1 Cuffed or uncuffed tracheal tubes during anaesthesia in infants and small children: time to put the eternal discussion to rest? Editorial: Lönnqvist PA. Br J Anaesth. 2009 Dec;103(6):783-5.
Prospective randomized controlled multi-centre trial of cuffed or uncuffed endotracheal tubes in small children. Weiss M et al. Br J Anaesth. 2009 Dec;103(6):867-73
This multi-centre RCT (n=2246) compared the incidence of post-extubation morbidity and tracheal tube (TT) exchange rates when using cuffed vs uncuffed TT in children aged from birth to 5 yrs. The study demonstrated equipoise between the cuffed and uncuffed groups. Post-extubation stridor was noted in 4.4% of patients with cuffed and in 4.7% with uncuffed TT –a statistically non-significant difference. Notably, the incidence of stridor was higher than initially predicted by study investigators-a fact they attribute to the clear and stringent definitions for stridor and its assessment. The difference in TT exchange rates was highly statistically significant at 2.1% in the cuffed and 30.8% in the uncuffed groups. Maximal cuff pressure was monitored and limited at 20 cm H20 with a pressure release valve and the minimal cuff pressure required to seal the trachea was 10.6 cm H20. A detailed protocol specified size selection for the cuffed TTs whereas the uncuffed TTs were selected according to local guidelines. Limitations include the fact that the trial was terminated early due to a temporary recall of the cuffed TT due to a manufacturing fault. The results obviously only apply to the specific brand of cuffed paediatric TT studied (MicrocuffÒ) and it is likely that cuffed TTs with oversized outer tube diameters, wrongly designed cuffs, and cuffs used without cuff pressure control could cause airway damage. It is worth noting that the first and fifth author of this paper are involved in the development and evaluation of new cuffed paediatric TT. The accompanying editorial suggests this study will become a hallmark paper of paediatric anaesthesia and will definitely change clinical practice.
Take home message: There is evidence to suggest that use of the appropriately designed TTs (MicrocuffÒ TT) in small children provides a reliably sealed airway at cuff pressures of ≤20 cm H20, reduces the need for TT exchanges, and does not increase the risk for post-extubation stridor compared with uncuffed TTs.
See also: Jan 09 Journal Watch (4)
2 Difficult mask ventilation: what needs improvement? Editorial: Salem MR et al. Anesth Analg. 2009 Dec;109(6):1720-2.
Difficult mask ventilation. El-Orbany M et al. Anesth Analg. 2009 Dec;109(6):1870-80.
This review raises concerns about definitions and highlights the pathophysiology, incidence, and prediction of difficult mask ventilation (DMV). DMV has an incidence of between 1.4%-5% depending on criteria used for definition and develops because of multiple factors that are technique related and/or airway related. Errors in technique, equipment malfunction, suboptimal head position, side effects of certain drugs, and above all, pathological partial or complete airway obstruction may all, separately or combined, lead to DMV. Important but often overlooked contributors include inadequate depth of anaesthesia and inadequate muscle relaxation, as well as improperly applied cricoid pressure. Predictors of difficult mask ventilation include increased BMI, history of snoring/OSA, presence of beard, lack of teeth, age>55yr, mallampati III/IV, limited mandibular protrusion, male gender and airway masses/tumour. Unfortunately, this review does not incorporate the data from the large, recent observational study by Kheterpal (Anesthesiology, April, 2009) that found the five independent predictors for DMV were: neck radiation changes, male gender, OSA, mallampati III/IV and presence of a beard. Of concern, there is considerable overlap between features that predispose to DMV and those associated with difficult intubation. If DMV is predicted, preparation for all possible scenarios when anaesthesia induction is planned both enhances success and minimizes risks of the anticipated difficult airway. Shaving the beard or applying an adhesive film over it, weight loss and keeping the dentures in place are just a few examples of correctable factors. Preparatory steps should also include checking availability and working condition of all contents of the difficult airway cart, formulating alternative plans, preparing rescue ventilation devices, and ensuring the availability of an experienced assistant in case help is needed. The authors provide an algorithm for the patient with unexpected DMV. Suggested corrective measures include chin lift, jaw thrust, CPAP, head position, OPA/NPA, NMB followed by call for help, change of operator or 2-person mask ventilation. In addition to the most serious complication of DMV-death or hypoxic brain injury - other potential complications include eye/lip injuries, vomiting/aspiration and bleeding associated with NPA. The accompanying editorial argues that the practice of establishing mask ventilation prior to administration of a NMB is unsound and may contribute to DMV and emphasizes that is imperative that anesthesiologists master the science and art of mask ventilation.
