Prehospital advanced life support provided by specially trained physicians: is there a benefit in terms of life years gained?

BACKGROUND: The benefit of prehospital advanced life support (ALS) is disputed, as is the prehospital use of specially trained, hospital-based physicians. The purpose of the study was to assess the health benefit from an anesthesiologist-manned prehospital emergency medical service (EMS), and to separate the benefit of the anesthesiologist from that of rapid transport. METHODS: The anesthesiologist-manned helicopter and rapid response car service at Rogaland Central Hospital assisted 1106 patients at the scene during the 18-month study period. Two expert panels assessed patients with a potential health benefit for life years gained (LYG) using a modified Delphi technique. The probability of survival as a result of the studied EMS was multiplied by the life expectancy of each patient. The benefit was attributed either to the anesthesiologist, the rapid transport or a combination of both. RESULTS: The expert panels estimated a benefit of 504 LYG in 74 patients (7% of the total study population), with a median age of 54 years (range 0-88). The cause of the emergency was cardiac diseases (including cardiac arrest) in 61% of the 74 patients, trauma in 19%, and cardio-respiratory failure as a result of other conditions in 20%. The LYG were equally divided between air and ground missions, and the majority (88%) were attributed solely to ALS by the anesthesiologist. CONCLUSION: The expert panels found LYG in every 14th patient assisted by this anesthesiologist-manned prehospital EMS. There was no difference in LYG between the helicopter and the rapid response car missions. The role of the anesthesiologist was crucial for health benefits.

Threats from patients and their effects on medical decision making: a cross-sectional, randomised trial.

BACKGROUND: Negative experiences are not uncommon among doctors in Norway. Our aim was to find out about the various types of negative reactions (eg, complaints, negative exposure to the media, financial claims, and notification to the police) received by physicians from patients or relatives in response to treatment, to identify their cause, and to study their effects on subsequent clinical decisions. METHODS: We posted questionnaires about negative reactions of patients to a random sample (n=1260) of Norwegian doctors. Each doctor was additionally sent five written case simulations and asked to choose one of several proposed clinical strategies. Half (630) the physicians received cases containing threats from the patient or their relatives. FINDINGS: 988 (78%) physicians returned the questionnaire, 463 (47%) of whom reported negative experiences. Such experiences were reported more frequently by men (357 [51%]) and family physicians (157 [58%]) than by other participants. Negative experiences did not affect choice of strategy for case simulations. For the first case, chest pain, 217 (44%) physicians presented with a threat chose a defensive strategy compared with 145 (30%) of those who were not (difference 14%; 95% CI 8-20). For the second case, a headache case, the corresponding numbers were 278 (57%) and 118 (25%) (32%; 26-38). Physician age, sex, specialty, or experience of negative reactions of patients did not alter the effect of threats received during our study. INTERPRETATION: Negative experiences do not affect subsequent decision making. However, doctors do comply with wishes from patients or relatives when presented with direct threats.

Doctor-staffed ambulance helicopters: to what extent can the general practitioner replace the anaesthesiologist?

During two years, a rural ambulance helicopter programme saved 41 patients' lives. In 29 of these patients, the decisive medical interventions were carried out by the flight anaesthesiologist before reaching the hospital. We asked an expert panel to assess whether these interventions could have been carried out by a general practitioner (GP). This was the case for 17 (59%) of the 29 patients, while more advances skills, equipment or drugs were needed for 11 (38%). Among these 11, three patients would probably have died without the interventions. We conclude that GPs can manage a majority of life saving missions for a rural ambulance helicopter programme, but the lack of a flight anaesthesiologist may imply substantial health losses for a few patients.

How urgent are emergency admissions? An evaluation of emergency admissions to general hospitals in a Norwegian county.

OBJECTIVES: To assess necessary treatment and degree of urgency for patients admitted to emergency rooms, and potential health consequences of transfer to nearest alternative hospital. METHODS: During 1 month, we included all 1,300 emergently admitted patients in all seven general hospitals in a Norwegian county with a population of 236,921 inhabitants. The number of patients in need of surgical and/or intensive medical treatment, the urgency of the necessary treatment, and the risk to each patient of adverse permanent health consequences of further transport to nearest alternative hospital were assessed by a multidisciplinary expert panel. RESULTS: Ninety-four patients (7.2% of 1300 patients) were considered in need of either surgical (n = 22) or intensive medical treatment (n = 70) or both (n = 2) within 8 hours of arrival in hospital. Medical treatment had the greatest urgency, while surgery most often could be postponed. In cases where the patients were initially to be given only stabilizing treatment and then transported (assisted by qualified personnel) to another hospital, the panel estimated the risk of losing health benefit to be high for 14 patients. In six of these cases the risk was linked to delay of thrombolytic treatment. CONCLUSIONS: Fewer than 10% of the patients who are admitted as emergency cases to general hospitals in Norway need surgical or intensive medical treatment within 8 hours of their arrival. The medical consequences of transport of patients to the nearest alternative hospital are generally small and can often be further reduced by simple means.

