Australian and New Zealand Anaesthetic Allergy Group/ Australian and New Zealand College of Anaesthetists Perioperative Anaphylaxis Management Guidelines

Anaphylaxis is an uncommon but important cause of serious morbidity and even mortality in the perioperative period. The Australian and New Zealand College of Anaesthetists (ANZCA) with the Australian and New Zealand Anaesthetic Allergy Group (ANZAAG) have developed clinical management guidelines that include six crisis management cards. The content of the guidelines and cards is based on published literature and other international guidelines for the management of anaesthesia-related and non–anaesthesia-related anaphylaxis. The evidence is summarised in the associated background paper (Perioperative Anaphylaxis Management Guidelines [2016] www.anzca.edu.au/resources/endorsed-guidelines and www.anzaag.com/Mgmt%20Resources.aspx ). These guidelines are intended to apply to anaphylaxis occurring only during the perioperative period. They are not intended to apply to anaphylaxis outside the setting of dedicated monitoring and management by an anaesthetist. In this paper guidelines will be presented along with a brief background to their development.

Production of polyunsaturated fatty acids by polyketide synthases in both prokaryotes and eukaryotes

Polyunsaturated fatty acids (PUFAs) are essential membrane components in higher eukaryotes and are the precursors of many lipid-derived signaling molecules. Here, pathways for PUFA synthesis are described that do not require desaturation and elongation of saturated fatty acids. These pathways are catalyzed by polyketide synthases (PKSs) that are distinct from previously recognized PKSs in both structure and mechanism. Generation of cis double bonds probably involves position-specific isomerases; such enzymes might be useful in the production of new families of antibiotics. It is likely that PUFA synthesis in cold marine ecosystems is accomplished in part by these PKS enzymes.

Recruitment of hepatic NK cells by IL-12 is dependent on IFN-gamma and VCAM-1 and is rapidly down-regulated by a mechanism involving T cells and expression of Fas

NK cells have been shown to be important antitumor or antiviral effector cells in the liver. In the present study we have examined the factors that regulate the initial recruitment and subsequent fate of hepatic NK and T cells in mice treated with IL-12 or IL-2. Daily administration of IL-12 caused a rapid initial increase in NK cells followed by a subsequent decrease that coincided with an accumulation of T cells. The recruitment of hepatic NK cells by IL-12, but not the subsequent T cell infiltrate, was abrogated in IFN-gamma(-/-) mice. In contrast, daily administration of IL-2 caused a sustained increase in liver-associated NK cells that was not diminished in IFN-gamma(-/-) mice. The IL-12-induced recruitment in both hepatic NK and T cells was abrogated by in vivo treatment with anti-VCAM-1 mAbs, while treatment with anti-ICAM-1 Abs decreased only the recruitment of T cells in the IL-12-treated mice. The rapid loss of newly recruited hepatic NK cells in IL-12-treated mice did not occur in SCID mice or in B.MRL-Fas(lpr) (Fas-) and B6Smn.C3H-Fasl(gld) (FasL-) mutant mice, suggesting that T cells can actively eliminate hepatic NK cells through a Fas-dependent mechanism. These findings also imply that during the endogenous innate immune response to infectious agents or tumors or in the host response induced by cytokine therapies, the biologic effects of NK cells may be limited by T cell-mediated effects.

Continuous intraoperative noninvasive cardiac output monitoring using a new thoracic bioimpedance device

OBJECTIVES

To compare a new noninvasive bioimpedance device with the standard thermodilution method during the intraoperative period in high-risk patients undergoing oncological surgery.

DESIGN

Prospectively collected data with retrospective analysis.

SETTING

The study was undertaken at a university hospital, single institution.

PARTICIPANTS

Twenty-three selected adults undergoing extensive, ablative oncological surgery.

INTERVENTIONS

Simultaneous measurements of cardiac output by a new bioimpedance method and the standard thermodilution method during the intraoperative and immediate postoperative periods.

MEASUREMENTS AND MAIN RESULTS

The correlation coefficient between the two methods was r = 0.89, p < 0.001. Bias and precision analysis between the two techniques showed a mean bias of 0.1 L/min and SD of the bias [precision] of 1.0 L/min [95% level of agreement +2.1 L/min to -1.9 L/min]. After software enhancement, data from the last 11 monitored patients showed improved correlation between the two methods; r = 0.93, mean bias -0.1 L/min, and precision 0.8 L/min. Electrical and motion-induced interference only transiently impaired the performance of the new impedance method.

CONCLUSION

This new impedance device is a safe, reliable, clinically acceptable alternative to the invasive thermodilution method in the operating room environment.

Intraoperative maintenance of tissue perfusion prevents ARDS. Adult Respiratory Distress Syndrome

Patients undergoing prolonged, complex oncological surgery are at increased risk of developing the adult respiratory distress syndrome (ARDS) and other organ failures. Our hypothesis is that maintaining adequate tissue perfusion and oxygenation may prevent tissue hypoxia and acidosis in pulmonary, peripheral, and splanchnic microcirculations. Experimental evidence suggests that the hypoxic, acidotic endothelium stimulates the release of cytokines, kinins, and other mediators. We developed and tested an intraoperative protocol for surgical patients likely to develop ARDS and organ dysfunction; the protocol focuses on the intraoperative period but is not limited to this time. Nitroglycerin and fluids were used to maintain tissue perfusion and prevent tissue hypoxia as reflected by transcutaneous oxygen tension values. In 155 high-risk patients, none developed ARDS. We conclude that maintenance of tissue perfusion and oxygenation in high-risk surgical patients decreases the incidence of ARDS.

