Study design and setting
This prospective, multicentre cohort study was carried out over a period of 36months, from January 1, 2018, to December 31, 2020, in 5 perinatal medical centers in northern China, which are all level 3 neonatal intensive care units (NICUs) with high population density to better homogeneity. The 5 recruited hospitals volunteered to participate in QI initiative, including 4 general hospitals and 1 maternal and child health care hospital, with averages of 34 and 30 beds in the neonatology departments and NICUs, respectively. The NICUs of the hospitals received an average of about 3536 newborns per year, of which VLBW infants were about 123 cases (3.5%). The average ratio of nurses to bed and physician to nurse was about 1:1 and 1: 2, respectively.
Study was divided in two phases including pre-QI period (January 2018 to December 2018), and post-QI period (January 2019 to December 2020). In process of prospective data collection, the high incidence of AH was discovered in surprise for regular statistical analysis and month report of chart and graphics. We began to spend a lot of time on searching and reading literature, clinical studies and randomized controlled trials related to hypothermia to study and learn the physiological and pathological mechanism, adverse effects, prevalence and risk factors of hypothermia [1-4, 8-11,13-17,19-26]. By referring to scientific research methods from previous studies, we retrospectively investigated the temperature distribution and thermal insulation measures of 24 NICUs from northern China in 2017 to find out and distribution of AH and look into key drivers contributing to AH in processes including prenatal preparation, resuscitation, transport and post-entry into the NICU .
We assembled an interdisciplinary collaborative group named Hypothermia Clinical Research Group (HCRG) to develop initial bundle interventions by discussion and reading literatures and guidelines. The bundles were developed based on the medical literature review , the best practice recommendations of the California Perinatal Quality Care Collaborative (CPQCC) , the World Health Organization and the evidence-based principle of neonatal resuscitation projects [7,22-23].
Interventions were confirmed in December 31, 2018, and came into use in January 1, 2019. A multidisciplinary team composed of medical and nursing staff from neonatology, obstetrics, and anesthesiology were established to implement QI practices. During QI period, we used Plan-Do-Study-Act (PDSA) methodology to adjust or expand interventions carried out to decrease AH . We used the same digital laser infrared thermometer (OMRON, MC-347) for measurement in NICUs and made correction once a month to avoid errors. All the problems, suggestions, and temperature measurement videos were sent out to all participating centers by e-mail or WeChat discussion. Bundle emphasized accurate documentation of temperature at each point in time. All overall specific interventions were listed in Table 1(Placed at the end of the article). Monthly random onsite visits for executive leader were built to face-to-face communication for understanding barriers, requirement and supervising data quality. Regular in-service education and online lectures of videos of heat preservation were sent to public mailbox, which is acquired easily to help pediatric and obstetric providers and nurses strengthen awareness effectively and document temperature correctly.
The outline of sequential PDSA cycles to adjust or expand interventions during QI phase
Initial Bundles (January 1–March 31, 2019):
(1) Prenatal preparation (prenatal consultation, form multidisciplinary team, check materials);
(2)Set ambient temperature: Turn on the heating mode of the air conditioner and set the temperature above 25°C; set radiant warmers at 34℃
(3) Infant quickly dried after born;
(4) Pre-warmed hats made of stockinette or wool was placed on the head;
(5) Weighed after being placed in a pre-warmed blanket;
(6) Using chemical preheated mattress;
(7) Document temperature at key time point (10 min after birth, arriving at the NICU, soon after every 30 min, till temperature ≥ 36.5℃).
(8) Training and assessments on temperature measurement for nurses, making temperature measurement standard;
(9) Monthly charts reporting on hypothermia distribution and regularly quality control.
PDSA Cycle 1 (April 1–May 31, 2019):
Using polyethylene occlusive wrap infants without drying instead of drying infants immediately after birth.
PDSA Cycle 2 (June 1–August 31, 2019):
Introducing a heated transport incubator to keep warm in transportation.
PDSA Cycle 3 (September 1,2019 – March 31, 2020):
Revise admission hypothermia check list, adding individual signature blank area on check list to supervise effectively, and feedback checklist completeness at weekly meetings.
PDSA Cycle 4 (April 1– December 31, 2020):
Carrying out various online education lectures to medical staff and further emphasized the warmth link in the stabilization of Golden Hour for VLBW infants in NICUs by monthly online literature sharing learning.
The 4 cycles cover different links in the process of keeping warm, namely resuscitation, transportation, handover, and shared learning. In the process of resuscitation, especially for premature babies with small gestational age or small weight, the method of using plastic wrap to keep warm can better prevent the loss of water and heat through evaporation, radiation and convection. In addition to being economical, it can avoid the discomfort caused by the roughness of the repeatedly sterilized towel for wrapped child. Therefore, in order to better keep warm, we replaced the traditional method of wiping dry immediately after birth. Using polyethylene membrane with 30 cm × 40 cm size to wrap babies, which could allow infants’ head, torso and limbs be covered totally for better insulation [25-27].
