Early Warning Score Observation

Defines the Early Warning Score observation class and its standard behaviour and policy triggers based on the UK NEWS standard.

class ews.nh_clinical_patient_observation_ews(pool, cr)

Represents an Early Warning Score observation which stores a group of physiological parameters measured from the patient that together determine a score that serves as an indicator of the illness current acuity.

The basis of the scoring system are the following six parameters: respiratory rate, oxygen saturations, temperature, systolic blood pressure, pulse rate and level of consciousness.

avpu_text

Parameters:

• selection – specifies the possible values for this field. It is given as either a list of pairs (value, string), or a model method, or a method name.
• selection_add – provides an extension of the selection in the case of an overridden field. It is a list of pairs (value, string).

The attribute selection is mandatory except in the case of related fields or field extensions.

blood_pressure_diastolic

blood_pressure_systolic

body_temperature

The precision digits are given by the attribute

Parameters:digits – a pair (total, decimal), or a function taking a database cursor and returning a pair (total, decimal)

bp_display

Basic string field, can be length-limited, usually displayed as a single-line string in clients

Parameters:

• size (int) – the maximum size of values stored for that field
• translate (bool) – whether the values of this field can be translated

calculate_score(*args, **kwargs)

Computes the score and clinical risk values based on the NEWS parameters provided.

It will return as extra information the presence of any Red Score parameter within the data. (any parameter that scores 3)

Parameters:ews_data (dict) – The NEWS parameters: respiration_rate, indirect_oxymetry_spo2, body_temperature, blood_pressure_systolic, pulse_rate, oxygen_administration_flag and avpu_text Returns:score, clinical_risk and three_in_one Return type:dict

can_decrease_obs_frequency(*args, **kwargs)

Determines whether or not the frequency of the patients observations can be reduced to a lower value. There are certain situations where this is allowed depending on the ward’s policy.

Parameters:

• cr –
• uid –
• patient_id –
• threshold_value –
• context –

Returns:

change_activity_frequency(*args, **kwargs)

Convenience that allows you to pass a ‘case’ instead of a ‘frequency’ and the method will do the lookup for you.

See nh_observations.nh_clinical_extension .nh_clinical_api_extension.change_activity_frequency.

Parameters:

• cr –
• uid –
• patient_id –
• name –
• case –
• context –

Returns:

clinical_risk

Basic string field, can be length-limited, usually displayed as a single-line string in clients

Parameters:

• size (int) – the maximum size of values stored for that field
• translate (bool) – whether the values of this field can be translated

complete(*args, **kwargs)

It determines which acuity case the current observation is in with the stored data and responds to the different policy triggers accordingly defined on the _POLICY dictionary:

{'ranges': [0, 4, 6], 'case': '0123', --> Used with bisect to
determine the acuity case based on the score.
'frequencies': [720, 240, 60, 30], --> frequency of recurrency
of the NEWS observation, based on the case.
'notifications': [...],
   Information sent to the trigger_notifications method,
   based on case.
'risk': ['None', 'Low', 'Medium', 'High']} --> Clinical risk
of the patient, based on case.

All the case based lists work in a simple way: list[case] –> value used

After the policy triggers take place the activity is completed and a new NEWS activity is created. Then the case based frequency is applied, effectively scheduling it.

In the case of having a partial observation we won’t have a new frequency so the new activity is scheduled to the same time the one just completed was, as the need for a complete observation is still there.

Returns:True Return type:bool

concentration

convert_case_to_risk(case)

cpap_peep

create_activity(*args, **kwargs)

When creating a new activity of this type every other not completed or cancelled instance related to the same patient will be automatically cancelled.

Returns:activity id. Return type:int

create_next_obs(*args, **kwargs)

Creates a new observation and activity based on a given closed observation activity.

If the previous observation is partial, the new observation is scheduled for the same time as the old one, in other words, there is a good chance it will be due right away. If the previous observation is not a partial then it will be scheduled based on the frequency implied by the clinical risk of the previous observation.

It only makes sense to create the next observation activity based on an activity for an observation of the same type as this one. An exception will be raised if the same type of activity is not passed.

If the observation is neither completed or cancelled then it is still open and a new observation activity should not be created, thus an exception will be raised.

Parameters:previous_obs_activity – Returns:

device_id

The value of such a field is a recordset of size 0 (no record) or 1 (a single record).

