Research news and notes

1. Simple intervention in the intensive care unit decreases catheter-related bloodstream infections 

Many neurosurgical patients are admitted to an intensive care unit (ICU) and need a variety of indwelling catheters. Intravascular catheters are a common source of potentially serious infections. In the December 28 issue of the New England Journal of Medicine, Pronovost et al [3] presented the results of an intervention to reduce catheter-related infections in 103 ICUs, mostly in Michigan, over an 18-month period. The interventions were simple and well established: hand washing, using full barrier precautions during insertion of central lines, cleaning the skin with chlorhexidine, avoiding the femoral site if possible, and removing unnecessary catheters. The intervention involved mainly constant education, feedback, communication with the providers, and such interventions as letters to hospital chief executive officers to support stocking chlorhexidine. The active intervention lasted 3 months, but information was collected for 18 months to see if the intervention had lasting effects. The main outcome measured was the rate of infections per 1000 catheter days. Information was accumulated for the total of 375757 catheter days. The median rate of infection dropped from 2.7 to 0 and the mean rate of infection changed from 7.7 to 2.3 per 1000 catheter days. The difference between the mean and the median reflects differences between the rates in the various hospitals. In most institutions, the rate dropped to zero over the course of the intervention and stayed at zero, resulting in the zero median. The simple interventions seem to have changed the local culture because the benefit continued well beyond the period of active intervention. The benefit was greater in smaller hospitals.

This study demonstrates that dramatically better outcomes can be achieved by careful implementation of known good practices. Probably no topic in intensive care is more important than prevention of infections. Severe infections in ICUs are damaging beyond their effect on specific patients—the presence and spread of hospital-acquired, multidrug-resistant organisms are problems that must be addressed at all levels.

2. If you use it, you do not lose it 

It is well known that a decline in cognitive abilities with age eventually results in a decreased capacity for independent function—instrumental activities of daily living (IADL). In the December 20 issue of JAMA, Willis et al [4] looked at the effect of cognitive training on prevention of the loss of IADL in the elderly.

The authors recruited a sample of 2832 volunteers, with a mean age of 73.6 years, who were all living independently at that time. They were divided into 4 groups—those receiving either memory training, reasoning training, or speed of response training and those with no intervention (control). The functional outcomes measured were not direct performance on the same tasks, but other parameters, such as IADL, everyday problem solving, etc. Follow-up continued up to 5 years after the brief treatments. At the end of the trial, 67% of the original participants were reevaluated. The rest had died or dropped out for other reasons. There was no significant difference between the groups in the dropout rate. Participants maintained the benefit of each intervention at 5 years follow-up. There was an additional apparent benefit—the trained elderly demonstrated less difficulty with IADL at 5 years follow-up. The benefit was significant only in the reasoning training group, although the trend could be seen in other groups. The study was complex, and the benefit was only apparently significant in one group and only at 5 years. Therefore, the absolute benefit of the short period of training was relatively small. I find the existence of any benefit of a short cognitive training period on function years later amazing. The fact that the treated population was elderly underscores the importance of the findings. The finding that each intervention resulted in an immediate improvement in the specific cognitive ability trained reinforces the validity of the data in this study. If 10 sessions of training had such a beneficial and long-lasting effect on the elderly participants, what could be the effect of more training or continued intellectual stimulation?

A small study published in the recent issue of The Journal of Applied Research [1] demonstrated that a 10-week regimen of intense aerobic exercise in the elderly (mean age, around 83 years) resulted in a significant decrease in the systolic blood pressure in participants compared with controls. The studies are related in one small way—intense training of any kind is beneficial in old age. Maybe the classic idle retirement is itself a disease?

3. Heterotopic ossification and spontaneous fusion after cervical artificial disk replacement 

Probably the main rationale for choosing a disk replacement over an anterior cervical diskectomy and fusion is the maintenance of segmental mobility with the artificial disk. In the November issue of Spine, Mehren et al present 1-year follow-up of 54 patients who received 77 total cervical disk replacements (TCDRs) in 2 German centers [2]. Only in 26 of the 77 treated segments was there no heterotopic ossification. In 7 cases, there was spontaneous fusion of the operated segment. Inasmuch as the degree of ossification was substantial in many additional cases, the long-term fusion rates may be even higher. It is ironic that “fusion rate,” which was a measure of success for anterior cervical diskectomy and fusion, is now a measure of failure for TCDR. Further study of the long-term cervical mobility is key before TCDR can be recommended as a method that preserves segmental motion.