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January - March 2004: 
Volume 17, Issue 1

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Νear drowning: Clinical presentation in adults
Abstract
To study retrospectively the clinical manifestations and course of near-drowning in sea water. Adult patients who presented to a district hospital with near-drowning, from 11/6/1994 to 1/9/2001. In all 35 patients (24 female, 11 male), aged 18-88 were studied. Of the patients, 28 were elderly (³65 years). Immediately after rescuing at the seaside, 10 of the patients had a GCS <9 and 6 had a GCS of 9-14. At presentation, 7 patients had a GCS <15 and two of them were still comatose and had to be intubated for airway protection. Α third patient had to be intubated within the first 24 hours, because of ARDS. In all, 4 patients had to be transferred to an ICU - 2 of them because of coma and 2 because of acute respiratory failure. Of the comatose patients, one died because of ventilator-associated pneumonia. No other fatalities were observed. All patients, with two exceptions, had a PaO2/FiO2 <300 at presentation. Criteria of ARDS were fulfilled in 14 and criteria of ALI (acute lung injury) in 12 cases. Superimposed pneumonia was observed in 4 patients (one intubated). Improvement of arterial blood gases was rapid in most cases and 24 hours after presentation, only 6 patients still had ARDS. A worsening of gas exchange after the first day was observed in 2 cases. Duration of hospitalization varied from 2 tο 11 days (5,23±0,47 days, mean±SEM). Duration of hospital stay was significantly longer in patients who presented with GCS <15 (7,57±0,78 vs 4±0,79 days, p=0,023). In the absence of serious neurologic impairement, near drowning victims, even when they are elderly, can be expected to have a good outcome, despite the frequent presence of severe acute respiratory failure. Pneumon 2004, 17(1):72-79.
Full text

Introduction

Near-drowning is the third leading cause of accidental death; among those who are under 44 years old it is the second leading cause of accidental death. The majority (approximately 60%) of near-drowning victims are younger than 20 years old. Although the outcome of near-drowning is primarily associated with the development of anoxic encephalopathy, these patients mostly present with acute respiratory failure, often accompanied by severe disturbances in arterial blood gases.1 We present our experience on near-drowning in sea water, with special emphasis on its effects on the respiratory system of the victim. Our series includes only adults, the majority of whom are over 60 years of age. It should be noted that, although age does not appear to be related to the final outcome of near-drowning,2 the elderly have not been adequately represented in relevant studies,2-4 so that data on this patient group remain scant.

Material-Methods

We present a retrospective study of patients admitted with the diagnosis of near-drowning in our department in the period from 11/6/1994 till 1/9/2001. Medical records were reviewed and data on consciousness level after rescue and at hospital admission, symptoms, blood gas analyses and serum electrolyte levels were obtained. Patients were grouped according to the Conn-Barker scale for near-drowning.5 Chest radiographs were evaluated by two pulmonary medicine specialists as regards the kind and the extent of parenchymal damage. The pulmonary disorder was identified as either acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) according to the relevant consensus criteria established in 1994.6 In addition, data on the duration of hospitalization, the presence or absence of late complications and the course of normalization of blood gas levels and radiographic changes were also evaluated. Values are reported as mean±SEM. Statistical analysis was performed using the Kolmogorov-Smyrnov test (for the assessment of normal distribution of the values of the study variables), chi-square test and Pearson correlation coefficient.

 

Results

We studied thirty-five patients (24 female, 11 male), aged 18-88 years (mean age±SEM 69.2±2.68 years). The majority of the patients (80%) were elderly (>65 years of age). Two patients had a cardiac arrest, but resuscitation attempts were unsuccessful and death was confirmed a few hours later in the emergency department; these patients were not included in the study. In all cases, near-drowning occurred as an accident during swimming in sea water in the summer. Seventeen patients had a history of chronic disease (heart disease in 10 cases).

Near-drowning was the primary event in 23 patients (65.7%); in the rest of the patients near-drowning was secondary to the following events: Alcohol intoxication (1 case), drug abuse (1 case), ischemic pain (1 case), seizures (1 case), trauma (1 case), hypoglycemia (1 case), transient ischemic attack (1 case), dizziness with or without palpitations (5 cases). The duration of submersion time is unknown for the majority of the patients. Serious injuries (in the head, spine etc) attributable to drowning were not recorded. Immediately after rescue, 10 patients were comatose (GCS £8) and 6 patients had a GCS of 9-14. Most patients soon regained consciousness. When they arrived at the hospital, 22 patients had an A score according to the Conn-Barker scale, 5 patients had a B score, one patient had a C1 score and one had a C3 score. The two comatose patients were immediately intubated to ensure airway patency. An additional patient was intubated a few hours later due to ARDS.

