clinmon {clintools}R Documentation

Hemodynamic Indices Calculated From Clinical Monitoring (clinmon)

Description

clinmon() uses a continuous recording and returns a dataframe with hemodynamic indices for every period, epoch or block depending on the input. 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. It is necessary that time is the first row. (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.

The columns of the output are:

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 = The 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]:

Dxc = 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]:

Mxc = 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]:

Sxc = 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)
[Package clintools version 0.9.10.1 Index]