Doxycycline for malaria prophylaxis in Australian soldiers deployed to United Nations missions in Somalia and Cambodia

The operational effectiveness of daily doxycycline alone or combined with weekly chloroquine were assessed during deployments of Australian Defence Force personnel to malaria-endemic countries. Doxycycline was given as part of mandated disease prevention measures during United Nations missions to Somalia (900 men for 4 months) and Cambodia (600 men for 12 months over two annual rotations). In Somalia the soldiers were in an area of low endemicity and experienced only three malaria cases (one Plasmodium falciparum, two P. vivax), all occurring after returning to Australia. In Cambodia the level of malaria exposure varied greatly, resulting in eight malaria cases during the entire 2-year mission (two P. falciparum, six P. vivax). Doxycycline was generally well tolerated, with 1.7% (Somalia) and 0.6% (Cambodia) of the men requiring a change of medication to mefloquine due to adverse effects. Doxycycline is an effective chemoprophylactic agent during operational deployments when soldiers truly take it every day.

Anesthesia for thoracoscopic laser ablation of bullous emphysema

BACKGROUND

We describe the anesthetic management for a new surgical procedure: laser ablation of emphysematous bullae via thoracoscope. Although thoracoscopy is not new, this is the first description of a series of patients with bilateral, chronic lung disease who underwent long periods of one-lung ventilation (OLV) during thoracoscopic therapy.

METHODS

Twenty-six laser ablation procedures were performed in 22 patients. The patients were elderly (mean age 63 yr) with a large incidence of coexisting cardiovascular disease. Most required chronic home oxygen therapy. Patients were monitored invasively, and hemodynamic data were recorded every 5 min. Arterial blood gas analyses were performed every 15 min. Comparisons were made between three intraoperative periods: two-lung ventilation (TLV) before thoracoscopy, OLV during thoracoscopy, and TLV after thoracoscopy.

RESULTS

All patients survived the operation despite a mean OLV duration of 170 min, but several experienced serious intraoperative problems, such as hypoxemia or hypotension. Hypoxemia was treated with nondependent lung continuous positive airway pressure and dependent lung positive end-expiratory pressure. In all patients the lungs were adequately ventilated, but bronchopleural fistulae occurred upon return to TLV in every case. The resulting air leaks, often 50% of inspired tidal volume, required the use of a pressure-cycled ventilator to maintain oxygenation. Postoperative air leaks greater than 50% of inspired tidal volume usually required subsequent surgical correction, while smaller leaks resolved spontaneously. Mechanical ventilation was required for an average of 5 days. Eighty-four percent have survived at least 6 months, and nearly all survivors report symptomatic improvement.

CONCLUSIONS

Ablation of bullae appears to provide symptomatic improvement, and thoracoscopy might be better tolerated than thoracotomy, especially in patients with severe bullous emphysema.

Problems with automating anaesthetic records

A truly automated recording system is one which measures the parameters selected and requires nothing more than attaching the monitors to the patient. It should be capable of being easily and rapidly started when appropriate. The user should then be able to enter quantitative and qualitative information about drug and fluid therapy in a manner which is less distracting than the present long-hand method. A system is described which has gone a considerable way towards achieving good automated physiological monitoring. The system has not resolved the problems of data entry which must be overcome before such equipment is made available for general use. The problems of automation which we encountered are presented and some possible solutions considered.

Effects of electron mediator charge properties on the reaction kinetics of hydrogenase from Chlamydomonas

Anions modulate hydrogenase activity in cell-free preparations of Chlamydomonas reinhardtii, and this modulation is greatly influenced by the charge properties of the redox agent included to mediate electron transfer to hydrogenase. With cationic methyl viologen as the electron mediator, anions stimulate the maximum velocity of H2 production (e.g., a 320% increase in the presence of 1 M NaCl) but have little effect on the Km for methyl viologen. Conversely, when hydrogenase activity is mediated by polyanionic metatungstate or ferredoxin, H2 production is strongly inhibited by anions (e.g., 70-77% inhibition by 0.2 M NaCl). This inhibition is primarily due to a reduced affinity of hydrogenase for these mediators (as evidenced by a large increase in Km values), rather than a change in the maximum velocity of the reaction. Anions have little effect on the kinetics of hydrogenase activity mediated by zwitterionic sulfonatopropyl viologen, a redox agent with a nearly neutral net charge. These results suggest the presence of a cationic region near the active site of hydrogenase. This cationic region, probably due to lysine and/or arginine residues, may serve in vivo to facilitate the interaction between hydrogenase and ferredoxin, the polyanionic, physiological electron mediator.

One year's evaluation of a system of on-line computerisation of anaesthetic records using a computer bureau

A system for the on-line computerisation of anaesthetic records using a computer bureau is described. The requirements of the system are a keyboard and video display unit appropriately linked to the bureau's computer. The system was cheap and easy to install. It required no programming expertise from department members. Disadvantages included the need to change between two screens for data entry, a delay of over 8 months before satisfactory reports materialised for individuals or the department, congestion at peak times for data entry, excessive time spent on data entry, reluctance of the bureau to alter the format of the screens once they had been generated. The cost of the system is felt to be justified by the information provided for both accreditation requirements and for department management.