Background: One lung ventilation (OLV) results in a ventilation-perfusion (V/Q) mismatch. Protective lung ventilation (PLV) reduces postoperative pulmonary complications following OLV. However, PLV predisposes to areas of atelectasis in the ventilated lung and worsens the V/Q mismatch. Aim of Study: To evaluate the gradient between arterial carbon dioxide tension (PaCO₂) and partial pressure of end-tidal carbon dioxide gas (ETCO₂) during OLV using PLV. The second objective was to see if a high gradient could be predicted based on preoperative pulmonary function tests (PFTs), American Society of Anesthesiologists Physical Status (ASA-PS) or intraoperative haemodynamic changes. Patients and Methods: The PaCO₂ and ETCO₂ during two lung ventilation (TLV) and OLV were noted with patient in the lateral position. The PaCO₂-ETCO₂ gradients during TLV and OLV were calculated. The mean values of PaCO₂, ETCO₂ and PaCO₂-ETCO₂ gradient were compared for OLV and TLV. For gradients above 8 mm Hg, PFT, ASA-PS grade and blood pressure were assessed to identify any clinical association. Results: Sixty patients were enrolled in the study. The mean values of PaCO₂ were 38.17 and 44.02 mm Hg during TLV and OLV respectively. The mean values of ETCO₂ were 31.31 and 34.53 mm Hg during TLV and OLV respectively. The mean PaCO₂-ETCO₂ gradient was 6.74 and 9.71 mm Hg during TLV and OLV respectively. These values were significantly lower during TLV than OLV. Conclusion: ETCO₂ does not correspond with PaCO₂ during OLV using PLV. It is not possible to predict which patients will show a higher PaCO₂-ETCO₂ gradient. This study could not find any clinical association between the preoperative PFT, ASA-PS grade or intraoperative haemodynamics when PaCO₂-ETCO₂ gradient was greater than 8 mm Hg.

Background: Ambu^® AuraGain™ laryngeal airway is a supraglottic airway device designed to provide better airway protection and airway seal pressures. Aim of Study: To quantify oropharyngeal leak pressures (OPLPs), fibreoptic view, peak airway pressure and ventilation scoring with Ambu^® AuraGain™ in children in different head and neck positions such as maximum flexion, maximum extension and lateral rotation. Patients and Methods: Sixty-eight children aged between 1 and 6 years posted for surgery were enrolled. Ambu^® AuraGain™ was inserted after the induction of anaesthesia and ventilation was confirmed. OPLP, fibreoptic view, peak airway pressure and ventilation scores were noted in different head and neck positions such as maximum flexion, maximum extension and lateral rotation. Results: The OPLP significantly increased in flexion (P < 0.001) and significantly decreased in extension (P < 0.001) when compared to the neutral position. Airway pressure (Paw) increased significantly in flexion (P < 0.001) and decreased in extension (P = 0.04) when compared to the neutral position. Tidal volume delivery was comparable in all positions. There was a statistically significant decrease in ventilation scoring in the flexed position when compared to the neutral position (P = 0.005). There was a significant worsening of fibreoptic view in flexion when compared to the neutral position (P < 0.001). Fibreoptic view in the lateral position and extension was comparable with the neutral position. Conclusions: Use of Ambu^® AuraGain™ laryngeal airway provides the best ventilatory parameters and Paw in children with head in the neutral and lateral position but lower OPLP with head in extension. However, flexing the head results in the worst ventilatory parameters and Paw among the positions studied.

Background: Maintenance of airway patency and oxygenation are the main objectives of face mask ventilation. Preoperative prediction can reduce the incidence of unanticipated difficult mask ventilation (DMV). Aim of Study: The aim of this study was to evaluate the correlation between predictors of DMV and its grading using a risk score. Study Setting and Design: This was an observational study approved by the Institutional Ethics Committee in a tertiary care hospital between 2020 and 2021. Patients and Methods: A total of 110 adult patients scheduled for elective surgery under general anaesthesia were studied. A detailed preoperative airway assessment was done to identify and risk score for seven standard predictors of DMV (male gender, age >55 years, body mass index ≥30 kg/m², obstructive sleep apnoea [STOP-BANG score], edentulous state, modified Mallampati class and presence of beard). The risk score was correlated with the grading of mask ventilation in the operation theatre performed using the four-point scale as described by Han et al. Results: A statistically significant association was found with standard predictors such as male gender, obstructive sleep apnoea (STOP-BANG score) and the total preoperative risk score with the grading of mask ventilation (P < 0.05 for all). Additional risk factors found statistically significant were interincisor distance, thyromental distance, neck circumference, receding mandible, mandibular jaw protrusion, restricted neck movements, buck teeth and submucosal fibrosis. Conclusion: Prediction of DMV with preoperative risk score can lead to better anticipation of difficult airway management. Appropriate anticipatory airway management could potentially decrease the incidence of failed ventilation and resultant hypoxia.

Fibreoptic bronchoscopy-guided intubation (FOBI) is ideal in establishing the airway in patients with anticipated difficult airway before the induction of general anaesthesia. At times, patient factors lead to the need for FOBI in unconventional positions. We encountered a patient with postburn contracture with fixed flexion deformity of the neck who was unable to lie supine. Awake FOBI in sitting position turned out to be the ideal position for our patient.

Flexible videobronchoscopy-guided awake intubation is the standard of care in adult patients with negligible mouth opening presenting for corrective surgeries. Although paediatric and neonatal flexible bronchoscopes are available, they are seldom used for awake intubation due to a lack of cooperation from children. A highly sensitive airway coupled with an increased risk for bronchospasm in children precludes attempts in performing bronchoscopy without any sedation. As a result, elective tracheostomy is often performed in such children with anticipated difficult airways. Our report describes the rationale, procedure and implications of videobronchoscopy-guided nasotracheal intubation under conscious sedation in a 5-year-old child with Treacher Collins syndrome or mandibulofacial dysostosis complicated by obstructive sleep apnoea.

Intraoperative motor evoked potentials are being increasingly used in surgeries for the removal of spinal tumours. However, this useful monitoring is accompanied by risks such as bite injury to the tongue and oral mucosal soft tissues due to clenching of the teeth and jaws as the patient may not be completely under the effect of neuromuscular blocking agents, resulting in bleeding in the oropharynx. To prevent these complications, we conceptualised and utilised a boxer's mouthguard as a preventive protection during cervical intramedullary tumour excision surgery. Such mouthguards are routinely used in contact sports such as boxing but their clinical application in neuroanaesthesia has not been described. This use is a novel, economical, convenient, standardised and easy way of bite protection and preventing intraoperative tongue, soft-tissue injuries and airway complications.

Airway management in a burn victim poses special challenges for the anaesthesiologist not only during the acute phase but also after delayed consequences have set in resulting in difficulty in airway management. We report a 5-year-old boy who was admitted to the Department of Paediatrics with biphasic stridor 2 months following inhalational burn injury. He presented with complaints of difficulty in swallowing solid food, hoarseness of voice for the past 1 month and occasional difficulty in breathing for the past 10 days. Laryngoscopy using a #2 Macintosh blade revealed pharyngeal stenosis with grossly distorted airway anatomy. The patient was finally intubated after great difficulty with a 3.5 mm internal diameter endotracheal tube using a fibrescope.