Perioperative treatment algorithm for bleeding burn patients reduces allogeneic blood product requirements.

BACKGROUND: Surgical excision of burn wounds is often associated with severe bleeding. Timely and targeted correction of coagulopathy reduces transfusion requirements and improves survival in trauma victims. We hypothesized that rapid correction of coagulopathy after a treatment algorithm based on point-of-care viscoelastic coagulation testing would decrease allogeneic blood product transfusions during surgical excision of burn wounds. METHODS: Thirty consecutive patients undergoing surgical excision of burn wounds were enrolled into this prospective, randomized, controlled, single-centre study. In the control group, coagulation management was performed according to the clinicians' discretion. For the algorithm group, we standardized treatment based on the Austrian recommendation for the management of trauma-induced coagulopathy using point-of-care rotational thromboelastometry (ROTEM(®)). The main outcome parameter was the cumulative number of allogeneic blood units transfused on the day of surgery. RESULTS: The difference between the groups regarding the cumulative use of allogeneic blood products was highly significant with 3.0 (1.3-5.5) blood products in the algorithm group compared with 9.0 (6.0-12.3) in the control group [median (inter-quartile range); P=0.002]. No plasma was administered in the algorithm group compared with 5.0 (1.5-7.5) units overall in the control group (P<0.001). Fibrinogen concentrate administration was not significantly different between the groups (P=0.89). Tranexamic acid was not administered. CONCLUSIONS: The significant reduction in allogeneic blood product requirements during surgical burn wound excision is a prospective proof of concept that a bleeding management algorithm based on thromboelastometry is efficacious. Hypofibrinogenaemia and hyperfibrinolysis are not significant pathomechanisms of bleeding in this setting and ROTEM(®) helps to avoid unnecessary interventions.

Force distribution across the heel of the hand during simulated manual chest compression.

According to most published guidelines of cardiopulmonary resuscitation chest compression is performed on the lower half of the sternum by compressing the sternum with the heel of one hand and the other hand on top of the first. In all guidelines and during CPR training great importance is attributed to exact localisation of the so-called compression point. In a laboratory investigation we assessed the force distribution across the heel of the hand and defined the total breadth in contact with the sternum. In order to find out whether there is any difference in the force pattern with the right or the left hand in direct contact with the sternum we determined the resultant maximal force of that part of the heel of the hand exerting the maximal force. A total of 12 anaesthetists performed simulated chest compressions onto a flat surface covered with an integrated force sensor mat. The distance between the most ulnar part and the most radial part of the hand was determined to be 9.2 cm. Similar mean total forces were measured (right hand in contact: 644 N; left hand in contact: 621 N). In all except one anaesthetist the hypothenar part of the heel exerted a significantly higher force compared to the thenar part, independent of whether the right hand or the left hand was in contact. The distance between points of maximal force when the right hand or when the left hand in contact was 2.2 cm corresponding to the breadth of one and a half fingers. To reduce the potential risk of sternal fractures by chest compressions applied too far in a cephalad direction, we recommend use of the right hand in contact if the rescuer kneels at the right side of the patient and vice versa.

A new prototype of an electronic jet-ventilator and its humidification system.

BACKGROUND: Adequate humidification in long-term jet ventilation is a critical aspect in terms of clinical safety. AIM: To assess a prototype of an electronic jet-ventilator and its humidification system. METHODS: Forty patients with respiratory insufficiency were randomly allocated to one of four groups. The criterion for inclusion in this study was respiratory insufficiency exhibiting a Murray score above 2. The four groups of patients were ventilated with three different respirators and four different humidification systems. Patients in groups A and B received superimposed high-frequency jet ventilation (SHFJV) by an electronic jet-ventilator either with (group A) or without (group B) an additional humidification system. Patients in group C received high-frequency percussive ventilation (HFPV) by a pneumatic high-frequency respirator, using a hot water humidifier for warming and moistening the inspiration gas. Patients in group D received conventional mechanical ventilation using a standard intensive care unit respirator with a standard humidification system. SHFJV and HFPV were used for a period of 100 h (4days). RESULTS: A significantly low inspiration gas temperature was noted in patients in group B, initially (27.2 +/- 2.5 degrees C) and after 2 days (28.0 +/- 1.6 degrees C) (P < 0.05). The percentage of relative humidity of the inspiration gas in patients in group B was also initially significantly low (69.8 +/- 4.1%; P < 0.05) but rose to an average of 98 +/- 2.8% after 2 h. The average percentage across all four groups amounted to 98 +/- 0.4% after 2 h. Inflammation of the tracheal mucosa was found in patients in group B and the mucosal injury score (MIS) was significantly higher than in all the other groups. Patients in groups A, C and D showed no severe evidence of airway damage, exhibiting adequate values of relative humidity and temperature of the inspired gas. CONCLUSION: The problems of humidification associated with jet ventilation can be fully prevented by using this new jet-ventilator. These data were sustained by nondeteriorating MIS values at the end of the 4-day study period in groups A, C and D.

