bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiovascular Effects of Sedative Infusions of Propofol and Midazolam after Spinal Anaesthesia
Authors: Blake D. W. , Donnan G. , Novella J. , Hackman C.
Published: January 2019

The cardiovascular effects of intravenous sedation were studied in fifty patients after spinal anaesthesia for lower limb or pelvic surgery. Twenty patients received propofol (mean dosage 74 (SD 4) μg/kg/min for 0–20 minutes and 51 (SD 7) μg/kg/min for 20–40 minutes), twenty received midazolam (35 μg/kg + 2.54 (SD 0.2) μg/kg/min for 0–20 minutes and 1.35 (SD 0.2) μg/kg/min for 20–40 minutes) and ten patients received saline infusion only. The forearm vasoconstriction in response to the spinal anaesthesia was measured by strain gauge plethysmography. Spinal anaesthesia lowered systolic and diastolic blood pressure by 18 (SED 4) mmHg and 9 (SED 2) mmHg respectively. (SED = standard error of the difference.) This was associated with a 32% decrease in mean forearm blood flow. Propofol and midazolam caused similar additional reductions in systolic and diastolic blood pressure (10 (SED 4) mmHg and 4 (SED 2) mmHg) and a decrease in heart rate (P< 0.005), but forearm vasoconstriction was not altered. In the control group, however, forearm vasoconstriction increased during 40 minutes in theatre (P<0.05). Recovery from propofol was far more rapid than after midazolam and was virtually complete in ten minutes. This was reflected by an increase in blood pressure and in forearm vasoconstriction in the recovery period.
Neurological Monitoring during Anaesthesia and Surgery
Authors: McMeniman W. J. , Purcell G. J.
Published: January 2019

The ability to monitor the electrical activity of the central nervous system and to record responses to stimulation allows for a more immediate assessment of the functional integrity of the nervous system during anaesthesia than do conventional techniques. These monitoring methods, however, have been slow to find acceptance in clinical practice. The reasons include the difficulty with standardization and reproducibility of results from such monitoring techniques as the electroencephalogram (EEG) and evoked potentials, along with the level of expertise necessary for accurate interpretation of the voluminous data collected.

Anaesthetic agents along with variations in physiological parameters can markedly alter the recordings not to mention the influence of diathermy, other electrical devices, muscle activity and artifact.

Because of these inherent difficulties, most anaesthetists still rely on optimising such physiological parameters as arterial, venous and intracranial pressures, oxygen and carbon dioxide tensions, to ensure the functional integrity of the nervous system. This brief review explores the potential areas of application of electrophysiologic monitoring in surgery and anaesthesia. 1–5
An Assessment of Postoperative Oxygen Therapy in Patients with Fractured Neck of Femur
Authors: Dyson A. , Henderson A. M. , Chamley D. , Campbell I. D.
Published: January 2019

Arterial oxygen tension was studied in sixty patients with fractured neck of femur. The mean preoperative arterial oxygen tension was 63.7 mmHg (SD 12.8). Half of the patients received nasal oxygen for five days postoperatively. In these patients, mean arterial oxygen tension was greater at all times than preoperative values, and exceeded values in those not receiving oxygen in whom no change in oxygen tension occurred until an increase on the fifth postoperative day.
Inspired Oxygen and Nitrous Oxide Concentrations in Volunteers during Nitrous Oxide Sedation with a Hudson Mask
Authors: Anderson B. J. , Dyson A. , Henderson A. M.
Published: January 2019

Ten volunteers were given varying ratios of oxygen and nitrous oxide at 4,6 and 8 litres per minute using a Hudson mask delivery system. Maximum and minimum inspired oxygen concentrations, maximum inspired nitrous oxide concentrations and end tidal carbon dioxide concentrations were measured using the Datex Cardiocap CCI-104 monitor. Although pharyngeal oxygen fraction varies with the Hudson mask because the inspiratory flow exceeds the entrainment of the mask by a variable amount during much of the cycle, at 8 litres/minute flow with a ratio of 3 to 5, oxygen to nitrous oxide, safe levels of oxygen were delivered (range of means 26–31%) with basal nitrous oxide levels (mean maximum inspired N 2 O, 34%). When nitrous oxide sedation is used clinically, nitrous oxide must be used with consideration of safe oxygen levels. This study did not detect unsafe pharyngeal oxygen levels in the ratios investigated, where the maximum delivered nitrous oxide concentration was 75%.
The Development and Clinical Use of Patient-Controlled Analgesia
Authors: Owen H. , Mather L. E. , Rowley K.
Published: January 2019

Patient-controlled analgesia has successfully made the transition from research tool to clinical acceptability. Reliable and sophisticated patient-controlled analgesia systems are commercially available. The technique has been most used for control of postoperative pain but has been successfully used during labour, after burns and other trauma and in terminal care. Virtually every opioid has been administered by patient-controlled analgesia using almost every route of administration. It is more effective than the traditional techniques of pain control after surgery but is not automatically so. Choice of opioid and the settings chosen for demand dose and lockout interval greatly influence effectiveness. Patient-controlled analgesia requires active participation by the patient but the psychology of patient-controlled analgesia has generally been underestimated. Patient-controlled analgesia has developed empirically and many assumptions have been made; there is a need for fundamental research.
A Longitudinal Study of 100 Consecutive Admissions for Carbon Monoxide Poisoning to the Royal Adelaide Hospital
Authors: Gorman D. F. , Clayton D. , Gilligan J. E. , Webb R. K.
Published: January 2019

