Quantifying sputum production in intensive therapy

Introduction

Sputum is essential for the protection of the respiratory tract but also plays a significant role in the pathophysiology of lung disease [1]. This is evident in critical care where high sputum loads contribute to respiratory failure [2]. The quantity of sputum produced by a patient can impact on key decisions such as weaning, extubation and discharge. We undertook a survey to establish whether there was a consensus on how we quantify sputum on our intensive therapy unit (ITU).

Methods

We conducted a multidisciplinary team questionnaire of our 28-bed tertiary ITU. Staff were asked how they quantified sputum load in intubated patients. They were also asked to rate statements on a five-point scale pertaining to sputum characteristics. The results were analysed in Excel 2010.

Results

One hundred members of staff completed the sputum production in intensive therapy (SPIT) questionnaire (21% doctors, 71% nurses, 8% physiotherapists). Sputum load was deemed to be important or essential by more than 95% of respondents when making decisions to extubate or decanulate. The quantification of sputum was inconsistent: 39% of respondents counted the frequency of suctioning, 24% measured the quantity of sputum in the suction tubing, whereas 25% used another method. An effective cough, consistency and colour were felt to be more important features of sputum than blood staining.

Conclusion

Our results showed a very high level of agreement on the importance of knowing sputum load for decisions to extubate, decanulate or discharge from the ITU. In contrast, there was little consensus on how we should quantify sputum load in ventilated patients. This lack of standard approach may contribute to uncertainty in the clinical decision-making process. We have developed an objective sputum scoring system. Components identified as important by our survey such as suction frequency, sputum consistency and colour are included. We have recognised the benefits of the standardised Bristol stool chart to facilitate communication and believe this can be achieved with sputum load in ventilated patients.