Clinical trials on the use of mechanical ventilation in Acute Respiratory Distress Syndrome (ARDS) showed that use of low tidal volumes reduces the mortality significantly. Another approach that proved beneficial was to open the lung and keep it open. Theoretically, this can be best achieved with High Frequency Oscillatory Ventilation (HFOV). HFOV provides oscillations at three to ten Hertz in adults. Both inspiration and expiration are active. Gas exchange occurs even though the tidal volume delivered during each oscillation is less than the anatomical dead space. Furthermore, the potential adverse effects of the conventional ventilation such as alveolar overdistension, and repeated opening and collapse of alveoli are reduced. Many investigators have studied the potential benefit of HFOV in neonatal and paediatric population but the evidence for its use in adult population is limited. A lot of work is being done and two large ongoing trials OSCAR and OSCILLATE should give better idea regarding its use in adults. This review article mainly focuses on the principles and practices of HFOV in adults and current evidence regarding its use in adults.

Tracheostomy is a commonly performed procedure in the intensive care unit. Selection of patients for this procedure should be done carefully after understanding the individual risks and benefits. Optimal care begins with the selection of an appropriate tube for the patient from the wide range of tubes available today. Care of the cuff, proper patient positioning, humidification of inspired gases and a well secured tube would avoid undue complications. Adequate support needs to be given to facilitate communication and swallowing. Emergency equipment for tube change should be readily available. A good tracheostomy care plan also includes oral hygiene, infection control practices, wound care and provision of adequate nutrition. Decannulation may fail, if performed without proper assessment of functional and anatomical changes in the airway. A good understanding of the basic principles of respiratory care will provide better outcome in patients with a tracheostomy.

Background: LTS II and PLMA are supraglottic devices that may be used for ventilation in patients with normal as well as difficult airways at risk of aspiration. Aim: Comparison of LTS II with PLMA during controlled ventilation in paralysed patients with respect to time to successful insertion, success rate of insertion, attempts at repositioning, airway leak pressure, ease of ventilation and Ryle's tube insertion, fibreoptic laryngeal view and complications. Methods: Thirty patients were studied using a prospective, randomised cross-over design. Ethical committee clearance and informed consent were obtained from all patients. Anaesthesia was induced with propofol and fentanyl and neuromuscular blockade achieved with vecuronium. Patients were divided into two groups: Group LTS and Group PLMA. In each group, the first airway device was inserted, various parameters observed and then removed. The second airway device was then inserted and the same parameters noted. Anaesthesia was continued with the second device in position. Results: Success with insertion at first attempt and time to insertion were comparable with both devices [LTS II 27/30 (17.5 s) and PLMA 29/30 (15.5 s) respectively]. PLMA required repositioning in fewer patients and provided better fibreoptic view than LTS II. Ryle's tube insertion failed in four patients with PLMA but in none with LTS II. No significant difference was found in the airway seal pressure [mean, PLMA (27 cm H2O) and LTS II (26.4 cm H2O)], ease of ventilation or overall complications. Conclusion: Insertion and ventilation are comparable with PLMA and LTS II. Ryle's tube insertion is easier with LTS II but requires more repositioning attempts and does not provide a good view of the larynx.

Background: Rapid sequence intubation with application of cricoid pressure is widely practiced in all emergency situations to prevent aspiration of gastric contents. Stylet or gum elastic bougie is used as intubation aid for rapidly securing the airway. Aim: To compare gum elastic bougie and malleable stylet as aids for endotracheal intubation during application of cricoid pressure. Results: Endotracheal intubation was successful in the first attempt in all of the 60 patients enrolled in the study. Time taken for laryngoscopy and intubation was clinically similar in both the groups of patients. However, in the stylet group, successful ET intubation was achieved in about 7 sec less when compared to the bougie group (p< 0.05). Ease of intubation as compared using the Visual Analogue Scale (VAS) Score was similar in both groups. Laryngeal view improved in 22 patients of 60 patients (36.66%) after application of cricoid pressure, while it remained the same as before in 22. Overall, the grade remained the same or improved after cricoid pressure in 73.3% of patients. The laryngeal view worsened in 16 patients (27.7%). Conclusion: Gum elastic bougie and stylet are equally effective intubation aids during rapid sequence intubation. Intubation aided by bougie takes more time than that of a stylet, even though it is clinically trivial. Cricoid pressure does not affect the laryngoscopic visualisation of glottis in majority of patients.

