[Retrospective analysis of the work of a medical education office]

BACKGROUND

Training of health care students at universities is a great challenge for Medical Education Offices. Our office made clear and explained the teaching-learning process from the perspective of teachers, programs, and students.

AIM

To report a ten years' analysis of a Medical Education Office (MEO) work, describing the different processes and systematized decisions aimed to improve the quality of the programs and learning results.

MATERIAL AND METHODS

A 10 years retrospective analysis of the Medical Education Office processes directed to Medicine, Nursing, Physical Therapy, and Nutrition careers of a Faculty of Medicine. Flunks between 2013 and 2017 were compared.

RESULTS

A progressive reduction in flunks was observed in the four careers. Specifically, the proportion of flunks in Nutrition decreased from 30 to 9%. When comparing flunks using a Chi-square test of homogeneity in the four careers, a significant decrease in four of six courses was observed. This led to a sustained increase in number of students who completed their career and obtained their title. Specifically, in Medicine there was a 7.5-fold increase in these figures. The Diploma course trained 90% of the teachers in charge of courses of the four careers. The master's degree generated research that allowed to increase the productivity in health sciences education.

CONCLUSIONS

The Office of Medical Education created knowledge and management models for the education of health sciences students, enhancing the quality of training and learning processes.

[Evaluation of a teaching training program implemented in a faculty of medicine]

BACKGROUND

Since 2010, the Faculty of Medicine at Finis Terrae University implemented a training program aiming to train health professionals in effective educational practices.

AIM

To evaluate the effect of training in teachers who are in charge of planning courses, conducting classes and learning assessment.

MATERIAL AND METHODS

Quality of planning, lecture performance and academic performance of students were evaluated in 55 teachers prior and after attending the training course on teaching methodologies and in 47 teachers not attending the course.

RESULTS

The percentage of trained teachers complying with the aforementioned indicators was significantly higher than those without training (p < 0.01). There were significant differences in favor of the group of teachers who attended and passed the Diploma. Trained teachers had significantly higher students' approval rate. (Odds ratio 4.5, p < 0.01).

CONCLUSIONS

The teaching Diploma in Health Sciences improved the planning, teaching and academic performance of teachers.

[The efficiency of self-regulated learning in the teaching of scientific concepts to health sciences students]

BACKGROUND

In health sciences, the predominant teaching methodology is traditional and emphasizes conveying knowledge. Nonetheless, new abilities must be taught now. This change shifts the prominence from professor to student and incorporates a concept called self-regulated learning, which involves the professor as a mediator and incorporates guidelines that facilitate learning diverse skills.

AIM

To compare the effects of two teaching methodologies on the learning of key scientific concepts among health science students.

MATERIAL AND METHODS

Two subgroups of equally complex concepts were randomly chosen to be taught either using traditional or self-regulation methodology. For the self-regulation methodology, two groups were formed. One learned only through self-regulation guidelines and the other learned through classes where the professor was a mediator. One hundred thirty seven freshman students from medicine, physical therapy, and nursing careers participated voluntarily in the study.

RESULTS

Self-regulation methodology impacted the learning process of scientific concepts in a positive way and showed significant differences with traditional teaching. The sole use of self-regulation guidelines alone generated similar results, compared to those obtained by students who attended lectures.

CONCLUSIONS

Self-regulated learning would improve in learning efficiency and would reduce face-to-face class time.

[Effects on academic performance of a leveling program in basic sciences in first year medical students]

BACKGROUND

A significant number of students in health careers do not have the knowledge to approve basic courses. Therefore, educational programs to level off knowledge have been developed.

AIM

To associate the results of a leveling program with the academic performance in cell biology (CB) and biochemistry (BC) of first year medical students.

MATERIAL AND METHODS

We applied a test to first year medical students at the beginning and end of the leveling program (control test). The results obtained at the end of the leveling program were correlated with the results obtained in CB and BC.

RESULTS

Fifty seven of 89 (64%) first year medical students met the study entry criteria (54% female). Students who completed the leveling program had a significantly higher approval rate in CB (93% versus 75%, P = 0.024), and in BC (95% versus 69%, P = 0.001). After completing the leveling program, the risk of failing CB and BC, decreased by 72 and 84% respectively.

CONCLUSIONS

This study shows that medical students who participate in the leveling program decrease the chances of failing in CB and BC.

