Apnoeic oxygenation using transnasal humidified rapid-insufflation ventilatory exchange during rigid bronchoscopy: a report of four cases

General anaesthesia with a muscle relaxant is usually performed for rigid bronchoscopy (RB), but ventilation is challenging due to large amounts of leakage. Optiflow™ supplies 100% humidified, warmed oxygen at a rate of up to 70 l/min and this high flow rate may overcome the leakage problem. This case report describes four patients that were scheduled for RB. The lung lesions were all located below the carina, so a bronchial tube was inserted under general anaesthesia. Once a large amount of leakage was confirmed by manual ventilation, Optiflow™ was connected to the bronchial tube (flow rate, 70 l/min). All of the ports of the bronchoscopy were left open to prevent the risk of outlet obstruction. Oxygenation was well maintained with stable vital signs throughout the procedures, which took up to 34 min without airway intervention. There were no occurrences of cardiac arrhythmia or changes in the electrocardiograms. Respiratory acidosis recovered after emergence, which was confirmed by arterial blood gas analysis in all cases. Apnoeic oxygenation using Optiflow™ was applied successfully during RB. Applying Optiflow™ could make cases of difficult ventilation during RB much easier for the anaesthetist. Larger studies need to demonstrate the efficacy and safety of this technique.

DIAGNOSTIC BRONCHOSCOPY FOR EVALUATION OF CONGENITAL STRIDOR:A CASE SERIES

Introduction: Stridor is a noise mechanically produced through partially occluded airway. Airway obstruction may be extrathoracic or intrathoracic. Stridor may be congenital or acquired. Timing in respiratory cycle determines anatomic location of lesion – inspiratory, biphasic, or expiratory. Gold standard for diagnosis is bronchoscopy which requires general anaesthesia in infants and small children. Major anaesthetic concerns are – possible difficult airway, sharing of an already compromised airway, airway oedema. Case Description: 40 infants, 0 - 6 months age, with history of noisy breathing suggestive of congenital stridor, planned for diagnostic rigid bronchoscopy with or without therapeutic procedure, over one year period. Preoperative treatment – humidified oxygen, nebulization, dexamethasone, antibiotics, anti-reflux medication. Not premedicated, standard monitors applied. Induction of anaesthesia with inhalational oxygen and sevoflurane or intravenous propofol, fentanyl 1 mcg/kg, dexamethasone 0.5 mg/kg. Topical lidocaine 2% sprayed at vocal cords. 100% oxygen with propofol infusion for maintenance with spontaneous ventilation via nasopharyngeal airway. Patients requiring surgical intervention intubated using microcuffed endotracheal tube. Patients observed post-operatively. If ventilation was inadequate, intubated to control airway during recovery, extubated on restoration of spontaneous ventilation. After surgical intervention, babies shifted to ICU for elective ventilation for 48 hours. Discussion: On bronchoscopy, laryngomalacia was the finding in majority of cases. Others had subglottic stenosis, tracheomalacia, vocal-cord paresis, laryngeal cyst. Out of 40 patients, 9 underwent therapeutic procedure and were electively ventilated, 26 resumed spontaneous breathing, 2 patients had delayed recovery and 2 had severe chest retractions and desaturations and they were managed accordingly. One baby aged 6 months diagnosed with grade III subglottic stenosis desaturatedand tracheostomy had to be done. Conclusion:Anaesthesia for rigid diagnostic bronchoscopy is a significant challenge. Rigid bronchoscopy under general anaesthesia requires multidisciplinary approach and close cooperation between all team members.

Comparison of Intravenous Lignocaine and Esmolol in Attenuating Hemodynamic Response and Cough Reflex during Extubation in Hypertensive Patients under General Anaesthesia