A longitudinal study of one hundred consecutive admissions to the Royal Adelaide Hospital for carbon monoxide poisoning was conducted from 1986 to 1989. Twenty-five patients left hospital with persistent symptoms and signs of this poisoning. Five subsequently recovered. Twenty-four other patients, who were well when they left hospital, did not attend for a review one month after discharge. Extensive neuropsychiatric testing at this time showed 32% (24 of 76) had obvious sequelae of their exposure. Overall, the frequency of neuropsychiatric sequelae in the patients who only received oxygen at atmospheric pressure was 63% (N = 8) on discharge and 67% (N = 6) on one month follow-up. The frequency of sequelae among those who were given one hyperbaric oxygen treatment only was 46% (N = 24) on discharge and 50% (N = 20) on one month follow-up. In contrast, the frequency of sequelae in patients who had two or more hyperbaric oxygen treatments was only 13% (N = 68) on discharge (P < 0.005) and 18% (N = 50) on follow-up (P < 0.005). The frequency of sequelae was also significantly greater if hyperbaric oxygen was delayed (P < 0.05). No markers of severe poisoning could be identified.
A Five-Year Prospective Analysis of the Efficacy, Safety and Morbidity of Epidural Anaesthesia Performed by a General Practitioner Anaesthetist in an Isolated Rural Hospital
Authors: Watts R. W.
Published: January 2019

During a five-year period, 324 epidurals were performed by a general practitioner anaesthetist in an isolated rural hospital. Of these 160 were for obstetric purposes, 72% in primagravida patients, the majority in early and established labour (median cervical dilatation of 3.0 cm). The median epidural insertion time was seven minutes: 80% were free of all complications, there were no dural taps and there was a failure rate of 2%.

The median visual analogue pain score (VAPS) was 8.3 prior to insertion and at peak of epidural blockade it was reduced to 0.5. Ten per cent of patients had unblocked segments, half of these were corrected and 90% of patients had even blocks.

Despite higher pain scores in the 6–10 cm cervical dilatation group, epidural analgesia was just as effective when compared to the 0.5 cm group.

Seventy-seven percent of women interviewed the day after delivery were fully satisfied with the epidural: 19% said it was considerable help, 2% some help and 2% said no help at all. During epidural caesarean section (n = 72), 75% of patients were comfortable, 17% had some discomfort and 7% required general or spinal anaesthesia.

The incidence of hypotension (systolic blood pressure < 90 mmHg), was 24.6% with a median ephedrine dose of 10 mg; however, with a greater than 20% drop in systolic blood pressure, the dose of ephedrine required to maintain blood pressure increased in a log-dose fashion.

For women who received epidurals in labour, the caesarean section rate was 25%, instrumental vaginal delivery 34% and spontaneous vaginal delivery 41%. There were no adverse neonatal outcomes.
Leukodepleted Blood Components
Authors: Thomson A. R.
Published: January 2019

The use of leukodepleted blood components may reduce some adverse effects of transfusion in certain clinical situations. This review outlines the recognised effects of contaminating passenger leucocytes, the value of leukodepleted components in preventing some of these complications, methods of leukodepletion and the current recommendations for use of these components.
Efficacy of Pressure Support in Compensating for Apparatus Work
Authors: Bersten A. D. , Rutten A. J. , Vedig A. E.
Published: January 2019

Breathing through an endotracheal tube, connector, and ventilator demand valve imposes an added load on the respiratory muscles. As respiratory muscle fatigue is thought to be a frequent cause of ventilator dependence, we sought to examine the efficacy of five different ventilators in reducing this imposed work through the application of pressure support ventilation.

Using a model of spontaneous breathing, we examined the apparatus work imposed by the Servo 900-C, Puritan Bennett 7200a, Engstrom Erica, Drager EV-A or Hamilton Veolar ventilators, a size 7.0 and 8.0 mm endotracheal tube, and inspiratory flow rates of 40 and 60 l/min. Pressure support of 0, 5, 10, 15, 20 and 30 cm H2O was tested at each experimental condition.

Apparatus work was greater with increased inspiratory flow rate and decreased endotracheal tube size, and was lowest for the Servo 900-C and Puritan Bennett 7200a ventilators. Apparatus work fell in a curvilinear fashion when pressure support was applied, with no major difference noted between the five ventilators tested. At an inspiratory flow rate of 40 l/min, a pressure support of 5 and 8 cm H2O compensated for apparatus work through size 8.0 and 7.0 endotracheal tubes and the Servo 900-C and Puritan Bennett 7200a ventilators. However, the maximum negative pressure was greater for the Servo 900-C.

