Mitigating emotional responses to stressors: coping strategies, modifiers and support

OBJECTIVE

The stressful nature of the intensive care unit (ICU) environment is increasingly well characterised. The aim of this paper was to explore modifiers, coping strategies and support pathways identified by experienced Intensivists, in response to these stressors.

METHOD

Prospective qualitative study employing interviews with Intensivists in two countries. Participants were asked how they mitigated their emotional responses to the stressors of the ICU. Audio-recordings were transcribed and analysed by all researchers who agreed upon emerging themes and subthemes.

RESULTS

A wide range of strategies were reported. Although several participants had sought professional help and all supported its utility, few disclosed accessing such help to others indicating stigma. Many felt a sense of responsibility for the well-being of other staff but identified barriers that suggest alternate support pathways are required. Further implications of these findings to training considerations are described.

CONCLUSIONS

Several approaches were described as regularly employed by Intensivists to mitigate ICU environmental stressors. Intensivists perceive themselves to have limited training to provide support to others; they also perceive stigma in seeking professional help.

Behavioural responses of Intensivists to stressors in Intensive Care

BACKGROUND

The hospital intensive care unit (ICU) environment encompasses sick patients who present for care in health crisis. Healthcare in this setting is complex, often involving the co-ordination of multiple professional teams, all under significant time pressures. The sequelae for staff interacting in this dynamic and often volatile setting are variable, depending upon their coping skillset and their familiarity with the stressors.

AIMS

The primary aim of this study was to describe and in doing so, normalize the behavioural responses expressed by ICU doctors (Intensivists) in response to stressful workplace events. The secondary aim was to identify those responses that contributed to resilience.

METHODS

A prospective qualitative study of senior Intensivists using a semi-scripted iterative interview. Data were transcribed and thematically analysed with verbatim quotations selected to support coding choices.

RESULTS

Nineteen experienced Intensivists from three sites in Australia and Israel participated. Clinicians described conscious, physiological and professional responses to stressors, including sense-making and taking time to process information with appropriate support. Two of the most important mitigation processes revealed were the use of reflective learning and preventative practice changes to prevent future errors. These were overlaid with the importance of disclosure and transparency in clinical work.

CONCLUSIONS

Repeated exposure to stressful events potentiates burnout, wherein staff no longer experience satisfaction and enjoyment in what they do. This paper presents the behavioural responses that experienced Intensivists described in relation to stressful events in the ICU, including steps taken to mitigate the effects of these events on their personal well-being.

Orthodeoxia—An Uncommon Presentation following Bilateral Thoracic Sympathectomy

We present a case of orthodeoxia (postural hypoxaemia) which resulted from a combination of lung collapse/consolidation and blunted hypoxic pulmonary vasoconstriction due to partial interruption of the sympathetic nerve supply to the lung by bilateral thoracic sympathectomy

Prognosis of patients with rheumatic diseases admitted to intensive care

Variable mortality rates have been reported for patients with rheumatic diseases admitted to an intensive care unit (ICU). Due to the absence of appropriate control groups in previous studies, it is not known whether the presence of a rheumatic disease constitutes a risk factor. Moreover, the accuracy of the Acute Physiology and Chronic Health Evaluation II (APACHE II) score for predicting outcome in this group of patients has been questioned. The primary goal of this study was to compare outcome of patients with rheumatic diseases admitted to a medical ICU to those of controls. The records of all patients admitted between 1 April 2003 and 30 June 2014 (n=4020) were screened for the presence of a rheumatic disease during admission (n=138). The diagnosis of a rheumatic disease was by standard criteria for these conditions. An age- and gender-matched control group of patients without a rheumatic disease was extracted from the patient population in the database during the same period (n=831). Mortality in ICU, in hospital and after 180 days did not differ significantly between patients with and without rheumatic diseases. There was no difference in the performance of the APACHE II score for predicting outcome in patients with rheumatic diseases and controls. This score, as well as a requirement for the use of inotropes or vasopressors, accurately predicted hospital mortality in the group of patients with rheumatic diseases. In conclusion, patients with a rheumatic condition admitted to intensive care do not do significantly worse than patients without such a disease.