Take home message: Eliciting the predictors of DMV, formulating alternative plans, preparing the proper equipment, and above all, increased awareness of the problem, will ultimately increase patient safety and improve outcome after DMV.
See also: April 09 Journal Watch (3)
3 Comparison of different methods of ventilation via cannula cricothyroidotomy in a trachea-lung model. Flint NJ et al. Br J Anaesth. 2009 Dec;103(6):891-5.
This observational study uses a trachea-lung model to compare methods of providing oxygenation/ventilation via a simulated cannula cricothyroidotomy. The equipment used for comparisons were 4 cannula diameters (20, 16, 14 and 13G) and 3 high pressure devices: an ENK oxygen flow modulator, oxygen from a wall-mounted flow meter attached via a three-way tap to the cannula and a Manujet as well as 2 low pressure devices: a self-inflating resuscitation bag and the oxygen flush of an anaesthetic machine. All experiments were performed with and without a proximal 2.5 mm diameter constriction to simulate upper airway obstruction. In the absence of a proximal constriction, minute ventilations (MVs) delivered via a 20G cannula were <1 litre/min with all devices; only the Manujet delivered MVs>2 litre/min, at cannula sizes of ≥16 G. MVs were greater in the presence of a proximal constriction, but barely exceeded 3 l/min using the low-pressure devices at any cannula size and required a cannula size of >14F to reliably provide a MV above 3L/min with the high pressure devices. The authors suggest practioners should be aware of the potential for pulmonary barotrauma when using high-pressure devices such as the Manujet, and caution about the importance of allowing time for expiration, to prevent breath stacking. In summary, the low-pressure devices (oxygen flush & self-inflating bag) failed to produce any effective ventilation. The authors prefer the purpose-made devices (Manujet & ENK) and their results suggest the only ad-hoc device that performed adequately was the simple 3-way tap and oxygen tubing. In all cases, a cannula of ≥14G is recommended.
Take home message: Purpose-made devices to enable oxygenation/ventilation via a cannula cricothyroidotomy should be available in all areas where anaesthesia is administered or airway interventions are performed.
For related reading this month: Salah N, El Saigh I, Hayes N, McCaul C. Airway injury during emergency transcutaneous airway access: a comparison at cricothyroid and tracheal sites. Anesth Analg. 2009 Dec;109(6):1901-7.
See also: June 09 Journal Watch (1 & 2)
4 Preliminary results of the Australasian Regional Anaesthesia Collaboration: a prospective audit of more than 7000 peripheral nerve and plexus blocks for neurologic and other complications. Barrington MJ et al. Reg Anesth Pain Med. 2009 Nov-Dec;34(6):534-41.