The added work of breathing through endotracheal tubes and ventilator demand valves may be compensated for by the application of pressure support. The level of pressure support required depends on inspiratory flow rate, endotracheal tube size, and type of ventilator.
Insertion of the Laryngeal Mask Airway—A Prospective Study of Four Techniques
Authors: Brimacombe J. , Berry A
Published: January 2019

The standard insertion technique (ST 0) for laryngeal mask airway insertion was compared to three alternative techniques in 120 patients. The alternative techniques included insertion using the standard approach, but with the cuff either semi-inflated (ST 0.5) or fully inflated (ST 1.0), and a non-standard approach using a back-to-front technique (like a Guedel airway) and with the cuff fully deflated (T 180). Successful insertion was judged by fibreoptic positioning and function. The results confirmed that the ST 0 and T 180 were superior to ST 0.5 and ST 1.0 in terms of fibreoptic positioning (P<0.02) and that insertion with the cuff deflated (ST 0 and T 180) resulted in fewer insertion failures than with the cuff inflated (ST 0.5 and ST 1.0) (P<0.05). Insertion with the LMA back-to-front with the cuff deflated produced similar fibreoptic and functional results to the standard technique. In 23%, however, there was some residual rotation of 25–90% to the coronal plane.
The Sprotte Needle and Post Dural Puncture Headache following Caesarean Section
Authors: Ross A. W. , Greenhalgh C. , McGlade D. P. , Balson I. G. , Chester S. C. , Hutchinson R. C. , Ashley J. E.
Published: January 2019

One hundred and forty-four patients receiving subarachnoid anaesthesia for caesarean section were prospectively analysed for quality of anaesthesia and the occurrence of post dural puncture headache (PDPH). Anaesthesia was administered via 24 gauge Sprotte (n = 104) and 26 gauge Quincke (n = 40) needles using hyperbaric bupivacaine 0.5% with morphine 0.2 mg. Anaesthesia was successful in 103 patients with the Sprotte needle and 38 patients with the Quincke needle, and the operating conditions were considered to be excellent. Of the 104 patients in the Sprotte needle group there were ten with PDPH (9.6%), two of which were considered severe. Of the 40 patients in the Quincke needle group there were eight with PDPH (20%), three of which were considered severe. Despite the lower incidence of headache in the Sprotte needle group, this was not statistically significant (P>0.05), due to the difference in population size. We conclude that the 24 gauge Sprotte needle is associated with a comparatively low but clinically relevant incidence of headache in the obstetric population.
Apnoea and Oximetric Desaturation in Patients Receiving Epidural Morphine after Gastrectomy: A Comparison of Intermittent Bolus and Patient Controlled Administration
Authors: Nozaki-Taguchi N. , Oka T. , Kochi T. , Taguchi N. , Mizuguchi T.
Published: January 2019

The number of apnoeic episodes and arterial oxygen desaturations were measured preoperatively and for sixty hours postoperatively in twenty ASA status 1–2 patients scheduled for elective gastrectomy. Monitoring included continuous pulse oximetry, respiratory inductive plethysmography and repeated arterial blood gas analysis. The number and magnitude of apnoeas and desaturation episodes were compared between two postoperative analgesic regimens of epidural morphine; intermittent bolus injection (Group B, n = 10), and patient controlled administration with continuous infusion (Group P, n = 10). Morphine dose, PaCO2 and mean SpO2 values were similar between the two groups. Although the number of central apnoeas with SpO2<90% was greater in Group B, other episodes of apnoea or desaturation were similarly seen preoperatively. In the postoperative period, central apnoeas with SpO2<90% were significantly increased in Group B, while no change was seen in Group P. Apnoeas with SpO2<80% were only seen in Group B. We conclude from these results that postoperative apnoeas and episodic desaturations are greatly influenced by the different modes of opioid administration.
A Rabbit Model for the Evaluation of Epidurally Administered Local Anaesthetic Agents
Authors: Hughes P. J. , Doherty M. M. , Charman W. N.
Published: January 2019

A rabbit model is described for the evaluation of epidurally administered local anaesthetic agents. The technique involves a single injection via the readily identified lumbosacral space in conscious rabbits, with the epidural space being identified by a modified loss-of-resistance technique. The endpoints used to assess pharmacodynamic responses of the rabbit model were (I) sensory loss, (2) loss of weight-bearing ability, and (3) flaccid paresis. The model was further characterised by investigation of endpoint responses to changes in injection volume (0.1-0.25 ml/kg) and concentration of administered lignocaine solutions (0.5 to 2%). From these studies, a volume of 0.2 ml/kg was chosen as a standard dose and a subsequent comparison between different agents undertaken. The rank order for the onset of action, duration of effect and the observed pharmacokinetic profiles after epidural administration of 2% lignocaine, 2% lignocaine with adrenaline (1:200,000) or 0.5% bupivacaine solutions are broadly consistent with human clinical data. These data indicate that the rabbit is a simple (albeit limited) model for the screening evaluation of epidurally administered local anaesthetic agents.
A Comparison of Three Ported Cannulae Available in New Zealand
Authors: Treuren B. C. , Yusuf A. , Galletly D. C. , Robinson B. J.
Published: January 2019

A comparison was made of the three 22-gauge ported intravenous cannulae available in New Zealand—Venflon 2,® Vasofix Braunule® and Insyte.® All cannulae performed satisfactorily in terms of overall success of cannulation although significant differences were apparent in both clinical and laboratory performance. Anaesthetists’ clinical preference was for Insyte and Venflon 2 brands, perceiving these to have greater ease of handling and better packaging. In a series of laboratory studies, Vasofix was found to have the highest flowrate, the fastest time to flashback and the lowest valve opening pressure. Insyte required the least force of penetration. Venflon 2 had the greatest margin of safety between pressure to inject through the port and pressure required to blow the syringe/port assembly apart. Potential problems were identified with the Insyte port valve mechanism.
The Stethoscope: Applications and Limitations– An Analysis of 2000 Incident Reports
Authors: Klepper I. D. , Webb R. K. , Van Der Walt J. H. , Ludbrook G. L. , Cockings J.
Published: January 2019

The first 2000 incidents reported to the Australian Incident Monitoring Study (AIMS) were analysed with respect to the role of the oesophageal or precordial stethoscope as a continuous monitor. There were 1099 of the 1256 incidents during general anaesthesia in which one might have been used in this way, but use was reported in only 65 cases (5%), predominantly during paediatric cases. In only one report, a cardiac arrest, was the stethoscope the first to detect the incident.