An evidence-based resuscitation algorithm applied from the emergency room to the ICU improves survival of severe septic shock

BACKGROUND

Septic shock is highly lethal. We recently implemented an algorithm (advanced resuscitation algorithm for septic shock, ARAS 1) with a global survival of 67%, but with a very high mortality (72%) in severe cases [norepinephrine (NE) requirements >0.3 microg/kg/min for mean arterial pressure > or =70 mmHg]. As new therapies with different levels of evidence were proposed [steroids, drotrecogin alpha, high-volume hemofiltration (HVHF)], we incorporated them according to severity (NE requirements; algorithm ARAS-2), and constructed a multidisciplinary team to manage these patients from the emergency room (ER) to the ICU. The aim of this study was to compare the outcome of severe septic shock patients under both protocols.

METHODS

Adult patients with severe septic shock were enrolled consecutively and managed prospectively with ARAS-1 (1999-2001), and ARAS-2 (2002-05). ARAS-2 incorporates HVHF for intractable shock.

RESULTS

Thirty-three patients were managed with each protocol, without statistical differences in baseline demographics, APACHE II (22.2 vs 23.8), SOFA (11.4 vs 12.7) and NE peak levels (0.62 vs 0.8 microg/kg/min). The 28-day mortality and epinephrine use were higher with ARAS-1 (72.7% vs 48.5%; 87.9% vs 18.2 %); and low-dose steroids (35.9% vs 72.7%), drotrecogin (0 vs 15 %) and HVHF use (3.0% vs 39.4%) were higher for ARAS-2 (P<0.05 for all).

CONCLUSION

Management of severe septic shock with a multidisciplinary team and an updated protocol (according to the best current evidence), with precise entry criteria for every intervention at different stages of severity, may improve survival in these patients. Multidisciplinary management, rationalization of the use of vasoactives and rescue therapy based on HVHF instead of epinephrine may have contributed to these

RESULTS

Management of severe septic shock with these kinds of algorithms is feasible and should be encouraged.

[Thiazide induced acute pulmonary edema: report of one case]

Acute pulmonary edema caused by thiazides is uncommon and of difficult diagnosis. It is considered an idiosyncratic reaction and the physiopathology or cardiac function changes are not well known. We report a 60 year-old female with a thiazide induced acute pulmonary edema who was followed with serial measurements of type B n-terminal natriuretic peptide fraction as marker for cardiac dysfunction. There was a significant elevation of the peptide, not associated to evidences of ventricular dysfunction. Its normalization paralleled the resolution of the clinical picture.

Los predictores de satisfacción de pacientes en un centro hospitalario universitario

BACKGROUND

Client satisfaction is an important indicator of the quality of services, and health care is not an exemption.

AIM

To explore and establish the predictors that exert the greater influence on the level of satisfaction with the service offered in a University Hospital.

MATERIAL AND METHOD

The source of the study is a data base, obtained from a survery made to 355 patients of the Hospital Clínico de la Pontificia Universidad Católica de Chile prior to discharge. A multiple regression analysis was used to determine the relative importance of the different factors in the quality of service. The regression variables were reduced to a number of factors, obtained of Factorial Analysis and a Varimax rotation, allowing them to clarify their relations.

RESULTS

After performing the main components analysis, seven factors or dimensions that explained a 69% of the total variance were obtained. The predictive model explains up to 40% of the criterion variable (Global Satisfaction during the hospitalization). The factor with the greatest predictive power was the relationship between the patients and nursing staff. Other factors that emerged as important were communication, medical attention and room conditions.

CONCLUSIONS

Perceptive type components had the greater relative weight to determine the level of patient satisfaction in this survey.

High-volume hemofiltration as salvage therapy in severe hyperdynamic septic shock

OBJECTIVES

To evaluate the effect of short-term (12-h) high-volume hemofiltration (HVHF) in reversing progressive refractory hypotension and hypoperfusion in patients with severe hyperdynamic septic shock. To evaluate feasibility and tolerance and to compare observed vs. expected hospital mortality.

DESIGN AND SETTING

Prospective, interventional, nonrandomized study in the surgical-medical intensive care unit of an academic tertiary center.

PATIENTS

Twenty patients with severe septic shock, previously unresponsive to a multi-intervention approach within a goal-directed, norepinephrine-based algorithm, with increasing norepinephrine (NE) requirements (>0.3 microg kg(-1) min(-1)) and lactic acidosis.

INTERVENTIONS

Single session of 12-h HVHF.