This paper reports on the results of the Victorian initiated Australasian Regional Anaesthesia Collaboration (ARAC). From January 2006 to May 2008, this prospective audit recorded a total of 6950 patients receiving 8189 peripheral nerve or plexus blocks. Of these, 6069 were successfully followed up with a phone call. Thirty patients (0.5%) had clinical features requiring referral for neurologic assessment. Three of these patients were deemed to have a block-related nerve injury (0.08-1.1:1000). The incidence of systemic LA toxicity was 0.98 per 1000 blocks (95% CI 0.42-1.9: 1000). Interestingly, LA toxicity occurred despite the utilization of US guidance in 50% of the blocks with this complication. The estimates of neurological injury and LA toxicity are consistent with previously published figures. Ultrasound was used in 63% of the procedures audited. Notably, the vast majority of the nerve blocks were performed in 2 of the 9 participating centres. Interestingly, TAP blocks were also included in the study. Limitations of the audit include variable timing of follow-up that may have missed temporary symptoms, incomplete follow-up and reliance on individual practioners to record every block performed. It is debatable that the author’s claim that ‘all patients who received nerve blocks performed by all anaesthetist during each hospital’s contributing period were included’ is an accurate statement. This is an ongoing project and more data providers and data collection will lead to future results being more generalizable. The importance and relevance of this work should certainly encourage us to contribute to the audit: www.regional.anaesthesia.org.au
Take home message: This large audit indicates that the incidence of serious complications after peripheral nerve blockade is uncommon and that the origin of neurologic symptoms/signs in the postoperative period is most likely to be unrelated to nerve blockade.
5 Perioperative management of the adult with cystic fibrosis. Huffmyer JL et al. Anesth Analg. 2009 Dec;109(6):1949-61.
This review details the multi-system consequences of cystic fibrosis. CF is the most common lethal genetic disease in Caucasian populations with an incidence of approximately 1in 2500-3200 live Caucasian births. The mutation has been isolated to the CF transmembrane regulator (CFTR) on the long arm of chromosome 7 and leads to pathologic changes in organs that express the CFTR in their epithelial cells. Pulmonary disease is responsible for more than 90% of the morbidity and mortality associated with CF related to chronic pulmonary infection and inflammation, with episodes of acute exacerbation and progressive damage to the lungs. Patients also experience exocrine and endocrine pancreatic disease, including diabetes mellitus, bone disease, hepatobiliary disease and genitourinary disease. Cirrhosis is the second most common cause of death after respiratory failure. Preoperative assessment of a patient with CF must include: recent time course of pulmonary manifestations, current exercise tolerance, recent hospitalizations, infections and requirement for IV antibiotics. Patients with advanced disease may require home oxygen and suffer cor pulmonale with right heart failure. Pancreatic endocrine and/or exocrine dysfunction must be delineated as should evaluation of liver disease. The anaesthetic plan should aim for early tracheal extubation and may require frequent tracheal suctioning and possibly segmental lavage to maintain adequate oxygenation. Neuraxial or regional techniques may be advantageous for surgical anaesthesia +/-post-op analgesia. Special considerations are required for CF patients facing lung transplantation, liver transplantation and pregnancy.
Take home message: CF is a chronic multisystem disease involving primarily the pulmonary and GI systems and may present a spectrum from mild to severe.
6 Innovations in anesthesia education: the development and implementation of a resident rotation for advanced airway management. Crosby E et al. Can J Anaesth. 2009 Dec;56(12):939-959
Need for emergency surgical airway reduced by a comprehensive difficult airway program. Berkow LC et al. Anesth Analg. 2009 Dec;109(6):1860-9.
The ultimate difficult airway: minimizing emergency surgical access. Editorial: Fisher QA. Anesth Analg. 2009 Dec;109(6):1723-5.
