Isoflurane alone versus small dose propofol with isoflurane for removal of laryngeal mask airway in children-a randomized controlled trial.

OBJECTIVE: To compare the safety of laryngeal mask airway removal using two different deep anaesthesia techniques in paediatric patients. METHODS: The Randomized Control Trial was conducted at Aga Khan University Hospital, Karachi, from April 2012 to November 2013, and comprised patients aged 2-10 years scheduled for infraumbilical surgeries. Anaesthesia was induced with sevoflurane and later it was maintained by is oflurane, oxygen and nitrous oxide. The laryngeal mask airway was removed in the intervention group-I at 0.4 minimum alveolar concentration of isoflurane with propofol 1mg/kg. In the control group-II, it was removed at 1.2 minimum alveolar concentration of isoflurane alone. SPSS 19 was used for data analysis. RESULTS: Of the 50 patients, there were 25(50%) in each of the two groups. Overall, there were 46(92%) males and 4(8%) females. Incidence of airway obstruction and teeth clenching was significantly higher in group-II (p<0.05 each). Emergence duration was also significantly increased in group-II compared to group-I (p=0.001). The Post-Anaesthesia Care Unit stay timing was not significantly different between the groups (p=0.74). CONCLUSIONS: Laryngeal mask airway removal under deep anaesthetic technique of low-dose propofol with isoflurane was found to be associated with minimal adverse airway events than isoflurane alone in paediatric patients.

Use of Volatile Anesthetic Agent in Extracorporeal Circuit as a Cause of Break in Polycarbonate Connector-Lessons Learnt.

Mishaps, near misses, and lethal incidents are known to occur during cardiopulmonary bypass. We share one such rare case of break in polycarbonate connector because of the use of isoflurane in extracorporeal circuit and its successful management.

Emergence agitation after orthognathic surgery: a randomised controlled comparison between sevoflurane and desflurane.

BACKGROUND: This study aimed to compare emergence agitation following sevoflurane and desflurane anaesthesia in adults undergoing orthognathic surgery. The hypothesis was that there might be a difference in the incidence of emergence agitation following sevoflurane and desflurane anaesthesia considering the difference in blood solubility and speed of recovery between the two. METHODS: In this prospective randomised double-blind study, 144 adults undergoing orthognathic surgery were randomly allocated to either sevoflurane or desflurane anaesthesia. The incidence of emergence agitation and possible causative factors were then compared between the groups. RESULTS: The incidence of emergence agitation was lower in the desflurane group than in the sevoflurane group (24% vs. 71%, P < 0.001). In addition, the time intervals between the discontinuation of anaesthetics and the first response, extubation, and discharge from post-anaesthesia care unit were significantly shorter in the desflurane group (P = 0.002, P < 0.001 and P = 0.003, respectively). The other variables were similar in the two groups. CONCLUSIONS: In adults undergoing orthognathic surgery, desflurane anaesthesia was associated with less emergence agitation than was sevoflurane anaesthesia.

Intraoperative Blood Loss During Orthognathic Surgery: A Comparison of Remifentanil-Based Anesthesia With Sevoflurane or Isoflurane.

PURPOSE: The aim of the present study was to compare the blood loss with remifentanil-based anesthesia with sevoflurane or isoflurane during orthognathic surgery. PATIENTS AND METHODS: In this randomized controlled clinical trial, the patients who were scheduled for orthognathic surgery were divided into 2 groups: the sevoflurane (Sevo) group and isoflurane (Iso) group. Anesthesia was maintained using end-tidal concentrations of 1.4% sevoflurane or 0.9% isoflurane. Remifentanil was continuously infused at 0.05 to 0.5 µg/kg/min to maintain the mean blood pressure (MBP) at 60 to 65 mm Hg. The intraoperative blood loss was compared between the 2 groups. The Student t test for unpaired samples was used for statistical analysis. P < .05 was considered statistically significant. RESULTS: The study sample included 19 men and 45 women (n = 64). The mean age was 25 years (range 16 to 50). The intraoperative blood loss tended to be greater in the Iso group (n = 32; 4.79 ± 3.22 mL/kg) than in the Sevo group (n = 32; 4.00 ± 1.98 mL/kg). However, the difference between the 2 groups was not significant. CONCLUSION: In a comparison of intraoperative blood loss during remifentanil-based anesthesia with sevoflurane or isoflurane during orthognathic surgery, no difference was observed between the 2 groups.

