Flow diversion of ruptured intracranial aneurysms: a single-center study with a standardized antithrombotic treatment protocol.

BACKGROUND: The use of antithrombotic medication following acute flow diversion for a ruptured intracranial aneurysm (IA) is challenging with no current guidelines. We investigated the incidence of treatment-related complications and patient outcomes after flow diversion for a ruptured IA before and after the implementation of a standardized antithrombotic medication protocol. METHODS: We conducted a single-center retrospective study including consecutive patients treated for acutely ruptured IAs with flow diversion during 2015-2023. We divided the patients into two groups: those treated before the implementation of the protocol (pre-protocol) and those treated after the implementation of the protocol (post-protocol). The primary outcomes were hemorrhagic and ischemic complications. A secondary outcome was clinical outcome using the modified Ranking Scale (mRS). RESULTS: Totally 39 patients with 40 ruptured IAs were treated with flow diversion (69% pre-protocol, 31% post-protocol). The patient mean age was 55 years, 62% were female, 63% of aneurysms were in the posterior circulation, 92% of aneurysms were non-saccular, and 44% were in poor grade on admission. Treatment differences included the use of glycoprotein IIb/IIIa inhibitors (pre-group 48% vs. post-group 100%), and the use of early dual antiplatelets (pre-group 44% vs. 92% post-group). The incidence of ischemic complications was 37% and 42% and the incidence of hemorrhagic complications was 30% and 33% in the pre- and post-groups, respectively, with no between-group differences. There were three (11%) aneurysm re-ruptures in the pre-group and none in the post-group. There were no differences in mortality or mRS 0-2 between the groups at 6 months. CONCLUSION: We found no major differences in the incidence of ischemic or hemorrhagic complications after the implementation of a standardized antithrombotic protocol for acute flow diversion for ruptured IAs. There is an urgent need for more evidence-based guidelines to optimize antithrombotic treatment after flow diversion in the setting of subarachnoid hemorrhage.

Venous air embolisms and sitting position in Helsinki pineal region surgery.

BACKGROUND: Nowadays, the sitting position has lost favor among neurosurgeons partly due to assumptions of increased complications, such as venous air embolisms (VAEs) and hemodynamic disturbances. The aim of our study is to describe the importance of some anesthetic considerations and the utility of antigravity trousers as well, together with a skillful neurosurgery and an imperative proper teamwork, in order to prevent the risk of severe VAE during pineal region surgery. We routinely use them for the variant of the sitting position we developed, the "praying position." METHODS: A retrospective review of 51 pineal lesions operated on in the "praying position" using antigravity trousers was carried out. In the "praying position" the legs of the patient are kept parallel to the floor. Hence, antigravity trousers are used to generate an adequate cardiac preload. RESULTS: VAE associated to persistent hemodinamic changes was nonexistent in our series. The rate of VAE was 35.3%. VAEs were diagnosed mainly by monitoring of the end-tidal CO2 (83.33%). A venous system lesion was the cause in most of the cases. When VAE was suspected, an inmediate reaction based on a good teamwork was imperative. No cervical spine cord injury nor peripheral nerve damage were reported. The average microsurgical time was 48 ± 33 min. CONCLUSIONS: The risks of severe VAE during pineal region surgery in the "praying-sitting position" may be effectively prevented by some essential anesthetic considerations and the use of antigravity trousers together with a skillful neurosurgery, and an imperative proper teamwork.

Praying Sitting Position for Pineal Region Surgery: An Efficient Variant of a Classic Position in Neurosurgery.

BACKGROUND: The sitting position has lost favor among neurosurgeons partly owing to assumptions of increased complications, such as venous air embolisms and hemodynamic disturbances. Moreover, the surgeon must assume a tiring posture. We describe our protocol for the "praying position" for pineal region surgery; this variant may reduce some of the risks of the sitting position, while providing a more ergonomic surgical position. METHODS: A retrospective review of 56 pineal lesions operated on using the praying position between January 2008 and October 2015 was performed. The praying position is a steeper sitting position with the upper torso and the head bent forward and downward. The patient's head is tilted about 30° making the tentorium almost horizontal, thus providing a good viewing angle. G-suit trousers or elastic bandages around the lower extremities are always used. RESULTS: Complete lesion removal was achieved in 52 cases; subtotal removal was achieved in 4. Venous air embolism associated with persistent hemodynamic changes was nonexistent in this series. When venous air embolism was suspected, an immediate reaction based on good teamwork was imperative. No cervical spine cord injury or peripheral nerve damage was reported. The microsurgical time was <45 minutes in most of the cases. Postoperative pneumocephalus was detected in all patients, but no case required surgical treatment. CONCLUSIONS: A protocolized praying position that includes proper teamwork management may provide a simple, fast, and safe approach for proper placement of the patient for pineal region surgery.

Prone Versus Sitting Position in Neurosurgery-Differences in Patients' Hemodynamic Management.

OBJECTIVE: Neurosurgery in general anesthesia exposes patients to hemodynamic alterations in both the prone and the sitting position. We aimed to evaluate the hemodynamic profile during stroke volume-directed fluid administration in patients undergoing neurosurgery either in the sitting or the prone position. METHODS: In 2 separate prospective trials, 30 patients in prone and 28 patients in sitting position were randomly assigned to receive either Ringer acetate (RAC) or hydroxyethyl starch (HES; 130 kDa/0.4) for optimization of stroke volume. After combining data from these 2 trials, 2-way analysis of variance was performed to compare patients' hemodynamic profile between the 2 positions and to evaluate differences between RAC and HES consumption. RESULTS: To achieve comparable hemodynamics during surgery, a higher mean cumulative dose of RAC than HES was needed (679 mL ± 390 vs. 455 mL ± 253; P < 0.05). When fluid consumption was adjusted with weight, statistical difference was lost. Fluid administration did not differ between the prone and sitting position. Mean arterial pressure was lower and cardiac index and stroke volume index were higher over time in patients in the sitting position. CONCLUSIONS: The sitting position does not require excess fluid treatment compared with the prone position. HES is slightly more effective than RAC in achieving comparable hemodynamics, but the difference might be explained by patient weight. With goal-directed fluid administration and moderate use of vasoactive drugs, it is possible to achieve stable hemodynamics in both positions.