Which groups of patients benefit from helicopter evacuation?

BACKGROUND: The evacuation of emergency cases by air, usually by helicopter, is controversial because of the cost of the programme, the possibility of an accident (especially in an urban area), and unproven benefit. But such evacuations cannot be studied by a random intervention (eg, air versus ground ambulance). We used an expert-panel approach to estimate the health outcome for patients transferred by emergency helicopter compared with the potential outcome if they had gone by surface ambulance. METHODS: The helicopter programme is based at the University Hospital of Tromsø in northern Norway. 370 case-reports of helicopter evacuation from rural areas were screened by anaesthetists for routine and case-specific data. Two expert panels assessed the cases for potential additional health benefit arising from the fact of helicopter evacuation. The panels used a modified Delphi technique to reach consensus in life-years gained. One panel met for cases aged under 15 and pregnant women, the other for older cases. FINDINGS: 240 of the 370 cases were male (65%); the age range for both sexes was 0-86 years. The most common diagnosis for the 55 cases aged under 15 was infection (49%); in older patients, cardiovascular disease dominated (50%). Trauma accounted for just under a fifth of cases in both groups. On average, the patients arrived 69 min (range 0-615) earlier in hospital than if they had gone by ground transport. For 283 cases, the initial screening by the anaesthetists indicated no additional benefit compared with that obtainable by ground-ambulance transport. The main reason was that no treatment was given during the flight or early on in hospital that could not have been given otherwise. 90 cases entered the expert panel system. Of these 90, 49 cases were judged to have received no additional benefit. This left 41 (11% of the total of 370 evacuated) who were judged to have benefited, gaining 290.6 life-years. 96% of the total number of life-years gained was achieved in nine patients, six of whom were aged below 7 (four were aged 0-7 months). The life-year-gain per adult patient with cardiovascular disease was 0.54. INTERPRETATION: We conclude that an emergency helicopter service can provide considerable health benefits for selected patients, at least in this rural setting. Given the costs and risks of such a service, the benefits for most patients are small.

Extracorporeal membrane oxygenation (ECMO) as lung or heart assist.

Extracorporeal membrane oxygenation (ECMO) may serve as extracorporeal lung assist (ECLA) in patients with acute respiratory failure (ARF) or as extracorporeal heart assist (ECHA) in patients with low output syndrome (LOS) after open heart surgery. From 1988 to 1992 seven patients underwent ECMO in our hospital; four suffered from ARF and three from LOS. Various bypass techniques were employed. Two ARF patients, aged 58 and 18 years, had veno-venous bypass; in the latter, ECMO was reinstituted as a veno-arterial bypass one week after weaning. In a three-year-old boy, the ECMO outflow tubing was primarily connected to the pulmonary artery, and shortly afterwards relocated to the common carotid artery. In a 31-year-old man with ARF, and three LOS patients, a 56-year-old woman, and two men aged 68 and 70 years, ECMO was veno-arterial with direct access to the ascending aorta. A heparin-coated system was used, and all but one patient, who was treated with warfarin, received a daily low dose of heparin, which was withdrawn after from one to nine days. Six patients were weaned off ECMO after 4.5 to 21 days. Three ARF patients recovered completely; the child died. In one LOS patient, ECMO was withdrawn due to a poor general condition. Two others were weaned off ECMO and the intra-aortic balloon pump, and the inotropic support was significantly reduced, but both died of multiple system organ failure. Although no firm conclusions can be drawn from these few case reports, the heparin-coated system used as ECLA appears promising, whereas ECHA seems to imply a poor prognosis in patients who are not candidates for cardiac transplantation.

Postinfarction rupture of left ventricular free wall repaired with a glued-on pericardial patch. Case report.

In a 68-year-old man admitted in deep shock, prompt echocardiographic diagnosis of postinfarction left ventricular free wall rupture was followed by probably life-saving pericardiocentesis. At emergency surgery a 2 cm linear tear in the anterolateral wall of the left ventricle was successfully repaired with a glued-on pericardial patch, without infarctectomy or placement of sutures in the infarcted area.

