Summary Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flowcharts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS. Disclaimer: It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.

/pdf/difficult-airway-society-guidelines-for-management-of-the-33migw5s09.pdf

Difficult Airway Society guidelines for management of the unanticipated difficult intubation

Part 8 : Advanced life support : 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

https://www.ahajournals.org/doi/pdf/10.1161/CIRCULATIONAHA.110.971051

Part 8: Advanced Life Support: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension (PH) characterised by preferential remodelling of the pulmonary venules. In the current PH classification, PVOD and pulmonary capillary haemangiomatosis (PCH) are considered to be a common entity and represent varied expressions of the same disease. The recent discovery of biallelic mutations in the EIF2AK4 gene as the cause of heritable PVOD/PCH represents a major milestone in our understanding of the molecular pathogenesis of PVOD. Although PVOD and pulmonary arterial hypertension (PAH) share a similar clinical presentation, with features of severe precapillary PH, it is important to differentiate these two conditions as PVOD carries a worse prognosis and life-threatening pulmonary oedema may occur following the initiation of PAH therapy. An accurate diagnosis of PVOD based on noninvasive investigations is possible utilising oxygen parameters, low diffusing capacity for carbon monoxide and characteristic signs on high-resolution computed tomography of the chest. No evidence-based medical therapy exists for PVOD at present and lung transplantation remains the preferred definitive therapy for eligible patients.

https://erj.ersjournals.com/content/erj/47/5/1518.full.pdf

Pulmonary veno-occlusive disease

Pulmonary hypertension is characterised by the chronic elevation of pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) leading to right ventricular enlargement and hypertrophy. Pulmonary hypertension may result from respiratory and cardiac diseases, the most severe forms occurring in thromboembolic and primary pulmonary hypertension. Pulmonary hypertension is most often defined as a mean PAP >25 mmHg at rest or >30 mmHg during exercise, the pressure being measured invasively with a pulmonary artery catheter. Doppler echocardiography allows serial, noninvasive follow-up of PAPs and right heart function. When the adaptive mechanisms of right ventricular dilatation and hypertrophy cannot compensate for the haemodynamic burden, right heart failure occurs and is associated with poor prognosis. The haemodynamic profile is the major determinant of prognosis. In both primary and secondary pulmonary hypertension, special attention must be paid to the assessment of pulmonary vascular resistance index (PVRI), right heart function and pulmonary vasodilatory reserve. Recent studies have stressed the prognostic values of exercise capacity (6-min walk test), right atrial pressure, stroke index and vasodilator challenge responses, as well as an interest in new imaging techniques and natriuretic peptide determinations. Overall, careful haemodynamic evaluation may optimise new diagnostic and therapeutic strategies in pulmonary hypertension.

https://erj.ersjournals.com/content/erj/20/5/1314.full.pdf

Haemodynamic evaluation of pulmonary hypertension

Cricoid pressure is used to protect the lungs from contamination with gastric contents during tracheal intubation. We studied the effect of cricoid pressure applied with a yoke on 30 anaesthetised patients examined fibreoptically through a laryngeal mask airway. We assessed the effect of 20, 30 and 44 N on the internal appearance of the cricoid and vocal cords. Difficulty in ventilation was also recorded. At 44 N, cricoid deformation occurred in 27/30 patients (90%) and 15/30 (50%) had cricoid occlusion [13/30 (43%) had cricoid occlusion at 30 N and 7/30 (23%) at 20 N]. Associated difficulty in ventilation was present in 15 patients (50%) and 18/30 (60%) had vocal cord closure with associated difficult ventilation, at forces up to 44 N. Cricoid occlusion was unrelated to age and body mass index but females were at greater risk. Orthodox values of cricoid pressure, applied with a yoke, may produce obstruction at the level of the cricoid cartilage or vocal cords, with implications for tracheal intubation and ventilation by mask.

https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-2044.2000.01207.x

The effect of cricoid pressure on the cricoid cartilage and vocal cords: an endoscopic study in anaesthetised patients.

he Sellick maneuver is designed to protect the airway against aspiration of gastric contents T before tracheal intubation and in an emergency to permit safe ventilation via a mask (1). For this maneuver itself to prevent ventilation is highly unusual. We report an adult patient in whom tracheal intubation was defeated by an undiagnosed supraglottic mass, and whose airway was completely obstructed by the application of the Sellick maneuver.

The Sellick maneuver causing complete airway obstruction.

Pulmonary artery catheters are frequently used to measure pulmonary vascular pressures, particularly the pulmonary wedge pressure (Pw), which reflects pulmonary venous and ideally left atrial pressures. However, the pulmonary capillary pressure (Pc) is the major force in the formation of pulmonary edema. Unfortunately, Pw has been interpreted as being identical to Pc. In this study we used 7-Fr pulmonary artery catheters to measure effective Pc in closed-chest animals and patients. The decreasing pressure profile after pulmonary artery occlusion was separated into fast and slow components, with the inflection point between them representing Pc. Pc was also estimated by mathematically analyzing the curves in terms of a precapillary resistance, a large pulmonary capillary capacitor, and a postcapillary resistance. In dogs, Pc was determined after pulmonary vascular resistance had been increased by infusing serotonin and histamine. While Pw remained unchanged, serotonin increased pulmonary artery pressure (Ppa) 52% and Pc 16%, whereas histamine increased Ppa only 25%, but increased Pc by 35%. This is consistent with studies showing that serotonin primarily elevates precapillary resistance, and histamine increases postcapillary resistance. In thoracic surgery patients, Pc was not consistently related to Pw. This measurement was simple, reproducible, and provided a more precise capillary filtration pressure than Pw. It should be clinically useful in monitoring patients with pulmonary hypertension and adult respiratory distress syndrome, especially those with pulmonary artery catheters.

Measurement of effective pulmonary capillary pressure using the pressure profile after pulmonary artery occlusion.

L'anesthesie locale du muscle uterin associee a une rachi-anesthesie permet d'eviter les problemes majeurs dans les cas de dystrophie myotonique

John N. Miller

Papers

The Sellick maneuver causing complete airway obstruction.

Measurement of effective pulmonary capillary pressure using the pressure profile after pulmonary artery occlusion.

Local and spinal anesthesia for cesarean section in a patient with myotonic dystrophy.

Local and Spinal Anesthesia for Cesarean Section in a Patient with Myotonic Dystrophy