Clinical profile of mechanically ventilated children aged 1 month to 18 years

Introduction

Most of the critically ill children are managed in Pediatric Intensive Care unit (PICU) with the aim of achieving a better outcome^[1] and around 20-64% require mechanical ventilation (MV) at some point during their PICU stay.^[2], ^[3] MV is a life supporting device to maintain the respiratory physiological function at the time of acute respiratory failure.^[4], ^[5] Though MV has lifesaving benefits, it can result in several complications and adverse physiologic effects which may prolong the duration of MV itself, duration of hospitalization and may increase patient mortality.^[6]

Also, many of the times, lots of errors can happen during MV and the possible reasons could be either due to scarcity of the resources, inexperianced doctors and nursing staff, lack of specific hospital protocols or severe disease itself which may prolong duration of MV. A lot of studies about MV in children are available from western world while very limited data from India. Also no studies are done from our region, Kolhapur where most of the patients come from surrounding rural area for critical care management. Hence this study was carried out with the aim of to study clinical profile of mechanically ventilated children aged 1 month to 18 years in PICU of D.Y.Patil Medical college and hospital, Kolhapur.

Materials and Methods

This retrospective study was conducted among 103 children aged 1 month to 18 years of age over the period of 5 years between 1^st May 2014 to 30^st April 2019. Ethical clearance was obtained from Institutional Ethics Committee (DYPMCK/247/2019/IEC). All children who were admitted in PICU of D.Y.Patil Medical college and hospital, Kolhapur and who required MV were included in this study. Surgical causes like operated congenital defects, head injury and road traffic accidents who required MV were excluded from this study.

The medical records like PICU Register and case sheet of mechanically ventilated children were reviewed after taking the permission from hospital authorities and was recorded in a standard proforma. It included the following information on demographic details like age and gender, date of admission, associated comorbid conditions, preliminary clinical diagnosis on the basis of presenting complaints, clinical signs and investigations, indications of intubation and mechanical ventilation, date of initiating ventilation, length of MV, mode of ventilation, complications of MV like laryngeal edema, ventilator associated pneumonia (VAP), atelectasis and pneumothorax, accidental extubation etc. and duration of hospital stay. VAP was defined as when ventilation greater than 48 hours with a new and persistent infiltrate, consolidation on chest radiograph and at least 3 of following: fever, leucopenia or leukocytosis, purulent sputum, rales, cough or worsening gas exchange.^[7] Atelectasis was identified by clinical and radiological examination while laryngeal edema was present if stridor occurred within 2 hours of extubation. ^[8] The outcome of the child was also recorded as either extubated and improved, died on the ventilator or discharged against medical advice. The indications of intubation and MV were divided systematically as follows:

Results

A total 1348 patients were admitted to our PICU during the study period and among them 103 (13.08%) patients required MV. Out of 103 patients, 53 (51.46%) and 50 (48.54%) were males and females respectively with male : female ratio was 1:0.94. Fifty six (54.37%) patients were under-five age group who required MV. The age group variables who needed MV is shown in [Table 1].

The preliminary diagnosis on admission of patients who needed MV were respiratory 42(40.78%) followed by neurological 29(28.15%), miscellaneous 22(21.35%) and cardiac 10 (9.70%) illnesses. ([Table 2]) Among respiratory and neurological illnesses, pneumonia and status epilepticus were the commonest causes. The co-morbid conditions like anemia 16(15.53%), malnutrition 12(11.65%), Epilepsy 7(6.8%) and cerebral palsy 2(1.94%) were also present.

The indications for intubation and MV were highest with respiratory failure 31(30.09%), followed by cardiorespiratory failure23(22.33%). The indications for intubation and MV are shown in [Table 3].

All patients were ventilated with pressure support modes either Synchronized Intermittent Mandatory Ventilation (SIMV) or with Pressure Control(PC) depending upon the severity of illness. Out of 103 patients, 65(63.10%) and 38(36.90%) ventilated with SIMV and PC modes respectively.

Also, the median duration of MV was 3 days and maximum patients 65(63.10%) reside in MV for ≥1-3 days. ([Figure 1]) The median duration of hospital stay was 6 days in MV patients.

A total number of complications occurred in MV patients were 44(42.72%) out of total 103 patients. The laryngeal edema with stridor 20(19.42%) was the commonest complication post-extubation while endotracheal tube blockage 08(07.77%) was the commonest complication during ventilation. VAP was observed in only 2(01.94%) patients and was caused by Klebsiella pneumoniae. Distribution of complications occurred in patients during MV and post extubation is shown in [Table 4].

The immediate outcome of patients who needed MV was highest in improved and discharged 60(58.25%) catogary while death occurred in 38(36.89%) The outcome of MV patients is shown in [Table 5].

The highest number of deaths 9(23.68%) occurred in sepsis followed by 8(21.05%) pneumonia patients. A significant correlation (p=0.02) was found between death on MV with comorbid conditions like malnutrition, anemia and cerebral palsy.