Background: Noninvasive ventilation (NIV) has been used in preterm neonates in the past few decades, with the main objective of reducing the exposure to invasive ventilation. It proves to be safe and effective but the best option is yet to be determined. Objective: To determine, if nasal intermittent positive pressure ventilation (NIPPV) decreases the need for mechanical ventilation in the first 48 h when given as a respiratory support post-extubation in preterm neonates compared to nasal continuous positive airway pressure (NCPAP). It is a randomised controlled trial. Method: Preterm neonates (gestational age 28-36 weeks) with respiratory distress requiring invasive ventilation were randomly assigned to receive NIPPV or NCPAP as postextubation respiratory support. The primary outcome was the need for mechanical ventilation within the first 48 hours of life. Results: A total of 32 neonates in postextubation NIV group after stratification to gestational age of 28-32 weeks and 33-36 weeks. The need for invasive mechanical ventilation in the first 48 h was not different in both NIPPV (11.1%) and NCPAP (7.1%). The complications associated with these modes were also compared and analysed. There was no difference noted. Conclusions: NIPPV did not decrease the need for mechanical ventilation compared to NCPAP, overall, in the first 48 hours of support. It could be considered as safe and beneficial compared to NCPAP. However, further studies have to assess the potential benefits and complications associated with NIPPV in preterm neonates.

Introduction: Many weaning indices have been proposed to evaluate readiness of a patient to tolerate discontinuation of mechanical ventilation. Aim: This study evaluated the utility of these indices in progressive weaning from mechanical ventilation. Methods: All patients receiving mechanical ventilation and assessed to be ready to wean clinically were included in the study. They were initially placed on pressure support, positive end expiratory pressure (PEEP) of 5-8 cm H₂O and FiO₂ 0.4. Tidal volume, respiratory frequency, minute ventilation and rapid shallow breathing index (RSBI) were measured at baseline, 5 min, 30 min and at 2 h. The patient was also monitored for clinical signs of respiratory distress. If the patient remained stable, the pressure support was reduced by 2 cm H₂O and the weaning process repeated till PSV reached 5-8 cm H₂O. Results: Respiratory rate (< 35/min) and tidal volume corrected to weight (> 5 mL/kg) had high sensitivity (100% and 98.5% respectively) but lacked specificity. Minute volume of < 10 L/min lacked both sensitivity (73.1%) and specificity (50%). The RSBI (< 105 b/min/L) had very high sensitivity (99.1%), reasonable specificity (83.3%) with a positive predictive value 98.4% and a negative predictive value 90.9%. RSBI corrected to weight (7 breaths/min/mL/kg) was not useful. RSBI rate of < 20% was found to be a good weaning index even for progressive decrease in ventilatory support. Conclusion: RSBI < 105 b/min/L and RSBI rate < 20% are reliable criteria to predict success of progressive weaning from mechanical ventilation using pressure support.

Background: Paediatric patients undergoing cardiac surgery are likely to be prone to developing postextubation stridor (PES) due to their airway anatomy and several factors related to surgery, Aim: To examine the incidence and risk factors for PES in paediatric patients undergoing cardiac surgery. Methods: The study was prospectively conducted in the paediatric cardiac postsurgical ICU (PICU) at a tertiary referral hospital from November 2010 to January 2012. All paediatric patients presenting with immediate stridor or its developing within 24 hours after extubation were included. Only those patients who were ventilated for at least 6 hours after surgery, but not more than 7 days and deemed fit for elective extubation were considered. Results: Of the 1328 patients admitted to the PICU, 29 patients (2.18%) met the criteria for PES. Of these, 22 (75.6%) were < 1 year old. Ten patients (34%) did not respond to conservative approach or Noninvasive Ventilation (NIV) and had to be reintubated. Six patients were reintubated within an hour, three in < 6 hours and one after 12 hours of extubation. Conclusion: PES is common in paediatric postcardiac surgical patients. Infants are more prone to develop PES. Majority of them can be successfully managed with conservative measures and noninvasive ventilation. The onset of PES varies from immediately after extubation to 3 hours after extubation. Up to one-third of the patients with PES may require reintubation and is common in the first hour after extubation. Patients who develop PES need close observation in the first few hours after extubation.

