Patterns of Hysteresis Between Induction and Emergence of Neuroanesthesia are Present in Spinal and Intracranial Surgeries

Background: Recovery of consciousness is usually seen as a passive process, with emergence from anesthesia depicted as the inverse process of induction resulting from the elimination of anesthetic drugs from their central nervous system sites of action. However, that need not be the case. Recently it has been argued that we might encounter hysteresis to changes in the state of consciousness, known as neural inertia. This phenomenon has been debated in neuroanesthesia, as manipulation of the brain might further influence recovery of consciousness. The present study is aimed at assessing hysteresis between induction and emergence under propofol-opioid neuroanesthesia in humans using estimated propofol concentrations in both spinal and intracranial surgeries. Methods: We identified the moments of loss (LOR) and recovery of responsiveness (ROR) in 21 craniotomies and 25 spinal surgeries. Propofol was given slowly until loss of responsiveness and stopped at the end of surgery. An opioid was present at induction and recovery. Propofol infused was recorded and plasma and effect-site concentrations were estimated using 2 pharmacokinetic models. Dose-response curves were generated. Estimated propofol plasma and effect-site concentrations were compared to assess hysteresis. Results: Estimated propofol concentrations at LOR and ROR showed hysteresis. Whether for spinal or intracranial surgeries, the EC50 of propofol at which half of the patients entered and exited the state of responsiveness was significantly different. Conclusions: Hysteresis was observed between propofol concentrations at LOR and ROR, in both patients presenting for spinal and intracranial surgeries. Manipulation of the brain does not appear to change patterns of hysteresis, suggesting that neural inertia may occur in humans, in a way similar to that found in animal species. These findings justify performing a clinical study in patients using measured propofol concentrations to assess neural inertia. Supported by the Fundação para a Ciência e Tecnologia with the reference projects SFRH/BD/98915/2013 and UID/SEM/50022/2013. The authors have no conflicts of interest to disclose. Address correspondence to: Ana Leitão Ferreira, MSc, MS, Center of Clinical Investigation in Anesthesiology, Service of Anesthesiology, Hospital Center of Porto, Largo Professor Abel Salazar, 4099-001 Porto, Portugal (e-mail: ana.leitao.ferreira@gmail.com). Received April 12, 2018 Accepted September 14, 2018 Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved

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Journal Club

No abstract available

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Acute cholecystitis and gallbladder perforation leading to massive haemoperitoneum in a patient taking rivaroxaban

We present the case of an 80-year old man taking rivaroxaban for atrial fibrillation who sustained massive intra-abdominal bleeding in the setting of acute cholecystitis. CT scan on admission revealed evidence of active bleeding into the gallbladder lumen and gallbladder perforation. Immediate resuscitation was commenced with intravenous fluids, antibiotics and blood products. Despite attempts to correct coagulopathy, the patient's haemodynamic status deteriorated and an emergency laparotomy was performed, with open cholecystectomy, washout and haemostasis. The patient had a largely uneventful recovery and was discharged on day 11 of admission. Patients with coagulopathies, whether pharmacological or due to underlying disease processes, are at very high risk of severe haemorrhagic complications and subsequent morbidity. As such, prompt recognition and operative management of haemorrhagic perforated cholecystitis is of crucial importance.

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Infection of a tophaceous nodule of the wirst and hand

Tophaceous gout occurs years after recurrent attacks of acute inflammatory arthritis. The urate deposits are incriminated in the inflammatory process; however, their infection is exceptional. We report the observation of an infected gouty tophus of the pinky and the wrist of a 40-year-old man, presented as an excruciating inflammatory pain with buff-yellow swelling of the fifth right finger and wrist in a febrile context. As a matter of fact, the evolution was favourable after surgical excision and antibiotic therapy. The infection of a tophus is an exceptional complication of the gout. In daily practice, this diagnosis is really a difficult challenge for the clinician. The systematic bacteriological examination of the tophi with cutaneous fistulation is necessary to introduce prematurely an adapted treatment.

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Rare extraspinal cause of acute lumbar radiculopathy

A 60-year-old man presented to an outpatient pain management clinic with antalgic gait and left lower extremity (LLE) radiculopathy from an unknown aetiology. A lumbar MRI revealed minimal disc protrusion at L3 and a partially visualised left-sided kidney abnormality. Abdominal and pelvic CT demonstrated severe hydronephrosis of the left kidney compressing the left psoas major. The patient was immediately referred to an outside hospital for nephrology workup, and following nephrostomy tube, his radicular pain resolved. He remained asymptomatic at 4 weeks follow-up. We found two cases of postsurgical, retroperitoneal fluid collection that caused lumbar radiculopathy, but none associated with hydronephrosis. To our knowledge, this is the first case in the literature to report hydronephrosis as the potential aetiology of lumbar radiculopathy, which highlights an important clinical reminder: to consider extraspinal aetiologies in all patients who present with lumbar radiculopathy, when clinical symptoms, examination findings and diagnostic studies present with unusual characteristics.

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Coexisting polyarticular septic arthritis, gout and pseudogout

A case of a 67-year-old man with coexisting polyarticular septic arthritis due to group G Streptococcus, gout and pseudogout is presented. Septic arthritis of the left knee joint was further complicated by the development of an adjacent osteomyelitis. Appropriate management led to a full clinical recovery. Atypical clinical presentations in elderly, need for a sampling of more than one joint in polyarthritis and a summary of similar cases in literature is discussed.

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Rare vascular complication of acute meningococcal meningitis in a child

Description 

A 5-year-old boy presented with fever for 4 days and acute-onset weakness of the right upper and lower limb for 1  day. There was no history of headache, seizures, vomiting and altered sensorium, rash or bleeding from any site. On examination, he had normal mentation, neck stiffness, Kernig's sign, right-sided upper motor neuron facial palsy and right hemiparesis. The rest of the systemic examination was unremarkable. A clinical diagnosis of acute meningitis with left Middle Cerebral Artery (MCA) territory stroke was made.

Cerebrospinal fluid examination revealed 980 cells/µL (90% polymorphonuclear leucocytes and 10% lymphocytes), glucose 47 mg/dL, proteins 110 mg/dL and Neisseria meningitides antigen was positive; however, no organism could be isolated on microscopy and culture. He was unimmunised for meningococcal vaccine. Blood culture was sterile. Detailed stroke and immune deficiency work-up was negative. MRI of the brain showed altered signal changes in left frontal lobe, anterior limb of the internal capsule,...

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Unique retroinnominate course of the left brachiocephalic vein

Description  

A 4-year-old girl diagnosed with tetralogy of Fallot on transthoracic echocardiogram, was referred for a CT angiography (CTA) for preoperative anatomical assessment of the primary cardiac defect and associated cardiovascular anomalies. Review of CTA images revealed a unique anomalous course of the left brachiocephalic vein (*) where it was seen crossing the midline above the arch, anterior to the left common carotid artery (LCCA) and left subclavian artery (LSCA) but coursing posterior to the innominate artery, before joining the right brachiocephalic vein (RBCV) to form the right superior vena cava (RSVC) (figure 1A–D).

Figure 1

Volume rendered and axial maximum intensity projection images of CT angiography  (A–D) depicts the left brachiocephalic vein (*) traversing anterior to the left subclavian artery and left common carotid artery and posterior to the innominate artery, before joining the right brachiocephalic vein. LCCA, left common carotid artery; LSCA, left subclavian artery; RBCV, right...

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