Tracheal extubation carries higher complication rates compared to intubation during general anaesthesia (GA). Thus, various drugs are used to attenuate hemodynamic responses and cough reflex during extubation. We investigated if intravenous (IV) lignocaine and esmolol, given prior extubation, was able to achieve that in hypertensive patients under GA. In this prospective, double-blinded, randomised controlled study, 68 hypertensive patients on treatment undergoing GA were analysed. Group L received IV lignocaine 1 mg/kg while Group E received IV esmolol 1.5 mg/kg, 2 minutes before extubation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were recorded at the following interval: before study drug administration (T-0), prior extubation (T-1), 1 minute (T-2), 3 minutes (T-3), 5 minutes (T-4) and 10 minutes (T-5) post-extubation. Group L showed significantly increase in HR at T-2 while SBP and MAP increased significantly from T-1 until T-5. Group E showed a significant reduction in HR at T-1 up to T-5 and significantly lower HR at T-1 and T-2 compared to Group L. Group E showed stable SBP, DBP and MAP at all intervals. In conclusion, IV esmolol at 1.5 mg/kg was able to attenuate the hemodynamic response more pronounced when compared to IV lignocaine at 1 mg/kg from extubation stress in patients with hypertension on treatment. Both lignocaine and esmolol were equally effective in suppressing cough reflex during extubation.

The Effect of the Preoperative Fasting Regimen on the Incidence of Gastro-Oesophageal Reflux in 90 Dogs

This study aimed to investigate the effect of three different preoperative fasting regimens on the incidence of gastro-oesophageal reflux (GOR) in dogs under general anaesthesia. Ninety dogs undergoing non-abdominal and non-thoracic elective surgery were included in the study and equally allocated to three groups. Dogs received canned food providing half the daily resting energy requirements (RER) 3 h prior to premedication (group 3H), a quarter of the daily RER 3 h before premedication (group 3Q), and half the daily RER 12 h before premedication (group 12H). The animals were premedicated with acepromazine and pethidine, anaesthesia was induced with propofol and maintained with isoflurane vaporised in oxygen. Oesophageal pH was monitored throughout anaesthesia. Demographic and surgery-related parameters were not different among groups. The incidence of GOR was 11/30 in group 3H (36.7%), 9/30 in group 3Q (30.0%) and 5/30 in group 12H (16.7%), which was not statistically different (p = 0.262). Reduction of the amount of the preoperative meal from half to a quarter of the daily RER did not reduce the incidence of GOR but resulted in a lower oesophageal pH (p = 0.003). The results of this study suggest that the administration of a meal 3 h before anaesthesia does not have any beneficial effect in the reduction of GOR incidence in dogs compared to the administration of a meal 12 h before anaesthesia.

The importance of perioperative optimisation to facilitate safe regional anaesthesia and their improved outcomes in fracture neck of femur patients

Background: Hip fractures are common presentations to orthopaedic departments, and their surgical management often results in blood transfusions. Compared with general anaesthesia, regional anaesthesia reduces the need for transfusions and mortality in the wider surgical population. Aims: In hip fracture patients, our primary outcome measure was to examine any relationship between anaesthetic modality and transfusion rates. The secondary outcome measure was to assess the relationship between anaesthetic modality and one-year mortality. Methods: A retrospective cohort study of 280 patients was carried out in 2017 and 2018. Data were collected from patient records, local transfusion laboratory and the national hip fracture database. Results: A total of 59.6% had regional and 40.4% general anaesthesia. Regional anaesthesia patients were younger with fewer comorbidities (p < .05). About 19.8% regional and 34.5% general anaesthesia patients received transfusions (odds ratio (OR) = 0.47, p < .05); 13.6% were taking anticoagulants and were less likely to receive a regional anaesthetic (31.6% versus 64%, OR = 0.26, p < .05). One-year mortality was 27% for regional and 37% for general anaesthetic patients (OR = 0.64, p = .09). Conclusion: Regional anaesthesia halved the risk of blood transfusion. Anticoagulated patients were 74% less likely to receive regional anaesthetics, but had no additional transfusion risk. With optimisation, a larger proportion of patients could have regional anaesthesia.