Introduction: Quantification of physiological dead space (VDphys) provides important insight into the efficiency of ventilation and its relation to pulmonary perfusion. Arterial to end-tidal carbon dioxide difference [P(a-ET)CO₂] may provide a valuable surrogate measure of VDphys and may be useful as an index of weaning success. Aim: To evaluate the utility of [P(a-ET)CO₂] as a weaning index. Methods: This prospective study enrolled 52 invasively mechanically ventilated adult patients treated in Medical Intensive Care Unit (MICU) between December 2010 and December 2011. The end-tidal carbon dioxide concentration was measured using a side stream capnograph at each attempt at decreasing ventilatory support and when they were ready to be weaned. A receiver operating characteristic (ROC) curve was constructed for weaning success, progressive weaning and extubation success. A cut-off point was obtained from these curves from which the sensitivity, specificity, positive and negative predictive values were obtained. Results: The ability of [P(a-ET)CO₂] as a predictor of progressive reduction in ventilator support (n = 118), predictor of weaning from mechanical ventilation (n = 40) and for extubation success (n = 39) was evaluated. The area under the curve (AUC) for progressive weaning, spontaneous breathing trial and extubation success were 0.852, 0.905 and 0.702 and a threshold of 10.5 mm Hg, 9.4 mm Hg and 9.5 mm Hg respectively were obtained. Conclusion: P(a-ET)CO₂ of ≤ 10 mm Hg may be used as an index of weaning during progressive weaning from mechanical ventilation, spontaneous breathing trial and to predict success of extubation.

A 28-year old man required invasive mechanical ventilation in view of organophosphorus poisoning in a peripheral hospital. His trachea was extubated ten days later following which he presented with dysphagia, voice change, burping, fever and cough. He was referred to our hospital for further management. His barium swallow radiograph showed a large tracheo-oesophageal fistula. Therefore, he was scheduled for oesophageal transection and colonic transposition. Following induction of anaesthesia, despite easy laryngoscopy view (Cormack Lehane grade 1), the tracheal intubation was found to be difficult as the tube tended to pass through the fistula into the oesophagus repeatedly as confirmed by absence of capnogram trace. Attempts to bypass the fistula using a fibreoptic scope and even a double lumen tube also failed. Identification of oesophageal intubation would have been missed or possibly detected late in this case with disastrous consequences but for absence of capnogram. Finally, the tracheal tube was successfully negotiated beyond the fistula with the help of a gum elastic bougie directed anteriorly into the trachea and a good capnogram was obtained. The surgery was uneventful and the trachea was extubated 24 h later in the intensive care unit following which the patient developed stridor requiring permanent tracheostomy. This case report illustrates the novel use for gum elastic bougie during tracheal intubation. This also highlights the importance of repeated measurement of tracheal cuff pressure in patients especially those receiving long duration mechanical ventilation.

Tracheomediastinal fistulae may arise due to trauma, severe infection or malignancy. This case report describes management of a patient with tracheomediastinal fistula presenting for a CT-guided radiofrequency ablation of a liver tumour under general anaesthesia. Airway management of these patients can be challenging. Securing the airway prevention of further expansion of pneumomediastinum with intermittent postive pressure ventilation is a major concern.

Inability to secure an airway in a hypoxic patient is a nightmare for every anaesthesiologist. The challenge doubles when such situations occur outside the operating room. Many new airway devices have been designed to overcome this difficulty. Airtraq is a videolaryngoscope which has been successfully used in the operating room as a rescue device during difficult laryngoscopy. We describe two such scenarios where Airtraq was used successfully to secure the airway in patients with poor or no glottic view on direct laryngoscopy.