In a theoretical analysis it was considered that the stethoscope, used on its own for continuous monitoring, could have detected 54% of the 1256 incidents (almost 25% before any potential for organ damage), had they been allowed to evolve. However, AIMS data suggest that the actual yield using a stethoscope as a continuous monitor may be much lower than this, and that even the use of a “mobile” stethoscope can not be relied upon to detect oesophageal or endobronchial intubation.

These reports confirm that there is limited use of the stethoscope for continuous monitoring in current anaesthetic practice in Australia; it has been superseded by the sophisticated electronic monitors now available. However, in areas with limited resources continuous auscultation with a stethoscope remains a basic requirement.
Pneumothorax: An Analysis of 2000 Incident Reports
Authors: Williamson J. A. , Webb R. K. , Van Der Walt J. H. , Runciman W. B.
Published: January 2019

Eighteen (1%) of the first 2000 incidents reported to the Australian Incident Monitoring Study (AIMS) involved actual or suspected pneumothoraces; 17 were confirmed. Eleven of the patients were seriously ill beforehand. Four developed tension pneumothoraces, and in 2 incidents (1 tension) the pneumothoraces were bilateral. Nine of the 17 were iatrogenic; 6 (35%) followed neck vein cannulation, and 3 (18%) were surgical complications of tracheotomies. No death was attributed to a pneumothorax.

In 8 of the 17 incidents, diagnostic delay or difficulties occurred. Contributing factors identified included urgency, distorted anatomy, failure to check, and haste on the part of the anaesthetist. Desaturation detected by pulse oximetry and hypotension detected by invasive blood pressure monitoring warned the anaesthetist on 2 occasions each.

Indications for central vein cannulation or trans-tracheal airway manoeuvres must be firm. Such procedures should always be followed by a closely scrutinised erect chest X-ray as soon as practicable. The possibility of a pneumothorax must always be considered when unexpected cardiorespiratory deterioration occurs.
Physical Injuries and Environmental Safety in Anaesthesia: An Analysis of 2000 Incident Reports
Authors: Singleton R. J. , Ludbrook G. L. , Webb R. K. , Fox M. A. L.
Published: January 2019

Of the first 2000 incidents reported to the Australian Incident Monitoring Study, 56 (3%) involved environmental hazards or injuries to patients or staff. There were 17 cases of oral trauma (14 of tooth loss or damage, in 7 of which poor dentition played a role), 10 incidents involving problems with the operating table, 6 cases of skin or eye damage and 6 cases in which an electrical hazard was identified. Five incidents occurred during transport, and there were 4 cases of monitor induced trauma, 4 “needlestick” injuries and 4 miscellaneous incidents. Recommendations are made for trying to avoid or reduce the incidence of some of these problems.
Evaluation of Safety Procedures in Anaesthesia and Intensive Care
Authors: Clayton D. G. , Barker L. , Runciman W. B.
Published: January 2019

A study was conducted to determine the ability of junior anaesthetists to check the anaesthetic machine, demonstrate a knowledge of a multifunction monitor and a defibrillator, and know the hospital fire drill. The subjects were 38 junior anaesthetists working in a large multi-disciplinary teaching hospital. 45% were able to check the anaesthetic machine according to the guidelines of the Australian and New Zealand College of Anaesthetists, and 16% had a complete working knowledge of the monitor. All subjects could use the defibrillator but only 24% could adequately solve the problem of malfunction. Only one subject had a working knowledge of the fire drill; excluding knowledge of the fire drill only 3 subjects (8%) satisfactorily completed all aspects of the assessment. As a result of this study structured checking routines are being introduced into anaesthetic teaching and practice and a similar multi-center study of specialist anaesthetists is being planned.
A Survey of Personal and Professional Attitudes of Intensivists to Organ Donation and Transplantation
Authors: Pearson I. Y. , Zurynski Y.
Published: January 2019

A questionnaire survey was carried out to examine the attitudes and practices of Australian and New Zealand intensivists with regard to brain death and organ donation. A return rate of 82.5% was achieved. Fifty-eight per cent had written evidence of their own wishes to donate organs and 94% would agree to donation from a dependent. At least one intensivist is involved in certifying brain death on 95% of occasions. Intensivists are involved in the request for organ donation over 90% of the time although one-third do not believe that it is their role to request organ donation. Although two-thirds believe that the family should always be approached for organ donation, another 52 out of 254 indicated that it was their (the intensivist's) role to decide if families should be asked for organ donation. Possible reasons for not requesting are language or other communication problems, perceptions of cultural differences and degrees of family distress. Twenty per cent of respondents do not provide haemodynamic support before brain death confirmation.