The role of Vitamin B12 in the critically ill--a review

Vitamin B12 is an essential micronutrient, as humans have no capacity to produce the vitamin and it needs to be ingested from animal proteins. The ingested Vitamin B12 undergoes a complex process of absorption and assimilation. Vitamin B12 is essential for cellular function. Deficiency affects 15% of patients older than 65 and results in haematological and neurological disorders. Low levels of Vitamin B12 may also be an independent risk factor for coronary artery disease. High levels of Vitamin B12 are associated with inflammation and represent a poor outlook for critically ill patients. Treatment of Vitamin B12 deficiency is simple, but may be lifelong.

Successful Introduction of a Daily Checklist to Enhance Compliance with Accepted Standards of Care in the Medical Intensive Care Unit

We introduced a simple checklist to act as an aid to memory for our junior medical staff to ensure that every patient in the intensive care unit (ICU) received every appropriate element of a bundle of care every day. The checklist was developed in consultation with our junior doctors and was designed to be completed every morning for every patient by the junior doctor reviewing the patient. The completed checklist was then checked again by the attending intensivist on the main daily ward round to ensure all the appropriate elements of the checklist had been applied to the patient. It was also noted each day which of the elements of the checklist had been forgotten and was therefore prompted to be completed by use of the checklist. Of the 75 patients surveyed there were 99 occasions, in 48 patients, when the checklist detected a forgotten element of the bundle of care (i.e. in 64% of patients). There was a decrease in the incidence of missed elements of the bundle of care the longer the patient stayed in the ICU. Types of missed elements varied with the duration of the ICU stay. We found that the introduction of a simple checklist, developed in collaboration with the junior medical staff who would be using the checklist every day in the ICU, resulted in the detection and correction of missed elements of a bundle of care we had previously introduced in the ICU.

Increased rates of intensive care unit admission in patients with Mycoplasma pneumoniae: a retrospective study

Mycoplasma pneumoniae is a leading cause of respiratory disease. In the Intensive Care Unit (ICU) setting M. pneumoniae is not considered a common pathogen. In 2010-13 an epidemic of M. pneumoniae-associated infections was reported and we observed an increase of M. pneumoniae patients admitted to ICU. We analysed the cohort of all M. pneumoniae-positive patients' admissions during 2007 to 2012 at the Hadassah-Hebrew University Medical Centre (a 1100-bed tertiary medical centre). Mycoplasma pneumoniae diagnosis was made routinely using PCR on throat swabs and other respiratory samples. Clinical parameters were retrospectively extracted. We identified 416 M. pneumoniae-infected patients; of which 68 (16.3%) were admitted to ICU. Of these, 48% (173/416) were paediatric patients with ICU admission rate of 4.6% (8/173). In the 19- to 65-year age group ICU admission rate rose to 18% (32/171), and to 38.8% (28/72) for patients older than 65 years. The mean APACHE II score on ICU admission was 20, with a median ICU stay of 7 days, and median hospital stay of 11.5 days. Of the ICU-admitted patients, 54.4% (37/68) were mechanically ventilated upon ICU admission. In 38.2% (26/68), additional pathogens were identified mostly later as secondary pathogens. A concomitant cardiac manifestation occurred in up to 36.8% (25/68) of patients. The in-hospital mortality was 29.4% (20/68) and correlated with APACHE II score. Contrary to previous reports, a substantial proportion (16.3%) of our M. pneumoniae-infected patients required ICU admission, especially in the adult population, with significant morbidity and mortality.

Increased Vitamin B12 levels are associated with mortality in critically ill medical patients

BACKGROUND & AIMS

We describe an observational study in critically ill medical patients showing the association between serum Vitamin B12 levels measured on or near admission and the outcome in these patients.

METHODS

We used the database of patients admitted to the Medical Intensive Care Unit (MICU) at the Hadassah-Hebrew University Medical Center in Jerusalem, Israel, to analyze associations between patient demographics, background, diagnoses and serum Vitamin B12 levels with hospital and 90 day outcomes.

RESULTS

Higher mean Vitamin B12 levels were found in patients who did not survive their hospital stay (1719 pg/ml vs 1003 pg/ml, p < 0.01). Those who had died by 90 days after admission to the MICU also had higher Vitamin B12 levels than survivors (1593 pg/ml vs 990 pg/ml). Regression analysis showed that elevated Vitamin B12 levels were associated with increased 90 day mortality, even after controlling for other variables. Survival analysis also showed an increased mortality rate in patients with Vitamin B12 levels over 900 pg/ml (p < 0.0002).

