a b s t r a c t

Objectives: The purpose of this study is to determine if stable, well-appearing, drowning patients who have nor- mal age-adjusted vital signs and pulse oximetry upon arrival to the emergency department may be safely discharged without a prolonged observation period.

Methods: Medical records were retrospectively reviewed for drowning patients presenting to a single pediatric emergency department from 1995 to 2014. Data were collected on vital signs and pulse oximetry at presentation, chest x-ray results, disposition and complications for each encounter. Patients were identified as having either normal or abnormal initial vital signs and pulse oximetry, and were compared based on disposition and compli- cation rates.

Results: Two hundred seventy-six records were initially evaluated and 91 were excluded. Thirty-six percent had normal age-adjusted vital signs upon arrival. Patients with abnormal temperature, respiratory rate or pulse ox- imetry, as well as those with any abnormal initial cardiopulmonary Physical exam findings, abnormal mental sta- tus, or chest radiograph findings, were more likely to be admitted to the hospital. Eight patients developed Respiratory complications after presentation to the emergency department. Those with abnormal pulse oximetry readings on arrival were more likely to develop complications. Only two patients who developed complications had initially normal vital signs and each had evidence of clinical deterioration within 1 h of arrival.

Conclusions: The overall complication rate in initially stable, well-appearing drowning patients is low. An abnor- mal pulse oximetry reading at presentation may help predict subsequent complications. Those patients with nor- mal age-adjusted vital signs and physical exam at presentation may not require a prolonged observation period.

(C) 2018

Introduction

Drowning continues to be a significant cause of morbidity and mor- tality worldwide. In the United States, unintentional injury is the lead- ing cause of death in children 1-18 years of age [1,2] with drowning being the leading cause of unintentional injury deaths in children 1-4 years old, and the second leading cause of unintentional injury deaths in children ages 5-14 years [1]. In 2014, there were 822 deaths in the United States due to drowning in children 0-18 years of age [1]. Efforts aimed at drowning prevention and providing early, on-scene, bystander resuscitation have likely contributed to the substantial de- creases in mortality secondary to drowning events in the past decade [3,4]. However, despite this overall decline in the number of drowning events, it remains a significant cause of pediatric morbidity and mortal- ity. Additionally, drowning events continue to be a significant cost to the

* Corresponding author at: Children’s Hospital Los Angeles, Keck School of Medicine/ University of Southern California, Division of Emergency and Transport Medicine, 4650 Sunset Blvd. MS#113, Los Angeles, CA 90027, United States.

E-mail address: [email protected] (C.E. Brennan).

healthcare system. In 2014 there were a total of 7701 reported uninten- tional pediatric drowning injuries in the United States, and 3796 pediat- ric patients were hospitalized with an average admission cost of

$31,137 [1]. The total healthcare dollars spent on drowning admissions that year was $118,204,000 [1].

Following a drowning event, many patients present to the emer- gency department in unstable or critical condition. However, some patients may present with only mild symptoms and some may be asymptomatic. Much of the previous drowning literature has focused on patients presenting with severe symptoms requiring inpatient or critical care. However, there is limited literature addressing the disposi- tion of well-appearing, asymptomatic drowning victims.

Historically, it has been suggested that all drowning patients require admission due to concern that an initially stable drowning patient may show signs of respiratory deterioration such as respiratory distress, hyp- oxemia, ARDS, acute respiratory failure, or respiratory arrest several hours after the initial event [5,6]. Subsequent studies show that most patients with respiratory deterioration can be identified within 4-8h after the event [7-9]. Therefore, much of the more recent literature sug- gests prompt ED evaluation and management in non-ill drowning

https://doi.org/10.1016/j.ajem.2018.01.050

0735-6757/(C) 2018

patients, followed by a period of observation in the emergency depart- ment, may be sufficient to safely discharge drowning patients [7-10].

The aim of this study was to determine if pediatric drowning pa- tients who are well-appearing with normal age-adjusted vital signs and pulse oximetry at presentation to the emergency department can be safely discharged without admission or a prolonged observation period.

