[What is the future of palliative medicine in Germany?]

Traditional medical treatment approaches for incurably and terminally ill persons are often felt by the patients and their families to be lacking, since distressing physical and spiritual symptoms of the disease cannot be adequately addressed. In many cases, care in the final stage of life represents a complex medical challenge whose objective is to maintain an individually sufficient quality of life for the patient. New strategies for therapy and care evolving out of the international hospice movement have entered medical training programs under the heading of palliative medicine. Although palliative medicine has only recently enjoyed increasing acceptance in professional as well as lay circles in Germany, it is widespread in many Anglo-Saxon countries, where it also is offered as an academic discipline in research and teaching. According to the most recent American legal interpretations, palliative treatment has been approved as a constitutional right for patients with severely debilitating symptoms. Against the background of sweeping social restructuring, demographic and tumor-epidemiological developments are exerting increasing pressure on our modern societies to improve treatment approaches for incurable patients. In the public itself a changed and more open treatment of the topics of death and dying is becoming apparent, resulting in a demand as well for medical treatment options. From all this, as well as the fact that Germany has been strongly hesitant to establish palliative medicine facilities, it is apparent that there is a clear need to catch up in the area of palliative medicine treatment, research and teaching. The current mood of fiscal restraint in health care may delay medical progress, but it will not be able to prevent it.

[Pain therapy in tumor patients and in palliative medicine. 2: Invasive measures]

Anesthesiological and neurosurgical methods in the treatment of cancer pain have to be considered as parts of a holistic approach. To treat cancer pain patients appropriately, an interdisciplinary setting is essential. In the eyes of experienced pain specialists as well as physicians in palliative medicine invasive procedures are only of minor importance. Their use has been steadily decreasing while neuromodulatory (e.g. intraspinal opioids) or stimulatory (e.g. TENS, DBS, SCS) methods gained wider acceptance. The only neurolytic procedure which still has some importance is the neurolysis of the celiac ganglion for alleviation of pain in the upper abdomen mostly due to pancreatic cancer. This approach seems to be highly effective and tends to be afflicted with only minor complications. Other neurolytic blocks have shown solely local and temporal efficacy. In their majority they are unprecise and often accompanied by severe complications. Therefore these procedures should be scheduled only after carefully weighing risk versus benefit. Where suitable, the use of neurolytics is replaced by radiofrequency thermocoagulation, to a lesser degree by cryoanalgesia. Both procedures normally do not yield better analgesia but do result in fewer complications. Physicians tend to treat pain as a completely somatic disorder, but chronic pain states are always bio-psycho-social in nature. In order to achieve an effective pain treatment all influencing variables have to be taken into account. Anesthesiological and neurosurgical procedures are only a part of the possible and necessary treatment options. Especially before using one of the invasive methods described here, it seems imperative to involve the patient in the process of decision making more closely than currently practiced.

[Ethical challenges in preclinical emergency medicine]

Out-of-hospital emergency medicine, just like any other medical field, must be guided by general ethical principles of medical action. These include respecting the patient's autonomous decision, acting for his benefit, avoiding harm, and justice in distributing the available means. The confrontation with ethical conflicts in the routine of emergency medicine is illustrated by a case report. The emergency physician, called to a 76-year-old patient with circulatory arrest, decides against starting a resuscitation attempt. His decision is based on the fact that at least 15 minutes had passed from the cardiac arrest till the arrival of the emergency care team, on the previously existing, severe cardiac disease, on the age of the patient, on family statements of patient's refusal of resuscitation and on the clinical findings of fixed, dilated pupils, missing brainstem reflexes, and an asystole as an initially recorded cardiac rhythm. No certain clinical signs of death could be observed. In the face of this combination of conditions unfavourable for a successful resuscitation attempt and a survival of the patient, the emergency physician assumes an obvious futility of medical action. The individual criteria are analysed with respect to their prognostic value for estimating the chances of surviving out-of-hospital circulatory arrest. In the context of resuscitation attempts, the term futility can, on the one hand, be defined strictly physiologically, in the sense of the clear impossibility of restoring the cardiac pumping function. The extended definition of the futility of resuscitation attempts, on the other hand, includes an estimate of the nature of survival (duration of survival, neurological outcome) after circulatory arrest. The two definitions share the problem of containing an evaluation of the objective of out-of-hospital resuscitation attempts. In emergency medicine the standard of care remains the start of resuscitation attempts. Physiologically defined futility justifies the decision to withhold resuscitative efforts. In a particular case the refusal by the patient as well as an expected bad prognosis which is inconsistent with the patient's interest could support the emergency physician's decision not to initiate resuscitation. Such an individual decision should not only be guided by medical, but also by ethical considerations and be based on general ethical principles.