In the emergency department, none of the patients were pulseless, apneoic, or hypotensive, whereas two patients had mild hypothermia. In addition, during the first day of hospitalization, seven patients had axillary temperature above 37.3 oC (but not higher than 38.3 oC), without evidence of infection.

 

Table 1. Symptoms and signs from the respiratory system at admission. Total number of patients=34.

Dyspnea                           79.4%        

Cough                               58.8%        

Tachypnea (>30/min)        50.0%        

Wheezing                          35.3%        

Crackles                            79.4%        

Prolonged expiration          20.6%

 

 

All patients presented signs and symptoms of respiratory distress (Table 1). Arterial blood gas analyses and laboratory findings at hospital admission are listed in Table 2. In the emergency department, the PaO2/FiO2 ratio ranged from 99-361 mmHg (215.9±10.6 mmHg) and was significantly associated with the following: (a) consciousness level in the emergency department (r=0.482, P=0.003), (b) serum sodium levels (r=-0.42, P=0.014), (c) leucocytosis (r=-0.428, P=0.002). A significant association between the PaO2/FiO2 ratio and age or consciousness level at the scene of the accident was not found.

 

Table 2. Laboratory findings in patients with near-drowning at hospital admission.

                                                             Standard

                             Mean value ± SEM   deviation        

PaO2/FiO2 (mmHg)   215.86 ± 10.64           63

pH                                7.38±0.01              0.1

Base Excess (mEq/lit)    -1.5±0.4               2.6

Serum sodium (mEq/lit) 147.6±0.9             5.25

Serum potassium (mEq/lit) 3.8±0.1             0.6

White blood cells/μl     12888±695            4054

Neutrophils/μl           10642±696          4058

 

As regards chest radiographs, 28 patients showed bilateral infiltrates (radiomorphology of pulmonary edema). Additional data on these patients are presented in Table 3. Patients with perihilar opacity had the milder disturbances in gas exchange.

Table 3. Number of patients with near-drowning and bilateral infiltrates on chest radiograph at hospital admission.

                                          Perihilar alveolar opacity       Diffuse alveolar opacity        Interstitial pattern

Bilateral symmetric findings                  5                                          12                                     3

Asymmetric findings                             1                                           5

                                             (right predominance)         (right predominance in 4)

Total                                                    6                                       17                                    3

 

 

At admission, 12 patients met the ARDS criteria and 14 met the ALI criteria. Furthermore, 2 patients showed radiographic findings compatible with pulmonary edema and had a PaO2/FiO2 ratio >300 mmHg. Four patients had localized alveolar infiltrates (lobar or segmental) accompanied by hypoxemia; three of these patients had a PaO2/FiO2 ratio <300 mmHg and normal findings on chest radiograph. There were no additional abnormal radiographic findings (sand bronchogram, Kerley lines, pleural effusion).

Four patients were transferred to the ICU due to either neurological damage (2 cases) or acute respiratory failure (2 cases). Of the respiratory failure cases, one was intubated and required mechanical ventilation, whereas the other one was effectively managed with non-invasive ventilation. In two of the intubated patients, the tracheal tube was removed successfully at 48 and 96 hours, respectively. The patient who had a C3 score according to the Conn-Barker scale remained in vegetative condition and died three weeks later due to pneumonia and sepsis. No other fatalities were observed. All patients were treated with furosemide and supplemental oxygen therapy. No steroids were administered. All patients received prophylactic antibiotic therapy. Four patients developed pneumonia (fever >38.3 oC, with new and persistent localized infiltrates, purulent secretions and an elevation in white blood cells); one of these patients was intubated, as already mentioned. In all cases, pneumonia was a late complication (occurred after day 4). Klebsiella pneumoniae was isolated in the mechanically ventilated patient; bacteriological confirmation was not possible in the rest of pneumonia cases. All intubated patients with clinical suspicion for pneumonia responded to empirical antibiotic treatment. Findings of sepsis or secondary organ failure were absent in patients who were not intubated.

