1. Bernstein, Samantha L. MSN, RNC-OB, IBCLC

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Accurate measurement of vital signs is an essential nursing task. Vital signs present a snapshot of a woman's condition, allowing us to compare their status to norms and to trends in their condition over time. Labor is a rapidly changing and dynamic status; thus, ongoing monitoring is essential for safe care. Monitoring women in labor has many dimensions. Nurses are often challenged to assimilate a lot of information about a woman's status and prioritize certain information. Careful assessment during labor includes the fetus. Choosing which data to focus on is essential to maintaining patient safety and preventing failure to rescue events.


Abnormal respiratory rates are a strong predictor that a woman in labor is experiencing clinical deterioration (Arnolds et al., 2019; Singh et al., 2012), yet it is an underused key to a woman's condition. Despite its importance to determining maternal wellbeing, respiratory rate is the most frequently omitted vital sign (Flenady et al., 2017). There are a many reasons nurses choose not to measure respiratory rate. Many nurses believe respiratory rate does not affect outcomes (Flenady et al.); perhaps due an underlying lack of understanding of the physiology controlling respiratory rate. Some nurses believe that pulse oximetry can be used as a proxy for respiratory rate (Rolfe, 2019). Although pulse oximetry is an accurate representation of oxygen saturation, it can remain normal even as a woman deteriorates due to physiologic compensatory mechanisms.


There are several common methods for assessing respiratory rate. Nurses often count for either 15 or 30 seconds (multiplying by four or two) and some nurses "estimate" based on a woman's overall appearance or prior respiratory rate measurements (Flenady et al., 2017). These methods are not evidence-based and may lead to inaccurate results. One method is timing duration of one breath (in seconds) and then dividing 60 by that number to determine respiratory rate (Takayama et al., 2019). This "quick check" method is more accurate than counting for 15 or 30 seconds and then multiplying (Takayama et al.); however, counting for a full minute is considered the best practice (Flenady et al.).


Both high and low values offer important information about a woman's overall condition. High values may be the first indicator of sepsis. As metabolic acidosis develops, the body uses the respiratory system to maintain homeostasis. Breathing rapidly increases clearance of carbon dioxide so that normal pH is maintained. If tachypnea is missed or ignored, bradypnea may develop on a path to respiratory failure. Although there is no consensus on the normal respiratory rate for women in labor, a range of 10 to 20 breaths per minute provides reasonable boundaries. Values for tachypnea (>20) and bradypnea (<10) are reasonable (Green et al., 2020). Ongoing bradypnea may lead to a failure to rescue event, resulting in maternal death.


Recent reports have increased awareness of the high rate of maternal death in the United States, many of which are considered preventable. Although maternal deaths are multifactorial and require significant study to understand, every nurse can do their part by a "back to basics" approach that includes consistent vital sign assessment and accurate counting of respiratory rate for a full minute.




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