Deaths caused by injury among people of working age (18-64) are decreasing, while those among older people (64+) are increasing

Background

Injury is an important cause of death in all age groups worldwide, and contributes to many losses of human and economic resources. Currently, we know a few data about mortality from injury, particularly among the working population. The aim of the present study was to examine death from injury over a period of 14 years (1999–2012) using the Swedish Cause of Death Registry (CDR) and the National Patient Registry, which have complete national coverage.

Method

CDR was used to identify injury-related deaths among adults (18 years or over) during the years 1999–2012. ICD-10 diagnoses from V01 to X39 were included. The significance of changes over time was analyzed by linear regression.

Results

The incidence of prehospital death decreased significantly (coefficient −0.22, r² = 0.30; p = 0.041) during the study period, while that of deaths in hospital increased significantly (coefficient 0.20, r² = 0.75; p < 0.001). Mortality/100,000 person-years in the working age group (18–64 years) decreased significantly (coefficient −0.40, r² = 0.37; p = 0.020), mainly as a result of decrease in traffic-related deaths (coefficient −0.34, r² = 0.85; p < 0.001). The incidence of deaths from injury among elderly (65 years and older) patients increased because of the increase in falls (coefficient 1.71, r² = 0.84; p < 0.001) and poisoning (coefficient 0.13, r² = 0.69; p < 0.001).

Conclusion

The epidemiology of injury in Sweden has changed during recent years in that mortality from injury has declined in the working age group and increased among those people 64 years old and over.

Agreement between ambulance nurses and physicians in assessing stroke patients

OBJECTIVES

If an ambulance nurse could bypass the emergency department (ED) and bring suspected stroke patients directly to a CT scanner, time to thrombolysis could be shortened. This study evaluates the level of agreement between ambulance nurses and emergency physicians in assessing the need for a CT scan, and interventions and monitoring beforehand, in patients with suspected stroke and/or a lowered level of consciousness.

METHODS

From October 2008 to June 2009, we compared the ambulance nurses' and ED physicians' judgement of 200 patients with stroke symptoms. Both groups answered identical questions on patients' need for a CT scan, and interventions and monitoring beforehand.

RESULTS

There was poor agreement between ambulance nurses and ED physicians in judging the need for a CT scan: κ = 0.22 (95% confidence interval (CI), 0.06-0.37). The nurses' ability to select the same patients as the physician for a CT scan had a sensitivity of 84% (95% CI, 77-89) and a specificity of 37% (95% CI, 23-53). Agreement concerning the need for interventions and monitoring was also low: κ = 0.32 (95% CI, 0.18-0.47). In 18% of cases, the nurses considered interventions before a CT scan unnecessary when the physicians' deemed them necessary.

CONCLUSIONS

Additional tools to support ambulance nurses decisions appear to be required before suspected stroke patients can be taken directly to a CT scanner.

Popliteal artery injury during knee replacement

Popliteal artery injury (PAI) is a feared complication during knee replacement. Our aim was to investigate those injuries that occurred in association with knee replacement in terms of the type of injury, treatment and outcomes.

From our national vascular registry (Swedvasc) and the Swedish Patient Insurance databases a total of 32 cases were identified. Prospective data from the registries was supplemented with case-records, including long-term follow-up.

We estimated the incidence during 1998 to 2010 to be 0.017%. In our series of 32 patients with PAI occurring between 1987 and 2011, 25 (78%) were due to penetrating trauma and seven were caused by blunt trauma. The patients presented in three ways: bleeding (14), ischaemia (7) and false aneurysm formation (11), and five occurred during revision surgery. A total of 12 injuries were detected intra-operatively, eight within 24 hours (3 to 24) and 12 at more than 24 hours post-operatively (2 to 90 days). Treatment comprised open surgery in 28 patients. Patency of the vascular repair at 30 days was 97% (31 of 32, one amputation). At the time of follow-up (median 546 days, mean 677 days (24 to 1251)), 25 patients had residual symptoms. Of seven patients with a complete recovery, six had had an early diagnosis of the PAI during the procedure, and were treated by a vascular surgeon in the same hospital.

PAI is a rare adverse event during knee replacement surgery. The outcome following such events is often adversely affected by diagnostic and therapeutic delay. Bleeding and false aneurysm were the most common clinical presentations.

Cite this article: Bone Joint J 2013;95-B:1645–9.

