Nunn's Applied Respiratory Physiology Quotes

“Binding of oxygen to just one of the four protein chains induces a conformational change in the whole haemoglobin molecule, which increases the affinity of the other protein chains for oxygen. This ‘cooperativity’ between oxygen binding sites is fundamental to the physiological role of haemoglobin, and affects the kinetics of the reaction between haemoglobin and oxygen, which are described below.”
― Andrew B. Lumb, Nunn's Applied Respiratory Physiology

“Diaphragmatic dysfunction is a term that has been used to describe changes in the pattern of contraction of respiratory muscles in patients following major surgery. Impairment of diaphragmatic contraction is believed to result from reflex inhibition of phrenic nerve output in response to surgical trauma.”
― Andrew B. Lumb, Nunn's Applied Respiratory Physiology

“Lung volume and atelectasis. There is a continued reduction in FRC, usually reaching its lowest value 1–2 days postoperatively, before slowly returning to normal values within a week.139”
― Andrew B. Lumb, Nunn's Applied Respiratory Physiology

“Using 100% inspired oxygen before, during and at the conclusion of a general anaesthetic seems to be associated with greater severity of pulmonary atelectasis. These observations have led to the suggestion that it is time to challenge the routine use of 100% oxygen during anaesthesia.76,77”
― Andrew B. Lumb, Nunn's Applied Respiratory Physiology

“Implications of the Depression of AHVR by Anaesthetic Agents There are four important practical implications of the attenuation of AHVR by anaesthesia: 1. Patients cannot act as their own hypoxia alarm by responding with hyperventilation. 2. Patients who have already lost their sensitivity to Pco2 (e.g. some patients with chronic respiratory failure) may stop breathing after induction of anaesthesia has abolished their hypoxic drive. 3. Anaesthesia may be dangerous at very high altitude or in other situations where survival depends on hyperventilation in response to hypoxia (Chapter 17). 4. Because hypoxic drive is obtunded at subanaesthetic concentrations, this effect will persist into the early postoperative period after patients have regained consciousness and are apparently able to fend for themselves.”
― Andrew B. Lumb, Nunn's Applied Respiratory Physiology

“Shortly afterwards in 1978, Knill & Gelb13 showed that not only was the hypoxic response affected by inhalational anaesthetics but it was also, in fact, exquisitely sensitive (Figure 22.4). Hypoxic drive was markedly attenuated at 0.1 MAC, a level of anaesthesia that would not be reached for a considerable time during recovery from anaesthesia. Similar effects were found with all the currently used inhalational agents,9 and with the intravenous anaesthetic propofol.14”
― Andrew B. Lumb, Nunn's Applied Respiratory Physiology

“However, in a patient with impaired oxygenation a reduction in arterial Po2 cannot distinguish between the three very common conditions of pulmonary collapse, consolidation and oedema.”
― Andrew B. Lumb, Nunn's Applied Respiratory Physiology