Children's cognitive recovery after day-case general anesthesia: a randomized trial of propofol or isoflurane for dental procedures.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is well established in adults but has been underinvestigated in children. As day-case procedures are increasingly common, it is important to establish whether children suffer significant POCD. Pediatric POCD has been associated with several intravenous and inhalation anesthetics, but isoflurane has not been studied. As evidence indicates superior recovery after propofol, the study compared POCD after propofol or isoflurane anesthesia. OBJECTIVES: To compare the effects of propofol versus isoflurane upon children's POCD. METHODS: Fifty-eight children aged 5-14 years were randomized to propofol (total intravenous anesthesia) or isoflurane for day-case dental procedures. Reaction time (RT), verbal and visual memory, psychomotor coordination, and attention were assessed preoperatively, prior to discharge and at 24 h. RESULTS: Reaction time and psychomotor control were impaired postoperatively in both groups but recovered at 24 h. Delayed verbal recall was significantly impaired only after propofol. Both groups had significant impairment of visual memory postoperatively and at 24 h, and of recognition memory postoperatively only. CONCLUSIONS: Propofol and isoflurane exert similar adverse effects on RT, psychomotor coordination, and visual memory. Selective impairment of verbal recall by propofol is consistent with adult evidence of the drug's effect on retrieval. The enduring postoperative impairment of memory has implications for instructions to parents and caregivers for the safety and well-being of children in the 24 h after day-case anesthesia with propofol and isoflurane.

Comparison of the effect of 2 hypotensive anesthetic techniques on early recovery complications after orthognathic surgery.

The aim of this study was to evaluate the recovery complications following the use of 2 anesthetic protocols in orthognathic surgery, namely, propofol with remifentanil and isoflurane with remifentanil. Sixty-two patients with American Society of Anesthesiologists physical status I were selected. All underwent bimaxillary orthognathic surgery. Propofol with remifentanil was used as an anesthesia in group 1 (n = 32), and isoflurane with remifentanil was used in the patients in group 2 (n = 30). Early recovery complications consisting of pain, postoperative nausea and vomiting (PONV), shivering, and agitation were evaluated and documented. The length of the operation and duration of recovery were documented for all patients. Analysis of the data demonstrated no relationship between age and recovery time (P > 0.05). Analysis of data with χ(2) and independent t-tests did not show any difference between the 2 groups with regard to pain, agitation, PONV, and shivering (P > 0.05). Logistic regression was used to evaluate the effect of the operation time on recovery complications. The analysis showed that pain and PONV were significantly higher in those who experienced a longer operation time. With increasing operation time longer than 165 minutes, 64% of patients experienced pain, and 89% of them had PONV. General anesthesia can be provided via intravenously administered medications and/or inhaled volatile anesthetics. No significant difference in early recovery time was found in patients when either isoflurane or propofol was used to maintain the anesthesia. However, the length of the operation played a major role in increasing early recovery complications.

Transient postoperative glycosuria after isoflurane exposure in two dogs.

The present report describes two surgical cases involving the development of sudden glycosuria after isoflurane anaesthesia, despite the dogs having normal blood glucose levels and renal glucose reabsorption. The glycosuria manifested 1 day after surgery and resolved spontaneously within 2 days in both cases. Considering that the surgeries (subcutaneous mandibular mass removal and fracture repair) were unrelated to the kidneys, and there were no remarkable events during anaesthesia, the glycosuria may have been associated with the isoflurane anaesthesia. There have been several previous reports of glycosuria in human patients following transient proximal tubule dysfunction due to volatile anaesthetics. This case report suggests the possibility of transient renal dysfunction following isoflurane anaesthesia in these two clinically healthy dogs. However, considering the observational nature of this report, it can not be excluded that any other procedure performed in these animals was responsible of the observed glycosuria.

Isoflurane increases cell membrane fluidity significantly at clinical concentrations.

There is an on-going debate whether anesthetic drugs, such as isoflurane, can cause meaningful structural changes in cell membranes at clinical concentrations. In this study, the effects of isoflurane on lipid membrane fluidity were investigated using fluorescence anisotropy and spectroscopy. In order to get a complete picture, four very different membrane systems (erythrocyte ghosts, a 5-lipid mixture that mimics brain endothelial cell membrane, POPC/Chol, and pure DPPC) were selected for the study. In all four systems, we found that fluorescence anisotropies of DPH-PC, nile-red, and TMA-DPH decrease significantly at the isoflurane concentrations of 1 mM and 5 mM. Furthermore, the excimer/monomer (E/M) ratio of dipyrene-PC jumps immediately after the addition of isoflurane. We found that isoflurane is quite effective to loosen up highly ordered lipid domains with saturated lipids. Interestingly, 1 mM isoflurane causes a larger decrease of nile-red fluorescence anisotropy in erythrocyte ghosts than 52.2 mM of ethanol, which is three times the legal limit of blood alcohol level. Our results paint a consistent picture that isoflurane at clinical concentrations causes significant and immediate increase of membrane fluidity in a wide range of membrane systems.