Parameters:

• comodel_name – name of the target model (string)
• domain – an optional domain to set on candidate values on the client side (domain or string)
• context – an optional context to use on the client side when handling that field (dictionary)
• ondelete – what to do when the referred record is deleted; possible values are: 'set null', 'restrict', 'cascade'
• auto_join – whether JOINs are generated upon search through that field (boolean, by default False)
• delegate – set it to True to make fields of the target model accessible from the current model (corresponds to _inherits)

The attribute comodel_name is mandatory except in the case of related fields or field extensions.

flow_rate

The precision digits are given by the attribute

Parameters:digits – a pair (total, decimal), or a function taking a database cursor and returning a pair (total, decimal)

get_case(observation)

Return an integer based on the clinical risk of the observation to be used as an index when accessing elements of _POLICY.

Parameters:observation – EWS observation Returns:case Return type:int

classmethod get_data_visualisation_resource()

Returns URL of JS file to plot data visualisation so can be loaded on mobile and desktop

Returns:URL of JS file to plot graph Return type:str

get_date_scheduled_for_refusal(*args, **kwargs)

Get the expected schedule date for a new observation triggered based on the passed completion date of the previous observation and it’s frequency.

Parameters:

• previous_activity_completed_datetime (str) – Value for the date terminated field of the previous completed observation.
• frequency (int) – Frequency in minutes.

Returns:

get_form_description(*args, **kwargs)

Returns a description in dictionary format of the input fields that would be required in the user gui to submit the observation.

Parameters:patient_id (int) – patient id Returns:a list of dictionaries Return type:list

get_frequency_for_refusal(*args, **kwargs)

Get the expected frequency for a new observation triggered by completion of the passed one if it is also refused.

Parameters:previous_obs_activity ('nh.activity' record) – Returns:

get_last_case(*args, **kwargs)

Checks for the last completed NEWS for the provided patient and returns the acuity case:

0 - No Risk
1 - Low Risk
2 - Medium Risk
3 - High Risk

Returns:False or the acuity case Return type:int

get_last_full_obs_activity(*args, **kwargs)

Gets the most recent full observation.

Parameters:spell_activity_id (int) – Returns:observation activity Return type:nh.activity

get_notifications(*args, **kwargs)

Get notifications that should be triggered upon completion of the passed activity for an EWS observation.

Parameters:activity – activity referencing an EWS observation Returns:a list of dictionaries representing notifications Return type:list

get_submission_message(*args, **kwargs)

Override of nh.clincal.patient.observation method.

Returns:

handle_o2_devices(*args, **kwargs)

Checks the current state of supplemental oxygen device sessions on the related spell.

It completes the sessions if the current NEWS does not have the oxygen administration flag up.

It completes any session with an oxygen administration device type that does not match the NEWS device.

It starts a new session if the NEWS device provided does not have already an open one related to the spell.

Parameters:activity_id (int) – activity id.

indirect_oxymetry_spo2

is_partial

lookup_adjusted_frequency_for_patient_refusal(case, frequency=None)

Lookup the frequency adjusted to take into account the fact that the patient is refusing observations. There are some cases where this needs to be different to the usual frequency dictated by the policy which necessitates this lookup.

Parameters:

• case (int or str) – Either an int representing the clinical risk or a str representing a special state such as ‘Transfer’. See field:nh_ews._POLICY: and frequencies.py.
• frequency (int) – Frequency in minutes.

Returns:

mews_score

niv_backup

niv_epap

niv_ipap

o2_display

Basic string field, can be length-limited, usually displayed as a single-line string in clients

Parameters:

• size (int) – the maximum size of values stored for that field
• translate (bool) – whether the values of this field can be translated

order_by

oxygen_administration_flag

patient_has_spell(*args, **kwargs)

pulse_rate

respiration_rate

score

score_display

Basic string field, can be length-limited, usually displayed as a single-line string in clients

Parameters:

• size (int) – the maximum size of values stored for that field
• translate (bool) – whether the values of this field can be translated

submit(*args, **kwargs)

three_in_one

update_next_obs_after_partial(*args, **kwargs)

Updates the frequency and date scheduled of the newly created next_obs_activity from their default values to their correct values based on previous observations and the refusal status.

Parameters:

• partial_obs_activity ('nh.activity' record) – Observation activity expected to be a partial and the most recently completed observation for the spell.
• next_obs_activity ('nh.activity' record) – Observation activity expected to be the most recently created one triggered by the passed partial.

Returns: