Hypoglycemia as a possible factor in the induction of vasovagal syncope.

Glucose level was estimated in capillary blood of 16 patients, who had vasovagal syncope during exodontia with local anaesthesia. One consistent finding was the low blood sugar level in all patients during syncope, as compared with the level 1 hour after recovery. Hypoglycemia can be induced by parasympathetic activation; this may be the product of reflex conditioning. Modest lowering of blood sugar levels can also act in synergy with hypotension and hypocapnea to induce loss of consciousness. Psychogenic syncope may be mediated through a mechanism involving hypoglycemia. Reflex conditioning perhaps accounts for the small but consistent fraction of the adult population who have repeated fainting episodes.     

Malignant vasovagal syncope

We report the case of a 21-year-old male whose frequent episodes of loss of consciousness in the dental surgery culminated in the postponement of treatment, pending further investigation. The patient was referred to a cardiologist and submitted to head-up tilt testing, which evoked prolonged asystole, associated with loss of consciousness and mild generalized twitching, confirming a diagnosis of malignant vasovagal syncope. Before dental treatment could be completed, the patient was successfully treated with disopyramide and dual-chamber pacemaker implantation. CLINICAL RELEVANCE: Dentistry can predispose patients to fainting (syncope or vasovagal episode) owing to fear, pain, unusual sights and smells, anxiety, fatigue and fasting, so knowledge of extreme forms of this response are of relevance.     

Cardiac dysrhythmias complicating maxillofacial surgery

Cardiac asystole, bradycardia and other dysrhythmias are complications associated with surgery of the craniofacial and maxillofacial structures. These dysrhythmias have been discussed frequently in ophthalmology but less attention has been paid to this problem in the maxillofacial surgery literature. Eight patients, 6 men and 2 women, who underwent maxillofacial surgery during a 16-month period at the Victoria General Hospital, Halifax, Canada demonstrated either asystole or bradycardia. This group of patients represents 1.6% of the total number of patients treated during the 16-month period. Six patients demonstrated either asystole or bradycardia during stretching of the soft tissues associated with advancement of the maxilla after bony mobilization. Two patients had either asystole or bradycardia during manipulation of the temporalis muscle fibres during surgery to correct total bony ankylosis of the temporomandibular joint. The etiology of this relatively rare but troublesome complication is discussed.     

A study of hemodynamic effects during dental treatment under local anesthesia. Observation of parasympathetic activity based on the index of R-R interval variation in ECG

Observing hemodynamic changes occurring during dental treatment performed under local anesthesia is very important. Although many reports on such changes have been made on the basis of blood pressure and heart rate indexes, few have been made on the basis of parasympathetic activity. This is a report of a study on observations of parasympathetic activity on the basis of the index of R-R interval variation in ECG. A multipurpose monitoring system was used to observe and record hemodynamic changes in 52 patients undergoing dental treatment under local anesthesia. In addition, parasympathetic activity was observed on the basis of the index of the coefficient of variation of the R-R interval in ECG (CVR-R = SD/MEAN x 100%). To evaluate R-R interval variations in ECG during dental treatment clearly, comparisons were made between subjects to whom atropine sulfate was administered (prior to treatment) and subjects to whom no drug was administered. In instances of which the subject experiences no unpleasant symptom (for instance, the fainting) during dental treatment, comparative examinations of R-R interval variations in ECG were made at various points during the course of therapy. In instances of which the fainting was induced, examinations of these variations were made during, before, and after the occurrence of the fainting. Results and Conclusions 1. In measuring R-R interval variations in ECG, maintaining stable heart rates and respiratory frequency and depth made it possible to evaluate parasympathetic activity during dental treatment. 2. Consistently low CVR-R values after administration of atropine sulfate clearly showed that patients treated in this way were in a state of parasympathetic blockade. 3. Patients to whom atropine sulfate was administered demonstrated higher values for systolic and diastolic blood pressure and for heart rate than controls: and their posttreatment recovery was slower. 4. Increasing age produced a correlative decrease in CVR-R during both the pretreatment rest period and immediately before treatment. 5. Systolic and diastolic blood pressure and heart rate increased at local anesthesia and maintained such levels until the end of treatment in no fainting cases, however, CVR-R increased just before the end of treatment. This finding leads to the assumption that, as a result of intensified sympathetic activity at the initial stage and the maintenance of this condition, parasympathetic activity increases just before the end of therapy to keep hemodynamic activity in balance.(ABSTRACT TRUNCATED AT 400 WORDS)     

