Sevoflurane-induced malignant hyperthermia during cardiopulmonary bypass and moderate hypothermia.

A 56-year old man was admitted for elective mitral valve repair and coronary artery bypass surgery due to mitral valve leakage and unstable angina. After induction of anaesthesia he developed a combined metabolic and respiratory acidosis. Different diagnosis were considered and we decided to treat the patient with dantrolene due to suspicion of malignant hyperthermia (MH). The patient received one dose of dantrolene 2,5 mg/kg during cardiopulmonary bypass (CPB) and a second dose of dantrolene 2,5 mg/kg during weaning from CPB. The first arterial blood gas sample taken in the intensive care unit showed relapse of the acidosis and we administered an infusion of 150 mg dantrolene over 3 hours. The patient gradually recovered without sequel and MH was verified by muscle biopsy testing.

Increased spillover of norepinephrine to the portal vein during CO-pneumoperitoneum in pigs.

BACKGROUND: Elevated intra abdominal pressure (IAP) during CO2-insufflation has been associated with increased catecholamine concentrations in plasma. We have previously indicated that this may be due to a regional increased spillover from the abdominal region. In this experimental study we investigated catecholamine spillover from the drainage area of the portal vein during CO2-pneumoperitoneum. METHODS: Eight pigs under general anesthesia were investigated before and after CO2-pneumoperitoneum with an IAP of 15 mmHg. Regional spillover of catecholamines was determined by measuring plasma catecholamine concentrations and flow simultaneously. Plasma concentrations of catecholamines were measured from the portal and femoral veins, the pulmonary and carotid arteries. Flow data were collected with laser-Doppler transit time flow probes around the portal and femoral veins. Cardiac output was measured by the thermo-dilution technique. Estimated spillover was calculated by the veno-arterial difference multiplied by flow. RESULTS: We found a significant increase in estimated spillover of norepinephrine from the drainage area of the portal vein from 10 (-1.2, 78) ng x min(-1) to 27 (1.8, 475) ng x min(-1)[median (range)] (P = 0.05), but no change in estimated spillover of norepinephrine from the drainage area of the femoral vein. Plasma concentrations of norepinephrine increased in central venous and arterial blood. There was no significant change in epinephrine concentrations in arterial blood. CONCLUSION: Estimated norepinephrine spillover from the drainage area of the portal vein increased during CO2-pneumoperitoneum in pigs. This may indicate that the increased norepinephrine concentrations found in arterial plasma reflects a local activation of sympathetic nerves in the region of the portal drainage area.

Catecholamine release during laparoscopic fundoplication with high and low doses of remifentanil.

BACKGROUND: Reports on stress responses to laparoscopic surgery have been conflicting. Depth of anesthesia may influence the neuro-hormonal release, including catecholamines. Opioids depress general sympathetic activation in a dose-dependent manner. We investigated the hypothesis that remifentanil would depress the catecholamine response to pneumoperitoneum and laparoscopic surgery differently with a high dose (HD) compared with a low dose (LD). METHODS: In a randomized, prospective study we investigated 18 ASA I-II patients undergoing laparoscopic fundoplication with an intra-abdominal pressure of 12 mmHg. The patients were randomized to receive either a LD (0.13 microg kg-1x min-1) or HD (0.39 microg kg-1 x min-1) of remifentanil with a target-controlled infusion (TCI) technique. Bispectral index of EEG (BIS) was maintained at 40-55 by propofol delivered by a TCI system. Arterial catecholamines were analyzed at different times during the procedure. RESULTS: Norepinephrine increased equally in both groups during pneumoperitoneum and surgical intervention. Epinephrine stayed low in the HD-group, while increasing during surgery in the LD-group. CONCLUSION: High dose of remifentanil depressed the epinephrine response to pneumoperitoneum and surgery, indicating no general activation of the sympathetic nervous system. Neither a LD nor HD of remifentanil depressed the norepinephrine response during pneumoperitoneum. This suggests a centrally independent release of norepinephrine.

