J. F. Monsallier

Iatrogenic complications in adult intensive care units : a prospective two-center study

Objectivesa) To evaluate the frequency, types, severity, and morbidity of iatrogenic complications; b) determine associated factors that favor iatrogenic complications; and c) suggest new or more efficient protective measures that may be taken to improve patient safety. DesignProspective, observational study. SettingTwo ICUs in France. Patients and MethodsThe study included 382 patients (age ≥15 yrs; 400 consecutive admissions). Patients were monitored by two physicians in each ICU to assess all iatrogenic complications occurring during their ICU stay, with the exception of adverse effects of drugs. An iatrogenic complication was defined as an adverse event that was independent of the patients underlying disease. ResultsWe observed 316 iatrogenic complications in 124 (31%) of the 400 admissions. Of these iatrogenic complications, 107 (in 53 [13%] of the 400 admissions) complications, were major, three leading to death. Severe hypotension, respiratory distress, pneumothorax, and cardiac arrest represented 78% of the major iatrogenic complications. Fifty-nine percent of the major iatrogenic complications had clearly identified associated factors. Human errors accounted for 67% of these factors. Patients >65 yrs (adjusted odds ratio = 2.6,95% confidence interval: 1.4 to 4.9) and those patients admitted with two or more organ failures (adjusted odds ratio = 4.8, 95% confidence interval: 2.5 to 9.2) were more likely to develop major iatrogenic complications. High or excessive nursing workload also led to an creased risk of major iatrogenic complications Persistent morbidity, secondary to iat complications at the time of discharge, present in five survivors. The risk of ICU dead was about two-fold higher for the patients with major iatrogenic complications than in the re maining patients after adjusting for the Or System Failure Score and the prognosis of the disease (relative risk = 1.92, 95% confidence terval: 1.28 to 2.56). ConclusionsMajor iatrogenic complications were frequent, associated with increased bidity and mortality rates, related to high excessive nursing workload, and were often ondary to human errors. To improve pati safety in our ICUs, preventive measures sho be targeted primarily on the elderly and the most severely ill patients. Special attent should be given to improving the organization workload and training, and promoting w use of noninvasive monitoring. (Crit Care Med 1993; 21:40–51)

Right ventricular dysfunction in patients with septic shock

Using a rapid computerized thermodilution method, we examined the evolution of right ventricular performance in 23 patients with septic shock. Nine survived the episode of septic shock. The other 14 patients died of refractory circulatory shock. Significant right ventricular systolic dysfunction, defined as decreased ejection fraction (-39%) and right ventricular dilation (+38%) was observed in all patients with septic shock. However, in the survivors, increased right ventricular preload may prevent hemodynamic evidence of right ventricular pump failure by utilizing the Frank-Starling mechanism to maintain stroke volume. Conversely, in the nonsurvivors, right ventricular dysfunction was more prononced two days after the onset of septic shock, leading to a fall in stroke. In the last patients, a decrease in contractility appears to be the major factor accounting for decreased right ventricular performance, as evidenced by the marked increase in end-systolic volume (+27%) without significant change in pulmonary artery pressure, during the later stage of septic shock. The observed right ventricular pump failure then appears associated with an alteration in diastolic mechanical properties of this ventricle, as suggested by a leftward displacement of the individual pressure-volume curves.

Hemodialysis for acute renal failure in patients with hematologic malignancies

Objective.To assess the prognosis of patients with hematologic malignancies in acute renal failure who require hemodialysis. Design.Retrospective study. Setting.ICU. Patients.Forty-three consecutive patients. Methods.Prognostic analysis using both univariate and multivariate (stepwise regression) methods. Results.Fifteen (35%) patients recovered from acute renal failure and 12 (28%) were discharged from the ICU. The prognosis of patients with acute renal failure linked to sepsis is poorer than the prognosis of the patients with acute renal failure from other etiologies. Only one patient survived in the former group (n = 26) and 11 in the latter group (n = 17); p < .0001 in multivariate analysis. When accompanied by associated respiratory failure, mortality rate was higher (93% vs. 33%; p < .0001). The Simplified Acute Physiology Score (SAPS) calculated within the first 24 hr of admission was significantly (p < .001) related to mortality when the SAPS was >13. The presence of neutropenia and the type of hematologic malignancy were not related to a worse prognosis. Tolerance to hemodialysis appeared good, and complications were rare. (Crit Care Med 1991; 19:346)

