Intra‐operative bradycardia in a patient with Alzheimer's disease treated with two cholinesterase inhibitors
Bibliographic record
Abstract
Centrally acting cholinesterase inhibitors (ChEIs) are used to improve symptoms in patients with Alzheimer's disease. However, ChEIs may be associated with significant complications related to anaesthesia, and previous reports have documented prolonged paralysis when suxamethonium was administered to patients taking ChEIs [1, 2]. We report a case of severe peri-operative bradycardia in a woman taking two ChEIs. A 69-year-old woman was admitted for anterior colporrhaphy. She had been diagnosed with Alzheimer's disease 6 months earlier, and ChEI therapy had been initiated with rivastigmin. Because of neurologic improvement, an additional ChEI (galantamine) was commenced 2 weeks prior to the scheduled surgery. She was taking no other medications. There was no history of coronary artery disease, congestive heart failure, dyspnoea, syncope or arrhythmia. A pre-operative ECG showed sinus bradycardia at a rate of 55 beats.min−1. On the day of surgery, continuous ECG in the operating room showed sinus bradycardia at a rate of 58 beats.min−1 and a blood pressure of 130/70 mmHg. After pre-oxygenation, general anaesthesia was induced with midazolam 1 mg, fentanyl 50 μg, and propofol 130 mg. Tracheal intubation was facilitated with rocuronium 40 mg. Anaesthesia was maintained with nitrous oxide in oxygen with sevoflurane (end-tidal concentration 1–2%). After induction, the patient remained in sinus rhythm, but her heart rate decreased abruptly to 35 beats.min−1. Atropine was prepared but not given as the patient's systolic blood pressure remained above 90 mmHg. After 5 min, the heart rate increased to 45 beats.min−1, where it remained for the duration of the surgery. Neuromuscular blockade was reversed with neostigmine and glycopyrrolate and no change in heart rate was seen. Emergence from anaesthesia was uneventful, the trachea was extubated, and the ECG in the recovery room showed sinus bradycardia at a rate of 50 beats.min−1. The patient did not demonstrate postoperative lacrimation, excess salivation, diarrhoea or muscle fasciculations. There is no evidence to support the concurrent usage of two ChEIs [3]. Bradycardia in awake patients is rare with ChEIs [4], but has been previously reported [5]. Treatment with two ChEIs may have contributed to this patient's baseline sinus bradycardia. The heart rate decreased further after induction of anaesthesia, which is most likely explained by the loss of sympathetic tone after induction of general anaesthesia leaving the patient with the overwhelming cholinergic effects of the two ChEIs. Both propofol [6] and fentanyl [7] decrease sympathetic activity and could have potentially been the mechanism of the bradycardia. However, the dose of fentanyl was small and unlikely to have been the main contributing factor. Over time, the heart rate did increase slightly, suggesting recovery of the sympathetic tone, either from surgical stress or decreased sympatho-inhibition from declining plasma levels of propofol (although the heart rate still remained lower than baseline, probably because of the exaggerated cholinergic tone in this patient). We did not treat the bradycardia as the patient was haemodynamically stable. We did not observe any other stigmata of cholinergic toxicity. Although there is no definitive evidence of a causal relationship between the two ChEIs and the bradycardia, the associations presented in this case are compelling. It is possible that, as the prevalence of Alzheimer's disease rises and the use of ChEIs increases, so too might the frequency of related anaesthetic complications. Clinicians should be aware of possible heart rate changes in patients taking one or more cholinesterase inhibitors.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".