate converted to extraction. R(HA), R(HP) and R(mes) returned to baseline values. No changes were observed in these variables among control animals not receiving tesozentan.

CONCLUSION

In a porcine model of acute splanchnic hypoperfusion, unselective ET-1 blockade restored hepatomesenteric perfusion and reversed lactate metabolism. These observations might be relevant when considering liver protection in low CO states.

Neural drive and electromechanical alterations in the fatiguing diaphragm

It is suggested that respiratory failure in the compromised circulation might occur as a result of respiratory muscle fatigue in the presence of adequate neural drive and muscle excitation. As the cardiac output decreases acidosis develops and ventilation increases, resulting in an increase in the work of breathing, which requires the delivery of large supplies of energy. As these demands cannot be met by the energy supply, because of low cardiac output, the diaphragm fails as a force generator and respiratory failure ensues. Diaphragmatic fatigue may occur in normal subjects if the pressure developed with each breath is greater than 40% of the maximum transdiaphragmatic pressure and hypoxia predisposes the diaphragm to fatigue. Diaphragmatic fatigue, as in other skeletal muscles, might be located either at the neuromuscular junction or distal to it and can be detected either by phrenic stimulation or by frequency analysis of the myoelectric signal. Phrenic stimulation shows that after fatigue the diaphragm develops less force at any frequency of stimulation, but the loss of force at low frequencies persists for a longer period than at high frequencies. Frequency analysis of the electromyogram reveals that the power spectrum shifts to lower frequencies. This shift occurs long before the diaphragm fails as a force generator.

Acute cardiac tamponade: anticipate the complication

Acute cardiac tamponade (ACT) is a serious complication following cardiac surgery. ACT occurs as a result of post-operative bleeding in the first five to seven days following the operative procedure. Although the incidence of ACT is relatively low, the consequences include cardiac compromise and even death. This article includes a review of the pathophysiology, assessment, prevention, signs, diagnosis, and management strategies for patients who develop ACT The knowledge gleaned from this article will enable the critical care nurse to anticipate and prevent this life-threatening complication and, thus, optimize outcomes for this complex surgical population.

A child with pericardial effusion and cardiac tamponade due to previously unrecognized hypothyroidism

We present a 12-year-old Hispanic girl without overt symptoms of hypothyroidism who presented with early cardiac tamponade from pericardial effusion due to previously unrecognized hypothyroidism. Pediatric patients with unexplained pericardial effusions should be screened for hypothyroidism and should be followed closely for the development of tamponade if found to have hypothyroidism.

[Preoperative pulseless electrical activity of acute type A aortic dissection; report of a case]

An 80-year-old man with acute type A aortic dissection, who was preoperatively observed in the intensive care unit, suddenly became unresponsive. The patient was immediately intubated, but a pulse check was delayed because the cardiac monitor seemingly showed a normal sinus rhythm. Bedside echocardiography, while continuing cardiopulmonary resuscitation, revealed massive pericardial effusion. It indicated the patient's cardiac arrest was pulseless electrical activity (PEA) due to cardiac tamponade. After pericardiocentesis, a perfusion rhythm was restored with palpable distal pulse. He successfully underwent a prosthetic graft replacement of the ascending aorta and was discharged after physical rehabilitation.

From agonal to output: An ECG history of a successful pre-hospital thoracotomy

This case report describes the first reported successful UK pre-hospital thoracotomy performed outside the London HEMS system. Continuous ECG monitoring during the procedure has allowed presentation of sequential ECGs recorded during the procedure.

A case of traumatic cardiac tamponade showing sudden spontaneous disappearance of the pericardial fluid

Traumatic cardiac tamponade must be treated by pericardial drainage as soon as possible. We recently encountered a rare case of traumatic cardiac tamponade in which the pericardial fluid disappeared spontaneously immediately before the planned drainage. This case is reported in this paper. The patient was a 22-year-old male who was transported to our hospital after he sustained injuries in a traffic accident. The patient was diagnosed to have a facial bone fracture, bilateral lung contusions, myocardial contusion (suspected), injury to the spinal cord at the L3-L4 level, injury to the left kidney and pelvic fracture. After TAE was performed to deal with the bleeding from the injured pelvis, the patient was immediately hospitalized. About 6 hours after the injury, pericardial fluid accumulation began to be noted, and about 18 hours after the injury, the patient went into shock, responding poorly to fluid resuscitation and treatment with pressor agents. At this time, a diagnosis of cardiac tamponade was made and emergency operation was arranged for. However, just before this could be executed, the patient's blood pressure showed a sharp rise, accompanied by disappearance of the pericardial fluid. He continued to show steady improvement and could eventually be discharged from the hospital.

Sensitivity and specificity of echocardiographic evidence of tamponade: implications for ventricular interdependence and pulsus paradoxus

The reported sensitivity of the echocardiographic finding of right atrial collapse for the diagnosis of tamponade ranges from 50% to100%; specificities have ranged from 33% to 100%. Its sensitivity in identifying right ventricular collapse ranges from 48% to 100% whereas the specificity ranges from 72% to 100%. Collapse of either the right atrium or right ventricle is not reliable except in cases where the risk of tamponade is high, consistent with Bayes' theorem. If the patient has hypotension, tachycardia, dyspnea, increased venous pressure, and a pericardial effusion, the diagnosis of tamponade will likely be sustained. To explain pulsus paradoxus, most echocardiographic reports have invoked Dornhorst's theory that inspiratory filling of the right ventricle actively collapses the left ventricle by successfully competing for a fixed total pericardial space ("ventricular interdependence"). However, the pericardial space is not fixed in tamponade but increases with inspiration, and the right heart is much more likely to collapse than the left, given their relative thickness. Pulsus paradoxus depends on the inspiratory surge to the right heart, exaggerated by the small stroke volume of both ventricles induced by tamponade, and vascular coupling between the pulmonary and systemic beds, with a transit time of one to two heart beats.