We are now going to review the diagnosis and management of pericardial collections and tamponade

Transcription

1 We are now going to review the diagnosis and management of pericardial collections and tamponade FEEL COURSE PAGE 1

2 Paying particular attention to the difference between a collection and cardiac tamponade Following with a description of ultrasound guided pericardiocentesis And a video demonstration FEEL COURSE PAGE 2

3 In cardiac arrest and the peri arrest scenario echo can be used to diagnose the presence or absence of a pericardial collection and also can help confirm whether or not any collection is contributing to the low cardiac output state i.e. clinical tamponade Echocardiogrpahy can also be used to guide attempted drainage of any collection - safely FEEL COURSE PAGE 3

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5 The lecturer describes the structure of the pericardium, emphasising that it is formed of two layers, between which exists a small volume of pericardial fluid whose purpose is primarily to allow easy movement of the heart with each beat. The normal volume of pericardial fluid is described, and the normal intra-pericardial pressures. The superior and inferior attachments of the pericardium are described Key point There are 2 layers to the pericardium between which exists fluid, and the limits of a pericardial collection are defined by the limits of the pericardial attachments FEEL COURSE PAGE 5

6 Normal pressure is Physiological properties accommodate only small increase in intra pericardial volume then exponential rise in pressure Freeman & LeWinter 1984: permission required FEEL COURSE PAGE 6

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8 This slide demonstrates the wide variety of pathologies that may cause an abnormally large amount of fluid in the pericardial space. Highlighted are those that most commonly are associated with acute cardiovascular collapse e.g. Coxsackie Parvovirus B19 HIV Idiopathic Pericarditis (Usually viral) Infectious pericarditis: Viral TB Bacterial Acute MI Rupture Dressler s Uraemia Malignancy primary and secondary Post radiotherapy Trauma Aortic Dissection (Type A) Iatrogenic: cardiac surgery Haematoma Dressler s Iatrogenic: cardiology procedures AF ablation Pacing PCI Devices Rarities FEEL COURSE PAGE 8

9 Key Message: in the PLAX (shown) the reflection of the pericardium at the post-av groove is seen, representing the limit of pericardial collections. Meanwhile the pleural space (and pleural fluid) continues under the LA, posterior to the descending aorta. FEEL COURSE PAGE 9

10 By contrast, a movie is shown demonstrating the anatomy of a pericardial collection in the PLAX view. A very small pericardial collection is seen and a large pleural collection the two layers of the pericardium are clearly seen. FEEL COURSE PAGE 10

11 A movie of a pericardial collection in the apical 4chamber view. The 4 cardiac chambers and 2 atrio-ventricular valves are demonstrated, together with an almost circumferential pericardial collection around the RA, RV and LV. The two pericardial layers are clearly demonstrated FEEL COURSE PAGE 11

12 A movie of a pericardial collection in the subcostal view. The 4 cardiac chambers and 2 atrio-ventricular valves are demonstrated, together with pericardial collection (arrowed) FEEL COURSE PAGE 12

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14 The definition of tamponade demonstration of collection in the presence of significantly adverse haemodynamics FEEL COURSE PAGE 14

15 This graph shows that the rate of accumulation is more important than the volume of collection. In response to long-standing stress the pericardium dilates, shifting the pericardial pressure-volume relationship to the right On the x axis is the volume of fluid removed (ml) vs the pericardial pressure (y axis). Chronic collection is shown in blue and acute is shown in red. In the chronic collection (blue) the pericardial pressure is 20mmHg, falling to 5 mmhg with removal of 900ml of fluid. By contrast, in the acute collection, the pericardial pressure is much higher (48mmHg) and contains a smaller volume (220ml total) here drainage of only a small volume (50ml) results in a significant reduction in pericardial pressure falling to 5mmHg after removal of only 160ml fluid. Key points The pressure (and thus haemodynamic consequences) of a pericardial collection depends upon its rate of collection a small but rapidly accumulating collection may therefore have catastrophic haemodynamic effects, whereas a chronically accumulating collection may be of very large volume with relatively little/no haemodynamic impact. FEEL COURSE PAGE 15

