Impedance Pneumography Signal Quality Index Dataset
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Table of Contents
=================

  * [The Dataset](#the-dataset)
  * [Revisions](#revisions)
  * [Description](#description)

# The Dataset

The Impedance Pneumography Signal Quality Index Dataset was first reported in the following publication:

Charlton, P.H. et al. An impedance pneumography signal quality index: design, assessment and application to respiratory rate monitoring, [under review], 2020

In this publication it was used to assess the performance of a signal quality index for the impedance pneumography signal. The dataset was extracted from the much larger [MIMIC III matched waveform Database](https://archive.physionet.org/physiobank/database/mimic3wdb/matched/), which was acquired from critically-ill patients during hospital care at the Beth Israel Deaconess Medical Centre (Boston, MA, USA). The 100 recordings within the dataset, each of 1-hour duration, each contain:
  * Physiological signals: the impedance pneumography respiratory signal (ImP), photoplethysmogram (PPG) and electrocardiogram (ECG). These are sampled at 125 Hz.
  * Physiological parameters, such as the heart rate (HR), pulse rate (PR), respiratory rate (RR), and blood oxygen saturation level (SpO2). These are sampled at 1 Hz.
  * Fixed parameters, such as age, sex, ward and patient ID
  * Manual annotations of breaths, and RRs calculated from these: A single annotator manually annotated individual breaths in approximately five 32 sec segments of each recording using the impedance respiratory signal.

The dataset is distributed in Matlab (r) format.

For more information about the dataset, please contact author at:
pc657@medschl.cam.ac.uk .

# Revisions

R1: 	2017-Aug-06 		initial release

## Description
### Matlab (r) Format
The *mimic_imp_sqi_data.mat* file contains the following subset of the dataset in a single Matlab (r) variable named *data*. The following are provided for each of the 100 recordings:
* *ekg*:   Lead II ECG signal. Each signal is provided in a structure, where the *v* field denotes the signal values, and *fs* is the sampling frequency.
* *ppg*:   Photoplethysmogram signal
* *ref.resp_sig.imp*:  Impedance respiratory signal
* *ref.ann*:  Manual annotations of breaths provided by a single annotator. A vector of sample numbers is provided (*breath_els*), which correspond to the signal sample numbers. Breaths were only annotated in certain segments of the signal, rather than the whole signal: the start and end samples of each segment in which breaths were annotated are provided in *win_start_els* and *win_end_els*. RRs calculated from the manual annotations are provided (*rr*, one per window).
* *ref.params*:  Physiological parameters: *rr* (respiratory rate, derived by the monitor from the impedance signal, breaths per minute), *hr* (heart rate, derived from the ECG, beats per minute), *pr* (pulse rate, derived from the PPG, beats per minute), *spo2* (blood oxygen saturation level, %).
* *fix*: A structure of fixed variables: *id* (the MIMIC III matched waveform database subject ID and recording identifier), *loc* (the ward location), and download source (specified for both the waves and numerics).

Further details on the contents of each file are provided [here](https://archive.physionet.org/tutorials/creating-records.shtml).