Introduction of a high dependency unit at a large paediatric and adolescent medicine department

Discussion

We found that 5 % of children admitted to the Department of Paediatrics and Adolescent Medicine were admitted to the PHDU. This was five times higher than the number requiring admission to the ICU. The number of transfers from the Department of Paediatrics and Adolescent Medicine to the ICU was stable from the five-year period before to the five-year period after the opening of the PHDU, but the composition of patients in the ICU changed in a way that may indicate more appropriate use of ICU beds. A lower proportion of patients with diabetic ketoacidosis and sepsis were transferred to the ICU, while a higher proportion of the children who were transferred to the ICU for respiratory problems required invasive mechanical ventilation.

The number of admissions at the PHDU increased every year until 2019. It then fell slightly in 2020 but increased sharply in 2021, largely in connection with a widespread epidemic of respiratory syncytial virus (RSV) that year. Many of the paediatric RSV patients were admitted to the PHDU for CPAP treatment. The decrease in 2020 was probably due to the COVID-19 pandemic, when fewer children were hospitalised due to the reduced incidence of other viral infections as a result of infection control measures (8).

It is estimated that 10 % of patients admitted to paediatric and adolescent medicine departments will need to be admitted to a PHDU (4). We observed a gradual increase in use of the PHDU in the years immediately following the opening of the unit at Haukeland University Hospital. This trend has also been seen at hospitals in England (6). However, use is still slightly below what was expected. The Norwegian standard for paediatric high dependency care recommends that children who need oxygen supplementation in the form of high-flow nasal cannula (HFNC) therapy should be admitted to a PHDU (4). At the Department of Paediatrics and Adolescent Medicine at Haukeland University Hospital, however, such treatment is carried out on general wards, which may partly explain the discrepancy between the estimated and actual need for paediatric high dependency care. We found that the median stay at the PHDU was just less than one day, i.e. slightly less than the expectation in the Norwegian standard for paediatric high dependency care of 1–2 days (4) as well as figures from England, where the average stay was 1.8 days (9).

In the ICU, no major differences were recorded in the number of paediatric medical admissions over the past ten years. This is in contrast to figures from England for the period 2001–10, which show a gradual decrease in the number of ICU admissions after the opening of PHDUs (9). This trend has also been observed following the opening of high dependency units for adults (3). For most of the diagnostic groups, the number of admissions was almost the same or slightly lower in the five-year period after the opening of the PHDU, except for the diagnostic group diabetic ketoacidosis. However, the incidence of diabetic ketoacidosis increased sharply during the period of the study, and although the number admitted to the ICU rose from eight to twelve in the five-year periods before and after the opening of the PHDU, this represented a reduction in the percentage with diabetic ketoacidosis who were admitted to the ICU from the Department of Paediatrics and Adolescent Medicine. This is in line with the national expectation that diabetic ketoacidosis can be treated in a PHDU(4).

The only diagnostic group with a marked increase in the number of ICU admissions was among children given invasive respiratory support, which is not available in the PHDU and thus indicates an appropriate use of ICU beds. Several of these patients required invasive mechanical ventilation following operations or procedures under anaesthesia, often as part of a complicated course of illness. The increase in this group is consistent with reports indicating that the hospital population is becoming more severely ill, requiring more resources, and that the need for ICU beds is growing (5). In almost half of paediatric ICU patients, the ICU stay was at the beginning of the hospital stay, and many patients need initial stabilisation in the ICU, regardless of how well the PHDU functions.

Many patients in both the PHDU and the ICU are admitted due to respiratory problems. Non-invasive ventilation support can be provided in the PHDU and can thus help to relieve the workload of the ICU. The number of children who only received CPAP treatment in the ICU and did not require invasive mechanical ventilation decreased in the five-year period after the PHDU was opened. The number of children who need CPAP varies considerably from year to year, and this is often closely linked to winter epidemics of viral respiratory infections. The observation period in our study is relatively short, and it is too early to conclude whether the introduction of a PHDU has reduced the workload of the ICU in relation to children requiring CPAP treatment.

Suspected sepsis is the second most common diagnostic group in the PHDU, as was also the case in the adult population at the high dependency unit at Akershus University Hospital in 2014 (10). We identified a downward trend in the number of sepsis admissions in the ICU after the opening of the PHDU. This may be due to the fact that resources are available to care for these patients in a PHDU, which has more staff, better routines and more advanced equipment than a general ward (4). The increase in the total number of admissions for sepsis in the PHDU is also greater than the decrease in the ICU. This is probably due to increased awareness both in Norway and internationally that children with suspected sepsis should be given high dependency care in order to clarify their diagnosis quicker and consequently provide better treatment (11).

Children with cancer have a higher risk of other serious diseases than their peers (12). We therefore grouped all children receiving cancer treatment into one diagnostic category. This explains why the number of admissions in this group is higher than in other reports (9, 13). The opening of the PHDU did not reduce the number of children with cancer in the ICU.

The PHDU functions as a step-down unit or a step-up unit depending on the child's need for high dependency care (1, 2). In the years following the opening of the PHDU, the number of transfers between this unit and the ICU increased. This may indicate that the interaction between the departments has improved and that the PHDU functions as an intermediate care unit. Optimised interaction enables the PHDU to help identify patients with a real need for intensive care and shortens the time they spend in the ICU.

One of the strengths of this study is the prospectively collected data, which includes all admissions since the opening of the PHDU at the Department of Paediatrics and Adolescent Medicine, Haukeland University Hospital, which is a hospital that receives a wide range of patients from a large geographical area.

One of the weaknesses of the study is that the unit is relatively new, and it is therefore too soon to make comparisons that require a longer observation period, as has been done in various ten-year reports (9). Furthermore, due to the COVID-19 pandemic, 2020 and 2021 are probably not completely representative years (8). In addition, the study is based on documentation from healthcare personnel treating patients, and errors in recorded information can therefore give a skewed picture.