Brain Health After COVID-19, Pneumonia, Myocardial Infarction, or Critical Illness

Importance

Brain health is most likely compromised after hospitalization for COVID-19; however, long-term prospective investigations with matched control cohorts and face-to-face assessments are lacking.

Objective

To assess whether long-term cognitive, psychiatric, or neurological complications among patients hospitalized for COVID-19 differ from those among patients hospitalized for other medical conditions of similar severity and from healthy controls.

Design, Setting, and Participants

This prospective cohort study with matched controls was conducted at 2 academic hospitals in Copenhagen, Denmark. The case cohort comprised patients with COVID-19 hospitalized between March 1, 2020, and March 31, 2021. Control cohorts consisted of patients hospitalized for pneumonia, myocardial infarction, or non-COVID-19 intensive care-requiring illness between March 1, 2020, and June 30, 2021, and healthy age- and sex-matched individuals. The follow-up period was 18 months; participants were evaluated between November 1, 2021, and February 28, 2023.

Exposures

Hospitalization for COVID-19.

Main Outcomes and Measures

The primary outcome was overall cognition, assessed by the Screen for Cognitive Impairment in Psychiatry (SCIP) and the Montreal Cognitive Assessment (MoCA). Secondary outcomes were executive function, anxiety, depressive symptoms, and neurological deficits.

Results

The study included 345 participants, including 120 patients with COVID-19 (mean [SD] age, 60.8 [14.4] years; 70 men [58.3%]), 125 hospitalized controls (mean [SD] age, 66.0 [12.0] years; 73 men [58.4%]), and 100 healthy controls (mean [SD] age, 62.9 [15.3] years; 46 men [46.0%]). Patients with COVID-19 had worse cognitive status than healthy controls (estimated mean SCIP score, 59.0 [95% CI, 56.9-61.2] vs 68.8 [95% CI, 66.2-71.5]; estimated mean MoCA score, 26.5 [95% CI, 26.0-27.0] vs 28.2 [95% CI, 27.8-28.6]), but not hospitalized controls (mean SCIP score, 61.6 [95% CI, 59.1-64.1]; mean MoCA score, 27.2 [95% CI, 26.8-27.7]). Patients with COVID-19 also performed worse than healthy controls during all other psychiatric and neurological assessments. However, except for executive dysfunction (Trail Making Test Part B; relative mean difference, 1.15 [95% CI, 1.01-1.31]), the brain health of patients with COVID-19 was not more impaired than among hospitalized control patients. These results remained consistent across various sensitivity analyses.

Conclusions and Relevance

This prospective cohort study suggests that post-COVID-19 brain health was impaired but, overall, no more than the brain health of patients from 3 non-COVID-19 cohorts of comparable disease severity. Long-term associations with brain health might not be specific to COVID-19 but associated with overall illness severity and hospitalization. This information is important for putting understandable concerns about brain health after COVID-19 into perspective.

Neuropsychiatric and Cognitive Outcomes in Patients 6 Months After COVID-19 Requiring Hospitalization Compared With Matched Control Patients Hospitalized for Non-COVID-19 Illness

Importance

Prolonged neuropsychiatric and cognitive symptoms are increasingly reported in patients after COVID-19, but studies with well-matched controls are lacking.

Objective

To investigate cognitive impairment, neuropsychiatric diagnoses, and symptoms in survivors of COVID-19 compared with patients hospitalized for non-COVID-19 illness.

Design, Setting, and Participants

This prospective case-control study from a tertiary referral hospital in Copenhagen, Denmark, conducted between July 2020 and July 2021, followed up hospitalized COVID-19 survivors and control patients hospitalized for non-COVID-19 illness, matched for age, sex, and intensive care unit (ICU) status 6 months after symptom onset.

Exposures

Hospitalization for COVID-19.

Main Outcomes and Measures

Participants were investigated with the Mini-International Neuropsychiatric Interview, the Montreal Cognitive Assessment (MoCA), neurologic examination, and a semi-structured interview for subjective symptoms. Primary outcomes were total MoCA score and new onset of International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) psychiatric diagnoses. Secondary outcomes included specific psychiatric diagnoses, subjective symptoms, and neurologic examination results. All outcomes were adjusted for age, sex, ICU admission, admission length, and days of follow-up. Secondary outcomes were adjusted for multiple testing.