[Ethics in preclinical emergency medicine--on the topic of medical futility and resuscitation efforts]

In prehospital emergency medicine, physicians are repeatedly faced with the question of when cardiopulmonary resuscitation (CPR) efforts should be withheld or terminated since they are clearly futile. Here, futile means the goal of saving life cannot be achieved. Determining futility involves qualitative und quantitative aspects. Does the possibility of simply restoring circulatory function justify the decision to initiate resuscitation or must the prospect of a prolonged meaningful life exist? The question of futility arises for the entire life-saving team during resuscitation efforts, for example, after traumatic cardiopulmonary arrest, prolonged down time, collapses in chronically-sick nursing home residents or during transport to hospital when prehospital CPR failed to restore spontaneous circulation. Possible solutions to this problem lie in restricting the objective of resuscitation to achieving a physiological effect in an organ system, i.e. regaining the cardiac pumping function, and in taking into account the chance of long-term survival and quality of life of the patient. Basically speaking, general ethical principles must be adhered to and these include consideration of a patient's right to self-determination. In the prehospital setting, however, the emergency physician is usually confronted with an unknown and unconscious patient and has no information about his preferences. In general, the patient's will to live and his desire for every effort to be made to save him can be assumed, even when there is only a slight chance of survival. Thus, unilateral decisions by emergency physicians to withhold CPR are only justified in special cases when it is obvious that CPR and preservation of life would not be in the patient's interest. When in doubt, resuscitation attempts must be made. The futility of these efforts may emerge later in hospital, or information becomes available regarding the patient's will which justifies an end to therapy.

Ethical aspects of prehospital CPR

Obvious reasons to withhold CPR are signs of death or fatal trauma. If there is any doubt about the appropriateness of CPR, resuscitative measures should be performed. However, CPR should not be attempted like a reflex action, without considering the individual circumstances, the patient's preferences and his prognosis. Age or preexisting diseases are factors that might affect the withholding or withdrawing of CPR, although the decision should not be based solely on these factors, but on criteria with a better predictive value, such as the initial cardiac rhythm and the course of CPR application. Changes in cardiac rhythm might be of prognostic value, because rhythms other than ventricular tachycardia or fibrillation tend to predominate the longer an arrest is in progress. The outcome worsens with prolonged CPR. A termination of unsuccessful CPR after 30 to 45 minutes seems to be reasonable. With respect to the preservation of life as one of the main goals of medicine we have to accept the ethical dilemma that CPR is performed in a number of patients although retrospectively it turns out to have been inappropriate or unwanted by the patient. Nevertheless, therapeutic interventions might be stopped later on after additional information has been obtained. Ethical principles should be taken into account as an action guide when considering the decision to withhold or to terminate resuscitative efforts. However, a detailed and individual ethical analysis in case of conflict is difficult and often impossible in the prehospital emergency situation.

[Causes of failure and dangers in the use of motor driven infusion pumps. Accidental closure of the infusion system]

Syringe drivers are used in anaesthetics, intensive care and emergency medicine to deliver small volumes of highly potent drugs with continuous, constant and reproducible flow. For early recognition of interruptions of the drug delivery caused by occlusion of the infusion system, an alarm is triggered as soon as the system pressure exceeds a certain limit. The sensitivity of this alarm depends on the flow rate, type-specific cut-off pressure and the elastic parameters of the infusion system. The sudden release of pressure built up in the system after occlusion occurred can cause delivery of an uncontrolled drug bolus and hence an additional hazard.