Skin conductance correlates with perioperative stress.

BACKGROUND: Skin conductance (SC) as a measure of emotional state or arousal may be a tool for monitoring surgical stress in anaesthesia. When an outgoing sympathetic nervous burst occurs to the skin, the palmar and plantar sweat glands are filled up, and the SC increases before the sweat is removed and the SC decreases. This creates a SC fluctuation. The purpose of this study was to measure SC during laparoscopic cholecystectomy with propofol and remifentanil anesthaesia and to evaluate whether number and amplitude of SC fluctuations correlate with perioperative stress monitoring. METHODS: Eleven patients were studied nine times before, during and after anaesthesia. SC was compared to changes in stress measures such as blood pressure, heart rate, norepinephrine and epinephrine levels. SC was also compared to changes in Bispectral index (BIS). RESULTS: The blood pressure, epinephrine levels and norepinephrine levels were positively correlated with both the number (P < 0.001) and amplitude (P < 0.01) of the SC fluctuations. Moreover, the BIS was positively correlated with the number (P < 0.001) and amplitude (P < 0.001) of the SC fluctuations. Furthermore, during tracheal intubation, the mean levels of the number of SC fluctuations from the 11 patients had the same stress response as measured in changes of the mean levels of norepinephrine. The mean BIS did not show any stress response during tracheal intubation. CONCLUSION: Number of SC fluctuations may be a useful method for monitoring the perioperative stress.

[Activity registration in intensive care units]. / Virksomhetsregistrering ved intensivavdelinger.

Intensive care treatment is expensive and its capacity is limited. The population of elderly patients with greater need for intensive care increases. It has become more important to evaluate the use of intensive care resources and to compare it with the results of treatment. Diagnoses do not provide a satisfactory description of the stay in the intensive care unit. Scoring systems for severity of illness and for resource needs are therefore of great value. The Norwegian Board of Health has requested all intensive care units in Norway to describe their activities by scoring systems for severity of illness, SAPS II (Simplified Acute Physiology Score II) and for use of resources NEMS (Nine Equivalents of Nursing Manpower Use Score). The systems are generally well recognised, easy to learn and not time-consuming. Through SAPS II and NEMS it is possible to compare results of treatment and use of resources across intensive care units or against a standard.

[Experiences with scoring systems SAPS II and NEMS for registration of activities in an intensive care unit]. / Erfaringer med bruk av skåringssystemene SAPS II og NEMS i virksomhetsregistrering i en intensivavdeling.

BACKGROUND: Intensive care is highly expensive, hence the requirement of efficient use of resources calls for evaluation of the severity of disease or injury for each individual patient, so that management may be optimised. MATERIAL AND METHODS: At Ullevaal University Hospital, two different scoring systems have been used since 1996: SAPS II (Simplified Acute Physiology Score) for severity of illness and NEMS (Nine Equivalents of Nursing Manpower Use Score) for assessment of resource utilisation. RESULTS: A significant relationship between severity of illness and mortality was found. Length of stay in ICU correlated with increasing SAPS II score in the range 0 to 50, but at higher scores no relationship was found. Patients with trauma and cardiovascular surgical patients used most of the resources. 79% of total NEMS score consisted of vital signs monitoring, intravenous drug medication and mechanical ventilation of the patients. INTERPRETATION: SAPS II and NEMS scoring systems provide useful information needed in the assessment of patient care in the ICU and are helpful in the documentation of financial and medical resource needs.

[Prehospital treatment of heroin intoxication in Oslo in 1996]. / Prehospital behandling av heroinforgiftning i Oslo i 1996.

