Here is a video I produced for Adult Retrieval Victoria on Hamilton’s proprietary intelligent ventilation mode, ASV, using the Hamilton T1 Ventilator, but it’s applicable to our Hamilton C1.
Please do not distribute, as these videos are AV property.
ASV takes into account the patient’s respiratory mechanics, which are measured breath-by-breath by the proximal flow sensor. ASV ensures optimal ventilation for each patient during passive ventilation but also has automatic adjustment in spontaneously breathing and weaning patients.
In passive patients, ASV is a volume-targeted pressure controlled mode with automatic adjustment of inspiratory pressure, respiratory rate, and inspiratory/expiratory time ratio. Maximum tidal volume is controlled by setting a maximum inspiratory pressure. Expiratory time is determined according to the expiratory time constant in order to prevent dynamic hyperinflation.
Watch the following video, together with the Initial Setup (Page 2) & Troubleshooting Guides below:
Cliff Read recently put out a great post on this issue.
The take home points:
Perform when refractory shock with evidence of tamponade physiology on ECHO:
A large effusion with a ‘little invisible man using the RV as a trampoline”
Remove only small volumes of blood at a time (e.g. 30mls), aiming for a SBP of 90 mmHg.
The danger is overshooting the BP, resulting in hypertension and extension of the dissection which can be fatal.
Avoid intubation if possible until a surgeon is ready to cut – positive pressures lead to worsening tamponade physiology (although mitigated by pericardiocentesis).
Other options include intubation under local anaesthesia, allow the patient to breathe spontaneously through the tube, or preloading with fluid, using cautious doses of induction agent, and ventilating with low pressures & zero PEEP.
CPR is futile in arrested patient.
CPR leads to lower MAP and diastolic pressures, therefore worsening coronary perfusion. Only relief of tamponade will provide a chance of recovery.
Patients requiring transport should be accompanied by a clinician able to perform pericardiocentesis in the event of deterioration en route.
There are several approaches – subxiphoid, left parasternal, apical. Go where the most blood is.
If they arrest To intubate or not to intubate?
CPR or no CPR?
How to transfer – physician escort or just send in an ambulance on lights and sirens?
An in-depth look at the management of hyponatraemia, with special attention to a new concept called the “dDAVP clamp.”
– only treat hyponatraemia if symptoms are severe – coma, seizures or severe delirium
– use 3% saline 100ml, up to three doses
– consider giving dDAVP to prevent a rapid climb in the serum sodium
– aim to correct the serum sodium by only 3-6mmol/L in the first 24 hours