Comparative Study of Safety and Efficacy of Three Different Doses of Fentanyl on Hemodynamic Response to Laryngoscopy and Tracheal Intubation in Patients under General Anaesthesia

Aim of Study: Laryngoscopy and endotracheal intubation are the commonest method for securing a definitive airway for general anaesthesia. It is one of the most invasive and painful stimuli in anaesthesia producing clinically relevant changes in the hemodynamic variables. This study has been designed to compare the safety and efficacy of three different doses of fentanyl (2µg/kg, 3µg/kg and 4µg/kg) in attenuating hemodynamic response, following laryngoscopy and endotracheal intubation. Materials and Methods: In this observational study, three groups of 90 patients belonging to ASA grade I and II, aged between 18 to 65 years, including either gender, posted for elective surgery under GA with informed consent. Baseline vital hemodynamic parameters and the serial heart rate, arterial pressures, SpO2 and respiratory rate were noted at five minutes after intravenous fentanyl administration, during laryngoscopy & intubation and at 1-, 3-, 5-, 10- and 20-minutes after laryngoscopy. Ramsay sedation scores were also noted at five minutes after intravenous fentanyl administration, during extubation and at 10-, 20- and 30-minutes after extubation. Results: There was substantial difference in mean HR, SBP, DBP & MAP values post 5 minutes after intravenous fentanyl administration, during laryngoscopy, at 1, 3-, 5-, 10- and 20-minutes following laryngoscopy and intubation between the three groups. Patients’ behaviour belonging to group C (IV fentanyl 4µg/kg), followed by the patients of group B (IV fentanyl 3µg/kg) presented considerable amount of attenuation of all the hemodynamic stress parameters effectively, with statistically significant results when compared to group A (IV fentanyl 2µg/kg). Conclusion: Intravenous fentanyl 4µg/kg and 3µg/kg are better at attenuating the laryngo-tracheal stress response, in comparison to intravenous fentanyl 2µg/kg.

Haemato-biochemical and blood gas changes in bovines under multimodal anaesthesia

The study was conducted in six crossbred female cattle aged nine months to five years and weighing between 82-375 kg, to evaluate haematobiochemical and blood gas changes in during multimodal general anaesthesia. The animals were premedicated by intravenous administration of butorphanol (0.05mg/kg body weight) immediately followed by xylazine (0.02 mg/kg body weight). On achieving sedation, the animals were controlled in left lateral recumbency and induction of anaesthesia was carried out by intravenous administration of ketamine and midazolam at the dose rate of 4.0 and 0.2 mg/kg body weight respectively. Endotracheal intubation was performed and maintenance of general anaesthesia was carried out using isoflurane in 100% oxygen. The variation in total erythrocyte count, total leukocyte count, volume of packed red cells, platelet count and haemoglobin were non-significant before and after anaesthesia. A non-significant lymphocytopaenia with neutrophilia and mild variations in aspartate aminotransferase and alanine aminotransferase enzyme levels were also noticed. Blood pH reduced significantly (p<0.05) after induction of anaesthesia and returned to baseline values after recovery whereas PvCO2 (p<0.05) and base excess (p<0.01) values increased significantly after induction of anaesthesia. The blood bicarbonate did not alter significantly following induction of anaesthesia.

Characterisation of Children's Head Motion for Magnetic Resonance Imaging With and Without General Anaesthesia

Head motion is one of the major reasons for artefacts in Magnetic Resonance Imaging (MRI), which is especially challenging for children who are often intimidated by the dimensions of the MR scanner. In order to optimise the MRI acquisition for children in the clinical setting, insights into children's motion patterns are essential. In this work, we analyse motion data from 61 paediatric patients. We compare structural MRI data of children imaged with and without general anaesthesia (GA), all scanned using the same hybrid PET/MR scanner. We analyse several metrics of motion based on the displacement relative to a reference, decompose the transformation matrix into translation and rotation, as well as investigate whether different regions in the brain are affected differently by the children's motion. Head motion for children without GA was significantly higher, with a median of the mean displacements of 2.19 ± 0.93 mm (median ± standard deviation) during 41.7±7.5 min scans; however, even anaesthetised children showed residual head motion (mean displacement of 1.12±0.35 mm). For both patient groups translation along the z-axis (along the scanner bore) was significantly larger in absolute terms (GA / no GA: 0.87±0.29/0.92 ± 0.49 mm) compared to the other directions. Considering directionality, both patient groups were moving in negative z-direction and thus, out of the scanner. The awake children additionally showed significantly more nodding rotation (0.33±0.20°). In future studies as well as in the clinical setting, these predominant types of motion need to be taken into consideration to limit artefacts and reduce re-scans due to poor image quality.