Case Report:
A 17-year-old male with a background of asthma took approximately 100g
of Yew Tree seeds at around 22:30 one evening in an attempt to end his
life. Assessment at the scene revealed bradycardia at 40 beats/minute,
hypotension at around 60/30 mmHg and hypothermia. His Glasgow Coma Score
(GCS) was 15/15. He was treated with IV Hartmann’s and 15L oxygen and
brought to the nearby district general hospital where he was admitted at
03:08am.
On arrival to the Emergency Department his ECG showed a ventricular
rhythm with a prolonged QT (QT 670ms / QTc 414ms) (Figure 1), so
external pacing pads were applied in preparation. His initial venous
blood gas showed a pH of 7.19 with a HCO3- of 24.8, BE of -4.8 and
lactate of 3.5 (other values largely normal) (Table 1).
Initial peripheral infusions were started: magnesium 1g, sodium
bicarbonate 1.26% at 83.3ml/hr, and Dobutamine 250mg in 500ml 5%
dextrose at 20ml/hr. Dobutamine was chosen over adrenaline due to
recommendations from Toxbase that adrenaline can worsen hypotension,
possibly due to beta agonist effects (6). Dobutamine was rapidly
titrated up to 30ml/hr but his bradycardia worsened to 20 beats/min and
his GCS dropped. External pacing was commenced and restored circulation.
Electrical capture was first obtained at 80mA, but this needed to be
titrated up to 120mA to sustain mechanical capture.
Once central venous access was established, Isoprenaline 2mg in 500mls
5% glucose was started at 30mls/hr. This was increased over the next 5
minutes to 98ml/hr to allow for cessation of external pacing.
Recommendations from Toxbase to aim for a pH of 7.5-7.55 (6) were noted,
and three boluses of 8.4% sodium bicarbonate were given which resulted
in a pH of 7.53 at 04:30, 82 minutes since first admission to hospital
(Table 1).
On advice from UK NPIS, ECMO was contacted for consideration of
transfer, but it was deemed to be too early at this stage of his
treatment. The on-call cardiologist successfully inserted a right
ventricular temporary pacing wire allowing Isoprenaline to be switched
off, showing an underlying rhythm of asystole. Pacing capture was
obtained at 0.5mA and the rate set to 80 beats/minute, giving a blood
pressure of 100/48 mmHg.
The patient was admitted to the Intensive Care Unit where he received a
Covid-19 throat swab which triggered an episode of emesis, in which he
regurgitated a mixture of whole and semi-digested seeds. Over the next
12 hours he was treated with further sodium bicarbonate, potassium,
magnesium and insulin therapy. Dobutamine was switched to an adrenaline
infusion which was quickly titrated down and stopped. The threshold for
his internal pacing wire increased to 1mA but held at that point. A
bedside echocardiogram showed no obvious abnormalities besides bilateral
pleural effusions.
28 hours after admission he switched into an unpaced broad complex
1st degree block rhythm with a QTc of 525ms. On day
three his pacing wire was removed. He was discharged home on day six
after seeing psychiatry, with further psychiatry follow-up and an
outpatient echocardiogram arranged.