Professor Tess Cramond (1926–2015): Contributions to Anaesthesia and Pain Medicine

Professor Tess Cramond joined the Queensland anaesthesia workforce in 1958, and contributed to high standards of clinical practice, pain management, training, scholarship and research. Evidence of her excellence, within the clinical, political and community spheres was recognised by multiple awards. Though deceased in 2015, she remains a role model for all physicians, using her expert knowledge, technical skills, clinical reasoning, emotions and values for the benefit of the individuals and community which she served.

Does objective measurement of tracheal tube cuff pressures minimise adverse effects and maintain accurate cuff pressures? A systematic review and meta-analysis

Correct inflation pressures of the tracheal cuff are recommended to ensure adequate ventilation and prevent aspiration and adverse events. However there are conflicting views on which measurement to employ. The aim of this review was to examine whether adjustment of cuff pressure guided by objective measurement, compared with subjective measurement or observation of the pressure value alone, was able to prevent patient-related adverse effects and maintain accurate cuff pressures. A search of PubMed, Web of Science, Embase, CINAHL and ScienceDirect was conducted using keywords 'cuff pressure' and 'measure*' and related synonyms. Included studies were randomised or pseudo-randomised controlled trials investigating mechanically ventilated patients both in the intensive care unit and during surgery. Outcomes included adverse effects and the comparison of pressure measurements. Pooled analyses were performed to calculate risk ratios, effect sizes and 95% confidence intervals. Meta-analysis found preliminary evidence that adjustment of cuff pressure guided by objective measurement as compared with subjective measurement or observation of the pressure value alone, has benefit in preventing adverse effects. These included cough at two hours (odds ratio [OR] 0.42, confidence interval [CI] 0.23 to 0.79, P=0.007), hoarseness at 24 hours (OR 0.49, CI 0.31 to 0.76, P <0.002), sore throat (OR 0.73, CI 0.54 to 0.97, P <0.03), lesions of the trachea and incidences of silent aspiration (P=0.001), as well as maintaining accurate cuff pressures (Hedges' g 1.61, CI 2.69 to 0.53, P=0.003). Subjective measurement to guide adjustment or observation of the pressure value alone may lead to patient-related adverse effects and inaccuracies. It is recommended that an objective form of measurement be used.

Anaesthetists' experiences with the early labour epidural recommendation for obese parturients: a qualitative study

Caring for obese pregnant women presents challenges for all medical professionals. Despite a lack of supporting evidence, expert opinion and international guidelines suggest early labour epidural insertion for obese women. Anecdotally this is not supported by all anaesthetists. This qualitative study explored the experiences of anaesthetists regarding early epidural analgesia in obese parturients, to answer the research question: Are anaesthetists consistent in how they apply early epidural analgesia in obese parturients? Personal in-depth interviews with 42 specialist anaesthetists working in south-east Queensland, Australia, were completed between February and April, 2015. Leximancer™ text analysis software applied a validated algorithm to the data to identify themes and concepts. The major themes were explored by the first author to answer the research question. Three major themes were identified: the demands associated with caring for obese women; concern regarding the anaesthetic technique used in obese women; and the importance of communication with obstetric staff. Disagreement regarding interpretation and application of early epidural analgesia was identified within this group of anaesthetists. These anaesthetists were inconsistent in how they interpreted and applied early epidural analgesia for obese parturients, with some questioning the validity of the practice. The combination of uncertainty, urgency and technical difficulty presented by obese parturients provoked anxiety in these clinicians, particularly the anticipation of unplanned general anaesthesia. Consistent anaesthetic practice could improve the implementation of early epidural analgesia in obese parturients.

Anaesthetic Management of Obese Parturients: What is the Evidence Supporting Practice Guidelines?