The impact of the anesthetic conserving device on occupational exposure to isoflurane among intensive care healthcare professionals.

BACKGROUND: Use of anesthetic conserving devices (ACD) for inhalational isoflurane sedation in Intensive Care Units (ICU) has grown in recent years, and healthcare professionals are concerned about isoflurane pollution and exposure-related health risks. Real-time measurements to determine isoflurane exposure in ICU personnel during short-term patient care procedures and ACD handling have not yet been performed. METHODS: Isoflurane concentrations in the breathing zones of ICU staff (25 cm around the nose and mouth) were measured, by photoacoustic gas monitoring, during daily practice including tracheal suctioning, oral hygiene, body care, and patient positioning. Isoflurane pollution was further determined during ACD replacement, syringe filling, and after isoflurane spillages. RESULTS: The average mean isoflurane concentration 25 cm above patients' tracheostoma was 0.3 ppm. Mean (cmean) and maximum (cmax) isoflurane exposure in personnel's breathing zones during patient care ranged from 0.4 to 1.9 ppm and 0.7 to 6.6 ppm, respectively. Isoflurane exposure during ACD replacement was cmean 0.5 to 17.4 ppm and cmax 0.8 to 114.3 ppm. Isoflurane concentrations during ACD syringe filling ranged from 2.4 to 9.1 ppm. The maximum isoflurane concentrations after spillage were dose-dependent. CONCLUSIONS: Use of ACDs and patient physical manipulation are accompanied by isoflurane pollution. Baseline concentrations did not exceed long-term exposure limits, but short-term limits were occasionally exceeded during patient care procedures and ACD handling. Spillages should be avoided, especially when air-conditioning and scavenging systems are unavailable.

Occurrence of adenylate kinase in cerebrospinal fluid after isoflurane anaesthesia and orthognathic surgery.

UNLABELLED: The study objective was, firstly, to investigate whether anaesthesia with induced arterial hypotension would cause leakage of a biochemical marker of neuronal injury, adenylate kinase (AK), into the cerebrospinal fluid (CSF). ( DEFINITION: arterial hypotension = mean arterial pressure (MAP) 50-65 mmHg during > or = 10 min). Secondly, a subgroup of patients was examined with a limited battery of psychometric tests. Patients, scheduled for orthognathic surgery, were allocated to either hypotension (n = 20) or normotension (n = 20). Seventeen patients were subjected to psychometry. Arterial blood pressure was recorded continuously and controlled by adjustments of the administered concentration of the inhalational anaesthetic isoflurane. Fentanyl, an opioid, was given equally in both groups. A lumbar puncture was performed approximately 20 h post-operatively for a CSF sample, later analysed for AK activity. Neuropsychological tests were performed the day before surgery and the fourteenth day postoperatively. The CSF-AK value was pathologically increased ( > 0.040 U/L) in 24 patients (65%), of whom 9 were normotensive. There was no significant difference between the CSF-AK values in the hypotensive and normotensive groups, mean values were 0.082 (s.d. 0.051) and 0.066 (s.d. 0.059) U/L, respectively. The overall correlation between the 10 min MAP levels and the CSF-AK values was close to zero. In the pilot neuropsychological investigation some abnormalities were observed, indicating clinically significant adverse effects in four hypotensive patients, of whom two displayed pathologically increased CSF-AK values. At the group level, the correlation between the changes in psychometry and the measured CSF-AK values was poor. Increases in CSF-AK activities may be a non-specific occurrence in the perioperative interval, possibly indicating an adverse effect on the brain. Arterial hypotension could not be proven to explain the CSF-AK outcome.

Evidence of cerebral dysfunction associated with isoflurane- or propofol based anaesthesia for orthognathic surgery, as assessed by biochemical and neuropsychological methods.