Methods

Study setting and patient population

We conducted a retrospective review of all medical charts of pediat- ric patients presenting to a single, urban, tertiary care pediatric emer- gency department from 1995 to 2014, with a diagnosis of drowning, near-drowning, or Submersion injury, as the coding definition evolved over time. This study was approved by the institutional review board of our medical center. Patients were included if they were ages 0-18 years and were initially evaluated in the emergency department for drowning events. Those patients who were transferred from other institutions or who were stabilized in our emergency department and then transferred to another institution were excluded. Additional exclu- sion criteria included patients with significant pre-existing medical problems (severe cardiac, pulmonary or neurologic diseases), patients with significant distracting injuries upon presentation, those patients with an initial Glasgow Coma Scale score of b14, patients presenting after an out of hospital cardiac arrest, and any patient requiring critical care interventions in the emergency department (e.g. endotracheal in- tubation, cardiopulmonary resuscitation, vasopressors, thoracostomy).

Definitions

Normal age-adjusted pediatric heart rate, respiratory rate, and blood pressure values were adopted from the Advanced Pediatric Life Support (APLS) guidelines [11]. Temperature was considered normal if between 36 and 38 ?C. Pulse oximetry was generally monitored continuously using transcutaneous probes placed over a single digit, and pulse oxim- etry values at varioUS time points were recorded in the medical chart. A normal pulse oximetry value was defined as greater than or equal to 95%. “Initial vital signs” was defined as the first set of temperature, heart rate, blood pressure, respiratory rate, and pulse oximetry values taken upon the patient’s arrival to the emergency department. Patients were considered to have developed a complication if they had any evi- dence of respiratory distress or failure, alteration in mental status, aspi- ration events, or death after presentation to the emergency department.

Data collection

We performed a single-center retrospective chart review of patients evaluated between July 1, 1995 and April 30, 2014 at an urban, level-one pediatric trauma center and Tertiary care children’s hospital in Southern California. Patients were identified by the ICD-9 codes for discharge di- agnoses. The diagnoses of drowning, near-drowning and submersion injury were included.

Data were collected on a standardized data sheet by a single re- viewer and entered into a Research Electronic Data Capture (RedCap) database [12]. Gender, age, site of drowning, Method of arrival, and his- torical variables including submersion time, apneic time and resuscita- tion times, if available were recorded. Vital signs and pulse oximetry values upon arrival were also recorded. Initial respiratory examination, mental status and Skin color findings were recorded, and any signs of distress such as retractions were noted. If a chest radiograph was per- formed, the emergency department attending physician interpretation, and/or the attending radiologist‘s final interpretation was recorded. If a patient was discharged home from the emergency department, the patient’s records were reviewed to determine if any return visits

occurred within three days after the drowning encounter. For those ad- mitted to the hospital, any complications, as previously defined, were recorded.

Data analysis

The statistical package for the Social Sciences (SPSS Version 24, SPSS Inc., Chicago, IL, 2016) was used for statistical analyses. Descriptive sta- tistics were used to summarize patient demographics. A Point bi-serial correlation was done to determine the relationship between continuous variables and disposition. Categorical variables were analyzed using Pearson Chi-Square test. All tests were 2-sided with a Type I error rate of 0.05, and p value of b0.05 was considered statistically significant.

Results

A total of 276 drowning patients were identified, from which 91 were excluded. The most common reasons for exclusion were patients presenting with a GCS of b14, those requiring critical care upon arrival, or patients who did not have their entire care for the encounter at this single institution. A total of 185 charts were fully reviewed, but 5 addi- tional patients were excluded due to missing data. One hundred eighty patients were included in the analysis.

The mean age for all patients included in the study was 2.94 years (SD = 2.73 years). Thirty-six percent of patients were females and 64% were males. All drowning episodes occurred in non-frigid, fresh water environments. Most episodes occurred in a swimming pool (71%), with other sites including bathtub (16%), hot tub (8%), lake (3%) and bucket of water (2%). The majority of patients arrived by heli- copter (63%). Of the remaining patients, 24% arrived by ambulance, 7% arrived by private vehicle, and the method of arrival was unknown in 6% of patients. Submersion time was unknown in several cases (33.9%), but was less than five minutes in the remaining cases (66.1%). It is unknown if there was a period of apneic time in the majority of cases (64.4%). resuscitation time, if required, was less than five minutes in cases which this information was available (63.3%) (Table 1). There was no statistically significant correlation between age, submersion time, apneic time, resuscitation time, and disposition to admission or discharge.