MEASUREMENTS AND RESULTS

We measured changes in NE requirements and perfusion parameters every 4h during HVHF and 6h thereafter. Eleven patients showed decreased NE requirements and lactate levels (responders). Nine patients did not fulfill these criteria (nonresponders). The NE dose, lactate levels, and heart rates decreased and arterial pH increased significantly in responders. Hospital mortality (40%) was significantly lower than predicted (60%): 67% (6/9) in nonresponders vs. 18% (2/11) in responders. Of 12 survivors 7 required only a single 12-h HVHF session. On logistic regression analysis the only statistically significant predictor of survival was theresponse to HVHF (odds ratio 9).

CONCLUSIONS

A single session of HVHF as salvage therapy in the setting of a goal-directed hemodynamic management algorithm may be beneficial in severe refractory hyperdynamic septic-shock patients. This approach may improve hemodynamics and perfusion parameters, acid-base status, and ultimately hospital survival. Moreover, it is feasible, and safe.

[Comparison of cardiac output measurement in critical patients using transesophageal Doppler or thermodilution: a preliminary report]

BACKGROUND

Cardiac output can be measured non invasively by transesophageal Doppler. This is an alternative to measure it by thermodilution with a catheter in the pulmonary artery.

AIM

To compare both methods of cardiac output measurement.

MATERIAL AND METHODS

Simultaneous measurement of cardiac output by transesophageal Doppler and thermodilution with a catheter in the pulmonary artery in four male critical patients, aged 60+/-12 years, hospitalized in a University Hospital. The Bland and Altman method to compare the concordance between two measurements, was used.

RESULTS

Forty measurements were performed. The results of both methods had a correlation coefficient of 0.98. According to the Bland and Altman method, the difference between both methods was -0.5 L with a precision of 0.52 L/min (95% confidence interval -1.51 to 0.52 L/min). Considering that a change between two sequential measurements is considered significant when the difference is more than 15%, both measurements agreed in 83% of cases, that there was a change in cardiac output.

CONCLUSIONS

Transesophageal Doppler is a promising non invasive technique to measure cardiac output in critical care patients. It becomes a valid alternative to the thermodilution technique. This preliminary experience must be confirmed in a larger series.

Massive Pulmonary Embolism: Percutaneous Mechanical Thrombectomy during Cardiopulmonary Resuscitation

Seven patients with massive pulmonary embolism (PE) causing cardiac arrest underwent percutaneous mechanical thrombectomy (PMT) with Hydrolyser and Oasis catheters during cardiopulmonary resuscitation (CPR). Three received adjunctive recombinant tissue plasminogen activator. Thrombectomy was successful in restoring pulmonary perfusion in six patients (85.7%). One patient died of cardiac arrest. Systolic pulmonary pressure decreased after thrombectomy from a median of 73 mm Hg (range, 63-90 mm Hg) to 42 mm Hg (range, 32-81 mm Hg; P < .05). There was one groin hematoma that required blood transfusion. In conclusion, massive PE causing cardiac arrest can be treated with PMT simultaneously with CPR maneuvers to rapidly revert circulatory collapse, with restoration of pulmonary circulation. Larger series are needed to validate this method.

[Hantavirus cardiopulmonary syndrome: utility of the PICCO(Pulse contour cardiac output) system for monitoring]

We report a 68 years old man, farmer from the metropolitan region, admitted with a Hantavirus Cardiopulmonary Syndrome. The diagnosis was made using serologic test and was later confirmed by the Public Health Institute. He evolved to an early multiple organ failure, requiring high concentrations of oxygen and invasive ventilatory assistance, vasopressor drugs and renal replacement therapy. Swan Ganz and PiCCO were used simultaneously for hemodynamic monitoring. Treatment consisted in global support therapy, antimicrobial therapy and systemic corticosteroids. Intrathoracic blood volume was a more reliable parameter than pulmonary capillary wedge pressure for the assessment of preload. As expected in situations of increased vascular permeability, there was an increase in extravascular lung water. There was a good correlation between extravascular lung water and oxygenation parameters (PaO2/FiO2 and oxygenation index). PiCCO system may become a helpful tool in the management of patients with Hantavirus Cardiopulmonary Syndrome.

[Vibrio vulnificus: an infrequent cause of septic shock]

Vibrio vulnificus is a lactose positive Gram negative rod that lives in warm seas and can infect wounds and produce sepsis. Its infection is acquired after eating oysters or other filtering marine organisms. We report a 53 years old diabetic male who started with fever after a voyage to Central America. He was admitted febrile, hypotense, dehydrated and polypneic. Painful erythematous lesions and lumps were observed in his upper and lower limbs. After 72 hours of evolution, the lesions became violaceous, with crepitating vesicles full of hemorrhagic exudate. He developed a renal failure and a disseminated intravascular coagulation. Blood cultures demonstrated the presence of Vibrio vulnificus and the patient died 68 hours after admission.

