Sedation protocol
In our center all AF ablation procedures are usually performed under
conscious sedation; GA is not routinely used. During the first part of
the year, AF ablation procedures were performed using propofol, which
was administered and monitored by an anesthesiologist in the operating
room (group 1). Induction of sedation was performed with a bolus of 2 ml
of 1% propofol followed by an infusion starting at 1 mg/Kg/h and then
titrated to the clinical response.
After the unexpected COVID-19 pandemic arrival, due to organizational
challenges and given the shortage of available anesthesiologists,
sedation was performed by the electrophysiology (EP) team (consisting of
two operating electrophysiologists for each procedure, at least two
dedicated nurses and a radiology technician) using dexmedetomidine
(group 2) without anesthesiologist supervision, according to a shared
protocol approved in advance. The EP medical and nursing staff were
trained and certified in advanced life support. An on-call
anesthesiologist was available from within the hospital in case of
emergency.
In both groups, patient’s monitoring started in the EP laboratory
waiting room: non-invasive blood pressure, heart rate and rhythm and
oxygen saturation were continuously recorded. End-tidal carbon dioxide
(etCO2) monitoring was used to detect early respiratory
dysfunction. In the EP laboratory, a 12-lead electrocardiogram (ECG) was
continuously recorded for every patient; respiratory rate was also
assessed. Continuous infusion of dexmedetomidine was started at a rate
of 0.7 mcg/Kg/h before venipuncture and titrated to clinical response
during the procedure (maximum dosage 1.4 mcg/Kg/h) in order to obtain
patient’s sedation with cessation of body movements. In case of adverse
events, dexmedetomidine infusion rate was reduced if deemed necessary.
Oxygen supplementation was administered by nasal cannulas at 2 l/min at
baseline in both groups.
At the beginning of the procedure every patient (either in the propofol
or in the dexmedetomidine group) received 1 mcg/Kg of midazolam as a
single bolus. Moreover, a 0.05 mg single bolus of fentanyl was
administered for analgesia prior to radiofrequency application on the
left pulmonary veins (PVs), and the bolus was repeated before starting
ablation on the right PVs. If the patient was in AF when entering the EP
laboratory, electrical cardioversion (EC) was performed at the beginning
of the procedure with an additional bolus of propofol 1 mg/Kg in both
groups. In case of EC, the starting infusion rate in group 1 was reduced
to 0.8 mg/Kg/h without any other bolus.
Vital signs were monitored throughout the procedure: peripheral oxygen
saturation, respiratory rate, heart rate and rhythm were monitored
continuously, while blood pressure was monitored with a brachial cuff at
3-minute intervals.
Adverse events such as oxygen desaturation (< 90%),
bradycardia (heart rate < 45 bpm) and hypotension (systolic
blood pressure < 90 mmHg) were recorded. In case of airway
compromise, the head tilt-chin lift maneuver was performed; in case of
desaturation oxygen delivery was increased and/or the nasal cannula was
changed to a facial mask with increased oxygen delivery capability
with/without insertion of an oropharyngeal airway; in case of
bradycardia, cardiac stimulation was performed via the catheters placed
in the heart or by atropine administration; in case of significant
hypotension, saline loading was performed with simultaneous check for
mechanical complications by means of intracardiac echocardiography
(ICE), routinely used during AF ablation procedures at our Institution.