Sixty-two (34%) patients had normal age-adjusted initial vital signs and pulse oximetry upon presentation to the emergency department. Patients with any Abnormal vital signs or pulse oximetry at time of tri- age showed statistically significant higher admission rates (p b .001).

Table 1

Submersion, apnea and resuscitation times.

Characteristic	Frequency
	n (%)
Submersion time b30 s	35 (19.4%)
b60 s	34 (18.9%)
1-2 min	24 (13.3%)
2-3 min	9 (5.0%)
3-5 min	17 (9.4%)
Unknown	61 (33.9%)
Apneic time None	47 (26.1%)
b30 s	6 (3.3%)
b60 s	8 (4.4%)
b2 min	3 (1.7%)
Unknown	116 (64.4%)
Resuscitation time None	54 (30%)
b1 min	43 (23.9%)
1-3 min	10 (5.6%)
3-5 min	7 (3.0%)
Unknown	66 (36.7%)

Table 2

Patient characteristics and disposition from ED.

Feature Disposition p value

Of the patients who were discharged from the emergency depart- ment, only 2 had a return visit within 3 days. Both patients had normal vital signs and physical examinations at time of initial presentation after

Home (n=)

Sex Male	56 (48.3%)	60 (51.7%)	.879	departmen treatment.
Female	31 (47%)	35 (53%)	.879

Admission (n=)

the drowning event, and neither patient had Abnormal chest radiograph findings. In both cases, the patient was discharged from the emergency t on the day of the return visit without need for additional

Abnormal initial vital signs 44 (71%) 18 (29%) b.001

Temperature	14 (33.3%)	28 (66.7%)	.035
Heart rate	17 (41.5)	24 (58.5%)	.378
Respiratory rate	16 (34.8%)	30 (65.2%)	.042
Blood pressure	7 (38.9%)	11 (61.1%)	.464
Pulse oximetry	9 (15.8%)	48 (84.2%)	b.001
Abnormal physical exam	69 (60.5%)	45(39.5%)	b.001
Cardiopulmonary	7 (20%)	28 (80%)	b.001
Mental status	2 (16.7%)	10 (83.3%)	.035
Abnormal chest radiograph	24 (30.8%)	54 (69.2%)	b.001

When isolating each age-adjusted vital sign and pulse oximetry, this was also true for patients with abnormal temperature, respiratory rate, and pulse oximetry at presentation. There was no significant difference in admission rates when isolating initial heart rate and blood pressure (Table 2). Patients with an abnormal cardiopulmonary examination or mental status at time of presentation were also more likely to be admitted (Table 2).

Chest radiographs were performed in 159/180 (88%) patients. Of these, 78 were found to have an infiltrate, with chest radiograph inter- pretation either by the attending emergency department physician and/or the attending radiologist. Those with any abnormal findings had a significantly higher rate of admission (p b .001) (Table 2). In the 54 patients with an abnormal chest radiograph who were admitted, 4 had evidence of respiratory deterioration after presentation. None of these patients required any critical care interventions and escalation of care was limited to supplemental oxygen only.

More than half (52%) of the patients included in this study were ad- mitted to the hospital from the emergency department. Of these pa- tients, 8 patients had deterioration in respiratory status after presentation (Table 3). There were no other complications noted. The presence of abnormal vital signs at presentation was not significantly associated with the development of complications. However, when iso- lating the pulse oximetry reading, those who developed complications were significantly more likely to have an abnormal pulse oximetry read- ing upon presentation (p = .001) There was no difference in initial physical examination or chest radiograph findings (Table 4). Only two of the patients who developed complications had entirely normal age- adjusted vital signs at presentation. However, both of the two patients with initially normal vital signs were found to be intermittently grunting within 1 h of presentation, and one of the patients also had an abnormal initial examination and chest radiograph findings. No pa- tients who developed complications after presentation required inter- ventions other than supplemental oxygen, and all returned to baseline prior to discharge from the Inpatient unit.