Australian and New Zealand intensivists overwhelmingly support the concept of brain death, current methods of confirmation of brain death, organ donation and transplantation. Possible reasons behind loss of potential donors include decisions not to resuscitate both before and after brain death is confirmed. Perceptions of family grief and cultural differences clearly inhibit requests for organ donation. A very few units have an effective policy on approaching families about organ donation. Intensivists have almost exclusive control over requests for organ donation and thus bear a full professional responsibility for this element of hospital practice.
Donor Families’ Experience of Organ Donation
Authors: Douglass G. E. , Daly M.
Published: January 2019

This retrospective study surveyed families who consented to organ donation in the State of Queensland, Australia, from January 1991 to December 1992 inclusive, and evaluated their experience of the organ donation process. The survey questioned families in relation to the preparation they received, their understanding of brain death, the request process, influencing factors, and post donation follow-up. One hundred and eight families consented to organ donation over this 24-month period. Twelve families of paediatric donors under the age of twelve years were excluded, and twelve families were not able to be contacted. Of the remaining 84 families, 42 participated in this study.

Overall the study results indicated a positive attitude towards the organ donation process. The majority of families did not find the process stressful and indicated that they were provided with sufficient information and preparation, and that the request was made in a sensitive manner. A few important issues and areas for improvement were highlighted: in particular, the need for families to have an opportunity to view the body after procurement, and the importance of counselling throughout and after the donation process.
Bronchoscopic Insufflation of Room Air for the Treatment of Lobar Atelectasis in Mechanically Ventilated Patients
Authors: Van Heerden P. V. , Jacob W. , Cameron P. D. , Webb S.
Published: January 2019

Segmental and lobar pulmonary atelectasis is a common occurrence in mechanically ventilated patients. Standard therapy for atelectasis relies on positive pressure ventilation, positive end expiratory pressure (PEEP), tracheobronchial toilet and regular chest physiotherapy. Various adjuncts to physiotherapy such as bronchoscopic clearance of secretions have not proved to be of additional benefit. Bronchoscopic clearance of secretions followed by insufflation of room air at 30 cm H2O into the atelectatic segment was employed on ten occasions in mechanically ventilated patients. Rapid re-expansion of the collapsed segment or lobe occurred in seven out of the ten treatments.
Parental Presence at Induction of Anaesthesia: A Survey of N.S.W. Hospitals and Tertiary Paediatric Hospitals in Australia
Authors: Baines D. , Overton J. H.
Published: January 2019

We undertook a survey of N.S.W. hospitals and tertiary paediatric hospitals in other States to determine their practice in relation to parental presence at induction of anaesthesia of children. There were 135 responses to 174 questionnaires. Twenty-one indicated that no children were anaesthetized at their institution and one was inadequately filled out. One hundred and thirteen questionnaires were assessed. Only 44% of departments had an official policy on parental attendance. A quarter of all hospitals described their facilities as entirely suitable, and a half compromised to allow parents to be present. The remaining quarter described their facilities as unsuitable. Overall, two-thirds of hospitals never or only sometimes had parents present at induction, and this applied equally to daystay patients and inpatients. Tertiary hospitals were more likely to have parents present, however they were more likely to have suitable facilities.

The most common reason cited for parental attendance was parental expectation of being present, closely followed by the individual anaesthetist's philosophy. The most common reason for parents not attending was the individual anaesthetist's philosophy, followed by inadequate staffing.
Maxima and Bain Breathing Systems Compared in Controlled Ventilation
Authors: Miller D. M.
Published: January 2019

The Maxima is a new universal breathing system, which, despite its being valveless, functions with near maximal efficiency in spontaneous and controlled ventilation.

It was compared to the Bain system in controlled ventilation by adjusting fresh gas flows (V̇F) to achieve an endtidal CO2 of 5% in 40 patients aged from one to seventy-six years. They received a combined regional and general anaesthetic technique. The overall V̇F requirement of the Maxima system was: weight in kg x 35 ml.min−1 .kg−1 + 1160 ml.min−1; the Bain system required V̇F of: weight in kg x 42 ml.min-1 .kg-1 + 2070 ml.min−1. The mean V̇F requirement for the Bain system was greater by 45%. Of these forty patients, the results from the twenty-four adult patients weighing 50 kg or more gave the respective V̇F requirements for the Maxima and Bain systems of 52 and 71 ml.min−1 .kg−1.

In a separate study using twenty-nine patients, the fractional utilization of fresh gas (FU) (or VAe/VF where VAe = effective alveolar ventilation) in the Maxima and Bain systems was shown to be 0.94 and 0.71 respectively.
Detection of Cerebral venous Desaturation by Continuous Jugular Bulb Oximetry following Acute Neurotrauma
Authors: Lewis S. B. , Myburgh J. A. , Reilly P. L.
Published: January 2019

A prospective observational study was performed to assess the reliability of fibreoptic oximetric catheters and to identify the incidence and causes of jugular bulb oxygen desaturation in patients with acute closed head injury. There were twenty- five patients (30± 16 years) with GCS ≤8 in this study.

Jugular bulb oximetry, mean arterial pressure, intracranial pressure, end-tidal CO2 and pulse oximetry were monitored continuously. Catheter calibration against a laboratory oximeter was performed post insertion and thereafter eight-hourly. Cerebral venous desaturation was defined as a jugular bulb oxygen saturation <55% of >10 minutes duration. There was a poor correlation for the first in vivo calibration (r2 = 0.602, P<0.001, n=25). Thereafter a close correlation between jugular bulb catheter and oximetry values was demonstrated (r2 = 0.868, P<0.001, n=205). Forty-two episodes of jugular bulb oxygen desaturation of 88 minutes mean duration (range 10 to 555) were observed. 83% occurred within 48 hours following injury. Hypocapnia was associated in 45% of episodes; hypoperfusion in 22%; raised ICP in 9% and a combination of the above in 24%.

