Elsevier

Journal of Critical Care

Volume 22, Issue 3, September 2007, Pages 219-228
Journal of Critical Care

Health Services Research
Sedation and weaning from mechanical ventilation: effects of process optimization outside a clinical trial

https://doi.org/10.1016/j.jcrc.2007.01.001Get rights and content

Abstract

Purpose

We studied the effects of reorganization and changes in the care process, including use of protocols for sedation and weaning from mechanical ventilation, on the use of sedative and analgesic drugs and on length of respiratory support and stay in the intensive care unit (ICU).

Materials and Methods

Three cohorts of 100 mechanically ventilated ICU patients, admitted in 1999 (baseline), 2000 (implementation I, after a change in ICU organization and in diagnostic and therapeutic approaches), and 2001 (implementation II, after introduction of protocols for weaning from mechanical ventilation and sedation), were studied retrospectively.

Results

Simplified Acute Physiology Score II (SAPS II), diagnostic groups, and number of organ failures were similar in all groups. Data are reported as median (interquartile range).Time on mechanical ventilation decreased from 18 (7-41) (baseline) to 12 (7-27) hours (implementation II) (P = .046), an effect which was entirely attributable to noninvasive ventilation, and length of ICU stay decreased in survivors from 37 (21-71) to 25 (19-63) hours (P = .049). The amount of morphine (P = .001) and midazolam (P = .050) decreased, whereas the amount of propofol (P = .052) and fentanyl increased (P = .001). Total Therapeutic Intervention Scoring System-28 (TISS-28) per patient decreased from 137 (99-272) to 113 (87-256) points (P = .009). Intensive care unit mortality was 19% (baseline), 8% (implementation I), and 7% (implementation II) (P = .020).

Conclusions

Changes in organizational and care processes were associated with an altered pattern of sedative and analgesic drug prescription, a decrease in length of (noninvasive) respiratory support and length of stay in survivors, and decreases in resource use as measured by TISS-28 and mortality.

Introduction

Most critically ill patients receive sedative and analgesic drugs to attenuate discomfort and pain. The excessive use of sedatives and analgesics prolongs the use of mechanical ventilation and the length of stay (LOS) in the intensive care unit (ICU) and increases costs [1], [2], whereas strategies to reduce the use of sedatives and analgesics may improve the outcome [3], [4]. Monitoring the depth of sedation is difficult and is based on clinical assessments of patients' behavior, tolerance of therapy, and physiologic parameters [1]. More structured assessment can be achieved with the introduction of sedation scores, which evaluate the response to a defined external stimulus [5]. Drawbacks of these tools are their subjectivity, lack of standardization of stimuli for the assessment of sedation, and the risk of unnecessarily deep sedation due to problems in assessing deeply sedated or pharmacologically paralyzed patients.

The duration of mechanical ventilation is closely related to the use of protocols for sedation [4], [6]. Using protocols for weaning from mechanical ventilation may additionally help to shorten the time patients remain on the ventilator [7], [8]. However, not all studies have demonstrated a similar benefit [9]. Such discrepancies may be related to different patient populations, as well as to the ability to evaluate the current performance and to implement interventions designed to improve the quality of ICU care [10].

In addition, results obtained in randomized, controlled studies are often not translated into clinical practice [11]. Reasons include lack of interactive education [12], [13]; insufficient awareness of potential benefit, real and perceived risks, uncertainty about responsibility for implementation, and lack of enabling and reinforcing strategies [14]; unfamiliarity with the protocols; and the subjective perception that case-targeted, individualized treatment is preferable [15]. Nevertheless, an institutional approach to the care of patients requiring mechanical ventilation—including an evidence-based clinical pathway, protocols for weaning and sedation use, and designation of people to manage and monitor such efforts—has resulted in improved outcomes, such as reduced duration of mechanical ventilation and reduced ICU and hospital LOS and mortality rates, and in substantial cost savings [16].

Focusing on better monitoring and on implementation of protocols for sedation and weaning from mechanical ventilation, we studied the effect of a multimodular process optimization on the use of drugs for sedation and analgesia, and on the length of mechanical ventilation and stay in the ICU. Because intensive care is an extremely multifactorial entity, it is likely that optimizing multiple factors associated with patient care has a greater potential to improve outcome than single interventions. Single protocols can usually only demonstrate a benefit when other important processes are standardized. As an example, a protocol for weaning patients from mechanical ventilation is unlikely to prove a benefit when other processes such as sedation, hemodynamic management, infection control and communication are not regulated and standardized. Improvement in staff perceptions related to a proposed procedural protocol has been associated with fewer errors and improved outcome [17]. In addition, an implementation program has improved adherence to a mechanical ventilation weaning protocol in critically ill patients [18]. Recently, it has been shown that the implementation of “bundles” of protocols is feasible and is associated with a change in therapy and outcome in specific patient groups [19], [20].

We implemented changes in ICU organization, which resulted in increased specialist presence. With increased specialist presence, patients are more frequently evaluated [21], [22], [23], [24], [25]. When protocols are implemented, patient evaluation is more likely to result in therapeutic consequences [4], [26]. With better cardiovascular and respiratory monitoring, it is increasingly likely that information will lead to a therapeutic intervention. The interrelationships between different aspects of care increase the chances that multiple interventions will have better success.

We initiated the changes by revising organizational, structural, and treatment concepts. Afterwards, protocols for sedation and weaning from mechanical ventilation were developed and implemented. Outcome and resource use parameters were analyzed before and after each of the changes had been implemented. We hypothesized that optimization of clinical and organizational processes is associated with (1) reductions in LOS on mechanical ventilation and in the ICU without increases in mortality and (2) decreased drug and overall costs.

Section snippets

Materials and methods

Our ICU is a mixed medical-surgical unit (the only ICU for adult patients in this 1000-bed university hospital) and has 30 beds. All types of surgery are performed, including heart, liver, and kidney transplantation, but excluding major burns. Informed consent for this study was waived by the local Ethics Committee due to the observational, noninterventional design.

At the time the study began, an established quality assurance initiative had been in place in the ICU since 1997. This initiative

Results

Patient characteristics are displayed in Table 2. There were no differences between the groups with respect to Simplified Acute Physiology Score II (SAPS II), emergency admissions, diagnostic groups, total number of organ failures, and the fraction of surgical and medical patients. The median age of patients at implementation II was higher (67 [58-75] years) than at baseline (63 [52-72] years) and at implementation I (62 [50-70] years) (P = .013).

The amount of morphine (38 [18-61] mg per

Discussion

The main finding of this study was a more-than-50% reduction in mortality within 27 consecutive months, which was not explained by a gross change in the patient population but was accompanied by a shorter LOS in survivors and a reduction in resource use. This suggests that the change in overall management strategies, including the introduction of treatment protocols, was beneficial—even when not associated with a clinical trial.

The significance of the observations in this study is limited by

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    The study was supported by the departmental research fund.

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