Increasing rates of obesity in western populations present management difficulties for clinicians caring for obese pregnant women. Various governing bodies have published clinical guidelines for the care of obese parturients. These guidelines refer to two components of anaesthetic care: anaesthetic consultation in the antenatal period for women with a body mass index (BMI) > 40 kg/m2 and the provision of early epidural analgesia in labour. These recommendations are based on the increased incidence of obstetric complications and the predicted risks and difficulties in providing anaesthetic care. The concept behind early epidural analgesia is logical—site the epidural early, use it for surgical anaesthesia and avoid general anaesthesia if surgery is required. Experts support this recommendation, but there is weak supporting evidence. It is known that the management of labour epidurals in obese women is complicated and that women with extreme obesity require higher rates of general anaesthesia. Anecdotally, anaesthetists view and apply the early epidural recommendation inconsistently and the acceptability of early epidural analgesia to pregnant women is variable. In this topic review, we critically appraise these two practice recommendations. The elements required for effective implementation in multidisciplinary maternity care are considered. We identify gaps in the current literature and suggest areas for future research. While prospective cohort studies addressing epidural extension (‘top-up’) in obese parturients would help inform practice, audit of local practice may better answer the question “is early epidural analgesia beneficial to obese women in my practice?”.

Reducing the immediate availability of red blood cells in cardiac surgery, a single-centre experience

Background

In our institution, we have redefined our criteria for direct availability of red blood cell (RBC) units in the operation room. In this study, we sought to evaluate the safety of applying this new logistical policy of blood transfusion in the first preliminary group of patients.

Methods

In March 2010, we started a new policy concerning the elective availability of RBC units in the operation room. This policy was called: No Elective Red Cells (NERC) program. The program was applied for patients undergoing primary isolated coronary artery bypass grafting (CABG) or single valve surgery. No elective RBC units were preoperatively ordered for these patients. In case of urgent need, blood was delivered to the operating room within 20 min. The present study includes the first 500 patients who were managed according to this policy. Logistic regression analyses were performed to investigate the impact of biomedical variables on fulfilling this NERC program.

Results

The majority of patients (n = 409, 81 %) did not receive any RBCs during the hospital stay. In patients who did receive RBCs (n = 91, 19 %), 11 patients (2.2 %) received RBCs after 24 h postoperatively. Female gender, left ventricular ejection fraction (LVEF) and EuroSCORE were significant predictors for the need of blood transfusion (OR = 3.12; 2.79; 1.17 respectively).

Conclusion

In a selected group of patients, it is safe to perform cardiac surgery without the immediate availability of RBCs in the operating room. Transfusion was avoided in 81 % of these patients. Female gender, LVEF and EuroSCORE were associated with blood transfusion.

Perioperative statin therapy in patients at high risk for cardiovascular morbidity undergoing surgery: a review

Statins feature documented benefits for primary and secondary prevention of cardiovascular disease and are thought to improve perioperative outcomes in patients undergoing surgery. To assess the clinical outcomes of perioperative statin treatment in statin-naive patients undergoing surgery, a systematic review was performed. Studies were included if they met the following criteria: randomized controlled trials, patients aged ≥18 yr undergoing surgery, patients not already on long-term statin treatment, reported outcomes including at least one of the following: mortality, myocardial infarction, atrial fibrillation, stroke, and length of hospital stay. The following randomized clinical trials were excluded: retrospective studies, trials without surgical procedure, trials without an outcome of interest, studies with patients on statin therapy before operation, or papers not written in English. The literature search revealed 16 randomized controlled studies involving 2275 patients. Pooled results showed a significant reduction in (i) mortality [risk ratio (RR) 0.53, 95% confidence interval (CI) 0.30-0.94, P=0.03], (ii) myocardial infarction (RR 0.54, 95% CI 0.38-0.76, P<0.001), (iii) perioperative atrial fibrillation (RR 0.53, 95% CI 0.43-0.66, P<0.001), and (iv) length of hospital stay (days, mean difference -0.58, 95% CI -0.79 to -0.37, P<0.001) in patients treated with a statin. Subgroup analysis in patients undergoing non-cardiac surgery showed a decrease in the perioperative incidence of mortality and myocardial infarction. Consequently, anaesthetists should consider prescribing a standard-dose statin before operation to statin-naive patients undergoing cardiac surgery. However, there are insufficient data to support final recommendations on perioperative statin therapy for patients undergoing non-cardiac surgery.