Validation with a laboratory oximeter is essential prior to continuous jugular bulb oximetry. Sustained episodes of cerebral venous desaturation are frequent within the first 48 hours following acute head injury. Factors such as hypocapnia and cerebral hypoperfusion that primarily reduce cerebral blood flow are predominant.
Sacral Intervertebral Approach for Epidural Anaesthesia in Infants and Children: Application of “Drip and Tube” Method
Authors: Kumagai M. , Yamashita M.
Published: January 2019

Sacral intervertebral approach to the epidural space was introduced as an alternative to the caudal approach in infants and children in 1987. We performed single-shot epidural anaesthesia in 200 infants and children with this approach using the “drip and tube” method for identification of the epidural space. Identification of the epidural space was marked by commencement of dripping in the chamber of a micro-drip infusion set which was connected to the epidural needle. With the IV extension tube, local anaesthetic solution was injected by the “immobile needle” technique. Overall success rate of the block was 96%. This approach to the epidural space is anatomically easy in infants and children, and application of our “drip and tube” method might make the paediatric single-shot epidural anaesthesia safer and more successful.
The Application of EMLA and Glyceryl Trinitrate Ointment Prior to Venepuncture
Authors: Michael A. , Andrew M.
Published: January 2019

The efficacy of EMLA® cream combined with glyceryl trinitrate (GTN) ointment was assessed by a double-blind prospective study. Adult female patients were randomly allocated to receive either EMLA 1 ml or 2 ml combined with GTN 2 mg, or EMLA 2 ml only. The difference in pain scores between the three groups was not statistically significant. When GTN was used with EMLA, the quality of the veins was superior and aided intravenous cannulation. There were no significant side-effects.

It is concluded that if GTN is used with EMLA, the dose of EMLA can be reduced and intravenous cannulation is technically easier compared with EMLA alone.
Respiratory Variables during Thoracotomy for PDA Ligation
Authors: Puri G. D. , Hariwir Singh , Chari P. , Gujral J. S.
Published: January 2019

Physiological deadspace fraction of tidal volume (VD/VT), arterial to end-tidal carbon dioxide tension differences [P(a-é)CO2], arterial oxygen tension (PaO2) and respiratory system compliance were studied in twenty patients with patent ductus ateriosus scheduled for multiple ligation and transfixation through posterolateral thoracotomy under general anaesthesia with controlled ventilation. The study period was divided into six stages: stage 1—supine posture under anaesthesia, stage 2—lateral posture before start of surgery, stage 3—after chest opening before lung manipulation, stage 4—after ductus ligation and lung re-expansion before chest closure, stage 5—lateral posture, chest closed, stage 6—supine stage before reversal.

There was a significant (P<0.01) increase of VD/VT on attaining the lateral posture. The fraction decreased significantly (P<0.05) on opening of the chest (stage 3) and subsequently increased at stage 4. There was no significant change in mean P(a-é)CO2 at various stages of thoracotomy. PaO2 fell significantly on opening of the chest and was lowest before chest closure (stage 4). PaO2 increased following chest closure but was still significantly lower than the pre-surgical supine stage. Respiratory system compliance was lowest at stage 4.

Changes in deadspace fraction VD /VT do not correspond favourably to arterial oxygen tensions during posterolateral thoractomy.
The Influence of Surgery on Cytokines in Patients with Intra-Abdominal Sepsis
Authors: Hammond J. M. J. , Potgieter P. D.
Published: January 2019

The cytokine cascade which is triggered by severe sepsis may contribute to progressive organ dysfunction and death from sepsis. This cascade may be accentuated by surgery for sepsis and pre-treatment with cytokine blockers could possibly ameliorate the response. This prospective controlled study determined the effect of surgery in 11 haemodynamically stable patients undergoing laparotomy for intra-abdominal sepsis. Serum levels of endotoxin, IL-1, IL-6, IL-8 and TNF-α were determined; blood cultures, features of systemic inflammatory response, and organ dysfunction were monitored over the perioperative period. There was considerable variation in the serum cytokine levels. The preoperative IL-6 levels were significantly elevated in the septic patients and a threefold increase in IL-6 levels occurred in both groups postoperatively. An increase in TNF-α did not achieve significance because of high levels in control patients with cancer. Cytokine release which occurs during abdominal surgery is increased in patients with intra-abdominal sepsis.
Brain and Blood Concentrations of Propofol after Rapid Intravenous Injection in Sheep, and Their Relationships to Cerebral Effects
Authors: Ludbrook G. L. , Upton R. N. , Grant C. , Gray E. C.
Published: January 2019

The time-course of propofol concentrations in the blood and brain following rapid administration of three doses were examined using a sheep preparation and regional pharmacokinetic techniques. These were compared to the time-course of cerebral effects of propofol reported previously. There were marked differences between the time-course of propofol concentrations in arterial blood and the brain, with a close relationship between the time-course of brain concentrations and effects on depth of anaesthesia and CBF. There was evidence that the effect of propofol on cerebral blood flow altered its own rate of elution from the brain. Hysteresis between arterial propofol concentrations and cerebral effects following rapid IV administration therefore appears to have a pharmacokinetic basis, and conventional compartmental pharmacokinetic analysis using blood concentrations alone may fail to accurately predict the time-course of both brain propofol concentrations and depth of anaesthesia.
Prophylactic Administration of Histamine 1 and/or Histamine 2 Receptor Blockers in the Prevention of Heparin- and Protamine-Related Haemodynamic Effects
Authors: Kanbak M. , Kahraman S. , Celebioglu B. , Akpolat N. , Ercan S. , Erdem K.
Published: January 2019