Syncope in the dental environment

Syncope or Fainting is, by far, the most common emergency situation in the dental practice. Syncope is defined as an abrupt, transient, short term loss of consciousness and postural tone, followed by spontaneous and complete recovery. The pathophysiology of syncope consists of a sudden cessation or decrease in cerebral perfusion. Differential diagnosis of these medical conditions is of paramount importance in uncovering unrecognized systemic diseases. The dental team plays an important role in the process of establishing the correct diagnosis by its ability to recognize and document all the clinical symptoms and signs evident at the time of fainting. The dental surgeon is expected to be familiar with the various etiologies of syncope and should be able to differentiate between them. This article provides the essentials of the diagnostic procedure and an approach to the evaluation of the unconscious patient.     

Vasovagal syncope in heart transplant patients during dental surgery

The pathogenesis of vasovagal syncope during emotional stress is controversial. Several authors have postulated that the vasodepressor response in humans may be initiated by C-fiber mechanoreceptors situated in the heart and connected via cardiac vagal afferents to the medullary center for cardiovascular control. It has been argued that heart transplant patients cannot show any vasovagal reaction because the donor heart is transplanted completely deprived of any vagal or sympathetic innervation. In this report, however, 3 episodes of vasovagal syncope are documented in 3 heart transplant patients undergoing periodontal surgery. During vasovagal syncope in each of these patients, a dramatic fall in systolic blood pressure (from 137 +/- 5 mmHg to 76 +/- 3.6 mmHg) was detected, but, in contrast to what is observable in normal subjects, the heart rate did not show any relevant change (from 96.7 +/- 4.5 beats per minute to 102.6 +/- 7.6 beats per minute). These unexpected findings emphasize the marginal role of the heart on the pathogenesis of the vasovagal syncope and underline the fact that a vasovagal reaction can develop even in the absence of the bradycardia that is the primary symptom usually reported in the literature.     

Orthognathic surgery with or without induced hypotension

This study involved a retrospective evaluation of patients subjected to surgery for dentofacial deformities treated without induced controlled hypotension (group I, n = 50) and a prospective evaluation of patients who were subjected to surgery under hypotensive general anaesthesia (group II, n = 50). No statistical differences were found between the study groups with regard to the duration of surgery. However, there were statistically significant differences in the need for blood transfusion and the occurrence of bradycardia during the maxillary down-fracture. Hypotensive anaesthesia decreased the need for a blood transfusion and the occurrence of bradycardia, and is therefore considered highly beneficial for patients undergoing orthognathic surgery.     

Trigemino-Cardiac Reflex During Orbital Floor Reconstruction: A Case Report and Review

Trigemino-cardiac reflex is occurrence of hypotension and bradycardia upon surgical manipulation of areas supplied by the trigeminal nerve, and has been reported during craniofacial maxillofacial and ocular surgeries. Communication between the anaesthetic and surgical team is essential, and cessation of the precipitating stimulus is the first and most important therapeutic step. We report a case of immediate, reproducible, and reflexive response of Bradycardia and dysrhythmia upon manipulation of orbital fracture during orbital floor reconstruction in a 65-year-old man. Upon recognition of the reproducible relationship between falcine stimulation and increased vagal tone, the patient was given atropine in an effort to block cholinergic hyperactivity. After atropine administration, no further dysrhythmias occurred and surgery was carried uneventfully.     