Results

A total of 85 COVID-19 survivors (36 [42%] women; mean [SD] age 56.8 [14] years) after hospitalization and 61 matched control patients with non-COVID-19 illness (27 [44%] women, mean age 59.4 years [SD, 13]) were enrolled. Cognitive status measured by total geometric mean MoCA scores at 6-month follow-up was lower (P = .01) among COVID-19 survivors (26.7; 95% CI, 26.2-27.1) than control patients (27.5; 95% CI, 27.0-27.9). The cognitive status improved substantially (P = .004), from 19.2 (95% CI, 15.2-23.2) at discharge to 26.1 (95% CI, 23.1-29.1) for 15 patients with COVID-19 with MoCA evaluations from hospital discharge. A total of 16 of 85 patients with COVID-19 (19%) and 12 of 61 control patients (20%) had a new-onset psychiatric diagnosis at 6-month follow-up, which was not significantly different (odds ratio, 0.93; 95% CI, 0.39-2.27; P = .87). In fully adjusted models, secondary outcomes were not significantly different, except anosmia, which was more common after COVID-19 (odds ratio, 4.56; 95% CI, 1.52-17.42; P = .006); but no longer when adjusting for multiple testing.

Conclusions and Relevance

In this prospective case-control study, cognitive status at 6 months was worse among survivors of COVID-19, but the overall burden of neuropsychiatric and neurologic signs and symptoms among survivors of COVID-19 requiring hospitalization was comparable with the burden observed among matched survivors hospitalized for non-COVID-19 causes.

Central and peripheral nervous system complications of COVID-19: a prospective tertiary center cohort with 3-month follow-up

OBJECTIVE

To systematically describe central (CNS) and peripheral (PNS) nervous system complications in hospitalized COVID-19 patients.

METHODS

We conducted a prospective, consecutive, observational study of adult patients from a tertiary referral center with confirmed COVID-19. All patients were screened daily for neurological and neuropsychiatric symptoms during admission and discharge. Three-month follow-up data were collected using electronic health records. We classified complications as caused by SARS-CoV-2 neurotropism, immune-mediated or critical illness-related.

RESULTS

From April to September 2020, we enrolled 61 consecutively admitted COVID-19 patients, 35 (57%) of whom required intensive care (ICU) management for respiratory failure. Forty-one CNS/PNS complications were identified in 28 of 61 (45.9%) patients and were more frequent in ICU compared to non-ICU patients. The most common CNS complication was encephalopathy (n = 19, 31.1%), which was severe in 13 patients (GCS ≤ 12), including 8 with akinetic mutism. Length of ICU admission was independently associated with encephalopathy (OR = 1.22). Other CNS complications included ischemic stroke, a biopsy-proven acute necrotizing encephalitis, and transverse myelitis. The most common PNS complication was critical illness polyneuromyopathy (13.1%), with prolonged ICU stay as independent predictor (OR = 1.14). Treatment-related PNS complications included meralgia paresthetica. Of 41 complications in total, 3 were para/post-infectious, 34 were secondary to critical illness or other causes, and 4 remained unresolved. Cerebrospinal fluid was negative for SARS-CoV-2 RNA in all 5 patients investigated.

CONCLUSION

CNS and PNS complications were common in hospitalized COVID-19 patients, particularly in the ICU, and often attributable to critical illness. When COVID-19 was the primary cause for neurological disease, no signs of viral neurotropism were detected, but laboratory changes suggested autoimmune-mediated mechanisms.

Experience from multidisciplinary follow-up on critically ill patients treated in an intensive care unit

INTRODUCTION

International literature describes that former intensive care unit (ICU) patients suffer considerable physical and neuropsychological complications. Systematic data on Danish ICU survivors are scarce as standardised follow-up after intensive care has yet to be described. This article describes and evaluates the knowledge gained from outpatient follow-up at a tertiary intensive care unit at Rigshospitalet, Copenhagen, during a three-year period.