Discussion

This is the largest and most recent study focusing on discharge of pe- diatric drowning patients from the emergency department. Addition- ally, this is the first pediatric drowning study to use age-adjusted vital signs and pulse oximetry as part of criteria for early discharge. In our study, we found relatively few cases of clinical deterioration in initially well-appearing drowning patients. All but two of the 8 patients who de- veloped complications had some abnormal age-adjusted vital signs upon presentation, and only one of these two patients also had normal physical examination findings from the time of presentation. The one patient with normal initial vital signs and physical exam findings upon presentation had a change in clinical status and was found to have inter- mittent grunting respirations within 1 h of presentation. Only an abnor- mal initial pulse oximetry reading was significantly associated with subsequent clinical deterioration (p = .001). In well-appearing patients presenting to an emergency department following a drowning episode, initial vital signs and pulse oximetry or re-assessments within the first hour of presentation, are likely to identify patients with complications. Only 34% of patients in our study had normal age-adjusted vital signs upon presentation. This may have been due to factors independent of true cardiopulmonary impairment since the majority of these patients had no additional complications. EMS personnel transported most of these patients, and therefore patient fear or anxiety may have contrib- uted to the common findings of hypertension and tachycardia. For this reason, vital signs and pulse oximetry were each analyzed separately. Pulse oximetry is independent of age or anxiety related factors and therefore may better represent a patient’s cardiorespiratory status.

When isolated in this study, an abnormal pulse oximetry reading upon arrival was associated with clinical deterioration.

Despite the low number of patients with clinical deterioration, our study showed that more than half of the patients initially presenting to the emergency department following a drowning event were admit- ted to the hospital. Factors associated with admission in our study in- cluded an abnormal initial temperature, respiratory rate or pulse oximetry, as well as any abnormal initial physical exam findings or an abnormal chest radiograph reading. Although there is not a direct asso- ciation with severity of clinical course, admission may be seen as a proxy for perceived severity of drowning cases in this study.

In 1996, Noonan, et al., conducted a retrospective review of 72 pedi- atric patients with fresh water drowning events. The mean age of pa- tients in the study was 2.5 years, which is similar in age to the patients in our study. They found that in patients with a normal physical examination at presentation, those who later developed abnormal physical exam findings did so within 7 h. In all but one case, these

Table 3

Characteristics of patients with clinical deterioration after presentation to the emergency department.

Patient	Age	Sex	Site of drowning	Initial vital signs	Initial cardiopulmonary exam	Initial mental status	Chest radiograph findings	Complication
1	8 mos	F	Bathtub	Normal	Normal	Normal	None	Intermittent grunting w/in 1 h
2	9 mos	M	Bathtub	Normal	Abnormal	Normal	Bilateral infiltrates	Grunting w/in 1 h
3	17 mos	M	Pool	Abnormal	Normal	Normal	Right sided infiltrate	Tachypnea at 26 min after arrival
4	4 yrs	M	Pool	Abnormal	Normal	Normal	None	Hypoxemia requiring oxygen w/in 1 h
5	24 mos	F	Pool	Abnormal	Abnormal	Normal	Bilateral infiltrates	Hypoxemia requiring oxygen w/in 1 h
6	8 mos	M	Bathtub	Abnormal	Abnormal	Normal	Perihilar	Grunting w/in 1 h
7	6 yrs	M	Pool	Abnormal	Abnormal	Normal	Bilateral infiltrates	Grunting w/in 1 h
8	5 yrs	M	Pool	Abnormal	Normal	Normal	None	Increased oxygen requirement w/in 1 h

Table 4

Clinical features and development of complications

Feature Complications p value

had a return visit within three days, we cannot determine if any discharged patients presented to other institutions due to clinical dete- rioration. Data regarding submersion, apneic and resuscitation times

Yes

(n = 8)

No

(n = 172)

were missing in several cases. Therefore, it could not be determined whether there was an association between these variables and the de-

Abnormal initial VS 2 (3.2%) 60 (96.8%) .564

Temperature	1 (2.4%)	41 (97.6%)	.578
Heart rate	2 (4.9%)	39 (95.1%)	.381
Respiratory rate	2 (4.3%)	44 (95.7%)	.264
Blood pressure	0 (0%)	18 (100%)	.637
Pulse oximetry	5 (8.8%)	52 (91.2%)	.001
Abnormal physical exam	4 (3.5%)	110 (96.5%)	.607
Cardiopulmonary	4 (11.4%)	31 (88.6%)	.053
Mental status	0 (0%)	12 (100%)	.329
Abnormal chest radiograph-ED read	4 (6.9%)	54 (93.1%)	.053
Abnormal chest radiograph-radiology read	3 (5.1%)	56 (94.9%)	.162

findings were present within 4.5 h. This study concluded that patients should be observed for 6-8 h after presentation in order to detect any clinical deterioration. Two key differences in this study when compared to this current study, is that they broadly defined tachypnea as N30 breaths per minute for all ages and pulse oximetry values were not described for any patient. Therefore, the number of patients with true cardiopulmonary deterioration may have been inaccurately repre- sented. In our study, we adjusted for age-related normal respiratory rates to more accurately identify tachypnea, and we incorporated pulse oximetry as a variable.