This month, two separate journals explore the implementation of a formal difficult airway program for trainees. The article by Crosby describes some of the challenges faced by residents when aiming to become familiar and skilled with the increasing array of airway technology that is now available. The author feels that the only way of effectively meeting these challenges is for training programs to develop structured airway rotations for their trainees. The University of Ottawa has developed a ‘minimal competency kit’ where trainees are instructed to ensure a minimal skills set is attained. The author feels that as a minimum, this should include instruction with the following devices: direct laryngoscope and use of adjuncts, an extraglottic device, a rigid fibreoptic or videolaryngoscope, and a flexible fibreoptic or video intubating system. Training in the performance of invasive airway manoeuvers must also be provided. The author emphasizes that the early use of alternative devices improves the likelihood of success in airway management and reduces the potential for patient injury. He also states that in most instances, experience with the alternative technique is likely of greater importance that the actual technique chosen. Needless to say, the equipment must be available and mentors must be competent with the technology and use it on a regular basis. In the second article Berkow et al. performed a retrospective review of a departmental database to determine whether a comprehensive program to manage difficult airways was associated with a reduced need to secure the airway surgically via cricothyrotomy. The program consisted of 5 parts: 1) an improved patient information system 2) targeted patient evaluation 3) standardized airway equipment 4) training in the form of a difficult airway rotation 5) expert supervision and increased resources. The investigators found this multifaceted program contributed to a sharp reduction in, but not complete elimination of, emergency surgical airways in a large teaching hospital. The accompanying editorial suggests that the newer videolaryngoscopes and rigid optical laryngoscopes will likely render a large fraction of anticipated difficult airways easily managed and states that he believes “we are entering an era in which no anaesthesia or emergency department will want to be without a videolaryngoscope or rigid optical laryngoscope.”
Take home message: Anaesthesia training programs must provide trainees with a variety of airway skills and experience with alternative airway devices to enable safe independent practice in airway management.
7 Pride and prejudice. Editorial: Bogod D. Anaesthesia. 2009 Dec;64(12):1277-1279.
This editorial by the outgoing editor-in-chief of Anaesthesia queries the ‘lamentably low’ position of anaesthetists in the specialist hierarchy in the UK. After his 6-year tenure, the author is left in no doubt that anaesthetists are ‘perhaps uniquely, poorly regarded by hospital management, central government, and, most galling of all, our medical peers.’ The discussion includes the quest for adequate clinical support time and remuneration issues with the author making it plain that he feels it is more than inadequate that ‘we happily take the crumbs from the surgical table, rather than insist on parity of pay.’ Central to these issues is the public perception of anaesthetists that is illustrated by the fact that most patients ‘remain largely in the dark about the role and status of anaesthetists’ and are surprised when they learn that we are ‘real doctors.’ He concludes by making a plea to all anaesthetists to overcome the malaise and fight for the sort of status and recognition that other medical specialties take for granted.
Take home message: Adequate recognition of the technical skill and expertise encompassed by the specialty of anaesthesia remains an elusive goal in many countries around the world.
8 Anesthetic drugs and sustained neuroprotection in acute cerebral ischemia: can we alter clinical outcomes? Editorial: Werner C. Can J Anaesth. 2009 Dec;56(12):883-88
This editorial reviews the evidence for neuroprotection by anaesthetic drugs. The author emphasises that perioperative cerebral ischaemia remains a significant source of morbidity and mortality in cardiac and non-cardiac patients alike. The proposed mechanisms of anaesthetic neuroprotection include reduction of cerebral metabolism and ICP, suppression of seizure activity, lessening of sympathetic discharge and inhibition of synaptic release of excitatory neurotransmitters. Unfortunately, the studies that have been conducted, including recent studies such as GALA (Lancet, 2008), have not provided any evidence that a single pharmacological approach is likely to improve the neurological outcome associated with multiple simultaneous pathological events in patients with parallel variability of co-existing disease. Thus, no strong clinical evidence remains to support the hypothesis that sustained neuroprotection associated with specific anaesthetic agents currently exists. Limitations of the studies that have been performed include selection of inadequate endpoints and failure to properly control important physiological variables such as brain temperature, plasma glucose concentration, PaCO2, pH, and blood pressure.
Take home message: The strongest evidence for neuroprotective interventions suggests the focus should be on the control of key physiological variables to ensure normotension, normoxia, normocapnia, normothermia and normoglycaemia rather than pharmacological therapies.