Diagnosis-dependent misclassification of infections using administrative data variably affected incidence and mortality estimates in ICU patients

OBJECTIVE

To determine the accuracy of hospital discharge diagnoses in identifying severe infections among intensive care unit (ICU) patients, and estimate the impact of misclassification on incidence and 1-year mortality.

STUDY DESIGN AND SETTING

Sepsis, pneumonia, and central nervous system (CNS) infections among 7,615 ICU admissions were identified using ICD-9 and ICD-10 diagnoses from the Swedish hospital discharge register (HDR). Sensitivity, specificity, and likelihood ratios were calculated using ICU database diagnoses as reference standard, with inclusion in sepsis trials (IST) as secondary reference for sepsis.

RESULTS

CNS infections were accurately captured (sensitivity 95.4% [confidence interval (CI)=86.8-100] and specificity 99.6% [CI=99.4-99.8]). Community-acquired sepsis (sensitivity 51.1% [CI=41.0-61.2] and specificity 99.4% [CI=99.2-99.6]) and primary pneumonia (sensitivity 38.2% [CI=31.2-45.2] and specificity 98.6% [CI=98.2-99.0]) were more accurately detected than sepsis and pneumonia in general. One-year mortality was accurately estimated for primary pneumonia but underestimated for community-acquired sepsis. However, there were only small differences in sensitivity and specificity between HDR and ICU data in the ability to identify IST. ICD-9 appeared more accurate for sepsis, whereas ICD-10 was more accurate for pneumonia.

CONCLUSION

Accuracy of hospital discharge diagnoses varied depending on diagnosis and case definition. The pattern of misclassification makes estimates of relative risk more accurate than estimates of absolute risk.

Adrenaline administration during cardiopulmonary resuscitation: poor adherence to clinical guidelines

BACKGROUND

Adrenaline does not appear to improve the outcome after cardiac arrest in clinical trials in spite of beneficial effects in experimental studies. The objective of this study was to determine whether adrenaline was administered in accordance with advanced cardiac life support (ACLS) guidelines during adult cardiopulmonary resuscitation (CPR).

METHODS

From 15 January to 31 December 2000, all patients at Uppsala University Hospital in whom CPR was attempted were registered prospectively. The duration of CPR was documented in the register and the total dose of adrenaline was retrieved retrospectively from patient records. From these data the average interval between adrenaline doses was calculated.

RESULTS

Data for evaluation of the between-dose interval of adrenaline was available in 53 of 107 registered cardiac arrests. In 68% (36/53) the average between-dose interval was longer than the 3-5 min recommended in the guidelines, and 8% (4/53) received no adrenaline. The median interval between adrenaline doses during CPR was 6.5 min (25th-75th percentile: 5.1-10.4). Adherence to guidelines was lower in out-of-hospital cardiac arrest than in in-hospital cardiac arrest (P = 0.01).

CONCLUSIONS

In the majority of cases adrenaline did not appear to be administered according to current ACLS guidelines.

Low utilisation of unactivated protein C in a patient with meningococcal septic shock and disseminated intravascular coagulation

BACKGROUND

Activated protein C has recently been shown in a multicentre trial to significantly reduce mortality in patients with septic shock. There are also some case reports and minor studies demonstrating promising results with the unactivated form of protein C. However, in children with severe meningococcal infection, skin biopsies have demonstrated low expression of endothelial thrombomodulin and protein C receptors, suggesting low protein C activation capacity in severe meningococcal sepsis.

METHODS

A patient with meningococcal septic shock was treated with two doses of the unactivated form of protein C, the first during intense activation of the coagulation system and the second during a phase of low grade or no activation. Repeated plasma samples were analysed for protein C concentration, which made it possible to compare pharmacokinetics and half-lives of the two administrations. A shorter half-life during intense coagulation was expected if there was an activation and consumption of the protein C administered.

RESULTS

The calculated half-lives of protein C during intense and low grade activation were 32 h and 19 h, respectively, a magnitude similar to that reported in protein C-deficient patients without infection.

CONCLUSION

The result indicates that whole body utilisation of the unactivated protein C was low. Endothelial impairment of protein C activation does not seem to be restricted to the skin vessels only.