A later study by Causey, et al. in 2000 examined 48 pediatric drown- ing patients presenting to an emergency department and stratified them by severity based upon Oxygen administration and length of stay. They identified 3 patients with a GCS of 14 or 15 who developed respiratory deterioration within 4 h of their arrival to the ED. They rec- ommended an observation of 4 to 8 h in the ED. However, a large per- centage of patients were transferred from outside hospitals, many of whom initial vital signs at presentation were not available. In our large single-center study, we eliminated patients who were transferred from other institutions to help control for potential confounders and to Declaration of interest“>account for variability in how vital signs are recorded at various institu- tions. Additionally, the timing of first recorded vital signs at the study hospital varied up to 6 h after presentation. In our study, all initial vital signs were recorded within 1 h of arrival to the emergency depart- ment and were often recorded immediately upon arrival. Similar to the results of our study, the 9 patients in this study who required supple- mental oxygen for any period had lower average oxygen saturations at presentation. No patient who had normal oxygen saturation upon ad- mission had a subsequent clinical deterioration.

The current standard of care based on prior studies is a 4-8h obser- vation period [7-10]. Using specific age-adjusted vital signs and contin- uous pulse oximetry, more clinical information is available than in past studies. We found that those who had abnormal age adjusted tempera- ture, respiratory rate or pulse oximetry were significantly more likely to be admitted. In the few patients who developed complications, only two patients had normal age-adjusted vital signs and these patients devel- oped complications within 1 h of presentation.

Limitations

There are several limitations to this study. Patients were identified by ICD-9 discharge diagnosis. Therefore, it is possible that some patients may have been missed if the discharge diagnosis was not coded as drowning, near-drowning, or submersion injury. However, these are standard Diagnosis codes, so missing many patients is unlikely. Given the retrospective nature of the review, follow up of these patients could not be recorded. We did, however, review the entire medical re- cord of all discharged patients to identify any return emergency depart- ment visits within three days of discharge. Although only two patients

velopment of complications. This was a single-center study conducted at an institution in Southern California and was therefore limited to the geographic catchment area as well as the patient demographics of the institution. Nevertheless, this is the largest retrospective study of pediatric drowning patients, and excludes Transferred patients. All epi- sodes occurred in a non-frigid, freshwater environment and therefore the results of our study may not be applicable to drowning events that occur in frigid or saltwater environments. Incorporation of end tidal car- bon dioxide monitoring may be useful in the evaluation of these pa- tients, and future studies could incorporate this. Finally, there were few episodes of clinical deterioration in initially well-appearing pediat- ric drowning patients, so additional studies are needed to support re- sults of this study.

Conclusion

Normal initial age-adjusted vital signs and physical exam in stable, well-appearing drowning patients cannot exclude the possibility of complications. However, complications in initially well-appearing pedi- atric drowning patients are rare. In this study we found that in patients with initially normal age-adjusted vital signs and pulse oximetry who subsequently developed complications did so within 1 h of presentation to the emergency department. All but two patients with complications had some abnormal vital signs from presentation. Those patients with abnormal initial pulse oximetry readings were significantly associated with subsequent clinical deterioration. Therefore, pulse oximetry is a useful tool in deciding which patients require admission. In all cases, close vital sign monitoring in addition to physical examination, detected clinical deterioration within a 1 h observation period. This suggests that a prolonged observation period may not be necessary. Additional pro- spective and multi-center studies are needed to make further conclusions.

Declaration of interest

The authors of this study have no actual or potential conflict of inter- est to declare that could inappropriately influence, or be perceived to in- fluence, their work.

Funding

This research did not receive any specific grant from funding agen- cies in the public, commercial, or not-for-profit sectors

Acknowledgements

The authors would like to thank Dr. Todd Chang, MD, MAcM and Col- leen Azen for their contributions to this study.

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