METHODS

Six syringe drivers that are widely used in clinical practice were tested for alarm delay and bolus delivery in the event of an occlusion in the system. First, the alarm pressures at flow rates of 10, 50 and 100 ml/h were measured. Then the alarm delay time and bolus volumes post-occlusion were assessed, using a basic infusion system (syringe + single infusion set). Finally, several alterations to the system like extension, tap battery with germ filters or branching were made and their impact on alarm delay and bolus volume measured.

RESULTS

Because of the great differences in alarm pressures between the devices tested, there were marked differences in the alarm delay at same flow rates. Predictably, there was an indirect proportional link between alarm delay and flow rate. Using the basic infusion system, alarm delays between 23 s and 143 min were measured. In two of the tested syringe drivers, a pressure-release mechanism is activated with the pressure alarm, which prevented bolus application. In the other devices, release of the pressure in the occluded system caused boli of 0.5-7 ml. Variations in the actual syringe volume and insertion of a second connection tube had no impact on alarm delay and bolus volume. Tap batteries, parallel running syringe drivers or trapped air in the system, however, caused marked increase in both alarm delay (107%) and bolus volume (+147%).

DISCUSSION

Unidentified occlusions of the system cause grave malfunctioning of syringe drivers. While applying highly potent drugs, the discontinuation of drug delivery with subsequent bolus application can cause vital danger to the patient. As a result of the significant time delays in the pressure alarms, the devices tested do not provide sufficient protection against unrecognized system occlusion. Syringe drivers with adjustable alarm pressure can be set close to the actual infusion pressure. A further important point is that one should aim at a reduction in the elastic properties of the infusion set because of the great impact on alarm delay and bolus volume.

[Exitus letalis caused by liquid nitrogen]

A 24-year old student died from asphyxiation while filling flasks with liquid nitrogen. The upper and lower extremities and the back were frozen. The face, ears and neck were livid with a horizontal line of demarcation. A few wide ventricular complexes were seen in the initial ECG, followed by asystole. The patient's trachea was intubated, his lungs ventilated with 100% oxygen and CPR initiated. The site of larynx and pharynx were without pathological findings. 250 ml of a crystalloid solution were infused into the external jugular vein. It was not possible to measure the body temperature. Venous blood gas analysis showed a metabolic acidosis and hyperkaliaemia. CPR was terminated after 90 minutes. Own protection is most important for the rescue team if a nitrogen atmosphere is expected.

Pharmacodynamic modelling of the analgesic effects of piritramide in postoperative patients

BACKGROUND

The concentration-effect relationship of piritramide, a synthetic opioid analgesic predominantly used for postoperative analgesia and analgosedation, has not been reported so far.

METHODS

Twenty-four patients of both genders aged 58.1 (11.7) yr (mean (SD)) received inhalational anaesthesia for abdominal surgery. Postoperative pain was assessed with a visual analogue scale (VAS). Analgesia was provided with piritramide, infused at a rate of 7 micrograms.kg-1.min-1 until analgesia was considered sufficient (VAS < 25) or up to a maximum dose of 0.2 mg/kg. The plasma concentrations of piritramide were determined by gas chromatography. An inhibitory fractional sigmoid Emax-model was used to describe the relation between effect site concentration and perceived pain.

RESULTS

The equilibration half-life between plasma and effect site concentrations (T1/2 (keo)) was 16.8 min (median; range: 4.4-41.6 min). The steady-state plasma concentration required to produce 50% of maximum analgesia (EC50) was 12.1 ng/ml (range: 2.9-29.8 ng/ml) and correlated with initial pain intensity. The slope factor gamma was 1.9 (range: 0.5-6.1) and increased with age. Clinically relevant respiratory depression did not occur. Due to the relatively large equilibration half-life of the effect compartment, the context-sensitive half-time of the effect site concentrations after short-time administration (< 2 h) clearly exceeded those of alfentanil, sufentanil, and fentanyl.

