Effects of Crystalloid Preloading (20 ml/kg) on Hemodynamics in Relation to Postural Changes in Patients Undergoing Neurosurgical Procedures in Sitting Position

Effect of Preanesthetic Fluid Loading on Postinduction Hypotension and Advanced Cardiac Parameters in Patients with Chronic Compressive Cervical Myelopathy: A Randomized Controlled Trial

Purpose  Hypotension during the early intraoperative phase is common and can lead to adverse perioperative outcomes. Fluid preloading is one of the methods to limit its occurrence. Patients with chronic compressive cervical myelopathy may have autonomic dysfunction, which can aggravate hemodynamic alterations during anesthesia. This study compared the occurrence of postinduction hypotension and changes in cardiac dynamic indices in patients with and without crystalloid preloading undergoing decompressive cervical spine surgery.

Methods  This randomized controlled trial was conducted over 15 months after obtaining patient consent, approval of the institute ethics committee, and trial registration. We compared preanesthetic fluid loading with Ringer's lactate (20 mL/kg over 30 minutes) with no preloading (2 mL/kg/h maintenance) in 60 consecutive patients undergoing cervical spine surgery. The ANSiscope was used to determine baseline cardiac autonomic function. Noninvasive cardiac output monitor was used to assess changes in heart rate, mean arterial pressure, cardiac index (CI), stroke volume variation (SVV), and total peripheral resistance index during study intervention, anesthetic induction, tracheal intubation, and change in position from supine to prone.

Results  The incidences of postinduction hypotension were 26.7% (8/30) and 86.7% (26/30) and the median doses of mephentermine used were 0 and 6 mg, respectively, in patients with and without fluid preloading (both p  < 0.001). Preloading resulted in improvement in CI, reduction in SVV, and lesser vasopressor use.

Conclusion  Preloading reduced the occurrence of postinduction hypotension and vasopressor use, improved CI, and reduced SVV during the early intraoperative period.

Registration number of Clinical Trial  The trial was registered with Clinical Trial Registry of India (CTRI/2018/07/014970 on 19/07/2018).

Air-embolism in the semi-sitting position for craniotomy: A narrative review with emphasis on a single centers experience

Albeit the semi-sitting position in neurosurgery has been in use for several decades, its application remains controversial in the neurosurgical and neuro-anaesthesia communities. The imminent and most feared risk of the sitting position is air entry into the vascular system due to the negative intravascular pressure leading to potentially life-threatening air embolism with its consequences. Recent advents in neurosurgical (improvement of the operating microscope, employment of intra-operative neurophysiological monitoring) and neuro-anaesthesia care (new anaesthetics, advanced monitoring modalities) have significantly impacted the approach to these surgeries. Vigilant intra-operative observation by an experienced team and peri-operative patient management guided by institutional protocols improves the safety profile of these surgeries. This review outlines the workflow and protocols used in our institution for all cases of semi-sitting position for skull base neurosurgery.

Anesthetic Management of Patients Undergoing Open Suboccipital Surgery

The posterior cranial fossa with its complex anatomy houses key pathways regulating consciousness, autonomic functions, motor and sensory pathways, and cerebellar centers regulating balance and gait. The most common posterior fossa pathologies for which neurosurgical intervention may be necessary include cerebellopontine angle tumors, aneurysms, and metastatic lesions. The posterior cranial fossa can be accessed from variations of the supine, lateral, park-bench, prone, and sitting positions. Notable complications from positioning include venous air embolism, paradoxic air embolism, tension pneumocephalus, nerve injuries, quadriplegia, and macroglossia. An interdisciplinary approach with careful planning, discussion, and clinical management contributes to improved outcomes and reduced complications.