The infant and toddler periods are vital times for gross motor development in humans. Gross motor behavior is one of the earliest directly observable elements of adaptive function. At 12 months old, children begin learning to walk, and their functional motor connectivity is correlated with walking. During the toddler years, children change quickly in their motor function and physical growth, and their motor skills and ability to explore their environment improve. Therefore, at this stage, factors such as diseases, environment and nutrition, interfere with the chances of infants and young children receiving external information, which affects their motor development. Uzark et al. found that gross motor impairments were common in infants after cardiac operations. Friedman et al. showed that young (aged 1–3 years) congenital diaphragmatic hernia survivors continued to have a high incidence of motor and language problems. Although motor developmental dysfunction presents in these populations, the motor developmental function levels of children in the PICU remain unclear. In addition, children in PICUs are more critically ill, undergo more invasive procedures, and receive more drugs; therefore, the level of motor developmental function in these infants and toddlers deserves attention. Unfortunately, few studies have focused on infants and toddlers in PICUs. This study was the first to assess gross motor developmental function in PICU survivors.
In this study, the incidence of gross motor developmental dysfunction was 68.6%. This statistic is higher than that reported for children after cardiac surgery (incidence 21–64%) [30, 32]. The incidence of motor dysfunction was 60% in infants who survived congenital diaphragmatic hernia repair , possibly because of the longer mechanical ventilation time, ICU stay, and more complications in infants and toddlers in the PICU compared with those with post-cardiac surgery. We believe that for critically ill children aged 1 month to 3 years, assessing gross motor developmental function is more important in guiding subsequent rehabilitation.
We also found that IMV days were significantly longer in the dysfunctional group than in the non- dysfunctional group. This suggests that the length of IMV is related to the occurrence of gross motor developmental dysfunction. IMV is one of the most commonly used treatment methods in PICUs, but it causes many dysfunctions in motor skills, cognition and psychology despite saving the lives of critically ill children. At present, many studies in adults have shown that IMV is a high-risk factor for ICU-acquired weakness (AW) [33, 34]. Patel et al. found that patients with ICU-AW had significantly longer mechanical ventilation times. A systematic review of published work showed evidence of ICU-AW in 46% (95% confidence interval [CI] 43–49%) of adult ICU patients who experienced lengthy mechanical ventilation, sepsis, or multiorgan failure. However, the effects of mechanical ventilation on infants' gross motor developmental levels remain unreported. Our research showed that IMV days were associated with infants' gross motor developmental dysfunction. IMV is also accompanied by longer PICU stays, more sedative use, more severe protopathic conditions and more invasive examinations. Length of PICU stay, days on sedatives, and days using CRRT were longer, and the vasoactive drug use rate, sepsis incidence and PCIS scores were higher in the dysfunctional group than in the non-dysfunctional group. These factors may promote gross motor developmental dysfunction in children.
Our research showed that the above factors were linearly correlated with GMQ, and the degree of gross motor dysfunction was significantly negatively correlated with PICU stay, sedative use and CRRT days and positively associated with PCIS scores. The GMQ of septic patients was also significantly lower than that of aseptic patients. To further analyze the independent risk factors that lead to gross motor developmental dysfunction, we performed a linear regression analysis of the above factors. The results showed that IMV days, sepsis and PCIS are independent risk factors for gross motor developmental dysfunction in PICU infants and toddlers. This is consistent with the results of an adult study on ICU-AW. Jongheet al. conducted a multicenter, prospective study that showed that physical dysfunction in ICU patients was associated with prolonged mechanical ventilation. A prospective cohort study by Borges et al. indicated that physical activity, exercise capacity, and muscle strength were significantly reduced in ICU sepsis survivors, even at 3 months after discharge. A meta-analysis conducted by Yang et al. incorporating 14 studies, showed that sepsis (OR, 2.2; 95%CI, 1.30–3.71) and duration of IMV (OR, 1.1; 95%CI, 1.00–1.22) were significantly associated with ICU-AW. A multicenter study by Choong et al. suggested that Pediatric Risk of Mortality III (PRISM III) is an independent risk factor of social/cognitive dysfunction.
To investigate the independent risk factors for gross motor dysfunction in infants and Toddlers, we used a multivariate linear regression analysis. The result showed that IMV days, sepsis and PCIS were independent risk factors for gross motor developmental dysfunction. This is similar to the results of several adult studies[41, 42]. We believe that the above risk factors leading to children's gross motor developmental dysfunction may have three pathways: 1. Prolonged mechanical ventilation and sepsis can lead to limb muscle atrophy[43, 44], resulting in weakened muscle strength in children; thus, abnormal assessment results may be due to weakened muscle strength; 2. Studies have confirmed that sepsis and IMV can cause brain dysfunction[45, 46]. However, the central nervous systems of infants and young children remain in the developmental stage, and motor neuron integrity is crucial to children's mastering their motor skills. Therefore, damage to the child's motor center due to sepsis and IMV days may affect the overall motor developmental level. 3. Impairment of cognitive function is related to motor developmental dysfunction, and previous studies have confirmed the effects of sepsis and mechanical ventilation on cognitive function[43, 47, 48]. Impaired cognitive function factors can affect motor function in children, especially infants[49, 50]. Whether this phenomenon exists in infantile and toddler PICU survivors requires further study.
This study had several limitations. First, the study was an observational study with a small sample size. Therefore, we found that only IMV days, sepsis and PCIS differed statistically when performing linear regression analyses on related factors. Previous studies showed that hormone and sedative use were significantly associated with the occurrence of physical dysfunction in pediatric and adult patients[51-53]. This study yielded inconsistent results; Therefore, more samples should be included for further analysis. Second, two assessment methods were used to assess the same patient pre-PICU and post-PICU. Due to the children’s pre-admission GMQs were unavailable, only the ASQ-3 questionnaire could be used to indirectly reflect gross motor function. Third, our study only assessed the participants’ motor development, while infant and toddler PICU survivors may have other developmental impairments such as cognitive, speech, psychological, and emotional disorders. Whether these dysfunctions are related to motor dysfunction warrants further study. Finally, we did not follow-up the enrollees to observe their gross motor function after discharge. In the next study, we will further follow this.
In conclusion, this study showed that gross motor developmental dysfunction in infantile and toddler PICU survivors are more common and may be exacerbated by experiences associated with longer IMV days and increasing illness severity combined with sepsis.
We suggest that early rehabilitative intervention in these children’s gross motor developmental function may reduce physical morbidity. Furthermore, detailed comprehensive investigations of developmental functions, including gross motor, fine motor, language, cognition and social abilities, are warranted.