CONCLUSIONS

The analgesic effect of piritramide was adequately described by an inhibitory fractional Emax-model. In order to overcome the pronounced hysteresis, piritramide should initially be administered as an intravenous bolus of at least 5 mg.

Skills of lay people in checking the carotid pulse

American Heart Association as well as European Resuscitation Council require the carotid pulse check to determine pulselessness in an unconscious victim and to decide whether or not cardiopulmonary resuscitation (CPR) should be initiated. Recent studies on the ability of health professionals to check the carotid pulse have called this diagnostic tool in question and led to discussions. To contribute to this discussion we performed a study to evaluate skills of lay people in checking the carotid pulse. A group of 449 volunteers (most had participated in a first aid course) were asked to check the carotid pulse in a young healthy, non-obese person by counting aloud the detected pulse rate. Time intervals until correct detection of the carotid pulse were registered. Overall the volunteers needed an average of 9.46 s, ranging from 1 to 70 s. Only 47.4% of the volunteers were able to detect a pulse within 5 s, and 73.7% within 10 s. A level of 95% volunteers detecting the pulse correctly was reached only after 35 s. Based on these findings we conclude that the intervals established for carotid pulse check may be too short and that perhaps the value of pulse check within in the scope of CPR needs to be reconsidered.

[Isokinetic strength of lumbar muscles in patients with chronic backache]

Lumbar isokinetic strength and the influence of age, bodyweight and testing velocity in patients with chronic low back pain in comparison with persons without pain. Lumbar isokinetic strength parameters of 80 patients with chronic low back pain and 70 persons without pain were compared and the influence of age, bodyweight and testing velocity was evaluated. The patients with chronic low back pain showed less strength than the persons without pain. All parameters of extension discriminated between the two groups whereas only some of the flexion parameters did. The isokinetic strength of the lumbal extension muscles was higher than the strength of the flexion muscles. In patients with chronic low back pain, isokinetic strength of lumbar extension muscles was more reduced than the strength of flexion muscles in comparison with persons without pain. At 90 degrees/sec in comparison to 60 degrees/sec, lower extension forces, higher flexion forces and changed ratios of flexion and extension muscles were measured. Age had an influence only on women. There were no changes in ratios of flexion and extension muscles with increasing age. Bodyweight showed weak correlations with isokinetic flexion forces. The influence of different factors on isokinetic force varies between patients with chronic low back patients and healthy subjects.

Prevention of patient bacterial contamination of anaesthesia-circle-systems: a clinical study of the contamination risk and performance of different heat and moisture exchangers with electret filter (HMEF)

The microbiological contamination of 250 breathing system tubes after use in anaesthesia circle systems with reduced fresh gas flow was investigated. The lungs of 50 patients were ventilated without any filtering device between the endotracheal tube and the Y-piece. A total of 51, 49 and 100 patients, respectively, were given different types of heat and moisture exchanger with electret filters (HMEF). With no filtering device the tubing system was contaminated by microorganisms originating from the patient's tracheal secretion in 13% of the patients. In contrast, no bacterial migration into the tubing system was detected when any of the investigated HMEF-devices were used. We therefore conclude that heat and moisture exchangers with electret filters prevent contamination of the anaesthesia breathing system with microorganisms from the patients airways.

[Ethical conflicts in emergency medicine]

OBJECTIVE

Thirty years ago, cardiopulmonary resuscitation (CPR) was primarily developed for otherwise healthy individuals who experienced sudden cardiac arrest. Today, CPR is widely viewed as an emergency procedure that can be attempted on any person who undergoes a cessation of cardiorespiratory function. Therefore, the appropriateness of CPR has been questioned as a matter of the outcome, the patient's preferences, and the cost. The objective of this article is to analyse ethical issues in prehospital resuscitation.