The number of heroin overdoses among drug addicts in Oslo is increasing. In 1996 overdoses counted for 1,248 (12%) of all emergency call-outs by the ambulance service. Heroin can cause fatal respiratory insufficiency, and in 1996 a total of 104 deaths related to heroin overdoses were reported in Oslo. Heroin overdoses are treated on site by ambulance personnel. Advanced cardiopulmonary resuscitation was started on 18 of the 79 addicts who were found unconscious, and 11 persons were treated successfully. A total of 846 drug addicts had to be given the antidote naloxone, and among these 678 (80%) persons were found in a coma. Only 29 persons had to be transported to hospital. Early treatment probably prevented both morbidity and mortality, no time being wasted transporting the patients to hospital. Ambulance personnel treat all drug addicts with the same respect as they do other patients. They have no police escort; they are familiar with the addicts and their environment and they have gained their confidence. Prehospital treatment saves on health services resources, and should, in our experience, be carried out in collaboration with a hospital or other health institutions for mutual and optimal benefit.

Plasma catecholamines and haemodynamic changes during pneumoperitoneum.

BACKGROUND: Insufflation of CO2 into the abdomen is used during all kinds of laparoscopic operations. The procedure elicits haemodynamic and hormonal responses. The reports on sympathetic responses to laparoscopic surgery have been conflicting. However, few studies have assessed sympathetic and haemodynamic responses to CO2 insufflation per se, eliminating possible effects of intubation, skin incision, surgical manipulation and positioning of the body. No studies have measured both venous and arterial plasma catecholamines, the latter being a more sensitive indicator of sympathetic activity. In the present study, we hypothesised an increased sympathetic activity during pneumoperitoneum and an association between haemodynamic and sympathetic responses. METHODS: Plasma adrenaline and noradrenaline from the radial artery and superior vena cava were measured immediately before and 10 min after abdominal insufflation of CO2 in 11 subjects. Haemodynamics were monitored invasively. RESULTS: During pneumoperitoneum arterial plasma noradrenaline increased from 155 (106, 209) pg/ml (median, lowest and highest quartile) to 283 (188, 378) pg/ml (P = 0.003), while there were no changes in arterial plasma adrenaline. The calculated arterial-superior vena cava difference in plasma noradrenaline did not change, indicating no increased sympathetic activity in the drainage area of the superior vena cava. Heart rate and cardiac index were unchanged, while total peripheral resistance and mean arterial blood pressure increased (P = 0.002). The changes in arterial plasma noradrenaline were closely related to the changes in total peripheral resistance (r = 0.69, P = 0.01). CONCLUSIONS: Plasma noradrenaline increases during pneumoperitoneum and is associated with changes in total peripheral resistance. Plasma adrenaline is unchanged and there is no evidence of increased sympathetic outflow to the drainage area of the superior vena cava. Thus, the increase in plasma noradrenaline may be due to more local activation of the sympathetic nervous system, probably somewhere from the drainage area of the inferior vena cava.

[Digitalis poisoning treated with a specific antidote]. / Digitalisforgiftning behandlet med spesifikt antidot.

Toxicity by digitalis is a common problem in everyday clinical practice. In this paper three cases of severe poisoning with digitoxin with maximal S-digitoxin levels of 115, 150 and 239 nmol/l are described. All patients received specific digoxin Fab-fragment intravenously. Administration of antidotes resulted in a favourable outcome in all three patients. So far, the use of digoxin-specific antibodies has been limited to a few cases of severe intoxication where life-threatening arrhythmias and hyperkalaemia were present. We discuss whether a more liberal indication should be accepted.

Simultaneous hemodynamic and echocardiographic changes during abdominal gas insufflation.

The purpose of this study was to investigate cardiovascular changes during CO2 pneumoperitoneum. We performed simultaneous hemodynamic recordings and transesophageal echocardiographic measurements of possible alterations in cardiac dimensions. Seven patients scheduled for elective laparoscopic cholecystectomy were investigated. With an intraabdominal pressure of 15 mm Hg, mean arterial pressure increased from 75 to 93 mm Hg (p < 0.05). Despite the increase in pulmonary capillary wedge pressure (PCWP) from 10 (9.5-12) to 17 (16-19.9) mm Hg (p < 0.05), left ventricular end-diastolic area index (EDAI) did not change significantly. The cardiac index remained unchanged. Thus abdominal gas insufflation substantially alters the PCWP/EDAI relation. During pneumoperitoneum, left ventricular filling pressure, estimated by PCWP, cannot be used as an indicator of left ventricular dilation.