For related reading this month: Perouansky M et al. Neurotoxicity of general anesthetics: cause for concern? Anesthesiology. 2009 Dec;111(6):1365-71
Other articles in December of potential interest:
AIRWAY Bernardini A et al. Risk of pulmonary aspiration with laryngeal mask airway and tracheal tube: analysis on 65 712 procedures with positive pressure ventilation. Anaesthesia. 2009 Dec;64(12):1289-1294
Bustamante S et al. Two-operator approach to improve eye-hand coordination using the GlideScope((R)) videolaryngoscope. Can J Anaesth. 2009 Dec;56(12):984-985
Adnet F et al. Difficult tracheal intubation in randomized controlled studies: ethical considerations. Can J Anaesth. 2009 Dec;56(12):992-993
Xue FS et al. Airway topicalization during tracheal intubation using the Airtraq((R)) laryngoscope in anesthetized patients. Can J Anaesth. 2009 Dec;56(12):994-995 - Dimitriou VK et al. Comparison of standard polyvinyl chloride tracheal tubes and straight reinforced tracheal tubes for tracheal intubation through different sizes of the Airtraq laryngoscope in anesthetized and paralyzed patients: a randomized prospective study. Anesthesiology. 2009 Dec;111(6):1265-70. -
Stanley GD. Is it time for a Glidescope letter? Anesthesiology. 2009 Dec;111(6):1391.
Turkstra TP et al. The Flex-It stylet is less effective than a malleable stylet for orotracheal intubation using the GlideScope. Anesth Analg. 2009 Dec;109(6):1856-9.
Arslan ZI et al. Tracheal intubation in patients with rigid collar immobilisation of the cervical spine: a comparison of Airtraq and LMA CTrach devices* Anaesthesia. 2009 Dec;64(12):1332-1336.
CARDIAC Editorial: Nussmeier NA et al. The next generation of colloids: ready for "prime time"? Anesth Analg. 2009 Dec;109(6):1715-7.
De Hert SG et al. Drugs mediating myocardial protection. Eur J Anaesthesiol. 2009 Dec;26(12):985-95.
Grigore AM et al. A core review of temperature regimens and neuroprotection during cardiopulmonary bypass: does rewarming rate matter? Anesth Analg. 2009 Dec;109(6):1741-51. Review.
Grocott HP. PRO: Temperature regimens and neuroprotection during cardiopulmonary bypass: does rewarming rate matter? Anesth Analg. 2009 Dec;109(6):1738-40. -
Cook DJ. CON: Temperature regimens and neuroprotection during cardiopulmonary bypass: does rewarming rate matter? Anesth Analg. 2009 Dec;109(6):1733-7.
Klein AA et al. Transcatheter aortic valve insertion: anaesthetic implications of emerging new technology. Br J Anaesth. 2009 Dec;103(6):792-9.
CRITICAL CARE Payen JF et al. Pain assessment is associated with decreased duration of mechanical ventilation in the intensive care unit: a post Hoc analysis of the DOLOREA study. Anesthesiology. 2009 Dec;111(6):1308-16.
Editorial: Kumar AB et al. Pain assessment, sedation, and analgesic administration in the intensive care unit. Anesthesiology. 2009 Dec;111(6):1187-8.
GENERAL TOPICS
Chikungwa M. Current nitrous oxide use in general anaesthesia: an electronic survey. Eur J Anaesthesiol. 2009 Dec;26(12):1088-90.
Hofer CK et al. Minimally invasive haemodynamic monitoring. Eur J Anaesthesiol. 2009 Dec;26(12):996-1002.
Brzezinski M et al. Radial artery cannulation: a comprehensive review of recent anatomic and physiologic investigations. Anesth Analg. 2009 Dec;109(6):1763-81.
McGain F et al. An audit of intensive care unit recyclable waste. Anaesthesia. 2009 Dec;64(12):1299-1302. -
Mehta V. Peripheral opioid antagonism. Anaesthesia. 2009 Dec;64(12):1279-1282.