CONCLUSIONS

Our data show that high serum Vitamin B12 levels are associated with increased mortality in critically ill medical patients. We suggest that Vitamin B12 levels should be included in the work-up of all medical intensive care patients, particularly those with a chronic health history and increased severity of illness.

The new College of Intensive Care Medicine--update

Following a lengthy period of development of the training program in intensive care medicine in Australia and New Zealand and the strong support of the Fellowship, the time is right to establish a fully independent College of Intensive Care Medicine. This body will take over the functions of the current Joint Faculty of Intensive Care Medicine from 1 January 2010. Progress reports and news from the College will be posted on the College website: www.cicm.org.au

Non-invasive Mechanical Ventilation Enhances Patient Autonomy in Decision-Making Regarding Chronic Ventilation

OBJECTIVE

Patients with respiratory failure due to progressive muscle weakness often require chronic ventilatory support, but many do not make decisions regarding ventilation prior to a crisis. We studied the use of non-invasive ventilation as a tool to enable communication and facilitate decision-making regarding chronic ventilation.

METHODS

Patients with profound muscle weakness and acute respiratory failure, were supported or weaned by non-invasive positive or negative pressure ventilation. The patients were then interviewed and their informed autonomous decisions were used to plan their future management.

RESULTS

Non-invasive ventilation could be used safely to support patients with acute respiratory failure until decisions regarding chronic ventilation are made and as an alternative means of ventilation for those who refuse tracheostomy.

CONCLUSIONS

Non-invasive ventilation may be used in patients with profound muscle weakness, as a means of enhancing patient autonomy by improving communication and maintaining ventilation until decisions about ongoing care are made.

Clinical evaluation of USCOM ultrasonic cardiac output monitor in cardiac surgical patients in intensive care unit

BACKGROUND

The USCOM ultrasonic cardiac output monitor (USCOM Pty Ltd, Coffs Harbour, NSW, Australia) is a non-invasive device that determines cardiac output by continuous-wave Doppler ultrasound. The aim of this study was to evaluate the accuracy of the USCOM device compared with the thermodilution technique in intensive care patients who had just undergone cardiac surgery.

METHODS

We conducted a prospective study in the 18-bed intensive care unit of a 600-bed tertiary referral hospital. Twenty-four mechanically ventilated patients were studied immediately following cardiac surgery. We evaluated the USCOM monitor by comparing its output with paired measurements obtained by the standard thermodilution technique using a pulmonary artery catheter.

RESULTS

Forty paired measurements were obtained in 22 patients. We were unable to obtain an acceptable signal in the remaining two patients. Comparison of the two techniques showed a bias of 0.18 and limits of agreement of -1.43 to 1.78. The agreement may not be as good between techniques at higher cardiac output values.

CONCLUSIONS

The USCOM monitor has a place in intensive care monitoring. It is accurate, rapid, safe, well-tolerated, non-invasive and cost-effective. The learning curve for skill acquisition is very short. However, during the learning phase the USCOM monitor measurements are rather 'operator dependent'. Its suitability for use in high and low cardiac output states requires further validation.

Air embolism--a case series and review

Venous or arterial air embolism may be a life threatening event. The condition is seen in many fields of medicine, including intensive care. We present a series of three cases of air embolism encountered in the intensive care unit, which demonstrate different pathophysiologies for air embolism in critically ill patients. We also review the literature with respect to aetiology, incidence, pathophysiology, diagnosis and treatment options for venous and arterial embolism.

Percutaneous tracheostomy--long-term outlook, a review

OBJECTIVE

To review the techniques and long term complications of the various techniques of percutaneous tracheostomy in the critically ill patient.

DATA SOURCES

A review of studies reported on the various percutaneous tracheostomy techniques.

SUMMARY OF REVIEW

A tracheostomy is frequently performed in the critically ill patient when prolonged mechanical ventilation, airway protection and pulmonary toilet are required. It is also facilitates weaning from mechanical ventilation, reduces laryngeal injury and improves patient comfort thus decreasing the need for sedation. The percutaneous dilatational technique can be easily and rapidly performed at the bedside. Short-term complication rates associated with percutaneous tracheostomies range between 7-22% and include bleeding, pneumothorax, subcutaneous emphysema, paratracheal insertion, posterior tracheal wall laceration, damage to or insertion through the endotracheal tube, hypoxia, hypotension and arrhythmias, cuff leak, endotracheal tube obstruction, loss of airway, premature extubation and wound infection. Peri-operative mortality ranges from 0.2 to 0.7%. The incidence of these complications often depends on the experience of the operator. Long-term complications and their incidence are not as well defined.

