Paolo Zanatta

Publications (16) View all

• Article: The human brain pacemaker: Synchronized infra-slow neurovascular coupling in patients undergoing non-pulsatile cardiopulmonary bypass.

  Paolo Zanatta, Gianna Maria Toffolo, Elisa Sartori, Anna Bet, Fabrizio Baldanzi, Nivedita Agarwal, Eugene Golanov
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  ABSTRACT: In non-pulsatile cardiopulmonary bypass surgery, middle cerebral artery blood flow velocity (BFV) is characterized by infra-slow oscillations of approximately 0.06Hz, which are paralleled by changes in total EEG power variability (EEG-PV), measured in 2s intervals. Since the origin of these BFV oscillations is not known, we explored their possible causative relationships with oscillations in EEG-PV at around 0.06Hz. We monitored 28 patients undergoing non-pulsatile cardiopulmonary bypass using transcranial Doppler sonography and scalp electroencephalography at two levels of anesthesia - deep (prevalence of burst suppression rhythm) and moderate (prevalence of theta rhythm). Under deep anesthesia, the EEG bursts suppression pattern was highly correlative with BFV oscillations. Hence, a detailed quantitative picture of the coupling between electrical brain activity and BFV was derived, both in deep and moderate anesthesia, via linear and non linear processing of EEG-PV and BFV signals, resorting to widely used measures of signal coupling such as frequency of oscillations, coherence, Granger causality and cross-approximate entropy. Results strongly suggest the existence of coupling between EEG-PV and BFV. In moderate anesthesia EEG-PV mean dominant frequency is similar to frequency of BFV oscillations (0.065±0.010Hz vs 0.045±0.019Hz); coherence between the two signals was significant in about 55% of subjects, and the Granger causality suggested an EEG-PV■BFV causal effect direction. The strength of the coupling increased with deepening anesthesia, as EEG-PV oscillations mean dominant frequency virtually coincided with the BFV peak frequency (0.062±0.017Hz vs 0.060±0.024Hz), and coherence became significant in a larger number (65%) of subjects. Cross-approximate entropy decreased significantly from moderate to deep anesthesia, indicating a higher level of synchrony between the two signals. Presence of a subcortical brain pacemaker that drives vascular infra-slow oscillations in the brain is proposed. These findings allow to suggest an original hypothesis explaining the mechanism underlying infra-slow neurovascular coupling.
  NeuroImage 01/2013; · 5.89 Impact Factor
• Article: Change in behavioral functional capacity is associated with preexisting cognitive function rather than with cognitive decline in patients 1 year after cardiac surgery.

  Simone Messerotti Benvenuti, Elisabetta Patron, Paolo Zanatta, Elvio Polesel, Carlotta Bonfà, Daniela Palomba
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  ABSTRACT: OBJECTIVE: The objective was to examine whether preexisting cognitive function rather than cognitive decline associated with intraoperative procedures may predict change in behavioral functional capacity in patients 1 year after cardiac surgery. METHOD: Forty-five patients completed a cognitive evaluation, including the Trail Making Test part B (TMT-B) for attention and psychomotor speed, the Memory with 10-s interference for working memory, the Digit Span test for short-term memory and the Instrumental Activities of Daily Living (IADLs) questionnaire for behavioral functional capacity, before surgery and 1 year after cardiac surgery. RESULTS: Sixteen patients (36%) exhibited cognitive decline after cardiac surgery. Preoperative scores on TMT-B significantly predicted change in behavioral functional capacity as measured by IADLs (beta=0.371, P<.05), whereas the postoperative cognitive decline and intraoperative variables were unrelated to residualized change scores in IADLs (all Ps>.08). CONCLUSIONS: Preexisting cognitive dysfunctions as assessed by TMT-B can be a marker of preoperative brain dysfunction, which, in turn, in addition to brain damage caused by cardiac surgery procedures, may further predispose patients to poor behavioral functional capacity and outcome 1 year after surgery. Impaired cognitive functions before surgery should be considered when evaluating the effects of cardiac surgery procedures on long-term behavioral functional status of patients.
  General hospital psychiatry 01/2013; · 2.67 Impact Factor
• Source

  Available from: Daniela Palomba

  Article: Pain-related somatosensory evoked potentials and functional brain magnetic resonance in the evaluation of neurologic recovery after cardiac arrest: a case study of three patients.