Nho JS et al. Effects of maintaining a remifentanil infusion on the recovery profiles during emergence from anaesthesia and tracheal extubation. Br J Anaesth. 2009 Dec;103(6):817-21.
NEUROANAESTHESIA
Editorial: Stocchetti N. Intracranial pressure, brain vessels, and consciousness recovery in traumatic brain injury. Anesth Analg. 2009 Dec;109(6):1726-7.
OBSTETRICS Ko JY et al. Clinical implications of neuraxial anesthesia in the parturient with scoliosis. Anesth Analg. 2009 Dec;109(6):1930-4
D'Onofrio P et al. The efficacy and safety of continuous intravenous administration of remifentanil for birth pain relief: an open study of 205 parturients. Anesth Analg. 2009 Dec;109(6):1922-4.
Hinova A et al. Systemic remifentanil for labor analgesia. Anesth Analg. 2009 Dec;109(6):1925-9.
Phillips LE et al. Recombinant activated factor VII in obstetric hemorrhage: experiences from the Australian and New Zealand Haemostasis Registry. Anesth Analg. 2009 Dec;109(6):1908-15.
Lee DH et al. Magnesium sulphate has beneficial effects as an adjuvant during general anaesthesia for Caesarean section. Br J Anaesth. 2009 Dec;103(6):861-6.
PAEDIATRICS Chorney JM et al. Healthcare provider and parent behavior and children's coping and distress at anesthesia induction. Anesthesiology. 2009 Dec;111(6):1290-6.
PAIN Richebé P et al. Perioperative pain management in the patient treated with opioids: Continuing Professional Development. . Can J Anaesth. 2009 Dec;56(12):969-981
Roullet S et al. Preoperative opioid consumption increases morphine requirement after leg amputation. . Can J Anaesth. 2009 Dec;56(12):908-913
Editorial: Morley-Forster PK. The vexing problem of post-amputation pain: What is the optimal perioperative pain management for below-knee amputation? Can J Anaesth. 2009 Dec;56(12):895-900
PERIOPERATIVE MEDICINE Editorial: Hall GM. Management of diabetes during surgery: 30 yr of the Alberti regimen. Br J Anaesth. 2009 Dec;103(6):789-91
REGIONAL ANAESTHESIA Editorial: Bodenham AR et al. General anaesthesia vs local anaesthesia: an ongoing story. Br J Anaesth. 2009 Dec;103(6):785-9.
Editorial: Sites BD et al. Ultrasound in regional anesthesia: where should the "focus" be set? Reg Anesth Pain Med. 2009 Nov-Dec;34(6):531-3
Manickam B et al. Feasibility and efficacy of ultrasound-guided block of the saphenous nerve in the adductor canal. Reg Anesth Pain Med. 2009 Nov-Dec;34(6):578-80.
Borges BC et al. Sonoanatomy of the lumbar spine of pregnant women at term. Reg Anesth Pain Med. 2009 Nov-Dec;34(6):581-5.
RESEARCH Editorial: Kheterpal S et al. Too much of a good thing is wonderful: observational data for perioperative research. Anesthesiology. 2009 Dec;111(6):1183-4
Editorial: Kheterpal S. Perioperative comparative effectiveness research: an opportunity calling. Anesthesiology. 2009 Dec;111(6):1180-2
RISK MANAGEMENT
Cranshaw J et al. Litigation related to drug errors in anaesthesia: an analysis of claims against the NHS in England 1995-2007. Anaesthesia. 2009 Dec;64(12):1317-1323.
Written by Maryanne Balkin, December 2009
Feedback welcome: M.Balkin@alfred.org.au
Disclaimers:
1 Best attempts are made to include articles representative of recent publications but no attempt is made to include every important article.
2 Commentary & take home message is only one of many possible opinions/interpretations of the literature.
For other 2009 editions of journal watch: http://www.anaesthesiacases.com.au/cpd