Continuous cerebral blood flow monitoring: What should we do with these extra numbers?

NeoDoppler is a noninvasive monitoring device that can be attached to patient's head provide real-time continuous cerebral Doppler evaluation. A feasibility study shows it used in operating theatres during anaesthesia potentially guide haemodynamic management. We discuss the impact of this new and which further research would necessary find its role clinical practice. In June 2023 issue BJA Open, Vik colleagues1Vik S.D. Torp H. Jarmund A.H. et al.Continuous blood flow general infants.BJA Open. 2023; 6100144Abstract Full Text PDF PubMed Google Scholar report first use (Cimon Medial AS, Trondheim, Norway). The ultrasound device, initially neonatal critical care.2Vik Follestad T. Støen R. Nyrnes S.A. NeoDoppler: technology for circulation neonates.Pediatr Res. 2020; 87: 95-103Crossref Scopus (12) It provides flow, traditionally obtained by indirect measures such as near infrared spectroscopy (NIRS) or direct snapshots perfusion using trained skilled operator at bedside. study, 30 infants referred noncardiac procedures under were recruited. They weighed 930–9530 g aged 0.10–140 days (gestational age: 24.6–41.4 weeks) on day surgery. authors decrease velocities, with end-diastolic value particularly marked (59% compared baseline) induction maintenance anaesthesia. Peak systolic time-averaged velocities reduced 26% 45%, respectively. All these values returned rapidly their baseline end recovery period. Contrary previous studies, was monitored continuously. NIRS remained stable throughout mean arterial pressure did not drop significantly. This particular interest because brings our attention an additional optimise anaesthetic management some most vulnerable patients. also promotes discussion whether, when, how treat patients if velocity observed. ‘What are effects developing brain?’ one 10 priority questions perioperative care listed James Lind Alliance National Institute Academic Anaesthesia. large part current area focuses toxicity drugs immature neurological system, especially induced widespread neuro-apoptosis alterations dendritic arborisation. Tremendous efforts have been made link observation neurocognitive deleterious children exposure anaesthesia.3Robinson E.J. Lyne T.C. Blaise B.J. Safety anaesthetics brain: we there yet?.BJA 2022; 2100012Abstract Recent results from GAS trial show single short (less than hour) sevoflurane associated complications 2 5 yr after anaesthesia.4Davidson A.J. Disma N. de Graaff J.C. al.Neurodevelopmental outcome years age awake-regional infancy (GAS): international multicentre, randomised controlled trial.Lancet. 2016; 387: 239-250Abstract Scholar,5McCann M.E. Dorris L. international, randomised, equivalence 2019; 393: 664-677Abstract (358) However, cognitive arise through multiple ways. An underlying condition sepsis inflammation surgery itself trigger neuro-biochemical mediators cross brain barrier affect central nervous system cells. Perioperative responsible injury; intraoperative hypoxia, hypotension, cardiac arrest require prompt responses avoid injury limit extent.6Merry A.F. Mitchell S.J. Complications anaesthesia.Anaesthesia. 2018; 73: 7-11Crossref (11) Even so, important note no association has between hypotension adverse outcomes young undergoing anaesthesia.7Gleich Flick Hu D. al.Neurodevelopment exposed anesthesia: design Mayo Anesthesia Kids (MASK) study.Contemp Clin Trial. 2015; 41: 45-54Crossref (83) Neonates, very low birthweights gestational age, higher risk anaesthesia-induced complications8Tiret Nivoche Y. Hatton F. Desmonts J.M. Vourc’h G. related children. prospective survey 40240 anaesthetics.Br J Anaesth. 1988; 61: 263-269Abstract global immaturity (cardiovascular, respiratory, neurological), specific anatomy, size. If risks emergence phases anaesthesia, complexity (positioning, duration, lungs vessels, haemorrhage, etc) source potential instability phase. Providing adequate thus identify surgical early possible correct them. Interestingly, colleagues,1Vik 80% cases, where used, classified major procedures, showing complex procedures. Maintaining good organ critical, heart. usually achieved neonates targeting mm Hg equivalent weeks patient. normal ranges well established. Adequate size positioning cuff should carefully considered. challenging obtain reliable preoperative measurement child crying agitated. There clear guidelines required specifically apart minimum standards set out Association Anaesthetists Great Britain Ireland.9Klein A.A. Meek Allcock E. al.Recommendations 2021.Anaesthesia. 