A relationship has previously been described between individual mean isoflurane concentrations and the release of a marker of neuronal injury, adenylate kinase (AK), into the cerebrospinal fluid (CSF) after anaesthesia and orthognathic surgery. Likewise, reduced mental performance has been detected. Twenty-nine patients scheduled for orthognathic surgery were assigned to isoflurane- or propofol based anaesthesia, which was adjusted to a defined level with the aid of processed EEG and quantitative surface EMG. In the case of a mean arterial pressure (MAP) < 50 mmHg a phenylephrine infusion was started to keep the MAP above the minimal level, otherwise no regard was paid to the blood pressure, which never exceeded normal values. A lumbar puncture for CSF sampling was performed approximately 20 h postoperatively. The CSF sample was analysed for AK activity. Neuropsychological tests were performed the day prior to surgery and again in the period 4-8 weeks postoperatively. Five patients were re-examined by psychometry 12-30 months later. A release of AK into CSF was confirmed, equal in both groups. Correlation with the anaesthetic dose given was poor. Five patients from each group failed significantly in the postoperative neuropsychological tests. They differed in several demographic respects from the others. When five of the failed patients were re-examined 12-30 months later, three patients still performed poorly in the tests. Biochemical and neuropsychological disturbances were recorded in several patients objected to orthognathic surgery. The underlying mechanisms are unclear, including the role of the anaesthetic drugs or surgery itself.

Propofol vs isoflurane anesthesia-incidence of PONV in patients at maxillofacial surgery.

PURPOSE: Prophylaxis of PONV (postoperative nausea and vomiting) is important for maxillofacial surgery. Vomiting is particularly unpleasant for the patient and undesirable as it may be detrimental to the operative area. The aim of this study is to compare the incidence of PONV after propofol with that after isoflurane anesthesia. MATERIALS AND METHODS: 84 patients age 15-50, ASA I-II, undergoing maxillofacial surgery were randomly allocated in two groups. Group P n=42 -using TIVA (Total Intravenous Anesthesia) with propofol and Group I n=42- using isoflurane anesthesia. The incidence and severity of PONV was evaluated for 24 hours postoperatively based on scoring system: 0=no emetic symptoms, 1=nausea, 2=vomiting. Whereas the severity of nausea was assessed using a four-point Likert scale, with 0=none, 1=mild, 2=moderate, 3=severe. RESULTS: There were no significant differences between the groups with respect to demographic data and duration of anesthesia. The incidence of nausea (2-3 Likert scale) in the propofol group was 11.9% compared to the isoflurane group 38.1% during early post-operative period (0-6 hrs) (p=0.011), whereas during late post-operative period 7.1% in group P compared with 11.9% in group I (p=0.712).Incidence of vomiting in early post-operative period in-group P was 4.8%, whereas in-group I 11.9% (p=0.432). In late postoperative period in-group P no patient suffered from vomiting or retching, whereas in-group I 4.8% (p=0.494). CONCLUSIONS: TIVA with propofol reduces the postoperative incidence of nausea and vomiting after maxillofacial surgery, compared with isoflurane anesthesia, and also reduces requirements of antiemetic medications.

Conservative treatment of Angle Class III malocclusion with anterior crossbite

Angle Class III malocclusion is characterized by anteroposterior dental discrepancy which might be associated or not with skeletal changes. Class III molar relationship is associated with vertical or lingually tipped mandibular incisors and a usually concave profile. These characteristics seriously affect facial esthetics and most frequently are the reason why patients seek orthodontic treatment. This case was presented to the committee of the Brazilian Board of Orthodontics and Facial Orthopedics (BBO) as part of the requisites to become a BBO Diplomate.

A má oclusão de Classe III de Angle é caracterizada por uma discrepância dentária anteroposterior, que pode ou não estar acompanhada por alterações esqueléticas. Observa-se uma relação molar de Classe III associada ao posicionamento vertical ou retroinclinado dos incisivos inferiores e, geralmente, perfil facial côncavo. Esse aspecto gera grande comprometimento estético na face, sendo justamente esse o fator que, na maioria das vezes, motiva o paciente a procurar pelo tratamento ortodôntico. O presente caso clínico foi apresentado à Diretoria do Board Brasileiro de Ortodontia e Ortopedia Facial (BBO) como parte dos requisitos para a obtenção do título de Diplomado pelo BBO.

Comparison of three anesthetic protocols for intraduodenal drug administration using endoscopy in rhesus monkeys (Macaca mulatta).

The purpose of this study was to evaluate 3 anesthetic protocols for intraduodenal drug administration by endoscopy in rhesus monkeys (Macaca mulatta). Anesthesia was induced using intramuscular ketamine and midazolam, isoflurane (inhalant gas), or intravenous propofol in male and female rhesus monkeys. A noninvasive dosing line was placed in the duodenum by use of endoscopy, and 50% dextrose (3 ml/kg) was administered. Blood pressure, heart rate, body temperature, and reflexes (corneal, palpebral, pharyngeal) and myorelaxation (mandibular reflex and reaction to limb manipulation) were evaluated every 5 min. To estimate intestinal absorption, glycemia was evaluated prior to dextrose administration and at 2, 5, 10, 15, 20, 30, 45, and 60 min after dosing. All 3 protocols resulted in successful induction of anesthesia. Recovery from isoflurane and propofol was significantly faster than from ketamine-midazolam. Duration of the recovery period after isoflurane was less variable than with propofol, but isoflurane produced greater hypothermia. Isoflurane and propofol resulted in predictable glucose absorption after intraduodenal dextrose administration, whereas ketamine-midazolam led to an inconsistent increase in glycemia.