In most cases of near-drowning, hypoxemia improved rapidly within the first 24 hours after hospital admission, with only 6 patients still meeting ARDS criteria after day 1 (Figure 1). Deterioration of gas exchange a few hours after admission was observed in two patients; nevertheless, none of these patients required tracheal intubation. Hypoxemia had returned to normal (PaO2/FiO2 ratio >300 mmHg) by day 4 in 76.5% of the cases (Figure 2). Also, radiographic findings had disappeared by day 4 in the same percentage of patients (Figure 3). Radiographic aggravation after day 1 occurred only in patients whose course was complicated by pneumonia. Delayed normalization of oxygen levels (after the first week) was reported in 3 cases and delayed improvement of radiographic findings in 4. In three cases, delayed radiographic improvement was attributed to the subsequent development of pneumonia.

 

Image 1

Pulmonary disorder

Figure 1. Type of pulmonary disorder at admission (light-colored columns) and on day 2 (dark colored columns). 1=PaO2/FiO2<300 with normal chest radiograph, 2=ALI, 3=ARDS, 4=other, 5=PaO2/FiO2>300 with normal chest radiograph.

Image 2

Day of hospitalization

Figure 2. Normalization of hypoxemia (PaO2>60 mmHg) without supplemental oxygen therapy.

Image 3

Day of hospitalization

Figure 3. Normalization of findings on chest radiograph.

 

Patients were discharged after a 2-11 day hospitalization (mean value±SEM 5.23±0.47 days). There was no significant difference in the duration of hospitalization between patients with ALI and patients with ARDS. The PaO2/FiO2 ratio was not significantly associated with the duration of the hospital stay. Only the presence of a GCS<15 at presentation influenced the duration of the hospital stay (7.57±0.78 vs. 4±0.79 days, P=0.023).

Discussion

We retrospectively studied 35 cases of near-drowning in sea water; study subjects were mainly elderly. Despite advanced age, the presence of severe lung injury and coexisting chronic diseases, the final outcome was generally good, with a fatality rate of 2.86% and without late neurologic complications. In large series,5,6 fatality rates in near-drowning victims range from 9-12%, without significant differences between drowning in sea or fresh water. The primary determinant of the final outcome is neurologic status. Patients presenting with confusion in the emergency department have a poorer outcome compared to those who were conscious. The worse outcome was observed among patients presenting with coma2,3,8-10.

All study subjects had lung involvement -in some cases, severe- but they were hemodynamically stable. None of the victims (with only one exception) showed signs of severe neurologic damage at hospital admission. Although the available data about their clinical condition after rescue are few, the majority of the victims must have had a grade of 2-3 in the Spilzman grading scale.3 Predicted mortality in these patients is 0.6-5.2%3. However, near-drowning victims in this large series were predominately young people (mean age±SEM 22.7±11.5 vs 69.2±2.68 in our series). Despite advanced age, the final outcome of our patients was not significantly different from that reported in the study conducted by Spilzman provided that the clinical condition of the patients in the two studies was similar.

The proportion of patients who suffered near-drowning as a secondary event was unusually high in our study. Although secondary near-drowning is commonly reported to be caused by excessive alcohol consumption or drug use, myocardial infarction or trauma, these cases were rare in our study.1 Taking into account the advanced age of our subjects, it is not surprising that the most common cause of secondary near-drowning was a vague feeling of dizziness, which could be suggestive of transient cardiac rhythm disturbances, at least in some cases. There was no significant difference in gas exchange disturbances and hospital stay between primary and secondary near-drowning victims. Since all but one patient had a good final outcome, the possible relationship between secondary near-drowning and survival cannot be evaluated; nevertheless, Spilzman did not observe a worse outcome among victims of secondary near-drowning3.

Despite the clear predominance of men in all studies of submersion in water,1 the majority of victims in our series were female. A possible reason for this discrepancy might be that the tendency of males to practice risky behaviors decreases with age. It might also indicate that old women are less familiarized with water and aware of the risks associated with swimming.

Despite the low incidence of neurologic deficits in our study, all patients had suffered lung injury, in several cases severe. Since there is an established association between neurologic damage and the amount of aspirated fluid, an increased susceptibility of the lungs of the elderly to the effects of submersion in water might be suggested, with caution though.  However a significant association between the PaO2/FiO2 ratio and age was not found.