CONCLUSIONS

In the critically ill patient who requires a tracheostomy, the percutaneous tracheostomy has become the method of choice as it can be performed at the bedside, leaves a smaller scar after decannulation and may be associated with fewer complications compared with the standard surgical technique.

Clinical evaluation of the HemoSonic monitor in cardiac surgical patients in the ICU

The HemoSonic monitor (HemoSonic 100, Arrow International, Reading, PA, U.S.A.) is a minimally invasive device to determine cardiac output by means of M-mode and pulsed Doppler ultrasound. We evaluated the HemoSonic monitor by comparing its output to paired measurements obtained by the standard thermodilution technique in patients who had recently undergone cardiac surgery. Forty-seven paired measurements were carried out in 13 patients. The correlation between the two methods was very good with a correlation coefficient of 0.81. Comparison of the two techniques using the method described by Bland and Altman showed a mean of the differences of -0.23. The limits of agreement were -2.35 to 1.89. There was a reduced correlation between techniques at higher values of cardiac output. We concluded that the HemoSonic monitor has a place in intensive care monitoring, with good correlation with cardiac output measured by the thermodilution technique. It appears to be less suitable for use in patients with a high cardiac output state. The oesophageal probe is moderately difficult for patients to tolerate and is only appropriate for use in sedated patients. The accuracy of the device is somewhat operator-dependent.

Long-term outcomes following percutaneous tracheostomy using the Griggs technique

Percutaneous tracheostomy is commonly performed in the intensive care unit. This study assesses the long-term outcomes following percutaneous tracheostomy using the Griggs technique. We carried out a prospective observational cohort study. Two hundred and eight patients who had undergone percutaneous tracheostomy between 1 September 1996 and 31 July 2000 and who were alive at least six months following the procedure, were included in the study. Median follow-up was at 30 months. All patients were sent questionnaires regarding relevant symptoms. One hundred and six (51%) responded and were invited for further follow-up. Forty-three (20.6%) patients underwent scar evaluation by the investigators and 41/208 (19.7%) underwent spirometry. Of the responders, 38% complained of some degree of voice change and 12% complained of ongoing severe cough. Thirty-one per cent complained of shortness of breath, with more than half of these having concomitant heart or lung disease, which may explain this. Eighty-one per cent of patients had minimally visible or a visible but neat scar. Eight patients (8/41 (19.5%)) had some evidence of upper airway obstruction on spirometry, but only 2/41 (5% of patients) were symptomatic (stridor or shortness of breath). We conclude that percutaneous tracheostomy using the Griggs technique has an acceptable long-term complication rate.

The effects of inhalation of a novel nitric oxide donor, DETA/NO, in a patient with severe hypoxaemia due to acute respiratory distress syndrome

Aerosolized NONOates have been investigated in animal models in acute pulmonary hypertension, but none have been used in humans. We report the first use of aerosolized diethylenetriamine nitric oxide adduct (DETA/NO), a NONOate, in a patient with severe acute respiratory distress syndrome. Both pulmonary vascular resistance index and mean pulmonary arterial pressure were reduced by a mean of 26% and 18% respectively after the administration of a single dose of DETA/NO (150 micromol). Intrapulmonary shunting also improved. There were no significant changes in systemic arterial pressure or arterial methaemoglobin concentration after DETA/NO inhalation. We conclude that DETA/NO aerosol produced selective pulmonary vasodilation, with an improvement in pulmonary haemodynamics and oxygenation, while having no measurable effect on the systemic circulation.

Closed-loop control of blood glucose levels in critically ill patients

A closed-loop control system was constructed for automatic intravenous infusion of insulin to control blood sugar levels (BSL) in critically ill patients. We describe the development of the system. A total of nine subjects were recruited to clinically test the control system. In the patients who underwent closed-loop control of BSL, the controller managed to control only one patient's glycaemia without any manual intervention. The average BSL attained during closed-loop control approached the target range of 6-10 mmol/l, and had less deviation than when BSL had been maintained manually. We conclude that closed-loop BSL control using a sliding scale algorithm is feasible. The main deficiency in the current system is unreliability of the subcutaneous glucose sensor when used in this setting. This deficiency mandates high vigilance during use of the system as it is being developed.