The efficacy of prophylactic administration of H1 and H2 receptor blockers to prevent adverse haemodynamic responses to heparin and protamine was studied. The control group (n=10) received no histamine receptor blocker, group H1 (n=10) received oral terfenadine 60 mg, group H2 (n=10) received oral ranitidine 300 mg, and group H1+H2 (n=10) received both terfenadine and ranitidine on the night before the operation and on call to the operating room. Heparin sulphate 300 U/kg was injected directly into the right atrium, and protamine hydrochloride was administered at the conclusion of bypass over at least three minutes through a peripheral route. Following the injection of heparin, plasma histamine-like activity (H-LA) was increased significantly in all four groups. While systolic, diastolic, mean arterial and central venous pressures were decreased significantly in the control group, no significant changes were observed in the H1 and H2 groups. Protamine infusion did not lead to an increase in H-LA. Prophylactic administration of histamine receptor blockers (H1 or H2) attenuated the heparin-induced adverse haemodynamic response but did not change the protamine-related haemodynamic effects. Factors other than histamine may play a major role in protamine induced cardiovascular changes.
Anaesthesia Information—What Patients Want to Know
Authors: Garden A. L. , Merry A. F. , Holland R. L. , Petrie K. J.
Published: January 2019

We developed and introduced into clinical practice a leaflet to improve the delivery of information to patients before obtaining their consent to anaesthesia. The amount of information needs to be what a “reasonable” patient thinks appropriate; therefore we tested patients’ responses to three levels of information: “full” disclosure, “standard” disclosure (as contained in our leaflet) and “minimal” disclosure. Forty-five patients scheduled to undergo cardiac surgery were enrolled in the study. None of the information sheets caused a significant change in state anxiety score and only the “full” disclosure significantly increased knowledge about anaesthesia (P=0.016). All leaflets were easy to understand. When only one leaflet was provided 64–73% of patients thought the content was “just right”, whereas when all three leaflets were viewed together, 63% of patients thought the “minimal” leaflet withheld too much information.
Uterine Rupture and Scar Dehiscence. A Five-Year Survey
Authors: Lynch J. C. , Pardy J. P.
Published: January 2019

A review of the medical records from two public hospitals in Sydney was undertaken to determine the incidence of this uncommon complication. Twenty-seven cases of uterine rupture were reported out of 31,115 deliveries with an incidence of 0.086% (versus 0.05% in the current literature). The incidence associated with previous caesarean section was 0.038% (versus 0.8% in the current literature).

Predisposing and associated factors in this review were similar to those reported by others.

There was no maternal mortality in our series but the fetal mortality rate was 5 out of 27 cases. Uterine ruptures in the midtrimester were associated with high rates of maternal morbidity and fetal loss.

Forty-eight per cent of patients with uterine rupture received epidural analgesia. The associated factors and outcomes are discussed.

The current literature is reviewed in relation to this high-risk group of patients.
Acute Haemodynamic Effects of Sodium Bicarbonate Administration in Respiratory and Metabolic Acidosis in Anaesthetized Dogs
Authors: Tanaka M. , Nishikawa T.
Published: January 2019

Twenty-seven halothane-anaesthetized, mechanically ventilated adult mongrel dogs were randomly assigned to either respiratory acidosis group [pHa 7.22 (0.03, SD), PaCO2 9.6 (1.1) kPa, base excess –0.5 (1.4) mmol.l–1, n=9], metabolic acidosis group [pHa 7.20 (0.05), PaCO2 5.5 (0.4) kPa, base excess –11.1 (2.1) mmol.l–1, n=9], or non-acidosis group [pHa 7.37 (0.07), PaCO2 5.2 (0.4) kPa, base excess –1.1 (1.5) mmol.l–1, n=9]. Respiratory acidosis and metabolic acidosis were induced by decreasing respiratory rate and continuous infusion of 2 mmol.l–1 hydrochloric acid, respectively. Sodium bicarbonate solution 1 mmol.kg–1 was injected into the right atrium over five seconds when haemodynamic stability was obtained.

In all three groups, acute administration of sodium bicarbonate produced transient decreases in mean arterial pressure and RV dP/dtmax, and transient increase in right atrial pressure 30 seconds after injections, but these variables returned to the pre-injection values by the end of the three minutes observation period. Although no significant differences were seen in haemodynamic variables among the three groups at 30 seconds, one and three minutes, maximum reductions in both RV dP/dtmax and PBF in the metabolic acidosis group (260 (143) mmHg.s–1 and 0.38 (0.26) l.min–1) were significantly greater than those in the non-acidosis group (127 (34) mmHg.s–1 and 0.08 (0.09) l.min–1; P<0.05).
Objective Evaluation of the Difficulty of Endotracheal Intubation. A Comparative Study of Two Different Laryngoscope Blades
Authors: Papageorgiou E. , Kokkinis K. , Goumas P. , Mochloulis G. , Alexopoulos C.
Published: January 2019

A method for objective evaluation of the difficulty of endotracheal intubation is described. Our data indicate that the angle formed by the light-beam axis of the laryngoscope blade and the laryngotracheal axis, which we call “angle ϕ”, is analogous to the degree of difficulty of endotracheal intubation. Using this method, we compared the effectiveness of a standard Macintosh and a modified bevelled Macintosh blade in 27 tracheostomized Intensive Care Unit patients under general anaesthesia. Statistical analysis of our results indicate that the bevelled blade significantly facilitates endotracheal intubation.
Informed Consent—Survey of Auckland, N.Z. Anaesthetists’ Practice and Attitudes
Authors: Chapman I. H.
Published: January 2019

