<% vol = 15 number = 2 prevlink = 83 nextlink = 93 titolo = "CLINICAL COMPARISON BETWEEN PROPHYLACTIC AND EMERGENCY TRACHEOTOMY AFTER INHALATION INJURY" volromano = "XV" data_pubblicazione = "June 2002" header titolo %>

Wei Lu, Zhao-fan Xia, Xu-lin Chen

Burn Centre, Changhai Hospital, Shanghai, People’s Republic of China


SUMMARY.Objective: To make a comparative study of prophylactic and emergency tracheotomy after inhalation injury in 93 patients treated in our burns centre in the past eight years. Method: Between January 1993 and April 2001, 93 patients with moderate or severe inhalation injury subjected to tracheotomy were enrolled in the study. On the basis of the moment of tracheotomy, the patients were divided into two groups: a prophylactic tracheotomy group (21 cases) and an emergency tracheotomy group (72 cases). Results: The moments of tracheotomy in the prophylactic tracheotomy group and the emergency tracheotomy group were respectively 4.31 ± 3.04 h and 34.47 ± 2.79 h post-burn. In the emergency tracheotomy group, the vital signs related to the operation (arterial blood oxygen partial pressure, oxygen saturation, breathing rate, and heart rate) were manifestly abnormal before the operation and markedly improved after tracheotomy. The ratio of mechanical ventilation within two days after tracheotomy was 95.23% in the emergency tracheotomy group. Conclusions: 1. Positive symptoms often occurred 30-34 h after inhalation injury in patients with moderate and even severe inhalation injury, a finding that should be carefully considered. 2. Prophylactic tracheotomy in patients with moderate or even more severe inhalation injury is of great clinical significance, while emergency tracheotomy should be avoided. 3. It is of great advantage to use a respirator in the early stages after tracheotomy.

Introduction

Inhalation injury continues to present considerable difficulties in treatment and is still a major cause of burn death. Although it has been recommended that patients with moderate or severe inhalation injury and high-risk patients with dyspnoea should undergo tracheotomy,1 burn units have varying attitudes as to the correct moment for this procedure. This technique is one of the most important steps in the treatment of inhalation injury as it can not only relieve airways obstruction due to laryngeal oedema but also facilitate phlegm suction; it is also propitious to the passage of airways secretions and exfoliated mucosae. Tracheotomy ensures clear airways when patients are being turned over and improves safety in subsequent operations that are considered to be a “life-line” for severely burned patients. However, it also presents some disadvantages. Tracheotomy causes patients considerable pain and increases the medical personnel’s workload, with added medical costs. It also increases the risk of pulmonary infection and may leave scars after extraction of the tube.

Little information is available regarding how to seize the key moment for tracheotomy in a complex clinical situation - a problem that the physicians often have to face.2-4 This paper makes a comparison between prophylactic and emergency tracheotomy after inhalation injury on the basis of 93 patients treated in our centre in the past eight years.

Materials and methods

Materials: From January 1993 to April 2001, 93 patients with moderate or severe inhalation injury who underwent tracheotomy were enrolled in the study. On the basis of the moment of tracheotomy, the patients were divided into a prophylactic tracheotomy group and an emergency tracheotomy group.

Criterion for division: Patients with manifest dyspnoea and reduced arterial blood oxygen partial pressure and oxygen saturation before tracheotomy formed the emergency tracheotomy group; patients not presenting dysfunction of ventilation and oxygen exchange formed the prophylactic tracheotomy group.

Results of division: The emergency tracheotomy group consisted of 21 patients (18 men and 3 women), 16 of whom had moderate inhalation injury and 5 severe inhalation injury.

The prophylactic tracheotomy group consisted of 72 patients (59 men and 13 women), 49 of whom had moderate inhalation injury and 23 severe inhalation injury.

Statistical analysis: All data were analysed using Student’s t test.

Results

The age of patients in the emergency tracheotomy group was similar to that in the prophylactic tracheotomy group (Table I). The total burn surface area of the patients in the prophylactic tracheotomy group was smaller than that in the emergency tracheotomy group, while the incidence of severe inhalation injury was lower and the moment of tracheotomy later in the emergency tracheotomy group.

<% createTable "Table I","Demographic and clinical features of the two groups (¯ ¯ ± s)",";;Prophylactic tracheotomy (Number = 72);mergency tracheotomy (Number = 21)@;Age (yr);33.63 ± 18.35;37.29 ± 14.15@;Burn size (TBSA%);64.05 ± 31.42;21.65 ± 19.02**@;Severe inhalation injury (%);31.09.00;23.8*@;Operation moment (PBH);4.31 ± 3.04;34.47 ± 2.79**","PBH = post-burn hour; TBSA = total body surface area; ** p < 0.01; * p < 0.05",4,300,true %>

The pre-operative conditions of patients in the emergency tracheotomy group were not good but they clearly improved 1 h post-operation, indicating the effect of emergency tracheotomy (Table II). Twenty patients (95.23%) in the emergency tracheotomy group received mechanical ventilation within two days post-operation. The pre-operative and post-operative vital signs of patients in the prophylactic tracheotomy group showed little variation.