16 Suggestion not to dwell to long (may be difficult conceptually for students) FEEL COURSE PAGE 16

17 Claude Beck JAMA st American Professor of cardiac surgery and 1 st man to perform defibillation. JAMA 1935: Tamponade in surgical patients: Becks Triad: Low blood pressure, High JVP, Muffled heart sounds The classical clinical features of tamponade are described (Beck s triad) these are raised JVP, muffled HS and pulsus paradoxus. Other features low C.O. State: Vasoconstriction / poor cap refill, Oliguria, Metabolic acidosis These features may be absent & difficult to ascertain in the peri-arrest situation If on echocardiography a collection is noted, associated additional features may be seen in tamponade FEEL COURSE PAGE 17

18 Various echocardiographic features have been associated with the presence of tamponade the more commonly seen ones are shown in this slide: Those which occur in all parts of the respiratory cycle are listed on the left of the slide, and those that vary according to the phase of the cardiac cycle are shown to the right of the slide The majority of the features (particularly those that vary with respiration) are beyond the scope of peri-resuscitation echocardiograhpy, as they involve the use of more sophisticated echo modalities (i.e. Doppler), and interpretation of the features during inspiration (which may change on intubation and with positive pressure ventilation) therefore for FEEL, we will concentrate on those readily identifiable features that can be seen using 2D (and M-mode), and do not depend upon changes in respiration. FEEL COURSE PAGE 18

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21 Apical 4 chamber view in a patient with tamponade. The patient is tachycardic (note HR 101 in the bottom right of the picture) Second, there is an echo-free space around the RA, RV and appearing around the LV which is a pericardial collection. RV diastolic collapse: The normal movement of the RV free wall is inward during systole, and outward in diastole (with right heart filling). In tamponade, where the intrapericardial pressure exceeds that of the RV in diastole this will result in abnormal inward movement during this phase of the cardiac cycle. On the left of the slide is shown the same video in slow motion (apical 4 chamber view) slowed down in order to demonstrate the inward movement of the RV during diastole (RV diastolic collapse, arrowed) which is one of the echocardiographic features of tamponade. This may be more easily appreciated using M-mode (on the right of the slide): A miniature 2D (PLAX) is shown at the top of the figure for orientation and an ECG to demonstrate timing within the cardiac cycle. Inward movement of the RV free wall during diastole is arrowed. FEEL COURSE PAGE 21

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23 A short axis view of the same patient showing the right and left ventricles swinging in the echo-lucent space that is the pericardial collection. FEEL COURSE PAGE 22

24 Swinging heart The heart is not normally free to swing in the chest being restrained by its connections to the great arteries, pulmonary veins and cavae, as well as the lungs and diaphragm. Where a large collection is seen, the heart will appear to swing about its superior connections. In this 2D study long axis view, the heart is seen swinging in a large pericardial collection (echo free space around the heart) FEEL COURSE PAGE 23

25 Paying particular attention to the difference between a collection and cardiac tamponade Following with a description of ultrasound guided pericardiocentesis And a video demonstration FEEL COURSE PAGE 24

26 Fluid loading may have a transient benefit. Pericardiocentesis FEEL COURSE PAGE 25

27 The haemodynamic effects of tamponade can be reversed by pericardiocentesis as seen in this slide In the upper part of the slide is shown systolic blood pressure (mmhg) and the lower shows heart rate each plotted against time (x axis) Two interventions are performed (arrowed): first, the administration of volume resuscitation (16:18) and second, pericardiocentesis (16:38) Following volume resuscitation, there is a slight rise in blood pressure which is not sustained, and a progressive increase in heart rate. Following pericardial puncture, there is a sharp rise in SBP, and a resolution of the tachycardia The remaining slides will outline the procedure for safe pericardiocentesis FEEL COURSE PAGE 26

