Umesh Goneppanavar

Anaesthesia machine: checklist, hazards, scavenging.

From a simple pneumatic device of the early 20th century, the anaesthesia machine has evolved to incorporate various mechanical, electrical and electronic components to be more appropriately called anaesthesia workstation. Modern machines have overcome many drawbacks associated with the older machines. However, addition of several mechanical, electronic and electric components has contributed to recurrence of some of the older problems such as leak or obstruction attributable to newer gadgets and development of newer problems. No single checklist can satisfactorily test the integrity and safety of all existing anaesthesia machines due to their complex nature as well as variations in design among manufacturers. Human factors have contributed to greater complications than machine faults. Therefore, better understanding of the basics of anaesthesia machine and checking each component of the machine for proper functioning prior to use is essential to minimise these hazards. Clear documentation of regular and appropriate servicing of the anaesthesia machine, its components and their satisfactory functioning following servicing and repair is also equally important. Trace anaesthetic gases polluting the theatre atmosphere can have several adverse effects on the health of theatre personnel. Therefore, safe disposal of these gases away from the workplace with efficiently functioning scavenging system is necessary. Other ways of minimising atmospheric pollution such as gas delivery equipment with negligible leaks, low flow anaesthesia, minimal leak around the airway equipment (facemask, tracheal tube, laryngeal mask airway, etc.) more than 15 air changes/hour and total intravenous anaesthesia should also be considered.

Idiopathic subglottic stenosis in pregnancy: A deceptive laryngoscopic view

A 28-year-old lady with term gestation, pre-eclampsia and a vague history of occasional breathing difficulty, on irregular bronchodilator therapy, was scheduled for category 1 lower segment caesarean section in view of foetal distress. A Cormack-Lehane grade 1 direct laryngoscopic view was obtained following rapid sequence induction. However, it was not possible to insert a 7.0 or 6.0 size styleted cuffed tracheal tube in two attempts. Ventilation with a supraglottic device was inadequate. Airway was secured with a 4.0 size microlaryngeal surgery tube with difficulty. Computed tomography scan of the neck following tracheostomy for failed extubation revealed subglottic stenosis (SGS) with asymmetric arytenoid calcification. This report describes the management of a rare case of unrecognised idiopathic SGS in pregnancy.

Airway management in an infant with congenital trismus: the role of retrograde intubation

Abstract Congenital trismus is a serious anomaly, and establishment of an airway for surgical correction is a challenge. In the case of limited mouth opening, the nasal route is the only available option to secure the airway via the supraglottic route. Various airway management options include blind intubation, retrograde intubation and fibre-optic intubation, failing which a tracheostomy might be needed. We present the airway management of a seven-month-old infant with congenital trismus who was scheduled for corrective surgery. After several unsuccessful attempts at blind nasal intubation, with the infant on spontaneous ventilation, breathing sevoflurane in oxygen, we managed to secure the airway successfully by retrograde intubation.

Intrathoracic cystic hygroma with sudden respiratory distress mimicking pneumonia

Benign cystic lesions such as cystic hygroma commonly manifest as progressively increasing swelling in the neck with or without compression effects. Rarely, they present with sudden respiratory distress in instances such as infection or haematoma resulting in a sudden increase in the size of the tumour. We present a seven month old child with sudden onset respiratory distress without any obvious neck swelling. The chest X ray findings correlated with the history and were suggestive of right upper lobe pneumonia that leads to a wrong diagnosis of aspiration pneumonia. However, presence of a deviated trachea in the neck raised a suspicion of possible mass. Computed tomogram showed a large cystic mass in the right upper mediastinum with tracheal collapse. We caution intensivists and paediatricians that sudden respiratory distress in infants in the absence of obvious neck swelling does not rule out possibility of intrathoracic tumour.

Jaw lift causes less laryngeal interference during lightwand-guided intubation than combined jaw and tongue traction applied by single operator

Lightwand-guided intubation is a semi-blind technique that takes advantage of the anterior location of the trachea in relation to the oesophagus. Fibreoptic evaluation of lightwand-guided intubation has revealed a possibility of laryngeal interference and epiglottic distortion. Jaw lift, tongue traction or a combination of both have been used to assist in lightwand-guided intubation. This study fibreoptically evaluates lightwand-guided intubation using jaw lift and combined jaw and tongue traction. Eighty four patients with normal airway undergoing general anaesthesia were studied. This randomised, double blinded, cross over study was done in two phases. First phase – after achieving adequate depth of anaesthesia, a fibrescope was advanced nasally, and lightwand-guided intubation was carried out under direct fibreoptic visualisation with the aid of either jaw lift or combined jaw and tongue traction. Second phase – Extubation followed by reintubation using the other manoeuvre. Interference with laryngeal structures during intubation and position of the epiglottis at the end of intubation were noted. Epiglottic distortion (deviated to one side/infolded into trachea) was observed in 6 patients with jaw lift and 17 patients with combined jaw and tongue traction (P=0.003). Laryngeal interference was significantly higher (P=0.012) with combined manoeuvre (30/78) than with jaw lift alone (9/81). Although lightwand-guided intubation can be performed quickly and easily, interference with laryngeal structures and distortion of the epiglottis can occur. Jaw lift manoeuvre causes less laryngeal interference than combined jaw and tongue traction applied by a single operator.