METHODS

A total of 101 adult former ICU patients attended the outpatient clinic over a three-year period. Patients included were medical and surgical patients with a length of stay exceeding four days. Patients attended the clinic after discharge from hospital and for a minimum of two months from their discharge from the ICU. The patients were assessed for physical, neuropsychological and psychological problems and, if necessary, further treatment or rehabilitation was initiated.

RESULTS

Reduced physical ability was seen in 82%. A total of 89% suffered a substantial weight loss. 83.2% had signs indicating acute brain dysfunction during the ICU stay, and approximately half of the patients still had cognitive problems. A total of 66 interventions were initiated.

CONCLUSION

Our data confirmed that a large proportion of ICU survivors suffer considerable long-term physical and neuropsychological sequelae. Intensive care follow-up may contribute to address these specific problems and to initiate the needed interventions. Research is needed to determine whether specialised rehabilitation is required.

FUNDING

not relevant.

TRIAL REGISTRATION

not relevant.

Danish national sedation strategy. Targeted therapy of discomfort associated with critical illness. Danish Society of Intensive Care Medicine (DSIT) and the Danish Society of Anesthesiology and Intensive Care Medicine (DASAIM)

Sedation of critically ill patients undergoing mechanical ventilation should be minimized or completely avoided. Only in selected situations is sedation indicated as first line therapy (increased intracranial pressure or therapeutic hypothermia). The critical care physicians primary objective should be to focus on the reversible causes of agitation, such as: pain, anxiety, delirium, dyspnea, withdrawal symptoms, sleep or gastrointestinal symptoms. If sedation is used a validated sedation scale is recommended. On a daily basis sedation should be interrupted and only restarted after a thorough search for reversible causes of discomfort and stress.

Ketogenic diet in 3 cases of childhood refractory status epilepticus

INTRODUCTION

Refractory status epilepticus (RSE) in children is associated with a significant risk of death or neurological morbidity. Recently attention has been drawn to the ketogenic diet (KD) as an acute treatment, as it has shown promise in controlling seizures in otherwise refractory status epilepticus in several cases. We have listed these and reviewed all cases of KD used in RSE at our centre. KD was given as 4:1 fat:carbohydrate-protein solution.

RESULTS

A 3-year-old girl with RSE due to Hemiconvulsion-Hemiplegia Epilepsy syndrome. KD was instigated on day 6. Seizures stopped with ketosis on day 7. A 10-year-old boy rapidly developing RSE. After months a mitochondrial disorder was discovered. KD was tried twice with severe side-effects but no seizure control. 11-year-old healthy boy with RSE as FIRES. On KD seizures stopped for 24 h one day after reaching ketosis. He improved over 3-4 weeks.

DISCUSSION

KD was efficient in two of three cases of RSE. The non-responder had severe side-effects and proved to have a mitochondrial disorder which is arguably a contraindication for KD. More studies are needed to prove efficacy of KD in RSE, to define optimal timing of KD and possible contraindications for KD in RSE.

Circulating levels of vasoactive peptides in patients with acute bacterial meningitis

PURPOSE

The underlying mechanisms for cerebral blood flow (CBF) abnormalities in acute bacterial meningitis (ABM) are largely unknown. Putative mediators include vasoactive peptides, e.g. calcitonin-gene related peptide (CGRP), vasoactive intestinal peptide (VIP), and endothelin-1 (ET-1), all of which may be affected by therapeutic interventions used in the intensive care unit. We measured arterial levels as well as the net cerebral flux of these peptides in patients with ABM, and in healthy volunteers undergoing interventions relevant to intensive care.

METHODS

Seven patients with severe ABM and sepsis and fifteen healthy volunteers were included after informed consent. The net cerebral fluxes of vasoactive peptides were measured by the Kety-Schmidt technique in ABM patients (baseline study only), as well as in volunteers at baseline, during voluntary hyperventilation, after an intravenous injection of lipopolysaccharide (LPS), and during norepinephrine infusion.

RESULTS

The arterial levels of CGRP, but not of VIP or ET-1, were elevated in patients with ABM, but no net cerebral flux was present. CGRP levels decreased during hyperventilation and after LPS injection. No net cerebral flux of VIP occurred in any group at any time. A cerebral efflux of ET-1, which occurred in volunteers at baseline, was neither present in volunteers after LPS injection nor in patients with ABM.