  Paolo Zanatta, Simone Messerotti Benvenuti, Fabrizio Baldanzi, Matteo Bendini, Marsilio Saccavini, Wadih Tamari, Daniela Palomba, Enrico Bosco
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  ABSTRACT: This case series investigates whether painful electrical stimulation increases the early prognostic value of both somatosensory-evoked potentials and functional magnetic resonance imaging in comatose patients after cardiac arrest. Three single cases with hypoxic-ischemic encephalopathy were considered. A neurophysiological evaluation with an electroencephalogram and somatosensory-evoked potentials during increased electrical stimulation in both median nerves was performed within five days of cardiac arrest. Each patient also underwent a functional magnetic resonance imaging evaluation with the same neurophysiological protocol one month after cardiac arrest. One patient, who completely recovered, showed a middle latency component at a high intensity of stimulation and the activation of all brain areas involved in cerebral pain processing. One patient in a minimally conscious state only showed the cortical somatosensory response and the activation of the primary somatosensory cortex. The last patient, who was in a vegetative state, did not show primary somatosensory evoked potentials; only the activation of subcortical brain areas occurred. These preliminary findings suggest that the pain-related somatosensory evoked potentials performed to increase the prognosis of comatose patients after cardiac arrest are associated with regional brain activity showed by functional magnetic resonance imaging during median nerves electrical stimulation. More importantly, this cases report also suggests that somatosensory evoked potentials and functional magnetic resonance imaging during painful electrical stimulation may be sensitive and complementary methods to predict the neurological outcome in the acute phase of coma. Thus, pain-related somatosensory-evoked potentials may be a reliable and a cost-effective tool for planning the early diagnostic evaluation of comatose patients.
  Scandinavian Journal of Trauma Resuscitation and Emergency Medicine 03/2012; 20:22. · 1.85 Impact Factor
• Article: Cortical and autonomic responses to noxious stimulation during anesthesia in cardiac surgery patients are moderated by preanesthetic blood pressure levels.

  Simone Messerotti Benvenuti, Christopher Ring, Daniela Palomba, Fabrizio Baldanzi, Paolo Zanatta
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  ABSTRACT: Evidence has revealed that elevated blood pressure is associated with reduced sensitivity to noxious stimulation. The current study investigated the association between resting blood pressure and nociception during anesthesia in 32 patients undergoing cardiac surgery. Pain-related middle latency cortical somatosensory evoked potentials (MLCEPs) elicited by noxious 50 mA median nerve stimulation were used to assess intraoperative nociception and algesia. Noxious stimulation elicited MLCEPs in 18 (56%) patients. Resting blood pressure was significantly higher in patients without MLCEP than those with MLCEP. Moreover, systolic blood pressure responses to intraoperative electrical stimulation of median nerve were blunted in the group without MLCEP compared to those with MLCEP. The current findings extend the hypertensive hypoalgesia phenomenon to the operating theatre.
  Psychophysiology 02/2012; 49(5):697-703. · 3.29 Impact Factor
• Article: Preoperative cerebral hypoperfusion in the left, not in the right, hemisphere is associated with cognitive decline after cardiac surgery.

  Simone Messerotti Benvenuti, Paolo Zanatta, Carolina Longo, Anna Paola Mazzarolo, Daniela Palomba
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  ABSTRACT: Postoperative cognitive decline (POCD) is a frequent complication after cardiac surgery. Although intraoperative events are risk factors for POCD, the role played by preoperative hypoperfusion in cognitive decline has not yet been investigated. It is also unknown whether the impact of preoperative hypoperfusion in the left or right middle cerebral arteries (MCAs) can differentially account for POCD. The main aims of this study were to investigate whether preoperative cerebral hypoperfusion was associated with early POCD and whether lateralized hypoperfusion would differentially affect POCD in patients after cardiac surgery. Bilateral MCA continuous transcranial Doppler (TCD) sonography was preoperatively performed at rest in 31 right-handed patients who underwent cardiac surgery to detect cerebral blood flow (CBF) velocity. All patients completed a neuropsychological evaluation to assess attention, short-term memory, working memory, and psychomotor function before surgery and at discharge. POCD was defined using the standard deviation method. Logistic regression was used to investigate the association between hypoperfusion and POCD, controlling for common preoperative risk factors. Fourteen patients (45%) exhibited POCD. Cerebral hypoperfusion in the left MCA selectively predicted the incidence of POCD (odds ratio = 0.90, p < .02), whereas CBF velocity in the right MCA was unrelated to POCD (odds ratio = 1.07, p = .39). Patients who underwent cardiac surgery with reduced CBF velocity in the left MCA preoperatively are at greater risk for POCD. Left cerebral hypoperfusion may also represent an independent predictor of POCD in these patients. TCD evaluation may have substantial clinical benefits for the detection of patients at high risk of POCD after cardiac surgery.
  Psychosomatic Medicine 12/2011; 74(1):73-80. · 3.97 Impact Factor