[Study of cytokines kinetics in severe sepsis and its relationship with mortality and score of organic dysfunction]

BACKGROUND

The Infectious Systemic Inflammatory Response syndrome and multiple organic dysfunction have common physiopathological mechanisms. Multiple organic dysfunction can be assessed using severity scores.

AIM

To relate cytokine kinetics with a multiple organic dysfunction score during sepsis.

MATERIAL AND METHODS

Tumor necrosis factor alpha (TNF alpha) and interleukin 6 (IL6) kinetics were studied in 25 patients with severe sepsis with less than 48 h of evolution and interleukin 1 beta (IL beta) kinetics was studied in 13 patients. Measurements were made at 0, 12, 24 and 48 hours after admission to the study, using an ELISA technique. These parameters were correlated with the Marshall multiple organic dysfunction score and survival.

RESULTS

Mean age of study subjects was 70 years, the APACHE II score was 16.9 +/- 6 and the Marshall score was 6.8 +/- 3.6. Sepsis was of pulmonary origin in 56% of patients and intra abdominal in 32%. Mortality was 36%. TNF alpha increased during the study period (24.1 pg/ml initially and 37.8 pg/ml at 24 hours, with a slight posterior reduction, p < 0.02). These levels had no association with mortality or organic dysfunction. IL6 remained elevated during the first hours and had a tendency to decrease thereafter. Decreased patients had higher values than survivors (306 pg/ml and 55.4 pg/ml respectively, p = 0.011). Its values were tightly correlated with Marshall score, with the number of failing organs, with the presence of shock and with probability of dying during hospitalization. IL1 beta remained low and was not associated with clinical parameters.

CONCLUSIONS

There is a tight correlation between the elevation of IL6 and the severity of the Systemic Inflammatory Response and mortality in these patients with sepsis.

[Systemic inflammatory response syndrome: is it comparable with severe sepsis?]

BACKGROUND

In 1992, a consensus conference defined the terms systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis and septic shock. Since then, numerous reports have validated the prognostic usefulness of these operative definitions.

AIM

To evaluate if sepsis severity criteria, as defined by the Consensus Conference, can be applied to noninfectious SIRS.

PATIENTS AND METHODS

Five hundred eighteen patients admitted to 5 intensive care units (ICU) from 4 hospitals were prospectively evaluated during a 3 months period. Patients that met at least one severity criteria were included. SIRS etiology, organ dysfunction and evolution were recorded in each patient.

RESULTS

One hundred two patients were included: 79 with sepsis (group I) and 23 with noninfectious SIRS (group II). ICU and hospital mortality were comparable (43 and 48% in sepsis compared to 43 and 51% in non infectious SIRS). The most common sources of sepsis were pneumonia and peritonitis. Group II patients had a wide variety of diseases. ICU stay, APACHE score and number of organs with dysfunction were not different among groups. Only the incidence of renal dysfunction was higher in the septic group.

CONCLUSIONS

The Consensus sepsis severity criteria can be applied to noninfectious SIRS, defining a population subset with similar high mortality and organ dysfunction incidence, although with greatly heterogeneous etiologies.

Use of methylene blue in patients with refractory septic shock: impact on hemodynamics and gas exchange

PURPOSE

The purpose of this study was to assess the acute effects of methylene blue, an inhibitor of nitric oxide synthesis, on hemodynamics and gas exchange in patients with refractory septic shock in a prospective clinical trial at medical and surgical intensive care units in a tertiary university hospital.

PATIENTS AND METHODS

Prospective, sequential study of 10 consecutive patients admitted with severe septic shock of diverse causes and unable to achieve an adequate arterial pressure despite the use of at least two vasoactive drugs. Six of them also developed acute lung injury. All received 1 mg/kg intravenous bolus of methylene blue. Hemodynamic and respiratory parameters were measured at baseline and at 30, 60, 120, and 180 minutes after the bolus injection.

RESULTS

Systolic, diastolic, mean arterial blood pressure, and systemic vascular resistance increased significantly in all patients, whereas no significant changes were observed in cardiac output, oxygen consumption, or oxygen extraction ratio. Gas exchange remained unaffected in patients with acute lung injury.

CONCLUSIONS

Methylene blue had an acute vasopressor effect in patients with refractory septic shock, and it was not deleterious on respiratory function.

[Study of the survival of elderly patients in intensive care units. Should they be admitted to these units?]