CONCLUSION

The arterial concentration of the vasodilatory peptide, CGRP, but of neither VIP nor the vasoconstrictor ET-1, is elevated in patients with ABM and sepsis. A constitutive cerebral output of ET-1 appears to be present in healthy humans, but is abolished after LPS injection.

[Physical and neuropsychological sequelae after intensive therapy]

Until recently, critical care therapy practitioners have focused on survival rather than on long-term outcomes. The incidence of physical and neuropsychological dysfunction has been underestimated and underreported after acute critical care illness. Current research indicates that these sequelae are common, may be permanent, and are associated with decreased quality of life. More studies investigating the effects of treatment and rehabilitation therapy on sequelae after intensive therapy are required.

Endotoxemia stimulates skeletal muscle Na+-K+-ATPase and raises blood lactate under aerobic conditions in humans

We assessed the hypothesis that the epinephrine surge present during sepsis accelerates aerobic glycolysis and lactate production by increasing activity of skeletal muscle Na(+)-K(+)-ATPase. Healthy volunteers received an intravenous bolus of endotoxin or placebo in a randomized order on two different days. Endotoxemia induced a response resembling sepsis. Endotoxemia increased plasma epinephrine to a maximum at t = 2 h of 0.7 +/- 0.1 vs. 0.3 +/- 0.1 nmol/l (P < 0.05, n = 6-7). Endotoxemia reduced plasma K(+) reaching a nadir at t = 5 h of 3.3 +/- 0.1 vs. 3.8 +/- 0.1 mmol/l (P < 0.01, n = 6-7), followed by an increase to placebo level at t = 7-8 h. During the declining plasma K(+), a relative accumulation of K(+) was seen reaching a maximum at t = 6 h of 8.7 +/- 3.8 mmol/leg (P < 0.05). Plasma lactate increased to a maximum at t = 1 h of 2.5 +/- 0.5 vs. 0.9 +/- 0.1 mmol/l (P < 0.05, n = 8) in association with increased release of lactate from the legs. These changes were not associated with hypoperfusion or hypoxia. During the first 24 h after endotoxin infusion, renal K(+) excretion was 27 +/- 7 mmol, i.e., 58% higher than after placebo. Combination of the well-known stimulatory effect of catecholamines on skeletal muscle Na(+)-K(+)-ATPase activity, with the present confirmation of an expected Na(+)-K(+)- ATPase-induced decline in plasma K(+), suggests that the increased lactate release was due to increased Na(+)-K(+)-ATPase activity, supporting our hypothesis. Thus increased lactate levels in acutely and severely ill patients should not be managed only from the point of view that it reflects hypoxia.

Remifentanil vs. alfentanil for direct laryngoscopy: a randomized study comparing two total intravenous anaesthesia techniques. TIVA for direct laryngoscopy

The ideal anaesthesia for direct laryngoscopy is profound and yet brief. The present study sought to determine whether a new anaesthetic technique based on infusion of the ultra short-acting opioid remifentanil was superior to our routine alfentanil multiple-dose technique in terms of haemodynamic stability, stress responses and recovery. A total of 58 patients were randomized to receive propofol and either remifentanil or alfentanil as part of a total intravenous anaesthesia. In the remifentanil group, systolic blood pressure during anaesthesia remained significantly lower than baseline values, while it increased significantly in the alfentanil group. None of the patients receiving remifentanil showed stress responses (hypertension, tachycardia, somatic or autonomic responses), compared to 22 patients (79%) in the alfentanil group (P < 0.0001). In the remifentanil group, hypotension or bradycardia requiring intervention arose in 5 (18%) and 3 patients (11%); neither response was seen in the alfentanil group. The period from the end of propofol infusion until extubation was 5 min longer in the remifentanil group (P < 0.0001), whereas the time from extubation until discharge was similar in the two groups. Thus, neither technique showed sufficient haemodynamic stability, and further studies are needed to determine optimal dosages of propofol and opioid.