Endotracheal intubation using videolaryngoscopy causes less cardiovascular response compared to classic direct laryngoscopy, in cardiac patients according a standard hospital protocol

INTRODUCTION

Previous studies comparing Glidescope and classic direct laryngoscopy did not show an attenuation of CV responses to endotracheal intubation. In the present study, we hypothesize that indirect videolaryngoscopy can attenuate cardiovascular responses to endotracheal intubation.

METHODS

In a randomized cross-over study, eighty adults (ASA PS II-III) were included. Both direct and indirect videolaryngoscopies were used in a random order, in the same patient. Cardiovascular responses to intubation were recorded as a relative change in rate pressure product (RPP = systolic blood pressure times heart rate) from baseline values. A linear mixed model was used to study the association between the outcome variable RPP and the type of laryngoscope used.

RESULTS

The relative increase of the RPP at intubation was significantly smaller (i.e. 27%, P < 0.001) using videolaryngoscopy compared to the classic direct laryngoscopy. Cardiovascular responses were blunted by an additional 10.2% (P = 0.029), when the patient was on beta blockade.

CONCLUSIONS

Our study shows less hemodynamic responses during endotracheal intubation using indirect videolaryngoscopy compared to classic direct laryngoscopy.

Personality dimensions and their relationship with job satisfaction amongst Dutch nurse anaesthetists

AIM

This study investigates the relationship between personality dimensions and job satisfaction.

BACKGROUND

The shortage of nurses, and those voluntarily leaving their jobs, continues to be a problem affecting the delivery of healthcare all over the world, including anaesthesia. If it is found that nurse anaesthetists with certain personality types have high levels of job satisfaction, the information may be helpful for the retention of nurse anaesthetists.

METHODS

A questionnaire was distributed amongst Dutch nurse anaesthetists. Factor and multiple regression analyses were performed to reveal personality dimensions and their impact on job satisfaction.

RESULTS

Nine hundred and twenty-three questionnaires were completed and analysed (46% response rate). Two personality dimensions -'easy going' and 'orderly'- explained 3.5% of the variance in job satisfaction.

CONCLUSION

Personality dimensions as measured with the Myers-Briggs Type Indicator (MBTI) are only minimally relevant in predicting job satisfaction amongst Dutch nurse anaesthetists.

IMPLICATIONS FOR NURSING MANAGEMENT

Before using personality traits as a selection tool for retaining employees, it is important to understand the relationship of particular personalities to job satisfaction; it is also important to know which combination of personality traits is likely to create a highly cohesive work group.

Prehospital airway management: A prospective case study

We conducted a one-year prospective study involving a prehospital Emergency Medical Service in the Netherlands to investigate the incidence of failed or difficult prehospital endotracheal intubation. During the study period the paramedics were asked to fill in a registration questionnaire after every endotracheal intubation. Of the 26,271 patient contacts, 256 endotracheal intubations were performed by paramedics in one year. Endotracheal intubation failed in 12 patients (4.8%). In 12.0% of 249 patients, a Cormack and Lehane grade III laryngoscopy was reported and a grade IV laryngoscopy was reported in 10.4%. The average number of endotracheal intubations per paramedic in one year was 4.2 and varied from zero to a maximum of 12. The median time between arrival on the scene and a positive capnograph was 7 min.38 s in the case of a Cormack and Lehane grade I laryngoscopy and 14 min.58 s in the case of a Cormack and Lehane grade 4 laryngoscopy. The incidence of endotracheal intubations performed by Dutch paramedics in one year was low, but endotracheal intubation was successful in 95.2%, which is comparable with findings in international literature. Early capnography should be used consistently in prehospital airway management.