BACKGROUND

An important increase in health care costs has occurred lately, determined in part by the expenses of intensive care units. An important proportion of beds in these units are occupied by elders, with high costs and dubious results.

AIM

To study the survival of elderly patients in intensive care units to shed light on the question if these patients should be admitted to these facilities.

MATERIAL AND METHODS

We retrospectively analyzed the mortality of 443 patients older than 65 years old, admitted to an intensive care unit between 1993 and 1994. The mortality was compared with that of 334 younger patients admitted in the same period. Severity of disease was determined using admission APACHE II score.

RESULTS

Older patients had a higher admission APACHE score than younger subjects (18.4 +/- 8.4 and 14.5 +/- 8.7 respectively, p < 0.01). Mortality during the intensive care unit stay was similar in older and younger patients (18.5 and 14.4%, respectively). Hospital mortality was also similar (22.4 and 25.9%, respectively). Older patients had a higher frequency of chronic diseases and degree of functional impairment. Mortality rates for different diseases were also similar in older and younger patients.

CONCLUSIONS

Older age was not associated with a higher mortality during intensive care unit stay. Prognosis is determined by the admission severity score and the number of concomitant chronic diseases.

[Clinical epidemiologic study of patients admitted to the intensive care unit, according to age]

BACKGROUND

Lately, we have observed an increase in the admission to intensive care units of patients over 65 years old, probably due to the increase in life expectancy that is occurring in Chile.

AIM

To compare the frequency of admissions to intensive care units in patients over 65 years old, their diagnoses, their severity and hospital course, with those of younger patients.

PATIENTS AND METHODS

The charts of all patients admitted to an intensive care unit of a University Hospital, during one year, were reviewed. The diagnosis that caused the admission was considered the main disease. Severity at the moment of admission was assessed using the Apache score.

RESULTS

A total of 777 patients were admitted during the study period. Twenty had to be excluded due to lack of reliable data. Four hundred thirty two (57%) were over 65 years old. Cardiovascular diseases were the main cause of admission in young and old patients. Mortality was 14.8% of patients over 65 years old and 18.7% in younger patients. Main causes of death were cardiac arrest, cardiogenic shock, sepsis and cerebrovascular disease. No differences in causes of death were observed between young and old patients.

CONCLUSIONS

Patients older than 65 years old admitted to intensive care units are very similar to their younger counterparts in their prognosis and causes of admission.

[Malignant neuroleptic syndrome, medical-psychiatric approach]

We report the case of a 42 years old male, with a bipolar disorder and receiving lithium therapy, valproic acid and clonazepam. Due to an exacerbation of his underlying disease, he was admitted to a psychiatric clinic and received 50 mg of intramuscular chlorpromazine in two occasions. Afterwards, the patient had an alteration of consciousness, fever reaching 39 degrees C and generalized muscular rigidity. Laboratory work-up showed a normal brain CT scan, a diffuse slowness in the EEG and a creatinphosphokinase that reached values of 3.040 U/l. He was transferred to an intensive care unit and treated with sodium dantrolene and bromocriptine, obtaining a good clinical response.

[Patients with acute adult respiratory distress syndrome: effects of inhaled nitric oxide on gas exchange and hemodynamics]

BACKGROUND

Adult respiratory distress syndrome is highly prevalent in intensive care units and has a high mortality. Lately, nitric oxide has been used as adjuvant therapy.

AIM

To study the effects of nitric oxide inhalation in patients with adult respiratory distress syndrome.

PATIENTS AND METHODS

Twelve patients with adult respiratory distress syndrome, were subjected to nitric oxide inhalation at a concentration of 10 parts per million, during 30 minutes.

RESULTS

At the end of the nitric oxide inhalation period, there was an improvement of PaO2/FIO2 ratio from 89 +/- 32 to 111 +/- 43 mm Hg and a 16% reduction of lung shunting (Qs/Qt).

CONCLUSIONS

Nitric oxide inhalation at a concentration of 10 parts per million improved arterial oxygenation and reduced pulmonary shunting in patients with adult respiratory distress syndrome.

[Inhibition of the nitric oxide pathway in refractory septic shock]

AIM

To assess the acute effects of methylene blue infusion, an inhibitor of nitric oxide synthesis, on hemodynamic parameters in patients with refractory septic shock.

PATIENTS AND METHODS

Fourteen patients admitted to intensive care units with septic shock of diverse etiologies and unable to maintain median arterial pressures over 60 mm Hg with the use of at least 2 vasoactive drugs, were studied. All received a 1 mg/kg bolus of methylene blue Hemodynamic parameters were measured before and 30, 60, 120 and 180 min after the bolus.