Left ventricular mass and cardiovascular reactivity in young men.

The relation between left ventricular wall thickness and mass, arterial plasma catecholamines, and blood pressure at rest and during a mental arithmetic challenge and a cold pressor test was examined in 69 healthy men 19 years of age. The subjects were recruited from the 1st (n = 21), 50th (n = 26), and 99th (n = 22) percentiles in mean blood pressure. All underwent echocardiography to determine mean wall thickness and left ventricular mass. Continuous intra-arterial blood pressure, electrocardiogram, and arterial sampling of plasma catecholamines were performed after 30 minutes of supine rest, during a 5-minute mental arithmetic challenge, and during a 1-minute cold pressor test. Stepwise multiple-regression analyses considering mean wall thickness and left ventricular mass as the dependent variables were applied. Intra-arterial systolic blood pressure (r = .54, P < .0001) and arterial plasma epinephrine (r = .31, P = .009) after 30 minutes of supine rest were the only independent explanatory variables of mean wall thickness (multiple R2 = .33, P < .0001). Blood pressure at screening and during mental stress and cold pressor tests were not independent explanatory variables. The present study suggests that resting arterial blood pressure and plasma epinephrine may be of importance for development of left ventricular hypertrophy.

[Cardiopulmonary resuscitation attempts at Ullevål hospital during January 1989-July 1990]. / Hjerte-lunge-redningsforsøk ved Ullevål sykehus januar 1989-juli 1990.

During the period January 1989 to July 1990, 68 in-hospital cardiopulmonary resuscitations were attempted in 65 patients at Ullevål Hospital. The total number of deaths during the same period was 2,166. 21 patients survived initially (32%). Nine patients died later, and 12 patients (18%) were discharged from hospital without major cerebral disability. Six patients were alive at follow-up 13-25 months after cardiopulmonary resuscitation. No differences in survival were found between males and females, or between patients under and over 70 years of age.

Effects of increased splenic arterial flow and venous pressure on splenic red cell accumulation.

The importance of increments in splenic venous pressure (SVP) and splenic arterial flow (SAF) for splenic red cell accumulation was estimated in 14 anesthetized dogs with the spleen in situ by arterial and splenic venous hematocrit measurements and continuous ultrasonic recording of splenic diameter (SD). A 10-mmHg increase in SVP by 4 min of splenic venous constriction reduced SAF by 32 +/- 5%, increased SD by 5.1 +/- 0.8%, and transiently reduced splenic venous hematocrit, measured every 10 s, from 35.4 +/- 1.4 to a minimum of 29.2 +/- 1.8%. A 10-mmHg rise in SVP by 4 min of saline infusion increased SAF by 178 +/- 25% and SD by 16.1 +/- 3.0%, and splenic venous hematocrit declined more rapidly and to a lower value than arterial hematocrit. Blood volume expansion with saline or blood at constant, 10-mmHg elevated SVP confirmed that splenic red cell accumulation was greater during blood volume expansion than during splenic venous constriction. We conclude that the spleen accumulates red cells when SVP is raised. At constant, elevated SVP splenic red cell accumulation is flow dependent.

Angiotensin II infusion during beta-adrenergic stimulation by isoproterenol. Effects on hepatic, splenic and cardiac blood volumes and on the magnitude and distribution of cardiac output in the dog.

