The effect of pregnancy on pulmonary nitrogen washout

Abstract

SummaryPre-oxygenation times were studied in 30fit pregnant women during the course of their pregnancy. The mothers were studied in the supine position with a left lateral tilt and breathing through a standard Magill system with an oxygenflopi. rate o f 8 litreslminute. Between 13-26 weeks gestation and 26-42 M>eek.r t h~ times needed to achieve un end-tidal nitrogen Of2Y0 1 4 w e I04 .second,s ( S D 30) and 80 seconds ( S D 20), respectiveL-y. A control group of young women of similar age and weight needed 130 seconds (SD 30) to achieve the same end-tidal nitrogen concentration. A gas-tight mask was found to he essential to achieve efective denitrogenation (end-tidal nitrogen concentration of 2%).

Pre‐oxygenation in pregnancy: an investigation using physiological modelling

“…This difference is predicted by increased ventilation of a relatively small functional residual capacity in pregnancy. This finding is in keeping with those of previous researchers [10–12]. We found that 2 min tidal breathing of 100% oxygen ensured > 95% complete pre‐oxygenation in full‐term pregnancy.…”

“…Reduced functional residual capacity, coupled with increased minute ventilation, predicts more rapid pre‐oxygenation. There is a modest body of research in small numbers of subjects to support this [10–12]. However, research in pregnant patients suffers from ethical and practical constraints that have limited the work in this field.…”

Преоксигенация: Терминология, Физиологические Основы, Техники Проведения, Методики Повышения Эффективности, Особенности У Критических Пациентов, Возможные Риски

“…Максимальная преоксигенация у этих пациенток может быть достигнута быстрее за счет высокой альвеолярной вентиляции и сниженной ФОЕ. Однако во время апноэ беременные женщины склонны к более быстрому развитию десатурации оксигемоглобина из-за ограниченного объема кислорода в их сниженной ФОЕ в сочетании с повышенным потреблением кислорода (VО 2 ) [24].…”

Validation of two preoxygenation techniques, 3 min tidal volume breath and eight vital capacity breath techniques in tribal and non-tribal population of Eastern India

“…1 environmental factors, geographical location, occupation, metabolic rate, hemoglobin concentration, functional residual capacity, state of the airway (closed vs. open), physiological shunt and dead space, obesity, pregnancy, critical illness, head injury, neuromuscular paralysis, etc. [3][4][5][6] India has a large diversity of population. This is influenced by different genetic pattern and geographical or regional factors.…”