Elective awake intubation in a patient with massive multinodular goitre presenting for radioiodine treatment

We present the management of the potential airway complications in a case of massive multinodular goitre treated with radioactive iodine. The patient's trachea was prophylactically intubated, using a fibreoptic technique, to prevent further airway compromise due to thyroid oedema following radioactive iodine treatment. He remained awake and intubated for five days and was extubated when there was no clinical evidence of thyroid oedema as a consequence of his treatment. This approach avoided the considerable risk of thyroidectomy in a morbidly obese patient with airway obstruction. To the authors' knowledge this approach has not been previously described.

Adult-to-adult living donor liver transplantation for fulminant hepatic failure

The outcome of fulminant hepatic failure without timely liver transplantation is poor. We describe a 19-year-old woman with fulminant hepatic failure due to acute hepatitis B infection who received a living donor liver transplant from her sister. The donor's recovery was uneventful, allowing hospital discharge on Day 6. Two months after transplantation the recipient developed a biliary stricture requiring surgery. One year after transplantation, her liver function was normal.

Clinical evaluation of the non-invasive cardiac output (NICO) monitor in the intensive care unit

The Non-invasive Cardiac Output (NICO) monitor (Novametrix Medical Systems Inc., Wallingford, CT, U.S.A.) utilizes a minimally-invasive partial rebreathing method to determine cardiac output by means of a differential form of the Fick equation. We evaluated the NICO monitor by comparing its output to paired measurements obtained by the standard thermodilution (TD) technique in patients who had recently undergone cardiac surgery. Forty-two paired measurements were carried out in 12 patients. The correlation between the two methods was moderate with a correlation coefficient of 0.691. Repeated measures ANOVA showed that TD measures of cardiac output were significantly higher than those obtained by the NICO monitor (P = 0.0003). Comparison of the two techniques using the method described by Bland and Altman showed decreased correlation at higher values of cardiac output. We conclude that the NICO monitor may well have a place in intensive care monitoring, provided patients are not breathing spontaneously and are able to tolerate a 4 mmHg rise in PaCO2. It is less suitable for use in patients with a high cardiac output state.

Pulmonary toxicity of inhaled aerosolized prostacyclin therapy--an observational study

Large white/landrace piglets (mass 11 to 21 kg) were exposed to aerosolized alkaline glycine diluent (n = 2) or inhaled aerosolized prostacyclin (n = 2) for five to eight hours. Pigs receiving these aerosols developed mild acute sterile tracheitis, involving the superficial layers of the trachea, shown histologically and ultrastructurally. Pigs receiving the diluent aerosol also showed mild inflammatory changes in the bronchioles. These findings suggest caution with the use of high volumes of aerosolized alkaline glycine diluent during inhaled aerosolized prostacyclin therapy.

The use of end-tidal carbon dioxide monitoring to confirm intratracheal cannula placement prior to percutaneous dilatational tracheostomy

We tested the utility of intratracheal carbon dioxide monitoring (IT-CO2) in 10 patients undergoing percutaneous dilatational tracheostomy (PDT). We have found IT-CO2 monitoring reliable in confirming the correct position of the tracheal cannula prior to tracheal dilatation using the Portex technique.

Dose-response to inhaled aerosolized prostacyclin for hypoxemia due to ARDS

STUDY OBJECTIVES

This study was carried out to determine the efficacy of and dose-response relationships to inhaled aerosolized prostacyclin (IAP), when used as a selective pulmonary vasodilator (SPV) in patients with severe hypoxemia due to ARDS.

DESIGN

Unblinded, interventional, prospective clinical study.

SETTING

A general ICU in a university-affiliated, tertiary referral center.

PATIENTS

Nine adult patients with severe ARDS (lung injury score, > or = 2.5).

INTERVENTIONS

All patients received IAP over the dose range 0 to 50 ng/kg/min. The IAP was delivered via a jet nebulizer placed in the ventilator circuit. Dose increments were 10 ng/kg/min every 30 min.