Sinus bradycardia related to temporomandibular joint surgery

The carotid artery lies in close relationship to the temporomandibular joint (TMJ). Manipulation of the mandible during TMJ surgery has been observed in several cases to be directly associated with the development of sinus bradycardia as the joint is distracted during arthrotomy and arthroplasty procedures. We report several cases and discuss differential diagnosis of sinus bradycardia associated with positional changes of the TMJ. This report emphasizes the importance to the surgeon and to the anesthesiologist of recognition of this cardiac phenomenon, mediated through the trigeminovagal reflex, to appropriately manage the patients during TMJ surgery.     

New protocol to prevent TMJ reankylosis and potentially life threatening complications in triad patients

The management of patients with the triad of temporomandibular joint (TMJ) ankylosis, micrognathia and obstructive sleep apnea syndrome is challenging for the oral and maxillofacial surgeon because it involves achieving the desired oral opening, correction of micrognathia, and correction of the obstructed airway. Seven of the authors’ triad patients, in whom only the release of ankylosis was performed, developed bradycardia and respiratory distress during postoperative jaw physiotherapy, leading to their non-compliance for active jaw physiotherapy and subsequent reankylosis. This paper suggests a new surgical protocol for the management of patients with the triad, to achieve correction of the obstructed airway, relief of the respiratory distress symptoms, correction of micrognathia and restricted mouth opening. It also provides a logical reason for the occurrence of bradycardia following ankylosis release and its potential role in TMJ reankylosis. It emphasizes that the occurrence of bradycardia in triad patients during jaw exercises is dictated by the severity of their apnea–hypopnea index and the degree of narrowing of their posterior airway space. The recognition and prevention of this by the new protocol is discussed in 7 patients.     

牙拔除术患者并发晕厥38例的原因分析及防治措施

目的回顾分析我科2006年1月—2008年12月牙拔除术患者并发晕厥的原因及采取的防治措施。方法采取详细询问调查的方法,了解患者牙拔除术前的精神状况、心理状态、既往拔牙史及全身情况等,手术中仔细观察患者,做好全面记录。结果晕厥的发生与患者的年龄有关,20-40岁是牙拔除术并发晕厥的高危人群,初次拔牙、拔牙前的心理准备不充分、紧张恐惧及惧怕疼痛对晕厥反应的发生影响较大。结论牙拔除术前详细询问病史,严格掌握牙拔除术适应证,认真做好诊前3min交流,安慰疏导患者,消除患者紧张恐惧心理;牙拔除术中密切观察患者,发现异常情况,医护紧密配合采取相应的处理措施,对预防晕厥发生、保障患者安全及手术顺利进行至关重要。     

右美托咪定预防老年口腔肿瘤患者术后谵妄的疗效分析

目的 评价右美托咪定预防老年口腔肿瘤患者术后谵妄的临床效果。方法选取156例在全麻下行根治术的老年口腔肿瘤患者,随机分为观察组（78例）和对照组（78例）。所有患者手术结束后经过2 h的麻醉复苏室过渡后转入SICU。随后,观察组给予静脉泵注生理盐水稀释的右美托咪定注射液0.2μg/(kg·h)维持12 h,对照组给予等体积的生理盐水静脉泵注。所有患者术后都给予同样剂量的曲马多+托烷司琼镇痛。在术后3 d内,每天8:00和20:00按照CAM-ICU（confusion assessment method for the intensive care unit）方法评估谵妄发生情况,并进行VAS疼痛评分和Richmond镇静躁动评分（richmond agitation sedation scale,RASS）。采用SPSS16.0软件包对数据进行统计学分析。结果观察组患者术后疼痛评分、术后心动过缓和低血压发生率与对照组比较无显著差异,2组均无呼吸抑制发生。观察组术后第1天及第2天的镇静躁动评分优于对照组。观察组术后谵妄、恶心、呕吐发生率低于对照组。结论右美托咪定术后0.2 μg/kg.h 维持12 h,可改善老年口腔肿瘤患者的术后镇静状况,减少术后谵妄发生,且不会引起心动过缓及低血压。     

Trigemino-Cardiac Reflex: A Phenomenon Neglected in Maxillofacial Surgery?