Nitrogen retention caused by growth hormone in patients undergoing gastrointestinal surgery with epidural analgesia and parenteral nutrition.

Nineteen patients undergoing elective gastrointestinal surgery were randomised to receive recombination human growth hormone (n = 9) or placebo (n = 10) for the first five postoperative days. All received epidural analgesia and total parenteral nutrition during the same period (energy supply 125% of basal metabolic rate, mean nitrogen (+/- SEM) 5.7 (+/- 0.1) g/m2). Nitrogen and potassium retention was induced in the growth hormone group compared with the placebo group (cumulative nitrogen balance 4.1 (+/- 1.1) g/m2 in the growth hormone group and -3.1 (+/- 1.8) g/m2 in the placebo group, p less than 0.01; cumulative potassium balance 80.8 (+/- 4.7) mmol/m2 in the growth hormone group and 43.1 (+/- 11.4) mmol/m2 in the placebo group, p less than 0.01). In the growth hormone group, serum glucose concentrations increased each evening and mean serum albumin concentrations were reduced throughout the period; the morning pulse rates were decreased, and the patients gained weight compared with the placebo group.

[Enterobacter cloacae infections at the Regional Hospital in Tromsø]. / Enterobacter cloacae-infeksjoner ved Regionsykehuset i Tromsø.

Enterobacter cloacae was isolated from 69 patients hospitalized at the University Hospital of Tromsø, Norway, during a period of 18 months. The total lethality was 11.6% (8/69) and death occurred most often in patients with a serious underlying condition. Death due to septicaemia occurred in 4/10 patients. Multiple beta-lactam resistant strains were present in 15 patients and were associated with septicaemiae (7/10, p less than 0.0005). Cephalosporin treatment had been given to every third patient (24/69), and nearly half of them (10/24) were infected by multiple beta-lactam resistant E cloacae. E cloacae occurred mainly as a nosocomial infection, since more than 70% of all patients infected had been treated by an invasive procedure prior to isolation of the bacterium. A high number of E cloacae strains were from operation wounds, especially among patients at the Department of Surgery (22/30). At this Department, the total number of E cloacae, and especially the number of multiresistant strains, was markedly reduced during restricted use of cefalosporins.

Immobilization of Norwegian reindeer (Rangifer tarandus tarandus) and Svalbard Reindeer (R. t. platyrhynchus) with medetomidine and medetomidine-ketamine and reversal of immobilization with atipamezole.

The sedative action of medetomidine (-ketamine) was studied in 12 captive Norwegian semidomesticated reindeer (NR), including 4 newborn calves, and in 7 free-living Svalbard reindeer (SR). Medetomidine, with or without ketamine, caused effective, reliable immobilization in NR. Doses of 50-200 micrograms/kg medetomidine alone or 30-125 micrograms/kg medetomidine combined with greater than or equal to 300 micrograms/kg ketamine induced complete immobilization, good muscle relaxation and persistent, deep sedation with little respiratory depression in NR; SR required higher doses. Atipamezole successfully antagonized medetomidine (-ketamine) resulting in rapid and persistent reversal of immobilization in all cases (NR and SR). Both medetomidine and atipamezole had wide safety margins and no conspicuous lasting side effects after reversal.

Multiply beta-lactam resistant Enterobacter cloacae infections linked to the environmental flora in a unit for cardiothoracic and vascular surgery.

During the period March 1987-May 1988, postoperative infection or colonization with Enterobacter cloacae occurred in 9/379 (2.4%) patients who underwent cardiovascular surgery. Five of the patients were infected with multiply beta-lactam resistant E. cloacae, of whom 4 had been infected with an identical, resistant strain during intervals of months. This strain was also found in the environmental flora of the cardiovascular operating suite and in a sink reservoir in the surgery department. All 4 patients with the identical resistant strain had serious complications during the postoperative period with symptoms of septicaemia in 3, multiorgan failure and shock in 2, and mediastinitis in 3. The single resistant strain of a different serotype was also associated with severe postoperative complications. The 4 sensitive strains were all different serotypes. None caused septicaemia, one was associated with mediastinitis, another with an uncomplicated sternum infection, and 2 were from sputum. In the 3 latter patients with sensitive strains and few postoperative complications, cephalosporins had not been used during the pre- or postoperative period.

[Nosocomial infections with resistant Enterobacter cloacae. Effects on the disease and the treatment]. / Nosokomial infeksjon med resistente Enterobacter cloacae. Betydning for sykdomsforløp og behandling.