Supralaryngeal tubeless combined high-frequency jet ventilation for laser surgery of the larynx and trachea.

We have developed a new technique of combined high-frequency jet ventilation (HFJV), characterized by simultaneous application of a low-frequency (LF) and a high-frequency (HF) jet stream. Tubeless supralaryngeal jet ventilation was delivered via a modified Kleinsasser laryngoscope. We studied 44 adults undergoing 45 elective surgical procedures of the larynx and trachea using a carbon dioxide laser during HFJV. Applied inspiratory oxygen ratios ranged from 0.4 to 1.0. Mean driving pressures of the HF and LF jet streams were 1.5 bar and 1.8 bar in adults, respectively. Mean duration of HFJV was 41 (range 10-180) min. HFJV resulted in mean PaO2 and PaCO2 values of 16.6 (range 9.8-26.9) kPa and 5.7 (3.0-7.6) kPa, respectively. Tubeless supralaryngeal HFJV was safe and effective in maintaining gas exchange in the presence of laryngeal or tracheal stenoses, providing optimal visibility of anatomical structures, offering maximum space for surgical manipulation, and avoiding the use of combustible material inside the larynx or trachea.

[Clinical experiences with the double jet technique superimposed HFJV (high frequency jet ventilation) during larygotracheal surgery]. / Klinische Erfahrungen mit der Doppel-Jet-Technik: Die Superponierte Hochfrequenz-Jet-Ventilation in der Larynxchirurgie.

OBJECTIVE: Single-frequency high-frequency jet ventilation (HFJV) is an established ventilatory technique during laryngotracheal surgery. This study describes the clinical use of combined HFJV, characterised by the simultaneous application of a low-frequent (LF) and a high-frequent (HF) jet stream. METHODS: Two jet streams with different pulsatile frequency (HF approx. 10 Hz, LF 10-30 bpm) and adjustable driving pressures were applied supraglottically by means of a special jet laryngoscope in patients undergoing elective laryngotracheal surgery during total intravenous anaesthesia. HFJV was performed using a pneumatic or electronic jet respirator connected to the central gas supply. RESULTS: 134 patients were submitted to tubeless HFJV applying the double-jet technique using the jet-laryngoscope. Duration of HFJV was < or = 30 min in 60 patients (45%), between 30 and 60 min in 49 patients (36%), and > or = 60 min in 25 patients (19%). Classification into 3 groups according to weight ((I < 65 kg, II = 65-84 kg, III > or = 85 kg) using driving pressures of 1.52 +/- 0.47 bar, 1.64 +/- 0.78 bar, and 1.69 +/- 0.67 bar for the HF jet and 1.78 +/- 0.54 bar, 1.90 +/- 0.48 bar, and 2.00 +/- 0.49 bar for the NF jet demonstrated differences in paO2 (156 +/- 45 [I] vs 126 +/- 34 [II] vs 96 +/- 18 [III] mm Hg) and paCO2 (42 +/- 9 und 44 +/- 8 vs 48 +/- 8 mm Hg) using comparable FjetO2 (0.6 +/- 0.2). Supraglottic pressures were 11.6 +/- 6.8, 11.5 +/- 7.0, und 12.6 +/- 7.1 cm H2O (I-III). No ventilator-related adverse events were observed. CONCLUSION: Tubeless supraglottic HFJV utilizing two jet streams with low and high frequency was effective in patients during laryngotracheal surgery. The application of two jet streams results in phasic changes of airway pressures between an inspiratory and expiratory pressure level, and facilitates application of enlarged tidal volumes. As demonstrated, oxigenation and ventilation is compromised by increased body weight. Superimposed HFJV (double-jet technique) enables the supraglottic ventilation of heavy patients and/or in the presence of airway stenoses during laryngotracheal surgery without need to use maximum driving pressures.