Background

Trigemino-cardiac reflex is a physiologic response of the body to pressure effects in the region of distribution of the trigeminal nerve. Oral and maxillofacial surgical procedures can induce the development of this reflex, which leads to significant changes in the heart rate and sinus rhythms. This study intends to evaluate the effects of this reflex in patients with facial fractures and its subsequent management.

Patients and Methods

A total of thirty-seven patients with facial fractures who reported to the Department of Oral and Maxillofacial Surgery at Basaveswar Teaching and General Hospital, Gulbarga during a period from July 2015–March 2016 were considered for the study.

Results

A male preponderance is observed with the most susceptible age group being 21–30 years. Twenty-three patients sustained mid-facial fractures alone, nine patients had isolated mandible fractures and five patients had fractures of both the mid-face and mandible. A relative bradycardia was observed in the patients with mid-facial trauma, both at the time of presentation and also during the surgical reduction of midfacial fractures which improved after completion of procedure in most of the patients. However, in two patients, the bradycardia progressed to a cardiac asystole during midface manipulation which required immediate halt of the procedure and intravenous administration of atropine.

Conclusion

Trigeminocardiac reflex though physiologic, which usually tends to subside without complications is not to be neglected in the surgeries of the maxillofacial skeleton. A propensity for unforeseen complications due to this reflex has to be avoided by meticulous monitoring of the ECG.

     

Nasal and cerebral blood filling in patients with congenital cleft palate and allergic rhinitis]

Nasal mucosa and brain blood content was studied by rheographic methods in 100 normal subjects aged 4 to 48, in 184 patients with various types of cleft palate, and in 129 ones with allergic rhinitis. A combined restructuring of the nasal and cerebral blood content was revealed in the patients, seen first of all on rheoencephalograms; other shifts included increased vascular tone and impaired venous outflow.     

Trigeminocardiac reflex: a unique case of recurrent asystole during bilateral trigeminal sensory root rhizotomy.

BACKGROUND: The trigeminocardiac reflex is the sudden-onset of dysrhythmia and hypotension during manipulation of any of the branches of the trigeminal nerve. The trigeminal nerve and cardioinhibitory vagus nerve constitute the afferent and efferent pathways in the reflex arc. The trigeminocardiac reflex has been reported to occur during craniofacial surgery, balloon-compression rhizolysis of the trigeminal ganglion, and tumour resection in the cerebellopontine angle. PATIENT & METHOD: A 2-year-old male patient with haemangioma near the sella turcica underwent rhizotomies of both sides of the dorsal sensory roots, of the trigeminal nerves for palliation of intractable trigeminal pain. RESULTS: In this report, we experienced two unexpected episodes of asystole after transection of the sensory roots of the trigeminal nerves. CONCLUSION: Sectioning of the intracranial dorsal sensory root of the trigeminal nerve provides clear evidence of the central role of the trigeminal nerve as the afferent pathway of the trigeminocardiac reflex arc.     

Dental trauma after cardiac syncope in a patient with long QT syndrome

Dental trauma secondary to a syncopal episode occurs rarely in the pediatric population. Although the majority of these events occurs in patients with a benign medical history, a subset of these cases occur in patients with a genetic predisposition to cardiac arrhythmia. Long QT syndrome, characterized by prolonged cardiac ventricular repolarization, represents one genetic condition in which patients sustain events of seizure, syncope, and sudden cardiac death in response to precipitating physical, mental, or emotional stressors. In this case report, extensive dental injuries occurred after an episode of cardiac syncope in a patient with a dual presentation of long QT syndrome and Pierre Robin sequence. The purpose of this paper was to highlight the potentially malignant course of symptomatic long QT syndrome and emphasize the importance of warning sign recognition and multidisciplinary medical management of pediatric patients with this condition.     