MEASUREMENTS AND RESULTS

Cardiovascular parameters (cardiac index and mean pulmonary and systemic pressures), indexes of oxygenation (PaO(2)/fraction of inspired oxygen [FIO(2)] ratio and alveolar-arterial oxygen partial pressure difference [P(A-a)O(2)]) and shunt fraction were measured or calculated at each dose interval, as were platelet aggregation and systemic levels of prostacyclin metabolite (6-keto prostaglandin F1(alpha)). A generalized linear regression model was used to determine a dose effect of IAP on these parameters. The Wilcoxon rank sum test for related measures was used to compare the effects of various doses of IAP. IAP acted as an SPV, with a statistically significant dose-related improvement in PaO(2)/FIO(2) ratio (p = 0.003) and P(A-a)O(2) (p = 0.01). Systemic prostacyclin metabolite levels increased significantly in response to delivered IAP (p = 0.001). There was no significant dose effect on systemic or pulmonary arterial pressures, or on platelet function, as determined by platelet aggregation in response to challenge with adenosine diphosphate.

CONCLUSIONS

IAP is an efficacious SPV, with marked dose-related improvement in oxygenation and with no demonstrable effect on systemic arterial pressures over the dose range 0 to 50 ng/kg/min. Despite significant systemic levels of prostacyclin metabolite, there was no demonstrable platelet function defect.

Extracorporeal circulatory support in near-fatal flecainide overdose

Flecainide, a class 1c antiarrhythmic, has a high mortality associated with significant overdose. We report the case of a 20-year-old female who took approximately 4 grams of flecainide and a small amount of paracetamol as an impulsive gesture. Circulatory failure unresponsive to pacing, inotropes and sodium bicarbonate was successfully treated with cardiopulmonary bypass (CPB). Resolution of her myocardial failure occurred over 24 hours and she was weaned from CPB 30 hours after its initiation. Coagulopathy and intravascular haemolysis were apparent during bypass and necessitated substantial use of blood products. Ischaemic renal dysfunction manifested early in her admission and required haemodiafiltration. Despite a prolonged period of unresponsiveness and pupillary dilatation during resuscitation and CPB she made a full recovery. We believe this is the first reported case of flecainide overdose, requiring extracorporeal circulatory support, not resulting in neurological deficit.

Late outcome from percutaneous tracheostomy using the Portex kit

OBJECTIVE

To assess late outcome following percutaneous tracheostomy using the Portex kit (Hythe, Kent, UK).

DESIGN

Prospective observational cohort study.

SETTING

Teaching hospital.

PATIENTS

Forty-nine consecutive patients who underwent percutaneous tracheostomy in the ICU using the Portex kit and who survived 6 months after the procedure.

INTERVENTIONS

Questionnaires regarding six symptoms were sent to all 49 surviving patients; the 39 respondents were invited to attend for review. Thirteen patients underwent pulmonary function testing, of whom 10 also underwent fiberoptic laryngotracheoscopy under local anesthesia.

RESULTS

The most common symptom was a minor change in voice. One patient had required treatment for symptomatic tracheal stenosis by the time of review; one was referred for revision of a tethered scar. Pulmonary function testing was easily performed by all patients and revealed no evidence of upper airway obstruction. Tracheoscopy likewise showed no evidence of tracheal stenosis.

CONCLUSIONS

One of 49 patients had developed tracheal stenosis. None of the patients attending for detailed review showed any sign of late complications other than one tethered scar.

Validation of Tu's cardiac surgical risk prediction index in a Western Australian population

Tu's cardiac surgical risk prediction index for a Western Australian population was examined in a prospective observational cohort study. Risk score and outcome data were collected for 367 consecutive patients. Logistic regression analysis for Tu score prediction of hospital mortality and linear regression analysis for prediction of ICU and hospital stays were performed. The Tu index accurately predicted mortality rates (P = 0.002, odds ratio 1.46). The linear regression analyses of Tu score on ICU and hospital stays showed an excellent fit (P = 0.0001). The area under the receiver-operating characteristic curve for prolonged ICU stay was 0.75. The Tu risk index is valid for a Western Australian cardiac surgical population and practice.

Contamination of propofol infusions in the intensive care unit: incidence and clinical significance

Epidemics of bacteraemia and wound infection have been associated with the infusion of bacterially contaminated propofol administered during anaesthesia. We conducted an observational study to determine the incidence and clinical significance of administration of potentially contaminated propofol to patients in an ICU setting. One hundred patients received a total of 302 infusions of propofol. Eighteen episodes of possible contamination of propofol syringes were identified, but in all cases contamination was by a low-grade virulence pathogen. There were no episodes of clinical infection or colonization which could be attributed to the administration of contaminated propofol. During the routine use of propofol to provide sedation in ICU patients the risk of nosocomial infection secondary to contamination of propofol is extremely low.

