Pediatric emergencies are a tremendous stressor for emergency physicians – because they are rare, routine is lacking, and children are not small adults. The developer of the Pediatric Emergency Ruler, Prof. Jost Kaufmann, knows this from more than 6,000 missions as an emergency physician, which he has completed for the professional fire department of the city of Cologne and the ADAC (German Automobile Club) ground-based and on the helicopter Christoph Rheinland. Prof. Jost Kaufmann’s main occupation is Senior Physician in Pediatric Anesthesia and Senior Physician in Endoscopy at the Children’s Hospital of the Clinics of the City of Cologne. In July 2022, he received the professorship for pediatric anesthesiology at the Faculty of Health at Witten/Herdecke University. He is also a member of the “Commission for Drug Therapy Safety in Children – KASK” of the DGKJ and the “Commission for Medicinal Products for Children and Adolescents – KAKJ” of the BfArM. He is the initiator and coordinator of the AMWF S2k guideline “Medication Safety in Pediatric Emergencies,” which – like the ERC guidelines – explicitly recommends the Pediatric Emergency Ruler. In the interview, Prof. Kaufmann gives an insight into the conception of the medical device:
What gave you the idea to develop the Pediatric Emergency Ruler PädNFL?
“Actually, there were three impetuses for me to develop the ruler, and with it, a length-based weight estimate with concurrent dose recommendations for pediatric emergencies. These were the clustered observation of medication errors in pediatric emergencies, the problem of imprecise weight estimates by age-based formulas, and percentile curves used in pediatrics. All of this together gave me the idea to create a Develop ruler to be applied to the child lying outstretched, with segments printed on it on which age- and weight-based dose recommendations for emergency medications can be read directly without calculation steps.”
How did you proceed conceptually?
“The design was primarily driven by six themes:
- By estimating body weight from body length using the known percentiles (1), normal weight is obtained, which more accurately estimates a child’s actual (weighed) weight than age-based formulas. (2)
- The crucial volume of distribution for emergency drugs represents the intravascular extracellular volume (EZV). (3)
- Normal weight correlates better with EZV than weighed weight. (4)
- Therefore, for the dosage of emergency medication, the normal weight is more suitable than the weighed weight. (5)
- In obese children, dosing based on weighed weight can lead to overdose, especially of analgesics and sedatives, which is why dosing should be based on normal weight here as well. (6)
- The calculation of the dose is of the greatest importance for threatening errors in the medication of children. (7-10)”
Was there anything comparable before?
“The only similar instrument at the time of my development was the “Broselow Tape” from the USA (Armstrong Medical Industries Inc., Lincolnshire, IL, USA). However, this was never approved or distributed in Europe. Moreover, it was evaluated only in simulation scenarios (11), and here, in addition, it was tested only with respect to a reduction of dosing errors with a deviation of 20% from the recommended dose (12). However, such small deviations are clinically insignificant.
Another disadvantage I have found is that the tape offers important information on the care of children (including appropriate size of equipment, physiological norm values) only in accompanying booklets. In my view, this is not a viable solution. Looking for important information in a companion booklet in a stressful emergency situation may not make sense. To find a solution for practice, I began developing the ‘Pediatric Emergency Ruler’ in 2006.”
Previous awards for Prof. Jost Kaufmann and the PädNFL:
– Winner of the Financial Times 2021 “Health Industry Ideas Park” award
– Rudolf Frey Prize for Emergency Medicine awarded by the DGAI 2021
Where do the percentiles used in the ruler for height and weight development come from?
“The percentiles used in Germany for height and weight development of children originate from surveys of the American Centers for Disease Control and Prevention (CDC), (1) whereas a large study launched in Germany to collect epidemiological data of children (“Kinder- und Jugendgesundheitssurvey – KiGGS”, 2003-2006) did not publish a length-weight relation. (13) However, in a personal conversation with the lead statistician of the study (Dr. H. Stolzenberg, Robert Koch Institute, Berlin), he confirmed after analysis of the raw data that the corresponding distribution data of the KiGSS are identical to those of the American CDC and that these can thus be used for valid estimation of normal weight also for the German children. With the aim of enabling the most precise weight estimates possible in practicable segments, it was possible, with the support of a statistician (Prof. Dr. rer. medic. Martin Hellmich, Institute for Medical Statistics, Informatics and Epidemiology (IMSIE) at the University of Cologne) 11 segments adapted to the decreasing proportional weight gain with increasing body length could be selected in such a way that a maximum of 11 % deviation from the ideal weight could occur (Table 1). (14) An arbitrary number of segments was not possible, because that would have made the area of each segment too small.”
What did you pay particular attention to in the practical design of the ruler?
“From my own experience, I wanted above all to enable users to read all the necessary recommendations and information on each segment directly – without having to take any further steps of their own or look them up elsewhere. Deviations in drug dosages in the dimension of 10% are not clinically relevant, which is why the precision of weight estimation by the ruler in the mentioned form is certainly sufficient. The segments chosen thus represented a good compromise between required precision and practicality determined by readability.”
The specifications on the ruler start at a body length of 44 cm. What about smaller children?
“Smaller children than those with a body length of 44 cm and a weight of 2.4 kg tend not to be encountered in prehospital care and would require segments that are too small to ensure readability of information. Children over 140 cm in length and weighing over 30 kg are no longer a particular challenge for emergency physicians experienced with adults. That’s why we decided to offer PädNFL’s recommendations for the 44 cm to 140 cm body length range.”
Besides length, weight and dosage recommendations, what else can be read from the PedNFL?
“In all of the aforementioned segments, in addition to dose recommendations for all relevant emergency medications, recommendations for appropriate equipment, e.g., respiratory masks and endotracheal tubes, and age-group-specific physiological norm values, such as blood pressure and heart rate, are also integrated. We’ve also printed an illustration and instructions that will allow any medical professional to use the ruler immediately.”
MDR/IVDR is on everyone’s lips. Is the Children’s Emergency Ruler a medical device?
“The German Federal Institute for Drugs and Medical Devices (BfArM) has confirmed that the PädNFL meets the criteria of a medical device when used for dose finding for pediatric emergencies. Accordingly, all the required formalities arising from the Medical Devices Act (MPG) and the Medical Devices Safety Plan Ordinance (MPSV) in accordance with Directive 93/42/EEC were fulfilled for the PädNFL. This includes, for example, conformity assessment procedures, risk assessment, a risk management concept, etc. The PädNFL is registered by Prof. Dr. Jost Kaufmann as a formal manufacturer with the responsible bodies (German Institute for Medical Documentation and Information – DIMDI, No. 0108397). In addition to the measures required for this, the PädNFL is certified by a notified body of the European Union (DQS MED, identification number 0297) and has been granted utility model protection at the German Trademark and Patent Office (DPMA No. 202009011884.3).”