[Exposure of intensive care personnel to isoflurane in long-term sedation]. / Exposition des Intensivpersonals durch Isofluran bei Langzeitsedierung.

OBJECTIVE: Isoflurane is a suitable agent to produce sedation in the intensive care unit (ICU). However, data concerning occupational exposure to isoflurane during long-term sedation are not yet available. The purpose of this study was to evaluate occupational exposure to isoflurane in the ICU. DESIGN: Trace concentrations of isoflurane were measured directly by means of photoacustic infrared spectrometry during isoflurane sedation in ten cases over a period of 24 hours. Values were obtained at four personnel-related and two leakage-related locations in an ICU chamber. RESULTS: All measured values were low, the majority under 3 ppm isoflurane at the personnel-related points. Peak concentrations up to 40 ppm were recorded for several minutes during nursing interventions. At measurement point "nearby patient's mouth" values up to 5 ppm were recorded, at location "anaesthesia machine" values ranged from 2 to 69 ppm isoflurane. CONCLUSION: We conclude that an effective high flow scavenging system, a low-leakage anaesthesia machine and an airconditioning equipment without recirculation could keep occupational exposure low. The majority of the measured values was below the NIOSH recommendation (2 ppm). All values was lower than a national state recommendation (10 ppm). Under other circumstances (e.g. without scavenging system) air pollution will be higher and therefore measurements at the working place are needed.

Incidence of arrhythmias in dental anaesthesia: a cross-over comparison of halothane and isoflurane.

Fifty patients received halothane anaesthesia during the surgical removal of 3rd molars from one side of the mouth and isoflurane during extractions on the other. Degree of surgical difficulty was matched, and end-tidal PCO2 did not differ significantly between sides. A significantly higher incidence of arrhythmias occurred during halothane, compared with isoflurane, anaesthesia. This difference occurred primarily when halothane was given for the first operated side. A clinically important feature of the stability of cardiac rhythm during isoflurane anaesthesia was demonstrated--when frequent ectopic beats occur during halothane anaesthesia, a significant decrease in the rate of premature contractions occurs within 3 min of discontinuing halothane and introducing isoflurane.

A comparison of the incidence and nature of cardiac dysrhythmias occurring during enflurane and isoflurane anaesthesia for dental surgery.

The incidence and nature of dysrhythmias with equipotent concentrations of enflurane and isoflurane during dental surgery were compared. Seventy-six Chinese patients between 17-30 years, of ASA Grade I, randomly received either enflurane or isoflurane with N2O and O2 for spontaneous ventilation during third molar extractions. The cardiac rhythm and the blood pressure were continuously monitored during the procedure. The incidence of dysrhythmias with both enflurane and isoflurane was low and the difference not statistically significant. During surgery one patient exhibited unifocal ventricular ectopics with isoflurane. Sinus tachycardia was common with both agents. No life-threatening dysrhythmias were seen with either agent and no clinically significant lowering of blood pressure occurred in association with the exhibited dysrhythmias. In this Chinese population, as in other studies, the incidence of dysrhythmias with both agents was low thus showing no difference between the races.

Comparison of the incidence and nature of cardiac arrhythmias occurring during isoflurane or halothane anaesthesia. Studies during dental surgery.

Seventy-six Chinese patients aged between 15 and 30 yr, undergoing 3rd molar extraction, were randomly allocated to two groups. One group received halothane and the other isoflurane. The incidence of arrhythmia during surgery under anaesthesia with isoflurane was significantly less than with halothane. Sinus tachycardia was a significant feature under anaesthesia with isoflurane. Under anaesthesia with halothane, the arrhythmias occurring most frequently during surgery were ventricular ectopics, the commonest being ventricular bigeminy. The frequency and nature of arrhythmias during surgery on right and left sides were similar. In three patients a slight decrease in arterial pressure was recorded in association with the arrhythmia, but on stopping the stimulus, both rhythm and arterial pressure returned to normal. The incidence of arrhythmia with halothane in the Chinese population in this study was significantly higher than that reported previously in non-Chinese patients.