THE CRADLE Vital Sign Alert (VSA) Device - the ALERT is the Lifesaver

More than 50% of global maternal mortality is due to hemorrhage, hypertensive disorders (including Preeclampsia), and sepsis. A standard way to monitor pregnant women’s well-being and diagnose pathologies to identify when clinical intervention is needed, is the monitoring of vital signs (blood pressure and pulse). While this seems quite basic in high-resource settings, it cannot be guaranteed in low-resource contexts where constraints might include the lack of functioning vital sign monitoring devices, no-skilled personnel, or poor training in understanding the measurement results and initiating life-saving interventions.

The CRADLE VSA was developed by hypertension (high blood pressure) experts in the United Kingdom to specifically address these constraints under acknowledgment of the WHO criteria for use in low-resource settings. The CRADLE VSA is semi-automated, low cost, with low-power requirements and high accuracy. It can endure high temperatures and humidity, is robust, and can withstand a fall on the floor even from 2 meters high without breaking. Most importantly, the device is fed with an algorithm that computes the blood pressure with the pulse rate and provides a traffic-light-colored ALERT, based on the shock index (green=patient is ok, yellow=evaluate the need for referral and ensure rechecking of the patient, red=immediate care required). This alert system also allows untrained providers to identify high-risk patients and initiate a timely referral to higher-level clinical care to save lives. A lot of studies showed the effectiveness of the CRADLE VSA in the diagnosis of preeclampsia and other hypertensive pregnancy disorders, hypovolemic shock (e.g. due to hemorrhage), and tachycardia (high pulse rate, which could indicate sepsis). The Cradle VSA has been increasingly used since 2016.

Product and ordering information

• Minimum quantity of 16 CRADLE VSA units per order
• English instructions available
• Select M (medium) or L (large) cuff size
• Not yet for sale within the United States

Regulatory approval information

• Meets WHO guidelines for use in low-resource settings
• Maternova’s CRADLE VSA is CE-marked
• Maternova’s CRADLE VSA fulfills the standards required by the ANSI/AAMI/ISO protocol

FAQ:

How is the CRADLE different from other blood pressure measuring devices?

The CRADLE VSA (Vital Signs Alert) device, a handheld semi-automated vital sign monitor was developed to specifically address gaps in LMICs like training, education, and availability of functioning vital sign devices. Based on a specifically developed algorithm for pregnancy-related complications, the CRADLE does not only monitor vital signs accurately but also signals an ALERT when action is needed. This allows all levels of healthcare providers, including Community Health Workers to take timely, appropriate action, to save lives.

Why was the CRADLE VSA developed?

A significant number of maternal (and fetal) deaths and illnesses globally are due to three conditions: hemorrhage, hypertensive disorders (including Preeclampsia), and sepsis. Bleeding (hemorrhage), especially during or after delivery (postpartum) can lead to maternal death within a couple of hours even in a previously healthy woman. Hypertensive (high blood pressure) pregnancy disorders including Preeclampsia can develop during pregnancy or even postpartum and can lead to fetal growth restriction, preterm birth, placental abruption, maternal organ damage, seizures, and maternal and fetal deaths. Sepsis is a life-threatening condition with organ dysfunction resulting from infection during pregnancy, childbirth, post-abortion, or in the postpartum period. Amongst other conditions, these three pregnancy related diseases can be detected during quality antenatal, perinatal, and postnatal care. However, in many settings the blood pressure devices are not functioning accurately, are broken and the validity of the blood pressure and pulse results depend on the level of training of the health worker. An additional barrier for timely appropriate treatment is the health workers’ recognition of a “normal” healthy result and differentiate this from vital signs that indicate health problems, when action is needed.

How does the CRADLE VSA work?

Hypertension experts from King’s college, UK, developed the CRADLE VSA with especially the Community Health Workers in mind. The CRADLE VSA was designed to be suitable in low resource settings, robust and with low requirements for maintenance. Obtaining reliable results is ensured through the CRADLE’s semi- automated mechanism, leaving not much room for errors. The main lifesaving function, however, is the ALERT system, which is a new, pregnancy- adopted algorithm (computing blood pressure and pulse) based on the Shock Index. The CRADLE gives alert based on the colors of a traffic light

• 🟩 Green = the patient is healthy and well off
• 🟨 Yellow = the results are outside of the safe margins. Check if the patient shows signs of Preeclampsia or other hypertensive disorders (if arrow shows up) or a sign for bleeding or sepsis (if arrow goes down). Evaluate if referral is required. Ensure rechecking of the woman’s vital signs.
• 🟥 Red = the combination of pulse and blood pressure indicates a risk for hypotension (based on bleeding, sepsis or other reasons= arrow shows down) or for hypertension (e.g. due to preeclampsia or other hypertensive disorders= arrow shows up); the patient needs immediate care or referral in a higher level facility

Step-by-step use of the CRADLE VSA

Step 1: Select the correct cuff size according to the upper arm circumference (M or L, guidance see below).