Stroke volume-directed administration of hydroxyethyl starch (HES 130/0.4) and Ringer's acetate in prone position during neurosurgery: a randomized controlled trial.

PURPOSE: General anesthesia in the prone position is associated with hypotension. We studied stroke volume (SV)-directed administration of hydroxyethyl starch (HES 130 kDa/0.4) and Ringer's acetate (RAC) in neurosurgical patients operated on in a prone position to determine the volumes required for stable hemodynamics and possible coagulatory effects. METHODS: Thirty elective neurosurgical patients received either HES (n = 15) or RAC (n = 15). Before positioning, SV measured by arterial pressure waveform analysis was maximized by fluid boluses until SV did not increase more than 10 %. SV was maintained by repeated administration of fluid. RAC 3 ml/kg/h was infused in both groups. Thromboelastometry assessed coagulation. Mann­Whitney U test, Wilcoxon signed-rank test, ANOVA on ranks, and a linear mixed model were applied. RESULTS: Comparable hemodynamics were achieved with the mean cumulative (SD) boluses of HES or RAC 240 (51) or 267 (62) ml (P = 0.207) before positioning, 340 (124) or 453 (160) ml (P = 0.039) 30 min after positioning, and 440 (229) or 653 (368) ml at the end of surgery (P = 0.067). The mean dose of basal RAC infusion was 813 (235) and 868 (354) ml (P = 0.620) in the HES and RAC group, respectively. Formation and maximum strength of the fibrin clot were decreased in the HES group. Intraoperative blood loss was comparable between groups (P = 0.861). CONCLUSION: The amount of RAC needed in the prone position was 25 % greater. The cumulative dose of 440 ml HES induced a slight disturbance in fibrin formation and clot strength. We suggest cautious administration of HES during neurosurgery.

Effect of the combination of mannitol and ringer acetate or hydroxyethyl starch on whole blood coagulation in vitro.

Mannitol is administered to decrease the intracranial pressure and to improve surgical conditions during craniotomy. Simultaneously a crystalloid infusion is always given and sometimes hydroxyethyl starch (HES) is indicated for intravascular volume replacement. As normal coagulation profile is required during craniotomy, we aimed at determining the effect of mannitol with or without HES or Ringer acetate on blood coagulation in this randomized cross-over in vitro study. Blood samples were withdrawn from 10 volunteers. From whole blood we prepared 10 vol.% and 20 vol.% dilutions of mannitol (15% Mannitol) alone, mannitol and Ringer acetate, and mannitol and HES 130/0.4 (Voluven) at a ratio of 1:1. Blood samples were analyzed by modified thromboelastometry. Coagulation parameters: clotting time, clot formation time, and maximum clot firmness (MCF), were registered. Clot formation time was prolonged in all dilutions compared with control (P<0.05). MCF decreased in all dilutions compared with control (P<0.05). MCF in 20 vol.% dilution of mannitol with HES was lower than MCF in the corresponding dilution with Ringer acetate (P<0.05). Fibrinogen-dependent MCF in 10 vol.% dilution of mannitol with HES was lower than MCF in the corresponding dilution with Ringer acetate (P<0.05). We conclude that mannitol in combination with HES 130/0.4 impairs clot propagation and clot strength in vitro. Fibrin clot strength impairment is more pronounced when mannitol is combined with HES than Ringer acetate. Our findings indicate that HES in combination with mannitol should be avoided whenever a disturbance in hemostasis is suspected during craniotomy.

Sitting position for removal of pineal region lesions: the Helsinki experience.

OBJECTIVE: To present a summary of anesthetic considerations for use of the sitting position in procedures to remove lesions of the occipital and suboccipital regions, with a special reference to the Helsinki experience with more than 300 operations in 1997-2007, and a retrospective study evaluating the incidence of venous air embolism (VAE) and hemodynamic stability in patients operated in the steep sitting position. METHODS: Anesthesiology reports of 72 patients with a mean (± standard deviation [SD]) age of 33 years ± 18 treated by the senior author (J.H.) for pineal region tumors using the infratentorial supracerebellar approach in the sitting position during an 11-year period were retrospectively reviewed for the incidence of VAE and hemodynamic stability. RESULTS: In the sitting position, median systolic blood pressure changed -8 (-95 to +50) mm Hg without alteration in heart rate. Based on patient records, the incidence of VAE was 19% (14 of 72 patients). In five patients, end-tidal carbon dioxide (ETCO(2)) decreased more than 0.7 kPa (5.25 mm Hg), possibly indicating VAE. Comparing patients with and without VAE, no differences in change of blood pressure, heart rate, or amount of administered vasoactive agents were observed. Postoperative duration of ventilator treatment and hospital stay were similar in patients with and without VAE. No signs of arterial embolization were seen postoperatively. CONCLUSIONS: The sitting position is associated with risk for hypotension. The same surgical approach and procedure does not exclude the occurrence of VAE. In this study, the unaltered hemodynamics in patients during VAE indicates relatively small VAE. Possible explanations for this are early recognition of air leakage and good cooperation between the surgical and anesthesia teams.