Right ventricular performance in patients with acute respiratory failure

To examine the right ventricular response to acute respiratory failure, serial studies of biventricular performance were analysed in 34 such patients, specifically detailing the role of associated underlying disease. During the initial study, the 34 patients with acute respiratory failure had a higher right ventricular end-diastolic volume than the control group (+21%), associated with a decrease in right ventricular ejection fraction, abnormalities which tended to return to normal values in the 15 survivors. In the 9 patients who died of refractory hypoxemia with severe pulmonary hypertension, the right ventricular dilation allowed to maintain stroke volume. In contrast, in 8 patients who died of septic shock, biventricular function was progressively altered (right and left ventricular ejection fraction= -37% and -35%). In 4 patients who died of cardiogenic shock (viral myocarditis), the cardiac function was the lowest (right and left ventricular ejection fraction= -59% and -60%). Only patients with acute respiratory failure associated with septic shock or viral myocarditis are unable to maintain their stroke volume.

Role of tricuspid regurgitation and left ventricular damage in the treatment of right ventricular infarction-induced low cardiac output syndrome

To evaluate, in right ventricular (RV) myocardial infarction, the role of tricuspid regurgitation (TR) and left ventricular (LV) damage and the response to treatment of low cardiac output, 20 patients were prospectively studied. Volume infusion increased cardiac output only slightly (11%, p less than 0.001), despite a dramatic increase in ventricular filling pressures. Dobutamine (4 micrograms.kg-1.min-1) markedly increased cardiac output (24%, p less than 0.001) with a decrease in ventricular filling pressures. In the 5 patients with TR, dobutamine only modestly increased cardiac output (9 vs 26%, p less than 0.001), while stroke index and LV end-diastolic dimensions decreased in comparison (-5 vs 33% and -6 vs 9%, respectively, p less than 0.001). In the absence of TR (n = 15), there was no significant difference in response to volume expansion between patients with normal (n = 7) and depressed LV ejection fraction (n = 8). In contrast, dobutamine, in patients with depressed LV function, induced a greater increase in cardiac output (38 vs 17%, p less than 0.01) and RV ejection fraction (36 vs 12%, p less than 0.05). All patients with RV infarction-induced low cardiac output responded only modestly to volume loading. Dobutamine is particularly efficacious in patients without TR who have depressed LV function by improving RV function and, consequently, LV preload. In the 5 patients with TR, increasing RV contractility failed to improve the forward stroke volume by increasing the regurgitant fraction.

Improvement of Right Ventricular Performance by Continuous Positive Airway Pressure in Adult Respiratory Distress Syndrome

Abstract Continuous positive airway pressure (CPAP) appears to improve arterial oxygenation in patients with ARDS more than mechanical ventilation at the same level of PEEP due to a less detrimental effect on cardiac output. To determine the mechanisms responsible, we studied the changes in right and left ventricular performance induced by CPAP in seven such young patients who were able to maintain spontaneous ventilation. We measured cardiac output by thermodilution and biventricular ejection fraction by equilibrium gated blood-pool scintigraphy. Biventricular end-diastolic volumes were then calculated by dividing stroke volume by ejection fraction. During CPAP breathing, cardiac output fell about 9% due to a 9% fall in heart rate as oxygen consumption fell to the same extent (11%). The stroke volume remained unchanged with a decrease in both right ventricular end-systolic (−22%) and end-diastolic (−16%) volumes. Volume expansion to normalize cardiac output during CPAP restored right ventricular preload, while end-systolic volume remained decreased. This persistent decrease in end-systolic volume with CPAP associated with a fall in right ventricular end-systolic transmural pressure suggests that right ventricular afterload decreased with CPAP. In patients with ARDS treated with CPAP, we conclude that the stroke volume does not change because of a decrease in right ventricular afterload and even increases after normalizing right ventricular preload by volume expansion.