Our radiographic findings are similar to those reported in the literature.10-15 Nevertheless, we found a high incidence of pulmonary edema (80%). In consistence with the findings of Hunter TB et al,11 we observed that cases with predominantly perihilar opacity have milder hypoxemia. Asymmetric radiographic infiltrates are reported in other series as well and are explained by the position of the body.11

The right predominance of the radiographic findings in cases of asymmetry is most probably attributable to the aspiration of a greater amount of fluid in the right lung. In addition, we saw some cases of focal consolidation, probably due to local aspiration of fluid. An unusual finding in cases of near-drowning is the presence of sand bronchogram.15 In our study there was no such finding.

Development of ARDS in initially asymptomatic patients with normal chest radiographs is reported in the literature, although rarely;11,13,14 we had no such case in our series, however. In consistence with previous studies,8,14 several patients with normal chest radiographs had hypoxemia; nevertheless, patients with ALI or ARDS already showed findings compatible with pulmonary edema on chest radiographs obtained when they presented in the emergency department. All patients without se­condary lung damage (infection) demonstrated a constant improvement in radiographic findings after the first 24 hours -even those two patients who had a temporary deterioration of gas exchange on day 2.

Nearly one third of the patients met ARDS criteria. Nevertheless, only one patient was intubated due to respiratory failure. Previous studies report a much higher percentage of tracheal intubation in victims of near-drowning, and prominent findings on chest radiographs.2,4 Due to the inadequate number of available ICU beds, all but one non-intubated patients, were successfully managed in the medical department. The single non-intubated patients who was transferred to the ICU was effectively managed with non-invasive mechanical ventilation. Near-drowning victims who are conscious and have spontaneous respiration are reported to improve with the use of continuous positive airway pressure (CPAP), probably as a result of recruitment of areas with atelectasis and, thus, shunt reduction. To our knowledge, there are no reports on the use of non-invasive mechani­cal ventilation in near-drowning victims; however, in view of the relatively rapid improvement of pulmonary dama­ge it appears to be an interesting approach that would reduce the need for tracheal intubation in these patients.

Pneumonia is a serious and, sometimes, fatal complication of near-drowning.18 It has a widely varying repor­ted incidence. In a study of 91 near-drowning victims by Model et al there was only one case of pneumonia,2 whereas another study reports 16 cases of pulmonary infection in 40 near-drowning victims.15 Van Berkel et al studied 102 patients with near-drowning and reported that the incidence of pneumonia in these patients was 14.7%. The occurrence of pneumonia appears to be related to mechanical ventilation, since it is rarely seen in non-intubated patients (incidence of pneumonia in intubated patients 52% vs 3% in non-intubated patients).4 Apparently, aspiration of good quality pure water is associated with a low incidence of pneumonia in non-intubated patients.9 Sometimes, unusual pathogens (Aeromonas, fungi) are detected in patients who aspirated fluid that contained the respective pathogens. Such infections commonly occur within the first days after submersion. They may have a fulminant course and be accompanied by bacteremia and sepsis; moreover, such infections are associated with high mortality rates.18 In our study, a pulmonary infection was suspected on clinical grounds in 3 non-intubated patients. Consequently, the incidence of pneumonia in non-intubated patients does not exceed 11.8%. All near-drowning victims in our series developed pneumonia as a late complication, which suggests a nosocomial origin of the infection rather than a result of aspiration of microorganisms during submersion in sea water.

Prophylactic antibiotic therapy in near-drowning has not been shown to be beneficial in three relevant retrospective studies.2,4,15 Chemoprophylaxis is not recommended as a routine, although cases of massive aspiration of fluid or near-drowning in contaminated water may be an exception.18 However, prophylactic antibiotic therapy seems to be routinely given in practice.16 All our patients received antibiotics prophylactically.

Our study shows that patients with near-drowning not requiring tracheal intubation within the first 24 hours have a good final outcome after a relatively short hospital stay, irrespective of their age. Commonly, patients who are not comatose at presentation, recover rapidly and without serious complications, despite the severe acute respiratory failure that may initially be present. Such patients may be effectively treated in a medical department and not necessarily in an ICU. Patients presenting with confusion or drowsiness are expected to require a longer stay in hospital.

 

 

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References