Successful use of videolaryngoscopy in an adult patient with acute epiglottitis: a case report

Acute epiglottitis is a potentially life-threatening infection of the supraglottic structures, which can lead to sudden, fatal airway obstruction. Different techniques have been described to facilitate tracheal intubation in acute epiglottitis. We describe the successful intubation, with the help of the videolaryngoscope, of a 60-year-old female with acute epiglottitis. On admission the patient was ill and severely distressed, sitting in the upright position, drooling saliva, showing severe inspiratory stridor, hyperventilation, but no trismus. Intubation was performed in OR conditions with difficult intubation equipment including fiberoptic bronchoscope, videolaryngscope, laryngeal mask airway and surgical tracheostomy ready for use. After pre-oxygenation for three minutes with 100% oxygen with the patient still in the sitting position, induction was performed with 250 mg propofol i.v. The patient was subsequently positioned supine. Face mask ventilation was successful with capnographic tracing and 100 mg succinylcholine was administered. Videolaryngoscopy was performed and a red, swollen epiglottitis with pin point lumen was seen. Intubation with a 5 mm microlarynx tube was successful at the first attempt. This is the first case describing intubation using videolaryngoscopy in an adult patient with acute epiglottitis. Videolaryngoscopy has already proven to be an excellent intubation device in normal and difficult airways. Direct laryngoscopy in patients with epiglottitis may be difficult due to the swelling and distortion of the airway. This case report shows that videolaryngoscopy is a good alternative intubation device option in adults with acute epiglottitis. Nevertheless, all other precautions (difficult airway trolley, surgical tracheostomy) need to be ready for immediate use.

Laparoscopic cholecystectomy under segmental thoracic spinal anaesthesia: a feasibility study

BACKGROUND

Laparoscopic surgery is normally performed under general anaesthesia, but regional techniques have been found beneficial, usually in the management of patients with major medical problems. Encouraged by such experience, we performed a feasibility study of segmental spinal anaesthesia in healthy patients.

METHODS

Twenty ASA I or II patients undergoing elective laparoscopic cholecystectomy received a segmental (T10 injection) spinal anaesthetic using 1 ml of bupivacaine 5 mg ml-1 mixed with 0.5 ml of sufentanil 5 microg ml-1. Other drugs were only given (systemically) to manage patient anxiety, pain, nausea, hypotension, or pruritus during or after surgery. The patients were reviewed 3 days postoperatively by telephone.

RESULTS

The spinal anaesthetic was performed easily in all patients, although one complained of paraesthesiae which responded to slight needle withdrawal. The block was effective for surgery in all 20 patients, six experiencing some discomfort which was readily treated with small doses of fentanyl, but none requiring conversion to general anaesthesia. Two patients required midazolam for anxiety and two ephedrine for hypotension. Recovery was uneventful and without sequelae, only three patients (all for surgical reasons) not being discharged home on the day of operation.

CONCLUSIONS

This preliminary study has shown that segmental spinal anaesthesia can be used successfully and effectively for laparoscopic surgery in healthy patients. However, the use of an anaesthetic technique involving needle insertion into the vertebral canal above the level of termination of the spinal cord requires great caution and should be restricted in application until much larger numbers of patients have been studied.

Matching the peripheral intravenous catheter to the individual patient

Up to eighty percent of all patients admitted to hospital worldwide will receive a peripheral IV and this procedure is now considered indispensable to human health. However, despite its global use, the choice of catheter is not always governed by clear and universal guidelines. After reviewing the few best-practice recommendations which exist, we propose a patient--and therapy--driven matrix for deciding on the gauge and length of peripheral catheter for the individual patient. This matrix takes patient age, clinical stability, current state of veins, therapy duration and the nature of the medication to be delivered into consideration. Use of such a matrix will not deliver a formulaic answer but will orient choices along logical, evidence-based lines. This approach will be an advance on the all-too-common reliance on habit and tradition in the choice of peripheral IV catheter.