ARGUMENTS

CPR is bound by moral considerations that surround the use of any medical treatment. According to Beauchamp and Childress, the hierarchy of justification in biomedical ethics consists of ethical theories, principles, rules, and particular judgements and actions. The decision to start CPR is based on the medical judgement that a person is suffering from circulatory arrest. The decision is justified by the moral rule that the victim of a cardiac arrest has the right to survive and to receive CPR. Moral rules are more specific to contexts and are based on ethical principles. The principle of beneficence means the provision of benefits for the promotion of welfare. Talking about beneficence in resuscitation means once again reporting stories of success, as many victims of pre- and in-hospital sudden death have been saved in the past. Nevertheless, resuscitative efforts still remain unsuccessful in the majority of cases, involving the principle of nonmaleficence. There is potential harm in CPR. Survivors may recover cardiac function, but sustain severe hypoxic brain damage, at worst surviving without awakening for months or years. In particular, post-traumatic CPR is associated with an extremely poor outcome, leading to the issue of futility. However, futility should be defined in a strict fashion, as there might be an individual chance of survival. The principle of respect for autonomy means the right of a patient to accept or reject medical treatment, which continues in emergency conditions and after the patient has lost consciousness. The time frame in CPR requires medical decision-making within seconds, and CPR is usually initiated without the patient's involvement. If the patient's wish's can be ascertained later on, life-sustaining therapies might be withdrawn at the time. Terminally ill but still competent patients should be encouraged to write a no-CPR document, which does not deny patients relief from severe symptoms, but might facilitate withholding resuscitative efforts at the scene. The principle of justice affects priorities in the allocation of health care resources. The decision made for a particular patient might delay or prevent emergency treatment in other patients who could receive greater benefit.

CONCLUSIONS

The standard of care remains the prompt initiation of CPR. However, ethical principles such as beneficence, nonmaleficence, autonomy, and justice have to be applied in the unique setting of emergency medicine. Physicians have to consider the therapeutic efficacy of CPR, the potential risks, and the patient's preferences.

The decision to terminate resuscitative efforts: results of a questionnaire

Despite all the progress made in emergency medicine, out-of-hospital resuscitative efforts still remain unsuccessful in the majority of cases and a decision concerning termination of cardiopulmonary resuscitation (CPR) has to be made. We used a multi-question survey to assess the attitude of emergency physicians towards the duration of an unsuccessful resuscitation attempt in non-traumatic cardiac arrest, and to identify the criteria affecting the decision to terminate CPR in the prehospital setting. More than 400 physicians participated in the inquiry on CPR in adults. If spontaneous circulation cannot be restored, the majority (65%) abandon the resuscitation attempt at the latest after performing advanced cardiac life support for 45 min. The participants indicated the following factors as criteria for the termination of unsuccessful CPR: pre-existing diseases (92%), presumed interval between onset of arrest and application of CPR (92%), duration of the resuscitation attempt (90%), age of the patient (89%), electrocardiographic (ECG) alterations such as persistent asystole/ventricular fibrillation or electromechanical dissociation (83%), persistent fixed and dilated pupils (78%), lack of brain stem reflexes (31%), body temperature (12%) and suspected drug intoxication (8%). The answers reflect the physicians opinions on termination of CPR even if they do not present real decisions under emergency conditions. The results indicate that in addition to the failure to restore spontaneous circulation, other factors are involved in decision making at the scene. A high rate of respondents include criteria of weak diagnostic value such as the pupillary status, or factors of doubtful prognostic significance such as the patient's age. Concerning the patient's history and underlying diseases, the emergency physician often has to resort to presumptions. We conclude that the decision to terminate CPR is made by most physicians considering the specific circumstances of the cardiac arrest.