RESULTS

Systolic and diastolic blood pressure and systemic vascular resistance increased in all patients. There were no significant changes in cardiac output, oxygen consumption or extraction.

CONCLUSIONS

Methylene blue has an acute pressor effect in patients with septic shock.

[Prolonged inhalation of nitric oxide in adult respiratory distress syndrome in a case]

Inhalation therapy with nitric oxide has been suggested as beneficial in the adult respiratory distress syndrome, however there are few reports of its prolonged use. We report a patient with a chronic lymphocytic leukemia that developed an adult respiratory distress syndrome with severe hypoxemia, refractory to conventional therapeutic measures, during the course of a septic shock. The patient received nitric oxide (19 ppm) improving arterial oxygen saturation and allowing the reduction of FiO2 to 40%. The patient died five days later due to a multiple organ failure.

[Vital prognosis in severe acute hepatic failure. Value of the quantitative indexes of evaluation]

The aim of this study was to assess the predictive value for mortality of admission and daily APACHE II score, mortality due to multiple organ failure and the Organ Failure Score in patients with acute hepatic failure. We retrospectively studied 15 such patients admitted to an intensive care unit. Thirteen patients died (87%) and their admission APACHE II score was 22 +/- 7.5 compared to 21 +/- 8.5 in survivors. Daily APACHE II score, mortality due to multiple organ failure and multiple organ failure score had a 100% sensitivity to predict mortality and a 69.2, 76.9 and 76.9% specificity respectively. The predictive accuracies of multiple organ failure and multiple organ failure score were 80% and significantly better than the accuracy of admission APACHE II score (53%). We conclude that these prognostic scores can be useful in the assessment of patients with acute hepatic failure.

[Multiple organ failure syndrome in fulminant hepatic failure]

BACKGROUND

in fulminant hepatic failure, different organs systems become involved and a multiple systems organic failure may ensure.

AIM

to perform a retrospective analysis of patients with fulminant hepatic failure admitted to UC Hospital Intensive Care Unit.

PATIENTS AND METHODS

the charts of fourteen patients (8 male) were analyzed. Multiple systems organic failure was defined as the presence of 2 or more organic dysfunctions. The evolution and mortality of these patients was analyzed.

RESULTS

patient's ages ranged from 30 to 74 years. The etiology of hepatic failure was B hepatitis in 4, non A non B hepatitis in 5, acute fatty liver of pregnancy in 3 and use of halothane and HIN in 2. ICU stay ranged from 1 to 44 days and 2 patients survived (one with drug induced liver failure and one with acute fatty live of pregnancy). Mean prothrombin time was 19 +/- 9.5%, total bilirrubin was 24 +/- 8.9 mg/dl and 12 patients reached grade IV encephalopathy. Mean admission APACHE II score was 21.5 +/- 6. Twelve patients developed multiple systems organic failure, that appeared 1.5 days after or was already present at ICU admission; it lasted a mean of 2.5 days and all these 12 patients died. Neurologic involvement occurred in 13 patients, renal in 10, cardiovascular in 9, respiratory in 5 and hematological involvement in 1.

CONCLUSIONS

multiple systems organic failure is frequent in fulminant hepatic failure and is associated with a high mortality.

Evaluation of oxygen uptake and delivery in critically ill patients: a statistical reappraisal

OBJECTIVE

The evaluation of oxygen consumption (VO2) and oxygen delivery (DO2) has gained increasing importance in the monitoring of critically ill patients. They can be obtained from either direct measurements or by indirect calculations based on the Fick principle. However the choice between these two approaches remains controversial. The aim of the study was to investigate whether these 2 methods provide similar results, and if not, to define the best one in terms of reproducibility.

DESIGN

Oxygen delivery and oxygen consumption were prospectively analyzed in 171 consecutive critically ill patients. Metabolic data were obtained simultaneously.

SETTING

The study was completed in the intensive care unit as part of the management of the patients studied.

PATIENTS

A first "group" of 279 evaluations was carried out in 73 consecutive critically ill patients. The results were subsequently validated by 423 observations performed in the 98 following patients.

INTERVENTIONS

Before and during each evaluation, the patients were kept in stable hemodynamic and metabolic conditions. All were mechanically ventilated.

