Longer apnoea time with roc in the obese too

Suxamethonium increases muscle oxygen consumption as a result of skeletal muscle fasciculation. In a comparison between sux and rocuronium in rapid sequence intubation, this resulted in faster desaturation in the sux group. A further study demonstrates a similar finding in obese patients.

BACKGROUND: Rapid sequence induction may be associated with hypoxemia. The purpose of this study was to investigate the possible difference in desaturation during rapid sequence induction in overweight patients using either succinylcholine or rocuronium.

METHODS: Sixty patients with a body mass index (BMI) between 25 and 30 kg/m², American Society of Anesthesiologists class I or II, undergoing general anesthesia were randomly divided into a succinylcholine group and a rocuronium group. After a 3-min preoxygenation, patients received rapid sequence induction of general anesthesia with midazolum-fentanyl-propofol and succinylcholine (1.5 mg/kg) or rocuronium (0.9 mg/kg). Ventilation was not initiated until oxygen saturation declined to 92%. We measured the times when oxygen saturation reached 98%, 96%, 94% and 92%. Safe Apnea Time was defined as the time from administration of neuromuscular blocking drugs to oxygen saturation fell to 92%. The recovery period was defined as the time from initiation of ventilation until oxygen saturation was 97%. Arterial blood gases were taken at baseline, after preoxygenation and at 92% oxygen saturation.

RESULTS: The mean Safe Apnea Time (95% CI) was 283 (257-309) s in succinylcholine vs. 329 (303-356) s in rocuronium (P=0.01). The mean recovery period (95% CI) was 43 (39-48) s in succinylcholine vs. 36 (33-38) s in rocuronium (P=0.002). Blood gas analysis showed no difference between the two groups.

CONCLUSIONS: Succinylcholine was associated with a significantly more rapid desaturation and longer recovery of oxygen saturation than rocuronium during rapid sequence induction in overweight patients.

Desaturation following rapid sequence induction using succinylcholine vs. rocuronium in overweight patients
Acta Anaesthesiol Scand. 2011 Feb;55(2):203-8

Pre-hospital transcranial Doppler

The SAMU (Service d’aide médicale urgente) guys have had a run of interesting pre-hospital publications lately. In this study, one of their ultrasound-wielding physicians travelled in a car to meet comatose head injured patients in a large semi-rural territory area with up to a 120–160-min transport time to a hospital with emergency neurosurgical capability. Pre-hospital transcranial Doppler was done, the results of which appear to have influenced treatment decisions, including the pre-hospital administration of noradrenaline (norepinephrine). I think this study has answered the ‘can it be done?’ question, but further work is needed to determine whether it really makes a difference to outcome.

Background: Investigation of the feasibility and usefulness of pre-hospital transcranial Doppler (TCD) to guide early goal-directed therapy following severe traumatic brain injury (TBI).
Methods: Prospective, observational study of 18 severe TBI patients during pre-hospital medical care. TCD was performed to estimate cerebral perfusion in the field and upon arrival at the Level 1 trauma centre. Specific therapy (mannitol, noradrenaline) aimed at improving cerebral perfusion was initiated if the initial TCD was abnormal (defined by a pulsatility index >1.4 and low diastolic velocity).
Results: Nine patients had a normal initial TCD and nine an abnormal one, without a significant difference between groups in terms of the Glasgow Coma Scale or the mean arterial pressure. Among patients with an abnormal TCD, four presented with an initial areactive bilateral mydriasis. Therapy normalized TCD in five patients, with reversal of the initial mydriasis in two cases. Among these five patients for whom TCD was corrected, only two died within the first 48 h. All four patients for whom the TCD could not be corrected during transport died within 48 h. Only patients with an initial abnormal TCD required emergent neurosurgery (3/9). Mortality at 48 h was significantly higher for patients with an initial abnormal TCD.
Conclusions: Our preliminary study suggests that TCD could be used in pre-hospital care to detect patients whose cerebral perfusion may be impaired.

Pre-hospital transcranial Doppler in severe traumatic brain injury: a pilot study
Acta Anaesthesiol Scand. 2011 Apr;55(4):422-8

Tube tip top tip

I’m not sure what this offers over purpose-built supraglottic airways, but effective ventilation may be achieved after failure of mask ventilation by siting a tracheal tube with its tip in the pharynx and the cuff inflated with 20 mls. The tube ‘is gently inserted 10—14cm, dependent on patient size, or until any resistance is felt, in caudal direction by letting the tip of the tube follow the palate and the posterior pharyngeal wall (in order to place the tip of the tube posterior to the epiglottis)’. As long as the tube tip or Murphy eye is not in the oesophagus, ventilation should be possible. The hand position maintains a jaw thrust while closing the mouth and occluding the nostrils.

BACKGROUND: Mask ventilation occasionally fails. Alternative readily available and simple methods to establish ventilation in these cases are needed.

METHODS: Retrospective description of cases in which a new technique, tube tip in pharynx (TTIP) ventilation, was employed for restoring ventilation in case of failed facemask ventilation during induction of anaesthesia. The technique involves a standard endotracheal tube and can be performed single-handed: A standard endotracheal tube was placed via the mouth with the tip in the pharynx and the cuff was inflated. By placing the fourth and fifth fingers below the ramus of the mandible, the third finger below the lower lip, the second finger above the upper lip and on one side of the nose and the first finger on the other side of the nose, an open airway is restored. Chin lift is inherent in the grip, thus contributing to opening of the airway.

RESULTS: In all four cases of failed mask ventilation the anaesthetist could establish an open airway and subsequent ventilation without the need for an assistant. There were no indications of gastric insufflation.

CONCLUSION: The TTIP technique established ventilation in all four patients after abandoned facemask ventilation. The technique only involves one person and an endotracheal tube and warrants to be included in the armamentarium of anaesthetists. Further prospective studies are needed to refine the technique and delimit its indications.

Tube tip in pharynx (TTIP) ventilation: simple establishment of ventilation in case of failed mask ventilation
Acta Anaesthesiol Scand. 2005 Feb;49(2):252-6