28 To mention (& for manual): FEEL /ALS consider non-traumatic tamponade. (Traumatic tamponade ATLS subject). Surgeon post-surgery, post trauma, loculated, recurrent FEEL COURSE PAGE 27

29 The equipment used will depend upon the clinical scenario, the available kit and the experience & preference of the operator. In certain circumstances, a full pericardiocentesis kit may be used (left of slide) but this is often not readily available in the peri-arrest situation (unless in certain specialist centres). FEEL COURSE PAGE 28

30 This diagram shows the two main approaches for drainage of a pericardial collection. During the diagnostic echo, the echo operator should (where the collection is not global and massive) note the best approach to drainage where the collection is deepest and closest to the chest wall - parasternal or subxiphoid FEEL COURSE PAGE 29

31 Not all collections can be drained easily On the left is a subcostal 4Ch view showing a circumferential collection but small, with very little separation between the pericardial layers carrying with it a high risk of RV puncture if drainage is attempted On the right is a subcostal view showing a large circumferential collection risk of RV puncture would be low for an experienced operator FEEL COURSE PAGE 30

32 This is a short video outlining the steps involved in pericardiocentesis ECG monitoring will usually be in place (and should be used if possible, as excessive new ventricular ectopy may signify direct myocardial irritation with the needle Then click to start video - (this is where you need to talk them through step by step the volume on the computer will be switched off) The patient s skin should be prepped and draped (as time allows) as shown. Insertion below xiphoid at 45 to the skin aiming for mid-left clavicle or left shoulder If blood/pericardial fluid returns, advance the catheter over needle, leaving the catheter in situ & aspirate rest of fluid (leave catheter in for additional aspiration if necessary) Then go on to say that if the Seldinger technique is used, the procedure is identical up to the point of needle insertion and obtaining fluid back at that stage, instead of withdrawing the needle, pass a flexible guidewire through needle into pericardial sac, then remove the needle leaving the guidewire in place, and pass a flexible catheter over the needle, remove the wire and aspirate. Some kits come complete with a 3-way tap and pericaridocentesis bag. FEEL COURSE PAGE 31

33 There are many potential complications of pericardiocentesis which are outlined on this slide (list them) they all involve puncturing/needle irritation of important structures, and may be reduced by the use of echocardiography guidance during the procedure. FEEL COURSE PAGE 32

34 Step 1 sheath the transducer. If no time, or not available, echo remote from the site of puncture (more challenging however) i.e. A4Ch view or PLAX view Step 2 Assess: optimal window, direction of puncture and distance to pericardium from the skin ideally directly adjacent to where you intend to puncture (regardless of whether subxiphoid or parasternal). (You can image remotely, however, here identification of the needle is more difficult) Step 3 Use echo to help confirm placement: (i)real-time: introduce the needle next to the transducer, and visualise it entering the pericardial space (this is shown in the video, A4Ch view). lying supine. Can be difficult periarrest in tachypnoeic, subject esp if obese and (i)if using the Seldinger technique, often easy possible to see the guidewire in the collection FEEL COURSE PAGE 33

35 Step 4 once blood/fluid is drawn back, injection of a small amount of agitated saline can be useful to confirm correct placement in the pericardial space (as opposed to a cardiac chamber particularly where the collection is traumatic or very bloody). Here, the saline gives a smoky/bubbly appearance to the pericardial space, and persists. Where chamber puncture has occurred, no bubbles will be seen in the collection, and they will be cleared rapidly from the heart. Let bubbles lead the way. This is difficult esp if fat, supine and Kaussmal breathing with a small collection. FEEL COURSE PAGE 34

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38 In cardiac arrest and the peri arrest scenario echo can be used to diagnose the presence or absence of a pericardial collection and also can help confirm whether or not any collection is contributing to the low cardiac output state i.e. clinical tamponade Echocardiogrpahy can also be used to guide attempted drainage of any collection - safely FEEL COURSE PAGE 37

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