Difficult Weaning Off Cardiopulmonary Bypass (CPB)

As I mentioned in the presentation, the checklist is a way to have everyone sharing the same mental model, everyone should aim towards the same goal. The anesthesia, surgeon, and perfusionist checklist are the same: one checklist should be used for the whole team. The whole team should be focused during the execution of the checklist, that way, everyone is aware of the situation of the patient's condition and of the team. Unfortunately, there is only research done by anesthesiologists.

I understand what you try to say, that if the team is well enough trained, there is no need for a checklist. But is it the same as with the preoperative safty checklist: it really helps to make sure every aspect of the weaning process is executed, and the risl for errors is made as low as possible. It also helps to introduce new members to the team. Standardization is one of the key factors in the success of quality improvement.

There is no real answer to that. There is actually no research done and the guidelines literally so the same. No evidence for any strategy.

Not sure if this is a question about the weaning checklist, but this is an item that can certainly be added. Teams should feel the most comfortable with the custom version of a checklist. If it is an item that is often forgotten: add it; if it is something that feels redundant or making the checklist too long: leave it out.

As part of a multimodal strategy to assess volume status, I use CVP as a routine. I think the serial and continuous analysis of CVP is valid, especially in patients with preserved EF. In those with low EF, it gets more complicated. In these cases, I believe that TEE is fundamental. I indicate a good paper that makes an excellent review of CVP for volume analysis: Christian Schmidt, Astrid Ellen Berggreen, Matthias Heringlake, Perioperative hemodynamic monitoring: Still a place for cardiac filling pressures? Best Practice & Research Clinical Anesthesiology, Volume 33, Issue 2, 2019, Pages 155-163, ISSN 1521-6896, https://doi.org/10.1016/j.bpa.2019.04.004.

The most cost-effective catheter-based monitor with established evidence for weaning off CPB remains the PAC. The use of TEE is fundamental in several scenarios in cardiac anesthesia. Despite having a high initial cost and subject to repairs over time, TEE when purchased through reseller companies that offers insurance can be a solution for costs associated with probe repairs.

There is a lack in the literature in terms of conclusive RCT’s in this regard. Despite promising trials in progress, this is a question that still needs research to generate conclusions. The greatest evidence is found in the low values of cerebral oximetry in the preoperative period and poor outcomes, including cognitive.

For sure. This is one of the main applications of PAC in cardiac anesthesia. Reference paper: Curr Opin Crit Care 2018, 24: 204–208.

I mainly use TEE. When the LV end-diastolic diameter is normal and the LV end-systolic diameter is low, there is vasoplegia. When both are low, there is probably hypovolemia. In the absence of TEE, most catheter-based monitors calculate systemic vascular resistance.

A single dose of IV MB (2 mg/kg, 20-min infusion time) has been used as rescue treatment in vasoplegic syndrome afetr prolonged CBP. There is a randomized controlled trial in which 56 patients with vasoplegia received IV MB (1.5 mg/kg over 1-h) or placebo. There were no deaths in the MB group and six deaths (21.4%) in the placebo group. Methylene blue reversed vasoplegia in about 2 h, while in those treated with vasopressors (28.6%) only, vasoplegia persisted for more than 48 h. Leyh et al. [7] reported on the use of MB (2 mg/kg over 20 min) in 54 patients with norepinephrine-refractory vasoplegia with similar results.

No bolus. Start infusion with 0.05 mcg/Kg/min and increase the dose to 0.2 mcg/kg/min. Be aware that MAP is not less then 65. If needed, you can add a low dose of Norephinephrine.

Levosimendan is useful in difficult weaning from CBP, but needs "time to work" and if you have an unespected difficult weaning it is not the first line therapy. It is very useful in planned difficult weaning from CBP as in high risk patients. In this setting perioperative Levosimendan infusion is recommended.

I consider use of Levosimendan in planned difficult weaning from CBP as in patients with risk factors in particular with CAD. I suggest to start with perioperative infusion with NO BOLUS; only continuos infusion 0.05 mcg/kg/min to 0.2 mcg/kg/min according to hemodynamic stability.

Although the scientific evidence is low the calcium administration is very common in the clinical practice during the weaning from the CPB. A recent survey (JCVA 2020) showed that the 78% of centers use calcium to correct hypocalcemia and in to improve the hemodynamic parameters. It briefly improves cardiac index and blood pressure in patients undergoing cardiac surgery. Possible side effects are: impaired response to beta-adrenomimetics, pancreatic injury, internal thoracic artery graft spasm, and the “stone heart” phenomenon. We have to wait the results of the ICARUS trail to have a more clear picture

Methylene blue is a drug commonly used to treat vasoplegia. It is contraindicated in patients at high risk of serotonergic syndrome (pre-operative use of serotonin norepinephrine reuptake inhibitors, selective serotonin re-uptake inhibitors, clomipramine) or glucose 6-phosphate dehydrogenase deficiency. When the risk is low then a slow bolus of 2 mg/kg of methylene blue followed by a continuous infusion of 0.25 mg/kg/h for 6 hours is indicated

For the postcardiotomy shock due to RV failure, the VA ECMO is the simplest and quickest solution to avoid a persistent LCOS. Clinical data supporting the use of VA-ECMO in the setting of acute RV failure are limited to case series and the mortality is as high as 60%. In this setting, the ECMO is usually central and the chest remained opened (only skin closure). Open chest may be in an option to gain time in the refractory RV dysfunction with or without ECMO.

Although the level of evidence is low a temporary ECMO-facilitated RV support is mandatory to gain time. It is important to avoid any delay.

CABG first.

Stone heart or ischemic myocardial contracture that I have faced rarely and in patients with high dosage of inotropes/vasopressors. Even the calcium may trigger this phenomenon. It seems secondary to intracellular calcium overload after ischemic episode “calcium paradox”.

The diastolic dysfunction is a heterogeneous disease that requires tailored management. AV interval optimization is useful to prolong the diastolic time and filling time.

Useful to reduce the increased in afterload due to a VA-ECMO. In fact in the event of LV dysfunction, the pressure volume loops show high LVEDP, low SV, and EF. As ECMO flow increases, the primary hemodynamic effect is the increase in afterload. If peripheral resentences and LV contractility are fixed, the only way for the LV to overcome the increased afterload is via the Starling mechanism. An echo showing a persistently closed aortic valve during ECMO means high LVEDP, PCWP and pending pulmonary edema. This ECMO primary hemodynamic effect can be modulate by the decreasing systemic resistances or increasing contractility. Both can be achieved with IABP.

Systolic dysfunction is diagnosed using TEE in the presence of reduced contractility, low ejection fraction and RWMA despite adequate preload assessment (Frank-Starling law), heart rate and rhythm and low doses of inotropic drugs.

It could be an option but another option could be to use specific cover of TEE probe followed by routine clean and sterilization of the probe.

LASP= SBP - 4(VMR)2
SBP (Systolic Blood pressure), VMR (peak velocity of mitral valve regurgitation jet measured by CW Doppler in any ME view of the mitral valve). In case of AS or LVOT obstruction this measured is not reliable.

Deceleration time
E/A in case of DDD pacing
Vp M-mode color Doppler