Use of modified fluid gelatin and hydroxyethyl starch for colloidal volume replacement in major orthopaedic surgery

We have compared 6% hydroxyethyl starch (HES 200/0.5) with 3% modified fluid gelatin (MFG) for volume replacement in major orthopaedic surgery and studied the effects on haemodynamic state, colloid osmotic pressure, blood clotting and plasma homeostasis. Using a controlled, randomized, single-blind clinical design, we studied 46 consecutive patients undergoing major elective orthopaedic hip surgery. The two groups were comparable in age, body weight and duration of surgery. Patients were maintained haemodynamically stable using both HES and MFG over the entire study. Fluid balance and colloidal replacement volumes were comparable in both groups (median perioperative infusion volume: HES 2500 ml, MFG 2400 ml). Laboratory variables were not clinically different. We conclude that both colloidal solutions were comparable in volume efficacy and effects on plasma oncotic pressure, clotting and plasma homeostasis. In the small number of patients studied, 6% HES 200/0.5 was found to be safe when administered in amounts corresponding to the currently accepted maximum daily dose in Germany and France of 33 ml/kg body weight and 2.0 g/kg body weight, respectively.

ACD versus standard CPR in a prehospital setting

BACKGROUND

Animal and human studies in cardiac arrest demonstrate significant improvements in systolic blood pressure, coronary perfusion pressure and total brain and myocardial blood flow with active compression-decompression (ACD) cardiopulmonary resuscitation (CPR). The results of recent studies in patients with out-of-hospital cardiac arrest and use of ACD-CPR are non-uniform and require supplementation.

METHODS

In a retrospective non-randomised design, 152 adult patients with prehospital cardiac arrest, not caused by trauma or hypothermia, were studied. Compressions were performed according to the recommendations of the American Heart Association. Three ACD devices were assigned to seven rescue units changing monthly. Study end-points were the rates of return of spontaneous circulation (ROSC), admission to hospital, survival at 24h, hospital discharge and neurologic outcome.

RESULTS

70 (46%) patients underwent standard (STD) CPR and 82 (54%) patients were treated with ACD-CPR. Both groups were comparable with regard to age, sex, witnessed cardiac arrests, bystander CPR, cause of arrest, time intervals, number of defibrillations, and total amount of epinephrine. No significant differences in outcome could be found: 20 patients (29%) who received STD-CPR, and 14 patients (17%) who underwent ACD-CPR survived to hospital discharge. Neither at other end-points nor in any subgroups could any significant differences be discovered. Patients regaining ROSC showed a significant difference in favour of STD-CPR for the end-points of hospital admission, 24-h survival and hospital discharge.

CONCLUSION

No significant differences in hospital discharge and neurological outcome were found between STD-CPR and ACD-CPR.

Pharmacokinetics of piritramide after an intravenous bolus in surgical patients

BACKGROUND

Piritramide is a synthetic opioid analgesic which is commonly used for postoperative analgesia. It is structurally related to meperidine, exhibiting full mu-receptor agonism. Pharmacokinetic data of the drug have not been reported so far.

METHODS

Plasma protein binding of piritramide was studied in vitro. The kinetics were examined after a single intravenous bolus (0.2 mg/kg) in 10 male patients aged 22-53 years undergoing elective minor surgery. Plasma and urine concentrations were determined by gas chromatography in samples drawn before and after the bolus. The concentration vs. time data were evaluated by nonlinear regression analysis, and the mean values and SD of the individual pharmacokinetic parameters were calculated. A three-compartment body model was fitted to the data.

RESULTS

The volume of distribution at steady state was 4.7 (0.7)l/kg, systemic plasma clearance was 7.8 (1.5) (mean (SD)) ml/kg/min. Renal clearance of unchanged piritramide was negligible (0.13 (0.09) ml/kg/min). The terminal elimination half-life was 8.0 (1.4) h. In vitro, the free fraction in plasma of piritramide did not change over the therapeutic concentration range (5.5 (1.3)% at a pH of 7.35) but decreased considerably with pH within the physiological range.

CONCLUSION

Since the elimination half-life of piritramide appears to exceed the duration of clinically effective analgesia observed during the treatment of acute pain, the dose of piritramide should be titrated carefully during long-term treatment to avoid accumulation that may lead to adverse effects.

