Cardiovascular Effects of Intrathecal Hyperbaric Prilocaine or Bupivacaine in Surgery Under Spinal Anesthesia

Spinal anesthesia remains a mainstay in lower limbs- as in day-case surgeries as well. It consists in injecting a local anesthetic drug into the intrathecal space of a patient's spinal canal. To achieve a suitable sensory and motor block for elective or emergent surgery, the anesthetist must adapt his choice of local anesthetic to the surgery's requirements and the patient's comorbidities, too. Spinal anesthesia is often associated with adverse cardiovascular events, notably hypotension which is a major concern in current anesthetic practice, especially in specific patient populations. Spinal induced hypotension is reported to be commonly related to the sympathetic block level and may be linked to perioperative cardiac and renal complications. Several mechanisms might play a role in the incidence of perioperative hypotension after spinal puncture. A decrease in peripheric systemic vascular resistance from arterial vasodilatation, a reduction of cardiac output due to a decrease in preload from a redistribution of venous blood into lower limbs or even an occurrence or increment of cardiac dysfunction, might compound proper blood flow towards noble organs such as brain, heart and kidneys. Spinal induced hypotension may also be related to a direct reduction of cardiac contractibility by the local anesthetic injection. Compensating mechanisms might be inhibited depending on the level of sympathetic blockade, usually related to the dose of the local anesthetic. Former studies found that intrinsic left ventricular depression might occur during spinal anesthesia as left ventricular volumes per se remain stable. One noticed that diastolic and systolic function (i.e., ventricular outflow tract velocity) decreased significantly after intrathecal levobupivacaine plus fentanyl injection based on transthoracic ultrasound assessment. Other authors use Pro-Brain Natriuretic Peptide to assess myocardial stress induced by surgery and anesthetic management. Other serum markers such