Measurement of volume changes after sinus floor augmentation with a phycogenic hydroxyapatite

PURPOSE: The purpose of this study was the determination of time-dependent volumetric changes of particulate sinus inlay grafts. A mixture of phycogenic hydroxyapatite (Algipore/C-Graft) and autologous bone collected from the surgical access area was used as the grafting material. MATERIALS AND METHODS: Thirty-three sinus floor augmentations using phycogenic hydroxyapatite combined with autologous bone collected at the augmentation site and venous blood were performed on 18 patients aged 57.4 +/- 12.5 years (mean +/- SD) with severe atrophy of the posterior maxilla. Graft volume was measured 1 to 14 days postoperatively and before the placement of dental implants 6.1 +/- 2.1 months later (mean +/- SD; range, 4 to 11 months) to evaluate the amount of time-dependent resorption of the implanted material on computerized tomographic (CT) images of the augmented region. The images were put into Digital Imaging and Communications in Medicine (DICOM) format and evaluated using the software library Analyze. The implanted bone replacement material was plotted manually on each CT slice, and the volume of the implanted material was calculated. RESULTS: The average volume loss of the bone replacement material during the observation period was 13.9% +/- 1.9% (mean +/- SEM). All sinus floor augmentations healed without complications except for delayed membrane exposure in 2 cases. DISCUSSION: The results indicate that the graft material, a mixture of Algipore, bone chips from the access area, and venous blood, exhibited a small volume loss over a period of approximately 6 months, thus providing predictable height for second-stage implant surgery. CONCLUSION: Further investigations are needed to evaluate long-term stability and implant success.     

Cardiac arrest in dental offices. Report of six cases

The extreme medical emergency situation in the dental setting is cardiac arrest. The need to provide dental treatment to the medically compromised patients, suffering from very high risk heart diseases at special oral medicine hospital dentistry units, expose the dental and medical teams to the possibility of patients' death. Cardiac and cardiorespiratory arrest in these units faces the dentists with the need to perform basic and/or advanced cardiopulmonary resuscitation (CPR). Various etiologies are responsible for cardiac arrests. This article describes our experience and the outcome of six patients who have suffered cardiac arrests pre, during or post dental treatment in two special oral medicine centers. Two patients, suffering from severe congestive heart failure experienced fatal ventricular arrhythmia, both of them underwent CPR with early cardiac defibrillation, following which one patient completely recovered, and the other one expired. Two young and healthy patients experienced severe neurocardiogenic syncope with heart standstill for more than 40 seconds followed by spontaneous uneventful recovery. The fifth patient, who suffered from ventricular fibrillation as a result of an acute coronary ischemia, was resuscitated successfully. The last patient, a young woman, suffered from a severe status epilepticus causing bradycardia, which led to cardiac arrest, but recovered following CPR. All patients who did not recover spontaneously underwent methodical advanced CPR with early defibrillation. Only one patient out of the six died.     

Serious cerebral complications following unilateral ligation of the internal jugular vein. Review of the literature and a case report.

Serious intracranial sequelae of unilateral internal jugular vein ligation or resection are extremely rare. 22 cases including our own, were found in the literature, eight of them with a fatal outcome. Factors involved such as abnormalities of the cerebral venous sinus system, controlled hypotension, hypovolemia, posture, and dressings are discussed, as well as safeguards and possible preoperative diagnostic measures.     

Effects of isoflurane on parasympathetic vasodilatation in the rat submandibular gland

Volatile anesthetics have been known to suppress parasympathetic reflex vasodilatation in the lower lip and palate. However, in the submandibular gland, little is known about the effects of these anesthetics on the parasympathetic vasodilatation elicited by reflex and direct (i.e., non-reflex) activation of the parasympathetic vasodilator mechanisms. Although both parasympathetic vasodilatations were inhibited by isoflurane in a concentration- and time-dependent manner, the effects of continuous administration of the alpha(1)-adrenoceptor agonist methoxamine were markedly different: The reflex vasodilatation was not affected by methoxamine, while the direct vasodilatation was significantly reduced. Picrotoxin (GABA(A) receptor antagonist) attenuated the inhibitory effect of isoflurane on direct vasodilatation and the systemic arterial blood pressure. These findings suggest that the isoflurane-induced inhibitory effects on direct vasodilatation are produced by a decrease of peripheral vascular tone by GABAergic mechanisms, whereas those on the reflex vasodilatation are produced exclusively by the inhibition of the reflex center.