[Is reduction of intraoperative heat loss and management of hypothermic patients with anesthetic gas climate control advisable? Heat and humidity exchangers vs. active humidifiers ina functional lung model]

Heated humidifiers (HH) as well as heat and moisture exchangers (HME) are commonly used in intubated patients as air-conditioning devices to raise the moisture content of the air, thus preventing mucosal damage and heat loss resulting from ventilation with dry inspired gases. In contrary to HME, HH are able to add heat and moisture to the inspired air in surplus, which is often stressed as an advantage in warming hypothermic patients or reducing major heat losses, e.g., during long operations. The impact of air conditioning on the energy balance of man was calculated comparing HME and HH.

METHODS

The efficiency of a HME (Medisize Hygrovent) and a HH (Fisher & Paykel MR 730) was evaluated in a mechanically ventilated lung model simulating the physiological heat and humidity conditions of the upper airways. The gas flow from the central supply was dry; the model temperature varied between 32 and 40 degrees C. By using a HH in the inspiratory limb, a circle system was simulated with water-saturated inspired air at room temperature. The water content of the ventilated air was determined at the tracheal tube connection using a fast, high-resolution humidity meter and was compared with the moisture return of the HME. The energy balance was calculated according to thermodynamic laws.

RESULTS

Both HME and HH were able to create physiological heat and humidity conditions in the airways. With the normothermic patient model, the moisture return of the HME was equal to that of the HH set at 34 degrees C. Increasing the heating temperature resulted only in reduced water loss from the lung; heat and water input in the normothermic model was not possible. This was only effective with almost negligible amounts under hypothermic patient model conditions.

DISCUSSION

The water content in the inspired and expired air is the most important parameter for estimating pulmonary heat loss in mechanically ventilated patients. In adults (minute volume approximately 71/min) the main fraction of pulmonary heat loss results from water evaporation from the airways (approximately 6 kcal/h), whereas the heat loss due to convection is negligible (approximately 1.2 kcal/h). In intubated patients ventilated with dry air, the heat loss increases to approximately 8 kcal/h due to greater water evaporation from the airways. Both HME and HH are able to reduce the pulmonary heat loss to 1-2 kcal/h. In normothermic as well as hypothermic patients, HH do not offer significant advantages in heat balance compared to effective HME. In conclusion, air conditioning in intubated patients is neither a powerful too for maintaining body temperature during long-lasting anaesthesia nor a sufficient method of warming hypothermic patients in intensive care units.

Influence of different types of recovery positions on perfusion indices of the forearm

BACKGROUND

Basic life support guidelines of the European Resuscitation Council (ERC) suggest a modified type of recovery position compared to that recommended by the American Heart Association (AHA). However, anecdotal reports and the results of a small study by Fulstow and Smith (Resuscitation 1993; 26: 89-91) gave evidence that the new ERC position may cause an impairment of perfusion of the lower forearm. The aim of our study was to evaluate the effects of different recovery positions on arterial perfusion and venous drainage of the forearm.

METHODS

We placed 20 young healthy volunteers randomly in either ERC or AHA position for 15 min first, and in the other position thereafter. Before and between volunteers were positioned supine. In a second series 10 volunteers were positioned according to the same protocol in semiprone positions as described by Morrison, Mirkhur and Craig (MMC), and Rautek's position, respectively. Forearm perfusion indices of the dependent arm were continuously assessed by photoplethysmographic pulsatility change, photoplethysmographic volume change, invasive peripheral venous pressure and non-invasive blood pressure amplitude. Subjective discomfort was assessed non-qualitatively.

RESULTS

All indices of arterial perfusion demonstrated an impairment of arterial inflow in ERC, MMC and Rautek's position as well as venous congestion in these three positions. On the contrary, AHA position was associated with no significant changes of arterial flow and only moderate, insignificant signs of venous congestion.

CONCLUSION

The results of this study suggest that AHA position causes less circulatory disturbances than the ERC, MMC and Rautek's positions.