clinmon: Hemodynamic Indices Calculated From Clinical Monitoring...

In clinmon: Hemodynamic Calculations from Clinical Monitoring

Description

clinmon() uses a continuous recording and returns a dataframe with hemodynamic indices for every period, epoch or block depending on the chosen output. Calculates COest, CPPopt, CVRi, Dx, Mx, PI, PRx, PWA, RI, and Sx (see Hemodynamic indices).

Usage

clinmon(df, variables,
trigger = NULL, deleter = NULL,
blocksize = 3, epochsize = 20,
overlapping = FALSE, freq = 1000,
blockmin = 0.5, epochmin = 0.5,
output = "period", fast = FALSE)

Arguments

df	Raw continuous recording with all numeric data and first column has to be time in seconds. (dataframe)
variables	Defining the type and order of the recorded variables as a list. Middle cerebral artery blood velocity ('mcav'), Arterial blood pressure ('abp'), cerebral perfusion pressure ('cpp'), intracranial pressure ('icp'), and heart rate ('hr') is currently supported. (list)
trigger	Trigger with two columns: first is start, and second is end of periods to be analyzed. Every row corresponds to a period. Default is NULL, which results in analysis of the full dataframe. (dataframe)
deleter	Deleter with two columns: first is start and second is end of period with artefacts, which need to be deleted. Every row is a period with artefacts. Default is NULL. (dataframe)
blocksize	Length of a block, in seconds. Default is 3. (numeric)
epochsize	Size of epochs in number of blocks. Default is 20. (numeric)
overlapping	The number of block which should overlap when calculating correlation based indices, and remain blank if overlapping calculations should not be utilized. Default is FALSE. (numeric)
freq	Frequency of recorded data, in Hz. Default is 1000. (numeric)
blockmin	Minimum measurements required to create a block in ratio. Default is 0.5 corresponding to 50%. If the block holds less than the defined ratio the block will be omitted. (numeric)
epochmin	Minimum number of blocks required to create an epoch in ratio. Default is 0.5 corresponding to 50%. If the epoch holds less than the defined ration the epoch will be omitted. (numeric)
output	Select what each row should represent in the output. Correlation based indices are not presented when selecting blocks for every row. Currently 'block', 'epoch', 'period' or 'cppopt' is supported. Default is 'period'. (string)
fast	Select if you want the data to aggregated before analysis resulting in a faster, but perhaps more imprecise run, in Hz. Default is FALSE. (numeric)

Details

Using a continuous raw recording, clinmon() calculates hemodynamic indices for every period, epoch or block depending on the chosen output.

View(data)

time	abp	mcav
7.00	78	45
7.01	78	46
...	...	...
301.82	82	70
301.83	81	69

To calculate the indices insert the data and select the relevant variables.

clinmon(df=data, variables=c("abp","mcav"))

See Value for output description.

Value

Returns a dataframe with the results, with either every blocks, epochs or periods as rows, depending on the chosen output.

Column	Description
period	The period number corresponding to the row-number in the trigger file.
epoch	The epoch number, or if period is chosen as output it reflects the number of epochs in the period.
block	The block number, or if period or epoch is chosen as output it reflects the number of blocks in the period or epoch.
time_min	The minimum time value or the period, epoch or block.
time_max	The maximum time value or the period, epoch or block.
missing_percent	The percentage of missing data in the period, epoch or block.
*_mean	The mean value of each variable for the period, epoch or block.
*_min	The minimum value of each variable for the period, epoch or block.
*_max	The maximum value of each variable for the period, epoch or block.
*	The indices in each column.

Hemodynamic indices

COest | Estimated cardiac output

Required variables: abp, hr; Required output: -.

Estimated cardiac output (COest) is calculated by utilizing the method described by Koenig et al. [1]:

COest = PP / (SBP+DBP) * HR

PP: Pulse pressure; SBP: systolic blood pressure; DBP: diastolic blood pressure; HR: heart rate.

CPPopt | Optimal cerebral perfusion pressure

Required variables: abp, icp; Required output: period.

Optimal cerebral perfusion pressure (CPPopt) is calculated utilizing the method described by Steiner et al. [2]. The CPPopt return NA if CPPopt is the maximum or minimum CPP investigated. CPPopt is recommended to only be calculated after 'several hours' of recording:

CPPopt = 5 mmHg_CPP_interval_with_lowest_mean_PRx )

CPP: cerebral perfusion pressure; PRx: Pressure reactivity index.

