This was a two part study. Part one was a retrospective chart review to ascertain the prevalence and predictors of peri-operative complications in PWD receiving their dental care under general anesthesia (GA). Part two was a prospective survey of parents/caregivers regarding their satisfaction with the service as well as to ascertain the prevalence of post-operative symptoms incurred by patients. In Part 1, the prevalence of complications in PWD was 4 times higher than the 6% stated in the literature for the general population. Time under GA, and no previous history of dental care under GA were significantly related to complications. In Part 2, 100% of patients experienced post-operative symptoms; nonetheless, 92.7% of parents/caregivers were satisfied with the service provided. There prevalence of complications in the PWD in this study was high. Prior to treatment under GA, adequate pre-operative medical evaluations must be completed and time under GA minimized.

Despite the advances made in our understanding of the molecular mechanistic actions of general anesthetics very little is known about the in vivo neural circuits involved in creating the state of general anesthesia. To date the common consensus is that general anesthetics act ubiquitously within the CNS. Recently, (Devor and Zalkind, 2001) have reported that microinjections of pentobarbital (PB) into a discrete brainstem focal area of conscious rats induced a classical, reversible general anesthesia-like behavioral state. The authors concluded that this area, termed the mesopontine tegmental anesthesia area (MPTA), may be important for the induction of general anesthesia. The purpose of the present project was to study the neurophysiological basis of the analgesia, which accompanied the state of general anesthesia induced by PB microinjections into the MPTA that was reported by (Devor and Zalkind, 2001). Here, sensory inflow via the spinothalamic tract (STT), a classical spinal nociceptive pathway in the rat, was assessed using single neuron extracellular recording techniques before, during and after microinjections of PB into the MPTA. Spontaneous firing rate (SFR), antidromic firing index (FI) and sciatic as well as sural nerve-evoked responses (Sc-, Su-ER) of STT neurons in isoflurane-anesthetized rats were quantified before as well as 2, 15, 30 and 60 min following bilateral microinjections of either PB (200 micrograms/side) or vehicle control solution (Vh, 1 microliter/side) into the MPTA. The group mean SFR, FI as well as magnitudes of Sc-, Su-ER of STT neurons were significantly and reversibly reduced following PB microinjections compared to corresponding baseline measurements. There were no significant changes in any of the three parameters following microinjections of Vh compared to the pre-microinjection baseline responses. The results from this study indicate that analgesia, which occurs during the anesthesia-like state following microinjections of PB into the MPTA, may be due to attenuation of sensory inflow through the STT. The suppression of STT neurons likely occurs via direct and/or indirect descending pathways from the MPTA to the spinal cord. This study provides the first direct electrophysiological evidence for the analgesia caused by PB microinjections into the rat MPTA.

Despite the advances made in our understanding of the molecular mechanistic actions of general anesthetics very little is known about the in vivo neural circuits involved in creating the state of general anesthesia. To date the common consensus is that general anesthetics act ubiquitously within the CNS. Recently, (Devor and Zalkind, 2001) have reported that microinjections of pentobarbital (PB) into a discrete brainstem focal area of conscious rats induced a classical, reversible general anesthesia-like behavioral state. The authors concluded that this area, termed the mesopontine tegmental anesthesia area (MPTA), may be important for the induction of general anesthesia. The purpose of the present project was to study the neurophysiological basis of the analgesia, which accompanied the state of general anesthesia induced by PB microinjections into the MPTA that was reported by (Devor and Zalkind, 2001). Here, sensory inflow via the spinothalamic tract (STT), a classical spinal nociceptive pathway in the rat, was assessed using single neuron extracellular recording techniques before, during and after microinjections of PB into the MPTA. Spontaneous firing rate (SFR), antidromic firing index (FI) and sciatic as well as sural nerve-evoked responses (Sc-, Su-ER) of STT neurons in isoflurane-anesthetized rats were quantified before as well as 2, 15, 30 and 60 min following bilateral microinjections of either PB (200 micrograms/side) or vehicle control solution (Vh, 1 microliter/side) into the MPTA. The group mean SFR, FI as well as magnitudes of Sc-, Su-ER of STT neurons were significantly and reversibly reduced following PB microinjections compared to corresponding baseline measurements. There were no significant changes in any of the three parameters following microinjections of Vh compared to the pre-microinjection baseline responses. The results from this study indicate that analgesia, which occurs during the anesthesia-like state following microinjections of PB into the MPTA, may be due to attenuation of sensory inflow through the STT. The suppression of STT neurons likely occurs via direct and/or indirect descending pathways from the MPTA to the spinal cord. This study provides the first direct electrophysiological evidence for the analgesia caused by PB microinjections into the rat MPTA. / Pharmaceutical Sciences, Faculty of / Graduate