Pharmacokinetics of drugs used in critically ill adults

Critically ill patients exhibit a range of organ dysfunctions and often require treatment with a variety of drugs including sedatives, analgesics, neuromuscular blockers, antimicrobials, inotropes and gastric acid suppressants. Understanding how organ dysfunction can alter the pharmacokinetics of drugs is a vital aspect of therapy in this patient group. Many drugs will need to be given intravenously because of gastrointestinal failure. For those occasions on which the oral route is possible, bioavailability may be altered by hypomotility, changes in gastrointestinal pH and enteral feeding. Hepatic and renal dysfunction are the primary determinants of drug clearance, and hence of steady-state drug concentrations, and of efficacy and toxicity in the individual patient. Oxidative metabolism is the main clearance mechanism for many drugs and there is increasing recognition of the importance of decreased activity of the hepatic cytochrome P450 system in critically ill patients. Renal failure is equally important with both filtration and secretion clearance mechanisms being required for the removal of parent drugs and their active metabolites. Changes in the steady-state volume of distribution are often secondary to renal failure and may lower the effective drug concentrations in the body. Failure of the central nervous system, muscle, the endothelial system and endocrine system may also affect the pharmacokinetics of specific drugs. Time-dependency of alterations in pharmacokinetic parameters is well documented for some drugs. Understanding the underlying pathophysiology in the critically ill and applying pharmacokinetic principles in selection of drug and dose regimen is, therefore, crucial to optimising the pharmacodynamic response and outcome.

Systemic levels of 6-keto-prostaglandin F1 alpha following administration of inhaled aerosolized prostacyclin

A case is described where systemic levels of prostacyclin metabolite were measured during inhaled aerosolized prostacyclin (IAP) therapy for severe hypoxaemia in a patient with the acute respiratory distress syndrome. Comparable levels of prostacyclin metabolite have been associated with a marked platelet aggregation defect in vitro. A platelet aggregation defect was also demonstrated in vivo in this patient. Haemodynamic and gas exchange data during the IAP therapy are described.

Infection in central lines: antiseptic-impregnated vs standard non-impregnated catheters

We report a survey of 196 consecutive central venous catheters (CVCs) placed in 151 patients in the Intensive Care Unit (ICU) over a ten-month period. Over this time the use of a new antiseptic-impregnated triple lumen CVC (Arrowgard Blue, Arrow International Inc., Pennsylvania, U.S.A.) was alternated on a bimonthly basis with the standard triple-lumen CVC (Arrow International Inc., Pennsylvania, U.S.A.). The overall rate of CVC tip infection was lower in the impregnated CVC group (15.6% vs 30.9%, P < 0.05). The impregnated CVC group had a much lower cumulative infection rate when the dwell time in patients was five days or less (3.3% vs 26.9%, P < 0.05). However, the difference between the cumulative infection rate was not statistically significant (P > 0.05) for dwell times of 6, 7 or 8 days respectively. There was no difference in the CVC related bacteraemia rates between the two groups (3.9% vs 3.7%, P > 0.05).

Effect of low concentrations of prostacyclin on platelet function in vitro

The study was performed to determine the possible direct effects of low concentrations of prostacyclin that might spill over into the systemic circulation during the administration of inhaled aerosolized prostacyclin. Platelet aggregation in response to adenosine diphosphate and collagen, as well as measurement of the maximum amplitude of the thrombelastograph (TEG), was undertaken in vitro using venous blood exposed to low concentrations of prostacyclin (0, 10, 100 and 500 pg/ml) from eight healthy volunteers. There were statistically significant reductions in parameters of platelet aggregation in response to the agonists adenosine diphosphate (1 mumol/l and 8 mumol/l) and collagen (10 mumol/l) following exposure to as little as 10 pg/ml of prostacyclin. The maximum amplitude of the TEG was unchanged over the entire range of prostacyclin concentrations studied. The results indicate that low concentrations of prostacyclin or prostacyclin metabolite such as may be observed during inhaled aerosolized prostacyclin therapy are likely to be associated with a marked platelet aggregation defect. This defect was not detected by the TEG.