MEASUREMENTS AND RESULTS

VO2 was evaluated by calculation (Fick principle) and direct measurement using indirect calorimetry. Cardiac output was both measured by the thermodilution technique and calculated (Fick principle) and the data were used for the evaluation of the directly measured and indirectly calculated DO2. For both VO2 and DO2 the agreement between direct and indirect evaluations was not satisfactory. Differences as great as 55 ml/min.m2 and 267 ml/min.m2 between simultaneously measured and calculated VO2 and DO2 respectively may be expected. Finally, the indirect calculated methods were less reproducible than the measured ones. These observations resulted mainly from the cumulative effects of the random errors in the metabolic data entering into the calculation of VO2 and DO2.

CONCLUSIONS

Our data suggested that the indirect calculation (Fick equation) and the direct measurement (indirect calorimetry, thermodilution) of both VO2 and DO2 did not provide similar results. Direct measurements are more reproducible methods and must be preferred.

Significance of pathologic oxygen supply dependency in critically ill patients: comparison between measured and calculated methods

OBJECTIVE

oxygen supply dependency at normal or high oxygen delivery rate has been increasingly proposed as a hallmark and a risk factor in critical illnesses. We hypothesized that as far as an adequate oxygen delivery is provided, oxygen consumption, when determined by indirect calorimetry, is not dependent on oxygen delivery in critically ill patients whereas calculated oxygen consumption is associated with artefactual correlation of oxygen consumption and delivery.

DESIGN

oxygen delivery, oxygen consumption and their relationship were analyzed prospectively. Metabolic data gained from both measured and calculated methods were obtained simultaneously before and after volume loading.

SETTING

the study was completed in the intensive care unit as part of the management protocol of the patients.

PATIENTS

32 consecutive patients entered the study and were divided into 3 groups according to a clinical condition known to favour oxygen supply dependency: sepsis syndrome, adult respiratory distress syndrome and acute primary liver failure.

INTERVENTION

the rise in oxygen delivery was obtained by colloid infusion (oxygen flux test) performed in hemodynamically and metabolically stable patients. All were mechanically ventilated. No change in therapy was allowed during the test.

MEASUREMENTS AND RESULTS

oxygen consumption was simultaneously evaluated by calculation (Fick Principle) and direct measurement using indirect calorimetry. Oxygen delivery was derived from the cardiac output (thermodilution) and arterial content of oxygen. Oxygen supply dependency was considered while observing an increase in oxygen delivery greater than 45 ml/min.m2. Irrespective of patient's clinical diagnosis and outcome, measured oxygen uptake remained unaltered by volume infusion whereas both oxygen delivery and calculated oxygen consumption increased significantly. Arterial lactate level > 2 mmol/l and measured oxygen extraction ratio > 25% failed to identify oxygen supply dependency when measured data were considered.

CONCLUSION

analysis of oxygen uptake, when measured by indirect calorimetry, failed to substantiate oxygen supply dependency in the vast majority of the critically ill patients irrespective of diagnosis and outcome. Mathematical coupling of shared variables accounted for the correlation between oxygen delivery and calculated oxygen consumption.

[Mortality in an intensive care unit: predictive value of APACHE II severity score versus maximum APACHE]

Patients admitted to intensive care units (ICU) experience constant changes in their general condition. Therefore, the determination of Apache score within the first 24 hours of admission may not be a reliable index of severity. The aim of this study was to measure daily Apache scores in ICU patients, and to determine if the maximum score (Maximum Apache) attained during hospitalization had a better prognostic value than that of admission. We measured daily Apache scores to 314 patients admitted to Hospital Clínico UC ICU. Mean admission score was 17.5 +/- 9.3 (range: 1-47) and mean maximum score was 18.6 +/- 9.7 (range: 1-47), p < 0.001. Mortality during ICU stay was 17.2%, and 8.6% during hospitalization after ICU discharge. Only 78.3% of patients attained their maximum apache score during the first 24 hours of admission, whereas 21.7% attained it during the rest of ICU hospitalization. Excluding subjects with less than one day of ICU stay, 33% of patients attained maximum Apache score after 24 hours of ICU admission. Statistical analysis showed that maximum Apache score was a better predictor of mortality than that of admission.

[Clinical evaluation, evolution and intensive care treatment of severe acute pancreatitis]

Severe acute pancreatitis is morphologically characterized by an intense and necrotizing inflammatory process responsible for early remote organ dysfunctions and late regional complications. Retroperitoneal necrosis has to be identified early by several biological markers and abdominal CT study. A better understanding of the pathophysiological mechanisms underlying the natural history of severe acute pancreatitis, progress in intensive care support and the emergence of new conservative or surgical strategies aimed at removing the necrotic areas and their toxic by-products have led to a dramatic reduction in early and overall mortality for the patient with this disease.