Background: Laryngospasm is a common and often serious adverse respiratory event encountered during anesthetic care of children. We examined, in a case control design, the risk factors for laryngospasm in children. Material and Methods: The records of 130 children identified as having experienced laryngospasm under general anesthesia were examined. Cases were identified from those prospectively entered into the Mayo Clinic performance improvement database between January 1, 1996 and December 31, 2005. Potential demographic, patient, surgical and anesthetic related risk factors were determined in a 1 : 2 case-control study. Results: No individual demographic factors were found to be significantly associated with risk for laryngospasm. However, multivariate analysis demonstrated significant associations between laryngospasm and intercurrent upper respiratory infection (OR 2.03 P = 0.022) and the presence of an airway anomaly (OR = 3.35, P = 0.030). Among those experiencing laryngospasm during maintenance or emergence, the use of a laryngeal mask airway was strongly associated even when adjusted for the presence of upper respiratory infection and airway anomaly (P = 0.019). Ten patients experienced postoperatively one or more complications whereas only three complications were observed among controls (P = 0.008). No child required cardiopulmonary resuscitation and there were no deaths in either study cohort. Conclusions: In our pediatric population, the risk of laryngospasm was increased in children with upper respiratory tract infection or an airway anomaly. The use of laryngeal mask airway was found to be associated with laryngospasm even when adjusted for the presence of upper respiratory tract infection and airway anomaly.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18859号 / 医博第3970号 / 新制||医||1008(附属図書館) / 31810 / 京都大学大学院医学研究科医学専攻 / (主査)教授 渡邊 直樹, 教授 渡邉 大, 教授 松原 和夫 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・論文博士 / 博士(医学) / 乙第12970号 / 論医博第2103号 / 新制||医||1012(附属図書館) / 32408 / 新制||医||1012 / 京都大学大学院医学研究科医学専攻 / (主査)教授 小池 薫, 教授 三嶋 理晃, 教授 中山 健夫 / 学位規則第4条第2項該当 / Doctor of Medical Science / Kyoto University / DGAM

In order to further explore the nature of anesthesia-induced unconsciousness and its relationship to nociception, investigators attempted to determine whether mismatch negativity could be detected during general anesthesia and surgery. An auditory odd-ball paradigm designed to elicit mismatch negativity was presented to ten patients during general anesthesia and surgery. Five of the ten also underwent testing in the awake state prior to surgery. Multiple EEG recordings were obtained in each patient and each condition using the BioSemi ActiveTwo 64 EEG electrode system. The anesthetic regime required only that 0.7 MAC of an inhaled agent was administered. Several methods of analysis were utilized to determine whether an MMN response could be identified: visual inspection of ERP waveforms, targeted t-tests, cluster permutation tests, and multivariate pattern analysis. Whereas deviant-related negativity was readily detected in the awake state, deviant-related negativity was not detected during surgery and general anesthesia. Results demonstrate that essential components of the MMN response are abolished during typically conducted general anesthesia even with significant surgical stimulation. These results are consistent with previous research on ERPs and anesthesia. Results cast doubt on the possibility of sensory memory related to intraoperative events. / Thesis / Master of Science (MSc)

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