Discussion

The incidence of MV in PICU varies from 14-60% in different parts of the country. In our study, 13.08% (103/1348) critically ill children received MV. Similar incidence of 15.93% and 9.11% was observed by Bhori NS et al^[2] and Hatti S et al^[3] respectively. The incidence of MV was less in our study as compared to study done by Vijaykumary et al^[6] (52%) from Srilanka. Khemani et al^[1] from united states observed 30% of children admitted to PICU were received MV. The factors behind this wide variation in the incidence of MV could be probably because of severity of illness, experience and knowledge of treating physician and infrastructure of PICU. 54.37% patients were under-five years of age who required MV from our study as compared to mean age was 1±0.8 years in a study done by Hatti S et al.^[3] Also, the male : female ratio was 1:0.94 in our study as compared to 1.25:1 and 1.03:1 from studies done by Bhori NS et al^[2] and Hatti S et al^[3] respectively.

The initial clinical diagnosis was divided into respiratory, neurological, cardiac and miscellaneous causes. Among respiratory causes pneumonia (25.24%), while status epilepticus (10.68%), congenital heart disease (04.85%) and sepsis (14.57%) were the commonest causes from neurological, cardiac and miscellaneous respectively. A study done by Hatti S et al^[3] observed meningitis (15.7%) among neurological cause, pneumonia (16.3%) among respiratory, congenital heart disease (9.9%) among cardiac and 29% from miscellaneous causes. The most common indication for intubation and MV in our study was respiratory failure (30.09%) due to affection of respiratory system, followed by cardiorespiratory failure (22.33%). Similar observations were noticed in studies done by Bhori NS et al,^[2] Farias JA et al,^[9] Harel Y et al,^[10] and Kendirli T et al.^[11] Studies done by Hatti S et al,^[3] Wolfler A et al^[12] and Mukhtar B et al^[13] observed acute neurological cause as the most common indication for MV.

The choice of mode for MV was SIMV (63.10%) followed by PC (36.9%). Pressure control mode of MV was also having high mortality probably because of more severe illness and need rest to the respiratory muscles. A similar finding was observed by Bhori NS et al.^[2]

Also, we found the median duration of MV was 3 days and maximum patients (63.10%) reside in MV for ≥1-3 days similar to study done by Hatti S et al^[3] and Mukhtar et al.^[13] Bhori NS et al,^[2] Farias et al^[9] and Wolfler et al ^[12] observed the mean duration of 4-6 days. Kendrili T et al^[11] observed the period of MV in their study to be 18.8±14.1 days. The median duration of hospital stay was 6 days in MV patients while Bhori NS et al ^[2] observed the mean duration of hospital stay was 11.89±12.80days. The patients who developed complications on MV had longer duration of hospital stay.

In the present study, the complication rate was 42.72% while Bhori NS et al^[2] found 33.33% and reported atelectasis and laryngeal edema with post extubation stridor was the commonest complication. Similarly, we also found post extubation stridor in 19.42% patients. We also reported endotracheal tube blockage (07.77%), pneumothorax (05.82%) and accidental extubation (03.88%) which could have been prevented by continuous monitoring of the patient. Surprisingly, we observed VAP only in 01.94% patients as compared to 05.56% and 11% by Bhori Ns et al ^[2] and Vijaykumary et al^[6] respectively

In our study we found the mortality rate of 36.89% with age related mortality was more in infants (28.94%). Various studies from developing countries reported variable age and mortality rate. Studies conducted by Bhori N et al^[2] Kendirli T et al^[11] and Shakut et al ^[14] found almost similar mortality rate of 31.7%, 37% and 38.89% from Turkey, Pakistan and India respectively. Vijaykumary T et al^[6] found 27.6% mortality rate with highest in children above 5 years of age. Hatti S et al^[3] found significantly high 65.4% mortality rate and attributed to lack of respiratory therapist, lack of education and training of MV as well as delayed presentation with multiorgan dysfunction syndrome and severity of illnesses. Studies from developed countries found the mortality rate of less than 2%. To improve the outcome of MV children we should conduct continuous medical educational program for physicians and nursing staff to train about MV.

Our study has certain limitations. Firstly, this study is a retrospective and outcome of MV depends on infrastructure of PICU along with expertization of treating doctors and nurses so the study findings may not be generalized to other PICUs. Secondly MV has undergone continuous evolution in an attempt to reduce complications and mortality in patients. But, still our study helps to identify early indications of MV, to prevent iatrogenic complications and to improve the outcome of MV.

Conclusions

The incidence of MV in our PICU was 13.08% and the high number of patients were under-five years of age. The preliminary diagnosis of patients who needed MV was mainly respiratory (Pneumonia) and neurological (Status Epilepticus) illnesses while the indication for intubation and MV was either respiratory or cardiorespiratory failure. Post extubation laryngeal edema and endotracheal tube blockage during MV were the commonest complications occurred. The maximum number of patients were improved and discharged who were on MV while the deaths occurred mainly in sepsis and pneumonia patients.

Conflict of Interest

None.

Source of Funding

None.