Comparative effects of buprenorphine and dexmedetomidine as adjuvants to bupivacaine spinal anaesthesia in elderly male patients undergoing transurethral resection of prostrate: A randomized prospective study

Background and Aims: Transurethral resection of the prostate is a commonly performed urological procedure in elderly men with spinal anaesthesia being the technique of choice. Use of low-dose spinal anesthetic drug with adjuvants is desirable. This study compares the sensorimotor effects of addition of buprenorphine or dexmedetomidine to low-dose bupivacaine. Methods: Sixty patients were randomly allocated to three different groups. All received 1.8 mL 0.5% hyperbaric bupivacaine intrathecally. Sterile water (0.2 mL) or buprenorphine (60 μg) or dexmedetomidine (5 μg) was added to control group (Group C), buprenorphine group (Group B), and dexmedetomidine group (Group D), respectively. Time to the first analgesic request was the primary objective, and other objectives included the level of sensory-motor block, time to two-segment regression, time to S1sensory regression and time to complete motor recovery. ANOVA and post hoc test were used for statistical analysis. The value of P < 0.05 was considered statistically significant. Results: All sixty patients completed the study. Postoperative analgesia was not required in the first 24 h in a total of 10 (50%), 12 (60%) and 15 (75%) patients in groups C, B, and D, respectively. Time to S1regression was 130 ± 46 min (Group C), 144 ± 51.3 min (Group B) and 164 ± 55.99 min (Group D), P = 0.117.Time to complete motor recovery was 177 ± 56.9 min (Group C), 236 ± 60 min (Group B) and 234 ± 61.71 min (Group D), P < 0.001. Conclusion: Addition of buprenorphine (60 μg) or dexmedetomidine (5 μg) to intrathecal bupivacaine for transurethral resection prolongs the time to the first analgesic request with comparable recovery profile.

Anesthetic management of caesarean section in a patient with double outlet right ventricle

Double outlet right ventricle (DORV) is a rare congenital heart defect involving the great arteries. In DORV, both aorta and pulmonary artery arise from the right ventricle resulting in admixture of blood. We report a 22-year-old parturient with DORV and severe pulmonary stenosis who underwent caesarean delivery at 36 weeks gestation with low dose combined spinal-epidural anesthesia. This lady was assessed by echocardiogram to have situs inversus, dextrocardia, severe pulmonary artery stenosis (gradient = 146 mm Hg), DORV with subarterial VSD (1 cm). She had 95% room air saturation and her blood investigations were within normal limits. We established a peripheral venous access and radial arterial line for continuous blood pressure monitoring. Combined spinal epidural anesthesia was considered a better option. Epidural catheter was secured at L 2 -L 3 space and fixed after giving test dose 3 mL 2% lignocaine. Subarachnoid block administered at L 3 -L 4 level using 1.2 mL of 0.5% heavy bupivacaine. A sensory block of T 10 was obtained which was supplemented with 4 mL 0.75% ropivacaine to obtain a level of T 6 . Patient tolerated the procedure well. She was shifted to post-operative ICU. Post-operative pain was managed with epidural 0.2% ropivacaine at 4 mL/h. Patient remained hemodynamically stable throughout the procedure and in the postoperative period while she was being followed up for subsequent 48 h.

Light at a tunnel's end: The lightwand as a rapid tracheal location aid when encountering false passage during tracheostomy

False passage and loss of airway during tracheostomy are not uncommon, especially in patients with short and thick necks. Distorted neck anatomy following either repeated insertion attempts or due to underlying malignancy may make it very difficult to locate the trachea even while attempting open/surgical tracheostomy, despite good exposure of the neck in such situations. The lightwand is not an ideal device for tracheal intubation in such patients. However, it can be useful in these patients while performing open tracheostomy. Passing the lightwand through the orotracheal tube can aid in rapid identification of the trachea in such situations and may help reduce the occurrence of complications subsequent to repeated false passage. We report a series of four such cases where use of lightwand aided in rapidly locating the trachea during tracheostomy complicated by distorted anatomy.

Laryngeal injuries and tracheal intubating conditions with or without muscle relaxation I

To the Editor, We read with avid interest the recently published study regarding laryngeal injuries and tracheal intubating conditions with or without the use of muscle relaxants. While we are intrigued by the findings, we have several concerns regarding the study design. The study reports that, at time T0 ? 50 s, the study drug 0.15 ml kg -1 (cisatracurium 1 mg ml or saline iv) was administered over 10 s. Next, at T0 ? 100 s, propofol 2.5 mg kg -1 iv was administered over 50 s. Ventilation via facemask was initiated upon loss of eyelash reflex. Assuming the onset of propofol’s action was coincidental with the completion of its administration, there remained an approximate time lag of 90 s from completion of the administration of cisatracurium and completion of the administration of propofol. The report does not indicate which anesthetic agents were administered during bag-mask ventilation prior to attempting laryngoscopy. This aspect concerns us, as patients might have experienced ‘‘inability to breathe or discomfort’’ prior to their loss of consciousness. A second concern is the uncertainty, from the methodological description, as to whether a supplemental muscle relaxant was administered intraoperatively and whether the observer recorded signs of patient movement or ‘‘coughing’’ in response to surgical stimulation. Finally, the reported study had a lower incidence of sore throat compared to other studies. As this study involved only female patients, it is possible that the vigorous response to laryngoscopy and tracheal intubation indicated by its final assessment would not have materialized with male subjects who have different muscularity. We believe that these factors are important considerations when evaluating both the incidence and the severity of postoperative sore throat. In our view, further studies in this area should give additional consideration to the timing of the administration of muscle relaxants in relation to pharmacodynamic considerations, especially the onset times of the muscle relaxant and the induction agent.