The anatomy of the thoracic spinal canal investigated with magnetic resonance imaging (MRI)

BACKGROUND AND OBJECTIVES

Anesthesiologists are reluctant to consider higher levels for spinal anesthesia, largely due to direct threats to the spinal cord. The goal of this study is to investigate, with magnetic resonance imaging (MRI), the distances between the relevant structures of the spinal canal (spinal cord, thecal tissue, etc.) to determine modal anatomical positions for neuraxial anesthesia.

METHOD

A group of 19 patients were imaged with an MRI scanner in supine position. Medial sagittal slices of the thoracic and lumbar spine were measured for the relative distances between anatomical structures, including epidural space, dura, and spinal cord.

RESULTS

The posterior dura - spinal cord distance is significantly greater in the middle thoracic region than at upper and lower thoracic levels (e.g. T6 9.5 +/- 1.8 mm, T12 3.7 +/- 1.2 mm, p < 0.001, T1 4.7 +/- 1.7 mm, p < 0.001). There is variation in modal distances between the structures important for neuraxial anesthesia, at different levels of the spinal canal.

CONCLUSIONS

The spinal cord tends to follow the straightest line through the imposed geometry of the spine. Considering the necessary angle of entry of the needle at mid-thoracic levels, there is relatively (more than at upper thoracic and lumbar levels) substantial separation of cord and surrounding thecal tissue. Anesthesiologists perform spinal blockades up to the L2-L3 interspace, but avoid higher levels for fear of neurological damage. The information that there is substantially more space in the dorsal subarachnoid space at thoracic level, might lead to potential applications in regional anesthesia. In contrast, the cauda equina sits more dorsally in the lumbar region.

Segmental spinal anaesthesia for cholecystectomy in a patient with severe lung disease

Occasionally patients awaiting heart or lung transplant because of terminal disease require other types of surgery, but present significant challenges to the anaesthetist because of impaired organ function. Regional anaesthesia may have much to offer such patients and we here report one who underwent successfully a laparoscopic cholecystectomy under segmental subarachnoid (spinal) anaesthesia performed at the low thoracic level. The anatomical and physiological consequences of such a technique are discussed.

Comparison of cuff-pressure changes in LMA-Classic and the new Soft Seal laryngeal masks during nitrous oxide anaesthesia in spontaneous breathing patients

BACKGROUND AND OBJECTIVE

There are concerns over the intra-cuff pressure of the laryngeal mask and laryngopharyngeal morbidity. In a randomized study, the authors compared cuff-pressure changes in the LMA-Classic and the new disposable Soft Seal laryngeal mask during nitrous oxide anaesthesia.

METHODS

Two-hundred adult patients were randomly assigned to a size 4 laryngeal mask in two equal-sized groups for airway management: (a) the re-usable LMA-Classic, or (b) the new disposable Soft Seal laryngeal mask. Anaesthesia was administered with fentanyl, propofol, nitrous oxide, O2 and sevoflurane. The cuff pressures, adjusted to 45 mmHg at insertion, were monitored continuously until the end of the operation without any further attempt to reduce cuff pressure. On removal of the laryngeal mask, any blood at all was considered positive. Patients were requested to report any sore throat at 2 and 24 h postoperatively.

RESULTS

During nitrous oxide anaesthesia, cuff pressures increased in the LMA-Classic group from 45 to 100.3 mmHg and from 45 to 46.8 mmHg in the Soft Seal laryngeal mask group (P < 0.001). The incidence of sore throat was significantly higher at 2 h postoperatively when using the LMA-Classic, although there was no difference at 24 h following the operation. Macroscopic blood was only seen on four occasions in the LMA-Classic group (not significant).

CONCLUSIONS

During nitrous oxide anaesthesia, cuff pressure increases in the LMA-Classic mask were significantly higher than those of the Soft Seal laryngeal mask. Trauma to patients, as assessed by the incidence of sore throat in the early postoperative period was significantly higher in the LMA-Classic group. Cuff pressures should be monitored during nitrous oxide anaesthesia when LMA-Classic is used but to do so is of less importance when using the disposable Soft Seal laryngeal mask.