Bradycardia during reversible haemorrhagic shock ‐ a forgotten observation?

Witnessed asystole during spinal anesthesia treated with atropine and ondansetron: a case report

“…[1][2][3]12 Atropine can reverse the bradycardia but may fail to prevent the drop in BP and syncope caused by the sudden withdrawal of sympathetic tone. 5,7,8,13,22 Santagostino reported two patients who arrested under spinal anesthesia despite the use of atropine (0.7 mg and 1.0 mg). 12 He specifically commented on the efficacy of epinephrine and the relative inefficacy of atropine.…”

“…However, after a critical reduction of central volume, a sudden decompensatory phase characterized by bradycardia and profound sympathetic withdrawal can occur. 13 Thus, some hypovolemic patients may present with bradycardia, and further decreased preload can precipitate classic syncope or asystole. [4][5][6][7][8]14 The decrease in preload caused by spinal anesthesia may initiate vagally-mediated cardiodepressor reflexes such as the BJR with resulting bradycardia and sympathoinhibition.…”

Cardiovascular Monitoring and Substitution of the Blood Volume During Liver Transplantation

“…In textbook descriptions of hypovolaemic shock it is stated often that tachycardia is the arterial baroreceptor response to a low blood pressure (Secher & Bie, 1985). Yet the common, both experimental and clinical finding is that the HR response to central hypovolaemia encompasses three stages (Secher et al, 1992) (Fig.…”

Initial bradycardia in hypotensive (hemorrhagic) patients in a prehospital setting – does it have a prognostic value?

“…Traditional teaching associates increasing tachycardia with progressive hypovolemic shock and a decrease in heart rate as indicator of irreversible shock (terminal responsive) (1). Recent works support such a biphasic ("form M") pattern in response to hemorrhaging suggesting that the bradycardic response is reversible and not terminal, (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13).…”

“…Recent works support such a biphasic ("form M") pattern in response to hemorrhaging suggesting that the bradycardic response is reversible and not terminal, (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). The inability of the heart to respond to the shock with tachycardia has been described as relative bradycardia (2,15), paradoxical bradycardia (11) or the absence of tachycardia (1,12). Some clinical studies (15,16) and animal studies (6,23) have shown that the presence of relative bradycardia in hypotension (hemorrhaging) is associated with a better prognosis than the presence of tachycardia.…”