Randomized comparison of oxygen mask treatment vs. nasal continuous positive airway pressure in dengue shock syndrome with acute respiratory failure

Dengue hemorrhagic fever (DHF) is caused by dengue virus. Patients with DHF grade 3-4, termed Dengue Shock Syndrome (DSS), may develop acute respiratory failure after initial fluid resuscitation. Previously, these patients were treated with oxygen on a nasal cannula, or if necessary with tracheal intubation and mechanical ventilation. In the present prospective randomized study, we compared the effectiveness of oxygen treatment administered by a face mask vs. nasal continuous positive airway pressure (NCPAP). Morbidity, mortality, and supportive treatment was evaluated. Thirty-seven patients with DSS complicated by respiratory failure were enrolled. On admission and after 30 min of treatment, clinical and paraclinical data were obtained. Chest X-ray revealed pleural effusion in 92 per cent and showed interstitial oedema in 33 per cent. After 30 min of treatment the respiratory rate decreased significantly in the NCPAP group (p < 0.05), while SaO2 and PaO2 increased in both groups (p < 0.01). However, subsequently a significant difference of unresponsiveness to treatment between the oxygen mask group and the NCPAP group (13/19 vs. 4/18,p < 0.01) was noted. Complications of NCPAP or oxygen mask treatment were not documented. We conclude that NCPAP is useful in improving the management of acute respiratory failure in children with DHF/DSS in dengue-endemic areas.

Cerebral blood flow and oxidative metabolism during human endotoxemia

The proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), has been suggested to mediate septic encephalopathy through an effect on cerebral blood flow (CBF) and metabolism. The effect of an intravenous bolus of endotoxin on global CBF, metabolism, and net flux of cytokines and catecholamines was investigated in eight healthy young volunteers. Cerebral blood flow was measured by the Kety-Schmidt technique at baseline (during normocapnia and voluntary hyperventilation for calculation of subject-specific cerebrovascular CO reactivity), and 90 minutes after an intravenous bolus of a reference endotoxin. Arterial TNF-alpha peaked at 90 minutes, coinciding with a peak in subjective symptoms. At this time, CBF and Paco were significantly reduced compared to baseline; the CBF decrease was readily explained by hypocapnia. The cerebral metabolic rate of oxygen remained unchanged, and the net cerebral flux of TNF-alpha, interleukin (IL)-1beta, and IL-6 did not differ significantly from zero. Thus, high circulating levels of TNF-alpha during human endotoxemia do not induce a direct reduction in cerebral oxidative metabolism.

Activated T lymphocytes disappear from circulation during endotoxemia in humans

Seventeen volunteers received an intravenous bolus of endotoxin (2 ng/kg of body weight). Endotoxin-induced lymphopenia was constituted mainly by cells with an immature phenotype (CD45RA(+) CD45RO(-)) that were less likely to undergo apoptosis (CD28(+)), whereas cells with the highest rates of disappearance were characterized by an activated phenotype (CD45RA(-) CD45RO(+)) as well as a phenotype linked to apoptosis (CD95(+) CD28(-)). In conclusion, endotoxin-induced lymphopenia reflects the disappearance from the circulation of activated lymphocytes prone to undergo apoptosis.

Prospective case-control study of encephalopathy in children with dengue hemorrhagic fever

We present a prospective case-control study of 27 serologically confirmed dengue hemorrhagic fever (DHF) patients with severe central nervous system symptoms. Dengue associated encephalopathy accounted for 0.5% of 5,400 patients admitted with DHF. The mortality rate among children with encephalopathy was 22%, with the survivors experiencing a complete recovery. Liver enzymes and bilirubin were significantly elevated in the study group. In analysis of the cerebrospinal fluid (CSF), reverse transcriptase-polymerase chain reaction revealed dengue-3-specific RNA in one evaluated case. Dengue-specific immunoglobulin M was detected in CSF in 14 of 22 assessable patients, indicating a localized infection. Magnetic resonance imaging scans showed cerebral edema in the majority of patients, although encephalitis-like changes were less common. There was an equal distribution of primary and secondary infections. On the basis of previous reports and of the findings of our study, DHF probably encompasses an expanding clinical spectrum that infrequently involves encephalitis due to a direct neurotropic effect of dengue virus.