2021; 76: 1212-1223Crossref (82) Recommendations include prevention hypothermia, fluid strategy, optimisation haemoglobin concentration.10Brindle McDiarmid C. Short K. al.Consensus intestinal surgery: enhanced Recovery After Surgery (ERAS®) society Recommendations.World Surg. 44: 2482Crossref (55) Regarding monitoring, choice invasive straightforward: factors govern anaesthetist skills experience, time pressures inserting line, vascular damage, nature sampling providing line real benefits gold standard output based thermodilution, catheterisation pulmonary artery line. patient weight restrictions equipment. evaluated less invasively echocardiography. Transthoracic echocardiography difficult theatre thorax easily accessible. Transoesophageal done small 1.7 kg.11Zyblewski S.C. Shirali G.S. Forbus G.A. al.Initial experience miniaturized multiplane transesophageal probe operations.Ann Thorac 2010; 89: 1990-1994Abstract (34) Both approaches user-dependent highly operators. Many devices developed overcome difficulties. Uncalibrated pulse contour systems option, but they still line.12Grensemann J. Cardiac analysis, technical basics less-invasive techniques.Front Med (Lausanne). 5: 64Crossref (32) Scholar,13Mehta Arora Newer methods monitoring.World Cardiol. 2014; 6: 1022-1029Crossref Their applications limited above 3 kg. Oesophageal >3 kg needs introduced positioned.14Raux O. Spencer A. Fesseau al.Intraoperative transoesophageal predict response volume expansion neonates.Br 2012; 108: 100-107Abstract (37) addition directly measure heart main other available. More localised try territories. NIRS15Yu Zhang Zong Meng Han Cerebral near-infrared oxygenation adults.Cochrane Database Syst Rev. 2018: CD010947Google typically applied forehead back kidneys, tissues. plethysmographic variability index may responsiveness anaesthetised neonates.16Desgranges F.P. Evain J.N. Pereira Souza Neto Raphael Desebbe Chassard Does mechanically ventilated children? meta-analysis.Br 117: 409-410Abstract (15) Scholar,17Bagci S. Müller Heydweiller Bartmann P. Franz A.R. pilot pleth indicator volume-responsive newborn surgery.J Anesth. 2013; 27: 192-198Crossref (22) Thoracic bioimpedance another approach, necessity access chest precludes many settings. transfontanellar Doppler.18Brackley Kilby M. Evans assessment fetal brain.in: Levene M.I. Chervenak F.A. Whittle M.J. Fetal neurology neurosurgery. £rd edition. Churchill Livingstone, London2001: 121-129Google Scholar,19Jarmund Pedersen Dudink scoping review waveforms infants.Ultrasound Biol. 49: 919-936Abstract (0) highlighted builds advantages. allows open fontanelle. user position probe, attach designed hat, troubleshoot repositioning case signal quality loss maintain same angle insonation ensure reproducibility data. does focus vessel (usually middle anterior Doppler), covers vessels hit beam fontanelle window. do any difficulties fontanelles. With more traditional Doppler, sometimes window, anatomical constraints, interest. broader approach NeoDoppler, arteries, taking measurements different depths simultaneously, probably explains difference. Additionally, seem 930g benefitting it. demonstrates utilised extended length time, extremely theatre. issues blinded attending surgery, suggesting interfere regular equipment, positioning. colleagues' demonstrating achievable, understand variables integrated into decision-making process. physiological rationale behind context autoregulation hypotension. physiology pathophysiology extensively studied paediatric intensive shown develop over life.20Kehrer Blumenstock Ehehalt Goelz Poets Schoning Development preterm two life.Pediatr 2005; 58: 927-930Crossref (69) Below threshold, lose ability constrict dilate change steady flow. neonates, autoregulatory threshold around 28–30 Hg. Further reductions lead functional (the function compromised) ischaemic structural integrity being reached. latter assumed 50% flow.21Perlman premature infant.in: Pearlman Neurology: neonatology controversies. 2nd Elsevier Saunders, 2012Google when considering thresholds neurodevelopmental known. No could established long-term neonates.22Camfferman Goederen Govaert al.Diagnostic predictive evaluation infants: systematic review.Pediatr 50-58Crossref (16) From standpoint, treatment appealing order make sure maintained: highlight certain degree leading inadequate perfusion. But need actively manage even anaesthesia? These will explored future trials including long term (5 yr) endpoints. Furthermore, treated? obviously discretion anaesthetist, who select treatments state identifying optimal dose ephedrine recently reported.23de Frykholm Ephedrine what target?.Br 130: 510-515Abstract Scholar,24Szostek A.-S. Saunier Elsensohn M.H. al.Effective 6 months multicentre controlled, label, escalation trial.Br 603-610Abstract (1) populations, corrections handled overload inotrope-induced hypertension catastrophic consequences oedema haemorrhages.23de Scholar,25Arumainathan Stendall Visram Management fluids surgery.BJA Educ. 18: 199-203Abstract (5) final target. Is it, adults, 20% below value,23de maybe combination elements, those provided NeoDoppler?26Holtby Skowno J.J. Kor D.J. R.P. Uezono New technologies pediatric anesthesia.Paediatr 22: 952-961Crossref (26) Once again, establish goal-directed inotropic therapy implementation care, monitor reliably, efficiently, continuously poses questions, regarding interpretation data integration unclear intervention, modalities, towards targets. Lastly, uncertain therapies better outcomes, whilst exposing burden inotrope therapy.