The cardiac and peripheral vascular adjustments to angiotensin II (0.1-0.2 microgram kg-1 min-1 i.v.) during high beta-adrenergic activity by a continuous isoproterenol infusion (0.2-0.3 microgram kg-1 min-1 i.v.) were examined in anaesthetized, atropinized dogs. Hepatic, splenic and left ventricular (LV) volume changes were estimated by an ultrasonic technique, and the blood flow distribution was measured by injecting radioactive microspheres and by electromagnetic flowmetry on the caval veins, the hepatic artery and the portal vein. During isoproterenol infusion, angiotensin II increased the systolic LV pressure by 45 +/- 3 mmHg and the stroke volume by 17 +/- 6%. Concomitantly, the hepatic and splenic blood volumes declined by 29 +/- 4 and 14 +/- 6 ml, respectively, and the LV end-diastolic segment length increased by 3 +/- 1%. The flow through the inferior caval vein increased by 39 +/- 9%, whereas the superior vena caval flow remained unchanged. The hepatic arterial flow more than doubled. Thus, at high inotropy by isoproterenol infusion, angiotensin II relocates blood from the liver and the spleen towards the heart. By activating the Frank-Starling mechanism, cardiac output is increased and conducted through the lower body, especially through the hepatic artery, because of the poor autoregulation of flow through this vessel.

Cardiopulmonary blood volume during acute blood pressure elevations in dogs.

During aortic blood flow obstructions and angiotensin infusion blood may be accumulated in the heart and the lungs because of retention or redistribution of blood from compliant regions. We measured the cardiopulmonary blood volume (CPBV) when left ventricular systolic pressure was raised by about 50 mmHg by angiotensin infusion and by balloon inflation in the ascending and descending thoracic aorta, at control inotropy and during isoproterenol infusion, in 6 anesthetized, closed-chest dogs. CPBV was calculated from determinations of cardiac output (thermodilution) and the interventricular mean transit time of ascorbate (polarographic determination). Angiotensin always increased CPBV, but the rise was greater at high than at control inotropy (16.5 +/- 4.4% and 5.1 +/- 1.2%). Balloon inflation in the descending thoracic aorta increased CPBV similarly at high and control inotropy (11.1 +/- 2.4% and 16.6 +/- 4.0%) whereas CPBV was unaltered or fell during inflation in the ascending aorta at both inotropic levels. Right and left ventricular end-diastolic pressures rose only during angiotensin infusion and balloon inflation in the descending thoracic aorta. By balloon inflation, cardiac output only fell during blood flow obstruction in the ascending aorta. Thus, an increase in CPBV during these interventions is not due to retention but is caused by redistribution of blood towards the heart.

Factors contributing to blood pressure elevation during norepinephrine and phenylephrine infusions in dogs.

To examine the factors contributing to the rise in systemic blood pressure during alpha- and beta-adrenergic stimulation, phenylephrine, an alpha-adrenergic agonist, and norepinephrine, an alpha- and beta-adrenergic agonist, were infused intravenously to anesthetized dogs until mean aortic blood pressure was raised equally by 40-60 mmHg. Changes in preload were estimated by changes in left ventricular end-diastolic pressure or segment length recorded by an ultrasonic technique. By obstructing the inferior vena cava (IVC), the increase in preload could be reduced to control level during phenylephrine and norepinephrine infusions without altering peripheral resistance (mean aortic blood pressure/cardiac output). Normalization of preload reduced the pressure response by 2/3 during phenylephrine infusion and by 1/4 during norepinephrine infusion. However, after beta-adrenergic blockade by propranolol, normalization of preload reduced the pressure response by 2/3 during both phenylephrine and norepinephrine infusions. Thus, during alpha-adrenergic stimulation, the increase in preload is a more important factor than the increase in peripheral resistance. Norepinephrine raised stroke volume by 24 +/- 5%. When the increase in stroke volume was prevented by IVC obstruction, the pressure response to norepinephrine was halved. Thus, during norepinephrine infusion the rise in stroke volume caused by beta-adrenergic stimulation is as important as alpha-adrenergic stimulation for the pressure response.