In regular data feedbacks and interviews, we found great differences between different NICUs for transport warmth. Most units said they have not set special transport warmth part, but simply wrapped infants to the NICU. Transport distance varies with the actual situation of location between delivery room or operating room among units, some are on different floors of the same building, other are even in different buildings. To solve the problem, we introduced a heated transport incubator for transportation insulation in June 2019 [27-28], adding pre-transport preheating process in delivery room or operating room in bundle.
We found that the compliance of bundle declined in September 2019. The identified reasons of signal investigated by onsite visit were from insufficient staffing and inadequate force of supervision in handover. with relatively tense doctor-patient ratio in China, reducing turnover in staff is not feasible. To ensure the efficiency and feasibility of measures, the executive chairman of SNN suggested to revise the debriefing AH worklist for VLBW infants, adding signature blank to individual responsibility and feedback weekly according to local conditions in units. The changed version was tried on a small scale for 1 week for improved compliance, and was further promoted to all 5 perinatal medical centers. The revised paper version of worklist is listed as a member of necessary items. the list of prenatal necessary items is pasted on the side of the rescue box, as a warning to remind the pediatric consultation doctor to record the temperature in the delivery room in time. After being transferred to the NICU, the consultation staff fills in the general information and checks used thermal measures buttons in worklist, and then hand over it to the nurse on duty to complete the continuous measurement and recording work. Once worklist completed, it was clamped under the transparent plastic nurse work board. The next day the paper is retake by resident doctor, and feedback in every week meetings. The front and back patterns of the worklist paper were showed in Fig3-4.
During the fourth PDSA circle in March 2020, social factors such as social panic caused by epidemic situation, reduction of salary leading to the decrease of staff's work enthusiasm due to prevalence of Novel Coronavirus Epidemic. To rebuild awareness of hypothermia in medical staff, executive leader in SNN carried out various online education lectures to build up confidence and firm faith and further emphasized the warmth link in the stabilization of golden hour for VLBW infants by monthly online literature sharing learning and feedback meeting. In addition to emphasizing the compliance of measures, the meeting also emphasized the cooperation between obstetrics and pediatrics for prenatal communication, the cluster of management of medical operations, the standardized management of processes and the timeliness of feedback. We have added a link for prenatal consultation. Intrauterine consultation is carried out before delivery to carry out full communication between obstetrics and pediatrics. On the day of delivery, the consultation form is placed half an hour in advance and NICU is called at the same time to reserve sufficient time to reserve a transport incubator.
Hypothermia was defined as a rectal temperature of less than 36.5 °C, according to the WHO . Cold stress or mild hypothermia was defined as a temperature 36.0 °C to 36.4 °C, moderate hypothermia was defined as a temperature 32.0 °C to 35.9 °C, and severe hypothermia was defined as a temperature below 32 °C. Normothermia was defined as a body temperature between 36.5 °C to 37.5 °C. Redirection of intensive care was defined as limited care (not intensifying medical treatment) or withdrawal of care . Composite outcome included death before discharge or any of major morbidity including grade 3 or 4 IVH, grade 3 or 4 ROP and stage 2 or higher NEC (Bell et al) according to the Practice of Neonatology (5th Edition) . LOS was diagnosed by the clinical manifestations of systemic infection after 3 days of birth and abnormal values for 2 or more of the following non-specific infection indicators: WBC < 5 × 109 /L or WBC > 20 × 109 /L; C-reactive protein (CRP) ≥10 mg/L; platelets (PLTs) ≤100 × 109 /L; and procalcitonin (PCT) > 2 ng/ml . Moderate and severe BPD was defined as the requirement of any inspired fraction oxygen above 0.21 at the corrected GA of 36 weeks . If any fresh blood appears in the trachea intubation, with hematocrit dropping by more than 10% in the blood routine examination and the decrease of transmittance on the chest X-ray was diagnosed Pneumorrhagia .
The admission temperatures related data of VLBW infants were collected prospectively in SNN. The database provided maternal, delivery, neonatal clinical materials and temperature data before discharge, and the data were collected by a standardized operating procedure [5, 18, 34]. The admission temperature was defined as the infant’s rectal temperature measured at admission to the NICU within 1 h after birth, because it’s closer to core temperature . A worklist of temperature evaluation list for VLBW infants was used to carry on hand by the consulting physician before every intrapartum consultation to data collection, which documenting interventions on the back side and temperature data at different time points after birth on the front side in Fig.3-4.
Demographic data are expressed as medians and interquartile ranges (IQR). Categorical data are shown as percentages. Comparison of clinical characteristics between groups was calculated with the Mann-Whitney U-test and Chi-square test. Risks of outcomes were compared between groups were tested in a bivariate analysis, followed by a logistic regression analysis. P < 0.05 was considered statistically significant. The statistical analyses were conducted using SPSS v. 26.0 (SPSS Inc., Chicago, Illinois) and QI Macros 2018.09 (Denver, CO). Special cause signals were identified by using standard control chart rules .