Central venous catheters revisited--infection rates and an assessment of the new Fibrin Analysing System brush

Sixty-one consecutive patients in the Intensive Care Unit requiring central venous lines (CVC) for five or more days were randomized to receive either a standard triple lumen CVC (STD/CVC) or a silver sulphadiazine and chlorhexidine impregnated CVC (SSD/CVC). Data from the 54 patients who completed the trial show a reduced infection rate (positive tip culture) in the SSD/CVC group (4 out of 28) compared to the STD/CVC group (10 out of 26) (P < 0.05). In addition, the new Fibrin Analysing System (FAS) brush was evaluated and used to determine the presence of infection in all the CVCs (STD/CVC and SSD/CVC combined, n = 54) at day 3 (i.e. early warning of CVC colonization/infection) and at the time of removal of the CVC. The FAS brush was able to detect an infected CVC on only one occasion on day 3 out of the 14 CVC tips which were later found to be colonized/infected at the time of removal. The sensitivity of the FAS brush in detecting colonized/infected CVCs at the time of CVC removal compared with CVC tip culture was 21% with a specificity of 100%. These findings would currently not support the routine use of the FAS brush in determining CVC infection/colonization.

The use of inhaled aerosolized prostacyclin (IAP) in the treatment of pulmonary hypertension secondary to pulmonary embolism

OBJECTIVE

To describe the use of inhaled aerosolized prostacyclin (IAP) in a patient with life-threatening pulmonary hypertension secondary to pulmonary embolism and to discuss the possible use of inhaled prostacyclin in the management of pulmonary embolism.

DESIGN

Case report.

SETTING

Intensive care unit of a university teaching hospital.

PATIENTS

One patient with severe pulmonary hypertension secondary to acute-on-chronic pulmonary embolism.

INTERVENTIONS

Conventional medical management of massive pulmonary embolism and inhaled aerosolized prostacyclin (IAP).

MEASUREMENTS AND RESULTS

Description of clinical course, haemodynamic data and gas exchange data.

CONCLUSIONS

We describe a patient with massive pulmonary embolism for whom the addition of IAP to his therapy appeared to result in a transient improvement in pulmonary haemodynamics and gas exchange.

Bronchoscopic insufflation of room air for the treatment of lobar atelectasis in mechanically ventilated patients

Segmental and lobar pulmonary atelectasis is a common occurrence in mechanically ventilated patients. Standard therapy for atelectasis relies on positive pressure ventilation, positive and 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.

Death by tanning--a case of fatal basic chromium sulphate poisoning

A woman ingested 400 ml of leather tanning solution containing 48 g of basic chromium sulphate (CrOHSO4). This substance forms hydrogen ions and trivalent chromium when it reacts with tissue proteins. The patient died of cardiogenic shock, complicated by pancreatitis and gut mucosal necrosis and haemorrhage. There are no reported cases of toxicity due to oral ingestion of trivalent chromium. Toxicity of hexavalent and trivalent chromium is discussed and suggestions made for management of future cases.

Rapid inhalational induction of anaesthesia with isoflurane or halothane in humidified oxygen

This study was designed to determine the relative speeds of induction and complication rates using either halothane or isoflurane for rapid inhalational induction of anaesthesia. Forty ASA physical status 1 and 2, unpremedicated patients presenting for day-care dental surgery received a rapid inhalational induction (RII) with either halothane 3.5% or isoflurane 5% in humidified oxygen. The carrier gas was humidified in order to limit airway irritation caused by the pungency of the volatile agents. Isoflurane produced a faster induction than halothane-121(50) (SD) sec vs 176(36) sec (P less than 0.01). Complication rates during induction (coughing, secretions, excessive movement and abandoned inductions) were similar for the two groups. The majority of patients in both the isoflurane group (17/20) and the halothane group (14/20) found the technique of RII to be acceptable. The incidences of headache, nausea and vomiting were low and not significantly different for the two groups. Isoflurane 5% in humidified oxygen is as acceptable for RII as halothane 3.5% and has a similar complication rate. Isoflurane may be used for RII in cases where it is deemed necessary to avoid halothane, or when a more rapid inhalational induction is required than is possible with halothane. The technique of RII with either agent in unpremedicated patients is well suited to day-care anesthesia.