Cerebral ischaemia in experimental cardiopulmonary resuscitation--comparison of epinephrine and aortic occlusion

The apparent inability of epinephrine to improve outcome after cardiopulmonary resuscitation (CPR) could be caused by direct negative effects on the cerebral circulation. Constant aortic occlusion with a balloon catheter could be an alternative way to improve coronary and cerebral perfusion during CPR. The objective of the present study was to compare the effects of standard-dose epinephrine with balloon occlusion of the descending aorta on cortical cerebral blood flow augmentation during CPR. Ventricular fibrillation was induced in 24 anaesthetised piglets. A non-intervention interval of 9 min was followed by open-chest CPR. The animals were randomised to receive repeated intravenous bolus doses of epinephrine 20 microg/kg or balloon occlusion of the descending aorta. Focal cortical cerebral blood flow was measured continuously using laser-Doppler flowmetry. Balloon occlusion of the aorta resulted in a significantly higher mean cortical cerebral blood flow and a lower cerebral oxygen extraction ratio than epinephrine during CPR. After restoration of spontaneous circulation the cerebral perfusion appeared compromised to the same extent in both groups, with lower blood flow compared to baseline, high cerebral oxygen extraction and cerebral tissue acidosis. No difference in cerebral cortical vascular resistance between the two groups could be detected. It is concluded that aortic balloon occlusion was superior to epinephrine in cerebral blood flow augmentation during resuscitation and did not generate adverse effects on cerebral blood flow, oxygenation or tissue pH after restoration of spontaneous circulation. No evidence of cerebral vasoconstriction induced by standard-dose epinephrine was found.

Adverse effects of high-dose epinephrine on cerebral blood flow during experimental cardiopulmonary resuscitation

OBJECTIVE

To study the effects of high-dose epinephrine, compared with standard-dose epinephrine, on the dynamics of superficial cortical cerebral blood flow as well as global cerebral oxygenation during experimental cardiopulmonary resuscitation. We hypothesized that high-dose epinephrine might be unable to improve cerebral blood flow during cardiopulmonary resuscitation as compared with standard-dose epinephrine.

DESIGN

Randomized controlled study.

SETTING

University hospital research laboratory.

SUBJECTS

A total of 20 male anesthetized piglets.

INTERVENTIONS

Ventricular fibrillation was induced. A nonintervention interval of 8 mins was followed by open-chest cardiopulmonary resuscitation. The animals were randomized to receive repeated bolus injections of either 20 microg/kg (standard-dose group, n = 10) or 200 microg/kg (high-dose group, n = 10) of epinephrine.

MEASUREMENTS AND MAIN RESULTS

Focal cortical cerebral blood flow was measured continuously by using laser Doppler flowmetry. The duration of blood flow increase was significantly shorter in the high-dose group after the second dose of epinephrine. In the high-dose group there was also a consistent tendency for lower peak levels and shorter duration of flow increase in response to repeated bolus doses of epinephrine. Cerebral oxygen extraction ratio was significantly lower in the high-dose group after administration of epinephrine.

CONCLUSIONS

Repeated bolus doses of epinephrine 200 microg/kg, as compared with 20 microg/kg, do not improve superficial cortical cerebral blood flow during experimental open-chest cardiopulmonary resuscitation. High-dose epinephrine appears to induce vasoconstriction of cortical cerebral blood vessels resulting in redistribution of blood flow from superficial cortex. This might be one explanation for the failure of high-dose epinephrine to improve overall outcome in clinical trials.

Improved haemodynamics and restoration of spontaneous circulation with constant aortic occlusion during experimental cardiopulmonary resuscitation

Continuous balloon occlusion of the descending aorta is an experimental method that may improve blood flow to the myocardium and the brain during cardiopulmonary resuscitation (CPR). The aim of the present investigation was to evaluate the effects of this intervention on haemodynamics and the frequency of restoration of spontaneous circulation. Ventricular fibrillation was induced in 39 anaesthetised piglets, followed by an 8-min non-intervention interval. In a haemodynamic study (n = 10), closed chest CPR was performed for 7 min before the intra-aortic balloon was inflated. This intervention increased mean arterial blood pressure by 20%, reduced cardiac output by 33%, increased coronary artery blood flow by 86%, and increased common carotid artery blood flow by 62%. All these changes were statistically significant. Administration of epinephrine further increased mean arterial blood pressure and coronary artery blood flow, while cardiac output and common carotid artery blood flow decreased. In a study of short-term survival, nine out of 13 animals (69%) in the balloon group and in three out of 13 animals (23%) in the control group had spontaneous circulation restored. The difference between these two proportions was 0.46, which was statistically significant with a 95% confidence interval from 0.12 to 0.80. In conclusion, balloon occlusion of the descending aorta increased coronary and common carotid artery blood flow and the frequency of restoration of spontaneous circulation. It was also noted that epinephrine appears to augment the redistribution of blood flow caused by the aortic occlusion.