<% createTable "Table II","Pre-operative and post-operative vital signs of patients in the emergency tracheotomy group (¯ ¯ ± s), number = 21)",";;Post-operative (l h);Pre-operative (l h)@;Arterial blood oxygen partial pressure (mm Hg); 58.74 ± 8.71**;86.29 ± 9.15@;Oxygen saturation (%);84.81 ± 8.45*;95.65 ± 4.02@;Breathing rate (resp. per min);27.00 ± 3.19*;23.00 ± 3.47@;Heart rate (beats per min);119.41 ± 18.09**;89.47 ± 11.79","p < 0.01; * p < 0.05",4,300,true %>

Discussion

The age of patients in the emergency tracheotomy group was similar to that in the prophylactic tracheotomy group (Table I). Depending on the state of the injury, the moment of tracheotomy in the prophylactic tracheotomy group was about 4 h post-burn. Burn size and the rate of severe inhalation injury were significantly higher in the prophylactic tracheotomy group than in the emergency tracheotomy group. In the emergency tracheotomy group, the moment of tracheotomy was generally about 34 h post-burn, with little variation. This was in accord with our clinical experience that the positive symptom often occurred 30-34 h after burn injury in patients with suspected of having moderate inhalation injury. The results also include five patients with severe inhalation injury in the emergency tracheotomy group. It has been reported that many patients with inhalation injury not subjected to tracheotomy had a bad prognosis. Some books and teaching material on burns state that the positive symptom appears several hours after inhalation injury, but this is mistaken. However, positive symptoms may appear late in a few patients with less severe inhalation injury, and this must be taken into account.

In patients subjected to emergency tracheotomy, the pre-operative vital signs were abnormal because of dysfunction in ventilation and oxygen exchange. Oedema in the upper respiratory tract and surrounding soft tissue caused by inhalation injury sometimes caused airways obstruction and interstitial oedema of the lung, leading to hypoxaemia. After tracheotomy, the symptoms clearly improved. Although the conditions of patients in the prophylactic tracheotomy group were worse than those in the emergency tracheotomy group, the patients’ pre-operative and post-operative vital signs showed little difference, indicating the superiority of prophylactic tracheotomy. We believe that prophylactic tracheotomy in patients with possible moderate or more severe inhalation injury is of great clinical significance and that emergency tracheotomy should be avoided. This would eliminate the difficulties caused by dysphoria and oedema of the airways surrounding the tissues of patients subjected to emergency tracheotomy.

It is very useful to use the respirator in the early stages after tracheotomy. Ninety-five per cent of our patients subjected to emergency tracheotomy received mechanical ventilation in the two days after operation, indicating that waiting is useless. The administration of mechanical ventilation immediately after tracheotomy can promptly and adequately improve oxygen supply. It can also improve airways humidification and cut down the rate of pulmonary infection, which provides a good base for future therapy.

In the light of our results, we make the following conclusions:

1. The positive symptom often occurs 30-34 h after inhalation injury in patients with moderate and even severe inhalation injury, a finding that deserves greater attention.

2. Prophylactic tracheotomy in patients with doubtful moderate or more severe inhalation injury is of great clinical significance, while emergency tracheotomy should be avoided.

3. Use of the respirator in the early stages after tracheotomy is of great value.


RESUME. But: Faire une comparaison entre la trachéotomie prophylactique et la trachéotomie d’émergence sur la base de 93 patients traités dans notre centre dans les derniers huit ans. Méthode: Entre janvier 1993 et avril 2001, 93 patients atteints de lésions d’inhalation modérées ou sévères traités avec la trachéotomie ont été inclus dans l’étude. Sur la base du moment de la trachéotomie, les patients ont été divisés dans un groupe de trachéotomie prophylactique (21 cas) et un groupe de trachéotomie d’urgence (72 cas). Résultats: Les moments de la trachéotomie dans le groupe de la trachéotomie prophylactique et le groupe de la trachéotomie d’émergence étaient respectivement 4,31 ± 3,04 h et 34,47 ± 2,79 après la brûlure. Dans le groupe de la trachéotomie d’émergence, les signes vitaux corrélés à l’opération (pression partielle de l’oxygène hématique artériel, saturation oxygénique, respiration, pulsation cardiaque) étaient notamment anormaux avant l’opération et améliorés après la trachéotomie. La proportion des patients mis en ventilation mécanique dans les deux jours après la trachéotomie était de 95,23% dans le groupe de la trachéotomie d’émergence. Conclusions: 1. Le symptôme positif se manifeste 30-34 h après la lésion d’inhalation dans les patients atteints de lésion d’inhalation modérée et même sévère, ce qui mérite majeure attention. 2. La trachéotomie prophylactique dans les patients atteints d’une possible lésion d’inhalation modérée ou plus grave est de grande importance; par contre, la trachéotomie d’émergence doit être évitée. 3. Il est très important d’utiliser le respirateur dans les premières phases après la trachéotomie.


Bibliography

  1. Shilin D., Yulian W.: Related clinical problems of inhalation injury. Zhong Hua Zheng Xing Shao Shang Wai Ke Za Zhi, 15: 405-6, 1999.
  2. Hejun W., Jie Z.: Clinical analyses of seventy-seven patients with inhalation injury. Zhong Hua Zheng Xing Shao Shang Wai Ke Za Zhi, 15: 416, 1999.
  3. Erfan X., Zongcheng Y.: Development of research on inhalation injury. Zhong Hua Zheng Xing Shao Shang Wai Ke Za Zhi, 15: 414-6, 1999.
  4. Clark W.R., jr: Smoke inhalation: Diagnosis and treatment. World J. Surg., 16: 249, 1992.
<% riquadro "This paper was received on 18 October 2001.

Address correspondence to: Dr Wei Lu, Burn Centre, Changhai Hospital, Shanghai, 200433 People’s Republic of China." %>


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