Hypotension during endotoxemia in aged humans

BACKGROUND

and objective The aim of this study was to determine possible age-associated differences in human blood pressure regulation during an immunological challenge in healthy subjects.

METHODS

Eight healthy young volunteers (median age 24 yr) and nine healthy elderly volunteers (median age 66 yr) received an intravenous bolus injection of Escherichia coli endotoxin (2 ng kg(-1)). Blood pressure, heart rate and core temperature were monitored during the first 7 h. Plasma catecholamine concentrations were measured at hourly intervals.

RESULTS

The elderly showed a significantly more pronounced decrease in mean arterial pressure 4-7 h after endotoxin administration compared with the young controls (ANOVA; age x time; P < 0.0005). This mainly reflected a decrease in the systolic blood pressure in the elderly. The heart rate of both groups increased without difference between groups. Increased plasma epinephrine concentrations were found 2-3 h after endotoxin administration in both groups. Five hours after the endotoxin challenge, the epinephrine concentration had returned to control values in the elderly group only, in spite of decreased blood pressure.

CONCLUSION

In conclusion, healthy elderly subjects fail to maintain a constant mean arterial pressure in response to the immunological challenge of endotoxemia.

Ageing is associated with a prolonged fever response in human endotoxemia

The purpose of this study was to investigate whether an age-associated impaired acute-phase response exists. Nine healthy elderly volunteers (median, 66 years; range, 61 to 69 years) and eight young controls (median, 24 years; range, 20 to 27 years) were given an intravenous bolus of endotoxin (2 ng/kg). The rectal temperature was monitored continuously, and blood samples for cytokine measurements were obtained before endotoxin administration as well as 0.5, 1, 1.5, 2, 3, 4, 8, 12, and 24 h after the injection. The elderly subjects showed a more prolonged fever response compared to the young controls. Levels of tumor necrosis factor alpha (TNF-alpha), soluble TNF receptors (sTNFR-I), interleukin-6 (IL-6), IL-8, IL-10, and IL-1 receptor antagonist (IL-1ra) in plasma increased markedly following endotoxin administration in both groups. The elderly group showed larger initial increases in TNF-alpha and sTNFR-I levels and prolonged increased levels of sTNFR-I. Monocyte concentrations decreased in both groups, with the elderly group showing a more rapid decrease and a slower subsequent increase than did the young group. Furthermore, the elderly group had a more rapid increase in C-reactive protein levels than did the young group. In conclusion, ageing is associated with an altered acute-phase response including initial hyperreactivity, prolonged inflammatory activity, and prolonged fever response.

[Dengue fever and dengue hemorrhagic fever]

Dengue virus is transmitted by mosquitoes and causes dengue fever/dengue haemorrhagic fever throughout the tropical areas of the world. There is an increasing incidence of dengue infections. Because of increasing travel activity, infection among Danes travelling abroad as well as imported cases are expected to be seen more frequently. In this review we describe the clinical manifestations, diagnosis, pathogenesis, treatment and prevention of the disease.

Occurrence of withdrawal in critically ill sedated children

OBJECTIVES

To record the number of children with withdrawal symptoms after the administration of sedatives for mechanical ventilation, and to discuss the possible connection with the administration of midazolam.

DESIGN

Retrospective data collection from case records and charts.

SETTING

Medical and surgical intensive care unit (ICU) in a university hospital.

PATIENTS

Children 6 months to 14 yrs of age who required sedation for mechanical ventilation (n = 40).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Kind and amount of sedatives and analgesics, duration of administration, and occurrence of withdrawal symptoms. The frequency of withdrawal symptoms was 35% (14/40) of the sedated children. A total dose of midazolam of >60 mg/kg was strongly significantly associated with occurrence of withdrawal. Statistical analysis to determine the occurrence of withdrawal associated with the administration of morphine was not possible.

CONCLUSIONS

Signs and symptoms of a withdrawal reaction were observed in several children. The occurrence of withdrawal was statistically related to high doses of midazolam, but it was not possible to determine the influence of morphine. If large doses of midazolam and opioids have been administered, there may be justification for reducing the dose gradually instead of abruptly, or using longer-acting benzodiazepines or opioids on discontinuation of sedation.