CVRi | Cardiovascular resistance index

Required variables: abp, mcav; Required output: -.

Cardiovascular resistance index (CVRi) is calculated utilizing the method described by Fan et al. [3]:

CVRi = mean ABP / mean MCAv

ABP: arterial blood pressure; MCAv: middle cerebral artery blood velocity.

Dx | Diastolic flow index

Required variables: cpp/abp, mcav; Required output: epoch, period.

Diastolic flow index (Dx) is calculated utilizing the method described by Reinhard et al. [4]:

Dx = cor( mean CPP / min MCAv )

Dxa = cor( mean ABP / min MCAv )

cor: correlation coefficient; CPP: cerebral perfusion pressure; ABP: arterial blood pressure; MCAv: middle cerebral artery blood velocity.

Mx | Mean flow index

Required variables: cpp/abp, mcav; Required output: epoch, period.

Mean flow index (Mx) is calculated utilizing the method described by Czosnyka et al. [5]:

Mx = cor( mean CPP / mean MCAv )

Mxa = cor( mean ABP / mean MCAv )

cor: correlation coefficient; CPP: cerebral perfusion pressure; ABP: arterial blood pressure; MCAv: middle cerebral artery blood velocity.

PI | Gosling index of pulsatility

Required variables: mcav; Required output: -.

Gosling index of pulsatility (PI) is calculated utilizing the method described by Michel et al. [6]:

PI = (systolic MCAv - diastolic MCAv) / mean MCAv

MCAv: middle cerebral artery blood velocity.

PRx | Pressure reactivity index

Required variables: abp, icp; Required output: epoch, period.

Pressure reactivity index (PRx) is calculated utilizing the method described by Czosnyka et al. [7]:

PRx = cor( mean ABP / mean ICP )

cor: correlation coefficient; CPP: cerebral perfusion pressure; ICP: intracranial pressure.

PWA | Pulse wave amplitude

Required variables: cpp/icp/abp/mcav; Required output: -.

Pulse wave amplitude (PWA) is calculated utilizing the method described by Norager et al. [8]:

PWA = systolic - diastolic

RI | Pourcelots resistive (resistance) index

Required variables: mcav; Required output: -.

Pourcelots resistive (resistance) index (RI) is calculated utilizing the method described by Forster et al. [9]:

RI = (systolic MCAv - diastolic MCAv) / systolic MCAv

MCAv: middle cerebral artery blood velocity.

Sx | Systolic flow index

Required variables: cpp/abp, mcav; Required output: epoch, period.

Systolic flow index (Sx) is calculated utilizing the method described by Czosnyka et al. [5]:

Sx = cor( mean CPP / systolic MCAv )

Sxa = cor( mean ABP / systolic MCAv )

cor: correlation coefficient; CPP: cerebral perfusion pressure; ABP: arterial blood pressure; MCAv: middle cerebral artery blood velocity.

References

1. Koenig et al. (2015) Biomed Sci Instrum. 2015;51:85-90. (PubMed)

2. Steiner et al. (2002) Crit Care Med. 2002 Apr;30(4):733-8. (PubMed)

3. Fan et al. (2018) Front Physiol. 2018 Jul 16;9:869. (PubMed)

4. Reinhard et al. (2003) Stroke. 2003 Sep;34(9):2138-44. (PubMed)

5. Czosnyka et al. (1996) Stroke. 1996 Oct;27(10):1829-34. (PubMed)

6. Michel et al. (1998) Ultrasound Med Biol. 1998 May;24(4):597-9. (PubMed)

7. Czosnyka et al. (1997) Neurosurgery. 1997 Jul;41(1):11-7; discussion 17-9. (PubMed)

8. Norager et al. (2020) Acta Neurochir (Wien). 2020 Dec;162(12):2983-2989. (PubMed)

9. Forster et al. (2017) J Paediatr Child Health. 2018 Jan;54(1):61-68. (PubMed)

Examples

data(testdata)
clinmon(df.data10, variables=c('abp','mcav','hr'), freq=10)

clinmon documentation built on Feb. 4, 2021, 5:06 p.m.