Maximisation of cerebral blood flow during experimental cardiopulmonary resuscitation does not ameliorate post-resuscitation hypoperfusion

Continuous intra-aortic balloon occlusion has been reported to improve cerebral blood flow during cardiopulmonary resuscitation (CPR) but not to ameliorate the impaired blood recirculation occurring after restoration of spontaneous circulation (ROSC). Volume expansion with hypertonic solutions may improve recovery of brain function by enhancing post-resuscitation cerebral blood flow. We hypothesised that the combination of these treatments with open-chest CPR would improve cerebral blood flow during CPR, and attenuate post-resuscitation flow disturbances. In 32 anaesthetised piglets, catheters were placed for haemodynamic and blood gas monitoring. Open-chest CPR was initiated after 9 min of ventricular fibrillation. The piglets were treated either with 3 ml kg(-1) hypertonic saline and dextran (HSD) (n = 10), HSD and balloon occlusion (n = 10) or with normal saline (n = 12). After 7 min of CPR, internal defibrillatory shocks were administered to restore spontaneous circulation. Haemodynamic variables, continuous cerebral cortical blood flow, cerebral tissue pH and pCO2 and blood gas parameters were measured during CPR and up to 210 min after ROSC. Higher cerebral perfusion pressure was found in the balloon-HSD group during CPR. This group exhibited less arterial hypertension immediately after ROSC compared with the other groups. Thereafter, a fairly rapid decrease of the perfusion pressures was observed in all groups reaching a minimum level approximately 30 min after ROSC. Cerebral cortical blood flow was significantly higher and cerebral oxygen extraction ratio significantly lower in the balloon-HSD group during CPR, but not after ROSC. In conclusion, a combination of intra-aortic balloon occlusion and HSD administration improves cerebral blood flow and brain oxygen supply during experimental open-chest CPR. In contrast, cerebral blood flow after ROSC was not shown to be influenced by this treatment.

Experimental model of cardiovascular post-resuscitation syndrome--no effect of platelet activating factor antagonism

The cardiovascular instability seen in the reperfusion phase after resuscitation from cardiac arrest may contribute to secondary brain injury. The aim of the present study was to characterise post-resuscitation cardiovascular instability in an experimental model of cardiac arrest and to test if cardiovascular stability could be improved by pre-treatment with the platelet activating factor (PAF) antagonist BN52021. Ten anaesthetised pigs received pre-treatment with BN52021 before induction of ventricular fibrillation (arrest/BN52021 group), while ten animals received only the vehicle (arrest/vehicle group). After a non-intervention interval of 9 min, resuscitation was attempted. Resuscitated animals were observed for 5 h and compared to a sham arrest group of seven animals. The haemodynamic situation after resuscitation was characterised by a low cardiac output that was inadequate in relation to the oxygen demand, as reflected by a low mixed venous oxygen saturation. The arterial blood pressure was to some extent reduced and the filling pressures in both the right and left heart were increased, but urinary output was not reduced. The severe haemodynamic compromise was not adequately reflected by standard monitoring variables such as arterial blood pressure and urinary output. Pre-treatment with BN52021 was unable to improve any aspect of short-term survival or haemodynamic stability.

The biological activity of adrenaline after injection through an intravenous cannula containing alkaline buffer

Since it is known that alkaline pH inactivates adrenaline it has been recommended that this drug not be administered in the same i.v. line as alkaline buffer solutions during cardiopulmonary resuscitation. In order to test the validity of this statement a simulation model of the clinical situation was designed where the biological activity of adrenaline was measured in anesthetized rats after having been mixed with alkaline buffer solution contained in a standard i.v. cannula. The biological activity of adrenaline was measured by comparing the blood pressure response after repeated administration of a test (adrenaline + alkaline buffer) and control (adrenaline + normal saline) solution to a rat which had previously received a ganglion-blocking agent. Two alkaline buffer solutions, sodium bicarbonate and Tris buffer mixture were tested. These resulted in a decrease of the biological effect of adrenaline to 77 +/- 6 and 82 +/- 9% of control values, respectively. If however, adrenaline mixed with Tris buffer mixture was injected into a recipient of phosphate buffer (pH 7.40 and buffer capacity equal to human blood) as much as 94 +/- 17% of its activity remained. The results lead us to suggest that, in the cardiopulmonary resuscitation situation, adrenaline may well be given via a cannula containing alkaline buffer solution without significant interference with its effect.