Step 2: Place the lower end of the cuff 2 cm above the patient's elbow, align the cuff so that the cuff’s ca 3 cm long artery mark lies over the patient’s artery (which runs down the inner side of the arm), and fit the cuff closely (not too tight). Ensure that the cuff is at the same height as the patient's heart and the patient’s arm is supported and relaxed.

Step 3: Switch the device on, wait until you see “0” in the display and the arrows start to flash.

Step 4: Start to pump up the cuff, approx. 40 mmHg higher than you think the patient’s upper (systolic) blood pressure value is. You can see the pressure indication on the display. Once you reach the appropriate pressure, you will hear a beep sound and the flashing arrows will disappear. If you have not pumped enough, the flashing arrows will not disappear to indicate that you should pump higher.

Step 5: After pumping, ask the patient to relax, not talk, breathe calmly, and not to engage the arm muscles during the examination, the CRADLE VSA takes the measurement automatically. During the measurement, the pulse indicator flashes on the display and a beep sounds every time a heartbeat is detected.

Step 6: The result, comprising the systolic, the diastolic blood pressure value and the pulse rate is displayed and a longer beep sound is heard. Also look at the explanations in this booklet.

Step 7: Once the measurement is completed, remove the cuff from the patient's arm and switch off the CRADLE VSA.  

What cuff size should I order?

The cuffs of the CRADLE VSA come in two sizes depending on the patient’s upper arm circumferences to ensure accurate measurement results.

• Size M is used with an upper arm circumference of 22 - 32 cm
• Size L is used with an upper arm circumference of 32 - 42 cm

 Is the CRADLE VSA already used with patients?

The CRADLE VSA has been on the market since 2016 and is already in use in many communities, health points, and higher- level hospitals. Additionally, humanitarian and development organizations are increasingly aware of the CRADLE VSA and like to promote it, as it is a robust, easy to use and charge device with only minimal training needs. The CRADLE VSA is increasingly used as its accuracy and features are compelling for different contexts of patient care.

What does CRADLE VSA stand for?

The CRADLE VSA was developed with community health workers in mind, to ensure that women would receive good routine pregnancy care and emergencies would be detected early.

CRADLE VSA stands for Community blood pressure monitoring in Rural Africa &  Asia: Detection of underLying pre-Eclampsia and shock, Vital Signs Alert

Is the product suitable for low-resource settings?

The CRADLE VSA developed specifically to meet the World Health Organization criteria for use in a low-resource setting. It is a low-cost device, with low power requirements. It is also robust, this means it stays accurate even at extremes of temperature and humidity, after being dropped from a height of 2 meters and after being used more than 20,000 times at high pressures.

What is the power source of the CRADLE VSA?

The CRADLE VSA runs using a rechargeable lithium battery which charges with a micro USB port (a standard mobile phone charger). A 4 hour charge lasts for approximately 200 measurements.

How long will the device last?

The CRADLE VSA is a robust device and will last for at least 5 years, estimated over 10,000 measurements.

Can the CRADLE be used in every age group?

This oscillometric blood pressure monitor is intended for measuring non-invasive blood pressure in people aged 12 years or older.

How accurate is the CRADLE VSA?

The VSA can accurately measure blood pressure in pregnant patients including those with known or suspected with Preeclampsia. It combines the advantages of an automatic blood pressure monitor and auscultatory sphygmomanometer designed to provide convenient, accurate and reliable blood pressure measurements according to guidelines of the British Hypertension Society (BHS) and World Health Organization (WHO).

Is there enough evidence for the effectiveness of the CRADLE VSA?

Four separate trials have been completed that demonstrate the effectiveness of the CRADLE VSA for the use in community settings, its accuracy and validity in vital sign monitoring and its contribution to support the reduction of maternal mortality and morbidity. Additionally, the CRADLE’s value for anemia screening during pregnancy was established in one of these studies.

Currently, four additional studies are ongoing. The questions these studies aim to answer are behavior factors and educational needs that might impact the use of the CRADLE, optimal timing of delivery in late preterm preeclampsia, and the CRADLE’s importance in hypertension and malaria detection in non-pregnant refugee populations.

Citations

 The guidelines and evidence based studies include: 

Nathan HL, Boene H, Munguambe K, Sevene E, Akeju D, Adetoro OO, Charanthimath U, Bellad MB, de Greeff A, Anthony J, Hall DR, Steyn W, Vidler M, von Dadelszen P, Chappell LC, Sandall J, Shennan AH; CLIP Working Group. The CRADLE vital signs alert: qualitative evaluation of a novel device designed for use in pregnancy by healthcare workers in low-resource settings. Reprod Health. 2018 Jan 5;15(1):5. doi: 10.1186/s12978-017-0450-y. PMID: 29304812; PMCID: PMC5756409.

The full list of studies and publications can be accessed here.

Product Materials and Instruction Documents 

Maternova Instructions For Use (IFU) are available in Spanish and English. For orders of over 500 units, IFU will be translated into other languages.