Auckland anaesthetists were surveyed. Of these, 68% obtain written informed consent, 67% are familiar with the New Zealand Medical Council's statement on informed consent, and 57% believe that they conform with this statement in their practice. 4% of anaesthetists always warn their patients of the possibility of death, 9% never do. 87% warn of minor complications such as vomiting, 28% warn of possible awareness, 27% of possible paralysis with spinal or epidural. 83% felt that some form of risk-disclosing anaesthetic information leaflet would be of value for elective patients. After perusing a proposed information leaflet, 40% answered “yes” they would be happy for it to be combined with the non-risk-specific anaesthetic information currently given to patients, 23% answered “yes, with reservations”, 18% answered “yes, if modified first”, 13% “no, only if the patient asks to know more about risks”, and 5% “no, not to any patient”.
Anaesthetic Considerations for Children Undergoing Stereotactic Radiosurgery
Authors: Baker K. C. , Isert P. R.
Published: January 2019

An anaesthetic case report of children undergoing stereotactic radiosurgery is presented, with a review of the inherent unique anaesthetic challenges. Twelve stereotactic radiosurgery procedures performed at The Prince of Wales Hospital, Sydney, were retrospectively reviewed. Despite differences in approach by individual anaesthetists to managing these children, an overall safe sequence may be evolved.

The use of stereotactic radiosurgery for paediatric neuropathology is reviewed. The potential anaesthetic problems related to the paediatric patient and the peculiarities of the procedure are discussed and related to our series.
Inhalational Induction with Sevoflurane in an Adult with Severe Complex Central Airways Obstruction
Authors: Watters M. P. R. , Mckenzie J. M.
Published: January 2019

Sevoflurane is a newly available volatile anaesthetic agent which is suitable for inhalational induction of anaesthesia. Due to concerns about obstructing the upper airway as anaesthesia deepens, its use has until now been avoided in patients with upper airway obstruction. We used its smooth induction and recovery properties however to anaesthetize a patient with central airway obstruction and coexistent ischaemic heart disease. Sevoflurane proved to be a very satisfactory agent in this situation.
Hypoglossal Neuropraxia following Endotracheal Intubation
Authors: Venkatesh B. , Walker D.
Published: January 2019

A case of hypoglossal nerve neuropraxia following elective drainage of bilateral chronic subdural haematomas is described. We postulate that the cause of neuropraxia was inadvertent extubation of the trachea with the cuff inflated, leading to compression and stretch of the nerve against the greater horn of the hyoid bone. The literature on cranial nerve palsies following endotracheal intubation is reviewed.
Who’s Tweeting About the President? What Big Survey Data Can Tell Us About Digital Traces?
Authors: Pasek Josh , McClain Colleen A. , Newport Frank , Marken Stephanie
Published: January 2019

Researchers hoping to make inferences about social phenomena using social media data need to answer two critical questions: What is it that a given social media metric tells us? And who does it tell us about? Drawing from prior work on these questions, we examine whether Twitter sentiment about Barack Obama tells us about Americans’ attitudes toward the president, the attitudes of particular subsets of individuals, or something else entirely. Specifically, using large-scale survey data, this study assesses how patterns of approval among population subgroups compare to tweets about the president. The findings paint a complex picture of the utility of digital traces. Although attention to subgroups improves the extent to which survey and Twitter data can yield similar conclusions, the results also indicate that sentiment surrounding tweets about the president is no proxy for presidential approval. Instead, after adjusting for demographics, these two metrics tell similar macroscale, long-term stories about presidential approval but very different stories at a more granular level and over shorter time periods.
Geometrical design of fractional PDμ controllers for linear time-invariant fractional-order systems with time delay
Authors: Guel-Cortez Adrián Josué , Méndez-Barrios César-Fernando , González-Galván Emilio Jorge , Mejía-Rodríguez Gilberto , Félix Liliana
Published: January 2019

This article presents a simple procedure that allows a practical design of fractional –[Formula: see text] controllers for single-input single-output linear time-invariant fractional-order systems subject to a constant time delay. The methodology is based on a geometric approach, which provides practical guidelines to design stabilizing and non-fragile PDμ controllers. The simplicity of the proposed approach is illustrated by considering several numerical examples encountered in the control literature. Moreover, with the aim of showing the performance of the PDμ over a classical PD controller, both controllers were implemented at the end of the article in an experimental test-bench consisting a teleoperated robotic system.
Pathophysiology of Ganglioside GM1 in Ischemic Stroke: Ganglioside GM1: A Critical Review
Authors: Zhang Wenchao , Krafft Paul R. , Wang Tianlong , Zhang John H. , Li Li , Tang Jiping
Published: January 2019

Ganglioside GM1 is a member of the ganglioside family which has been used in many countries and is thought of as a promising alternative treatment for preventing several neurological diseases, including cerebral ischemic injury. The therapeutic effects of GM1 have been proved both in neonates and in adults following ischemic brain damage; however, its clinical efficacy in patients with ischemic stroke is still uncertain. This review examines the recent knowledge of the neuroprotective properties of GM1 in ischemic stroke, collected in the past two decades. We conclude that GM1 may have potential for stroke treatment, although we need to be cautious in respect of its complications.