[Sedation of children on respirators. A questionnaire study on therapeutic strategies and withdrawal problems]

The purpose of this study was to identify the patterns of use of sedative agents and withdrawal problems in the paediatric intensive care unit (PICU). A questionnaire survey was mailed to 46 Danish intensive care units. Only 24 of these treated paediatric patients needing mechanical ventilation. The agents most frequently employed were morphine and midazolam. There was general satisfaction with the used drugs. The majority of departments noted that there was no protocol for sedation in their PICU. The majority of departments (70.8%) did not consider drug withdrawal to be a problem, but those departments who treated most children considered drug withdrawal to be a problem.

[Influence of various therapeutic models on survival after prehospital cardiac arrest]

We analyzed the outcome after prehospital cardiac arrest in a part of greater Copenhagen. Four different emergency medical systems were acting: a system providing basic life support only (group 1), a system providing basic life support and early defibrillation (group 2), a system providing basic life support followed by advanced cardiac life support (group 3), and a system providing basic life support and early defibrillation followed by advanced cardiac life support (group 4). Over a 2-year period 624 cases of cardiac arrest were reported, 34 were discharged from hospital. The survival to discharge from hospital and the one-year survival were significantly better in group 4. Our data reconfirm that early advanced cardiac life support improves survival rates for prehospital cardiac arrest.

Isorhythmic atrioventricular dissociation following pancuronium

We report a case of isorhythmic atrio-ventricular dissociation caused by pancuronium. The possible mechanism of the rhythm disorder is discussed and the haemodynamic consequences are described. It will be useful to realise that the circulatory effects of the arrhythmia may be pronounced in patients with decreased cardiovascular reserve.

[Temporary pacing in connection with anesthesia. Indications and methods]

The indications for permanent pacing are, by and large, established. Considerable uncertainty still exists about when temporary pacing should be initiated not least in connection with anaesthesia and surgery. The indications for temporary pacemaker treatment are reviewed and, in addition, the two methods of temporary pacemaker treatment are discussed, viz the transvenous and the transcutaneous method.

[Treatment of cardiac arrest outside of the hospital with a semiautomatic defibrillator--Heartstart 2000]

In order to test the efficacy of a semiautomatic defibrillator (Heartstart 2000) in connection with cardiac arrest outside hospital, the apparatus was installed in two of the ambulances belonging to the Copenhagen Fire Service. The ambulance district involved was also equipped with an ambulance staffed by a doctor. A total of 48 patients with cardiac arrest were found and 16 of these had ventricular fibrillation. Six of the 16 patients have since been discharged from hospital (37.5%). The defibrillator had a high diagnostic certainty with a sensitivity of 96.5% and a specificity of 100%. No practical problems of note occurred in connection with employment of the defibrillator. The ambulance staffs underwent six hours of training and this appeared to be adequate. It is concluded that Heartstart 2000 functions well and effectively in connection with revival of patients with cardiac arrest outside hospital.

Use of vecuronium and doxapram in patients susceptible to malignant hyperthermia

Neuromuscular blockade was obtained with vecuronium 108 micrograms kg-1 in 44 patients undergoing diagnostic muscle biopsy as part of an investigation of malignant hyperthermia (MH) susceptibility. At the termination of anaesthesia doxapram 1.43 mg kg-1 was given in an attempt to antagonize postoperative respiratory depression. Rectal, muscle and skin temperatures, blood lactate concentration and venous PCO2 were measured before, during and after anaesthesia. Susceptibility to MH was established by in vitro contracture tests according to the protocol of the European MH Group. Twenty patients were susceptible to MH (MHS), 19 were MH non-susceptible (MHN) and five MH equivocal (MHE). No adverse effects of the drugs were observed. There were no differences between the three groups in rectal or muscle temperature, blood lactate concentration or venous PCO2 at any time. Doxapram did not prevent an increase in postoperative PCO2. It is concluded that vecuronium and doxapram may be safely administered to patients susceptible to MH.