[Sublingual captopril versus nifedipine in the treatment of hypertensive crisis]

The currently accepted drug of choice for treatment of hypertensive crisis is sublingual nifedipine. We compared the effects of sublingual captopril (25 mg) to those of nifedipine (10 mg) in 54 patients with this complication who came to the emergency room. Five min after administration of captopril, blood pressure decreased from 197.5 +/- 32.7/118.3 +/- 8.2 to 156 +/- 27.2/95.8 +/- 12.9 mmHg and heart rate decreased from 87.9 +/- 15.1 to 74.7 +/- 10.9 (p < 0.05). Blood pressure in the nifedipine group decreased from 198 +/- 27.3/120 +/- 9.8 to 147.7 +/- 17.8/86 +/- 17.9 (p < 0.05), while no change was observed in heart rate. Delayed measurements showed lower diastolic pressures at 60 and 75 min and lower systolic pressure at 120 min in the nifedipine group (p < 0.054). Few and not significantly different side effects were observed with both drugs. Thus, sublingual captopril is useful for treatment of hypertensive crisis.

Syncope: etiology, prognosis, and relationship to age

Syncope is a common and particularly troublesome problem in the elderly population. In a series of 146 patients admitted for syncope to an acute care hospital in Chile during a 4-year period, 2/3 (68%) were aged 65 years and older. A specific etiology could be established in 62%, and 3/4 of these were cardiovascular in origin. Diagnosis was established entirely on history, physical examination, resting ECG, and 24-hour cardiac monitoring in most cases but in some, more sophisticated measures (i.e., echocardiography, electrophysiologic studies, blood tests, EEG) were needed, and mostly to confirm clinically suspected problems. In-hospital mortality was 2.1% and mortality at the end of the approximately 2-year follow-up period was 18.1%. Mortality was higher for persons over age 65 than for younger persons (23.9% vs 2.3%), and for persons with cardiovascular syncope than for persons with other kinds of syncope (28.3% vs 8.9%). This study confirms the particular lethality of syncope in the elderly population and outlines a relatively simple strategy with which most syncope patients can be diagnosed without resorting to expensive procedures.

[Syncope: recurrence and prognosis during 2 years]

We followed up 143 patients that had been admitted to intensive care units of a general hospital with syncope. 127 patients (89%) remained in follow up for a mean of 24 months (range 3 to 54 months). There were 70 men and 57 women and the mean age was 71.5 years. Recurrences were observed in 21 patients (17%) and were similar for patients whose syncope had a cardiovascular origin (10%), non cardiovascular origin (25%) or an undetermined cause (18%). Mortality from cardiac or vascular causes was 20% in the cardiovascular origin group, and 5 and 4.2% in the other groups, respectively (p less than 0.005). Recurrence did not influence mortality. A history of hypertension, cerebrovascular accidents and ventricular arrhythmias was associated to higher mortality risk (p less than 0.05).

[Severity evaluation system: APACHE II, SAPS. National experience in a unit of medical intensive therapy]

We evaluated 2 new prognostic indices, APACHE II and SAPS, in 533 consecutive patients admitted to a general hospital clinical care unit. Mortality was 19.5% (13.1% in the ICU). Among non-survivors 80% had a greater than = 20 APACHE II score and 77% a greater than = 13 SAPS score. Only 2% of patients with APACHE score less than 10 or SAPS less than 7 died. A good correlation with previously used indices (APACHE I and TISS) was 0.6. Utilization of these prognostic indices allows comparison of reports from different centers, evaluation of early and long term prognosis and a help in making cost-benefit decisions.

[Syncope: general characteristics and its relation to age]

We retrospectively analyzed the clinical data of 146 patients admitted to a general hospital with the diagnosis of syncope. A definite or highly likely cause was identified in 91 patients (62%). These were of cardiovascular origin in 78%: conduction defects (31), sinus node disease (9), obstructive causes (8), ventricular arrhythmia (8), ischemia (5) and miscellaneous (14). A non cardiovascular origin was present in 22% of patients: intoxication (7), hysteria (5), hypoxemia (3), vasovagal (2), gastrointestinal bleeding (2) and 2 others. The final diagnosis in patients with a known cause was established by the history and physical examination in 16, the ECG in 42, Holter 9, ECG monitoring in ICU 8 and echocardiogram 6. No difference in the distribution of causes was present between patients below or above 65 years of age. In hospital mortality was 2%.