We describe five patients with serious nosocomial infection caused by resistant Enterobacter cloacae. Four of the patients underwent cardiovascular operations and were infected with an identical, multiple beta-lactam resistant E cloacae strain. The fifth patient was admitted with several wounds and skin-ulcers containing both resistant and sensitive E cloacae of other types. The resistant strain caused septicemia in four patients; three developed multiorgan failure and one died. The most probable causes of these infections were an abundant and constant reservoir of E cloacae in a sink at the operating unit, periodical breakdown of barriere routines, and heavy use of cephalosporins.

Class III antiarrhythmic action linked with positive inotropy: antiarrhythmic, electrophysiological, and hemodynamic effects of the sea-anemone polypeptide ATX II in the dog heart in situ.

Most antiarrhythmic drugs are more or less negatively inotropic. Positively inotropic properties, however, have been demonstrated for some class III antiarrhythmic drugs. To test the hypothesis that class III antiarrhythmic effect and positive inotropy may be linked, we used the sea-anemone polypeptide ATX II, which in isolated heart muscle preparations has been shown to specifically inhibit the inactivation of the sodium channel and thereby increase action potential duration and inotropy. We used 12 pentobarbital-anesthetized dogs. Atrial arrhythmias were induced by high-rate stimulation of the right atrium in 5 dogs. Cardiac electrophysiological effects were studied by His-bundle electrography, programmed electrical stimulation, and monophasic action potential (MAP) recordings in 7 autonomically blocked dogs. ATX II (1.0-5.0 micrograms/kg i.v.) converted the arrhythmias, and in the autonomically blocked dogs markedly increased atrial and ventricular refractoriness and ventricular MAP duration without influencing atrial or ventricular conduction velocities, heart rate, or AV-nodal refractoriness. ATX II induced a marked increase in left ventricular dP/dt max. The study indicates that ATX II has class III antiarrhythmic effect, and that the electrophysiological and positive inotropic effects of ATX II have a common mechanism.

Cardiac effects of thoracic epidural morphine caused by increased vagal activity in the dog.

This study was carried out in order to investigate possible side-effects of thoracic epidural morphine on cardiac electrophysiology, haemodynamics and metabolism. In pentobarbital-anaesthetized dogs, intracardiac conduction times were determined by His bundle electrography, and refractoriness by programmed electrical stimulation; monophasic action potential recordings were obtained from the right ventricle by the suction electrode technique. Cardiac output, left ventricular and aortic blood pressures were measured, as well as plasma concentrations of morphine, free fatty acids, glycerol, glucose and lactate. Thoracic epidural morphine (0.12 mg X kg-1) reduced spontaneous heart rate, prolonged atrioventricular nodal conduction time and refractoriness, and reduced left ventricular dP/dt max. Bilateral vagotomy reversed these effects. Intra-atrial, His Purkinje and intraventricular conduction times, atrial and ventricular refractoriness and action potential duration, stroke volume and mean aortic blood pressure, as well as the metabolic variables, were not significantly influenced by thoracic epidural morphine with or without vagotomy. Peak plasma morphine levels of 12-25 ng X ml-1 were measured 10 min after morphine injection. In conclusion, this study demonstrates depressive side-effects of epidural morphine on cardiac function, mediated by an increased vagal activity.

Central control of expired air temperature and other thermoregulatory effectors in reindeer.

Norwegian reindeer (Rangifer tarandus tarandus) were provided with chronically implanted hypothalamic perfusion thermodes to determine to what extent expired air temperature (Tex) is centrally controlled. The effects that alterations of hypothalamic temperature (Thy) had on metabolic heat production, respiratory frequency, respiratory evaporative heat loss, and rectal and leg-skin temperature were simultaneously recorded. Experiments were conducted in conscious animals exposed to ambient temperatures (Ta) of -20, 0, and 20 degrees C in summer, when fur insulation was minimal, and in winter, when it was prime. Altering Thy induced changes in Tex, the degree and direction of which depended on the prevailing Ta, season, and intensity of hypothalamic thermal stimulation. These results indicate that Tex, and hence nasal heat exchange, is under central control. The Thy-induced changes in the other measured parameters confirm that hypothalamic thermosensitivity in these animals is similar to that previously found in other mammalian species.

Cardiac electrophysiologic and hemodynamic effects related to plasma levels of bupivacaine in the dog.

