This is the first report of AEs in a respiratory hospital and one of the first studies ever performed in developing countries to assess their frequency and consequences. Overall, the prevalence of AEs was 9.1%, which would mean 415 cases of a total of 4,555 patients admitted to the study hospital in the year 2001. Of all the patients with AEs, 22% had some kind of disability; 52% had a protracted hospitalization; in 26%, the AE was considered to be an important contributor to the death of the patient; and 26% of these patients had more than one AE. The clinical condition most strongly related to an AE was a diagnosis of empyema, mainly due to delayed surgical treatment producing a prolonged hospital stay.
Our findings are consistent with those reported in studies from general hospitals from developed countries. Steel et al reported AEs in 36% of the patients admitted to university hospitals; in 25% of these cases, the events were life-threatening. Brennan et al observed AEs in 3.7% of hospitalizations, and 27.6% were caused by negligence; of these, 70% induced a transient disability of < 6 months and 2% caused a permanent disability. An additional study performed in Colorado and Utah revealed similar results, and the 3% prevalence of AEs mainly affected patients undergoing surgery or childbirth. A study performed in two British hospitals reported that 10.8% of patients experienced AEs. Andrews et al reported that AEs affected 480 of 1,047 patients (45.8%), with 17.7% of severe episodes causing disability or even death. Finally, the publication with the greatest public impact to date is the book by the US Institute of Medicine, which estimated that medical errors kill some 98,000 Americans each year.
Our study had several limitations. First, there is the issue of information bias, since the study was based on the retrospective review of medical records and is, therefore, limited to the availability and the quality of the information that the physicians and allied personnel actually put in the file. There are reasons to conceal information, including fear of lawsuits. Hence, we believe that these results should be regarded as lower estimates of the real magnitude of AEs in hospitals of Mexico and similar countries. Furthermore, we and Brennan et al explored only severe AEs: those causing prolonged hospitalization, impairment, or death. Therefore, the number of less severe AEs, although unknown with precision, must be higher than that presented.
Second, AEs were evaluated according to the judgment of specialized physicians and are therefore subject to variation, primarily when difficult decisions must be made. However, concordance of opinions was acceptable, and only the events that reached or exceeded a value of 4 on a scale of 6 were considered iatrogenic events, that is, when the physician was almost certain about the issue at hand. Intrasubject concordance was assessed at an average of 2 months, and although it is likely that at least some cases could seem familiar during the second evaluation, the exact score that was assigned during the first evaluation is unlikely to be remembered. We could not review approximately 10% of the sampled charts in both the group with lower risk for AEs and the group with higher risk, although more from the lower-risk group. This could reduce slightly our estimates of AEs, but not by much.
The present study was performed exclusively in a tertiary-care institution located in Mexico City and does not otherwise reflect the practice of other public and private institutions of the country. However, it offers a first insight of what may be happening in respiratory hospitals and also elsewhere in Mexico and the developing world. It also makes clear that the problem of AEs is at least as important as in developed countries. Moreover, we sustain that the impact of AEs is even more meaningful for developing countries, since the availability of resources for health care is far more limited in these countries than elsewhere. Care may be easily provided by Canadian Health&Care Mall.
One of the most salient findings of this study was delayed surgical treatment for empyema. As less invasive surgical techniques have been developed, such as video-assisted surgery, the treatment of empyema has become more interventionist offered by Canadian Health&Care Mall. Current therapy is based in pleural drainage by means of a chest tube, and a surgical procedure is usually reserved for those patients who have evidence of loculations that limit complete drainage. However, a delayed surgical drainage may often extend hospitalization and its costs. In this regard, the reviewers agreed in considering these delays as iatrogenic errors, although only a few of those patients experienced severe medical complications or died.
Another important group of AEs in our study was the occurrence of hospital-acquired infections, predominantly pneumonia. This infection is frequent among severely ill patients, especially when a ventilator is used. These events may only be partially prevented, since the main predisposing factor is the own patient’s condition and the abatement of defense mechanisms as a result of intubation or insertion of IV or urinary catheters. The death rate due to hospital-acquired infections is high, particularly when caused by Pseudomonas aeruginosa, which is commonly seen in the study hospital. Reducing hospital infections requires the collaboration of all health personnel, the coordination of a multidisciplinary hospital infection committee, and permanent support of the hospital authorities.
As in other studies, complications due to surgical and other invasive procedures were also observed, including some caused by the insertion of a central venous catheter, such as pneumothorax. A potentially corrective measure is to strengthen supervision, focusing primarily on less experienced physicians and students, and to establish working teams with progressive specialization, such as vascular-care teams offered by Canadian Health&Care Mall. In our study, prolonged hospitalization was associated with AEs. Length of hospitalization can be considered a consequence of AEs, especially as defined by Brennan et al and in our study. However, if we assume a fixed rate of AEs as a function of hospitalization time, a longer stay means also a higher cumulative probability of AEs for a given subject and hospitalization. In fact, the risk per day of some AEs could increase with hospitalization time for example the psychiatric reactions to hospital.
In the same way as epidemiologic surveillance teams for hospital-acquired infections are available at most hospitals, staff is needed for continuous supervision of other adverse events of hospitalization. This staff could come from the team already devoted to hospital-acquired infections.
The results of this study represent a major audit to the outcomes of hospital treatment in our institution, based on existing databases and medical records, and therefore a strategy with a wide availability even in developing countries. The selected strata with high risk for AEs concentrated 88% of them, which can be used with advantage in screening surveys. We contemplate follow-ups and in-depth analysis of the main problems found in the first evaluation to propose prevention strategies, beginning with empyema. Prevention of AEs requires identifying priorities and then using the so-called “systems approach,” which attributes AEs to the whole hospital lacking enough safety features and work of teams, and therefore the “system” and not individuals become the subject of interventions. Hospital management has a key role in this strategies. Cost-effective retrospective hospital audits for AEs can be organized by a chart review of a sample of the admitted patients stratified by a priori risk defined through administrative records, routine in hospitals. However, retrospective reviews should be supplemented by analysis of ongoing events and near misses, all leading to focused interventions.
A man 42 years of age was hospitalized due to empyema that was drained with a chest tube. The tube was removed 6 days later because it was draining very little. A chest CT scan after the chest tube was removed showed pleural loculations. The patient was discharged as “improved.” Twelve days later, he was readmitted with pleuritic chest pain and breathlessness. Pleural decortication was performed, and the patient recovered with no further complications.