To investigate electrophysiologic and hemodynamic responses to various plasma levels of bupivacaine, especially those in the range normally seen during regional anesthesia, bupivacaine was given intravenously as a bolus dose followed by continuous infusion in pentobarbital-anesthetized dogs. Cardiac electrophysiology was studied by His bundle electrography, programmed electrical stimulation, and monophasic action potential recordings. At plasma bupivacaine concentrations below 1000 ng/ml, no significant electrophysiologic or hemodynamic effects were observed. This indicates that systemic responses to absorbed bupivacaine do not contribute to the cardiac electrophysiologic effects recently demonstrated during thoracic epidural analgesia. At a plasma level of about 2000 ng/ml, a level occasionally achieved during regional anesthesia, bupivacaine prolonged impulse conduction time in all parts of the heart, prolonged atrial and AV nodal refractoriness, decreased left ventricular inotropy, but had no effect on ventricular refractoriness or monophasic action potential duration. These electrophysiologic effects may enhance susceptibility to reentrant arrhythmias.

Cardiac electrophysiological and hemodynamic effects of beta-adrenoceptor blockade and thoracic epidural analgesia in the dog.

To investigate whether thoracic epidural analgesia (TEA) has additional cardiac electrophysiological and hemodynamic effects when induced after beta-adrenergic blockade, bupivacaine (0.7-1.2 mg/kg) was injected into the epidural space at T2-3 after intravenous injection of atenolol (1.0 mg/kg) in anesthetized dogs. Cardiac electrophysiology was studied by His bundle electrography, programmed electrical stimulation, and monophasic action potential recordings. Atenolol reduced heart rate, prolonged atrio-ventricular (AV) nodal impulse conduction time and refractoriness, prolonged ventricular refractoriness and action potential duration, and decreased left ventricular (LV) dP/dt max. Addition of TEA further reduced heart rate, prolonged AV nodal conduction time and refractoriness, decreased LV dP/dt max and arterial blood pressure, but had no effect on atrial and ventricular electrophysiology. Induction of TEA during beta-blockade may thus have additive depressive effects on sinoatrial and AV nodal functions, as well as on left ventricular inotropy. The study indicates that the cardiac electrophysiological effects induced by TEA are mainly caused by decreased beta-receptor stimulation, but increased vagal activity may also contribute.

Effects of thoracic epidural analgesia on cardiovascular function and plasma concentration of free fatty acids and catecholamines in the dog.

Increased plasma levels of free fatty acids (FFA), leading to increases in the myocardial oxygen demand, are seen after, for example, surgical stress, traumas and myocardial infarction. The present study was undertaken to investigate the cardiovascular effects of thoracic epidural analgesia (TEA) and the effect of TEA on the plasma concentration of FFA and catecholamines. In 10 sodium-pentobarbital-anaesthetized dogs the local anaesthetic agent bupivacaine was injected into the thoracic epidural space via a surgically introduced catheter. TEA markedly reduced heart rate, mean aortic blood pressure, left ventricular systolic blood pressure and dP/dtmax. TEA reduced the plasma concentration of FFA. The FFA-lowering effect was greatest when the FFA values were high. The effect of TEA on the plasma concentration of noradrenaline and adrenaline was inconsistent and seemed to be of minor importance for the haemodynamic and FFA effects of TEA. The study indicates that TEA, by its haemodynamic and FFA-lowering effects, may reduce myocardial oxygen demand.

Electrophysiological effects of thoracic epidural analgesia in the dog heart in situ.

To investigate cardiac electrophysiological effects of thoracic epidural analgesia, a local anaesthetic solution, 0.5% bupivacaine, was administered into the thoracic epidural space in twelve pentobarbital anaesthetised dogs. Intracardiac conduction times were measured by His bundle electrography and refractoriness was determined by programmed electrical stimulation. Monophasic action potentials were recorded from the right ventricle by a suction electrode technique. Thoracic epidural analgesia increased the ventricular effective and functional refractory period, as well as the duration of the monophasic action potential. The intra-atrial and His-Purkinje conduction times and the QRS-width were not significantly influenced. AV nodal conduction time and AV nodal functional refractory period were markedly prolonged by thoracic epidural analgesia. Thoracic epidural analgesia induced AV block of the second degree in most experiments after a second dose of bupivacaine during pacing at higher frequencies. We conclude that thoracic epidural analgesia has significant cardiac electrophysiological effects which may be both antiarrhythmic and arrhythmogenic. Thoracic epidural analgesia should be used with care in patients with atrioventricular conduction disturbances.